HARVESTING

• The field of Postharvest starts at harvest
• Harvest is the deliberate picking of commodity – the transition point in  

   the postharvest system.

TYPES OF MATURITY

Harvest/ Commercial Maturity – the stage of development when the plant parts possess the necessary characteristics preferred by consumers.

Used as a basis for deciding when the harvest for commercial purposes but it varies depending on the intended use of the commodity, the preference of the consumer; the variety and whether it is going to be stored or not.

Example: Cucumber – pickle and table use

Mango – pickle and dessert

Roses – unopened or half-open or open

Green papaya – vegetable

Physiological maturity – end of the development stage of a fruit or fruit vegetable when it has developed the ability to ripen normally after harvest. This is any stage of maturity before the onset of senescence.

The stage at which the external and internal characteristics of the fruit allow normal ripening of the harvest.

Example: Papaya fruit showing peel yellowing.

Characteristics of Commodities Harvested at the Proper Stage of Maturity

Longer storage life – many food reserves, slower senescence.

Greater resistance to physiological disorders

Greater resistance to mechanical stress and water loss.

Ripe fruits possess all desirable characteristics.

MATURITY INDICES

Maturity indices are signs or indications of the readiness of the plant for harvest.

Attributes used as guides to determine harvest maturity.

TYPES OF INDICES

SUBJECTIVE TYPE – method which depend on the perception of individual (usually sensory). This could be visual or physical means. Not enough to set definite standard.

OBJECTIVE TYPE – measurable indices

• Physical methods – specific gravity
• Chemical methods – sugars, starch content
• Physiological method – respiration rate, ethylene production
• Phenological methods

HARVESTING METHODS in the Philippines

MANUAL Harvesting

Pulling – (avocado, beans, peas, tomatoes)

Twisting – (citrus, melons)

Bending – (pineapple)

Cutting – (banana, durian, grapes, cauliflower, cabbage)

Cutting/Digging – potato

Considerations in Harvesting

Handling harvested product with care

• Avoid dropping and other causes of injury
• Use pads or liners in baskets or containers
• Avoid direct exposure to the sun
• Use of appropriate harvesting tools and aids  

Discarding diseased, injured or ripened fruits.

• Eggplant: Harvest fruit at immature but of full size (high yield) or size desired by markets before seeds begin to enlarge and harden. Firmness and glossiness are also maturity indicators and can be combined with the number of days elapsed from flowering.

• Cauliflower: Harvest at the tight curd stage and when full size. Overmaturity is marked by elongation of individual curd.

• Cabbage: Harvest heads when firm. Firmness is determined by hand pressure.
• Chili: Harvest fruit when ripe, at least 80% reddening; can also be harvested green for specific purpose but green fruit will not ripen normally as chili is non-climacteric.
• Bitter gourd, cucumber, and yardlong bean: Harvest at desired size but young/immature and tender. Overmaturity is indicated by yellowing in bitter gourd and prominent seed bulging in beans.

Time of harvest

• Harvesting at cooler times of the day minimizes product heat load and  increases work efficiency of pickers.
• In harvesting when the sun is up, the harvested produce should be moved to a shaded area to reduce heat load and water loss and be allowed to dissipate heat before packing.

• Harvesting in the later part of the day is advantageous in certain cases. The produce is less turgid and content in leafy vegetables is also high as a result of photosynthesis during the day which could slow down leaf yellowing after harvest.
• Harvesting during or just after rain is not recommended as wet condition favors microbial growth and enhance tissue breakdown. If harvesting cannot be avoided during rainy days, the produce must be washed and dried properly before packaging.

Harvesting method

• Carefully harvest produce to minimize physical injury and preserve quality.
• Use harvesting aids as they can reduce labor cost, improve harvest efficiency, maintain produce quality, and speed the harvest and field handling. Protective clothing should also be worn for pickers’ protection and fingernails of pickers should be trimmed before harvesting to avoid nail-wounds on the produce.

• Tomato, eggplant, cucumber and other fruit-vegetables: cut the calyx stem free from the plant. Avoid pulling fruit to prevent removal of stem end and damage of plant and fruit for subsequent harvest.

• Cauliflower: Harvesting should be done with great care to prevent damage to the highly sensitive turgid curds. Cauliflower should never be handled at the curd portion of the head.

• Fields may be harvested several times for maximum yield and desired quality.
• Use harvesting containers with smooth surfaces.

Field handling

• Proper implements and care in handling the produce from field to packhouse reduce damage and preserve quality.
• Harvested produce is usually placed in collection containers, preferably plastic crate as it can protect produce from damage better than bamboo basket. Fruit harvested at different stages of ripeness can be sorted during the harvesting and field handling operations by either placing them in separate containers.
• In the farm, harvested produce is often exposed to the sun and in direct contact with the soil which is a rich source of pathogenic and spoilage microorganisms. To avoid these, use appropriate ground cover, field sorting table and makeshift shed.

Figure 4 Some field handling operations for vegetables prior to hauling to the packhouse or transport to mark