Relationship between oxidative stability of vitamin E and production of fatty acids in oils during microwave heating

Effects of microwave heating on the oxidative stability ofd-tocopherols were studied in relation to the production of fatty acids in oils. During microwave heating, the stability of tocopherols decreased in the orderδ>β>γ>α. This order did not depend on the types of ethyl esters of fatty acids or oils present. But, the shorter the chainlength and the lower the degree of unsaturation of the fatty acid ethyl esters, the greater was the reduction in amount of individual tocopherols. A similar tendency was observed when tocopherol-stripped vegetable oils, with equimolar mixtures of tocopherols added, were treated under the same conditions. The reduction in tocopherols became greater with increasing levels of free fatty acids.     

Retardation of volatile aldehyde formation in the exhaust of frying oil by heating under low oxygen atmospheres

Volatile aldehydes were generated in the exhaust of high-oleic safflower oil during heating at 180°C by spraying water into atmospheres with four levels of oxygen concentrations (2, 4, 10, and 20%). These aldehydes were quantitatively analyzed by HPLC after the conversion to 2,4-dinitrophenyl hydrazones. Ten alkanals (C₂ through C₁₀), eight 2-alkenals (C₃ through C₁₀) and three 2,4-alkadienals (C₇, C₉, and C₁₀) were found. These aldehyde levels were found to be positively correlated with both the heating time and the atmospheric oxygen concentration. The total amounts of aldehydes were the lowest in the oil heated in an atmosphere with 2% O₂, and corresponded to 1/10 of those in the atmosphere with 20% O₂. Acrolein was not found in oils heated in the atmosphere with 2% oxygen. These results suggest that frying in atmospheres with low oxygen levels can effectively decrease the generation of volatile aldehydes in the exhaust.     

假单胞菌多糖为壁材微胶囊的制备

对以明胶和假单胞菌PT-8胞外多糖为壁材制备红花油微胶囊的影响因素进行了研究,包括壁材质量浓度、交联剂质量分数、交联时间、壁材质量比、pH。通过单因素试验和正交试验确定最佳制备条件为:壁材质量浓度为50g/L,交联剂质量分数为3%,交联时间为140min,壁材质量比为5∶4,pH为3.6,此条件下微胶囊的包埋率为81.12%。经显微镜观察发现,微胶囊形态圆整,粒径均匀,分散性较好,粒径在1~10μm。假单胞菌PT-8胞外多糖可以作为制备红花油微胶囊的壁材。     

浙江红花山茶油的原料性状及品质分析

红花山茶油是具有高单不饱和脂肪酸含量和丰富活性物质的特有茶油品种。采集浙江代表性红花山茶籽11种,分析出仁率和籽仁常规营养指标等原料性状,并通过超临界CO_2法萃取山茶油进行脂肪酸组成以及活性物质含量测定。结果表明,干基籽仁粗脂肪为57.31%～68.78%,粗蛋白6.92%～10.64%,总糖质量分数20.41%～28.90%;超临界萃取红花山茶油的油酸质量分数为81.93%～84.42%,不饱和脂肪酸质量分数为87.81%～89.88%,α-维生素E为36.23～58.46 mg/100 g、角鲨烯为16.80～53.56 mg/100 g、茶多酚为43.44～76.76μg/g、茶皂素为2.36～4.86 mg/g。浙江红花山茶籽仁粗脂肪均值,油中油酸质量分数和茶多酚含量均高于普通山茶油,其中油酸质量分数优于其他品种红花山茶油;通过灰色关联度法分析浙江红花山茶籽性状、油品质指标得到最优的采样地均为常山县芳村镇。     

超声波辅助水酶法提取红花籽油的工艺研究

为了提高红花籽油的提取率,通过响应面分析法优化超声波辅助水酶法提取红花籽油的工艺。在单因素试验基础上,选择超声提取温度、超声时间、超声功率为自变量,以红花籽油提取率为响应值,通过BoxBenhnken的中心组合方法进行三因素三水平的试验设计,并进行响应面分析。结果显示:最佳超声预处理条件为超声提取温度41℃,超声时间为49 min,超声波功率为420 W,红花籽油提取率达92.70%;通过方差分析,得到红花籽油提取率与超声处理各因素变量的二次回归方程模型,且该模型回归极显著,对试验拟合较好。     

Preparation of conjugated linoleic acid from safflower oil

Synthetically prepared mixtures of conjugated linoleic acid (CLA) are widely used in animal and cell culture studies to investigate the potential effects of the Δ9c, 11t-18:2 isomer found in food products from ruminant animals. Alkali isomerization of linoleic acid is a common method used in the synthesis of a mixture of CLA isomers containing predominantly the Δ9c, 11t-18:2 and Δ10t, 12c-18:2 isomers. Some biological activity might also be mediated by the Δ10t, 12c-18:2 isomer. Currently few published methodologies exist describing procedures for the enrichment of these two isomers. A method is described herein to take advantage of an inexpensive oil, safflower oil, for use in synthesis of CLA and a procedure to enrich the Δ10t, 12c-18:2 isomer.     

红花细胞和组织培养研究进展

红花是重要的油药两用作物,本文对红花细胞和组织培养的国内外研究进展进行了综述,主要包括愈伤组织的诱导、次生代谢产物的合成及细胞的大规模培养、器官发生、体细胞胚胎发生等几个方面,并对该领域的发展前景进行了展望.     

改性方式对红花籽粕可溶性膳食纤维理化性质和吸附特性的影响

为改善红花籽粕可溶性膳食纤维的部分理化性质和其吸附特性,以红花籽粕为原料,分别考察碱-酶法、酶-高温蒸煮法、碱-高温蒸煮法3种不同改性方式对其可溶性膳食纤维（SDF）的持水力、膨胀力、持油力等部分理化性质及对葡萄糖、阳离子、胆固醇和亚硝酸根离子吸附能力的影响。结果表明,碱-高温蒸煮法优于其他两种方法,碱-高温蒸煮法改性的红花籽粕SDF的持水力、膨胀力和持油力最佳,分别为5.58 g/g、3.98 mL/g和4.38 g/g;对葡萄糖吸附能力为16.08 mmol/g,在1% NaOH添加量为1～4 mL时,阳离子吸附效果最佳;在pH为2和7时,对胆固醇吸附能力分别为7.68 mg/g、10.14 mg/g,对亚硝酸盐吸附能力为56.43 μg/g、30.53 μg/g。     

Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria

Plant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the β‐carotene bleaching test (BCBT), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH^?) radical scavenging method and static headspace gas chromatography (HS‐GC) and compared with the antioxidant activity of two reference compounds of different polarity, viz butylated hydroxytoluene (BHT) and rosmarinic acid. The pure reference compounds were applied in a ten‐times lower concentration than the plant extracts. The highest antioxidant activity in the BCBT, close to that of BHT, was observed for the more apolar extracts. The inhibitory effect on β‐carotene bleaching of the polar extracts and rosmarinic acid was much lower than that of BHT. The inhibition of hexanal formation in bulk safflower oil by most of S syriaca and S scardica extracts was as effective as BHT but less so than rosmarinic acid. S montana extracts showed weak antioxidant or even pro‐oxidant properties. Extracts from butanol and from ethyl acetate and the total methanol extracts from all Sideritis plants studied showed a strong radical scavenging activity against DPPH^?, close to that of rosmarinic acid. S montana extracts were, as a whole, slightly weaker radical inhibitors than the extracts from the other two species. The antioxidant activity of Sideritis extracts was attributed to the presence of flavonoid and phenylpropanoid glycosides. Copyright © 2003 Society of Chemical Industry     

红花油衍生多元醇的合成

用两步法合成出绿色化学品红花油衍生多元醇，即蔗糖酯。通过正交实验以及对各影响因素的考察，优选出了酯交换反应的最佳合成方案。蔗糖：红花油乙酯=1：0．8（mol：m01），皂用量15％，催化剂用量为2％，反应温度135℃，反应时间2h，压力≤5mmHg。通过对产物进行TLC分析，表明产物主要为红花油蔗糖单酯、二酯。采用红外光谱对产物结构进行表征。反应收率为60％。