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《食品与发酵工业》2015,(6):76-80
通过在脱脂乳中分别添加不同浓度的亚油酸进行发酵培养,测定发酵后酸奶的酸度、黏度、保水性、活菌数和共轭亚油酸含量,根据这些特征指标来确定亚油酸的最适添加量。结果表明,亚油酸添加量对酸奶的酸度和保水性影响较小,而酸奶的黏度、活菌数和共轭亚油酸的产量均与亚油酸添加量密切相关。当亚油酸添加量小于0.075%时,酸奶的黏度和活菌数随亚油酸添加量的增加而增加,而当亚油酸添加量大于0.075%时,酸奶的黏度和活菌数均逐渐降低。酸奶中共轭亚油酸的含量随亚油酸添加量的增加而增加,随发酵时间的延长呈现先增加后减少的趋势。综合所有结果后发现,当脱脂乳中亚油酸添加量为0.1%,发酵36 h时,酸奶的黏度为2 700 m Pa·s,酸度为80°T,保水性为45%,活菌数为4.0×108CFU/m L,共轭亚油酸含量达到0.9 mg/m L,可获得品质优良且富含共轭亚油酸的酸奶。 相似文献
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葵花籽油混合无水乙醇,通过酶催化得到亚油酸乙酯,以亚油酸乙酯为原料,采用无溶剂碱催化共轭化得到共轭亚油酸乙酯,经皂化酸化得到共轭亚油酸。通过单因素试验得到共轭化过程中最优的反应条件,即反应温度140℃,催化剂用量6%,反应时间2 h。并对共轭亚油酸的含量进行检测,在最优条件下共轭亚油酸C18:2(9c,11t和10t,12c)异构体含量达到63.03%,共轭化转化率97.82%。 相似文献
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在动物性食品中,除了传统的营养价值之外,也含有一些对人体健康和疾病预防具有有益作用的微量成分,CLA(conjugated linoleic acid,共轭亚油酸)就是其中的一个例子。近年来大量的动物实验和细胞培养实验证明了CLA系列的生物学保健功能。 一、CLA的组分 CLA是一组亚油酸的立体异构和位置异构的混合物,在碱存在条件下,亚油酸加热能够产生许多CLA的异构体形式。在牛奶脂肪、奶酪和牛肉中也发现了许多CLA的异构体。然而,9-顺-11-反 CLA是膳食中 CLA的主要存在形式。这种CLA异构体是在牛或其它反刍动物的瘤胃中,亚油酸或亚麻酸被微生物氢化过程中产生的。 相似文献
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研究了牛乳中共轭亚油酸含量的紫外分光光度测定方法。利用紫外分光光度计,先建立标准曲线与回归公式,再将牛奶样品提取、甲酯化后,进行紫外检测。结果表明,共轭亚油酸甲酯的最大吸收波长是234nm;共轭亚油酸浓度的有效测定范围是0.00856-0.0428mg/mL;吸光度与共轭亚油酸浓度间的回归公式为Y=52.602X+0.0917(R2=0.9862);得出共轭亚油酸浓度与吸光度之间的经验公式为:共轭亚油酸浓度C(mg/mL)=0.019×吸光度(ABS);并且推出了利用紫外分光光度法测定牛奶中共轭亚油酸含量的计算公式。同时,检验了几种市售牛奶中共轭亚油酸,其平均含量为1.64mg/g。 相似文献
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牛奶中共轭亚油酸含量的紫外分光光度测定方法 总被引:4,自引:0,他引:4
研究了牛乳中共轭亚油酸含量的紫外分光光度测定方法。利用紫外分光光度计,先建立标准曲线与回归公式,再将牛奶样品提取、甲酯化后,进行紫外检测。结果表明,共轭亚油酸甲酯的最大吸收波长是234nm;共轭亚油酸浓度的有效测定范围是0.00856-0.0428mg/mL;吸光度与共轭亚油酸浓度间的回归公式为Y=52.602X 0.0917(R2=0.9862);得出共轭亚油酸浓度与吸光度之间的经验公式为:共轭亚油酸浓度C(mg/mL)=0.019×吸光度(ABS);并且推出了利用紫外分光光度法测定牛奶中共轭亚油酸含量的计算公式。同时,检验了几种市售牛奶中共轭亚油酸,其平均含量为1.64mg/g。 相似文献
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Declined estrogen levels in women after menopause can cause a number of significant health issues, and various estrogen receptor ligands have been clinically evaluated for postmenopausal treatment. Conjugated linoleic acid (CLA) has been shown to display protective effects against menopausal symptoms such as bone loss and metabolic dysfunctions in both animals and humans. In particular, it inhibits the proliferations of breast and endometrial cancer cells through estrogen receptor α‐mediated mechanism(s). These findings suggest that CLA may provide beneficial effects on menopausal symptoms, while protecting the endometrium and breast from estrogen stimulation. Thus, understanding the effects of CLA on menopausal disorders and ER metabolism is important in development of novel therapeutic options for use in postmenopausal women with or without conventional estrogen therapy. In this report, we review literature regarding the impact of CLA on menopausal symptoms in cell lines, rodents, and humans, along with potential mechanism(s). We also discuss safety consideration for CLA use in humans. 相似文献
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Samples were taken at 9 stages of processing, from raw milk to cheese aged for 6 mo. Fatty acid distributions, conjugated linoleic acid (CLA), moisture, protein, lipid contents, and titratable acidity were determined. CLA contents were highest after 3 mo, with one type of Cheddar (3.76 mg/g lipid) higher than the other two (3.44 and 3.47 mg/g lipid). Multiple linear regression showed all composition parameters were directly related to CLA content (mg/100 g sample). The content of oleic acid isomer C18:1ω7 was also directly related to CLA content (mg/g lipid). Thus, content of CLA in Cheddar-type cheeses might be controlled by stage and conditions of processing. An understanding of the effects of processing on CLA formation in Cheddar-type cheeses will be beneficial in designing processing methods to enhance CLA contents. 相似文献
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Conjugated Linoleic Acid and Fatty Acid Composition of Yogurt Produced from Milk of Cows Fed Soy Oil and Conjugated Linoleic Acid 总被引:1,自引:0,他引:1
ABSTRACT: Yogurt was processed from milk from Holstein cows whose diets were supplemented with soy oil (5%) and/or conjugated linoleic acids (CLA, 1%) to determine the effect of processing and dietary supplementation on CLA and fatty acid composition. Processing and storage for 7 d did not significantly affect CLA or fatty acid composition. CLA contents of milk and yogurt increased 2.8- and 2-fold by soy oil and CLA supplementation, respectively. Contents of saturated fatty acids decreased and trans -octadecenoic acids increased with the soy-oil-supplementation. The addition of CLA to soy-oil-supplemented diets did not significantly affect the CLA and fatty acid composition of the yogurt. 相似文献
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气相色谱法分析共轭亚油酸异构体 总被引:17,自引:0,他引:17
有许多种测定共轭亚油酸各异构体相对含量的方法 ,如气相色谱法、银离子高效液相色谱法、气质联用和核磁共振法等 ,其中气相色谱法最为简便快速。本研究选择气相色谱法用于共轭亚油酸各异构体的分析。结果表明 ,气相色谱法可用于共轭亚油酸中主要异构体的相对含量的测定 相似文献
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共轭亚油酸的生理功能(Ⅰ) 总被引:5,自引:1,他引:4
综述了共轭亚油酸的研究历史和现状,并详细论述了共轭亚油酸的抗癌特性及其癌症的抑制机理,研究表明,共轭亚油酸的抗癌作用可归结为抑制衍生自花生四烯酸的类二十烷合成的能力。 相似文献
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在超临界CO2状态下,采用脂肪酶催化共轭亚油酸(conjugated linoleic acid,CLA)与甘油反应制备共轭亚油酸甘油酯,分别应用单因素和正交试验考察分子筛添加量、酶用量、反应压力、温度和时间对CLA酯化率的影响。结果表明,最佳工艺条件为分子筛用量6%、酶用量4%、反应温度60℃、反应时间20h、反应压力11MPa,此条件下CLA的酯化率可达到90.98%。这种CLA甘油酯的脂肪酸组成中,9c,11t-CLA和10t,12c-CLA的含量分别为37.79%和41.66%。 相似文献