浓缩大豆磷脂制取工艺及设备的研究

对水化油脚采用新工艺和新设备制取浓缩大豆磷脂，并对制取浓缩大豆磷脂的影响因素进行分析和优化，得到了制取浓缩大豆磷脂新工艺和最佳工艺参数。     

Study of the refirming effect of a plant complex

Loss of skin elasticity is one of the main problems of ageing. This is a mechanical property influenced by elastin, a protein in the dermis which, together with collagen and glycosaminoglycans, makes up the connective tissue. This tissue is affected by a large number of events (such as cutaneous ageing, pregnancy, slimming processes and cellulitis) which eventually cause it to change. At the same time, the metabolism of the proteins of the connective tissue decreases and there is an ever greater presence of enzymes, principally elastases and collagenases, which are responsible for breaking down the elastin and the collagen. One way to prevent such a loss of elasticity is to use active ingredients that are able to inhibit elastase enzymes. A plant complex was prepared using the following plants: lady's thistle (Silybum marianum GAERTN), alchemilla or yarrow (Alchemilla vulgaris L.), horsetail (Equisetum arvense L.) as well as germinated seeds (Glycine soja Siebold and Zucc., Triticum vulgare Vilars, Medicago sativa L., Raphanus sativus L.). The complex was standardized to give the corresponding active principles, silybin, tannins, silicon and peptides, respectively, and in vitro enzymatic tests were carried out to establish its ability to inhibit elastase. The study of enzymatic inhibition was carried out using two enzymes: (1) porcine pancreatic elastase (PPE), and (2) human leukocyte elastase (HLE). The results showed that the plant complex presents non-competitive inhibition in the order of 41.0% against PPE and 50.0% against HLE. An in vivo test was made alongside the in vitro test using an SEM 474 Cutometer (Courage & Khazaka) to study the elasticity of the skin, and positive effects were obtained when applying a cosmetic formulation containing 5% of the plant complex. Image analysis of duplicates of the cutaneous surface, before and after treatment began with a product containing 5% of plant complex and showed that wrinkles were decreased by 36.7%.     

微波消解原子荧光光谱法测定炼乳中的锡

研究了微波消解一原子荧光光谱法测定炼乳中的痕量锡，在最佳仪器条件下，考察了不同酸介质、KBH4质量浓度、酸介质质量浓度对锡检测结果的影响，并对测定锡时共存离子的干扰和消除进行了探讨，建立了盐酸作为介质，铁氰化钾为还原剂，草酸作为掩蔽剂的检测方法。本方法的线性范围为1.12～200μg／L，相关系数r〉0.999，检出限为1．1214μg／L，相对标准偏差为1.11％～1.89％，回收率为93.2％～102．4％。     

Ruminal degradation of tannin‐treated legume meals

The inefficiency of protein utilisation by ruminants fed protein concentrates (based on legume meals) causes serious economic loss and environmental damage owing to their rapid hydrolysis and deamination in the rumen. Thus efforts aimed at slowing the ruminal fermentation of such feeds are needed, and recent studies have observed potentially positive effects of tannins on ruminant nutrition under certain circumstances. Tannins are a complex group of naturally occurring plant polyphenols characterised by their ability to bind with proteins. This property of tannins is considered responsible for the decreased ruminal digestibility of forages both in vivo and in vitro. Under that perspective, commercial tannic acid was added at three proportions (10, 25 and 50 g kg^?1 on a dry matter basis) to four different legume meals (horse bean, kidney bean, soybean and pea), and the effect on in situ dry matter and crude protein ruminal disappearance was assessed. The results confirmed the dose‐dependent (although not persistent after 48 h) slowing of in situ digestibility, this effect being significant at the highest tannin treatment when compared with untreated samples. Scanning electron microscopy revealed that soybean seed endosperm cell walls were protected from digestion by the ruminal microbiota, while the digestion of starch granules was relatively unaffected by tannic acid. Electrophoresis of the protein fractions confirmed the lower digestibility of tannin‐treated seeds as well as the relative lack of alteration of the electrophoretic profile of individual proteins. Implications for the digestion of concentrates in ruminants are discussed. Copyright © 2004 Society of Chemical Industry     

单宁酸对酪蛋白酸钠的作用方式分析

单宁酸能使食物中的蛋白质变成不易消化的凝固物质,影响人体对蛋白质的吸收利用,为了阐明二者之间的作用方式,实验利用差热-热重分析、傅里叶红外光谱和荧光光谱研究了单宁酸(Tannic acid,T)对酪蛋白酸钠(Sodium Caseinate,SC)结构的影响。红外光谱表明,酪蛋白酸钠和单宁酸相互作用后,其二级结构发生了改变,β-折叠和β-转角含量相应地减少,α-螺旋、无规则卷曲结构增多;荧光光谱说明,T的加入可以使SC的荧光发生静态猝灭,由荧光强度变化速率和单宁酸的浓度的双对数回归曲线得出了T和SC的结合常数KΛ=1.30×103 L/mol,结合位点数n=1.20;热重和差热分析表明,单宁酸-酪蛋白酸钠复合物(T-SC)的玻璃化温度升高了20℃,变性温度升高了86℃。分析实验结果:单宁酸的存在使酪蛋白酸钠分子链之间的作用力增大,链段移动受阻,形成更大的立体网状结构,稳定性增加。     

高梁中单宁含量测定方法的研究

本文所报道的高梁中单宁含量测定方法的国家标准,是在ISO－9648方法基础上起草制定的,结合我国基层实验室的实际情况,针对ISO－9684方法的各种测定条件,做了适当的修改,对修改后的测定条件,单宁标准品,样品用量,样品粉碎粒度,单宁提取时间,提取液的分离方式,显色反应时间等进行了反复的验证,经过对内蒙古自治区和吉林省18个品种高梁样品单宁含量的测定,结果表明,标准偏差为0－0．03,变异系数CV（％）为0－2．6,由北京谷物油脂化学研究所和成都粮食集藏研究所对其中9个品种单宁含量做了验证,结果表明,三个实验室测定值的平均相对偏差（％）为0．5－3．2,三个实验室测定值的变异系数（％）为2．8－5．8。     

Volatile Flavor Compounds of Sweetened Condensed Milk

ABSTRACT: The volatile compounds of sweetened condensed milk (SCM) were investigated to explain their contribution to SCM flavor. Commercially processed SCM was diluted with water and the volatiles were isolated by simultaneous steam distillation-extraction under reduced pressure. Commercial liquid milk was used for comparison. The odor concentrate was analyzed by GC and GC-MS, and then fractionated by silica gel TLC and preparative GC to determine the contributors to SCM flavor. Major volatile compounds were 10 fatty acids, 14 lactones, 10 ketones, 13 hydrocarbons, 8 alcohols, 4 aldehydes, and 8 miscellaneous compounds. δ-Decalactone and δ-dodecalactone were the principal contributors to SCM flavor although the other lactones may contribute as well.     

Fermentation characteristics,aerobic stability and ruminal degradation of ensiled pea/wheat bi‐crop forages treated with two microbial inoculants,formic acid or quebracho tannins

This study evaluated the effects of two commonly used microbial inoculants (Lactobacillus buchneri (LB) and Lactobacillus plantarum (LP)), formic acid (FA) and quebracho tannins (QT) on the fermentation quality, aerobic stability and in situ rumen degradation of pea/wheat bi‐crop forages. Precision‐chopped spring pea (Pisum sativum, var Magnus) and wheat (Triticum aestivum, var Axona) bi‐crops (3:1 pea/wheat ratio) harvested at a combined dry matter (DM) content of 301 g kg^?1 were used for the study. The bi‐crops were conserved without (Control) or with inoculants based on lactic acid bacteria (LB (10⁵ CFU g^?1 fresh weight (FW)) or LP (10⁶ CFU g^?1 FW)), QT (16 g kg^?1 FW) or FA (2.5 g kg^?1 FW) in laboratory silos of 1.5 kg capacity, with each treatment being replicated six times. The pH, chemical composition, aerobic stability and in situ rumen degradation of DM, nitrogen (N) and neutral detergent fibre (NDF) after 112 days of ensilage were measured. The average pH at silo opening was 4.0, suggesting that the silages were well fermented. There were no significant effects of additive treatment on water‐soluble carbohydrate, total N, soluble N, ammonia N and NDF. Lactic acid and acetic acid were the main fermentation products. High concentrations of acetic acid were found in all the treatments, indicating a heterofermentative pathway. Although FA treatment gave the most aerobically stable silage, the Control and QT‐treated silages did not heat up by more than 1 °C until after 6 days of exposure to air. There were no effects of additives on DM degradation characteristics. However, the inoculants increased the rate of N and NDF degradation in the rumen, and both FA and QT reduced the effective and potential degradation of N. © 2001 Society of Chemical Industry