水醇溶液中的物理化学叶绿素-a 种类决定了其在紫外光下褪色的速度。
Physico-chemical chlorophyll-a species in aqueous alcohol solutions determine the rate of its discoloration under UV light.
机构信息
Department of Health and Nutrition Sciences, Nishikyushu University, Kanzaki, Saga 842-8585, Japan.
Department of Applied Biochemistry and Food Science Life Chemistry, Saga University, Honjo-machi, Saga 840-8502, Japan.
出版信息
Food Chem. 2019 Mar 30;277:463-470. doi: 10.1016/j.foodchem.2018.11.005. Epub 2018 Nov 2.
Chlorophyll-a (Chl-a) discolors when it is exposed to light, and such discoloration decreases food quality. To elucidate the discoloration mechanism of Chl-a, we determined discoloration rate in different Chl-a chemical species and assessed the size of Chl-a aggregates in mixed aqueous solutions of methanol and ethanol. Chl-a existed as monomer, J-aggregate, and random aggregate in solutions with different alcohol concentrations. The predominant species depended on the alcohol concentration. Monomeric Chl-a and J-aggregates discolored quickly, whereas random aggregates discolored slowly. Particle sizes of J-aggregates were 319 and 2305 nm in diameter in aqueous solutions of methanol and ethanol, respectively. The sizes of random aggregates were 51 and 79 nm in 10% (v/v) aqueous solutions of methanol and ethanol, respectively. The size of Chl-a aggregates positively correlated with the rate of Chl-a discoloration under UV light. Based on the results obtained, we propose a mechanism of Chl-a discoloration.
叶绿素-a（Chl-a）在光照下会褪色，这种褪色会降低食物的质量。为了阐明 Chl-a 褪色的机制，我们确定了不同 Chl-a 化学物质的褪色速率，并评估了甲醇和乙醇混合水溶液中 Chl-a 聚集体的大小。Chl-a 在不同酒精浓度的溶液中存在单体、J-聚集体和无规聚集体。主要物种取决于酒精浓度。单体 Chl-a 和 J-聚集体褪色很快，而无规聚集体褪色很慢。甲醇和乙醇水溶液中 J-聚集体的粒径分别为 319 和 2305nm。在甲醇和乙醇的 10%（v/v）水溶液中，无规聚集体的粒径分别为 51 和 79nm。Chl-a 聚集体的大小与 UV 光下 Chl-a 褪色的速率呈正相关。根据实验结果，我们提出了 Chl-a 褪色的机制。
Zotero 插件