为开发安全可靠的荔枝保鲜剂以有效延长其货架期,以"大红袍"荔枝果实为试材,选用d-柠檬烯、柠檬酸等植物源物质与壳聚糖结合采用包封技术制成保鲜剂处理果实,以喷洒清水为对照,放置于(25±1)℃,相对湿度60％～80％条件下贮藏,调查不同时间果实腐烂率和褐变指数,采用电子鼻测定果实气味变化,并测定果肉pH值及可滴定酸含量.结果表明,壳聚糖+维生素C+柠檬酸、壳聚糖+维生素C+柠檬酸+d-柠檬烯两种保鲜剂处理较大程度地减少荔枝果实褐变与霉变所产生的挥发物质.PCA分析显示,两种保鲜剂处理的果实挥发性气体的分布区域重叠或接近,与对照(清水)处理的果实挥发性气体的分布区域明显不同.对照(清水)和保鲜剂处理荔枝果肉pH值和可滴定酸含量随贮藏时间延长而分别增加和降低,而两种保鲜剂处理的果肉pH值和可滴定酸含量相对稳定.两种保鲜剂处理均可有效抑制荔枝果皮褐变,褐变比对照(清水)晚5～7 d,降低腐烂率,从而可延长荔枝保质期5～7 d.
Research on the preparation and application of litchi fruits preservation agents by encapsulating citric acid and d-limonene with chitosan matrix
To develop a safe and reliable litchi preservative to effectively extend its shelf life,'Da Hong Pao'litchi fruits were used as the test material.Plant-derived substances such as d-limonene and citric acid were combined with chitosan using encapsulation technology to create a preservative for fruit treatment,with spray of water as the control.The treated fruits were stored under conditions of(25士 1)℃ and relative humidity of 60％to 80％.The decay rate and browning index of the stored fruits were investigated at different times,and the changes in fruit odor was measured by electronic nose,and the pH value and titratable acid content of the fruit flesh were also determined.The results showed that these two preservatives of chitosan+vitamin C+citric acid,and chitosan+vitamin C+citric acid+d-limonene significantly reduced the volatile substances produced by the browning and mildewing of litchi fruits.PCA analysis revealed that the distribution areas of volatile gases on the fruits treated with the two preservatives overlapped or were similar,which was significantly different from that of control(water)treatment.The pH value and titratable acid content of the litchi fruit flesh treated with water(control)and preservatives increased and decreased,respectively with the extension of storage time,while both preservative treatments showed relative stability.Both preservatives effectively inhib-ited the browning of fruit peel,reduced the decay rate,and delayed the browning of the treated fruits by 5 to 7 days compared to the control(water),thus extending the shelf life of litchi fruits by 5 to 7 days.
万方数据
维普
