Oxidative stability of natural and randomized high-palmitic-and high-stearic-acid oils from genetically modified soybean varieties

The oxidative stability of soybean oil triacylglycerols (TAG) obtained from genetically modified soybeans was determined before and after chemical randomization. Soybean oil oxidative studies were carried out under static oxygen headspace at 60°C in the dark and oxidative deterioration was monitored by peroxide value, monometric and oligomeric oxidation products, and volatile compounds. Randomization of the soybean oil TAG improved the oxidative stability compared to the natural soybean oil TAG. Oxidative stability was improved by three factors. Factor one was the genetic modification of the fatty acid composition in which polyunsaturated acids (such as linolenic and linoleic acids) were decreased and in which monounsaturated fatty acids (such as oleic) and saturated acids (palmitic and stearic) were increased. Factor two was the TAG compositional modification with a decrease in linolenic and linoleic-containing TAG and an increase in TAG with stearic and palmitic acids in combination with oleic acid. Factor three was the TAG structure modification accomplished by an increase in saturated fatty acids and a decrease in linoleic and linolenic acids at the glycerol moiety carbon 2. Presented at the AOCS Annual Meeting & Expo, Chicago, IL, May 10–13, 1998.     

Properties of Cookies Made with Natural Wax–Vegetable Oil Organogels

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax–VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax–VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats.     

酸水解法与自动索氏抽提法测定人造奶油脂肪含量的差异研究和方法改进

采用酸水解法和自动索氏抽提法测定6种不同人造奶油试样的脂肪含量,并对自动索氏抽提法进行改进,对不同方法的结果差异进行分析和研究。结果表明:酸水解法的实验结果偏低;且酸水解法和自动索氏抽提法对人造奶油脂肪含量的测定存在显著差异,采用自动索氏抽提法更合适。同时,对自动索氏抽提法进行改进,实验结果准确度高,其标准差为0.12,均值标准误差为0.03,说明改进自动索氏抽提法重现性好;且改进法对实验具有显著的影响。采用改进自动索氏抽提法,抽提纸筒可循环使用12次,有效降低了实验成本。     

Comparison of the Dispersed Phase Coalescence Mechanisms in Different Tablespreads

ABSTRACT:  Temperature-induced destabilization of the dispersed phase in butter and margarine was compared by following changes in droplet size ( d _3,3), solid fat content (SFC), and fat crystal spatial organization in the 28–34 °C range. At 28 °C, both butter and margarine were stable, with similar d _3,3 values (approximately 6 μm) and droplet size distributions. As the storage temperature was raised above 30 °C, notable droplet coalescence was observed (for example, at 32 °C d _3,3 values of approximately 10 μm for butter and approximately 12 μm for margarine were obtained). Dispersed phase coalescence in butter was dominated by coagulation, with the fat crystal network-limiting droplet–droplet contact until a minimum SFC was reached (approximately 2.5%). In margarine, the rate-limiting step for coalescence was the melting of Pickering crystals present around the dispersed aqueous droplets. Unlike butter, there was no sharp change in stability at a particular temperature or critical SFC. With these differences, coalescence in butter could be modeled as a 2nd-order process and as a 1st-order process in margarine. Overall, these results demonstrated that the kinetic stability of the dispersed aqueous phase in butter and margarine depends on SFC and the spatial distribution of fat crystals within the spreads.     

搅打型人造奶油稳定性研究

研究以氢化棕榈油为油相主要原料,经配料、乳化、急冷、搅打制成低脂肪搅打型人造奶油,解决了打发后体积不够大、塑性不高及稳定性差等问题;并对奶油的感官品质加以完善,进行了合理的营养强化.     

脂肪替代物在低脂人造黄油中的应用研究进展

人造黄油又称人造奶油,其风味独特,口感细腻,营养价值很高,一直深受消费者的喜爱。但随着人们日益增长的健康意识,食品营养所受到的关注也越来越多。人造黄油脂肪含量较高,经常食用易对人体健康造成损害,单纯减少人造黄油中的脂肪含量会对黄油整体品质造成很大的影响,因此,如何取代人造黄油中的高热量油脂已经成为了热门的研究方向。本文综述了不同基质的脂肪替代物及其在低脂人造黄油中的应用研究,旨在脂肪替代物在低脂人造黄油中的进一步开发研究提供一定的帮助。     

零反式脂肪酸酥皮油基料油的理化性质研究

以猪油、42℃棕榈油、51℃棕榈油和大豆油为基料油复配制备零反式脂肪酸酥皮油,评价了猪油与棕榈油的相容性,以及各复配油脂的甘油三酯组成、晶型、硬度。结果表明:猪油与棕榈油的相容性较差,所以将猪油含量控制在10%。在确保SFC曲线与商业油趋势一致的基础上进行油脂的复配,复配油脂的主要甘油三酯种类相似,且晶型以β'型为主,配方b、c、e在20℃时的硬度约为250 g,适宜于工业上操作,符合零反式脂肪酸酥皮油基料油的性能要求。