Effect of fermented rice culture on the microbiological,biochemical and sensory characteristics of low‐salt douchi,a traditional Chinese fermented soybean condiment

A low‐salt (4% NaCl, w/w) douchi supplemented with different concentration of fermented rice culture (FRC) of 0%, 5%, 10%, 15% and 20% (v/w) was produced, and the effect of FRC on microbiology, biochemistry and sensory quantity was investigated. Results indicated that FRC had a significant effect on low‐salt douchi. Compared with the control (added 0% FRC), in the other treatments, the counts of yeast and lactic acid bacteria increased by about 50%, whereas the moulds decreased by about 30%; the pH reduction was close to 4.7; total acid increased to about 1.300 g per 100 g; reducing sugar maintained a decrease to 21.07 mg per g; amino nitrogen increased to about 0.900 g per 100 g, but not above the control (1.013 g per 100 g). In general terms, total free amino acid contents and three organic acids were higher in low‐salt products than four commercial products. Sensory evaluation of products supplemented with 10% and 15% FRC revealed better overall acceptability compared with other treatments and a commercial product.     

Encapsulation of bixin in sodium caseinate to deliver the colorant in transparent dispersions

Bixin, the major colorant component of annatto, is water insoluble and sensitive to degradation by temperature, pH, and light stresses. In this work, we studied an encapsulation process by spray drying warm 40% v/v aqueous ethanol solution with dissociated sodium caseinate (NaCas) and dissolved bixin. Upon hydration of spray-dried powder, transparent dispersions were observed at a wide pH range away from the isoelectric point (pI) of NaCas. The stability of bixin was much improved and the consistent yellow color was obtained. The volume–length mean particle diameters of capsules were around 250 nm in dispersions, slightly bigger than that of NaCas, based on dynamic light scattering, but the difference was not observed based on atomic force microscopy. Capsules and the mixture of NaCas and bixin showed different fluorescence and FTIR spectra. At pH near the pI of casein, soluble soybean polysaccharides adsorbed strongly onto capsules and stabilized them from aggregation. The simple encapsulation approach studied in the present work showed a promising process to enhance the stability and dispersibility of carotenoids using NaCas as a carrier, especially in transparent dispersions.     

Mathematical modelling of soybean oil solubility in supercritical carbon dioxide

The solubility of soybean oil in supercritical carbon dioxide has been determined in the pressure range of 100–300 bar and in the temperature range of 313–323 K. The obtained values (from 0.0005 to 0.02055 g L^?1) have been correlated using four different empirical equations proposed correspondingly by Chrastil, del Valle and Aquilera, Adachi and Lu and Sparks et al. Since the Sparks et al. equation provided the lowest average absolute relative deviation (AARD) (10.25%) than other models in the examined experimental range, a modified equation of Sparks et al. model was developed for predicting the solubility of soybean oil in supercritical carbon dioxide as a function of temperature and density. An improved equation showed the lowest deviation (2.15%) between experimental data than the other empirical equations considered in this study. The proposed equation was also applied for correlating the solubility of linoleic acid (AARD was 2.40%).     

Ring Opening of Epoxidized Soybean Oil with Compounds Containing Two Different Functional Groups

Epoxidized vegetable oils are desirable chemicals due to their eco‐friendly characteristics and their being a major source of many green products. Ring opening is one of the ways to convert these epoxidized oils to some new intermediates. The use of mono‐functional amines, alcohols, acid anhydrides and thioethers for epoxy ring opening has been reported in the literature. In this study, thioglycolic acid (TGA) bearing thiol and carboxylic acid as two different functional groups and methyl ester of thioglycolic acid (TGAME) were used. Currently, there is no reported literature describing epoxy ring opening using chemicals bearing two different functional groups simultaneously. In this way, two new polyols were synthesized, one with TGA (polyol 1) and one with TGAME (polyol 2). FTIR and ¹H‐ and ¹³C‐NMR spectroscopy confirmed that the ring was opened by the carboxylic acid group of TGA, and the thiol group was not involved in the ring opening whereas the ring was opened by the thiol group in the case of TGAME.     

发酵性丝孢酵母处理精炼大豆油废水的工艺优化及动力学分析

在5 L搅拌式反应器内利用发酵性丝孢酵母处理精炼大豆油废水,并采用正交试验优化处理条件,通过极差分析得到精炼大豆油废水生物处理的较佳条件：温度28 ℃、转速300 r/min、进气量2 L/min和接种量10%。在该条件下运行36 h后精炼大豆油废水的化学需氧量和含油量的去除率分别为97.31%和89.09%,生物量和油脂分别达到9.27 g/L和51.9%。通过Monod、Tessier和Moser模型研究了发酵性丝孢酵母生物量增长和精炼大豆油废水的污染物降解,发现相比于Monod和Moser模型,Tessier模型更适合研究微生物的增长,并建立了发酵性丝孢酵母生物量增长的动力学方程式,所得到的动力学参数可用于评估含油废水生物处理反应器的设计和运行。     

豆腐渣厌氧消化产沼气的试验研究

本试验以新鲜豆腐渣为沼气发酵原料,控制厌氧消化温度35±2℃的条件下,采用一次性投料,进行厌氧消化产沼气试验,结果表明:豆腐渣是良好的沼气发酵原料,通过分析消化系统pH值、挥发性脂肪酸(VFA)、日产气量和气体成分的变化可知,在投料比(渣泥质量比)为1∶5、1∶2、1∶1时消化系统的变化是一个正常的水解酸化过程,其单位产气率分别为0.87 L/g TS、1.43 L/g TS、0.93 L/g TS。其中投料比为1∶5的消化系统产生的甲烷含量最高可达81.03%,平均甲烷含量为49.95%。而投料比为2∶1、5∶1的消化系统均出现了酸抑制现象,系统不能顺利进入产甲烷阶段。     

改性大豆蛋白胶黏剂的酸化效应

以浓硫酸为酸化剂，探讨改性大豆蛋白胶黏剂的酸化处理效应。结果表明：随pH值的降低，改性大豆蛋白胶黏剂的颜色逐渐变浅，黏度先逐渐上升再急速下降，胶合强度则先下降后上升。采用酸化处理可明显改善改性大豆蛋白胶黏剂的颜色和流变性能，且不影响其胶合性能。     

大豆粕加压酸解工艺及其产物表面活性的研究

实验研究了加压酸解下大豆粕新溶解工艺,其较佳反应条件为:硫酸质量分数为20%,反应时间为20 min,温度(压强)为110℃(0.104 5 MPa),液料质量比为10。通过对大豆粕溶解液表面活性的测试可知其表面活性较好。