香辛料调味品褐变机理的分析研究

研究了香辛料调味品在贮藏期间褐变度(DB)及有关成分的变化,分析确定了引起褐变的原因及引起酶促褐变的主要底物,并探讨了香辛料调味品中多酚氧化酶(PPO)的部分酶学特性。实验结果表明,香辛料调味品在贮藏过程中PPO活性和褐变度的变化呈显著负相关性(r=-0.9535),即褐变主要是由酚类发生的酶促氧化所致,香辛料调味品PPO的最适反应pH为6.8,PPO与不同底物结合力的大小依次为焦性没食子酸>酪氨酸>儿茶酚>苯酚>愈创木酚;化学抑制剂CA(柠檬酸)、Na2SO3、Vc、Zn(Ac)2、EDTA-2Na、L-cys和植酸对PPO活性均有不同的抑制作用,尤以Na2SO3、L-cys、CA的抑制作用明显。

Investigation on mechanism of browning in the spice

The relationship between degree of browning (DB) and related ingredients in spice was analyzed during storage. The factors and main substrates resulting in browning were investigated and the enzymatic characteristics of PPO were measured. The results indicate that the changes of PPO activity and DB in spice during storage are negative correlated with r=-0.9535,which indicates that the browning in spice is mainly due to the oxidation of phenols. The optimum pH of PPO activity of the spice is 6.8. The combining capabilities of PPO with several substrates respectively were in order of pyrogallicacid > pyrogallol >catechol >benophenol >guaiacol. The PPO activity could be inhibited by Na2SO3, EDAT-2Na, Zn(Ac)2, CA, Vc, L-cys and phytic acid at varying degrees, while L-cys, CA and have the most profound effects.