新型阳离子苯乙烯丙烯酸酯微乳液的研究

研究了阳离子SAE(苯乙烯丙烯酸酯)微乳液的合成及应用.研究表明,通过调节合成单体的配比,可以赋予SAE微乳液不同的用途.当SAE微乳液用作文化纸表曲施胶剂时,用量为绝干纤维的0.25%～0.40%时即可使纸张油墨吸收性达到47%,表而强度达到3.4 m/s,吸水性(Cobb法)达到38 g/m2;当SAE微乳液用作瓦楞原纸表面施胶剂时,用节为绝干纤维的0.20%时,瓦楞原纸正反面的吸水件即可达到40g/m2和44g/m2;当SAE微乳液用作AKD乳化剂时,得到的该AKD乳液应用于瓦楞原纸表面施胶时,下机复卷完即可达到施胶要求,熟化速度快,且用量仪为绝干纤维的0.15%,施胶成本低.     

复合酶法提取鸭血抗氧化肽工艺的研究

以SN-TCA指数和DPPH自由基清除率为指标,采用复合酶(木瓜蛋白酶:中性蛋白酶为2:1),确定制备鸭血抗氧化肽的最佳复合酶解工艺。并在单因素基础上,采用Design-Expert7.0软件设计回归正交实验,用响应面分析法优化各因素及其交互作用的最佳组合。结果表明:温度为55.21℃,时间为1.70h,底物浓度为10.0%,酶用量为0.45AU/g,在此条件下进行实验得出:SN-TCA指数为49.13%,DPPH.清除率为80.75%。     

FORMATION OF TASTE AND ODOR COMPOUNDS DURING PREPARATION OF DOUCHIBA, A CHINESE TRADITIONAL SOY-FERMENTED APPETIZER

Douchiba (DCB), a Chinese traditional soy‐fermented appetizer, is abundantly produced and widely consumed in Guizhou province of southwest China. In this study, an analysis of free amino acid (FAA) profiles, low‐molecular weight peptide fractions (LMWPFs), hydrophobic bitter peptide fractions (HBPFs) and volatile compounds was conducted to understand the changes in taste and odor compounds of DCB during five consecutive manufacturing stages: steamed soybean (SS), 5‐day incubated Koji (Koji), 6‐month fermented Douchi, semifinished Douchiba (sm‐DCB) and 6‐month ripened finished Douchiba (DCB). The total free amino acids (TFAAs) increased significantly from SS to DCB by about 11 times and amounted to 20.1% of the crude protein. Arg, Glu, Phe, Leu and Lys were the most abundant FAA at the end of ripening, and were 64.6% of TFAA. The most abundant taste active FAA classes were the bitter FAA, representing eight‐ and threefold increases over sweet and MSG‐like FAA, respectively. The final values of all bitter and monosodium glutamate‐like (MSG‐like) FAA at DCB stage were significantly higher than their respective thresholds. The ratio of oligopeptides (500～1000 Da) accounted for 13.8 and 2.5% of LMWPF and HBPF, respectively. However, the taste of DCB was predominated by saltiness, followed by moderate “umami” taste and slight bitterness, likely as a result of the balance and interaction among different taste components. A total of 122 volatile compounds were identified, including alcohols, acids, esters, aldehydes, ketones, phenols, sulfur‐containing compounds, heterocyclic compounds, alkines, benzenes and spice aromatics. The subtle aroma of the finished DCB seemed to depend not only on particular key compounds but also on a “critical balance” or a “weighted concentration ratio” of 60 compounds. These volatile compounds, mainly derived from lipid oxidation, amino acid degradation, carbohydrate fermentation, Maillard reaction and Strecker degradation during the microbial metabolism, enzymatic catalysis and spontaneous reactions.     

超临界CO2萃取八角茴香油的GC-MS分析

八角样品在萃取釜压力为15MPa,温度为25℃;分离釜Ⅰ压力为7MPa,温度为30℃;分离釜Ⅱ压力为5MPa,温度为25℃的条件下用超临界CO2萃取2h,所得茴香油经气相色谱-质谱联用分析,共检出157个峰。对其中83个峰进行了鉴定,其中芳香族化合物为八角茴香油的主要组成物质,相对含量为95．1097％,反式茴香脑的相对含量可达92.9327％;其次为萜类化合物,相对含量为3．1454％;非萜类脂肪族化合物的相对含量较低,仅为0．7449％。     

产共轭亚油酸丙酸菌的筛选及转化条件初探

通过富集培养、梯度密度稀释和液体培养发酵,采用紫外分光光度法测定共轭亚油酸(CLA),从市售奶酪中筛选获得1株转化生成CLA能力相对较高的菌株P9:考察了菌体接种量、亚油酸(LA)的添加量、反应温度、反应体系pH值以及乳化剂种类等因素对菌株P9 CLA生成量的影响.通过对菌株P9的菌落和形态特征、产丙酸特性及生理生化特性分析,初步鉴定该菌株为费氏丙酸杆菌(Propionibacterium frudenreichii).研究结果显示,菌株P9在菌体接种量10%(v/v),LA添加量0.75mg/mL,pH值为6.8,反应温度30℃,Tween-80作为乳化剂的条件下,CLA生成量为63.371μg/mL,亚油酸转化率为8.45%,表现出较好的产共轭亚油酸能力.     

金花茶多糖的降血脂功能研究

运用超声波浸提工艺对金花茶多糖进行提取,并通过除蛋白、透析对粗多糖进行初步分离,以初步分离后的多糖喂食高血脂症的小鼠,探讨其降血脂的功能.结果表明:金花茶多糖的高、中、低3个剂量组均能极其显著地降低高血脂症小鼠血清中的TC、TG和LDL-C水平,提高HDL-C/TC比值.灌胃2周后,金花茶组小鼠血清的TC水平均可达到正常组水平,且效果优于血脂康胶囊.结果表明金花茶多糖具有明显的降血脂功能.     

气相色谱法测定葡萄酒中的反式白藜芦醇

采用乙酸乙酯萃取的方法对葡萄酒进行预处理,然后用硅烷化试剂对萃取物进行衍生化,用气相色谱法对葡萄酒中的白藜芦醇进行测定,建立了定量分析的方法.对方法的检出限、精密度和回收率进行了研究,结果表明,该方法的最低检出限为0.04 mg/L,相对标准偏差为0.97%,回收率为94.7%～100.6%,并对市售的7种葡萄酒样品进行了测定.     

自动控制系统在蒸发工段中的应用

本文从蒸发工段传统的人工操作存在的弊端、蒸发自动控制系统的介绍、自动控制系统的应用与经济效益等方面,论述来宾永鑫小平阳糖业有限公司蒸发自动控制系统应用所取得的成果。     

转基因食品标识问题辨析

20世纪90年代以来,转基因作物发展迅猛,转基因食品已进入普通消费者的视野和生活。对转基因食品进行标识以亮明身份,既满足消费者的知情权,同时也便于售后跟踪和风险评估。这个在普通消费者看来非常简单的问题至今也没能拿出统一、可行的标识方案。笔者对这一问题进行初步的辨析和综述。     

丝胶蛋白多肽的制备方法

丝胶蛋白是茧丝绸工业的副产品,经过降解处理后可制成丝胶蛋白多肽.介绍了酶水解、酸水解和碱水解等降解处理制备丝胶蛋白多肤的方法,并对丝胶蛋白多肽的功能及应用前景作了简要概述.