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961.
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963.
鱼油脂肪酸乙酯化工艺研究 总被引:11,自引:0,他引:11
比较三种不同鱼油原料脂肪酸组成、含量和各项品质指标,选取步鱼油用碱催化法进行乙酯化反应。通过单因素实验和响应面分析,步鱼油乙酯化工艺最优条件为:无水乙醇/鱼油反应物摩尔比为6:1,反应温度为75℃~77℃,反应时间2小时,碱催化剂浓度为0.8N~1.0N,由分子蒸馏得到乙酯化得率为96%。 相似文献
964.
Guoliang Li Zhiwei Sun Lian Xia Junyou Shi Yongjun Liu Yourui Suo Jinmao You 《Journal of the science of food and agriculture》2010,90(11):1905-1913
BACKGROUND: Supercritical CO2 was utilised to extract Chinese star anise seed oil (CSASO), and a three‐level Box–Behnken factorial design from response surface methodology was applied to optimise the extraction conditions, including pressure, temperature and amount of modifier (ethanol). The compositional analysis of fatty acids in CSASO was performed by HPLC with fluorescence detection using 2‐(11H‐benzo[a]carbazol‐11‐yl)‐ethyl‐4‐methylbenzenesulfonate (BCETS) as labelling reagent. Identification was carried out by online atmospheric chemical ionisation–mass spectrometry. RESULTS: The optimum extraction conditions were as follows: extraction pressure, 27.72 MPa, extraction temperature, 46.22 °C, and amount of modifier, 8.58 vol.%. The experimental result showed that the maximum extraction yield was 25.31 ± 0.22% (w/w) under the conditions proposed. The compositional analysis indicated that CSASO mainly contained C18:2, C18:1, C18:3, C20:4, C16, C18 and C20 fatty acids. CONCLUSION: In this study, a fast, simple and high‐efficiency supercritical technique for extracting oil from Chinese star anise seed was developed. Simultaneous determination of fatty acids in CSASO using BCETS as the labelling reagent with HPLC fluorescence detection and online mass spectroscopy identification has been successfully achieved. Copyright © 2010 Society of Chemical Industry 相似文献
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966.
葵花籽油模拟液中甲基丙烯酸甲酯迁移量的测定 总被引:1,自引:0,他引:1
目的 建立了葵花籽油模拟液中甲基丙烯酸甲酯迁移量的测定方法。方法 采用乙醇漩涡提取葵花籽油中甲基丙烯酸甲酯2 min, 用GC/MS检测, 外标法定量。结果 本法的定量限(LOQ)为0.75 mg/kg, 线性范围为0.75~30.00 mg/kg, 线性相关系数为0.9998。在1倍LOQ、2倍LOQ、0.5倍限量、1倍限量及2倍限量5个添加水平下平均回收率在86.71%~100.45%之间, 相对标准偏差(n=6)均小于5%。结论 方法的灵敏度、回收率高、选择性好, 能满足实际工作的要求。 相似文献
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968.
通过系列条件试验和对比试验对液氨中油含量的测定方法进行研究,改变其测定原理和操作方法,在保证分析数据准确度的前提下,尽量缩短分析时间、降低分析成本,并建立了液氨中油含量测定新方法,即环己烷萃取比色测定法.通过精密度试验和回收率试验,验证了该测定方法准确可靠,分析时间可缩短约4h. 相似文献
969.
A Blend of Essential Plant Oils Used as an Additive to Alter Silage Fermentation or Used as a Feed Additive for Lactating Dairy Cows 总被引:1,自引:0,他引:1
A blend of essential plant oils was evaluated for its effects on silage fermentation and animal performance. In the first experiment, the blend of essential oils was mixed with freshly chopped whole-plant corn to achieve a concentration of 0, 40, or 80 mg of active product per kilogram of fresh forage weight. Whole-plant corn was also mixed with a buffered propionic acid-based product at 0.2% of fresh forage weight. The blend of essential oils did not affect the populations of yeasts, molds, lactic acid bacteria, or enterobacteria; the fermentation end products; or the aerobic stability of the corn silage. Addition of the buffered propionic acid additive moderately reduced the production of acids during fermentation and resulted in a small reduction in the numbers of yeasts after ensiling, but did not affect aerobic stability. In a second experiment, 30 Holstein cows (4 primiparous and 26 multiparous) averaging 118 ± 70 d in milk and producing 38 ± 16 kg of milk/d were fed a total mixed ration, once daily, that consisted of (on a DM basis) 25% corn silage, 15% alfalfa silage, 10% alfalfa hay, and 50% concentrate. One-half of the cows were fed a blend of essential oils that was mixed directly into their total mixed ration to provide 1.2 g/cow per d for 9 wk. Cows fed the essential oils ate 1.9 kg more dry matter/d and produced 2.7 kg more 3.5% fat-corrected milk/d than did cows fed the control diet. The percentages of milk fat and protein, the somatic cell count numbers, and the concentrations of milk urea nitrogen were unaffected by treatment. Feed efficiency, change in body weight, and change in body condition scoring were also similar between treatments. After 12 h of incubation, the addition of a moderate dose and a high dose of essential oils to in vitro ruminal fermentations had no effect on the concentration of total VFA compared with the control treatment. However, they decreased the molar proportions of acetic, butyric, and valeric acids and increased the proportion of propionic acid. The blend of essential oils evaluated in this study altered in vitro ruminal fermentation and improved animal performance when fed directly to cows, but it did not affect the fermentation or aerobic stability of corn silage. 相似文献
970.