不同护色处理对板栗仁色泽和脂肪酸组成的影响

Effect of Different Color Protection Technologies on Color and Fatty Acid Compositions of Chestnut Kernels

板栗仁中多酚氧化酶(Polyphenol oxidase,PPO)和过氧化物酶(Peroxidase,POD)是导致其褐变的主要因素,本文采用溶剂浸泡护色方法抑制酶的活性,以控制板栗仁褐变。在对板栗仁中PPO和POD稳定性研究的基础上,确定了浸泡护色的温度、时间和pH值等参数。分别研究了浸泡护色处理对板栗仁的总色差(△E*)和脂肪酸组成的影响。结果表明,在pH值小于4.0时,板栗仁中的PPO和POD活性较低,总色差较小。PPO在30℃处理10 min之后,PPO酶活显著下降,而POD在30℃处理25min后,酶活最低。浸泡护色处理的最佳条件为pH值3.8,温度为25℃,时间为20 min。经过此护色处理后,板栗仁油脂不饱和脂肪酸含量略有下降,但主要的脂肪酸亚油酸含量基本不变,该护色工艺对板栗仁油脂脂肪酸组成和风味没有明显影响,可作为有效的板栗仁护色方法。

Polyphenol oxidase （PPO） and peroxidase （POD） are two main factors that lead to browning in Castanea mollissima. Solvent soaking was used to inhibit enzyme activity and protect the color of chestnut kernel. On the basis of the stability studies of PPO and POD, the parameters of temperature, time and pH were determined. Effects of soaking color protection technology on the total color difference of chestnut kernel （△E ＊） and fatty acid composition were also studied. The results showed that when pH was less than 4.0, the PPO and POD activities in the chestnut kernel were lower, and the total color difference was less. PPO activity was significantly decreased after the soaking treatment for 10 min at 30 ℃, while POD activity reached the lowest after the treatment for 25 min at 30 ℃. The optimum conditions for soak color protection process were pH 3.8, temperature 25 ℃, and time 20 min. After this color-protecting treatment, the unsaturated fatty acid content of chestnut lipid decreased slightly, while the major fatty acid （linoleic acid） content remained the same. The color protection technology had little significant effect on the fatty acid composition and flavor of the chestnut and could be used as an effective method of protecting the color of chestnut