有机酸对桑椹花色苷的辅色作用及其热降解动力学规律  

Co-pigmentation of Mulberry Anthocyanins with Organic Acids:Color Enhancement and Thermal Degradation Kinetics

作　　者：陈湘粤 高群玉[1] 李倩[2] 廖森泰[2] 邹宇晓[2] CHEN Xiangyue;GAO Qunyu;LI Qian;LIAO Sentai;ZOU Yuxiao(School of Food Science and Engineering,South China University of Technology,Guangzhou 510640,China;Key Laboratory of Functional Food,Ministry of Agriculture and Rural Affairs,Sericultural&Agri-Food Research Institute Guangdong Academy of Agricultural Sciences,Guangzhou 510610,China)

机构地区：[1]华南理工大学食品科学与工程学院,广东广州510640 [2]广东省农业科学院蚕业与农产品加工研究所,农业农村部功能食品重点实验室,广东广州510610

出　　处：《现代食品科技》2022年第6期116-125,共10页Modern Food Science and Technology

基　　金：广东省重点领域研发计划项目(2020B020225005);广东省农业科学院“十四五”农业优势产业学科团队建设项目(202119TD)。

摘　　要：为探究不同结构有机酸对桑椹花色苷的辅色作用及其热稳定性的影响,采用超高效液相色谱-质谱法分析花色苷组成,以对羟基苯甲酸、原儿茶酸、没食子酸、绿原酸、苹果酸为辅色剂,考察pH值、温度、有机酸质量浓度对辅色反应的影响,并分别在60、70、80℃水浴中模拟食品中花色苷的热降解过程,探究热降解动力学规律。结果表明,在pH=3.5、20℃、960 mg/L质量浓度条件下,“增色效应”和“红移效应”达到最大,辅色效果依次为苹果酸>绿原酸>没食子酸>原儿茶酸>对羟基苯甲酸,苹果酸比空白组A_(λmax)增加45.04%。反应化学计量比(n)、平衡常数(K)、吉布斯自由能ΔG°显示辅色过程均自发进行,苹果酸的平衡常数(K)最大,吉布斯自由能ΔG°最小,分别为26.85、-8.02 kJ/mol。热降解实验表明添加有机酸能延长花色苷半衰期(T_(1/2)),减小降解常数(k),60℃时,没食子酸可将花色苷溶液半衰期(T_(1/2))从17.50 h延长至26.23 h,降解常数(k)从6.6×10^(2)min^(-1)减小至4.4×10^(2)min^(-1)。因此,有机酸辅色作用有助于提高桑椹花色苷的稳定性。The effects of different organic acids on the pigmentation and thermal stability of anthocyanins from mulberries were investigated.First,UPLC-MS/MS was used to analyze the composition of mulberry anthocyanins.Then,4-hydroxybenzoic acid,protocatechuic acid,gallic acid,chlorogenic acid,and malic acid were used as co-pigments to determine the influence of pH,temperature,and organic acid concentration on the pigmentation of the mulberry anthocyanins.The thermal degradation of anthocyanins in food was simulated in water baths at 60,70 and 80℃ to explore the effects of the organic acids on the thermal degradation kinetics of the mulberry anthocyanins.The most significant color enhancement and red-shifting effects were observed at anorganic acid concentration of 960 mg/L,pH of 3.5,and temperature of 20℃.The co-pigmentation effects of the five organic acids were in the following order:malic acid>chlorogenic acid>gallic acid>protocatechuic acid>4-hydroxybenzoic acid.Compared with that of the blank group,the absorbance atλ_(max) of the group treated with malic acid increased by 45.04%.The stoichiometric ratio(n),equilibrium constant(K),and Gibbs free energy(ΔG°)indicated that the co-pigmentation reactions were all spontaneous.Malic acid,demonstrating the best co-pigmentation effect,had the largest K value(26.85)and the smallestΔG°value(-8.02 kJ/mol).Through degradation experiments,it was found that the addition of organic acids could prolong the half-life(T_(1/2))of the anthocyanins and reduce their degradation constant(k).At 60℃,gallic acid prolonged the T_(1/2) of the anthocyanins from 17.50 h to 26.23 h and reduced the k value from 6.6×10^(2) min^(-1) to 4.4×10^(2) min^(-1).Therefore,co-pigmentation with organic acids can effectively improve the stability of anthocyanins from mulberries.

关 键 词：桑椹花色苷 有机酸 辅色作用 超高效液相色谱-质谱(UPLC-MS/MS) 热力学参数 热降解动力学 

分 类 号：TS264.4[轻工技术与工程—发酵工程]