冷冻保护剂葡聚糖-聚赖氨酸对冷冻皇冠梨品质的影响

为了解冷冻保护剂葡聚糖、聚赖氨酸对冷冻皇冠梨品质的影响,以氯化钙、氯化钙-葡聚糖、氯化钙-聚赖氨酸、氯化钙-葡聚糖-聚赖氨酸为冷冻浸渍液对皇冠梨进行冷冻处理。用无纸化温度记录仪测定冻结时间,分析样品冻结过程中温度随时间的变化,并对冻融后样品进行汁液损失、质构、水分分布等指标测定。结果表明:氯化钙、氯化钙-葡聚糖、氯化钙-聚赖氨酸、氯化钙-葡聚糖-聚赖氨酸浸渍冷冻处理样品通过最大冰晶生成带所需时间分别为12.87、10.12、10.20、7.50min,加入冷冻保护剂浸渍冷冻的样品解冻后汁液损失显著降低(P＜0.05)。冷冻保护剂浸渍冷冻处理组抗坏血酸含量、硬度较氯化钙浸渍冷冻对照组均有所提高,样品液泡水(T₂₃)所对应的峰面积S₂₃也有一定程度的提高。研究结果表明,与氯化钙浸渍冷冻相比,加入冷冻保护剂葡聚糖和聚赖氨酸后能有效降低冷冻对梨细胞结构的损害,减少营养物质的流失,有利于维持产品品质。

Effect of Dextran-Polylysine Cryoprotectant on Quality of Frozen Crown Pears

In order to understand the effect of cryopreservation agents dextran and polylysine on the quality of frozen crown pear, calcium chloride, calcium chloride-dextran, calcium chloride-polylysine, and calcium chloride-dextran-polylysine were used as cryopreservation solution to impregnate crown pear. The freezing time was measured by a paperless temperature recorder, and the temperature change with time during the freezing process was analyzed. The indexes such as juice loss, texture and water distribution were measured after freeze-thaw. The results showed that the time required for the calcium chloride, calcium chloride-dextran, calcium chloride-polylysine, and calcium chloride-dextran-polylysine immersion freezing samples to pass through the maximum ice crystal formation zone was 12.87,10.12,10.20 and 7.50min. Moreover, the juice loss of cryoprotectant impregnated samples significantly (P<0.05) decreased. The ascorbic acids contents and hardness of samples in the cryoprotectant impregnation group increased compared with that of the calcium chloride impregnated freezing control group. Meanwhile, the peak area S₂₃ corresponding to the sample vacuole water (T₂₃) also increased to a certain extent. Compared with the traditional calcium chloride immersion freezing, the addition of protective agent dextran and polylysine could effectively reduce the damage of freezing to pear cell structure, reduce the loss of nutrients, and help to maintain the product quality.