混合保鲜剂浸泡对新鲜莲藕冷藏保鲜过程中色泽和气味的影响

Effect of Mixed Preservative on Color and Odor of Fresh Lotus Root during Storage at Refrigerated Temperature

以"鄂莲5号"品种的新鲜莲藕为试材,以清水浸泡的莲藕为对照组(CK),以含有柠檬酸0.02%、乙二胺四乙酸二钠0.05%、D-异抗坏血酸钠0.02%、脱氢乙酸钠0.01%、亚硫酸钠0.02%的混合液浸泡的莲藕为实验组(EX),分析在冷藏贮藏条件下混合液处理莲藕外观和气味品质的变化,探索混合液浸泡对采后莲藕外观和气味品质的影响。结果表明混合液浸泡可使莲藕表皮中的总多酚含量减少29.24%,同时还使莲藕皮中PPO活性降低了73.88%。莲藕外观和横切片观察知,莲藕褐变主要发生在莲藕表面,混合液浸泡可显著抑制莲藕表面的褐变。电子鼻分析知,混合液浸泡对莲藕初始气味影响不显著,但贮藏时间对莲藕气味影响显著。传感器R(2)、R(6)、R(7)、R(8)和R(9)代表的氮氧化合物、甲基类化合物、硫化物、醇醛酮类化合物和有机硫化物等物质是影响莲藕气味的主要物质。混合液浸泡后莲藕的最佳保质期为32 d,混合液浸泡不影响对莲藕的原有气味产的同时还可显著抑制莲藕表皮褐变。该研究结果为冷藏条件下确定新鲜莲藕的保质期提供基础理论支持。

ER Lotus No. 5’ lotus root was used as test materials. The color and odor of lotus root were measured after lotus root immersed in mixture solution and stored at 4°C. The mixture solution contained citric acid 0.02%, EDTA-Na2 0.05%, D-ascorbic acid 0.02%, sodium dehydroacetate 0.01%, sulfite 0.02%. The sample treated with mixture solution was marked as EX group. In the control group(CK), the lotus root was immersed in sterile water and the others were the same with that in EX group. The results showed that the content of total polyphenol and activity of polyphenol oxidase(PPO) of lotus root in EX group decreased by 29.24% and 73.88% respectively. The browning of the surface of the lotus root was significantly inhibited in EX group. According to the electronic nose analysis, there was an insignificant effect on the initial odor of lotus root between CK group and EX group. However, the storage time had a significant effect on the odor of lotus root in both CK group and EX group. The main substances that affected the odor of lotus root were nitrogen oxides, methyl compounds, sulfides, aldol aldehydes and organic sulfides which were represented by sensors R(2), R(6), R(7), R(8) and R(9). The mixture solution could significantly inhibit the brown of the lotus root peel and did not affect the original smelling flavor of the lotus root. The best shelf life of lotus root after immersion in mixture solution was 32 days. The results of this work provided basic theoretical support for the shelf life of fresh lotus roots under refrigerated conditions.