eChapters

53.1. Aim

To conduct practical on freezing of vegetables

53.2. Theory

Freezing is often considered the simplest and most natural way of preservation for vegetables. Frozen vegetables and potatoes form a significant proportion of the market in terms of frozen food consumption. The quality of frozen vegetables depends on the quality of fresh products, since freezing does not improve product quality. Pre-process handling, from the time vegetables are picked until ready to eat, is the important factor affecting quality of finished product. The process variables for freezing of different vegetables and flow chart are shown in Table 54.1 and Fig 54.1. Generally fruits after preliminary treatments are packed in sugar syrup and frozen in freezer.

INTRODUCTION

Preservation of food by drying or chemical means as by alcohol or acid fermentation and that by the use of ice is long recorded in history. With the advancement of science and the knowledge governing various unit operations in food processing, these food preservation techniques employing thermal, radiation, or low temperature or a combination of these have only got further refined as regards their viability and commercial applications. Process foods of different genre and cuisine, which include frozen foods too, are increasingly becoming popular the world over for reasons of quality, safety and year round supply of nutritious foods to cater to different niche segments of human society. Increasing health consciousness is buoying those processed foods which are preserved and stabilized using non-thermal technologies as these ensure retention of food nutrients to a better definition. Interest in frozen food also stems from need to deliver safe and nutritious foods with extended shelf-lives.

1. Introduction

Freezing is a method of food preservation that involves lowering the temperature below the freezing point of food generally -18 °C or below. During freezing of food the water present in them changes its state to form ice crystals. Human beings in the colder regions have used freezing as a means of preservation since they learnt hunting and gathering foods. The foundation of the modern frozen industry was laid in mid 1920 when Clarence Frank Birdseye, an American inventor used cold brine solution to chill packaged fish and extended it further for quick freezing of meat poultry fruit and vegetables. 

Freezing is one of the easiest and least time consuming methods of food preservation. The freezing process is a combination of the beneficial effects of low temperatures at which microorganisms cannot grow, chemical reactions are reduced, and cellular metabolic reactions are delayed.

Methods of Freezing

1. Sharp freezing (slew freezing)

In sharp freezing commodities are exposed at -15 to -29⁰C. It required 3-72 hrs. Here the thawed tissue cannot regain its original water content. The ice crystals formed are large and rupture the cells. The thawed tissue cannot regain its original H₂O content.

The cotton aphid :Aphis gossypii: Aphididae

Both nymphs and adults cause the damage by sucking the plant sap from shoot tips, flowers and leaves.  Severe infestation may result in complete drying of affected parts.  Attacked leaves curl up, wither and fall. These are yellowish green or brown coloured aphids.  The total life cycle from first instar nymph to adult occupies an average of 8-10days.  It reproduces parthenogenetically and viviparously.  The female may produce 10-30 young ones in a life span of 10-12 days.  The nymphs transform into adult in 5-8 days after passing through four moults.

Botany: French bean has tap root system with poor nodule formation. Leaves are trifoliate. Though a self-pollinated crop, French bean offers wide variability for plant growth (bushy / climbing), colour of pod (green / waxy coloured), cross section of pod (flat / oval / round), pliability (stringed / string less) etc.

Varieties

1. Arkakomal: Plant is bushy. 70 days for flowering.
2. Blue pod medium: It is a white seed variety. It has bluish black spots on pods.
3. Bountiful: Introduction from US comes up in September to February. Seeds are Brown sweetish. It is resistant to common disease.
4. Contender: Tolerant to powdery mildew and mosaic.
5. Pant anupama: Developed from pantnagar. Bushytype
6. Pusaparvathi: Developed by X ray radiation of American variety IARI

Among beans, the most popular bean is French bean and it has wider distribution and larger gene pool. Various names are associated with cultivars viz., Snap bean, salad bean and green bean and all these names associated are with beans of vegetable types. The names haricot bean, dry bean and navy bean are applicable to pulse types. String bean, dwarf bean and pole bean applicable to growth forms. It is known as Rajmah in Hindi, Tingalawari in Kannada and Fras bean in Punjabi. Cultivars preferred for Canning, frozen and freeze-dried are having round pods. Fresh market cultivars are flat or oval shaped. Yellow pod cultivars are also grown. Generally fresh market cultivar yields higher in temperate region than in tropical region. Beans are said to be antidiabetic and good for bladder burns, cardiac, carminative, diuretic.

Origin and Distribution: Phaseolus vulgaris was domesticated in Central America about 7000 years ago and it is also thought to be domesticated in Brazil and Northern Islands and was introduced to Europe in 16th century. Vavilov (1951) reported that Phaseolus vulgaris originated in South Mexico and Central American centre of origin. The first cultivar has been selected in Peru. From Peru it spread to Europe and to Asia. Wild species P. aboriginus in North West Argentina is considered as the wild progenitor of French bean. Based on growth habit, crop can be classified into pole type, semi pole type and bush type. Former varieties are more string types. American origin of P. vulgaris is questioned by De Candolle (1584). Southern part of Mexico and Central America are considered to be primary centre of origin. While secondary centre lies in Peru-Bolivian-Ecuador of South American continent. In Europe, French bean spread rapidly in 16th and 17th centuries and reached England by 1594. From Europe, it was introduced to India during 17th century (Simmonds, 1976).

Among the pulses, rajmash is one of the high potential pulse crops with a yielding potential of 18 to 20 q per ha. Rajmash or French bean (Phaseolus vulgaris L.) is a short duration non–traditional grain legume and one of the precious and highly relished pulse crops of North India. Rajmash is known by various names viz., French bean, rajma, haricot bean, field bean, kidney bean, snap bean, pole bean etc. It is an important winter vegetable grown both for tender pods and dry seeds, which form a rich source of crude protein (21.25%), fat (1.7%) and carbohydrates (70%). Besides, it contains 0.16 mg iron, 1.76 mg calcium and 3.43 mg zinc per 100 g of edible part (Jasvinder Kaur and Mehta, 1994). The fresh pods and green leaves are used as vegetable. The antimetabolites of dry beans needs removal by cooking and soaking in water.

French bean (Phaseolus vulgaris L.) is a nutritious protein-rich legume vegetable crop cultivated in all parts of the world except Antarctica. Immature pods are consumed as vegetables, and matured pods are used as grain legumes (Allem, 2013). French bean is cultivated in 1.65 million hectares of area with a production of 26.98 million tonnes and productivity of 16.36 tonnes per hectare for vegetable purposes. As a grain legume, French bean was cultivated in 33.02 million hectares with a production of 28.90 million tonnes and productivity of 874.1 kg/ha during 2019 globally. In India, French bean is grown in 2.56 lakh hectares for vegetable purposes and 126.91 lakh hectares for grain legume purposes with a production of 7.26 lakh tonnes as immature pods and 53.10 lakh tonnes of grain legumes with a productivity of 2.83 t/ha of green pods and 418.4 kg/ha as grain legumes (area, production and productivity of livestock, Food and Agriculture Organization of United Nations, 2020). However, the area, production and productivity statistics of beans in FAO statistics may also include other beans such as mung bean and others (Sharma et al., 2013). French bean is also known by other names such as common bean, kidney bean, dwarf bean, haricot bean, string bean and garden bean. In India, French bean is also known by different names as Frash bean and Rajmah in Hindi, Shravanghevada in Marathi, Thingalaware in Kannada and Fras bean in Punjab.

French bean, Phaseolus vulgaris under the family Fabaceae (Leguminosae) and having chromosome No.2n = 2x = 22 is an important leguminous vegetable crop grown worldwide for its tender fruit (pod) as vegetable and dry seeds as pulse. French beans are unique among plant foods due to their high protein content. It is a highly variable species that has a long history of cultivation. Most of the bean varieties for processing (canned, frozen, and freeze-dried) are round podded, while fresh market cultivars are often flat or oval shaped. French bean is a valuable source of the amino acids lysine and tryptophan; minerals likes, iron, copper and zinc; and beneficial phytochemicals, antioxidants and flavonoids.
Origin, domestication and adaptation in India
French bean is thought to have been originated in South and Central America. Southern Mexico and Central America are considered to be the primary centre of origin, while secondary centres lies in Peru-Bolivia-Ecuador region of American continent. It was actually domesticated in Mesoamerica first and travelled south, probably along with squash (Cucurbita species) and maize. Multi-locus sequence data have indicated that the domestication of common bean was initiated 8000 years ago. Cultivation of French beans started by the American Indian tribes settled in Tehuacan Valley of Mexico and in Callejon de Huaylas, Peru. When Christopher Columbus returned from his second voyage to the New World in the year 1493 he brought French beans with him in the Mediterranean region. French beans were considered to be rare to find and expensive but soon became one of the commonly used beans in the 19th century. In France, French beans were introduced in the year 1597 by the Conquistador (Spanish explorers). In Europe, the French bean spread rapidly in the 16th and 17th centuries and reached England by 1594.

The frequency distribution of the populations of M₂ and M₃ generation for each genotype was extracted according to Panse and Sukhatme (1961). Skewness and Kurtosis for all the characters were calculated as per the standard method. Skewness refers to the symmetry of the frequency distribution. A measure of skewness is obtained as making use of the second and their moments about the mean. It is defined as,

Frequency distribution table is a statistical table which shows the sets of all distinct values of the variables arranged in order of their magnitude either individually or in groups with their corresponding frequencies side by side.

Need for frequency distribution table

1. To condense the data
2. To provides quick reference for the entire data
3. To facilitate quick & easy statistical analysis of data
4. To reveal the pattern within the data

10.1 Introduction

There are very few frequency modulated fiber optic sensors. This is because frequency modulation of light occurs under a limited range of physical conditions. The principal one is based on Doppler effect. There are few other circumstances under which the frequency of light is modulated. These include luminescence and Raman scattering. Luminescence has been included in chapter 7under fluorescence based sensors. In this chapter we shall focus on the sensors based on Doppler effect and Raman scattering. In particular, we shall discuss the measurement of blood flow velocity, colloidal particle motion and Raman spectrum using optical fibers.

1. What are Primary produce?

Primary produce, also known as primary products, refers to raw materials or natural resources that are derived from agriculture, forestry, fishing, or mining activities. These products are typically unprocessed or minimally processed, and are often used as inputs in further manufacturing or production processes. Examples of primary produce include crops such as wheat, corn, and soybeans, as well as livestock such as cattle, sheep, and pigs. Forestry products such as timber and paper pulp, as well as fish and other seafood harvested from the ocean or inland waterways, are also considered primary produce.

1. Choose the most appropriate option with a tick mark

i) Floating plants are required for breeding

a) Guppies

b) Angel fish

c) Swordtail

d) Gourami

ii) Breeding traps are generally used for

a) Egg-scatters

b) Egg-depositors

c) Livebearers

d) Nest-builders

1. A production of 600 tones/ha/year of tilapia in cages has been recorded in Laguna Bay in Philippines.

2. Indian Major Carps (IMC) contributes 84% of India’s aquaculture production.

3. The seed production of the carps has been standardized, with commercial hatcheries producing over 19000 million fry per year.

4. A pit like structure located near the outlet of the pond is called as harvesting pit (measures about 50 - 100m2).

5. Size of the nursery pond = 12 x 6 x 1m.

6. Size of the Rearing pond = 25 x 12 x 1m.

7. Size of the production pond is 0.1 to 2 ha.

8. Size of the quarantine pond is less than 0.5 ha.

9. During construction to retard erosion and seepage, soil must contain a minimum of 25% of clay.

10. The depth of the pond must be 0.5 to 1m.

Introduction

The science of Biotechnology has been making every effort to create new opportunities for the welfare of humanity. Modern biotechnological tools are applied in India to boost fish production through aquaculture as well as conservation of the vast aquatic resources of the country for sustainable utilization. Transgenic technology is widely used in biotechnology, from the generation of genetically modified (GM) foods to the production of pharmaceutical proteins. This technology has been successfully used to develop fast growing super-fish stocks for aquaculture. The main reasons for genetic manipulation of species used in aquaculture are to enhance the growth and efficiency of food conservation, to increase tolerance to environmental variables like temperature and salinity, to produce new colour variants of ornamental fishes, to increase the resistance of species to pathogens, etc. Though the conventional selective breeding approach has proven to genetically upgrade rohu19, it is a rather time consuming process. Traditional selective breeding approaches in combination with transgenesis can bring about faster improvement of selected traits.

Introduction

Culture of aquatic organisms is a significant economic endeavor that benefits millions of people worldwide by generating employment opportunities and ensuring food security. One of the lucrative aquaculture ventures in many countries is the cultivation of freshwater pearls. Prior to the development of cultured pearl farming, pearls were harvested from the Gulf of Mannar, the region between India and Sri Lanka, the Bay of Bengal, the Egyptian coast (Red Sea), and the Persian Gulf (Saudi Arabian coast) (Matlins 2001; Strack 2008), which benefited the nation’s economy. However, the natural pearl fisheries have been depleted as a result of indiscriminate fishing, habitat destruction, and pollution. Realizing its economic significance, pearl farming has developed into a successful aquaculture activity to support the nation’s aqua-economy through innovation and standardization of farming techniques.

Pearls are cultured in both marine and freshwater environments, and they are particularly created in bivalves with an inner nacreous layer. Many countries like China, Japan, Australia, Indonesia, French Polynesia, Cook Islands, Philippines, India, Sri Lanka, Bangladesh, Myanmar, Thailand, Malaysia and Mexico are major pearl producing countries through farming (Gervis and Sims 1992; Southgate 2007; Southgate et al. 2008 & Saurabh et al. 2021). In addition to the economic benefit like other bivalves these pearl producing mussels has positive environmental impact and also has several nutritional benefits. Freshwater bivalves including these pearl mussels are widely used in aquaculture for aquaculture-effluent treatment of aquaculture farms. The shells of bivalves are the source of two highly versatile chemical compounds, calcium carbonate or calcium oxide which is having wide industrial applications. The shells are used in cosmetics and traditional medicine, handicraft and jewelry. These economic and environmental benefits have catalyzed expansion of the bivalve aquaculture industry in various regions of world. During 2009 to 2018 the average freshwater pear cultured production was 1928 tonne while China continued to dominate world freshwater pearl culture (FAO, 2020). However, the freshwater pearl culture production has declined from 3321 tonne in 2009 to 703 tonne in 2018. This drastic decline may be due to overexploitation, habitat degradation, pollution, lack of proper management and many more and it has threatened long term sustainability of fisheries and this farming sector. It gives an alarming call for all fisheries managers and policy makers to formulate management measures to implement for the betterment of the sector. Though this farming technology has a great potential to increase the aqua economy of the country, growth should be sustainable.

Introduction

Pearls have been favourite jewel of humanbeing since ancient times. Pearl is a natural gem and is produced by living organisms, the pearl oysters and mussels (Molluscs), unlike other precious stones. It is perhaps, the only gem that does not require the treatment by lapidary. According to our Indian system of gemmology, of the nine maharatnas (Heera, Mukta, Manikya, Pravala/Munga, Gomeda, Indra-neela, Vaidurya, Pushyaraga, and Panna) pearl (Mukta) is only next to diamond (Heera). The science of pearl culture has not been widely popular, however, the art and trade form has reached the zenith.

With the turn of the last century, the demand for pearls increased, but their supplies from the existing fishing grounds have diminished due to overexploitation and pollution. Such a situation necessitated tremendous research attention in the following decades with support from state and trade sectors, the world over. This led to the evolution of culture pearl technology as a booming aquaculture enterprise in Japan and China. These two countries have a monopolistic control over pearl trade.