AE 3201 Postharvest Technology Quiz

AE 3201 Postharvest Technology

• Postharvest Technology is an interdisciplinary science that focuses on techniques for safeguarding, preserving, processing, packaging, distributing, marketing, and utilizing agricultural produce after harvesting.
• It covers agricultural (plant/animal) produce classified into perishables, semi-perishables, and durables.

Main References & Textbooks

• Postharvest Technology of horticultural crops (A. A. Kader, 2002)
• Tropical products Transport handbook (B. M. McGregor, USDA, 1987)
• Commercial storage of fruits, vegetables, and florist and nursery stocks (R. E. Hardenburg, USDA, 1990)
• Agricultural Process Engineering (S. M. Henderson & R. L. Perry, 1966)
• Produce Handling Packaging and Distribution (K. Peleg, 1985)

Durables

• Durables can be stored for long periods.
• They have low moisture content.
• Respiration rate is low.
• Examples include cereals, pulses, oilseeds, sugar, spices, and plantation products (cashews, copra, tea, coffee, cocoa).

Perishables

• Perishables have a very short shelf life.
• High moisture content.
• High respiration rate.
• Examples include some fruits and vegetables, milk and milk products, meat, fish, and eggs.

Semi-perishables

• Semi-perishables have properties between perishables and durables.
• Examples include potatoes, onions, sweet potatoes, yams, and cassava.

Considerations for Postharvest Technology

• Storage conditions (environmental conditions, relative humidity (RH), temperature)
• Water gain (cereals)
• Water loss (perishables)
• Control conditions immediately after harvesting (perishables).

Pre-harvest and Post-harvest

• Pre-harvest activities include cultivar and rootstock genotype selection, mineral nutrition, irrigation, and canopy manipulations.
• Post-harvest activities include handling, primary processing, packaging, marketing, and distribution.

Fruits and Vegetables Exporting

• The logistical chain includes pre-harvest activities, post-harvest treatment, selection, grading, packaging, cold storage, and air/sea/land transport.
• Quality conversion by importers and commercialization lead to the reaching of the consumer shelf.

Self-Learning Section

• Pre-harvest factors affecting postharvest quality of perishables.
• Status, issues, and future trends in fruit and vegetable handling, distribution, and marketing in Sri Lanka.

Pre-harvest factors affecting Postharvest Quality of Perishables

• Factors affecting taste, yield, nutritional composition, length of postharvest life (PHT life), magnitude of decay, insect damage, and physiological disorders.
• Cultivar and rootstock genotype selection.
• Mineral nutrition.
• Irrigation.
• Canopy manipulations.

Mineral Nutrition

• Nutritional status affects fruit and vegetable quality during harvest and postharvest life.
• Nutrient deficiencies, excesses, or imbalances can lead to storage life reduction and disorders.
• Nitrogen is crucial and excessive nitrogen in some vegetables can delay maturation & lead to quality problems (e.g., internal browning in tomatoes).

Excessive Soil Nitrogen

• Excessive nitrogen can decrease vitamin C, sugar, and acidity content.
• It can also alter flavor and cause off-flavors.
• Calcium deficiency can lead to problems like blossom-end rot, cracking, or tip burn.
• Potassium and gypsum can help reduce color disorders caused by high soil magnesium.

Foliar Nutrient Sprays

• Calcium is essential for maintaining fruit quality, firmness, and preventing metabolic disorders and decay.
• Sprays are used to raise calcium levels to prevent problems in apples and pears, often exceeding what can be achieved via soil fertilization.
• Vacuum infiltration with calcium chloride may also be used in some cases.

Irrigation

• Irrigation affects fruit and vegetable quality.
• Water stress can lead to increased bitterness in cucumbers, reduced splitting and increased TSS in bananas, and increased fruit splitting and lower TSS in bananas with irrigation or rain before harvest.
• Melon over-irrigation can lead to lower TSS and increased rots.
• Irrigation after long soil moisture stress periods cause problems like cracking in carrots, potatoes, and tomatoes.
• Excessive moisture can cause storage disease in onions such as neck rot, black rot, and basal rot.
• Irrigation during ripening of strawberries affects sugar content and firmness and makes the berries more prone to mechanical damage.

Canopy Manipulations

• Fruit thinning increases fruit size and sometimes TSS.
• Sun-exposed fruits tend to be larger with increased TSS and changes in acidity.
• Grapes have increased aroma, TSS, anthocyanins, and total soluble phenols but reduced acidity and potassium.
• Fruit-to-leaf ratios may affect crop quality.

Crop Rotations

• Reduced postharvest losses by minimizing decay inoculums in fields.
• Prevention of soil-borne fungi, bacteria, and nematodes.
• Crop sanitation reduces losses due to reduced decay.

Organic Culture

• Research indicates longer shelf life in organic crops due to the absence of chemical residues.
• Organic products often have enhanced eating quality and reduce postharvest decay.
• Vermicompost can enhance tomato shelf life at room temperature, extending storage life compared to inorganic methods.

Organic Farming Study

• Studies on Organic Farming in Carnations showed higher yield and shelf-life for organic compared to conventional farming. (Specific data is included)

Next Session

• Postharvest Losses

Test your knowledge on postharvest technology, an essential interdisciplinary science concerned with the preservation and processing of agricultural produce. This quiz covers key concepts related to the classification, handling, and storage of perishables, semi-perishables, and durables. Prepare to delve into the methods that ensure quality and safety in agricultural marketing.