تاثير تيمار دمايي بر كاهش اسيديته و بهبود كيفيت ميوه نارنگي ساتسوما و ارتباط آن با فعاليت آنزيم آكونيتاز

EFFECTS OF HEAT TREATMENTS ON REDUCING ACIDITY FOR IMPROVING QUALITY IN ʹSATSUMAʹ MANDARIN FRUIT AND ITS RELATION WITH ACONITASE, VACOULAR AT PASE AND PPASE ACTIVITY

Acidity content of fruits is influenced by preharvest environmental factors, horticultural practices and postharvest conditions. In this study, the effect of different heat treatments (temperature conditioning and hot water dipping) on acidity content and key enzymes activity in organic acid synthesis and accumulation of organic acid ʹSatsumaʹ mandarin fruits was investigated. Acidity content and key enzymes activity signficantly changed during storage periods. Although activity of aconitase in juice sac declined during storage conversely, but isocitric-dehydrogenase (ICDH) activity increased slightly. During storage induced V-PPase and V-ATPase gene transcript level has increased in most heat treated fruits which was probably associated with acid content in the juice. Heat treatments could not influence significant differences in juice acid percentage. In contrast, sugar content and sugar to acid ratio may affected by heat treatments. The amount of V-PPase and V-ATPase gene transcript in fruit pulp considerably affected by various heat treatments.