HYPOBARIC STORAGE AND IRRADIATION IN FRUITS AND VEGETABLES

HORTICULTURE

1. HYPOBARIC STORAGE AND IRRADIATION IN FRUITS AND VEGETABLES PRESERVATION

2. HYPOBARIC STORAGE (LOW PRESSURE STORAGE) Hypobaric Storage refers to the storage of fruits and vegetables under reduced atmospheric pressure. The storage life of many fruits and vegetables can be extended by reduced pressure under refrigeration due to low respiration rate and evacuation of ethylene. This is form of Controlled Atmospheric storage (CAS) This was first proposed by Burg and Burgl in 1966.

3. Fruits were held at about 0.2 to 0.5 atmospheric pressure at 15 to 24°Celsius. There was reduction in level of ethylene in the fruits and the oxygen in the chamber. It was found that Reduced oxygen supply slows down respiration and production of ethylene. Flushing of ethylene removed from the fruits out of the storage. Removal of other volatiles produced from fruits and vegetables.

4. Applications: In apple such as carbon dioxide, acetaldehyde, acetic acid esters and a- fernescene , 6-methyl-5-hepten-2-one (MHO), accounts for the results from hypobaric storage. Atmospheric pressure is reduced to 0.10 from normal pressure. Oxygen concentration is lowered from 21% to 2.1%. Ethylene level is reduced to 0.01ppm which does not stimulate ripening. In banana storage life is doubled at 0.55atm and again doubled at 0.33atm.

5. Comparative storage life (In days) of produce stored in Refrigeration and under Hypobaric conditions COMMODITY COLD STORAGE HYPOBARRIC STORAGE PINE-APPLE 9-12 40 GRAPE 30-40 90-120 STRAWBERRY 5-7 21-28 BANANA 10-14 90-150 APPLE 60-90 300 PEAR 45-60 300 CUCUMBER 10-14 41 BEAN 10-13 30 ONION(green) 2-3 15 TOMATO(mature green) 14-21 60-100 TOMATO(breaker) 10-12 28-42 LETTUCE 14 40-50

6. IRRADIATION IN FRUITS AND VEGETABLES PRESERVATION It is exposure of fruits and vegetables to ionizing radiations from radioactive sources under the controlled conditions to disinfect, to sterilize and preserve the produce. It is also called as cold pasteurization. SI unit of irradiation is Gray (J/Kg) These radiations differ in wavelength, frequency, penetrating power.

7. SOURCES OF IRRADIATION Gamma rays from radioisotopes such as cobalt-60 or cesium-137. X-rays from machine sources operated at or below energy level of 5Mev. Electrons generated from sources operated at or below an energy level of 10Mev.

8. ADVANTAGES It is a physical, non additive process causing minimal changes in fruits. Helps to keep the chemical burden in fruits at low level. It helps to preserve the fruits in natural form. Increase level of quality assurance. Nutrition value of fruits is preserved.

9. APPLICATION OF IRRADIATION AT DIFFERENT DOSE LEVELS Low dose: Sprout inhibition in bulbs and tubers (0.03-0.15kGy) Delay in fruit ripening (0.25-0.75kGy) Insect disinfestation (1-10kGy) Medium dose: Reduction of pathogens (2.5-10kGy) High dose: Extends the shelf life of fruits and vegetables (5-7kGy)

10. APPLICATION BASED ON EFFECT OF TREATMENT Radappertization (25-45kGy): This applies dose of ionizing radiation sufficient to bring about commercial sterility in product. Radicidation (2-8kGy): A dose of ionizing radiation sufficient to reduce number specific non spore forming bacteria. Radurization (0.4-10kGy): A dose of ionizing radiation sufficient to enhance keeping quality at refrigerated temperature by reducing viable specific spoilage micro organisms.

11. Sprout inhibition in tuber crops A very low concentration of 0.15kGy or less inhibits sprouting of products such as potatoes, onion, garlic, yam etc. Irradiation inhibits the division in meristematic tissue there by inhibits the sprouts. Irradiation of potatoes combined with refrigeration at 15°C extends storage period about 6 months.

12. Shelf life extension in fruits Irradiation kills micro organisms that cause spoilage and deterioration of fruits. A dose of 5kGy or less to fresh strawberries , papayas mangoes are irradiated and marketed successfully. A dose of 0.3-1kGy can increase shelf life of mangoes by about 1 week In banana it increase shelf life up to two weeks.

13. Delaying in ripening Some temperate zone fruits like apple, pear and apricot require >1kGy for effective inhibition of ripening. Inhibits ethylene production by fruits when irradiated. Ripening of several fruits like bananas, mango, papaya, guava delayed when treated medium dose of radiation.

14. References: Post Harvest Management of Horticulture Crops:- S. Saraswathy , T.L. Preethi , S. Balasubramanyan , J. Suresh, N. Revathy , S. Natarajan. Text Book of Post Harvest Technology of Fruits and Vegetables:- L.R. Verma and V.K. Joshi Fruits and Vegetables Preservation Principles and Practices:- R.P. Srivastava and Sanjeev K umar

15. PRESENTED TO: Mr. KUSHAL ASSISTANT PROFESSOR DEPARTMENT OF HORTICULTURE COLLEGE OF AGRICULTURE B’GUDI PRESENTED BY: SANKETH ASHOK U ID NO. UG14AGR2078 THIRD YEAR B.Sc.(AGRI)