Evolution in the composition of human skin surface lipids during their accumulation on scalp and hair

Qualitative examination of human surface lipids collected using a surfactant solution shows that there are no significant differences between individuals when the samples are collected after one day, starting from clean hair and scalp. On the contrary, samples collected after 4 days reveal discrepancies within the population, related to the oily hair symptom.
An evolution in the composition of the recovered mixture occurs during the 1–4 days accumulation period, which mainly results in an increased unsaturation of the total (free + glycerides) fatty acids fraction isolated after saponification.
A two-step mechanism is proposed to account for the observed evolution: in a first step, free fatty acids are cleaved from glycerides by the well known enzymatic hydrolysis. Analytical determinations show that this process is structure dependant, the straight chain saturated acids being more readily hydrolyzable than the unsaturated and branched chain species. In a second step, free fatty acids are immobilized on the keratinic fibers, by a process which involves the formation of Ca salts.
This evolution results in a decreased viscosity of the skin surface lipids and in an increase of the low temperature melting fraction of the mixture. Its extent is more or less pronounced, depending upon the individuals. Subjects who exhibit extensive evolution are affected by the oily hair symptom.
Evolution de la composition des lipides superficiels humains durant leur accumulation sur le scalp et les cheveux     

Determination of phenolic acids in plant cell walls by microwave digestion

Microwave digestion (750 W for 90 s) with 4 M NaOH was used to release esterified and etherified hydroxycinnamic acids from cell walls of maize (Zea mays L), wheat (Triticum aestivum L), barley (Hordeum vulgare L) and oilseed rape (Brassica napus L) stems. Subtraction of values for saponifiable phenolic acids obtained after treatment with I M NaOH at room temperature from digest results provided a measure of β-ether linked units. These were exclusively (E + Z)-ferulic acid in the cereal straws. Only trace amounts of ether- and ester-linked hydroxycinnamic acids were released from the dicotyledon, ripe straw. Microwave digestion was shown to be an order of magnitude more effective than dioxane-HCl at liberating β-ether bound phenolic acids and as effective, but substantially quicker, than previously described high-temperature alkaline digestions.     

Plasma LCAT Activity and Lipid Subfraction Composition in Obese Beagles Undergoing Weight Loss

The relationship between lecithin:cholesterol acyltransferase (LCAT) activity and weight loss in dogs was investigated. Four experimental weight-loss diets were fed to 12 obese female beagles for 56 days in a partial crossover design (n = 6). High- (HGI) or low- (LGI) glycemic index starch and diacylglycerol or triacylglycerol oils were combined to compose experimental diets with similar fatty acid profiles. Food intake and body weights were measured daily and weekly, respectively. Fasted blood samples were drawn at day 0, day 28, and day 56 to measure plasma LCAT activity and total (TC), unesterified (UC), and esterified (EC) cholesterol concentrations, and for fatty acid analysis of the phospholipid (PL) and EC fractions. The LGI groups lost more weight than the HGI groups due to starch digestibility differences. An HGI starch effect on TC and UC concentrations was observed but was unrelated to weight loss. LCAT activities increased over time but were not different after controlling for percentage weight loss. However, a positive linear correlation was found between LCAT and UC concentrations in all groups. Plasma PL fatty acid profiles reflected the diets fed, but increases in 16 and 18 carbon saturated and monounsaturated fatty acids in all groups appeared to be an effect of fatty acid mobilization from storage sites. Both plasma PL and EC fatty acid profiles were similar with both acylglycerol types and EC fatty acids reflected linoleic acid specificity with minimal diet or time effects.     

酯化大豆蛋白-壳聚糖复合物乳化性及抑菌性

以酯化大豆蛋白和壳聚糖为原料，按照酯化大豆蛋白与壳聚糖质量比为1∶0.1，将酯化大豆蛋白与壳聚糖溶液混合并常温搅拌3 h，制得酯化大豆蛋白-壳聚糖复合物。探讨了pH 5.0下酯化大豆蛋白-壳聚糖复合物的功能性质。采用红外光谱和荧光光谱研究了酯化大豆蛋白-壳聚糖复合物的结构，探讨了酯化改性协同壳聚糖复合改性对复合物乳化性和抑菌性的影响。结果表明，氢键参与了酯化大豆蛋白-壳聚糖复合物的形成过程；在pH 5.0下，相较于酯化大豆蛋白，酯化大豆分离蛋白-壳聚糖复合物（MSPI-CS）、酯化大豆球蛋白-壳聚糖复合物（M11S-CS）、酯化β-伴大豆球蛋白-壳聚糖复合物（M7S-CS）的乳化活性分别提升至10.8 m2/g、9.0 m2/g、12.0 m2/g，乳化稳定性分别提升至88.9 min、71.4 min、95.4 min；MSPI-CS、M11S-CS、M7S-CS对大肠杆菌、金黄葡萄球菌和沙门氏菌的抑菌圈直径均增加；以MSPI-CS、M11S-CS、M7S-CS为乳化剂制备乳液，乳液的平均粒径降低至255.2 nm、315.6 nm、253.6 nm，Zeta-电位绝对值提升至22.07 mV、20.68 mV、22.33 mV，同时乳液存储稳定性提高。     

淀粉疏水改性及其应用

传统变性淀粉只有单一的亲水性质,淀粉的疏水改性成为该领域的研究热点之一,介绍了国内外淀粉疏水改性的研究现状及存在的问题,认为淀粉疏水改性要重点解决低成本、环境友好制备高取代度的产物.     

经皮给药用酯化淀粉基压敏胶的制备与性能研究

以淀粉为主要原料、脂肪酸为淀粉的酯化改性剂、三氯氧磷为化学交联剂、水和甘油为增塑剂,制备了一系列经皮给药用亲水性酯化淀粉基PSA(压敏胶)。采用红外光谱(FT-IR)法对酯化淀粉的结构进行了表征,考察了脂肪酸中碳链长度、交联剂含量和取代度(DS)等对PSA性能的影响,并研究了该PSA中5-氟尿嘧啶(5-FU)和布洛芬(IBU)的经皮渗透行为。结果表明:当m(淀粉粉末)∶m(水)∶m(甘油)=1.0∶0.5∶0.5、w(三氯氧磷)=1.0%和DS=0.086 8时,辛酯淀粉基PSA具有适宜的力学性能,符合经皮给药系统用PSA的使用要求,而且其对5-FU、IBU的经皮渗透性能具有较好的调控作用。     

E20酯化淀粉在涤棉浆纱中的应用

通过3个不同浆料配方的上浆试验,以绿色浆料E20替代PVA用于涤棉纱的上浆,获得了较好的效果。     

种曲微生物技术与酒曲改造

以种曲微生物研究为基础,从种曲微生物优势功能菌组合研发强化菌曲的微生物技术,应用于生产选育产酯菌研制出酯化曲。结合酯化生香理论研究提升酶工程微生物技术,可提高曲酒质量,保证安全生产。     

红曲酯化酶新技术及在中国白酒上的应用

分离出的烟色红曲霉(Monascus Fulginosus)M-101菌株能产生脂肪酶和酯酶，其耐热性在45℃24h酶活保存100％。用其生产己酸乙酯生物合成酯香液，酯化10d己酸乙酯含量达1080mg/100ml，30d达2370mg/100ml，80d可达7230mg/100ml。该生物酯化液可用于传统工艺白酒增香、丢糟酒串香、固液结合配制酒加香等多种用途。红曲还可用于其他酿造食品及医药等领域。(晓)