为考察重量法与国际公认的美国分析化学家协会(Association of Official Analytical Chemists,AOAC)方法在测定抗性淀粉含量时能否互换,选择日常生活中常见的8种含淀粉零食和课题组研发生产的玉米回生淀粉Ⅰ、玉米回生淀粉Ⅱ、含醇溶蛋...为考察重量法与国际公认的美国分析化学家协会(Association of Official Analytical Chemists,AOAC)方法在测定抗性淀粉含量时能否互换,选择日常生活中常见的8种含淀粉零食和课题组研发生产的玉米回生淀粉Ⅰ、玉米回生淀粉Ⅱ、含醇溶蛋白玉米回生淀粉、分别添加了40%和80%含醇溶蛋白玉米回生淀粉的馒头共13种样品,分别采用重量法和AOAC法检测其中抗性淀粉含量。结果表明,含油脂的样品测定抗性淀粉含量前需要先去除油脂,所有样品测定前需要脱除水分。当样品油脂或水分含量超过30%时,采用重量法测定抗性淀粉含量与AOAC法测定结果误差会大于5%,其它样品采用重量法测定的结果相对标准偏差均在5%以下。因此,在无脂肪添加的淀粉乳体系、油脂或水分含量低于30%的食品样品中可以用重量法替代AOAC法测定样品中抗性淀粉的含量。展开更多
建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质...建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。展开更多
A method for the preparation and identification of fumitremorgin B-hemisuccinatecarrier protein is described. The overall yield of the fumitremorgin B-hemisuccinate (FTBS) after final purification was 78.6%. The FTBS ...A method for the preparation and identification of fumitremorgin B-hemisuccinatecarrier protein is described. The overall yield of the fumitremorgin B-hemisuccinate (FTBS) after final purification was 78.6%. The FTBS was characterized by UV, IR, EIMS,element analysis, and 1H, 13C NMR. IR was also used to determine the formation of complete antigen complexes. The reaction route was analysized.展开更多
In order to add value to potato peels and also curb their environmental pollution problems, this study investigated the protein enrichment of potato peels with Saccharomyces cerevisiae via Solid-State Fermentation (SS...In order to add value to potato peels and also curb their environmental pollution problems, this study investigated the protein enrichment of potato peels with Saccharomyces cerevisiae via Solid-State Fermentation (SSF). SSF is a fermentation process which involves solid matrix and is carried out in absence or near absence of free water. SSF of potato peel mashed was carried out with S. cerevisiae at 30°C, pH of 5.5, moisture adjustment between 40 and 90%, addition of ammonium sulphate and urea salts as nitrogen supplements for the microorganisms for 3 days. The results showed that the percentage crude protein content of all the fermented samples increased significantly when compared with the unfermented sample. 40% moisture content adjustment and ammonium sulphate as nitrogen source gave the best result. The crude protein increased from 12.5% to 21.86%, which is 74.88% increment for ammonium sulphate supplementation, and 12.5% to 18.42%, which is 47% increment for urea supplementation. Therefore, the fermented peels could serve as good source of cheap protein enriched feed for livestock.展开更多
文摘为考察重量法与国际公认的美国分析化学家协会(Association of Official Analytical Chemists,AOAC)方法在测定抗性淀粉含量时能否互换,选择日常生活中常见的8种含淀粉零食和课题组研发生产的玉米回生淀粉Ⅰ、玉米回生淀粉Ⅱ、含醇溶蛋白玉米回生淀粉、分别添加了40%和80%含醇溶蛋白玉米回生淀粉的馒头共13种样品,分别采用重量法和AOAC法检测其中抗性淀粉含量。结果表明,含油脂的样品测定抗性淀粉含量前需要先去除油脂,所有样品测定前需要脱除水分。当样品油脂或水分含量超过30%时,采用重量法测定抗性淀粉含量与AOAC法测定结果误差会大于5%,其它样品采用重量法测定的结果相对标准偏差均在5%以下。因此,在无脂肪添加的淀粉乳体系、油脂或水分含量低于30%的食品样品中可以用重量法替代AOAC法测定样品中抗性淀粉的含量。
文摘A method for the preparation and identification of fumitremorgin B-hemisuccinatecarrier protein is described. The overall yield of the fumitremorgin B-hemisuccinate (FTBS) after final purification was 78.6%. The FTBS was characterized by UV, IR, EIMS,element analysis, and 1H, 13C NMR. IR was also used to determine the formation of complete antigen complexes. The reaction route was analysized.
文摘In order to add value to potato peels and also curb their environmental pollution problems, this study investigated the protein enrichment of potato peels with Saccharomyces cerevisiae via Solid-State Fermentation (SSF). SSF is a fermentation process which involves solid matrix and is carried out in absence or near absence of free water. SSF of potato peel mashed was carried out with S. cerevisiae at 30°C, pH of 5.5, moisture adjustment between 40 and 90%, addition of ammonium sulphate and urea salts as nitrogen supplements for the microorganisms for 3 days. The results showed that the percentage crude protein content of all the fermented samples increased significantly when compared with the unfermented sample. 40% moisture content adjustment and ammonium sulphate as nitrogen source gave the best result. The crude protein increased from 12.5% to 21.86%, which is 74.88% increment for ammonium sulphate supplementation, and 12.5% to 18.42%, which is 47% increment for urea supplementation. Therefore, the fermented peels could serve as good source of cheap protein enriched feed for livestock.
