eChapters

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.
Maturity indices are different for different horticultural crops and are employed to:
1. Ensure sensory quality (flavour, colour, aroma, and texture) and nutritional quality: Harvesting horticultural produce too early (under-developed or immature produce) will result

Stem-borer: Sahyadrassus malabaricus: Hepialidae

Presence of the pest is understood when chewed tissue is seen at at the col­lar region. The mouth of the tunnel in which the borer feeds show pieces of bark, wood and frass particles held together by silk. The saplings break off at the point of injury. When the main stem is attacked, there is mat-like frass at basal region of stem. Larvae girdle main stem and bores downward killing the tree.

Adult moth is peculiar and hangs vertically down by the support of two pairs of legs. Egg period is for 7-10 days, and larvae live for about 10 months inside the larval tunnels. They pupate for 3-5 weeks.

Coriander aphid: Hyadaphis coriandri: Aphididae

Coriander aphids are yellow-green in color, dusted with grayish wax. They have short, dusky, slightly swollen, siphunculi (or cornicles). The Aphids form dense, damaging colonies on leaves, heads, and stems of their host plants.

In its native land, Florida, USA, the life cycle of the coriander aphid is similar to that of other host-alternating aphids. Overwintering eggs occur on other hosts.  A fundatrix (or stem mother) hatches from the egg in the spring. Her offspring are parthenogenetic, and the winged-females are spring migrants. They colonize summer host plants in the family Umbelliferae.

Scale insects:Pseudaulacaspis cockerelli, Parasaisettia nigra:Coccidae

Attack Adults and nymphs feed on plant sap and cause wilting and drying of seedlings and young plants.
 
Brown soft scale: Lecanium sp. (=Coccus) hesperidum : Coccidae

Thrips: Thrips tabaci: Thripidae

The nymphs and adults of the thrips desap from the narrow spaces between the inner leaf axils. Leaves are faded, with curled tips and shining silver streaks or brown spots.  Many minute yellow or white insects are seen moving, generally near the base or middle of leaves and they suck the sap from the plants.  Plants are faded and the yield is reduced.

Leaf-and shoot folders: Hymenia recurvalis : Pyraustidae

Pycnarmon cribrata;Phostria piasusalis

Japanese plum (Prunus salicina) is usually eaten as fresh while as European plum (Prunus domestica) required to process before consumption. Plum ranks next to peach as for as its economic importance is concerned. It is a delicious juicy fruit, prized both for its exquisite fresh fruit flavor and in processing industry. Due to its typical chilling requirement it is grown in cooler region. Two types of plum i.e. Japanese plum and its hybrids and European plum are grown in India.

Papaya (Carica papaya) is a important delicious fruits of herbaceous in nature,. It is most precocious fruit crops cultivated as pure as well as intercropped with mango, guava, peach, and coconut. Papaya starts bearing in 8-10 months after planting.

Bael (Angle marmelos) is an important arid fruits belongs to family Rutaceae and consists 2-3 species of which only one is in cultivation. It is important indigenous fruits of India, drought hardy tree, flowering and fruiting coincides with the onset of monsoon and fruits mature before commencement of summer. The tree shed off entire leaves during hot summer and fruits are exposed to direct sunlight, which favors ripening of fruits.

Xanthan gum: It is a polysaccharide that is produced by fermentation of carbohydrates by a gram-negative bacterium (Xanthomonas campestris) and is a thickening and suspending agent used in pharmaceuticals and prepared foods. It is also called xanthan. Xanthan is a stabilizer produced by Xanthomonas compestris (Plate 671). Xanthan is not hydrolysed or degraded by humans.

Xanthones: It is a group of yellow pigments e.g. mangiferin in mango,

Xanthophyll: Yellow hydroxyl carotene derivative which is present in all green leaves together with chlorophyll and carotene. Xanthophyll is a pigment containing O2 derived from carotene (Plate 672).

Xerophilous: An organism which is thriving in or tolerant to a xeric environment is called xerophilous.

Yabby: It is one of the burrowing Australian crayfishes (Cherax destructor) that are used for food.

Yakitori: A bite-size marinated pieces of beef, seafood, or chicken on skewers is called yakitori.

Yam: It is edible starchy tuberous root of plants (genus Dioscorea of the family Dioscoreaceae) used as a staple food in tropical areas (Plate 676).

Yautia: It is one of the aroid plants (Xanthosoma sagittifolium) chiefly of tropical America with starchy edible shaggy brown tubers that are cooked and eaten like yams or potatoes (Plate 677).

Yearling mutton: Meat obtained from 12-20 month aged sheep. It is also called Earling mutton.

Yeast: Unicellular plant body, very minute in size containing cell wall, cytoplasm with one or more vacuoles and a single nucleus, cause alcoholic fermentation (Plate 678). Yeast usually has little or no mycelium, and reproduces by budding. It results in production of yellowish surface froth or sediment that occurs in saccharine liquids (fruit juices) in which it promotes alcoholic fermentation, consists largely of cells of a fungus (as the saccharomyces, Saccharomyces cerevisiae), and is used in the making of alcoholic liquors and as a leaven in baking.

Sciarid(mushroom flies): Bradysia paupera, Lycoriella auripila: Sciaridae

The larvae feed on the mycelial attachments and restrict the growth of the spawn. The maggots also feed on the developing mushrooms or pinheads and thus cause loss in yield. They also bore the developing mushrooms and render them hollow.

Reducing insecticide application to the lowest level is the motto of IPM in vegetables. Monitoring for the initial build up and timely mechanical removal of the first population is a must in vegetables. Always remove the first affected plants, by diseases like mosaic, and destroy them by burying or burning. Remove insect eggs, insect affected plant parts and adults and immature stages of insects, and destroy them every day. Do not throw them in the field. They will either come back, or pupate and attack later. During nursery stage, use wood ash, cow dung solution, and plant extracts to deter all pests. Use only low residual insecticides like Dichlorvos 1ml/l, Malathion 2ml/l, Endosulfan 2ml/l or Quinalphos 2ml/l, in spots, at the beginning of attack itself.

Q₁₀value: The number of times a reaction rate change with a 10^oC change in temperature is called Q ₁₀value. If reaction rate doubles with 10^oC change in temperature, Q ₁₀= 2. It is also called temperature quotient.

Q-enzyme: It is a branching enzyme responsible for formation of 1-6 bonds in amylopectin.

QHV process: It stands for Quality Has Value Process.

QO₂ : It is a unit for measurement of respiration. Or It is the oxygen uptake in microlitres per milligram on dry weight per hour.

Quailing: In this practice the oranges are kept in the baskets in which they are harvested to allow the fruit to loose little moisture. It is done for a couple of hours before transport to packhouse. This practice would allow the fruit to lose a little moisture which is called quailing. This operation is done for oranges to prevent Oleocellosis.

Qualitative measurement: It is a subjective / objective measurement of the quality of the product for presence of certain compound. It gives the idea of the presence or absence of the particular compound. It deals with the nature of the substance and not its amount or quantity.

Quality: Quality is a measure of the degree of excellence or degree of acceptability by the consumer. The quality may also be defined in term of end use and may vary depending upon consumer’s perception and need. Or quality is the totality of features and characteristics of a product that bear on its ability to satisfy stated or implied needs. It is a term defined by the consumer, buyer, grader, or any other client based on subjective and objective measurements of the food product.

Xanthan gum: It is a polysaccharide that is produced by fermentation of carbohydrates by a gramnegative bacterium (Xanthomonas campestris) and is a thickening and suspending agent used in pharmaceuticals and prepared foods. It is also called xanthan. Xanthan is a stabilizer produced by Xanthomonascompestris(Plate 257). Xanthan is not hydrolysed or degraded by humans.

Yabby: It is one of the burrowing Australian crayfishes (Cherax destructor) that are used for food.

Yakitori: A bite-size marinated pieces of beef, seafood, or chicken on skewers is called yakitori.

Yam: It is edible starchy tuberous root of plants (genus Dioscorea of the family Dioscoreaceae) used as a staple food in tropical areas.

Yautia: It is one of the aroid plants (Xanthosoma sagittifolium) chiefly of tropical America with starchy edible shaggy brown tubers that are cooked and eaten like yams or potatoes.

Yearling mutton: Meat obtained from 12-20 month aged sheep. It is also called Earling mutton.

Yeast: Unicellular plant body, very minute in size containing cell wall, cytoplasm with one or more vacuoles and a single nucleus, cause alcoholic fermentation (Plate 258). Yeast usually has little or no mycelium, and reproduces by budding. It results in production of yellowish surface froth or sediment that occurs in saccharine liquids (fruit juices) in which it promotes alcoholic fermentation, consists largely of cells of a fungus (as the saccharomyces, Saccharomyces cerevisiae), and is used in the making of alcoholic liquors and as a leaven in baking.

Apricot is commonly known as Armenian plum. Its scientific name Prunus armeniaca derives from the assumption that apricot was known in Armenia during ancient times and has been cultivated there for so long that it is often thought to be native of that place. The cultivated apricot has its origin in North-Eastern China, whereas wild apricot, popularly known as ‘Zardalu’, appears to be indigenous to India. Generally, there are two types of apricot, namely, sweet kernel type and bitter kernel type.

Bael is commonly known as Bengal quince, Indian quince, golden apple, holy fruit, stone apple and bel. It is more prized for its medicinal virtues than its edible quality.  The deciduous tree with trifoliate aromatic leaves is traditionally used as sacred offering to ‘Lord Shiva’. Fruit is a hard-shelled berry and very well-known for its medicinal properties due to marmelosin content. The ripe fruit is tonic, restorative, laxative and good for heart and brain. The pulp is often processed as nectar or squash. A popular drink called “Sherbet” in India is made by beating the seeded pulp together with milk and sugar. A beverage is also made by combining bael fruit pulp with that of tamarind. These drinks are consumed perhaps less as food or refreshment than for their medicinal effects. For medicinal use, the young fruits, while still tender, are commonly sliced horizontally and sun-dried and sold in local markets. The fruit, roots and leaves have antibiotic activity. The root, leaves and bark are used in treating snakebites.

Ber is most commonly found in the tropical and sub-tropical regions of the world. Originally native to India, it is now widely naturalized in tropical region from Africa to Afghanistan, China, Malaysia, Australia and in some Pacific regions. The major production regions for Indian jujube are the arid and semi arid regions of India. It is also known as ‘King of Arid Fruits’ and ‘Poor Man’s Fruit’. In Philippines it is called manzana or manzanita (“apple” or “little apple”). Fully ripe fruits are less crisp and somewhat mealy; overripe fruits are wrinkled, the flesh buff-coloured, soft, spongy and musky. 

The breadfruit is believed to be native to New Guinea. It is grown throughout the tropics. Breadfruit is a staple food in many tropical regions. Raw breadfruit has a very light fragrant taste that is somewhat like a guava, but not as sweet. The texture of raw breadfruit is rather tough and rubbery. It is used more as a vegetable than as a fruit. It can be eaten ripe as a fruit or under-ripe as a vegetable. Soft or overripe breadfruit is best for making chips and biscuits. The dried fruit can be made into flour. Its flour is much richer than wheat flour in lysine and other essential amino acids. Breadfruit is high in calories and contains a good amount of vitamin C and potassium with smaller amounts of calcium, iron and magnesium. The wood is yellowish or yellow grey with dark markings or orange speckles; light in weight; not very hard but strong, elastic and termite resistant and is used for construction and furniture. Fiber from the bark is highly durable and is used for clothing in Malaysia.