降温方法对不同成熟度鸭梨冰温贮藏中有机酸含量的影响

为了研究不同处理方式对鸭梨中有机酸含量的影响,现采用急速降温和缓慢降温方法对早、中、晚三种不同成熟度的鸭梨进行处理并于冰温下贮藏,在贮藏期间使用高效液相色谱法(high performance liquid chromatography, HPLC)对鸭梨果肉、果皮中的有机酸含量进行测定。研究结果表明：鸭梨果实中主要的有机酸为苹果酸、莽草酸、柠檬酸、草酸,其中有机酸含量主要表现为苹果酸和莽草酸含量最高,柠檬酸含量次之,草酸含量最少。三种采收成熟度鸭梨中四种有机酸含量在冰温贮藏期间总体呈现逐渐降低的趋势。缓慢降温处理后的早、中期采收的鸭梨中主要有机酸含量较急速降温处理高,且与早、晚期采收的鸭梨相比，中期采收的鸭梨中有机酸含量适中。因此,缓慢降温处理结合中期采收的鸭梨能够更好的保持果实中的有机酸含量,从而提高鸭梨品质。

Effects of cooling method on organic acid content of different maturity of Pyrus bretschneideri Rehd. cv. Yali during ice-temperature storage

Objective To evaluate the effect of cooling treatment on the content of organic acids in Pyrus bretschneideri Rehd. cv. Yali during ice-temperature storage. Methods The rapid cooling and slow cooling methods were used to treat Yali pears with 3 kinds of different maturities of early, middle and late maturity and stored at ice-temperature. During storage, the content of organic acids in Yali pear pulp and peel was determined by high performance liquid chromatography (HPLC). Results The main organic acids in Yali pear fruit were malic acid, shikimic acid, citric acid and oxalic acid. The organic acid content was mainly expressed as the highest content of malic acid, followed by shikimic acid and citric acid, and the least content of oxalic acid. The content of 4 kinds of organic acids in 3 kinds of harvest maturity pears showed a decreasing trend during ice temperature storage. The content of malic acid in Yali pear harvested in the early and middle stages of slow cooling treatment was generally higher than that of rapid cooling treatment. The content of citric acid and shikimic acid in the early, middle and late harvested pears treated by rapid cooling were generally higher than those treated by slow cooling. The oxalic acid content of the 3 kinds of maturity Yali pears in the rapid cooling treatment was higher than that in the slow cooling treatment in the early stage of storage, and the later stage of storage was the opposite. In general, compared with the early and late harvested pears, the organic acid content in the middle harvested pears was moderate. Conclusion The slow cooling treatment combined with mid-harvest pear can better maintain the organic acid content in the fruit, thereby improving the quality of pear.