eChapters

Postharvest loss of fruits and vegetables is defined as “that weight of wholesome edible product (exclusive of moisture content) that is normally consumed by human and that has been separated from the medium and sites of its immediate growth and production by deliberate human action with the intention of using it for human feeding but which for any reasons fails to be consumed by human.” Not only quantity and quality but even the appearance of fruits and vegetables are affected, and their market value is reduced. Most ‘skin deep’ injuries such as ‘fly speck’ in apples do not affect the edible part. Some infections are not harmful as they occur on inedible parts and can be trimmed off before consumption ego Colletotrichum spots on the outer leaves of cabbage]. Fresh fruits and vegetables are perishable and highly prone to these losses because they are composed of living tissues. These tissues must be kept alive and health throughout the process of marketing. These are composed of thousands of living cells which require care and maintenance (Alao, 2000). The pathological rots are the most serious which is followed by mechanical injury. Pathological rots in combination with mechanical damage cause serious damage to the perishables. Environmental factors such as temperature, relative humidity and oxygen balance most especially during storage are also greatly responsible for damage also environmental conditions such as temperature and humidity are responsible for rendering fruits and vegetables susceptible for pathological attacks (Yahaya and Mardiyya, 2019). Fungi and bacteria are the major pathogens, which cause postharvest diseases in crops leading to about 30 % loss. Normally diseases will be more at improper temperature and relative humidity. Apart from causing disease, pathogens are also involved in ethylene production, which hastens the deterioration of the product.

1. Multiple Choice Questions

Aerides

Aerides consists of more than 60 species. These are monopodial epiphytic orchids grown on trunks or branches of trees.  The stems are round, leafy and branched with aerial roots. The strap leaves are thick, leathery and bilobed. The inflorescence is auxillary and drooping. The flowers are many and 2cm in diameter closely set on the inflorescence and generally fragrant.

A. Mixing and Homogenization

1. I.ntroduction to Mixing and Homogenization

In the food industry, mixing and homogenization are fundamental procedures that are essential to the production of a wide range of food items. To produce the desired qualities and final result with uniformity and consistency, various ingredients are blended. Ensuring product quality, stability, and customer happiness are contingent upon these processes.

Importance of Mixing and Homogenization

Mixing and homogenization are paramount for several reason

Jay et al., (1995) and Joerger et al., (2003) have written the role of bacteriocins as an alternate to antibiotics. Bacteria produce bacteriocins which are proteinaceous in nature or peptidic toxins. These inhibit the growth of similar or closely related bacterial strain(s). There are different types of bacteriocins which are classified based on the producing strain, common resistance mechanisms and mechanism of killing. Ahmad et al., (2013) have isolated antifungal compound for food preservation. Martin et al., (2018) and Batish et al., (1997) found antibacterial compounds from fungus. Mahboubi et al., (2019) studied the potential of Zataria in IBS. There are bacteriocins from gram-positive bacteria known as the colicins, the microcins and the bacteriocins from Archaea (Cascales et al., 2007). The bacteriocins from E. coli are called colicins (formerly called ‘colicines,’ meaning ‘coli killers’). These have been studied widely. Earlier called colicin V and is now known as microcin V. It is very small and is produced and secreted in a different manner than the classic colicins. Adrienne et al., (2016) have studied the colicin resistance.

Postharvest losses of fruits and vegetables are even higher and are estimated to be 40-50%. Postharvest fruit rotting are a major cause of those losses and are chiefly caused by fungal pathogens after fruit ripening. In a manner similar to foliar diseases that occur in the field, several factors as fungal pathogenicity, host response and environment determine the outcome of host resistance or susceptibility. However, in postharvest diseases fruit ripening is another major component that will determine fruit resistance. The molecular trigger induces the germ tube to differentiate an appressorium. It has been shown that excess nutrients over ride it and protein synthesis is not required once germination has occurred. Protein synthesis during conidium germination and appressorium formation on cellulose membranes were observed (Pathak, 1997). A specific polypeptide (95 kDa) was synthesized only when appressoria matured (a period lasting from 12-24 h after germination). This molecule is involved in the synthesis of the melanin precursor, Scytalone.

Appressoria grown in the presence of cyclohexamide do not mature nor they subsequently differentiate a penetration peg. Appressorium maturation involves the formation of melanin. It has been shown that melanization of appressoria is necessary for formation of a successful penetration peg. The melanin appears to give the appressorium mechanical strength, but pigmentation is only one factor required for penetration competent appressoria. At restrictive temperatures, pigmentation of conidia of C. lagenarium mutants could be restored with dihydroxyphenylalanine without restoration of appressorial competence. Non-pathogenic mutants have been used to determine factors important for pathogenicity. Cutinase production was essential for penetration of papaya fruits. The cutinase produced during infection of papaya fruit by C. gloeosporioides has been purified and characterized as a glycoprotein of 24 kDa. Polyclonal antibodies raised against this enzyme do not cross react with cutinase from Fusarium so/ani, and lesions do not develop when papaya fruits are inoculated with spore suspensions containing the antibody preparation.

Introduction

    1.    Food Science is the application of the physical, biological and behavioral science to the processing and marketing of foods (Margaret, 1968).

    2.    Technology can be defined as the science dealing with knowledge of doing things efficiently and effectively.

    3.    Food science helps us understand the theory example: what methods can best be used to store and preserve food to maintain quality and prevent spoilage.

    4.    Food technology demonstrates how the food is stored, preserved, processed and transported and has been responsible for development of new techniques for processing and preservation of food on a commercial scale and for packaging it in such a way that it can be sold conveniently.

    5.    Food science deals with the study of facts of the physical, chemical and biological sciences as they influence the processing and preservation of food.

    6.    Food technology deals with engineering and other scientific and technical problems involved in transforming edible raw materials and other ingredients into safe, nutritious and appetizing food products (Desrosier, 1977).

    7.    Food science is concerned with basic scientific facts about food, where as food technology concerned with the processing of raw materials into foods that meet human needs and wants.

    8.    Indian agriculture has undergone a sea change during the past half a century. Starting with the campaign for “grow more foods” in the forties, India reached self sufficiency during the eighties.

1. FOOD AND ITS SIGNIFICANCE

Food is the basic necessity of all the living world and the man is no exception to this. The basic purpose of food is to provide energy for the routine body functions and protect the body from various diseases. Life cannot be sustained without adequate nourishment for a healthy and active life, diets should therefore, be planned and consumed on sound nutritional principles (Fig. 1). For want of nutritious foods, consequence is the prevalence of malnutrition. There are several diseases that are related with deficiency of nutrition food, if not consumed. Such diseases include Kwashiorkor that can develop in children consuming insufficient protein even if total calories are sufficient. Marasmus is often due to the cessation of breast feeding and the attempt to replace it with foods, inadequate in protein such as rice broth. Other nutritional diseases still found particularly in the developing world are childhood blindness (vitamin A deficiency), rickets (vitamin D deficiency), beri-beri and infantile beri-beri (inadequate thiamin intake), pellagra (inadequate niacin intake), anemia (iron deficiency), goiter (iodine deficiency), etc. To cope up with this, the diet needs to be supplemented with nutritious food components including fruits and vegetables to make it more suitable for the growth and development of body.

Out of different types of foods, the fruits and vegetables constitute an important component of the food. Horticultural crops occupy a prominent position both in the importance and production in the world. The temperate fruits and vegetables are an important part of the horticultural crops, in terms of production and role in human health. These crops assume all the more importance due to their antioxidant activity, and presence of minerals and vitamins. Both fresh and processed fruits and vegetable, their different products are consumed. They are also called as protective foods. Fruits and vegetables are major sources of important vitamins like B and C and minerals such as Ca, Fe, P and K.

    1.    Wohler (1828) synthesized the first organic compound, urea from inorganic components.

    2.    Emil Fischer (1894) demonstrated the specificity of enzymes and the lock and key relationship between enzyme and substrate.

    3.    Michaelis and Menten (1913) developed kinetic theory of enzyme action

    4.    Watson and Crick (1953) Proposed the double-helical model for DNA structure

    5.    Ingo potrykus (1999) Golden rice- rich in b-carotene.

    6.    Glyoxysomes : Glyoxysomes are temporary in that they occur during transient periods in the life cycle of a plant such as in certain beans and nuts which store fats in their seeds as energy reserves. Glyoxysomes appear in the first few days after seed germination in endosperm cells and associate closely with lipid bodies. They disappear after the storage fats are broken down and converted into carbohydrate.

4.1 Overview of Concept and Science

Preserving flowers and plant parts has been a form of artistic expression that was very popular in Victorian ages. Now, this process is moving from an art to a highly interdisciplinary science and has become a major economic activity on a global scale. Because, dry decorative products have been globally accepted as natural, eco-friendly, long lasting and inexpensive as compare to fresh flowers and plant parts, which are perishable and delicate in nature. These perishables cannot retain their fresh like appearance and beauty for several months and it becomes prodigious job to maintain these qualities. Even with preservatives, the vase life of fresh cut flowers has been prolonged to an extent of 40 per cent only. Hence, for those who want the beauty of nature around them in the form of flowers but on a more permanent basis dried flowers are a solution.

Domain of Dried Flowers

Anything from botanicals such as stems, twigs, branches, bark, leaves/ foliage, flowers, thorns/ spines, fruits, cones, seeds, roots; and minor forest products like lichens, fleshy fungi, mosses, selleginnela ferns etc. in a dried form come under the domain of dry flowers. Until a few years ago dried flowers were popular in the West with very few homes in India opting for them. But, today Indian homes have taken to dried flowers in their many forms and shapes like duck to water. There are different segments which are covered under dried flowers (Table 1).

1. MATURITY INDICES

Maturity indices (right time of harvesting) are quality factors that give clues as to when a product should be harvested to allow marketing flexibility and ensure the attainment of minimum acceptable quality to the user. It also refers to the set of criteria used to determine the stage of maturity for harvesting the horticultural crops. Commodities harvested either pre-mature or too late are more susceptible to postharvest physiological disorders, diseases and have poor shelf life than harvested at right stage of maturity. The pickers/ handlers are trained in methods of identifying produce that is ready for harvest. However, optimum harvesting stages depends upon type of produce and their final use. Horticultural crops may be harvested at two main maturity levels i.e., physiological maturity and commercial or horticultural maturity. Therefore, the proper stage/maturity indices for harvesting of all horticultural crops should be identified for their implementation during harvesting. Horticultural maturity in relation to developmental stages of the plants is depicted in Fig 3.1.

    1.    What is the percentage of water in an adult’s body weight
        a)    50%    b)    60%
        c)    90%    d)    70%
    2.    __________ is a direct reactant in hydrolytic processes of many foods
        a)    Water    b)    Moisture content
        c)    Both a&b    d)    None
    3.    The bond angle of the isolated water molecule (vapor state) is
        a)    109°    b)    104.5°
        c)    109°28'    d)     103.6°

3.1 Introduction

Flower and plant part based perfumes are receiving special attention at this modern age of civilization. With pre-eminent senses of smell or taste, a large brain affording a superior intellect, would lead to the use of these abilities to improve the environment, the flavour of food and the smell of the surroundings. In fragrance industry, essential oil is a generic term given to all fragrant extracts such as essential oils, absolutes, resinoids, concretes etc. Since antiquity, flowers and plant parts have been used as flavours for food, for religious rites, for beautification of homes and gardens, as incence and insect repellent, in cosmetics and personal adornment and in medicine. Fragrance compositions are used with the purpose to affect customers through their sense of smell and the job of composing fragrances is left upto an expert known as “Perfumer”.

Despite continuing invention of synthetic fragrant extracts, natural essential oils still remain the most important part of fine fragrance. Essential oils are so aromatic and are the focus of the fragrance industry. The content of a pure essential oil product gives it an unmistakable aromatic and healing quality. Nature has always provided us with food, medicine and fibre for clothing that we need to survive. Sometime a walk in the woods, a day spent swimming in Local River or lake or a beautiful sunset can lift a person’s spirit and give them a new outlook. The aroma of a pure essential oil can do the same.

Flavour and fragrance have now become every day necessities and their demand is constantly increasing across the world. Products from different extraction methods are known under different names even though their basic materials are the same. For instance, orange blossom from citrus aurantium on solvent extraction produces “orange blossom absolute” but that of steam distilled produces “Neroli oil”.

Several products of fruits and vegetables are prepared on commercial and home scale. Products development from fruits and vegetables is the best way to utilize excess produces and save them from post harvest losses..

Value Addition

This is the process of improving the value of a commodity through processing by changing its form, increasing its shelf life or better presentation like packaging. Value addition can be done through the ways.

Fruits, nuts and vegetables play a significant role in human nutrition, especially as sources of vitamins, minerals, dietary fibre, and antioxidants. Increased consumption of a variety of fruits and vegetables on a daily basis is highly recommended because of associated health benefits, which include reduced risk of some forms of cancer, heart disease, stroke, and other chronic diseases. Both quantitative and qualitative losses occur in horticultural commodities between harvest and consumption. Qualitative losses, such as loss in edibility, nutritional quality, caloric value, and consumer acceptability of fresh produce, are much more difficult to assess than are quantitative losses. Quality standards, consumer preferences and purchasing power vary greatly across countries and cultures and these differences influence marketability and the magnitude of postharvest losses. Postharvest losses vary greatly across commodity types, with production areas and the season of production. Losses of fresh fruits and vegetables in developed countries are estimated to range from 2 percent for potatoes to 23 percent for strawberries, with an overall average of 12 percent losses between production and consumption sites. In contrast, the range of produce losses in developing countries varies widely. Losses at the retail, food-service, and consumer levels are estimated at approximately 20 percent in developed countries and about 10 percent in developing countries (Adel A. Kader and Rosa S. Rolle, 2004 ). Overall, about one third of horticultural crops produced are never consumed by humans. Reduction of postharvest losses can increase food availability to the growing world population, decrease the area needed for production, and conserve natural resources. Strategies for loss prevention include use of genotypes that have longer postharvest-life, use of integrated crop management systems and good agricultural practices that result in good keeping quality of the commodity and use of proper postharvest handling practices in order to maintain the quality and safety of fresh produce.

Obesity: A condition characterized by the excessive accumulation and storage of fat in the body. It is a physiological disorder having high body mass index (BMI), which can be expressed as a mathematical formula in which a person’s body weight in kilogram is divided by the square of his or her height in meters.

Objective Methods of quality evaluation: These are based on recognized standard scientific tests to any sample of the product without regard to its previous history. They represent the modern idea in quality control (QC) because the human element has been excluded. This method divided into three groups like physical, chemical and microbiological. The devices are used in this evaluation.

Obligate anaerobes: These microbes do no grow inthe presence of oxygen.

Obligate parasite: Obligate parasites is host specific and grows on living host only and attach limited range of host and are very difficult or impossible to grow on artificial culture/media.

Obligate thermophile: These microorganisms grow at a temperature between 38 80oC.

Oedema / edema: It is an abnormal infiltration and excess accumulation of serous f luid in connective tissue or in a serous cavity. Oedema meanswatery swelling of plant organs or parts. It is also called dropsy.

The potential for significant economic losses from decay caused by postharvest pathogens is greater than is often realized. Harvesting and handling, and the attendant costs for labor and postharvest chemical treatments, can increase the cost of fresh fruits and vegetables several fold from the field to the consumer. Therefore, any produce lost in storage is worth more economically than an equivalent amount lost in the field. Considering economics and the problem of world hunger, it is imperative to understand the importance of postharvest disease and to continually strive to reduce postharvest losses from pathogens. In recent years, many international organizations have identified the necessity of reducing postharvest food losses as an important worldwide goal. While postharvest losses vary from season to season, an average loss of 10% to 30% after harvest is an average estimate. Significantly higher losses are not uncommon in developing countries. The extent of these losses justifies increased research efforts in postharvest pathology (Carl E. Sams, 1994). Chemical treatments and irradiation have effectively reduced the number of microorganisms on various commodities. However, consumer fears associated with chemical residues and the effects of ionizing radiation on fresh produce are forcing the development of alternative protection methods. Also, many pathogens have developed resistance to several commonly used chemicals, while other decaycausing microorganisms currently cannot be controlled by chemicals. Therefore it is better to seek control strategies that will supplement or replace current disease control methods.

Set 1

1. Match the followings:

1. (a & i), (b & ii), (c & iii), (d & vi)
2. (a & ii), (b & i), (c & iv), (d & iii)
3. (a & iii), (b & i), (c & iv), (d & ii)
4. (a & iv), (b & ii), (c & i), (d & iii)

5.1 Introduction

Quality is one of the major positioning tools of the commodity for marketability, profitability and for consumer satisfaction. The relative importance of each quality component depends upon the commodity and its intended use and varies among growers, handlers and consumers. To growers a given commodity must have high yield and good appearance and must withstand long distance transportation to market whereas, appearance of quality and longevity is important from the point of view of wholesale and retail marketers. Terms commonly used in measurement of keeping quality of cut flowers are longevity, shelf-life, vase-life, and lasting quality. In addition to these, several criteria have been used for evaluation of post harvest flower quality like:

Introduction

Fresh fruit journey from the farm to the consumer’s table is an intricate process which needs a lot of attention. The way that the produce is harvested and handled is of supreme importance in relation to its quality shelf life and general market attractiveness. Improper handling practices during these critical stages can bring both quantitative and qualitative loses hence the perishable produce will lose its commercial value and appeal to the consumers (Kader, 2005). No doubt the significance of successful harvesting and post-harvest handling practices is crucial and has an impact on quality features and safety in case of fresh fruits. Poor management can cause physical assault ripening speed and more susceptibility to the growth of micro-organisms which makes the produce unsuitable for consumption or processing.