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排序方式: 共有1381条查询结果,搜索用时 15 毫秒
1.
Nicolette Pegels Isabel González Irene Martín María Rojas Teresa García Rosario Martín 《Food Control》2011,22(8):1189-1196
A TaqMan real-time polymerase chain reaction (PCR) method was developed for specific detection of bovine, ovine and caprine processed animal protein (PAP) in industrial feedstuffs. The method uses species-specific primers and probes targeting short mitochondrial D-loop sequences, and a positive amplification control based on 18S rRNA gene. The applicability of the real-time PCR protocol was assessed through analysis of 126 industrial feed samples that were manufactured to reproduce rendering processes of commercial feeds destined for farmed animals. The assay successfully classified samples as positive or negative according to the ruminant composition, enabling qualitative detection of banned material in feeds at levels as low as 0.1%. Although the method provides quantitative potential, results suggest that the real quantitative capability of the assay is limited by the existing variability in terms of composition and processing treatments of the feeds, which affect the amount and quality of amplifiable DNA. 相似文献
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Nowadays the increasing interest to perform machining operations is in dry/near-dry environments. The reason includes health and safety of operator, cost, ease of chip recyclability, etc. However one important process, which is difficult to perform in dry, is drilling. Without coolant, drilling leads to excessive thermal distortion and poor tool life. In order to tackle these conflicting requirements, the essentiality of study on machining performances with minimum quantity lubricant (MQL) becomes important.Fuzzy logic rules, which are derived based on fuzzy set theory, are used to develop fuzzy rule based model (FRBM). The performance of FRBM depends on two different aspects: structures of fuzzy rules and the associated fuzzy sets (membership function distributions, MFDs). The aim of this study is to investigate the performances of FRBMs based on Mamdani and TSK-types of fuzzy logic rules with different shapes of MFDs for prediction and performance analysis of machining with MQL in drilling of aluminum alloy. A comparison of the model predictions with experimental results and those published in the literature shows that FRBM with TSK-type fuzzy rules describes excellent trade-off with experimental measurements. 相似文献
3.
Preparation and properties of phytosterols with hydroxypropyl β-cyclodextrin inclusion complexes 总被引:1,自引:0,他引:1
In order to enhance the solubility and bioavailability of phytosterols (PS), cyclodextrin–PS (CD–PS) inclusion complexes were prepared and the properties of PS-β-cyclodextrin (PS-β-CD) and the inclusion mechanism of its derivative hydroxypropyl β-cyclodextrin (PS-HP-β-CD) in solution were also evaluated. The effects of crucial parameters on cyclodextrin–sterol inclusion efficiency were optimized, including solvent type, β-CD/PS molar ratio, temperature, PS content and reaction time; 92–98?% inclusion efficiency was achieved under the conditions of HP-β-CD/PS ratio 3:1–4:1, PS concentration 15–20?mM, temperature 50–55?°C, reaction time 12?h. For β-CD host, butanol was a good solvent for PS inclusion reaction. The properties of CD–PS inclusion complexes were characterized by differential scanning calorimetric, scanning electron microscopy, UV–Vis scanning spectrophotometer (UV–Vis) and fourier transform infrared spectroscopy (FT-IR), which demonstrated that there are intermolecular hydrogen bonds between PS and HP-β-CD in inclusion complex, resulting in the formation of amorphous form. To clarify the mechanism of the increase in the solubility and bioactivity of HP-β-CD–PS inclusion complexes, the structure of CD as well as the interaction of the HP-β-CD–PS inclusion formation was elucidated. The conclusions indicated that PS-HP-β-CD showed higher water solubility with greater solubilizing and complexing capabilities than PS-β-CD and PS itself. 相似文献
4.
Chunhua Wu Yuan Li Liping Wang Yaqin Hu Jianchu Chen Donghong Liu Xingqian Ye 《Food and Bioprocess Technology》2016,9(4):675-685
The synergistic effect of gallic acid (GA) and chitosan (CS) as edible coatings on the quality and shelf life of Pacific mackerel (Pneumatophorus japonicus) fillets during chilled storage was investigated in this study. Pacific mackerel fillets were periodically evaluated to assess their microbiological (total viable count), physicochemical (pH, total volatile basic nitrogen, biogenic amine, thiobarbituric acid, and K value), and sensory characteristics. The results indicated that CS?+?GA was more effective than either treatment alone in inhibiting microbial growth, protein decomposition, biogenic amine formation, lipid oxidation and nucleotide breakdown, and maintaining better sensory characteristics during storage, thereby extending the shelf life of mackerel by 6 days compared with the control group. Therefore, a coating with the combination of chitosan with GA represents a promising method for maintaining the storage quality of Pacific mackerel fillets and has broad potential applications in the seafood industry as a food-grade biopreservative. 相似文献
5.
Nadide Seyhun Hosahalli S. Ramaswamy Songming Zhu Gulum Sumnu Serpil Sahin 《Food and Bioprocess Technology》2013,6(11):3200-3205
Frozen potato puree samples were tempered using an ohmic heating technique. Three salt concentrations (0.50, 0.75, and 1.00 %) and three frequency levels (10, 20, and 30 kHz) were used as experimental variables, and the effects of salt concentration and frequency on ohmic tempering were investigated. Temperature, electrical current, and voltage were measured during the ohmic tempering. Electrical conductivities were evaluated based on the sample geometry and the ohmic heating principle. Increasing the salt concentration and/or frequency increased the electrical conductivity and heating rate, and hence contributed to decreasing the tempering time for the frozen potato puree samples. The tempering time was lowest with the highest salt concentration employed, and longest for the lowest salt concentration and frequency. Temperature differences within the sample during ohmic heating were found to be lowest when employing 0.50 % salt concentration and 10 kHz frequency. 相似文献
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目的:寻求合适工艺提取枇杷花叶中的总三萜酸、总黄酮、多糖,并研发枇杷花叶提取物压片糖果制备的最优配方工艺。方法:枇杷花、叶洗净烘干,用搅拌机粉碎、过筛,采用分步法提取花叶(1:1,g/g)中总三萜酸、总黄酮和多糖,以单因素实验法确定其合适的提取工艺参数;在单因素实验基础上,采用正交实验(L9(33))优化枇杷花叶提取物压片糖果的工艺配方。结果:总三萜酸提取的合适工艺为100%乙醇、料液比1:40(g/mL)、提取温度50 ℃、提取时间2 h,粗提物得率为1.6%;总黄酮提取的合适工艺为60%乙醇、料液比1:20(g/mL)、提取温度50 ℃、提取时间2 h,粗提物得率为17.9%;多糖水提的合适工艺为料液比1:15(g/mL)、提取温度80 ℃、提取时间2 h,粗提物得率为1.0%。枇杷花叶提取物压片糖果的最优配方为:枇杷花叶提取物(总三萜酸:总黄酮:多糖=2:18:1,g/g/g)0.2 g、填充剂(微晶纤维素:预胶化淀粉=1:1,g/g)7.5 g、调味剂(木糖醇:柠檬酸=50:1,g/g)5.0 g、硬脂酸镁1%。结论:文章所涉及的提取... 相似文献
9.
Hao Wu John Shi Sophia Xue Yukio Kakuda Dongfeng Wang Yueming Jiang Xingqian Ye Yanjun Li Jayasankar Subramanian 《LWT》2011,44(10):2032-2039
Peach kernel oil was extracted using Soxhlet extraction with different solvents (petroleum ether, ethyl ether, chloroform and hexane). The physicochemical properties (acid value, iodine value, peroxide value and saponification value), the fatty acid composition, phenolic constituents and contents, and antioxidant activities of peach kernel oil were examined. As per our results, oil extracted with hexane has better overall quality. Its acid, peroxide, iodine and saponification values were 0.895 mg KOH/g oil, 0.916 mg/g oil, 36.328 mg/100 g oil and 101.836 mg KOH/g oil, respectively. Large proportions of unsaturated fatty acid (91.27%) and high content of phenolic compounds (4.1593 mg GAE/g), which contribute to considerably strong antioxidant activity, were found in oil. The main fatty acids found in the peach kernel oil were oleic acid (61.87 g/100 g oil) and linoleic acid (29.07 g/100 g oil). The HPLC analysis of phenolic compounds showed that rutin, (-)-epicatechin gallate, hydrocinnamic acid, sinopinic acid, dithiothreitol and caffeic acid were major constituents. The results suggested that peach kernel oil is a good source of the unsaturated fatty acid, phenolic compounds with strong antioxidant activity, and has the potential to be used as nutrient rich food oil. The results also verified that peach kernel meals contained higher amounts of total phenolic and stronger antioxidant activities than oils, enabling their application as ingredients for functional or enriched foods. 相似文献
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