AE 3201 Postharvest Technology PDF

AE 3201 Postharvest Technology  Main Ref. & Textbooks Ø Postharvest Technology of horticultural crops, Edt. A A Kader, University of California, 2002 Ø Tropical products Transport handbook, Edt. B M McGregor, USDA Publication, 1987 Ø The commercial storage of fruits, vegetables, and Flor...

AE 3201 Postharvest Technology  Main Ref. & Textbooks Ø Postharvest Technology of horticultural crops, Edt. A A Kader, University of California, 2002 Ø Tropical products Transport handbook, Edt. B M McGregor, USDA Publication, 1987 Ø The commercial storage of fruits, vegetables, and Florist and nursery stocks. Edt. R E Hardenburg, USDA Publication, 1990 Ø Agricultural Process Engineering, S M Henderson & R L Perry, USA, 1966. Ø Produce Handling Packaging and Distribution, K Peleg, 1985 AVI Publishing Company, Westport, Connecticut + Number of latest research publications What is “Postharvest Technology”? Interdisciplinary science and techniques which is applied to agricultural produce after harvest for protection, conservation, processing, packaging, distribution, marketing, and utilization Pre-harvest Agricultural (Plant/Animal) produce Perishables Semi-Perishables Durables  Durables Can be kept for a long period of time Low moisture content Low respiration rate SL Climate? MC – ? % Ex: Cereals, Pulses, Oil seeds, Sugar, Spices and condiments, Plantation Products (cashew nuts, copra, tea, coffee, cocoa) Perishables Die very fast (very short shelf life) Higher moisture content Higher respiration rate MC – 75 or above ? % Ex: Some Fruits and vegetables, milk and milk products, Meat, Fish and Egg Water Activity ? Semi-perishables Properties in between Ex: Potato, Onion, Sweet potato, Yams and Cassava Think about these; - Storage - Environmental Conditions - RH, Temperature (higher / lower) - Water gain (cereals) - Water loss (perishables) - Immediately after harvesting – control conditions (perishables, etc) Pre-harvest Product of the plant Harvest Handling, primary Produce processing & packaging Product Marketing, distribution Related commodity Terminology  Fruits and Vegetables Exporting Pre-harvesting Harvesting Post-harvest treatment Selection & grading Packaging Cold storage Air Transport Sea/Land Transport Quality conversion by importers Commercialization Logistical Chain Consumer shelf  Self-learning section 01. Pre-harvest factors affecting postharvest quality of Perishables 02. Present Status, Issues and Future Trends in Fruit and Vegetable Handling, Distribution and Marketing in Sri Lanka Pre-harvest factors affecting postharvest quality of Perishables Affect on: Taste Yield Nutrient composition Length of PHT life Magnitude of Decay, Insect damage, and physiological disorders  Cultivar and rootstock genotype: Could be minimized by selecting the most suitable genotype for a given area/Envt.. Breeding and GEng is done to develop new cultivars with resistance to postharvest pest & diseases, improved nutritional quality, taste etc.  Mineral nutrition Nutritional status affects the quality at the harvest and PHT life of Fruit & Vegetables (F&Vs) Deficiencies, excesses or imbalances will course disorders leading to reduced storage life N is the most important nutrient. ie. Leaf nitrogen (%) level for best fruit quality Vegetable crops; excessive leaf N leads to delay maturity and increase some disorders that reduce PHT Quality. Ie. Internal browning in tomato (Grey wall), Hollo stem of Broccoli, low TSS in potato, increased weight loss in sweet potato Excessive soil N, -ve effects: Reduced Vit C level, low sugar, low acid content. -tomato (leafy vegies under shade …. Accumulation of high (unhealthy) nitrate levels) Flavour changers of celery due to reduced volatile production, Beet – increase of glutamine leading to off-flavours Ca deficiency – Blossom end rot of tomato, cracking carrots, tip burn in lettuce Increased levels of K in soil, reduce the colour disorders of crops Higher soil Mg levels increase colour disorders (solution: Add potassium and gypsum together) Foliar Nutrient Sprays Ca is very important, affects on fruit quality In apples and pears: reduce metabolic disorders and decay, maintain firmness For apples, need to raise Ca level upto 800 to 1000 mg/g d.b. Have to use sprays and cannot achieve by soil fertilizer Vacuum infiltration of CaCl2 has also been tried for some fruits; Peaches –287 to 1088 mg/g d.b. increase firmness but no reduction of decay Irrigation Affects on fruit and vegetable quality Increased water stress increase bitterness of cucumber Banana, Water stress before harvest – reduce splitting, increase TSS (sweetness) Banana – irrigation/rains before harvest aggravate fruit splitting, reduce TSS Melon: Over irrigation leads to low TSS and increased rots  Irrigation after long soil moisture stress period: cracks in carrots, potatoes, tomatoes Onions: storage diseases; neck rot, black rot, basal rot due to excessive moisture Strawberry, irrigation during ripening decreases sugar content and firmness (More prone to mechanical damage) “Water stress never increase the yield but increase some fruit qualities”  Canopy Manipulations Fruit let thinning - increase fruit size and sometimes TSS Fruits exposed to sun light: large size, increased TSS and changes of acidity Grapes- increased aroma, TSS, anthocyanins and total soluble phenols BUT reduced acidity and K content SOME CROPS LIKE BERRIY FRUITS ,Fruits to Leaf ratio affects on the quality of fruit Crop Rotations Reduce the PHT losses by reducing decay inoculums in production fields Prevents the accumulation of soil-borne fungi, bacteria, and nematodes Crop sanitation also reduces PHT losses due to reduced decay  Organic Culture Research evidences are available on longer shelf life of organic crops Higher demand due to no chemical residues Increased eating quality Less decay after harvest Vermicompost applied tomato crop, registered significantly higher shelf life when stored at room temperature compared to inorganic culture Organic… Next Session Postharvest Loss Thank you…!!!