柠檬酸对鲜切莲藕酶促褐变的影响研究

Effects of citric acid treatment on enzymatic browning of fresh-cut lotus root(Nelumbo nucifera Gaerth)

研究柠檬酸处理的鲜切莲藕在4℃条件下贮藏15d期间,色差、整体感官质量（OVQ）、多酚氧化酶（PPO）活性、丙二醛（MDA）和总酚（TP）含量的变化。结果表明：与对照组相比,不同浓度的柠檬酸处理对鲜切莲藕的酶促褐变均有一定的抑制作用,且在本实验条件下,柠檬酸浓度越大,护色效果越好。对潜在机理的研究表明,1.5%的柠檬酸处理可显著降低鲜切莲藕中的PPO活性和MDA含量（p〈0.05）,总酚含量在贮藏前期（0~3d）显著高于对照组（p〈0.05）,柠檬酸对PPO和MDA的影响可能是其抑制鲜切莲藕酶促褐变的部分原因。本研究可为鲜切莲藕的保鲜护色提供一定的理论依据。

The efficacy of citric acid on fresh-cut lotus roots under cold condition was investigated. Fresh-cut lotus roots were stored at 4 ℃ for 15 days. Color values, overall visual quality （OVQ）, polyphenol oxidase （PPO） activity, the contents of malondialdehyde （MDA） and total phenolic （TP） were examined every three days during the storage period. The results showed that the different concentrations citric acid can provide inhibitory effects on enzymatic browning of fresh-cut lotus roots compared with the control group, and under the experimental condition, higher concentration of citric acid has better effect of color protection. Further studies about the potential mechanism showed that 1.5% citric acid treatment can significantly reduce the PPO activity and MDA content （p 〈 0.05） . In addition, the content of total phenol also showed lower level （p 〈 0.05） from 0 to 3 days compared with the control group. The effect of citric acid on PPO and MDA may be the reason that inhibiting enzymatic browning of fresh-cut lotus root. This study provides a theoretical basis for fresh-cut lotus root color protection.