Crop Processing Methods

Introduction to Postharvest and Its Principles

• Postharvest Principles are critical in maintaining quality, protecting food safety and reducing losses between harvest and consumption
• Correct postharvest handling is advantageous over boosting production in addressing food needs

PostProduction vs. Postharvest

• Postharvest handling is a general term for managing crops from harvest to consumer
• Postproduction refers to the movement of commodities and processes before meal preparation that includes marketing and distribution technology

Principles of Postharvest Handling

• The key principles include practices to:
  • Keep products cool
  • Avoid moisture loss
  • Slow down undesired chemical changes
  • Avoid physical damage
  • Delay spoilage
  • Reduce microbial contamination
  • Maintain quality (appearance, texture, flavor, nutritive value)
  • Protect food safety
  • Reduce losses between harvest and consumption

Postharvest System

• A postharvest system is a dynamic network of interconnected functions and operations within a sphere of activity
• It encompasses the delivery of crops from harvest to consumption, minimizing losses, maximizing efficiency, and ensuring optimal returns for all involved parties
• It can be considered the same as a "chain" or "pipeline", highlighting the succession of operations but sometimes overlooks their complex interactions
• Technical activities include harvesting, field drying, threshing, cleaning, additional drying, storage, and processing
• Economic activities include transporting, marketing, quality control, nutrition, extension, information and communication, administration, and management

Stages of a Whole Postharvest System

• The stages are in this order:
  • Harvesting
  • Threshing
  • Drying (and transport/distribution)
  • Storing
  • Processing
  • Primary processing, which includes cleaning, classification, dehulling, pounding, grinding, packaging, winnowing, drying, sieving, whitening, and milling
  • Secondary processing involves mixing, cooking, frying, molding, cutting and extrusion
  • Product evaluation includes quality control and standard recipes
  • Packaging involves weighing, labeling and sealing
  • Marketing includes publicity, selling and distribution
  • Use
  • Consumer preferences
  • All of the above result in recipes of traditional dishes and new dishes

Main Elements of Postharvest System

• Harvesting is determined by the degree of maturity
• Pre-harvest drying ensures good preservation but increases the risk of attacks and molds
• Harvesting before maturity can entail loss through molds and decay
• Transport depends on the place and conditions where the harvest is to be stored
• The length of time needed for post-harvest drying depends on weather and atmospheric conditions
• Threshing involves separating grains or shells from their plant portions
• Storage requires adequate facilities, hygiene, and monitoring for effective, long-term preservation
• Excessive hulling or threshing during processing can cause cracks and lesions in grains
• Marketing is the definitive conclusion of the postharvest system

Relationship of Fields of Study Under Postproduction

• Postharvest Handling Technology aims to keep harvested commodities in an acceptable state for palatability
• Primary Processing of Plantation Crops involves handling crops, like coffee and cacao, widely grown for industrial processing, and prepares them for industrial processors
• Seed Technology specializes in seed crops for planting, aiming to maintain seed viability until planting time

Perishable vs Durable Crops

• Perishable crops include:
  • Fruits
  • Vegetables
  • Florist crops
  • Young coconut
  • Medicinal crops used in their fresh form
  • Perishable staple root crops
  • Nursery stocks
• Durable crops include cereal grains, grain legumes like peanuts.

Extent of Postharvest Losses of Fruits and Vegetables

• Assessments are rough approximations due to a lack of comprehensive information
• Estimations are informed judgements based on scientific measurements
• Postharvest losses significantly waste production output in developing countries
• Losses can range from 10-50%, which wastes land, inputs, and labor resources equivalent to millions of dollars in countries that need it the most

Postharvest Losses Definitions

• Postharvest losses are measurable reductions in foodstuffs and can affect either quantity or quality
• Losses arise because fresh agricultural produce is living and undergoes changes during its handling
• Losses should not be confused with damage, which is a visible sing that restricts the use of a product

Principal Causes of Postharvest Losses and Poor Quality

• Common causes:
  • Rough handling
  • Inadequate cooling
  • Temperature maintenance
  • Lack of sorting to remove defective produce before storage
  • Inadequate packaging materials
• Minimizing rough handling, sorting to remove damaged produce and effective temperature management is critical

Postharvest Losses by Commodity

• Root vegetables: Mechanical Injuries, improper curing, sprouting and rotting, water loss, decay, and chilling Injury
• Leafy vegetables: water loss, loss of green color, mechanical injuries and relatively high respiration rates, and decay
• Immature fruit and vegetables: over maturity at harvest, water loss, bruising, chilling injury and decay
• Mature fruits and vegetables: bruising, over-ripeness, water loss, chilling injury, compositional changes and decay

Types of Losses

• Foodstuff are edible products fit for human consumption
• Grains and seeds are cereals, pulses and oilseeds grown in most climates and latitudes for human consumption
• Postharvest is the period between exit of field and before culinary prep
• Food loss is the total modification or decrease of quality food that makes it unfit for consumption
• Quantitative loss is a reduction in physical substance, like weight and volume, and are measurable
• Qualitative loss affects the food value an reproductive ability
• Moisture content the amount of free water in the product
• Damage is a deterioration in product which can result in significant loss
• Direct losses occur when leakage an pests results in disappearances
• Weight loss is reduction in moisture content
• Quality loss is from external features odor and taste
• Food loss is from quality or inedibility of product
• Seed viability loss is when set aside sowing preserve their germinative potential.
• Commercial loss translates various types of loss into economic terms
• Irreducible losses from a loss result from respiration or mechanical rubbing

Importance of Proper Postharvest Handling

• Postharvest handling is a complementary method for solving food requirements or of increasing food available

Proper Post Harvest Handling vs. Increasing Yields

• Proper postharvest handling improves nutrition and reduces garbage and pollution issues
• Increasing yield improved by better production practices, variety and expansion
• Proper postharvest handling helps to increase yield to control population growth

Advantages of Proper Postharvest Handling Over Increased Production

• Improving handling practices are less risky than improving yield by additional inputs
• Proper postharvest handling maintains the freshness of produce.
• Proper handling feeds more people without an additional hectare or process being needed
• Energy used to produce otherwise lost materials can be conserved
• Preventing loss if cheaper
• Achieves more rapid results

Explore primary and post-harvest crop processing techniques for perishable and non-perishable crops. Learn about the methods used to maintain viability, extend usability, and prepare crops for industrial applications. Understand the importance of proper storage and moisture control.