羧甲基壳聚糖对啤酒酵母脱苦的特性研究

Debittering Effect of Carboxymethyl Chitosan on Beer-brewing Yeast Slurry

摘要:

为了脱除啤酒酵母泥中主要的苦味，利用羧甲基壳聚糖（CMCS）吸附啤酒酵母泥中的苦味物质，研究表明在35 min内，羧甲基壳聚糖对破壁的酵母泥脱苦速率大于未破壁酵母泥的脱苦速率。通过傅里叶变换红外(FT-IR)光谱仪对吸附前后羧甲基壳聚糖的表征以及对羧甲基壳聚糖吸附啤酒酵母中苦味物质过程中的吸附热力学特性、吸附动力学的分析，研究了羧甲基壳聚糖对啤酒酵母脱苦特性。结果表明：羧甲基壳聚糖脱苦未破壁和破壁酵母泥的化学基团可能相同，羧甲基壳聚糖对啤酒酵母泥脱苦过程中参加反应的主要基团是-COOH，-OH也参与了反应。羧甲基壳聚糖对未破壁和破壁的啤酒酵母泥的吸附热力学特性符合Langmuir等温线性模型，吸附动力学过程遵循拟二级动力学模型，吸附过程以单层化学吸附为主。

Abstract:

To remove the main bitter taste in beer brewing yeast slurry, carboxymethyl chitosan was used to adsorb the key bitter-tasting substances. The results showed that the debittering rate of carboxymethyl chitosan on the yeast slurry with cell wall disruption was higher than that on the intact yeast slurry over 35 min. Carboxymethyl chitosan was characterized by Fourier transform infrared (FT-IR) spectroscopy before and after adsorption, the adsorption thermodynamics and adsorption dynamics during the adsorption of the bitter-tasting substances by carboxymethyl chitosan were analyzed, and the characteristics of the debittered beer brewing yeast slurries were studied. The results indicated that the chemical groups of carboxymethyl chitosan involved in the debittering process of the yeast slurries with and without cell wall disruption were probably the same; the main group participating in the debittering process was the carboxyl group (-COOH), and the hydroxyl group (-OH) might also be involved. The adsorption thermodynamics followed the Langmuir model. The adsorption kinetics were well described by the pseudo-second-order equation, which indicated that the adsorption process was dominated by single-layer chemical adsorption.