Date The Physiological And Biochemical Changes In The Hypobaric Storage Conditions And The Storage Effect

Study on the Physiological -. Biochemical Changes and Storage Effects of Jujube Fruits Under Hypobaric(Low Pressure) Condition ABSTRACT In this thesis, studies on the physiological and biochemical changes of LiZao and DongZao under the condition of low pressure were carried out. Correlated relations among different physiological and biochemical indexes were discussed. The suitabler stoage pressures tested for jujube fruits were sifted. Results of the study can be expressed as follows: LiZao and DongZao showed characteristics of non-climateric fruits. The flesh firmness.. fresh rate and the content of titratable acid decreased gradually, which were negatively related to the time of storage signifantlly. Weight loss.. MDA content-. PPO activity-, browning rate increased gradually, which were positively related to the time of storage signifantlly. Duing storage, CAT activity and relative conductivity of pulp showed undulating changes, relative conductivity was positively related to MDA content. Correlated relations between MDA-. relative conductivity and firmness as well as fresh rate were negative. Vc content rised at the early stage of storage and declined later, which were negatively related to the ascorbic acid oxidase activity significantly. During storage, TSS content of DongZao rised like a line while LiZao showed single peak curve change. PPO activity was positively related to browning rate significantly. I-Iypobaric storage slowed down respiration, inhibited ascorbic acid oxidases and PPO activity, reduced the relative conductivity and the accumulation of MDA. The decrease of firmness and fresh rate were significantly inhibited at 20.3kPa (at 1% level). Loss rate of Vc and browning rate were markedly slowed down at 20.3kPa(at 1% level) . Weight loss of jujube fruits were below 2.5% under hypobaric condition. Jujube fruits turned red slowier at 20.3kPa-. 50.7kPa and 8l.lkPa.