冷害桃果实品质劣变及其控制措施

概述了在贮藏期间,桃果实受到冷害后其色泽、质地和风味等品质劣变机理及控制冷害的措施。桃果实的低温褐变主要是酶促褐变,但对不同的品种来说,决定褐变的主导因子则不尽相同。在产生絮败的果实中,果胶物质发生了代谢异常,不溶性果胶明显增加,果胶质代谢异常与PE和PG的活性变化密切相关。桃果实的糖分主要是蔗糖,当冷害出现时桃果实中蔗糖含量迅速下降,可滴定酸含量在贮藏期间也显著下降。目前已从桃果实中分离到近百种芳香成分,冷害桃果实的重要表现之一是原有桃香气变淡或丧失,甚至产生异味。品种与采收成熟度、采前或采后的化学处理、低温锻炼、热调处理和气调均能够不同程度地减轻桃果实的冷害。

Quality Deterioration of Chilling Injury Peach Fruits and Some Alleviation Methods

The quality deterioration mechanism of chilling injury, including flesh browning, woolliness and flavor loss, in peach fruits during low temperature storage is reviewed, and some methods alleviating chilling injury are discussed. Enzymatic browning was the main reason of browning of peach flesh during low temperature storage, but the trigger factor, PPO or different kinds of phenol,depend on different variety. Woolliness development is associated with abnormal metabolization of pectic substances, as a result of low PG activity and continuous PE activity, and consequently the increasing levels of insoluble pectins. The sucrose, which is the main sugar in peach fruits, and the titratable acid decrease greatly in chill injured fruits during storage. About a hundred of aroma substances are extracted from peach fruits, when chilling injury happened, the fragrance of peach is almost dismissed. Chilling resistant cultivars and proper maturity selection, pre or postharvest chemical treatment, cold adaptation, heat conditioning, intermittent warming and controlled atmosphere storage could alleviate chilling injury of peach fruit.