食品科学 ›› 2021, Vol. 42 ›› Issue (6): 61-67.doi: 10.7506/spkx1002-6630-20200210-078

• 食品化学 • 上一篇    下一篇

麦麸阿拉伯木聚糖的羧甲基化改性及理化性质表征

鲁振杰,李娟,陈正行,李诚,李亚男   

  1. (江南大学食品学院,粮食发酵工艺与技术国家工程实验室,江苏 无锡 214122)
  • 出版日期:2021-03-25 发布日期:2021-03-29
  • 基金资助:
    国家食品科学与工程一流学科建设项目(JUFSTR20180203)

Carboxymethylation and Physicochemical Characterization of Wheat Bran Arabinoxylan

LU Zhenjie, LI Juan, CHEN Zhengxing, LI Cheng, LI Yanan   

  1. (National Engineering Laboratory for Cereal Fermentation Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China)
  • Online:2021-03-25 Published:2021-03-29

摘要: 为探究麦麸阿拉伯木聚糖的羧甲基化改性对其理化性质的影响,以碱提取法从麦麸中分离阿拉伯木聚糖,通过单因素试验探究NaOH质量浓度、物质的量比、反应温度和反应时间对羧甲基化阿拉伯木聚糖取代度的影响,并考察不同取代度羧甲基化阿拉伯木聚糖的结构、单糖组成、分子质量、黏度和热稳定性的性质差异。结果表明,当NaOH质量浓度、物质的量比、反应温度和反应时间分别为100 mg/mL、阿拉伯木聚糖-氯乙酸钠-NaOH=1∶2∶2、65 ℃和4 h时,所得羧甲基化阿拉伯木聚糖的取代度最高为0.66,红外光谱分析证明了羧甲基化反应的成功。相比于未改性的阿拉伯木聚糖,取代度为0.66的羧甲基化阿拉伯木聚糖中木糖和阿拉伯糖的含量之和由88.72%减少至14.72%,分子质量也由改性前的6.07×105 Da减小至4.18×105 Da。此外,随羧甲基化阿拉伯木聚糖取代度的增加,剪切黏度呈现出明显的降低,而其热稳定性有所提高,改性样品的最大热分解速率所对应的温度由285 ℃升高至306 ℃。本研究结果表明,麦麸阿拉伯木聚糖经羧甲基化改性后的理化性质具有显著的变化,本实验可为麦麸阿拉伯木聚糖的羧甲基化改性及其应用提供理论依据。

关键词: 麦麸;阿拉伯木聚糖;羧甲基化;羧甲基化阿拉伯木聚糖;理化性质

Abstract: This study aimed to explore the effect of carboxymethylation modification of wheat bran arabinoxylan (AX), prepared by alkaline extraction, on its physicochemical properties. The effects of NaOH concentration, molar ratio of AX to sodium chloroacetate (SMCA) to NaOH, reaction temperature, and reaction time on the degree of substitution of carboxymethylated AX were investigated through single-factor experiments. The structures, monosaccharide compositions, molecular masses, viscosities and thermal stabilities of carboxymethylated AX with different degrees of substitution were studied. The results showed that when NaOH concentration, AX-SMCA-NaOH ratio, reaction temperature and reaction time were respectively 100 mg/mL, 1:2:2, 65 ℃ and 4 h, the highest degree of substitution of 0.66 was obtained. Infrared spectroscopy analysis proved the success of the carboxymethylation reaction. The total content of xylose and arabinose in carboxymethylated AX with the highest degree of substitution was 14.72%, and the molecular mass was 4.18 × 105 Da, both of which were lower than those (88.72% and 6.07 × 105 Da) of the unmodified arabinoxylan. In addition, when the degree of substitution was increased, the shear viscosity of carboxymethylated AX showed a significant decrease, while the thermal stability was increased obviously, as demonstrated by an increase in the temperature for the maximum thermal decomposition rate from 285 to 306 ℃. The results of this study indicated that the physicochemical properties of carboxymethylated wheat bran AX were quite different from those of the original form. This paper can provide a theoretical basis for studies on the carboxymethylation of wheat bran arabinoxylan and its application.

Key words: wheat bran; arabinoxylan; carboxymethylation; carboxymethylated arabinoxylan; physicochemical properties

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