酸解反应提高植物油氧化安定性的研究

利用低不饱和脂肪酸酸解反应与植物油中的脂肪酸发生置换反应,增加植物油饱和度,提高其氧化安定性。实验证明,酸解反应可以在一定程度上改变植物油的脂肪酸组成,减少不饱和酸的含量,改善其氧化安定性,并且不同的酸有不同的效果。     

酸解反应提高植物油氧化安全性的研究

利用低不饱和脂肪酸酸解反应与植物油中的脂肪酸发生置换反应，增加植物油物和度，提高其氧化安性。实验证明，酸解反应可以在一定程度上改变植物油的脂肪酸组成，减少不饱和酸的含量，改善其氧化安全性。并且不同的酸有不同的效果。     

石榴籽油脂肪酸组成及应用研究

用气相色谱法分析石榴籽油的脂肪酸组成，检出了６种脂肪酸：石榴酸８６．０１％、亚油酸５．１４％、油酸３．８１％、棕榈酸２．９１％、硬脂酸１．５２％，亚麻酸０．６１％，与桐油的脂肪酸组成极其相似。石榴籽油属干性油，是涂料工业的好原料。对水果也有十分明显的保鲜作用。     

米糠油的研究和开发

米糠油是从米糠中提取的植物油，外观为棕色透明液体，溶于氯仿、二硫化碳，不溶于水，分子量806．9。米糠油和其他植物油一样。主要成分是脂肪酸甘油脂，脂肪酸组成中棕搁酸占12％～20％、油酸40％～50％、亚油酸29％～42％，还含有蛋白质和维生素等成分。     

气相色谱法测定栝楼籽油中脂肪酸组成

栝楼籽油为栝楼籽经压榨或溶剂浸出后所得的油脂,本文通过索式提取法浸提得到绿色栝楼籽油,气相色谱法检测了其脂肪酸组成。栝楼籽含油率为37．25％,脂肪酸组成为棕榈酸9．87％,硬脂酸1．37％,油酸29．66％,亚油酸44．29％,另外还检测到一未知脂肪酸,含量为14．83％,经初步推测,应为栝楼酸。本试验为栝楼籽的开发利用提供了基础数据。     

七个豇豆品种籽粒的脂肪酸组成

用气相色谱测定了７个豇豆品种籽粒中脂肪酸相对含量。其中月桂酸为０．８９％,豆蔻酸为１．０４％,豆蔻烯酸为１．１２％,棕榈酸为２３．５９％,棕榈烯酸为２．８７％,硬脂酸为３．１０％,油酸为１２．８３％,豆油酸为２７．５９％,亚麻酸为２６．９８％,以上脂肪酸的变异系数依次为１３．４８％,１５．３８％,１９．０６％,４．１５％,２０．５６％,１２．５８％,４９．８１％,１４．５７％,１７．３８％。饱和脂     

利用开菲尔发酵剂制备牛乳酸马奶酒的研究

对利用生产酸牛乳酒（Ｋｅｆｉｒ）的发酵剂（ＫｅｆｉｒＣｕｌｔｕｒｅ）制备牛乳酸马奶酒（或称模拟酸马奶酒）进行了研究。利用全牛乳、脱盐乳清及植物油、ＶＣ按一定比例配合制得的模拟马乳其主要成分接近马乳的化学组成。制得的模拟马乳用ｋｅｆｉｒ发酵剂进行发酵，经１２ｈ的发酵，其中乳酸含量为０．７３－０．７８％；乙醇含量为０．０２１％－０．０２８％，随发酵的进行，其中ＮＰＮ含量逐渐增多，产品中的游离氨基酸含量     

采用真空转鼓过滤硫化碱泥增加经济效益

七泉湖化工有限责任公司生产硫化碱,采用煤粉还原芒硝法。该法是将粉碎好的原料煤和原料硝按一定比例混合,定量加入炉内进行煅烧,燃料是煤粉,反应生成物称粗碱或叫黑灰,将粗碱用小车送到浸取设备中,用８０℃以上的卤进行热溶浸取,所得浓卤经沉淀澄清后送入蒸发锅进行蒸浓（含Ｎａ２Ｓ６０％）,然后灌桶或制片,得到桶碱和片碱产品。碱渣和碱泥经三级洗涤后,将碱泥加水稀释,用砂泵打入厂外污水池。打到污水池的碱泥水经分析测定如表１。表１　碱泥水测定结果序号排放碱泥水数量ｍ３／日碱泥水中硫化碱含量ｋｇ／ｍ３１２７４７．３…     

光度滴定法同时测定酱油中游离酸和游离氨基氮的研究

本文设计了简便可行的光度滴定装置，探讨了光度滴定法同时测定酱油中游离酸和游离氨基氮的测定条件。结果表明，此法操作简便、快速，有良好的重现性和精密度。用该法不酱油中的游离酸和游离氨基氮，取得了回收率分别为９９．４％￣１０３％和９７．３％￣１０１％，变动系数分别为２．２％￣２．８％和０．３９％￣１．４％的良好效果。经ｔ经验，用本方法测定酱油中游离酸和游离氨基氮不引起系统误差，并且测定结果与我国国家标准     

酸度对蘑菇罐头内壁硫化变色的影响

对蘑菇罐头内壁硫化变色的主要原因进行了分析,探索汤汁酸度对内壁产生硫化铁色斑的影响。结果表明,酸的浓度在0．07％,能促进罐内壁均匀腐蚀,对降低内壁集中腐蚀,减少硫化铁污染能起到一定的效果。     

Short communication: Eicosatrienoic acid and docosatrienoic acid do not promote vaccenic acid accumulation in mixed ruminal cultures

Previous research found that docosahexaenoic acid (C22:6n-3) was a component of fish oil that promotes trans-C18:1 accumulation in ruminal cultures when incubated with linoleic acid. The objective of this study was to determine if eicosatrienoic acid (C20:3n-3) and docosatrienoic acid (C22:3n-3), n-3 fatty acids in fish oil, promote accumulation of trans-C18:1, vaccenic acid (VA) in particular, using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of C20:3n-3 (ETA), control plus 5 mg of C22:3n-3 (DTA), control plus 15 mg of linoleic acid (LA), control plus 5 mg of C20:3n-3 and 15 mg of linoleic acid (ETALA), and control plus 5 mg of C22:3n-3 and 15 mg of linoleic acid (DTALA). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the concentrations of trans-C18:1 (0.87, 0.88, and 0.99 mg/culture), and VA (0.52, 0.56, and 0.62 mg/culture) were similar for the control, ETA, and DTA cultures, respectively. The concentrations of trans-C18:1 (5.51, 5.41, and 5.36 mg/culture), and VA (4.78, 4.62, and 4.59 mg/culture) were also similar between LA, ETALA, and DTALA cultures, respectively. These data suggest that C20:3n-3 and C22:3n-3 are not the active components in fish oil that promote VA accumulation when incubated with linoleic acid.     

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。     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。     

酸味酿造产品中三酸比例评析

酸味酿造产品中乳酸、醋酸、丁酸共存,但比例不同形成的酸味特征也不同。控制不同的环境条件,创造出不同的微生物区系,形成不同的三酸比例,才能形成不同的产品风格。该文对常见的酸味酿造产品中微生物区系的变化及三酸含量进行了分析。     

花生四烯酸、二十二碳六烯酸和二十碳五烯酸 在炎症中的作用概述

心脑血管疾病、肿瘤、糖尿病、神经系统疾病、自身免疫等疾病严重危害着人类的生命和健康,并消耗着大量医疗资源。事实上,很多疾病发生和发展的背后都伴随着炎症反应,炎症是众多疾病的病理基础,甚至是导致这些疾病的诱因。炎症本身是机体的防御性反应,但过度的炎症反应和长期慢性炎症会损害机体的稳态。炎症的调节和控制由炎症介质介导,花生四烯酸(arachidonic acid,AA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)等长链多不饱和脂肪酸(10ng-chain polyunsaturated fatty acids,LC-PUFAs)的衍生物是一类重要的调控炎症的介质。炎性细胞间的交流和细胞内信号传递与LC-PUFAs有关。AA经环氧酶和脂氧合酶合成的类二十烷酸主要起促炎作用,但有的也有抗炎作用。DHA和EPA在体内起抗炎作用,由它们合成的消退素(resolvins,Rvs)和保护素(protectin,PD)是重要的抗炎活性物质。DHA和EPA还可以干扰炎性细胞内信号传导途径来抑制炎症反应。本文从炎症与疾病的关系、LC-PUFAs的衍生物及其促炎和抗炎机制等方面综述了AA、DHA和EPA在炎症中的作用。     

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。     

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。     

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.