eChapters

Abstract
Food insecurity and malnutrition are on the rise globally, impacting millions, especially in rural regions where extreme poverty and food insecurity are deeply rooted. Vulnerable groups, including women, youth, and indigenous peoples, are disproportionately affected. Producing foo  that meets dietary needs and ensuring its availability in the future is essential for sustainable development and food sustainability. Addressing the growing global food security concerns and supporting the increasing population requires the continual expansion of plant-based proteins’ significance. Legumes are excellent sources of proteins, carbohydrates, and both soluble and insoluble dietary fibers. Legumes, with their high dietary fiber and low-fat content, help maintain body weight and lower the risk of cardiovascular disease. They are also rich in essential minerals such as potassium, calcium, magnesium, phosphorus, and iron, and provide important vitamins like folate, thiamine (B1), riboflavin (B2), and niacin (B3). Additionally, pulses contain various phytochemicals, including phenolics, flavonoids, phytates, lectins, tannins, saponins, oxalates, enzyme inhibitors, phytosterols, and antimicrobial peptides, which offer numerous potential health benefits. These phytochemicals exhibit anti-inflammatory, anticancer, antimicrobial, and anti-ulcerative properties. Incorporating legumes into agricultural systems can foster more sustainable and climate-resilient farming practices. In developing countries, legumes are often used to supplement cereals or starchy foods to combat protein-energy malnutrition, as animal proteins tend to be expensive in these regions.
Keywords: Antioxidants, Food security, Legume, Malnutrition, Healthy diet

Abstract
The United Nations predicts that by 2050, the global population will reach 9.6 billion, leading to urgent challenges such as ensuring food security and reducing greenhouse gas emissions. Climate change, coupled with biotic and abiotic pressures, will significantly impact global food production. Despite advances in agriculture, malnutrition remains a widespread issue, affecting millions, especially in developing countries. Protein-energy malnutrition, which affects over 170 million children and women, poses a significant threat to national economic development, increasing healthcare costs and reducing productivity. One key solution to combating malnutrition lies in promoting legumes (pulses), which are nutrient-dense, protein-rich, and vital for both human and animal consumption. Pulses have been a staple in diets
for centuries, providing essential nutrients like protein, fiber, vitamins, and minerals. They are not only beneficial for human health, reducing the risk of heart disease, diabetes, and cancer, but they also contribute to sustainable agriculture. Legumes can fix atmospheric nitrogen, reducing the need for synthetic fertilizers, improving soil health, and increasing agricultural productivity. However, despite their benefits, pulse production lags behind other staple crops like cereals. With proper management, legumes could play a vital role in alleviating global hunger, particularly in developing countries. Increased awareness and efforts to incorporate legumes into farming systems and daily diets could help meet the growing global demand for nutritious, sustainable food.
Keywords: Climate change, Food security, Global hunger, Legumes, Proteinenergy malnutrition, Sustainable agriculture

Abstract
Remote sensing and image analysis have emerged as essential tools in modern agriculture, particularly for plant protection in grain-based legume cropping systems. These technologies are increasingly valuable in addressing challenges such as climate change, pest infestations, and the demand for sustainable practices. Grain legumes, including peas, beans, lentils, and chickpeas, are vital for global food security and soil health due to their protein content and nitrogen-fixing capabilities. However, their productivity is often threatened by pests, diseases, and weeds. Remote sensing allows for early detection of crop stress through analysis of specific wavelengths of light, enabling farmers to identify issues before visible symptoms appear. Tools like the normalized difference vegetation index (NDVI) provide insights into crop health, allowing for timely and targeted interventions. Hyperspectral and multispectral imaging further enhance disease detection by identifying physiological changes in crops that are not visible to the naked eye. In addition to disease monitoring, remote sensing aids in pest management by detecting changes in plant temperature profiles and utilizing drone surveillance for real-time data collection. Image analysis complements these efforts by offering detailed insights into crop conditions, enabling precision agriculture practices that minimize environmental impact and reduce costs. By integrating remote sensing and image analysis with other technologies like GIS and IoT, farmers can achieve more efficient, sustainable farming practices, ultimately leading to higher yields and better protection for grain legume crops. Keywords: Food security, Remote sensing, GIS, Grain legumes, IoT, Pest management

Abstract
The growing global population has intensified farming practices, increasing the use of fossil fuels and agrochemicals. With limited land and the need to enhance food production, balancing environmental impact, especially carbon footprints, is crucial. Climate-smart mitigation options, with a prime emphasis on crop diversification, can help agriculture adapt to anomalous weather patterns and build resilience. Legumes offer a sustainable solution by reducing greenhouse gas emissions, as they produce 5-7 times less gases per unit area compared to other crops. They aid in carbon sequestration, with soil carbon estimates of 7.21 g kg-1 of dry matter, and save fossil energy by decreasing nitrogen fertilizer use, reducing CO2 emissions by 277 kg ha-1 per year. Legumes play a key role in low-emission farming systems due to their ability to fix atmospheric nitrogen, reducing dependence on energy-intensive synthetic fertilizers. They improve soil health, enhance soil structure, and support carbon sequestration. Integrating legumes into crop rotations reduces the need for chemical pesticides and fertilizers. Additionally, legumes can be used in food, feed, and biofuels, lowering reliance on more carbon-intensive resources. Embracing legumes in farming systems promotes sustainability improves soil health, and considerably reduces the overall environmentalimpact of agriculture.
Keywords: Carbon Footprint, Greenhouse Gas Emissions, Legumes Sustainability

Abstract
The cultivation of grain legumes is expanding globally because of their diverse applications as food for humans, feed for livestock, and raw materials for industrial purposes. Legumes contribute significantly to sustainable agricultural practices due to their unique ability to fix atmospheric nitrogen through symbiosis with rhizobia bacteria in their root nodules. Incorporating legumes into cropping systems in place of traditional cereal-cereal rotations can significantly enhance agricultural sustainability due to their multiple benefits. Their role in nutrient cycling, particularly nitrogen and phosphorus, ensures that subsequent crops benefit from improved soil nutrient availability, making legumes an essential component of crop rotations and intercropping systems. Additionally, legumes improve soil structure, organic matter content, and decrease the environmental impact associated with excessive fertilizer use, such as greenhouse gas emissions and water pollution. With the increasing demand for plant-based foods and the economic challenges of fertilizing cereal crops, grain legumes are anticipated to play a more prominent role in cropping systems, especially in regions where fertilizer availability and affordability are limited. It includes studies on improving nitrogen fixation efficiency, enhancing phosphorus uptake, and developing varieties that are better adapted to specific environmental conditions and cropping systems. Additionally, there is a need to identify the most suitable legume species and varieties for different regions and cropping patterns to ensure maximum productivity and sustainability.
Keywords: Climate change mitigation, Grain legumes, N fixation, P availability, Soil organic carbon

Abstract
The rapid increase in global food demand, driven by fast population growth, has made it challenging to provide nutritionally balanced diets. Pulses offer a promising solution to these challenges by delivering significant nutritional and physiological benefits. Pulses such as chickpeas, green gram, peas, horse gram, beans, lentils, black gram, and others are excellent sources of protein (190-260 g kg−1), carbohydrates (600-630 g kg−1), dietary fibers, and bioactive compounds. The phytochemicals found in pulses, including flavonoids, phenolics, tannins, phytates, saponins, oxalates, peptides, and enzyme inhibitors, offer numerous health benefits. Pulses, essential to human diets for centuries, have seen historically low consumption levels due to underappreciation of their nutritional value. Recognizing their significance, the United Nations designated 10 February as World Pulses Day, and declared the year, 2016 as International Year of Pulses emphasizing their role in promoting healthy diets, sustainable food production, and food security. India is the largest producer of pulses in the world accounting for 25% of the global pulse production. The production and productivity of pulses have slightly decreased due to great emphasis to rice and wheat crops. To boost pulse production, India has implemented initiatives like the National Food Security Mission and policies to support farmers, including Minimum Support Prices (MSP) and welfare schemes integrating pulses. These efforts aim to enhance pulse cultivation, ensure food security, and improve farmer incomes, addressing the demand-supply gap and declining per capita availability of pulses.
Keywords: legumes, sustainable, oxalates, inhibitors, phytochemicals

Abstract
Grain legumes, a group of crops which belong to Fabaceae family, are primarily grown for their edible seeds. Pulses contain a high amount of protein (20-25%), vitamins, and minerals. Consumption of pulses can be beneficial for cardiovascular health, weight management, for diabetics, cancer management, bone health etc. So, grain legumes can play a significant role to address future global food security, environmental sustainability, and nutritional needs. The nutritional value of grain legumes can be significantly enhanced through biofortification, agronomic intervention, processing, and value addition. So, diversification of food habit with pulses and cereals can solve the prolong problem of malnutrition in developing countries including India. Despite such great importance, global food legume production has
been found to increase at a very slow pace. Keywords: Biofortification, Environmental sustainability, Food security, Grain legumes, Nutritional security
Introduction
Grain legumes or pulses are a group of crops which belong to family Fabaceae, are primarily grown for their edible seeds. The common examples of grain legumes include: bean (Phaseolus spp.), lentil (Lens culinaris), chickpea (Cicer arietinum), pea (Pisum sativum), soybean (Glycine max), lupin (Lupinus spp.), broad bean (Vicia faba), igeon pea (Cajanus cajan), grass pea (Lathyrus sativus), black gram (Vigna mungo), green gram (Vigna radiata). Grain legumes can play a significant role to address future global food security, environmental sustainability, and nutritional needs. Pulses are the second most important food crop after cereals and an important source of proteins, vitamins, and minerals. Pulses are popularly known as “Poor man’s meat” and “Rich man’s vegetable”. Pulses contain a high amount of protein (20-25%), which is almost double and triple of the protein content of wheat and rice, respectively and so can contribute significantly to the nutritional security of the country. Besides, they may serve the purpose of protein rich fodder and good quality green manure crop. Pulses can thrive well in low and marginal land with less external inputs. They act as erosion resisting crops because of its deep tap root
system, leafy growth, and close spacing. Pulses can also be grown as paira crop or inter-crop in different growing situations. Being a leguminous crop, it can fix atmospheric nitrogen with the help of its root nodules, resulting in low requirement of external fertilizer. Keeping the importance of pulses in mind, United Nation’s Food and Agricultural Organization (FAO) also declared 2016 as the ‘International Year of Pulses’.

Abstract
Understanding genetic diversity is essential for achieving genetic improvement and conservation of grain legumes. These crops serve as important pulses grown and consumed all over the world, especially in Africa, South East Asia and America. Legumes serve as a good source of carbohydrates, oil, fibre and proteins. Grain legumes are a major source of food and nutrition globally. However, it has not been possible to enhance gain legume production to the required level, primarily due to the narrow genetic base of most of the legume crops, coupled with changing climatic conditions. Most grain legumes are lacking in desired plant ideotypes and resistance sources for various biotic and abiotic stresses. The genetic diversity conserved in gene banks globally is a major resource for crop breeding programs, but it
is utilized only marginally. Therefore, in order to broaden the genetic base of grain legume crops and enhance the genetic gains made in improvement programs, conventional approaches and modern scientific tools should be integrated in a phased and carefully judged manner. The first phase should focus on the search for desired traits and the infusion of diversity into the cultivated gene pool through use of landraces and CWRs. The second phase should focus on the utilization of advanced selection tools, such as genomics, high-throughput precision phenotyping, and artificial intelligence, to exploit the hidden potential of the available genetic diversity; and the third phase should involve technologies such as mutational breeding, genome editing, and transgenic technologies to improve, modify any novel or alien traits that are not available in the entire crop gene pool. We presume that enrichment of the genetic diversity of cultivated grain legume gene pools, along with simultaneous improvements in their yield and plant type with the aid of advanced scientific tools, will enhance grain legume crop yields to the required level.
Keywords: Crop improvement, Genetic diversity, Genome editing, Legume, Phenotyping

Abstract
Global food production needs to double by 50% by the middle of the 21st century to ensure food and nutritional security for 9 billion people. Climate change, particularly atmospheric CO2 and temperature, has a complex impact on sustainable food security. Climate change is a significant constraint on legume production globally, which is a crucial food, feed, and fodder source. Legumes fix atmospheric nitrogen through bacteria in root nodules, reducing greenhouse gas emissions and boosting soil C-sequestration. Climate change positively impacts grain legumes by allowing them to allocate above-ground
photosynthates into below-ground parts (nodules), improving rhizospheres’ activities, plant biomass and nutrient use efficacy. However, temperature can also negatively affect grain legumes, leading to flower abortion and abnormal pod filling. However, climate models predict more extreme events in the future, affecting legume growth and development. Heat stress, elevated CO2 concentration, drought, and rainfall variability impact legume crop production, requiring adaptation options. Results show that legumes with C3 fixation pathways show higher photosynthesis, reduced photorespiration, biomass production, and water use efficiency under atmospheric CO2. However, temperature increases lead to faster development, shorter life cycles, and lower yields. Legumes can cope with atmospheric CO2 up to
1000 ppm by storing sucrose and starch. Protein synthesis and water stress also help legumes adapt to changing climates. To achieve targeted yields in changing climatic conditions, agronomic and genetic interventions must be integrated. Targeted breeding programs should select high-yielding, biotic stress-resistant, and abiotic stress-tolerant genotypes adapted to atmospheric CO2 and temperature conditions. Integrating grain legumes with desirable traits can provide resilience against climate change.
Keywords: Climate change, Grain legumes, Nutritional security, Resilience, Rhizosphere, Water Use Effciency

Abstract
Grain legumes, members of the Fabaceae family, are essential for global nutrition and sustainable agriculture. The legumes such as soybean, chickpea, lentil, pigeon pea, black gram, green gram, faba bean and field peas are renowned for their high protein and energy content. A core aspect of their significance lies in their ability to fix atmospheric nitrogen through symbiotic relationships with Rhizobium bacteria, enhancing soil fertility and reducing the need for synthetic fertilizers. This process, coupled with their role in carbon sequestration, positions legumes as crucial components of sustainable farming systems. Grain legumes, as C3 plants, rely on efficient carbon assimilation to convert atmospheric CO2 into biomass, supported by high nitrogen content for optimal photosynthesis. Additionally, the symbiotic nitrogen fixation within root nodules enables legumes to transform atmospheric nitrogen into forms usable by plants, thereby contributing to soil nitrogen pools and reducing greenhouse gas emissions. By integrating
legumes into crop rotations, farmers can enhance soil health, lower fossil energy inputs, and support ecological sustainability. This comprehensive analysis underscores the critical roles of carbon and nitrogen assimilation in maximizing the environmental and agronomic benefits of grain legumes.
Keywords: Carbon assimilation, Grain legumes, Nitrogen assimilation, Nitrogen fixation, Photosynthesis

Abstract
Biotic stress in plants refers to the adverse impact of living organisms, such as pathogens, pests, and nematodes, on plant growth, development, and productivity. These biotic agents can infect, infest, or parasitize plants, triggering a range of physiological and biochemical responses that compromise plant health. Biotic stress can manifest in various forms, including fungal diseases, bacterial blights, viral infections, insect infestations, and nematode attacks, leading to reduced crop yields, lower quality produce, and significant economic losses. Understanding biotic stress is crucial for developing effective management strategies to protect plants and ensure food security, as it poses a significant threat to agricultural productivity and sustainability. To enhance the productivity of grain legumes, a critical food source for millions, mitigating biotic stress is essential. By adopting effective strategies to manage biotic stressors like diseases, pests, and nematodes, legume yields can be significantly increased.
This can be achieved through the development and deployment of resistant cultivars, integrated pest management (IPM) practices, cultural methods like crop rotation and sanitation, and biological control methods. Additionally, rhizobia and mycorrhizal inoculation can enhance plant defense and nutrient uptake, while precision agriculture techniques facilitate early detection and targeted management of biotic stress. By implementing these approaches, legume productivity can be boosted, ensuring food security, improving livelihoods, and meeting the growing demand for this vital crop.
Keywords: Biotic stress, Integrated pest management, Legume productivity, Sustainability

Abstract
Biological nitrogen fixation (BNF) is a critical ecological process carried out by grain legumes, which form symbiotic associations with nitrogen-fixing bacteria, primarily Rhizobium species. This natural mechanism converts atmospheric nitrogen (N2) into ammonia, a form that plants can readily utilize, significantly enhancing soil fertility and reducing the need for synthetic nitrogen fertilizers. The process begins with the recognition and infection of the legume roots by rhizobia, leading to the formation of specialized structures called nodules, where the bacteria convert atmospheric nitrogen into ammonia through the enzymatic action of nitrogenase. The symbiosis between legumes and rhizobia is tightly regulated by various genetic and environmental factors, including plant signalling molecules, soil conditions, and nutrient availability. Grain legumes, such as soybeans, chickpeas, and lentils, play a vital role in sustainable agriculture by improving soil health, promoting biodiversity, and providing a protein-rich food source. This overview explores the molecular mechanisms underlying BNF, the factors influencing the efficiency of this process, and its potential to enhance sustainable agricultural practices. Understanding the intricacies of BNF in grain legumes can inform breeding programs and management strategies aimed at maximizing the benefits of this natural process for agricultural productivity and environmental sustainability.
Keywords: Nitrogenase, Biological Nitrogen Fixation, Environmental sustainability, Soil fertility

Abstract
Grain legumes face significant biotic stresses fromvarious pests and pathogens, leading to substantial yield losses worldwide. This chapter synthesizes recent advances in molecular approaches and biotechnological tools for developing resistant varieties and managing diseases in legumebased cropping systems. Novel genomic technologies, including CRISPRCas9 gene editing, marker-assisted selection (MAS), and next-generation sequencing (NGS), have revolutionized our understanding of host-pathogen interactions and accelerated the development of resistant cultivars. RNA interference (RNAi) technology has emerged as a promising tool for targeted pest control, while transcriptomics and proteomics approaches have helped identify key resistance genes and defense-related proteins. Integration of these molecular tools with traditional breeding programs has resulted in improved varieties with enhanced resistance to major pests like pod borers and diseases such as fusarium wilt and ascochyta blight. Additionally, biotechnological applications including biopesticides and disease-forecasting systems have strengthened integrated pest management strategies. This review highlights the potential of combining multiple molecular approaches for sustainable pest and disease management in legume cultivation while identifying future research directions and challenges in their widespread adoption.
Keywords: Biopesticides, Biotechnological tools, Marker-assisted selection, Legume

Modern fruit and vegetable processing industry is by and large, employing sophisticated machinery and equipment and efficient technique of production. There is still a scope for expansion of the industry by developing and exporting value-added products and on more foreign exchange. The choice of products to be manufactured will depend on the readily availability of raw materials in the area where the Processing Unit is supposed to be set up and the consumer preference in the neighbouring market. Preservation of food has to be established in the developing countries for other reasons also such as to generate both rural and urban employment, improve farmers nutrition by allowing them to consume their own processed fruits and vegetables during the off- season, stimulate agricultural production by obtaining marketable products, reduction of imports and meeting of export demand and to develop new value-added products. The food processing industry has now become more of a necessity than being a luxury. It plays an important role in the conservation and better utilisation of fruits and vegetables. To avoid the glut and utilise the surplus during the season, it is necessary to employ modern methods to extend storage life for better distribution and processing techniques to preserve them for utilisation in the off season on both large scale and small scale. Fruit and vegetable processing was first started in an organised manner in 1857, mainly to make pickles and chutneys with a view to meeting the export requirement.
Mango Processing Technologies
Mangoes are processed at two stages of maturity. Green fruit is used to make chutney, pickles, curries and dehydrated products. The green fruit should be freshly picked from the tree. Fruit that is bruised, damaged, or that has prematurely fallen to the ground should not be used.

Pectin
Pectin is a component of nearly all fruits and vegetables and can be extracted and used in food processing to form the characteristic gel in jams and marmalade. The richest sources of pectin are the peels of citrus fruits such as lime, lemon, orange and passion fruit or the pulp of apple (known as ‘pomace’ after juice has been extracted). Commercially, pectin is available as either a light brown powder or as a dark liquid concentrate. It is stable if stored in cool, dry place and it will lose only about 2 per cent of its gelling power per year.
There are two main types of pectin:
• High methoxyl (HM) pectin that form gels in high solids jams (above 55% solids) in a pH range of 2.0-3.5; and
• Low methoxyl (LM) pectin, which do not need sugar or acid to form a gel, but instead use calcium salts.

Fruits and vegetables are one of the most consumable commodities globally and also serves as an important ingredient in human dietaries. There are a lot of different varieties of fruit and vegetable and the prices keep fluctuating of the products. The production of fruit and vegetables needs to be handled, processed, or utilized properly. The costs involved in preventing the losses are always cheaper than the cost of production, therefore processing receives higher attention in recent years. The fruits and vegetables processing industry was earlier highly unorganized but due to the increasing demand for processed
food, the industry has started attracting investors. India facilitates the fruits and vegetables processing industry in obtaining its primary resources; India is the second-largest producer of fruits and vegetables. The global fruit and vegetable processing market includes the global fruit & vegetable processing equipment market and processed fruits & vegetables market. There are different methods included in fruits and vegetable processing that helps in increasing the life of seasonal fruits and vegetables are canning, dehydration, freezing, pickling, etc.
Crystallized Fruits
Candied fruit when covered or coated with crystals of sugar, either by rolling in finely powdered sugar or by allowing sugar crystals to deposit on them from dense syrup are called crystallized fruits.

Definition: Food preservation can be defined as the science which deals with the process of prevention of decay or spoilage of food thus allowing it to be stored in a safe condition for future use. All foods gradually undergo deterioration or spoilage from the time they are harvested or manufactured. Some commodities spoil rapidly, while others can keep for longer but limited periods.
Preservation is a set of techniques used to extend the shelf life of perishable fruits and vegetables, maintaining their quality, nutrition, and safety. Proper preservation methods are crucial in post-harvest management to reduce wastage, meet consumer demands, and ensure food security. Let us explore the principles and methods of preservation using easy vocabulary
Principles of Preservation
• Temperature Control: Preservation involves maintaining low temperatures to slow down enzymatic and microbial activity. Lower temperatures can inhibit the growth of spoilage microorganisms and extend the freshness of fruits and vegetables.
• Removal of Air and Moisture: Air and moisture can accelerate deterioration and spoilage. Preservation methods often involve vacuum sealing or drying to remove air and reduce moisture content.

Introduction
With the dynamic change in the pace of human activity and changing life style, the demand for easy-to-prepare drinks is also increasing. Besides being consumed in the household, these drinks are also served in restaurants, clubs, airlines, railways etc. There has been an appreciable increase in the export of processed foods which includes squashes, cordials, and syrups. With the fast pace of growth in the urban sector and the increase in living standards of the Indian people reaching higher levels by the year, there is a good potential to develop this industry in the small-scale sector. To prepare fruits and vegetable juices at commercial level, several equipments are needed. Some of the important equipment required for processing of specific fruit and vegetables are discussed herein.
Pome Fruit and Small Fruit Processing
Generally, most pome fruit (e.g. Apple, Pear, Quince) and small stone fruit (e.g. Plum, Olive, Peach, Cherry) can be used for juice extraction. No peeling is needed. Small stone fruit such as apricots and plums might have to be destoned (pitted) depending on the grinding, extraction equipment selection. Cherries, although containing a pit, may be pressed with the pit intact. Breakage of the pit will release benzaldehyde, the familiar aroma of maraschino- type cherries.

Juice and juice products represent a very important segment of the total processed fruit industry. Juice products are being marketed as refrigerated, shelf-stable, and frozen, in a variety of packages with increased emphasis on functionality, health attributes, new flavors or blends, and in some cases fortified with vitamins and minerals. High-quality juice operations are dependent upon a source of high- quality raw material.
Fruits provide an important source of energy for human beings. But the main drawback is that the availability of majority of fruits is seasonal and they are perishable. Hence, fruits need to be processed and preserved which extends their shelf life and also results in value-addition. India is a producer of many varieties of citrus fruits. Hence, it is sensible if processing industries are set up near the places where the fruits are grown. States like Maharashtra, Uttaranchal, Himachal Pradesh and the North-Eastern states are high producers of many fruit verities. Assam is a major producer of fruits such as pineapple, orange, lemon, mango etc. and it is grown in large quantities over here. Hence, fruit squash and cordial making activity in a small scale is highly recommended in these regions.

There is wastage and loss of food during its journey from production to consumption. Approximately one-third of the massive 1.3 billion tonnes of food produced annually goes to waste due to various factors such as poor
handling after harvesting, unfavorable storage conditions, insect infestations, and diseases. To combat these losses, synthetic chemicals have historically been used to control pathogens and pests, but concerns over their potential health risks have led to restrictions on their usage. In response, researchers are now focusing on developing safer and more effective physical treatments for disinfecting and protecting horticultural produce. This chapter specifically explores the advantages of using heat treatment as one such method, discussing how it helps maintain the quality of fruits and vegetables while simultaneously reducing postharvest losses.
Some of the heat processing methods are discussed below:
Fruit juices, RTS and nectars are preserved by pasteurization or by using chemical preservatives. Squashes, crushes, syrups and cordials are preserved by adding chemical preservative like potassium metabisulphite or sodium benzoate.

Minimal processing of fruits and vegetables
The technological development and modernization during recent years have resulted in in organisation coupled with Lifestyle modification and changes in dietary habits. This development and Organisation have made it easier to meet the requirement of processed food. Processing of fruits and vegetables effects shelf life providing ready to eat food with similarities to fresh product. Before the food Industries shoulder a bigger responsibility of utilising a novel technology to produce safe food without detrimental effects on quality. The industries need to who built biological (enzymatic / fomentation and biopreservation and Engineering solutions like non-thermal high-pressure treatment, cook chill, microencapsulation, vacuum impregnation etc. For the adoption of de - constructive culinary techniques such as 3D food printing and Molecular gastronomy as well as developments in nutrigenomics and digital technologies may facilitate novel product format, personalization, and access to niche market. Concretely, e - operating movement from Naresh mint to health improvement in present conditions demand or shift from defensive market oriented offensive market developing strategies including collaborative networks with Research Organization.
It is also defined as any fruit and vegetable that has been subjected to different processing steps (e.g. peeling, trimming, cutting, washing, disinfection rinsing etc.).

1. Peeling: It is one of the integral parts of a food processing, and most agri-cultural crops need to be peeled to remove at the initial stage of food processing Peeling removes inedible portion (peel, seeds, and stalk) of fruits and vegetables. However, the susceptibility to spoilage increases due to acceleration of physiological process and the exposure of the tissues to microorganisms. The shelf-life and quality of fresh-cu produces could be compromised with the peeling.
The goals of optimum peeling operation are i. Minimizing product losses, ii. Types of products e.g., potato products, iii. Minimizing heat ring formation e.g., apple, potato, iv. Minimizing energy and chemical usage, v. Minimizing the environmental pollution.
Peeling operation can be grouped under following categories: Manual peeling (knife or blade), Mechanical peeling (abrasive devices, devices with drums, rollers, knives or blades and milling cutters), Chemical peeling, Enzymatic peeling, and Thermal peeling (Flame or dry heat peeling, steam or wet heat peeling, thermal blast peeling, and vapour explosion or vacuum peeling.

India produces 146 million tons of vegetables (NHB report, 2011) and the total area under vegetable cultivation is around 8.5 million ha. Potato, tomato, onion, cabbage and brinjal account for around 60 per cent of the total vegetable production in terms of quantity. India’s annual fruit production is 75 million tons (NHB report, 2011) and the total area under fruit cultivation is around 6.3 million ha. The major Indian fruits are mango, banana, citrus fruits, apple, guava, papaya, pineapple, and grapes. Fresh fruits and vegetables play a vital role in Indian context and their marketing works as an influencing force in the economy. Though retailing of fresh fruit and vegetables is a low margin business, the market potential is very large in a country like India. This factor has attracted many corporates into this sector. Marketing of agricultural produce is different and more challenging than many industrial products because of the perishability, seasonality, and bulkiness. The very nature of small size of land holdings by the farmers, varied climatic conditions, production spread over wide geographical area, mainly in remote villages, diversified consumption patterns/habits of the Indian consumers and poor Supply Chain (SC) infrastructure makes marketing for fruits and vegetables more complicated. At the same time, Indian consumers demand fresh fruits and vegetables. Thus, Management plays a crucial role in marketing fruits and vegetables. Supply Chain efficiency not only helps in increased production and per capita consumption, but also contributes to economic development of the country. As a result, Supply Chain Management (SCM) throws both challenges and opportunities in marketing of fruits and vegetables. Efficient SCM in marketing, not only increases the profitability and efficiency of retailers, but also adds value to different stakeholders like cultivators (farmers), consolidators and consumers. Traditional Retail Model of fruit and vegetables is predominantly followed in unorganized retail sector. Players involved in this model are commission agents, auctioneers, wholesalers, traditional retailer of all type of formats family run ‘mom and pop’ stores, roadside shops, pavement shops and cart vendors apart from farmers and customers.

Botanically fruits are ripened ovary. It is a plant part that may or may not be purely derived from ovary of the flowers may be fleshy or pulpy in character, often juicy, predominantly sweet. With somewhat acidic taste, fragrance, aromatic flavours, fruits are generally not consumed during principal part of meals. Whereas vegetable is plant part which is less sweet, generally non acidic and consumed either cooked or raw during the principal part of our main meals. Vegetables may be fruit, root, stem flower, or leaf part of a plant or their modification.
Fruits and vegetables are valued in in human diet as an important source of protective nutrients like Minerals and vitamins. Apart from their nutritive value they add variety to the diet and improve acceptability of meal due to presence of different shades of colours, flavours, and texture. However, the major role in food preservation is played by their moisture content. For the same reason they are classified as
1. Perishable: Those which deteriorate quickly after harvesting such as tomatoes, mangoes, papaya, peaches, plums, juicy fruits and vegetables. They have high degree of moisture content and are highly susceptible to spoilage.
2. Semi perishable: These have less moisture content as compared to perishable one’s example 30 carrots, peace, green beans, apple etc. These foods are containing certain natural inhibitors to spoilage.

The term food processing covers an enormous field from simple boiling to the use of irradiation to predict the consequences on the nutritional value of fruits and vegetables. Generally, the food processing methods can be categorized as in intentional processing method (milling, peeling, washing trimming etc.), inevitable processing method (blanching, sterilizing, cooking, shredding, and drying) and accidental (inept processing or system). The nutritional losses associated with fruits and vegetable processing with different processing techniques and conditions employed. For example, the heavily processed products are although safe for human consumption but allied with reduced nutritive value. In this regard access to safe and nutritious food is considered as a basic right of humans as it is one of the ways to prevent various ailments by building better health and enforcing immunity. Escalating help awareness has guided the processes to opt for minimal processing food in recent years.
Food commodities subjected to minimal processing are capturing the market Suring to widespread concept that they might help in meeting the current requirement of vital nutrients. Development of minimally processed commodities especially fruits and vegetables have augmented at both retail and consumer levels during last years. Various organisations WHO, FAO, USDA boost up the utilization of minimally processed perishable commodities including vegetables and fruits to lessen the risk of cardiovascular diseases and cancer. Changes occurring in the eating habits have been quoted due to high anxiety for on time availability of these minimally processed fruits and vegetables. Sales of fresh cut fruits and vegetables continue to burgeon and food industries are persistently expanding primary because of consumers’ trend of health realization.

India is known as the food basket of the world. It is the second largest producer of fruit till now after China, but its contribution to the Global market of fruit processing is just 1per cent. This is due to the fact that there is deficiency of skilled manpower, poor cold storage facilities, inefficient post-harvest management and minimal technological interventions.
Deficiency of the skilled manpower: In-spite of market size of US dollar 181 billion, expenditure on food and food products being 21per cent of India’s GDP and more than 31per cent share of wallet by consumers, there is resultant apprehension about the emergency emerging skill shortages due to mismatch between the demand for specific skills and available supply. Shortage of skilled, Semi- skilled and unskilled workers has emerged as a critical factor impacting the competitiveness of Indian food industry. Efficient man-power is one such critical element to improve to foster the growth. As the food industry advances and adopts various levels of automation the demand of skilled manpower will increase phenomenally. Hence if, the Indian food industry must achieve projected growth target set and become globally competitive, the need to develop and train the human resource efficiently would be essential.

A cut-out examination is conducted for the evaluation of canned fruit and vegetables and other products for various quality attributes, viz., physical, chemical, sensory, and microbiological attributes. The examination is conducted by following the undermentioned steps: External/physical examination of unopened Can
1. External Appearance of the tin can: Note the external condition of the tin can like dents, rusty spots, scratches, leakage around seams, and the condition of ends. Based on external appearance describe the condition of the tin can by using the following terms:
i. Flat Can: A can where both ends are concave. The vacuum is high enough to maintain the ends concave.
ii. Flipper Can: A can where the vacuum is so low that mechanical shock will produce distortion of one or both ends.
iii. Springer Can: A can in which one end is distorted and the other end is flat and pressure on the convex end will cause the flat end to spring out when pressed.

Drying and dehydration are interrelated terms. Drying generally refers to the method of removal of moisture from the food under natural conditions such as sunlight and wind for example open sun drying, shade drying etc. Whereas, dehydration refers to a process of removal of moisture by application of artificial heat under controlled conditions of temperature and airflow. In this case single layer of fruit and vegetables, either whole or sliced after primary pretreatments is spread on trays which are placed inside the dehydrator or in the open sun for drying. In the dehydrator, the initial temperature is generally kept at 43oC which is then gradually increased to 66-71oC for fruits and 60- 66oC for vegetables. Dried grapes (raisins and monucca), apricots, dates, apple rings/cubes, Morchella (Guchhi), bael, aonla, fig, green peas, cauliflower, cabbage, onion, garlic etc are commercial products prepared by using drying.
Procedure for drying: Drying generally involves three stages: pre-drying treatments or pre-treatments, drying of commodity and post-drying operations such as handling, packaging and storage. The flow sheet for drying of fruit and vegetables is shown in Figure 1 and details of pretreatments for drying fruits and vegetables are shown in Table 1&2 respectively.

Tomato, apple, plum, mushroom, etc., are used successfully for the preparation of sauces. Sauces are of two kinds 1) thin sauces consisting of vinegar extracts of flavoring material like herbs or spices and 2) thick sauces which are highly viscous.
Sauces are prepared by maceration of spices, herbs, fruits, and vegetables in cold vinegar or by boiling. Thickening agents like pectin, carboxymethylcellulose,n etc., are also added to sauces to prevent the sedimentation of solid particles. The sauce is generally cooked to such a consistency that it can be freely poured without fruit tissues.
Procedure
Tomato fruits are washed, cut into pieces, and heated/boiled for about 10 minutes in their own juice in SS pan to soften the tissue. The heated fruit mass is passed through a pulper to separate skin and seeds. Half of the sugar and spices are placed in a muslin cloth bag which is then immersed in the pulp during cooking. Cooking is continued till the pulp is reduced to half of the original volume.

Preserve (Murabba) is made by cooking the fruit either whole or in slices/ pieces in sugar syrup of heavy concentration (65-70oBrix). Usually for 1 kg fruit around 1.75 kg sugar is used and the cooking is continued till the TSS reaches 68oB. Fruits like petha (ash gourd), aonla, bael, apple, pear, karonda, pineapple and papaya etc., are used for making preserve/murabba.
Candies are also prepared similarly but the TSS is maintained up to 75-80%. For candy preparation, the fruit pieces are dipped initially in 55-60% sugar solution and the TSS of the syrup is increased by 5% everyday up to 4-5 days and then the fruit slices are drained free of syrup and dried in driers. Fruits like aonla, karonda, cherry, apple, ginger peels of orange, lemon, and grapefruit etc., and petha (ash gourd), are used for candy preparation.
Selection and preparation of fruits: Wash the fruits in water to remove dirt and residues. Peel, core and cut the fruits into pieces. Pricking should be done with stainless steel forks. In case of petha (ash gourd), after pricking place them in lime water

Fruit syrup is a beverage that contains at least 25% fruit juice/pulp, 65% total  soluble solids and acidity ranging between 1.2 -1.5%. It is preserved by using
350 ppm SO2 or 600 ppm benzoic acid. Fruit syrup is diluted before serving. Syrup can be made from the juice/pulp of jamun, ginger, lemon, phalsa, rose extract, bael, pomegranate, and brahmi (Bacopa monnieri) leaves/root extract, etc. Besides, a syrup/sharbat containing a minimum of 10 per cent of dry fruits is also regarded as fruit syrup.
Recipe: The generalized recipe for the preparation of syrups from different fruits is as under:

Fruit chutney is a product made in the same way as jam except that spices, salt, and acid (vinegar) in addition are added. The total soluble solids in chutney are] also less than that of jam. The product shall be of good quality with a palatable and appetizing taste. As per Food Safety and Standards Regulations, chutney\ shall contain a minimum of 40% fruit (w/w) in the final product with total soluble solids not less than 50%. The acidity in the final product shall not be more than 2% with ash content not exceeding 5%. However, for vegetablebased chutney as well as hot & sour (spicy) chutney, the TSS shall not be less than 25%.
Recipe: The generalized recipe for the preparation of chutney from different fruits is as under:

Marmalade is a fruit jelly in which the slices of peel are suspended. The marmalades are prepared generally from citrus fruits like orange and lemon. The pectin and acid contents of the marmalades should be kept slightly higher  than that for jellies. Citrus marmalades are of two types: i) Sweet marmalade and ii) Bitter marmalade.
Procedure
Preparation of fruit extract: After washing the fruit, remove the outer yellow flavedo portion of the peel of citrus fruits thinly which contains colouring matter and volatile oils, whereas the inner white albedo portion contains pectin. The thin yellow peel is cut into fine shreds with a knife, or on a shredding machine, and the shreds are boiled and drained to remove the bitterness. The sliced or crushed fruit is boiled gently by simmering with 2 or 3 times its weight of water to extract the pectin. While it is being boiled, a teaspoonful of the clear extract is taken from the pan and tested with alcohol for its pectin content. The process usually takes 30 to 45 minutes.

Jelly is prepared by boiling the fruit with or without the addition of water, straining the extract, and mixing the clear extract with sugar followed by cooking the mixture to a stage at which it will set to a clear gel. The jelly should be transparent, well set, but not too stiff, and have an original flavour of the fruit. It should be attractive in colour and should keep its shape when removed from the mould. As per FSSAI specification, the quantity of fruit and soluble solids in the final product (jelly and marmalade) shall not be less than 45 and 65 per cent (w/w) respectively. Jelly is made from fruit extract while jam is made from fruit pulp, therefore, jelly in contrast to jam is considered to be transparent and clear in appearance. Guava jelly is the most common commercial product.
Jellies: In the preparation of jellies, pectin is the most essential constituent which help in making the gel. Since, pectin is present in the cell walls of fruits as such fruit peel, whole or fruit slices along with a small quantity of water are gently boiled to extract the maximum proportion of pectin solution in the water extract. This water extract is used for the preparation of jelly.

Jam is prepared by boiling the fruit pulp with a sufficient quantity of sugar to a thick consistency, firm enough to hold fruit tissues in position. For the preparation of jam, not less than 45 parts of fruits are used for every 55 parts of sugar. The jam prepared by using two or more fruit pulps is called mixed fruit jam. Apple jam, apricot jam, mango jam, guava jam, pineapple jam, and mixed fruit jam prepared by using the pulp of two or more fruits are quite common. According to Food Safety & Standards Regulations,2011 the minimum TSS in the Jam shall not be less than 65%(w/w). Earlier the minimum limit was 68% (w/w)
Raw material, ingredients and utensils required
1. Fruits like mangoes, guava, apples, apricots, plum, peaches and kiwi etc singly or in combination
2. Stainless steel knives, de-corers, ladle, utensils for cooking and mixing, glass bottles (Jars), LPG or Diesel Bhatti, bucket/tub for washing, Stainless steel sieve, Steam Jacketted Kettle, Boiler (for the commercial unit) etc. 

Fruit nectar is a type of fruit beverage that contains not less than 20% fruit juice or pulp, not less than 15o B total soluble solids and acidity ranging between
0.3-0.5 % but not exceeding 1.5%/. For orange and pineapple nectar, the fruit juice shall not be less than 40%. The product is preserved by heat processing/ thermal processing, as such no chemical preservative is permitted in nectars. Unlike squashes, fruit nectar is served chilled as such without any dilution.
Mango, guava, pineapple, papaya, jamun etc., are the most suitable fruits for making nectar.
Recipe: As a general guideline, the following recipe is used for the preparation of fruit nectar:
Procedure
i. Select fully mature and ripe fruit and extract pulp as discussed under fruit pulp making but do not add any chemical preservative.

Ready -to -Serve (RTS) drink is a type of fruit beverage that contains at least 10% fruit juice/pulp and 10o Brix total soluble solids with acidity ranging between 0.3-0.5%. The product is not diluted before serving like squash; hence it is called a ready-to-serve beverage. The product can be preserved by using 70 ppm SO2  or 120 ppm benzoic acid. Mango, orange, guava, lemon, lime, litchi, kiwi fruit, apricot, pineapple, etc., fruits are used for making RTS beverages. For lime & lemon drinks minimum level of juice content is 5% as per Indian Food Laws.
Recipe: As a general guideline, the following recipe is used for the preparation of ready-to-serve drinks:
Procedure
i. Select fully mature and ripe fruit like mango, guava, apricot, kiwi, etc., and wash thoroughly.
ii. Some fruits like mango, kiwi, pineapple, and litchi are peeled before heating. Apricots, guava, plums etc are not peeled. Place fruit after peeling in a pan/pressure cooker and boil till softening

Cordial is a sparkling, clear, sweetened fruit juice beverage from which pulp/ fibrous material has been removed completely. It contains at least 25% fruit juice, 30% total soluble solids (TSS), 1.5% acid and 350 ppm sulphur dioxide. Lemon and lime are the most suitable fruits for making cordial.
Recipe: The recipe for the preparation of cordial as a general guideline is as under:
Extract the juice from lime or lemon as in squash and store in glass bottles after adding potassium metabisulphite @ 1.0 g/kg of the juice. Allow the juice to settle for a month. Decant the clear juice without disturbing sediments and strain it through a fine muslin cloth. Prepare syrup by mixing sugar with water, boil, strain and allow to cool. On cooling, mix juice in syrup and strain the cordial through muslin cloth if necessary. Add KMS and fill into bottles. Stor in a cool and dry place.

Squash is a type of fruit beverage containing at least 25% fruit juice/pulp, not less than 40% total soluble solids (TSS), about 1-1.5% acid and not exceeding 350ppm sulphur dioxide or 600ppm sodium benzoate. Squash is diluted by adding cold/chilled water before serving (1:3).
Mango, orange, lemon, lime, litchi, guava, pineapple, jamun, plum, apricot, rhododendron petals etc., are used for making squash. Potassium metabisulphite (KMS) is generally used as a preservative, whereas sodium benzoate is used as a preservative in squash made from coloured fruits like plum, jamun, phalsa and rhododendron petals.
Recipe: A generalized recipe for the preparation of squashes from different
fruits as a general guideline is as under:

Fruit pulps are semi-finished products that are used for manufacturing finished value-added products like jam, ready-to-serve beverages, squash, appetizers etc. According to Food Laws, pulp refers to an unfermented but fermentable product, pulpy, turbid or clear, obtained by a mechanical process from sound ripe fruits/vegetables. These are preserved either by heat processing or by using chemical preservatives. The maximum preservative permitted under Indian Food Laws is 1000 ppm sulphur dioxide added in the form of potassium metabisulphite.
Mango, guava, apple, pineapple, papaya, bael, guava, peach, plum, apricot etc., are the most suitable fruits for making pulp for use in finished product preparation.
Procedure
i. Select fully mature and ripe fruit like mango, guava, apple, peach, apricot, kiwi, etc., and wash thoroughly.

The term canning refers to a process that involves heating foodstuff in hermetically sealed containers for a specific time at a specific temperature to eliminate microbial pathogens that endanger public health; and microorganisms and enzymes that deteriorate food during storage.
Principle of canning: Destruction of micro-organisms causing spoilage, within the sealed containers using heat.
Canning Process
Preparation of food commodities for canning consists of selection of commodities, washing, sorting, grading, peeling, halving, blanching, filling into cans, filling hot syrup or brine, exhausting, double seaming, Sterilization/ processing, cooling, storage, etc.
Raw material selection
Fruits should be ripe but firm, evenly matured, and free from blemishes, insect damage, and malformation. Apple, pear, peach, and banana harvested at the mature stage are preferred for canning.

Starch is the storage form of carbohydrates in plants which is abundantly found in roots, tubers, stems, fruits, and cereals. It is a polysaccharide made up of glucose monomers with a chemical formula of (C6H10O5)n. Starch is composed ofamylose and amylopectin. The linear polymer amylose is the most basic form of starch while amylopectin is the branched form. Foods that are high in starch content are a good source of nutrition. Food starches are used in the food industry as thickeners and stabilizers. During the ripening of fruits, the starch is converted into sugars. Therefore, the presence of starch in fruits is used as an indication of maturity and ripening.
Principle: For estimation of starch contents, the sugars present in the sample are leached out and starch is hydrolyzed using either acid or enzymatic hydrolysis. Stach is then calculated as invert sugars.
Starch content by Acid Hydrolysis method
Reagents: Ethanol 95%, /50%,Concentrated HCl, Concentrated H2SO4, 1N NaOH solution, Phenolphthalein indicator, 10% alcoholic solution of Alphanaphthol.

Sulphur dioxide is used as a preservative in many fruit and vegetable products. It can be added either in the form of potassium metabisulphite or by exposingthe product to sulphur fumigation by burning sulphur powder. Food safety and standards regulations have specified the maximum limit of sulphur dioxide in the finished products. Products having sulphur dioxide content exceeding the limit are considered not conforming to Indian Food Laws. Therefore, the estimation of sulphur dioxide in food products is considered an important attribute for quality evaluation.
Principle
Sulphur dioxide added to the food products may exist as undissociated sulphurous acid, as free bisulphite ions, as free sulphite ions and/or as combined SO2 in the form of hydroxy sulphonates. Sulphur dioxide is measured as free or total SO2.
Free SO2 is measured by direct titration with iodine. In the estimation of total SO2, the combined SO2 is liberated by treatment with excess alkali at room temperature, followed by subsequent acidification to prevent recombination and titration with iodine. The method used is known as the Modified Ripper Titration Method.

Sodium benzoate is added to many fruit products to act as a preservative for the extension of the shelf life. Food Safety and Standards Regulations have specified the maximum level of sodium benzoate (Benzoic acid) in different products like sauce, ketchup, pickles, squash, etc. Therefore, the estimation of sodium benzoate (benzoic acid) in such products is considered a routine quality control procedure.
Principle
Benzoic acid which is sparingly soluble in water is converted into watersoluble sodium benzoate by the addition of NaOH in a sample containing sodium chloride solution. When the Sodium Benzoate solution is acidified with excess HCl, water-in-soluble benzoic acid is formed which is extracted with chloroform. The chloroform is removed by evaporation and the residue containing benzoic acid is dissolved in alcohol and then titrated with standard NaOH.

The use of salt (Sodium Chloride) in food products is an important method of preservation. It not only imparts taste to the products but also helps in checking spoilage of fruit products. Salt is added to pickles, sauces, chutneys, ketchup, and many other products. Food Safety & Standards Regulation has specified the maximum limit of salt in different products. Therefore, the estimation of salt content in food products is considered as an important attribute in food quality control.
Direct Titration Method
Direct titration (Mohr’s) method is used for the determination of salt content in food products as a routine quality control. In this method, the sample is titrated against a standard solution of silver nitrate for the estimation of salt.
Reagents
0.1 N NaOH, Phenolphthalein 1% indicator solution
0.1N Silver nitrate (AgNO3)
5% Potassium Chromate

Fruit, vegetables and their products are important sources of ascorbic acid. Aonla, guava and citrus fruits are good sources of Vitamin C (Ascorbic acid).Ascorbic acid is sensitive to heat, light and oxygen but is stable in acidic
 media. The methods for estimation of Ascorbic acid are based on the reduction of 2,6 -dichlorophenol - indophenol dye by ascorbic acid and those based on the reaction of dehydroascorbic acid with 2,4- dinitrophenylhydrazine. However,the 2,6 -dichlorophenol - indophenol dye reduction method is most commonly used in the estimation of ascorbic acid in fresh fruit and vegetables and their processed products.
2,6 dichlorophenol - indophenol visual titration method
The dye, which is blue in an alkaline solution and red in an acid solution, isreduced by ascorbic acid to a colorless form. The reduction is quantitative and specific for ascorbic acid in solutions in the pH range of 1-3.5.
Reagents
i. 3% Metaphosphoric acid (HPO3) solution:Dissolve 3g sticks/ pelletsofMetaphosphoric acidin a volumetric flask and make volume to 1oo ml with glassdistilled water.

In fruits, vegetables, and their products, the sugars are estimated as reducing sugars, non-reducing sugars, and total sugars. Reducing sugars in fruits and their products represent glucose and fructose. A combination of reducing and non-reducing sugars gives total sugars, whereas non-reducing sugars mainly sucrose are calculated after deducting the value of reducing sugars from the total sugars as invert sugar and multiplying the remainder with a factor of 0.95. Many fruit, vegetables, and their products like jam, jelly, juice, preserve, candy, fruit toffees, etc., containing substantial amounts of sugars, are estimated as a routine by using Lane and Eynon’s method using Fehling’s solution. However, for products having a smaller quantity of sugars, more precise methods like colorimetric methods can be used.
Method: Lane and Eynon’s Method
Principle: Invert sugar reduces the copper in Fehling’s solution to red, insoluble cuprous oxide. The sugar content in a food sample is estimated by determining the volume of the unknown sugar solution required to completely reduce a known volume of Fehling’s solution. Glucose, fructose and other] sugars capable of reducing oxidizing agents are called reducing sugars and this property is used for the estimation of sugars.

pH is important as a measure of active acidity which influences the flavour and palatability of the product and affects the processing requirements. This is an indicator of the acidity or alkalinity of the solution. It is also taken as the measure of the sourness or tartness of the given sample. The pH of a solution varies from 0 to 14. Solutions having a value of pH ranging from 0 to 7 on the pH scale are termed as acidic and the value of pH ranging from 7 to 14 on the pH scale are known as basic solutions. While, solutions with a pH value equal to 7 on the pH scale are known as neutral solutions. Samples with a pH value equal to 0 are known to be strongly acidic. Further, the acidity decreases as the value of pH increases from 0 to 7 whereas, solutions with the value of pH equal to 14 are termed as strongly basic solutions.
Most fruits have a pH value ranging between 3-4, with citrus fruits exhibiting a pH of up to 2.0. Vegetables may exhibit a pH of up to 6.0, as such they are classified as non-acid or low-acid foods. Based on pH value, most fruits, vegetables, and their products are classified into four arbitrary groups such as low acid (5.3 and higher); medium acid (5.3-4.5), acidic (4.5-3.7), and high acid (3.7 and lower). pH value of some fruits, vegetables, and their products is given as under:

Most of the fruit, vegetables, and their products contain acid or a mixture of acids. These acids are mainly responsible for the tartness or sour taste. The level of acidity is estimated to measure the degree of tartness/sourness in the product.
Principle
Acidity in the sample is measured by titrating a known volume of sample against a standard alkali solution of known concentration using phenolphthalein as an indicator. The appearance of a light pink color indicates the endpoint of titration. However, for highly colored products like tomato sauce/ketchup, jamun juice, Rhododendron juice, mixed fruit jam, etc., accurate determination of endpoint may be difficult by using an indicator. Therefore, for such samples, acidity is measured by using electrometric methods i.e. titration to a predetermined pH value, or the sample is further diluted with distilled water to mask the interfering color. The level of titratable acidity is expressed in terms of the predominant acid. Different fruits, vegetables, and their products have different predominant acids. A list of some products having predominant acid is shown as under: