Post harvest Management of Horticultural Crops (2+1)

MINIMAL PROCESSING

Operations such as peeling, slicing, grating or shredding of fruits and vegetables is called minimally processing. It is also called partial/fresh/light processing or pre prepared products.
Purpose of light processing is to serve the customers with fruits and vegetables that are convenient to prepare and yet maintain fresh like quality while containing only natural ingredient.
Consumers are demanding convenient, ready-to-serve and ready-to-eat fruits and vegetables with a fresh quality and appearance. However, these living products require special attention during the whole handling process, from harvest to consumption, to mantain quality.




Examples

1. Shredding of cabbage/ lettuce
2. Shelling of peas
3. Snapping of beans
4. Grating of carrot
5. Cauliflower and broccoli florets
6. Sticks of carrot and celery
7. Trimmed spinach
8. Peeled and sliced potatoes
9. Diced onion
10. Slices of mango cheeks/ melons/papaya/apple/others
11. Pieces of pomelo segments and other citrus fruits
12. Peeled and cored pineapple
13. Chilled peach
14. Pomegranate arils dressing
15. Drying of onion, mango lather, grapes, sun dried tomato
16. Microwaveable fresh vegetable trays


Minimal processing generally increases the rates of metabolic processes that cause deterioration of fresh products. Hence, modified gas atmosphere with low O2 and high CO2 minimise the oxidative browning on cut surface.
Good hygiene + low temperature handling is required to prevent the potential toxic pathogens like Listeria spp., E-coli, salmonella etc.

Important process variable which determines the degree of tissue wounding are:

• Methods of cutting (knives, lasers)
• Equipment maintenance (knife sharpening/cleaning)
• Angle of cut
Various non thermal methods have been used to maintain the freshness of the minimally processed products such as

• MAP
• Moderate vacuum packaging
• Irradiation
• Use of edible film and coatings (essential oils and waxing)
• Naval and new preservatives (eg. bacteriocins, polycationic polymers, anti microbial enzymes )
• High intensity pulsed electric fields
• Oscillating magnetic fields
• Intense light pulse
• Ultrasonics
• High hydrostatic presser
Minimum processing is generally without thermal treatments, excepting French beans which requires very short blanching. Permissible additives and preservatives with restricted levels is used so that it will not alter the sensory attributes helps in retaining the freshness of the produce to a longer period.

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