Yu Cheng-An, Yang Chun-Yao
Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City 24205, Taiwan, ROC.
Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City 24205, Taiwan, ROC.
J Biosci Bioeng. 2019 Jun;127(6):767-773. doi: 10.1016/j.jbiosc.2018.12.007. Epub 2019 Jan 9.
The effective processing method to produce fermentable sugars and modify the microstructure of black soybean okara using bio-ionic liquid (bio-IL) pretreatment and ultrasound-promoted enzymatic hydrolysis was investigated. The morphology and structural characteristics of okara before and after bio-IL pretreatment and enzymatic hydrolysis under different ultrasonic frequencies were analyzed by field emission scanning electron microscope (FE-SEM), X-ray energy dispersive spectrometer (EDS), and Fourier transform infrared spectroscopy (FTIR). Without pretreatment, the production of total reducing sugar (TRS) under ultrasound (40 kHz/300 W) was 3.4 times of that without ultrasound. Using the bio-IL choline acetate ([Ch][OAc]) in water for the pretreatment of black soybean okara, the TRS production of enzymatic hydrolysis was further increased to 5.2 times of that without ultrasound in 4 h of reaction. The analysis by FTIR and EDS showed that the highly structured matrix of okara was unfolded and broken by the action of combining ultrasound and choline acetate pretreatment, due to which the surface structures with large pores were presented to facilitate the reduction of unfavorable hindrance for enzymatic hydrolysis. The simplified kinetic model was proposed to describe the transport and reaction phenomena of enzymes in a solid-liquid system by using two kinetic parameters to show the impeded behavior of enzyme within the matrix of okara. The combination of bio-IL pretreatment and ultrasound-promoted enzymatic hydrolysis was able to make the efficient structural changes of black soybean okara to enhance the digestion of enzymes, and the okara could be valorized for use in foods.
研究了采用生物离子液体（bio-IL）预处理和超声促进酶解生产可发酵糖并改变黑豆豆渣微观结构的有效处理方法。通过场发射扫描电子显微镜（FE-SEM）、X射线能量色散谱仪（EDS）和傅里叶变换红外光谱仪（FTIR）分析了不同超声频率下bio-IL预处理和酶解前后豆渣的形态和结构特征。未经预处理时，超声（40 kHz/300 W）作用下总还原糖（TRS）的产量是无超声时的3.4倍。使用水中的生物离子液体醋酸胆碱（[Ch][OAc]）对黑豆豆渣进行预处理，在4小时反应中，酶解的TRS产量进一步提高到无超声时的5.2倍。FTIR和EDS分析表明，超声与醋酸胆碱预处理相结合的作用使豆渣高度结构化的基质展开并破碎，从而呈现出具有大孔的表面结构，有利于减少酶解的不利阻碍。提出了简化动力学模型，通过两个动力学参数来描述酶在固液体系中的传输和反应现象，以显示酶在豆渣基质中的受阻行为。bio-IL预处理和超声促进酶解相结合能够使黑豆豆渣发生有效的结构变化，以增强酶的消化作用，豆渣可用于食品加工。
