EFFECT OF GAMMA-IRRADIATION COMBINED WITH HOT-WATER DIP AND TRANSPORTATION FROM THAILAND TO CANADA ON BIOCHEMICAL AND PHYSICAL CHARACTERISTICS OF THAI MANGOES (NAHNG-GLAHNG-WAHN VARIETY)

Two lots of mangoes of the Nahng Glahng Wahn variety from Thailand wer e irradiated at the Thai Irradiation Center (TIC) at 0.49 to 0.77 kGy. Following this, one batch was retained in Thailand (TIC) while the ot her was shipped to the Canadian Irradiation Center (CIC) for investiga tion of the same variables during storage. This way, it was hoped to c ompare the effects of gamma radiation with hot water dip (HWI) or with out (I) before and after transportation, on the respiratory activity, rotting, texture, ph, titratable acidity and on the total soluble soli ds in mangoes. Irradiation stimulated carbon dioxide (CO2) production early in the study but delayed ethylene (C2H4) production which peaked later. The production of CO2 and C2H4 occurred later at CIC than at T IC. The I and particularly HWI treatments also delayed the rotting of the mangoes. The texture of the mangoes declined earlier and more rapi dly during storage in Thailand than in Canada. The irradiated samples developped a softer texture early during storage and the rise in pH wa s less marked than the controls. The control showed lower values of to tal soluble solids during the first 10 days of storage but increased l ater.