荧光法测定食品中的维生素E——多因素正交试验的应用尝试

<正>维生素E,又称生育酚。属于酚类化合物,共有八种异构体,α、β、γ、δ生育酚和α、β、γ、δ生育三烯酚。其中α-生育酚的生物活性最高。维生素E广泛存在于动物脂肪、脏器、植物油料、谷物和绿叶植物中。     

花家怡园 京味儿年宴暖人心

正"小孩小孩你别馋;过了腊八就是年;腊八粥,喝几天;哩哩啦啦二十三;二十三、糖瓜黏;二十四、扫房日;二十五、炸豆腐;二十六、炖羊肉;二十七、杀公鸡;二十八、把面发;二十九、蒸馒头;三十晚上熬一宿;除夕的饺子年年有。"小孩小孩你别馋;过了腊八就是年;腊八粥,喝几天;哩哩啦啦二十三;二十三、糖瓜黏;二十四、扫房日;二十五、炸豆腐;二十六、炖羊肉;二十七、杀公鸡;二十八、把面发;二十九、蒸馒头;三十晚上熬一宿;除夕的饺子年年有。"一首简单的民谣,几乎道尽了老北京人过年的所有习俗。不用山珍海味,不用     

茶叶卫生质量调查分析

<正>茶叶是人们喜爱的饮料。徽州地区是我国重要的产茶基地之一,盛产名茶“祁红”、“屯绿”、“黄山毛峰”、“太平猴魁”、“老竹大方”、“松萝茶”、“黄山花茶”。为了解茶叶卫生质量,验证国家茶叶卫生标准可行性,我们对全区生产茶叶进行卫生调查,现将结果报告如下。     

西青果中化学元素的测定研究

西青果样品经微波消解后,以ICP-MS/ICP-AES法联合测定其中的24种元素,方法的准确性用国家一级标准物质GBW10015、GBW10020进行对归照分析。检测结果显示,本方法检出限低,准确度高,精密度好,完全可以满足样品中元素含量测定要求。从检测结果来看西青果中富含K、Mg、Ca、P等宏量元素及Fe、Zn、Mn、Cu等微量元素,其中K含量最高为11100μg/g,而Be、Cd、Mo、Tl含量较低,均低于0.3μg/g。所测定元素的含量顺序依次为K>Ca>Mg>P>Al>Fe>Ti>B>Na>Zn>Mn>Cu>Sr>Ba>Ni>V>Cr>Pb>Co>Li>Mo>Cd>Be>Tl。     

聚类法分析不同品种树莓的加工特性

以15 个不同品种的树莓鲜果为实验材料,对果实的组成分、理化指标、VC、粗蛋白、总酚和花色苷含量进行测定分析。通过聚类分析,筛选出适合不同树莓产品加工的品种。结果表明：不同品种树莓的硬度值、果实出汁率、可溶性固形物含量、可滴定酸含量、糖酸比差异较大,硬度值在18.20～49.50 g之间,‘Cuthbert’硬度值最小（18.20 g）,硬度值最大的为‘米克2号’（49.50 g）,出汁率分布变幅为58.27%～79.80%,其中‘Cuthbert’出汁率最低（58.27%）,出汁率最高的为‘Creston’（79.80%）。可溶性固形物含量在6.86%～10.60%之间,可溶性固形物含量最高的为‘Cuthbert’（10.60%）,最低的为‘菲尔杜德’（6.86%）。糖酸比最大的为‘Sunrise’（7.42）,‘Willamette’糖酸比值最小（1.75）。15 个树莓品种的多酚氧化酶、过氧化物酶的活性和色泽稳定性差异较大。VC含量在6.86～10.60 mg/100 g之间;粗蛋白含量分布变幅为0.70～1.49 g/100 g;总酚含量在1.41～3.44 g/100 g之间。花色苷含量介于72.35～393.88 mg/100 g之间。初步评价：第1类的‘Rideau’、‘米克1号’和‘米克2号’,适合于果汁、果酒类产品的加工;‘Zeva Remontant’、‘Nova’适合树莓罐头类产品加工;适合加工果脯类产品的‘Willamette’、‘Omet’、‘Festival’和‘Sunrise’为第2类。‘Rideau’、‘米克1号’、‘米克2号’、‘Willamette’、‘Sunrise’和‘Nova’这6 个品种果实综合品质比较好,是适合于进一步树莓栽培品种选育和深加工的良好品种。     

3 个菠萝品种果实香气成分分析

研究“巴厘”、“卡因”和“台农11 号”3 种菠萝果实的香气成分及其差异。采用顶空固相微萃取技术- 气质联用技术(HS-SPME-GC-MS)对3 种菠萝成熟果实香气成分进行分析测定。从 “巴厘”、“卡因”和“台农11 号”3 种果实中分别检测出46、40 和29 种香气成分,各占总峰面积的99.04%、84.11%、92.43%。主要成分为酯类、烃类、苯类、萘类化合物。酯类物质在“巴厘”“卡因”“台农11 号”测试品种中含量最高,分别达90.87%、59.92% 和82.54%;烃类次之,苯类和萘类物质含量较小。3 种果实有11 种相同的香气成分,独有的香气成分为：“巴厘”16 种,“卡因”16 种,“台农11 号”7 种。3 种菠萝果实香气成分的种类和含量之间存在差异,“巴厘”的重要特征香气成分为癸酸乙酯、己酸乙酯和2- 甲基丁酸乙酯;“卡因”的重要特征香气成分为己酸乙酯、辛酸乙酯和乙酸异戊酯;“台农11 号”的重要特征香气成分为己酸乙酯、辛酸乙酯和2-甲基丁酸乙酯。     

2021年新乡市一起山夫登堡沙门菌食物中毒分离株的病原特征分析

目的 分析2021年新乡市一起山夫登堡沙门菌食物中毒分离株的病原特征。方法 对食物中毒事件进行流行病学调查;对采集的11份样本进行致病菌分离鉴定;对分离出的10株沙门菌进行血清学分型、药敏试验、5种毒力岛（SPIs）特征基因片段（mogA、sseL、mgtC、bcfA、araB）检测及脉冲场凝胶电泳（PFGE）分型分析。结果 10株沙门菌血清抗原式均为1,3,19;g,s,t,即山夫登堡沙门菌。10株沙门菌对头孢唑啉、卡那霉素、庆大霉素、阿米卡星的耐药率为100%,其中从患者粪便中分离出的2株对氨苄西林、四环素、多西环素、氯霉素、复方新诺明的耐药率为100%。PFGE图谱聚类分析显示,10株菌（2株病例株,5株食品株,3株环境株）之间条带无差异,高度同源。10株菌中5种毒力岛特征基因片段均检出。结论 本起食物中毒事件致病因子为山夫登堡沙门菌,该菌携带5种毒力岛特征基因片段,2株病例株沙门菌具有多重耐药性,建议相关部门高度关注。     

铜、锌、铁在皮蛋加工中作用差异研究

分析了“铜法”、“锌法”、“铁法”、“铜锌混合法”、“铁锌混合法”加工皮蛋过程中料液中铜、锌、铁浓度及OH―浓度的变化,同时检测各种方法加工皮蛋产品的质量。结果表明,锌在料液中溶解度最大,其浓度随加工进程无明显降低,“锌法”所得产品易出现“烂头”现象;铜溶解度次之,其浓度随加工进程稳步降低,“铜法”所得产品质量优良;铁溶解度最小,其浓度随加工进程稍有降低,“铁法”很难得到合格产品;“铁锌混合法”和“铜锌混合法”也能较好控制产品质量。     

人参果汁浓缩液对环磷酰胺诱导免疫抑制小鼠免疫功能的影响

目的 研究人参果汁浓缩液对环磷酰胺致小鼠免疫损伤的作用及其可能机制。方法 将72只SPF级雄性C57BL/6J小鼠随机分成空白对照组、环磷酰胺组、阳性药物组、人参果汁浓缩液低、中、高剂量组（83、166、249 mg/kg）,每组12只。第1~14天,人参果汁浓缩液3个剂量组小鼠灌胃相应的人参果汁浓缩液,空白对照组和环磷酰胺组小鼠灌胃等量的水;第1~7天,阳性药物组小鼠灌胃等量的水,第8~14天,阳性药物组小鼠灌胃20 mg/kg盐酸左旋咪唑（LH）;第12~14天,环磷酰胺组、阳性药物组和人参果汁浓缩液各剂量组小鼠腹腔注射80 mg/kg环磷酰胺,空白对照组腹腔注射等量的生理盐水。实验结束后,计算小鼠脾脏指数、测定小鼠外周血白细胞（WBC）、淋巴细胞（LYM）和LYM%以及检测小鼠血清和脾脏中乳酸脱氢酶（LDH）和酸性磷酸酶（ACP）活性、小鼠脾脏中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性和丙二醛（MDA）含量。结果 各组小鼠体质量比较,差异无统计学意义（P>0.05）。与空白对照组比较,环磷酰胺组小鼠脾脏指数降低（P<0.01）、外周血WBC、LYM和LYM%降低（P<0.05）、血清和脾脏中ACP活性降低（P<0.05）或呈降低趋势、脾脏中SOD、CAT活性降低、MDA含量升高（P<0.05）;与环磷酰胺组比较,人参果汁浓缩液各剂量组脾脏指数升高（P<0.05,P<0.01）、人参果汁浓缩液低、高剂量组LYM%升高（P<0.05）、人参果汁浓缩液各剂量组血清和脾脏组织中ACP活性呈升高趋势或升高（P<0.05）、人参果汁浓缩液低剂量组SOD和CAT活性呈升高趋势、人参果汁浓缩液各剂量组MDA含量降低（P<0.05,P<0.01）。结论 人参果汁浓缩液在一定程度上可改善环磷酰胺引起的小鼠免疫损伤作用,可能与减轻小鼠免疫器官氧化损伤作用相关。     

书刊装订领域添新秀——紫宏公司SK20书刊包装机简介

近几年,随着竞争的日益加剧,多品种、多批次、按单生产、交货期短的生产特点日益明显,传统的手工书刊包装方式已不适应这一生产模式的要求,为此,上海紫宏机械有限公司开发出了SK20书刊包装机。它由书刊输送部分,供纸部分、主机部分、贴标部分构成,主要适用于115mm&#215;185mm、148mm&#215;210mm、185mm&#215;230mm、210mm&#215;297mm四种书刊的包装。     

乳清产品在冰淇淋和冷冻乳制品甜食中的应用

<正> 乳清和乳清蛋白产品在过去的60多年中已经被成功应用于冰淇淋和其他冷冻乳制品甜食中。甜乳清、乳清浓缩蛋白(蛋白质含量34～89%)和乳清分离蛋白(蛋白质含量≥90%)是最常用的乳清产品。其他的乳清配料,如脱乳糖乳清和脱盐乳清也是常用的配料。成本优势和提升产品质量是使用乳清产品的主要出发点,     

Chemical composition of urea-treated corn silage containing added dried whey or whey products

Dried whole whey, partially delactosed whey, or lactose were added at two percents (1 and 2% dried whole whey equivalent) to corn silage and .5% urea-treated corn silage and .5% urea-treated corn silage in laboratory silos. Additions of whey products reduced nonprotein nitrogen and ammonia nitrogen in urea-treated corn silage. Dried whey was most effective in reducing ammonia nitrogen while lactose was least effective. This reduction in ammonia nitrogen with no change in total nitrogen indicated that additions of whey products to urea-treated corn silage may have added to the corn silage. Amount of addition of whey products did not influence results. Acid detergent fiber was slightly reduced by all additions and was lowest in corn silages with added lactose. Lactic acid, acetic acid, and pH were higher in corn silages containing urea but were not affected by additions of whey products.     

Plasmin levels in fresh milk whey and commercial whey protein products

Growth of psychrotrophic bacteria in nonfat dry milk at refrigeration temperatures was shown previously in our laboratory to cause a shift in plasmin (a native milk protease) from the casein to the whey fraction. The whey fraction from cheesemaking is commonly used to make whey protein concentrates and isolates, which then are used as functional ingredients in various food systems. Plasmin activity in whey protein products may cause breakdown of food proteins to have desirable or undesirable effects on food quality. This raised questions about the level of plasmin in commercial whey protein products and factors that affect this plasmin level. Therefore, the objectives of this study were to determine: 1) plasmin concentrations in sweet and acid whey protein products as influenced by Pseudomonas growth during storage of fresh milk, and 2) plasmin concentrations in commercial whey protein products. Whey type (sweet or acid) had a significantly (P < 0.05) greater effect on whey-associated plasmin activity than did Pseudomonas fluorescens M 3/6 growth. Acid whey protein products had significantly (P < 0.05) higher plasmin concentrations than sweet whey. Plasmin activities associated with acid and sweet whey protein products were both significantly (P < 0.0001) affected by the growth of Pseudomonas fluorescens M 3/6. The interaction effect between bacterial growth and whey type on plasmin activity was not significant (P = 0.2457). Plasmin activity in the reconstituted commercial whey protein concentrates (i.e., sweet and acid) varied considerably (16.3 to 330 micrograms/g of protein), but was significantly lower (2.1 to 4.4 micrograms/g of protein, P < 0.05) in whey isolates. These quantitative data were supported by plasmin activity visualized by casein SDS-PAGE.     

Invited review: Whey proteins as antioxidants and promoters of cellular antioxidant pathways

Oxidative stress contributes to cell injury and aggravates several chronic diseases. Dietary antioxidants help the body to fight against free radicals and, therefore, avoid or reduce oxidative stress. Recently, proteins from milk whey liquid have been described as antioxidants. This review summarizes the evidence that whey products exhibit radical scavenging activity and reducing power. It examines the processing and treatment attempts to increase the antioxidant bioactivity and identifies 1 enzyme, subtilisin, which consistently produces the most potent whey fractions. The review compares whey from different milk sources and puts whey proteins in the context of other known food antioxidants. However, for efficacy, the antioxidant activity of whey proteins must not only survive processing, but also upper gut transit and arrival in the bloodstream, if whey products are to promote antioxidant levels in target organs. Studies reveal that direct cell exposure to whey samples increases intracellular antioxidants such as glutathione. However, the physiological relevance of these in vitro assays is questionable, and evidence is conflicting from dietary intervention trials, with both rats and humans, that whey products can boost cellular antioxidant biomarkers.     

Whey—pollution problem and potential utilization

The high biochemical oxygen demand (BOD₅) of whey poses a major world-wide disposal and pollution problem for the dairy industry, for which an effective and permanent solution is urgently needed. Biological waste water treatment technologies can assist in the safe disposal of whey or whey permeate within the federal environment specifications, but only at substantial cost. One alternative is use of whey, or whey permeate rich in lactose and protein, in processes in which saleable products contribute wholly or partially to the costs. Production of whey proteins by ultrafiltration, lactose hydrolysis products, and the use of whole whey or whey permeate as a fermentation feedstock are possible options. The present situation is discussed, together with projections for commercial potential, limitations of the biotechnology of whey processing, the end products and nutritional aspects.     

Functional and technological aspects of whey powder and whey protein products

Commercial whey powder, whey protein concentrates and whey protein isolates (WPIs) were evaluated for certain functional properties and for their application in full‐fat and nonfat yoghurts. The functional properties of whey products varied, and the highest functionality was recorded in samples with high protein levels. Whey powder had the lowest foaming performance and emulsifying capacity, while WPIs possessed the best functional properties of all the other samples. Curd tension (CT), viscosity and syneresis were improved in yoghurts made using fortified cow's milk or reconstituted skim milk with any whey products, while whey powder had no impact on CT.     

乳清蛋白在运动营养中的应用

乳清蛋白作为一类高质量蛋白,为运动员或健身人群快速补充蛋白质的运动产品的首选成分。本文将从乳清蛋白组成成分、乳清蛋白在运动营养方面的功效、乳清蛋白在运动营养方面的产品开发三个方面来全面介绍了乳清蛋白在运动营养中的应用。     

乳清蛋白在发酵乳制品中的应用

乳清蛋白具有良好的功能性,被广泛应用在各种食品中。本文综述了乳清蛋白产品的组成成分和功能特性,以及乳清蛋白对发酵乳制品的风味、质构、益生菌生长及功能营养的影响。指出乳清蛋白在发酵乳制品中具有良好的适应性和广阔的应用前景。