不同低温贮藏对荔枝γ-氨基丁酸富集及贮藏品质的影响

Effect of Different Low-temperature Storage Methods on γ-Aminobutyric Acid Accumulation and Storage Quality of Litchi

摘要:

本研究以“桂味”荔枝为试材，探究了冰温贮藏、低温驯化结合冰温贮藏、冷藏三种贮藏方式对荔枝GABA富集的影响，并比较了贮藏期间荔枝质构、色差、感官品质等指标的变化。结果表明：荔枝低温驯化结合冰温贮藏的GABA含量显著增加，且能维持较高水平，最高达15.65 mmol/kg FW，较未低温处理荔枝提高了2.49倍；GABA含量与GAD活力变化呈正相关、与GABA-T活力变化趋势基本相反，表明荔枝GABA富集主要是由于GAD活力上升、GABA-T活力下降所引起的；低温驯化结合冰温贮藏的荔枝其可溶性蛋白、果肉硬度、果皮色泽、感官品质均显著优于直接冰温贮藏和冷藏的样品；荔枝直接冰温贮藏将会出现严重冷害，使其丧失商品价值。低温驯化结合冰温贮藏有利于荔枝GABA的富集及品质的保持，是一种适合荔枝的贮藏方式。

Abstract:

Litchi chinensis Sonn. cv. Guiwei was analyzed to test the effects of ice-temperature storage, cold acclimation combined with ice-temperature storage, and cold storage on γ-aminobutyric acid (GABA) accumulation in litchi. Changes in the texture, color, and sensory qualities of litchi during the storage period were compared. The results showed that GABA concentration in fruits increased significantly from cold acclimation combined with ice-temperature storage; the high concentration was maintained and the peak concentration (15.65 mmol/kg FW) was 2.49-fold higher than that of the sample without cold-storage treatment. GABA concentration was positively correlated with glutamate decarboxylase (GAD; EC 4.1.1.15) activity, and showed an opposite trend with the variation in GABA transaminase (GABA-T; EC 2.6.1.19) activity. This indicates that GABA accumulation in litchi results mainly from increased GAD activity and decreased GABA-T activity. The total soluble protein, fresh firmness, pericarp color, and sensory quality of litchi fruits subjected to cold acclimation combined with ice-temperature storage were significantly better than those of fruits subjected to ice-temperature storage or cold storage. Litchi fruits may exhibit chilling injury in ice-temperature storage without cold-acclimation, decreasing their commercial value. Cold acclimation combined with ice-temperature storage favors GABA accumulation and quality maintenance, showing to be a suitable method for storing litchi fruits.