eChapters

49.1. Aim

To perform practical on drying/dehydration of different vegetables.

49.2. Theory

Drying refers to the method of removal of moisture content from the food to a level at which the activities of food spoilage and food poisoning micro-organism are inhibited. Therefore, reduction in water activity of the food is the main principal of preservation by drying. In the dehydrator initial temperature is generally kept at 43oC which is then gradually increased to 60-66oC for vegetables. The product shall be prepared from wholesome vegetables free from blight, insect infestation and fungal discoloration. Only edible portion of the vegetables shall be used and it shall be free from stalks, peels, stems, and extraneous matter. The dried/dehydrated vegetable may contain permitted preservative. The finished product shall be of good edible quality and shall reasonably reconstitute to its original shape and quality on boiling for 15 minutes to an hour. The finished product shall be free from visible mould, insect or larvae. Kind of dry vegetable shall be declared on the label. Acid insoluble ash shall not be more than 0.5%.

50.1. Aim

To prepare products from tomato fruits.

50.2. Theory

Commercial products from tomatoes include juice, puree and paste. Processing of tomato is now practiced from home scale level to a large scale enterprise. As a semi finished product, tomato puree is prepared on a small scale while at large scale tomato paste has gained commercial significance. Both puree and paste are used for preparation of different finished products like ketchup, juice, soup etc. The method for preparation of these products are well standardized, however, some modification with respect to recipes are made in the processing plants owing to variation in the quality of the raw material. The method for preparation and recipe of different tomato products are as under:

50.3. Raw material, ingredients and utensils required

1. Tomatoes.

2. Stainless steel knives, utensils, juicer, pulper, glass bottles, corking machine, crown corks, muslin cloth, boiler/gas bhatti, etc.

51.1. Aim

To prepare products from tomato fruits.

51.2. Theory

Commercial products from tomatoes include ketchup, soup, cocktail, chutney, canned and dehydrated tomatoes. Processing of tomato is now practiced from home scale level to a large scale enterprise. Both puree and paste are used for preparation of different finished products like ketchup, canned and dehydrated products, soup etc. The method for preparation of these products are well standardized, however, some modification with respect to recipes are made in the processing plants owing to variation in the quality of the raw material. The method for preparation and recipe of different tomato products are as under:

51.3. Raw material, ingredients and utensils required

1. Tomatoes, sugar, salt, sodium benzoate etc.

2. Stainless steel knives, utensils, juicer, pulper, glass bottles, corking machine, crown corks, muslin cloth, boiler/gas bhatti, etc.

52.1. Aim

To conduct practical on freezing of fruits.

52.2. Theory

Freezing is a method of preservation in which the food temperature is reduced below freezing point and a proportion of water changes in to ice-crystals. Immobilization of water to ice and the resulting concentration of dissolved solutes in unfrozen water cause lowering of water activity in the food. Thus, reduction in water activity and use of low temperature coupled with some pre-treatments is the basis for food preservation by freezing. The method for freezing of fruits depends upon the intended use. The process variables for freezing of different fruits and flow chart are shown in Table 52.1 and Fig 52.1. Generally fruits after preliminary treatments are packed in sugar syrup and frozen in freezer. The fruits are frozen to an internal temperature of -18oC or lower and kept at 18oC or lower throughout transport and storage.

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.

54.1. Aim

To determine crude fibre in given samples.

54.2. Theory

Fibres can be classified into four categories like crude fibre (cellulose); acid detergent fibre (cellulose + lignin); neutral detergent fibre (cellulose + lignin + hemicelluloses) and total dietary fibre (Cellulose + lignin + hemicelluloses + pectic substances). Crude fibre is the organic residue of a sample. A fat free sample is treated with boiling sulphuric acid and subsequently with sodium hydroxide. The residue after subtraction of ash is regarded as crude fibre.

54.3. Reagents/ Apparatus/Glassware

1. 0.255 N Sulphuric acid solution

2. 0.313 N Sodium hydroxide solution

3. 10% Potassium sulphate solution

4. Ethanol

55.1. Aim

To determine dietary fibres in given samples.

55.2. Theory

Fibres can be classified into four categories like crude fibre (cellulose); acid detergent fibre (cellulose + lignin); neutral detergent fibre (cellulose + lignin + hemicelluloses) and total dietary fibre.

55.3. Procedure for estimation of dietary fibre

55.3.1. Acid detergent fibre (ADF)

Reagents: Cetyl tri-methyl ammonium bromide (CTAB) reagent and Acetone

Apparatus: Digestion apparatus vacuum pump, oven, desiccator and sintered glass crucible.

56.1. Aim

To determine quality characteristics of dried and dehydrated fruits and vegetables.

56.2. Theory

The quality of dried/dehydrated products can be measured by estimating moisture contents, preservatives level, acid insoluble ash contents and most importantly enzyme reactions.

56.3. Estimation of Acid insoluble ash

1. To total ash add 25 ml of dilute HCl (10% w/w)

2. Cover with a watch glass and boil gently over a low flame for 5 minutes

3. Filter and wash the filter paper thoroughly with hot water

4. Return the paper to the original dish, ignite, cool and weigh the insoluble ash

Loose smut of wheat occurs worldwide but is more abundant and serious in humid and sub – humid regions. In India, this disease is found in all wheat growing areas but the incidence is generally more in comparatively cooler and moist parts of north India than south India. The yield loss may go up to 30% due to this disease.

The disease was fi rst reported in Java in 1893 and is prevalent in all sugarcane growing countries. In India the disease occurs in an epiphytotic form in Uttar Pradesh and Bihar during 1939-1940 and 1946-1947 and cause severe damage that threatened the existence of sugar industries.

The plants wilt at the time of grain fi lling stage. A light brown water soaked area is seen at the stem base. Sclerotia can be seen on the outer region of stalk when the plants get older. White mycelial growth with large sclerotial bodies is seen over the stem pith. The stem often breaks down at the point of infection.

The initial symptom of Alternaria brassiciola appears as small, dark colored spots which enlarge rapidly to form circular lesions. Under humid conditions a bluish velvety fungal growth is seen in the centre of these spots. Spots caused by Alternaria brassicae are almost similar to those produce by Alternaria brassicicola but are comparatively smaller and lighter in colour. When many spots are formed on the leaves, the leaves turn yellow and dry prematurely. Formation of pods and seeds are adversely affected.

All the above ground parts of the plant are affected. There is development of round and elongated spots surrounded by brownish red margin on the leafl ets. At later stage spots coalesce and entire leaf turns brown. On green pods, the lesions are usually circular with dark margin and pin head like dark dots representing the pycnidia in concentric circles.

Wilt appears in the fi eld as patches is both seedling stage and developed plants. Symptoms include drooping and wilting of uppermost leaves. Plants become completely yellow and die. Plants are affected during the pod fi lling stages, seeds are often shrivelled. There will be rotting at the basal portion of the plant. Discoloration of vascular bundle are noticed when the stem is spitted
open.

The disease i s seen at all crop growing stages. The fi rst symptoms appear at the time of emergence of seedlings, when the cotyledons are attacked. They become yellow and turn brown followed by wilting and drying of the affected seedlings. In the fi eld, the wilting symptoms appear in patches. First of all, the older leaves become yellow, loose their turgidity, wilt, turn brown and droop.

The disease is seen at 3-4 leaves stage. Scattered, irregular, yellowish patches appear on the upper surface of the leaves and stipules. On the corresponding under surface of these patches, a greyish violet fi ne cottony mildew growth is seen. Infected tissue soon dies and turns brown. The disease fi rst appears on lower leaves and later spreads to upper leaves.

Disease appears later part of the crop season mostly during blossoming period. The first sign of the disease is the appearance of small brown patches on the leaves mostly on basal leaves which starts from tip or margin of leaves and spread downwards or inward directions.

It is a very common disease found in all the onion and garlic growing areas. It mostly attacks the bulb as well as the seed crop. The infection or severity of the disease is more in Kharif crop causing 60% yield loss.

It is a very important and commonly found disease of chili which observed in field as well as in storage. It is also known as anthracnose disease which is mostly seen in tropical and sub tropical regions.

It is a very common disease of mango. It is otherwise known as blossom blight, leaf spot, twig blight or wither tip.

Citrus crop includes lime, lemon, sweet orange, mandarin orange, Kamala orange, grapefruit, malta and pomelo etc. The disease which attacks one species of citrus mostly attacks other species also.

The disease attacks all the growth stages of plant affecting all above-ground parts. Plant covered with powdery patches leads to distortion, malformation and discolouration of leaves especially young leaves. Powdery patches gradually turn to grey and fi nally dark colour. Affected fl ower fails to develop fruit. Young berries turn black, irregular in shape and develop cracks. Sometimes berries ripe partially and rot. Vines get wilted.

It is a serious disease of apple which not only reduces the quality and size of fruit but also cause premature fruit drop and defoliation. Fruit loses its marketability due to poor quality. It also reduces storage time and cause loss up to 70%.

The fi rst symptom of disease appears in early spring soon after leaves come out of buds. Affected leaves become distorted and fold over as tips directed backwards. The whole lamina puckered except tip and blistered. In some leaves, part of leaf show distortion. Blistered portions are thicker, softer than the normal leaf blade. The affected areas remain green for a while and gradually become yellow and fi nally turn reddish-purple in colour. 

It is known by different names such as Ramularia leaf spot, rust, bird’s eye spot, grey spots, and white spot. It mostly attacks leaves but can also attack fruit stalks and also fruits.

The symptom appears as numerous, circular, light yellow to dark yellow spots on both the surfaces of leaves but is more prominent on the upper surface. The spot may coalesce to form large, irregular patches and soon entire leaf turns yellow and dries. Affected leaves appear as reddish-brown in colour. Excessive spotting destroys green tissues and becomes weak and yield reduced drastically

The disease appears as tumour like swelling or galls on leaf veins, leaf stalks, peduncles, stems and on fruits. The galls on the vein give a swollen and hanging appearance to the leaves. These are elongated, looks glossy in beginning but later rupture to become rough and corky. When stems remain succulent, numerous tumours may form on them. In severe case, the plant may kill prematurely.

All varieties of rose are susceptible to this disease. It is an important disease of rose which causes a sharp reduction in number and size of fl owers.

India had fourfold increase in population from 0.3 billion to 1.34 billion and registered a fivefold increase in food grain production from 50 million tons to
285 million tons in 2018 (Paroda, 2020). 

1. Seed is the key ingredient in establishment and expansion, diversification and improvement of crops/and crop husbandry.

2. Seed is the most effective and efficient means of crop propagation.

Genetic purity is the vital determinant in continuing the genetic integrity in seed from generation to generation. This is the basis of variety purity maintenance. The genetic purity depends upon the purity of the seeds planted. The genetic purity of the seeds planted must exceed or equal to the final product purity standards required as the purity generally decreases with subsequent generations of propagation. The improved varieties loose their identity and healthiness unless properly maintained. Maintenance selection can prevent the seed quality deterioration.

Clonal crops belong to at least 34 families including herbs, shrubs, trees and vines. Clonal crop improvement dates back to 10,000 years ago. The diversity of clonal crops and their wild relatives are very significant but not yet fully understood and exploited. Many crops represent combination of sexual and clonal reproduction. Different parts of the clonal crops which may or may not be the same as consumed parts have been shaped as clonal propagules such as stem, setts, tuber, rhizome, corms and bulbs among others.

Micrografting is a method to produce virus free, viroid free and disease free grafts that are clonally propagated. This method is an aid to mass multiplication. In vitro grafting is applied to difficult to root clones. Micrografting is performed to understand incompatibility prediction between the two grafting partners, virus indexing, deduction of latent virus, safe germplasm exchange and to do grafting functions throughout the year. It is not season specific. Protocols for micrografting are available for almond, pistachia, olive, prunus, grape, mulberry, cashew, citrus, peach, pear, avocado, hazlenut, walnut, chestnut and grape fruit (Hussein et al., 2014).

In vitro cloning is a vegetative propagation performed in the Plant Tissue Culture system. In vitro micropropagation cloning propagation is mostly applied to the vegetatively propagated plants and in particular in ornamental, fruit and in a few orchard crops and in vegetable crops besides in many forest tree species.

Organically produced seeds are obtained by adapting the organic crop production system. Organic seed is a critical input but specialised efforts to produce organic seeds are not adequately and systematically followed. Accredited organic farming standards recognises the organic seed production as a prerequisite to organic farming. Seed health is important in organic seeds since seeds are not treated with chemical fungicides.

Synthetic seeds are also known as somatic seeds, artificial seeds, clonal seeds and synseeds. They are analogue for botanical seeds. Somatic embryoids which are tissue culture produced embyoids with bipolar structures, apical and basal meristematic regions which are capable of forming shoot and root respectively. Somatic embryoids are encapsulated and are used as artificial seeds possessing the ability to convert into plants in in vitro and ex vitro conditions. Artificial seeds are broadly two types.

Crop improvement is a continuous process. Crop improvement aims to genetically enhance, enrich and empower the crop plants with superior performance, enhanced yield level, higher quality of food, nutritional, fodder, energy produce and adaptability to climate change and crop growing environments. The intrinsic virtues of the improved cultivars could be sustained mainly through the production of the quality assured seeds endowed with genetic capabilities. The quality assured seed delivery system is through the seed chain from the basic seeds through Nucleus-Breeder-Foundation-Certified seed. Quality seed production system need to be based on genetic, breeding and seed technological protocols including field and laboratory testing to ensure very high genetic purity, true to type and superiority.

Deterioration of Crop varieties in their genetic endowments/qualities has been explained by Kadam (1942). Publication on maintenance and management of breeder seed production (Laverack 1991), and maintennce of self pollinated crop varieies (De Hanns 1953; Parlevliet 2007) explain in detail various aspects in maintenance of the seed quality.

Molecular markers may be a short DNA sequence that flanks base pairs like SNP, a Single Nucleotude Polymorphism, small fragment or SSR Single Sequence Repeat or an extended site as in the case of microsatellites. Schematic representation of the SSR assay is shown in Fig. 1. Genetic markers have to be easily identified, linked to a specific locus and polymorphic. Molecular markers are subdivided into codominant monolocus and polyallelic markers and the second group contains dominant, polyallelic and biallelic markers. 

Leaves are alternate in distichous arrangement; lamina long and linear and leaf sheath covering the internodes; ligule membranous and auricle claw shaped. The inflorescence is a spike and florets are borne on rachis node. Each spikelet has three florets. In two row barely, lateral spikelets become sterile.

Agathi is a fast growing tree upto 10m. tall. Branching is drooping. The stem bark is deeply furrowing forming cork like plates. Leaves are compound, pinnae, 20 to 30 cm. long glabresence to pubescent. Leaflet oblong rounded 18 to 24 pairs of leaflets that are green to dark green mostly, bitter free. Inflorescence is a raceme 4 to 7 cm long and bearing 2 to 5 flowers that are white, red, yellowish and pink. Flowers are 5 to 10 cm long, 3cm wide, curved calyx bell shaped 2 cm long, 2 lobed, fine teeth like serration, fleshy. 

Conservation of released varieties requires a sound scientific and technical basis. There are two main strategies for conserving agricultural biodiversity, namely ex-situ and in-situ conservation, both of which are equally important. In-situ conservation refers to the maintenance of a species in its natural habitat. Exsitu conservation is the conservation of components of biodiversity outside their natural habitats. It is conserved in the form of seeds (seed gene bank), live plants (field gene bank), tissues (tissue gene bank), pollens (pollen gene bank) and DNA materials (DNA bank). 

In order to provide for the establishment of an effective system for protection of plant varieties, the rights of farmers and plant breeders and to encourage the development of new varieties of plants it has been considered necessary to recognize and protect the rights of the farmers in respect of their contribution made at any time in conserving, improving and making available plant genetic resources for the development of the new plant varieties. Moreover to accelerate agricultural development, it is necessary to protect plants breeders’ rights to stimulate investment for research and development for the development of new plant varieties.

‘Hydroponics’ technique was first developed on commercial scale as early as in 1930 by

A. De. Condole             B. J.D. Hooker

C. W.F. Greicke            D. Hugo De Vries

The response of a plant to the relative length of day and night is called as

A. Photosynthesis      B. Phytochrome

C. Photoperiodism     D. Photo respiration

Plant propagation by means of seed is called ________ propagation.

A. Sexual          B. Parthenocarpy

C. Asexual        D. Apomixis

Organic soils contain _____ % or more of organic matter.

A. 10       B. 15

C. 20      D. 30

The practice of smoking the trees to induce off-season crops in mango is

A. Smudging      B. Bending

C. Ringing         D. Notching

India ranks ___________ in area and production of vegetables in the world.

A. First           B. Second

C. Third         D. Fourth

The scientific horticulture consists of the following divisions. Among them, which division has impact on environment aesthetically and functionally

A. Fruits         B. Flowers

C. Spices       D. Plantations