响应面优化大豆粕合成N-月桂酰基复合氨基酸工艺研究

以大豆粕为原料,采用加压酸解的方法制备了复合氨基酸溶液,再与月桂酰氯反应合成了N-月桂酰基复合氨基酸表面活性剂。研究了复合氨基酸溶液与月桂酰氯体积比、p H、反应温度、丙酮与复合氨基酸溶液体积比、反应时间对产物产率的影响,以单因素试验为基础,利用响应面法优化了工艺条件,并对酰化产物的表面活性性能进行了测定。结果表明,响应面优化大豆粕合成N-月桂酰基复合氨基酸工艺条件为:复合氨基酸溶液与月桂酰氯体积比3.2∶1,p H 10.2,反应温度35.5℃,丙酮与复合氨基酸溶液体积比1.6∶1,反应时间2 h。在最佳工艺条件下,产物产率为91.31%,产物表面活性性能良好。     

响应面优化大豆粕合成N-椰子油酰基复合氨基酸工艺研究

以大豆粕为原料,采用加压酸解的工艺制备了复合氨基酸溶液,再与椰油酰氯反应合成了N-椰子油酰基复合氨基酸表面活性剂。研究了复合氨基酸溶液与椰油酰氯体积比、pH、反应温度、丙酮与复合氨基酸溶液体积比、反应时间对产物产率的影响,以单因素试验为基础,利用响应面法优化了工艺条件,并对酰化产物的表面活性性能进行了测定。结果表明,响应面优化大豆粕合成N-椰子油酰基复合氨基酸工艺条件为:复合氨基酸溶液与椰油酰氯体积比4.2∶1,pH 11.2,反应温度36℃,丙酮与复合氨基酸溶液体积比1.7∶1,反应时间2 h。在最优工艺条件下产物产率为91.07%,产物表面活性性能良好。     

响应面优化大豆粕合成N-硬脂酰基复合氨基酸工艺研究

以大豆粕为原料,采用加压酸解的方法制备了复合氨基酸混合溶液,再与硬脂酰氯反应合成了N-硬脂酰基复合氨基酸表面活性剂。以单因素试验为基础,研究了复合氨基酸液与硬脂酰氯体积比值mL/mL、pH、反应温度、丙酮与复合氨基酸液体积比值、反应时间对产物产率的影响,利用响应面法优化工艺条件,并对酰化产物的表面性能进行测定。结果表明,响应面优化大豆粕合成N-硬脂酰基复合氨基酸工艺条件为:复合氨基酸液与硬脂酰氯体积比值2.7、pH 10、反应温度33℃、丙酮与复合氨基酸液体积比值1.25、反应时间2 h。产率为89.96%,产物表面性能良好。     

由蚕蛹蛋白合成N-月桂酰基复合氨基酸表面活性剂

以蚕蛹蛋白为原料水解得到的复合氨基酸液，与月桂酰氯反应合成N-月桂酰基复合氨基酸表面活性剂。探讨投料比、溶液PH值、反应温度和丙酮用量对合成反应的影响，结果表明优化的合成工艺条件为：月桂酰氯：复合氨基酸液：丙酮=1：2：（V／V），反应温度20℃，溶液pH值10，反应时间4小时。产品具有良好的表面活性。     

水力空化作用强化油酸酰氯酰化大豆蛋白工艺的研究

以大豆粕为研究对象,通过水力空化作用强化油酸酰氯酰化大豆蛋白工艺,设计了水力空化作用强化油酸酰氯酰化大豆蛋白设备,研究了水力空化压力、水力空化时间、水力空化温度、料液比对油酸酰氯酰化大豆蛋白产物产率的影响,以单因素实验为基础,利用响应面优化了水力空化作用强化油酸酰氯酰化大豆蛋白最佳工艺,并对酰化产物表面活性进行了测定与比较。结果表明:水力空化作用强化油酸酰氯酰化大豆蛋白最优工艺条件为水力空化压力0.33 MPa、水力空化时间48 min、水力空化温度65℃、料液比1.8∶1,此条件下的产率为98.38%,酰化产物表面活性性能优越。     

由蚕蛹蛋白合成N-硬脂酰基复合氨基酸表面活性剂

以蚕蛹为原料,采用酶-酸两步水解法制备混合氨基酸液,再与硬脂酰氯反应合成N-硬脂酰基复合氨基酸表面活性剂.采用均匀实验考察物料配比、溶液的pH值、反应温度以及反应溶剂等对合成反应的影响,得到合成工艺的优化工艺条件:硬脂酰氯:复合氨基酸液:丙酮:1:1.6:2(体积比)、pH为11、反应温度为37 ℃、反应时间4 h,在此优化条件下氨基氮的平均转化率为70.56%.产品具有良好的表面性能.     

樟树籽仁油合成癸/月桂酰基谷氨酸钠工艺研究

以樟树籽仁油为原料,通过皂化、酰氯化,碱性条件下与谷氨酸钠反应生成癸/月桂酰基谷氨酸钠盐.研究反应温度、pH、反应时间、丙酮与水体积比以及谷氨酸钠与癸/月桂脂肪酰氯摩尔比对癸/月桂酰基谷氨酸钠合成率的影响.得出最佳合成条件为:反应温度45℃,反应时间3h,pH10～11,丙酮与水体积比2∶1,谷氨酸钠与癸/月桂脂肪酰氯摩尔比2∶1.在此条件下,癸/月桂酰基谷氨酸钠的合成率为89.2％.经质谱及红外光谱分析,确定产物为癸/月桂酰基谷氨酸钠.     

水力空化作用强化硬脂酰氯酰化大豆蛋白工艺的研究

以大豆粕为研究对象,通过水力空化作用强化硬脂酰氯酰化大豆蛋白工艺。利用自行设计的水力空化强化装置,采用单因素实验研究了水力空化压力、水力空化时间、水力空化温度、料液比对硬脂酰氯酰化大豆蛋白产物产率的影响。在此基础上,利用响应面优化了水力空化作用强化硬脂酰氯酰化大豆蛋白工艺条件,并对硬脂酰氯酰化大豆蛋白产物表面活性进行测定。结果表明:水力空化作用强化硬脂酰氯酰化大豆蛋白最优工艺条件为水力空化压力0.37 MPa、水力空化时间60min、水力空化温度58℃、料液比1.7∶1,此条件下的产率为95.27%;硬脂酰氯酰化大豆蛋白产物表面活性性能优越。     

利用水解胶原蛋白制备多肽酰胺表面活性剂北大核心

以从皮革废弃物中提取的胶原蛋白为原料,制备了多肽酰胺表面活性剂,探讨了物料配比、溶液的pH值、反应温度以及溶剂用量对合成反应的影响,并研究了产品的表面活性。结果表明:合成的最佳条件为月桂酰氯∶复合多肽液∶丙酮=1∶2∶2(体积比),pH值10,温度为常温。     

松香酰基复合氨基酸表面活性剂的合成研究

以菜籽粕和松香为原料,经菜籽粕的水解,松香酰氯化和缩合反应等合成了N－松香酰复合氨基酸表面活性剂。实验结果表明,松香与三氯化磷反应制取松香酰氯的收率在85％以上,菜籽粕用60mol/L的盐酸在105℃－110℃下水解18h制得复合氨基酸溶液,氨基酸得率为89％,松香酰氯与复合氨基酸进行缩合反应合成了松香酰基复合氨基酸,通过正交回归试验确立的最佳工艺条件为松香酰氯与氨基酸摩尔配比为1．38：1,反应温度22℃,反应时间4.78h,pH7-8,以丙酮／水（v/v)1:1为混合溶剂,转化率达到85．3％,合成产品具有良好的表面活性。     

Effects of abomasal infusions of fatty acids and 1-carbon donors on apparent fatty acid digestibility and incorporation into milk fat in cows

Our primary objective was to determine the effects of the abomasal infusion of 16-carbon (16C) and 22-carbon (22C) fatty acids (FA) on apparent FA digestibility, plasma FA concentrations, and their incorporation into milk fat in cows. Our secondary objective was to study the effects of 1-carbon donors choline and l-serine on these variables. Five rumen-cannulated Holstein cows (214 ± 4.9 d in milk; 3.2 ± 1.1 parity) were enrolled in a 5 × 5 Latin square experiment with experimental periods lasting 6 d. Abomasal infusates consisted of (1) palmitic acid (PA; 98% 16:0 of total fat), (2) PA + choline chloride (PA+CC; 50 g/d of choline chloride), (3) PA + l-serine (PA+S; 170 g/d of l-serine), (4) behenic acid (BA; 92% 22:0 of total fat), and (5) docosahexaenoic acid algal oil (DHA; 47.5% DHA of total fat). Emulsions were formulated to provide 301 g/d of total FA and were balanced to provide a minimum of 40 and 19 g/d of 16:0 and glycerol, respectively, to match the content found in the infused algal oil. Apparent digestibility of FA was highest in DHA, intermediate in PA, and lowest in BA. Digestibility of 16C FA was lowest in BA and highest in PA. The digestibility of 22C FA was highest in DHA relative to BA (99 vs. 58%), whereas 1-carbon donors had no effect on 22C FA digestibility. Plasma 16C FA concentrations were greatest with PA treatment, and 22C FA concentrations were ~3-fold greater in DHA-treated cows relative to all other treatments. Milk fat 16:0 content was highest in PA relative to BA and DHA (e.g., 37 vs. 27% in PA and DHA), whereas the milk yield of 16:0 was higher in PA relative to DHA (i.e., 454 vs. 235 g/d). Similarly, milk 22:0 content and yield were ~10-fold higher in BA relative to all other treatments, whereas DHA treatment resulted in higher content and yield of 22:6 in milk fat relative to all other treatments (41- and 38-fold higher, respectively). Consequently, the content of FA >16C (i.e., preformed) was higher in milk fat from cows infused with BA and DHA relative to PA. De novo FA content in milk did not differ between PA, PA+CC, and PA+S (~16% of milk fat) but was higher in BA and DHA treatments (19 and 21%, respectively). We conclude that FA carbon chain length and degree of saturation affected FA digestibility and availability for absorption as well as their incorporation into milk fat. The abomasal infusion of choline chloride and l-serine did not modify these variables relative to infusing palmitic acid alone.     

Determination of ethanol,volatile fatty acids,lactic and succinic acids in fermentation liquids by gas chromatography

A rapid and simple quantitative method was developed to determine, by gas chromatography, the concentrations in fermentation liquids of ethanol, the C₂-C₆ volatile fatty acids, and lactic and succinic acids. Aqueous samples were acidified with 250μlml^?1 metaphosphoric acid (5:1 ratio), centrifuged, and injected directly on to a column containing a porous aromatic polymer (Chromosorb 101) maintained at 200°C in a gas chromatograph fitted with a flame ionisation detector. It was unnecessary to purify samples further before injection, although distillation and ion-exchange methods were examined. Derivatisation of lactic and succinic acids before injection was not necessary, but the lowest level of detection of these two relatively non-volatile acids was about four times greater than that for the volatile fatty acids. The method described was suitable for the analysis of rumen fluid, methane digester fluid, silage extracts and other anaerobic fermentation fluids. The relative retention times are given for 23 organic acids and six other fermentation end-products.     

奶粉脂肪酸与乳制品风味关系研究

用气质（GC—MS）联用色谱分析了11个商业奶粉样品的脂肪酸组成以及含量,每个样品均检测到了28种脂肪酸,在表现奶粉风味的4个呈味脂肪酸,也即辛酸、己酸、壬酸和葵酸中只检测到了辛酸和葵酸。辛酸和葵酸含量在进口奶粉中普遍高于国产奶粉。国产奶粉中辛酸和葵酸的含量以2号最好,3号其次。亚油酸含量在国产奶粉中普遍高于进口奶粉。     

气相色谱法同时测定保健食品中的5种 不饱和脂肪酸

目的建立气相色谱法同时测定保健食品中亚油酸、α-亚麻酸、二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十二碳五烯酸(docosapentaenoic acid,DPA)的含量。方法样品先采用氢氧化钾甲醇溶液进行皂化处理,再用三氟化硼甲醇溶液甲酯化,经HP-FFAP色谱柱(30m×0.53 mm,1.0μm)分离测定。结果 EPA甲酯、DHA甲酯、DPA甲酯、亚油酸甲酯、α-亚麻酸甲酯分别在0.03927~1.178、0.04200~1.260、0.03449~1.035、0.08368~1.255、0.08482~4.241 mg/mL的浓度范围内线性关系良好,相关系数r均大于0.999;检出限分别为0.0039、0.0042、0.0034、0.0042、0.0042 mg/mL;加标回收率在91.1%~109.3%之间,相对标准偏差均小于5%。结论该方法操作简单快捷,适用于保健食品中亚油酸、α-亚麻酸、EPA、DPA和DHA的测定。     

磁化处理对脂肪酸精馏过程的影响

在不同磁感应强度的磁场中,研究了磁化处理对脂肪酸精馏过程的影响。研究结果表明,磁场对脂肪酸的精馏过程有一定的影响,脂肪酸经磁化处理后,油酸的含量提高0.41%～0.64%,收率提高0.30%～0.47%;亚油酸的含量提高0.46%～0.69%,收率提高0.37%～0.54%;硬脂酸的含量提高0.44%～0.62%,收率提高0.34%～0.48%。由此可见,磁化处理有利于脂肪酸精馏过程的进行。     

Effects of addition of malic or citric acids on fermentation quality and chemical characteristics of alfalfa silage

We studied the effects on alfalfa preservation and chemical composition of the addition of different levels of malic acid and citric acid at ensiling as well as the utilization efficiency of these 2 organic acids after fermentation. Alfalfa was harvested at early bloom stage. After wilting to a dry matter content of approximately 40%, the alfalfa was chopped into 1- to 2-cm pieces for ensiling. Four levels (0, 0.1, 0.5, and 1% of fresh weight) of malic acid or citric acid were applied to chopped alfalfa at ensiling with 4 replicates for each treatment, and the treated alfalfa forages were ensiled for 60 d in vacuum-sealed polyethylene bags (dimensions: 200 mm × 300 mm) packed with 200 to 230 g of fresh alfalfa per mini silo and an initial density of 0.534 g/cm³. The application of malic or citric acids at ensiling for 60 d led to lower silage pH than was observed in the control silage (0% of malic or citric acids). Application of the 2 organic acids led to higher lactic acid concentration in alfalfa silage than in the control silage except with the application rate of 1% of fresh weight. Silages treated with both organic acids had lower nonprotein nitrogen concentrations than the control silages, and the nonprotein nitrogen concentrations in ensiled forages decreased with the increase in malic or citric acid application rates. The application of the 2 organic acid additives led to lower saturated fatty acid proportions and higher polyunsaturated fatty acid proportions in ensiled alfalfa than in the control silage. The amount of malic and citric acids degraded during ensiling of alfalfa was 1.45 and 0.63 g, respectively. At the application rate of 0.5% of fresh weight, residues of malic acid and citric acid in alfalfa silage were 11.1 and 13.6 g/kg of dry matter. These results indicate that including malic or citric acids at the ensiling of alfalfa effectively improved silage fermentation quality, limited proteolysis, improved fatty acid composition of the ensiled forage, and could provide animals with additional feed additives proven to promote animal performance. However, when the application rate of both organic acids reached 1%, the concentration of lactic acid in silages decreased notably. Additionally, 0.5 and 1% application rates also increased the yeast count in ensiled alfalfa.     

过氧乙酸灭菌效果及酸残留的实验研究

目的 研究过氧乙酸灭菌的效果及酸的残留量对pH值的影响。方法 用微生物学无菌检测法和pH值测定法。结果 满载,少量装载,重复灭菌时达到无菌效果,△pH均在0.3～0.4之间。结论 经过氧乙酸灭菌的塑料瓶能达到无菌要求,酸的残留量对pH值的影响不显著,生产上可用过氧乙酸灭菌法对不耐热的内包材进行灭菌。     

Analysis of pomegranate seed oil for the presence of jacaric acid

BACKGROUND: Pomegranate seed oil is predominantly composed of triglycerides containing unsaturated fatty acids, including high levels of conjugated linolenic acids (CLnAs). The major CLnA component, punicic acid, is known to possess biological activity. Consequently, it is desirable to obtain a detailed characterisation of pomegranate seed oil fatty acid profiles, including molecules potentially co‐eluting with punicic acid, such as jacaric acid. RESULTS: Conjugated fatty acid profiles of a commercial sample of cold pressed pomegranate seed oil were characterised in detail by both gas chromatography of methyl esters and by ¹³C NMR spectroscopy. The methylation procedures were found to be critical for determination of accurate fatty acid profiles. GC analysis was unable to resolve jacaric acid from punicic acid, the major fatty acid present in pomegranate seed oil. To establish the presence or absence of jacaric acid, ¹³C NMR was employed. CONCLUSION: This is the first study to investigate pomegranate seed oil for the presence of jacaric acid. Punicic acid, eleostearic acid, and catalpic acid were confirmed by ¹³C NMR, but jacaric acid was not found. Thus, we have shown that punicic acid levels may be accurately measured by gas chromatography alone in pomegranate seed oil. Copyright © 2009 Society of Chemical Industry     

杂多酸催化合成辛酸蔗糖酯

以蔗糖、辛酸为原料,杂多酸为催化剂合成辛酸蔗糖酯。用L16(45)正交设计优化实验,高效液相色谱法分析反应液组成。考察了催化剂种类和用量、反应温度、原料配比、反应时间等因素对辛酸蔗糖酯产率的影响,发现以二甲基亚砜为溶剂、蔗糖与辛酸摩尔比1∶9、磷钨酸用量为蔗糖质量的2.0%、110℃反应时间6h,蔗糖转化率达60%,产物产要是二酯。动力学研究发现,蔗糖反应级数为一级,反应表观速率常数为0.0059min-1(90℃)、0.0117min-1(110℃),反应表观活化能Ea=39.57kJ/mol。     

Growth of Aeromonas hydrophila K144 as Affected by Organic Acids

The influence of different acids on the aerobic growth kinetics of Aeromonas hydrophila was studied in BHI broth with 0.5 and 2.0% NaCl incubated at 5 and 19°C. Growth curve data were analyzed by the Gompertz equation and a nonlinear regression program; generation and lag times were calculated from the Gompertz parameters. Type of acid, pH, NaCl level and temperature influenced lag and generation times. The organic acids (acetic, lactic, citric and tartaric) inhibited growth at higher pH values than inorganic acids (HCl and H₂SO₄). The high NaCl level interacted with type of acid and pH to restrict growth of the organism at the lower temperature of incubation. Acetic and lactic acids were effective in controlling the growth of A. hydrophila and could readily be combined with low holding temperature to render foods free of the organism.