植物多酚对脂肪酸合酶活性抑制作用的研究

利用分光光度法观察了不同植物多酚提取物对脂肪酸合酶活性的抑制作用,结果表明,在一定的浓度范围内,多酚提取物均对脂肪酸合酶的活性存在抑制作用,其中茶多酚的抑制效果最佳。     

抽油烟机回收油的脂肪酸组成变化特征研究

食用油在烹饪过程中挥发,会在抽油烟机系统中凝结。分别以花生油、葵花籽油、茶籽油、玉米油和调和油5种不同植物油为食用油进行烹饪试验,收集经抽油烟机系统凝结的油脂。通过测定抽油烟机回收油和相应未烹饪油的脂肪酸,来分析回收油脂肪酸组成变化特征。结果表明,回收油的脂肪酸种类和含量显著性差别于未烹饪油(P0.05)。回收油增加了C14∶0、C16∶1n7c短碳链脂肪酸,其饱和脂肪酸的含量增加了,不饱和脂肪酸含量减少了,其脂肪酸不饱和度明显降低,仅是未烹饪油的50%~61%。回收油中短碳链脂肪酸有增加的趋势,长碳链脂肪酸含量有减少的趋势,而且新增了食用油本底很少或没有的C18∶3n3c和EPA脂肪酸。回收油的品质也开始变化,有些回收油的脂肪酸已严重偏离了正常植物油的特征值。因此,抽油烟机回收油已不适合再食用,烹饪过程中应降低烹饪温度以减少食用油的变质。     

温度对海洋微藻生长及脂肪酸组成的影响

研究了不同温度下,三角褐指藻和等鞭金藻生长及脂肪酸组成.结果表明,三角褐指藻的最适生长温度为20℃,而等鞭金藻的最适生长温度为25℃.无论是三角褐指藻的EPA还是等鞭金藻的DHA,均随着培养温度的升高而下降.低温有利于三角褐指藻积累EPA和PUFAs,但PUFAs含量（W/W）在10-20℃之间差异不显著（P＞0.05）.虽然等鞭金藻DHA含量随着温度的上升而下降,但PUFAs在20℃时含量（W/W）最高,为10.5%.不同海洋微藻不仅具有不同的生长温度,且最适PUFAs合成的温度也不同.     

ON THE ANALYSIS OF HOP BITTER ACID

A High Performance Liquid Chromatography (HPLC) method for automated routine analysis of the hop bitter acids is described. It allows the simultaneous determination of α-acids, β-acids, cohumulone and colupulone. This analysis based on two chromatographic runs takes less than 1/2 h. With this new method as reference, the defects of existing conductometric titration techniques were studied and a new improved conductometric method based on toluene-buffer extraction was developed. The new methods are applicable to all forms of hop products containing α- and β-acids. Analysis for α-acids with ether-acid aqueous methanol extraction gives results which are too high because of several basic defects.     

不同动物肝脏中脂肪酸成分分析

采用气相色谱法对7种动物肝脏中脂肪酸组成进行分析。以猪、羊、鸡、鸭、鲫鱼、草鱼和鹅的肝脏为材料,采用KOH-乙醇皂化,HCl-甲醇酯化的方法进行样品处理。实验结果表明,猪肝中有16种脂肪酸,鸡肝中有12种脂肪酸,羊肝中有18种脂肪酸,鸭肝中有14种脂肪酸,鲫鱼肝中有20种脂肪酸,草鱼肝中有22种脂肪酸,鹅肝中有19种脂肪酸。能快速、准确、可靠的满足动物肝中脂肪酸检测分析要求。     

THE VALUE OF LONG-CHAIN FATTY ACID COMPOSITION IN THE IDENTIFICATION OF SOME BREWERY YEASTS

The cellular long-chain fatty acids of 72 strains representing 29 species of brewery yeasts were extracted by saponification and analysed as methyl esters by gas chromatography. With this method, it was possible to distinguish between Saccharomyces cerevisiae and five other groups from the brewery industry, only four hours after they were obtained from 48 h old cultures under standard conditions. This compares favourably with the 7 to 10 days for conventional methods.     

ON THE COMPOSITION OF HOP WAX

Hop wax contains free alcohols, free acids, wax esters, hydrocarbons, β-sitosterol and traces of campesterol. The composition of the free alcohols, free acids and wax esters was investigated. Varietal identification of hops based on wax composition is not reliable.     

THE EFFECT OF PRE-ISOMERISED HOP EXTRACT ON THE PROPERTIES OF MODEL PROTEIN STABILIZED FOAMS

A commercial sample of pre-isomerised hop iso-alpha acids was found to increase the stability of foams stabilized by bovine serum albumin or β-lactoglobulin as determined by a conductimetric technique under a variety of solution conditions. Suspended thin films containing hop iso-alpha acids were found to have drainage kinetics and equilibrium thicknesses distinct from control samples. The surface diffusion coefficient of fluorescent-labelled β-lactoglobulin in films partially destabilized by the presence of the non-ionic detergent, Tween 20 was found to be significantly decreased by the presence of hop iso-alpha acids. These findings support the hypothesis that hop acids stabilize foams by crosslinking surface adsorbed proteins.     

粮食脂肪酸值测定方法的研究进展

脂肪酸值是粮食储存品质的重要指标。本文简要介绍提取粮食游离脂肪酸的各种溶剂,对滴定法、比色法和色谱法等粮食脂肪酸值测定方法的优缺点及其研究进展也作了探讨。     

LONG-CHAIN FATTY ACID COMPOSITION AS A CRITERION FOR YEAST DISTINCTION IN THE BREWING INDUSTRY

The diversity of yeasts isolated from brewing plants and its role on beer quality makes yeast distinction a major concern in industrial microbiological control. Several approaches have been tried to develop rapid and simple methods to perform such tasks. Among these, stands the utilization of long-chain fatty acid composition of total yeast biomass. In this paper results are reported showing the potential of this technique to characterize yeast flora isolated from industrial plants. Fatty acid profiles of brewing species are clearly differentiated from those of non-Saccharomyces strains using statistical data treatment by principal component analysis (PCA). Distinction between brewing and wild strains of Saccharomyces spp. was not apparent. In comparison, fatty acid profiling showed higher discriminating ability than growth on lysine medium for non-Saccharomyces strains. For distinction of S. cerevisiae var. diastaticus from other Saccharomyces strains, growth on starch medium showed to be necessary.     

INFLUENCE OF DIETARY MENHADEN FISH OIL ON FATTY ACID COMPOSITION OF THE EGG

The influence of menhaden fish oil and other oils on the fatty acid composition of the egg was studied. Diets containing 1.5% menhaden oil, 1.5% corn oil and no oil added were fed to 50 hens. The menhaden oil diet increased the composition of C_14:0, C_16:1, C_18:1, C_18:3w3, C_20:5w3 and C_22:6w3 in the eggs but decreased C_18:2w6 and C_20:4w6 compared with the corn oil diet. The concentration of C_20:5w3 was greater than C_22:6w3 in menhaden oil, but more C_22:6w3 was found in eggs than C_22:6w3. A significant increase in total w-3 PUFAs (polyunsaturated fatty acids) occurred in the eggs after feeding the menhaden oil diet for 5 days and the concentration continued to increase through day 15. Dietary fats tend to produce a fatty acid pattern in eggs similar to that of the diet and varies with the oil source concentration. Most fatty acid profiles in egg yolks were altered within 15 days after hens began to consume test diets.     

FATTY ACIDS IN ISOMERIZED HOP EXTRACTS AND GUSHING

A procedure is described for the analysis of fatty acids (C₁₂-C₁₈ individually and C₁₈₊ as a group) in hops, hop extracts and isomerized hop extracts, and analytical results are quoted for twenty-one different samples of hops or hop products. Isomerized extracts varied widely in their content of fatty acids and isomerization and processing of hops appeared to eliminate some fatty acids selectively so that isomerized extracts were enriched in palmitic acid, linoleic acid and linolenic acid. Some hop extracts had a surprisingly high content of lauric acid. The analytical results are discussed in relation to gushing.     

德昌水牛乳脂肪酸组成的气相色谱—质谱分析

分析德昌水牛及其杂交后代乳脂肪酸的组成特点.采集德昌水牛及其与尼里拉菲水牛的F1代常乳样品,提取脂肪后进行甲酯化,用气相色谱-质谱联用法测定脂肪酸组成.结果显示,德昌水牛及其F1代乳中的主要脂肪酸为肉豆蔻酸、棕榈酸、油酸、硬脂酸,乳中肉豆蔻酸、棕榈酸比例显著低于F1代,而硬脂酸、油酸比例显著高于F1代.德昌水牛乳脂肪酸组成与牛乳、牦牛乳相比存在一些差异.     

利用餐饮杂油脂肪酸直接氢化生产硬脂酸的工艺研究

论述了餐饮杂油脂肪酸直接加氢的研究意义、工艺优势，以及催化剂、前处理、搅拌、温度等因素对加氢反应的影响。     

储藏过程中小麦粉脂肪酸值变化规律的研究

阐述了5～9月小麦粉在储存过程中脂肪酸值变化规律。以期对此段时间内小麦粉的储藏和保持品质方面提供参考数据,保证安全储藏。     

EFFECT OF FERMENTATION ON THE FATTY ACID CONTENT AND COMPOSITION OF CASSAVA TUBER MEAL

The effect of fermentation on the fatty acids (FA) content and composition of cassava tuber meal has been investigated. The major FA of the cassava tuber meal (CTM) lipid were oleic and palmitic acids. Other FA found in decreasing order were linoleic, linolenic, palmitoleic, stearic, myristic, pentadecanoic, heptadecanoic and nonadecanoic acids. Fermentation of the CTM resulted in substantial increases in the absolute quantities of the individual FA detected except linolenic acid. However fermentation did not alter the pattern of composition of the FA, but it caused increases in the composition of saturated FA and decreases in certain unsaturated ones. Stearic acid increased in composition by about 92.6% and pentadecanoic by about 50%. A reduction of about 72% of the linolenic acid and 24.2% of the palmitoleic acid composition were obtained in the fermented CTM lipid.     

HOP PRODUCTS

Hop products have established an important and permanent position in the brewing raw materials market. Hop pellets and hop extract offer significant advantages to traditional brewers. However, the ultimate hop product is the isomerised hop extract, which can now be produced without the involvement of organic solvents. Still to be resolved and hence controlled is the contribution of the hop oil fraction to beer flavour.     

FATTY ACID COMPOSITION OF THE SEED OIL OF ARUM ITALICUM MILLER

The genus Arum (Araceae) is represented by some 20 taxa in Turkey. Having tuberous roots, broadly hastate vigorous leaves, greenish-yellow spathes A. italicum grows in northern Turkey and flowers between April and May and its reddish berry type fruits ripen in July. Containing significant amount of calcium oxalate crystals, oxalic acid and oxalates in addition to volatile and/or easily destroyed irritating substances , Arum taxa are toxic. However, dried or fresh parts thereof are used for food and in folk medicine in Turkey. Tubers and ripe fruits are used in the treatment of rheumatism and hemorroids while the leaves are consumed as a food. The fatty acid composition of the seed oil of A. italicum oil was investigated by analyzing their methyl esters by GC and GC-mass spectrometry. The major fatty acids were 16:0, 16:1 n-7, 18:0, 18:1 n-9, 18:2 n-6 and 13-phenyltridecanoic acid in the seed oil. This is the first report on fatty acid composition and 13-phenyltridecanoic acid content of Arum italicum Miller seeds from Turkey.