Study on the browning and structure properties of fresh-cut Chinese water chestnut ( Eleocharis tuberosa)

Abstract In this paper, the microstructure, water properties and browning control of Chinese water chestnut (CWC) after harvest were studied. Results showed that the tuber cell contained a large number of starch granules (5-10 μm for each one). The water-holding capacity of tuber cell was weak and T2 relaxation time was 28.5-75.6 ms. Sucrose was the main sugar component in Chinese water chestnut, which account for 84.8% of total sugar. In addition, potassium sorbate, green tea polyphenol and chitosan decreased the browning of fresh-cut CWC compared with the other anti-browning agents such as acetic acid, citric acid, oxalic acid, vitamin C and thyme oil. Moreover, chitosan coating combined with potassium sorbate and green tea polyphenol delayed weight loss and decay of fresh-cut tubers, also maintained a higher soluble solids and ascorbic acid content. The study provided an alternative method for controlling CWC browning, which would be helpful for the application of anti-browning agents in CWC processing.

摘要 本研究针对采收后中国荸荠（Chinese water chestnut, CWC）的微观结构、水分特性及褐变控制展开探究。研究结果显示，其块茎细胞内含有大量淀粉颗粒，单颗粒粒径为5~10 μm。块茎细胞的持水能力较弱，T2弛豫时间为28.5~75.6 ms。蔗糖为中国荸荠的主要糖分组分，占总糖含量的84.8%。此外，相较于乙酸、柠檬酸、草酸、维生素C及百里香油等其他褐变抑制剂，山梨酸钾、茶多酚与壳聚糖均可减轻鲜切中国荸荠的褐变程度。进一步研究发现，壳聚糖涂膜复配山梨酸钾与茶多酚，可延缓鲜切块茎的重量损失与腐烂现象，同时维持较高的可溶性固形物与抗坏血酸含量。本研究为中国荸荠的褐变控制提供了一种可行方案，可为褐变抑制剂在荸荠加工中的应用提供参考。