摘要
为探究甘油作为绿色溶剂提取米糠多酚的可行性,该文选取提取温度、甘油体积分数、液料比和提取时间4个因素,采用单因素结合响应面试验进行米糠多酚提取工艺优化。同时,分析了甘油提取液的黏度特性,并利用超高效液相色谱串联三重四级杆飞行时间质谱(UPLC-Triple-TOF/MS)方法进行多酚鉴定。结果表明,甘油提取米糠多酚最优条件为提取温度67℃,甘油体积分数19%,液料比33 mL/g,提取时间固定为80 min,获得的最大多酚得率为700.35 mg/(100 g)。甘油对米糠多酚的提取效率和甘油的黏度有显著的负相关性。此外,UPLC-Triple-TOF/MS分析表明,最优条件下甘油提取得到13种米糠多酚,其中酚酸质量分数如下:对羟基苯甲酸48.53μg/g,香草酸69.64μg/g,丁香酸33.63μg/g,4-香豆酸361.18μg/g,阿魏酸392.17μg/g,水杨酸34.67μg/g。研究结果表明,甘油可以作为从米糠中提取多酚的绿色溶剂。
During rice-milling process, rice bran is produced as one kind of byproduct with high contents of polyphenols. Although there is a huge amount of rice bran in China, most of it is used to feed animals. Therefore, it is inevitable to fully explore the additional value of rice bran for the economic benefit of rice processing industry. Rice bran can be used for extraction of polyphenols. Conventional solvents are methanol, acetone and ethanol, which exhibit some disadvantages. To overcome these disadvantages, we need to find a suitable solvent to replace conventional solvents. Glycerol is one kind of colorless, odorless, viscous liquid, which is sweet-tasting and non-toxic. It is widely applied in the food and pharmaceutical industry. Glycerol might be a potential alternative for green extraction of polyphenols from rice bran. Thus, in our research, a green extraction process of polyphenols from rice bran using glycerol was studied. Four individual factors including extraction temperature, volume fraction of glycerol, liquid-to-solid ratio and extraction time were chosen, and single-factor experiments combined with response surface methodology (RSM) were applied for optimization of the extraction process. The relationship between extraction efficiency of glycerol and its viscosity, the physical property, was analyzed and a UPLC-Triple-TOF/MS method was also conducted for identification of polyphenols. Results showed the order of independent factors affecting the yield of polyphenols was as follows: extraction temperature> volume fraction of glycerol>liquid-to-solid ratio. The ANOVA analysis revealed that independent factors (extraction temperature, volume fraction of glycerol and liquid-to-solid ratio), interaction effect (extraction temperature and volume fraction of glycerol) and their quadratic terms significantly influenced the yield of polyphenols (P<0.05). The optimum conditions were extraction temperature at 67 ℃, volume fraction of glycerol at 19 %, liquid-to-solid ratio at 33 mL/g and extraction time fixed at 80 min. Under the optimal conditions, the maximum yield of polyphenols was 700.35 mg/100 g. There is a significantly negative correlation between extraction efficiency of glycerol and its viscosity. During extraction processes, the viscosity of glycerol changed as extraction conditions changed. As the viscosity increased there was a significant decrease in yield of polyphenols, with significant negative correlation coefficient value of -0.878 9 (P<0.01). Under the optimal conditions, there were thirteen phenolic compounds identified in the glycerol extract according to UPLC-Triple-TOF/MS analysis. The quantification of all the six phenolic acids was conducted by UPLC. The contents of phenolic acids were as follows: 4-hydroxybenzoic acid (48.53 μg/g), vanillic acid (69.64 μg/g), syringic acid (33.63 μg/g), 4-coumaric acid (361.18 μg/g), ferulic acid (392.17 μg/g), and salicylic acid (34.67 μg/g), which significantly enhanced the value of rice bran.
作者
黄皓
王珍妮
李莉
任国平
罗自生
Huang Hao;Wang Zhenni;Li Li;Ren Guoping;Luo Zisheng(College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China;Hangzhou Wanxiang Polytechnic, Hangzhou 310023, China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2019年第4期305-312,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
浙江科技重点研发计划项目(2018C02049)
杭州科技重点研发计划项目(20170432B24)
关键词
甘油
黏度
农产品
米糠
多酚
优化
glycerol
viscosity
agricultural products
rice bran
polyphenols
optimization
