不同鸡组织经次氯酸钠处理后氨基脲生成量 差异研究

目的 次氯酸钠作为一种广谱消毒剂在禽产品的消毒处理中受到广泛的应用,然而经次氯酸钠处理后的样品易导致氨基脲残留。为研究次氯酸钠处理鸡的不同组织形成氨基脲含量的差异,进行本实验探究。方法 选取鸡肉、鸡肝、鸡爪等样品,用不同浓度的次氯酸钠处理样品,经乙酸乙酯萃取净化后,结合液相色谱-串联质谱技术(LC-MS/MS)和同位素内标定量法对样品中的氨基脲进行检测,并比较不同组织样品氨基脲生成量的差异。为进一步探究其产生差异的原因,分别对不同组织样品中的蛋白质含量及氨基酸含量进行测定,比较其差异及其与氨基脲生成量之间的关联。结果 不同鸡组织样品经次氯酸钠处理后氨基脲的生成量存在着明显差异,其中鸡爪的生成量最高;进一步的蛋白质和氨基酸分析表明,氨基脲的产生和样品的蛋白质含量及氨基酸含量与组成密切相关。结论 精氨酸含量的差异是导致氨基脲生成量差异的主要原因。     

次氯酸钠消毒处理条件对鸡爪中氨基脲残留的影响

为探究不同条件下次氯酸钠消毒处理后对产生氨基脲残留的影响,以鸡爪为研究对象,考察次氯酸钠浓度、温度、浸泡时间、p H值等因素的影响。样品经次氯酸钠溶液处理后,在酸性条件下采用2-硝基苯甲醛进行衍生,调节p H值至中性后用乙酸乙酯提取,液相色谱-串联质谱仪进行测定,同位素内标法定量。结果表明,有效氯质量浓度、温度及浸泡时间与氨基脲产生量呈明显的正相关性;在p H 9~12范围内,鸡爪中氨基脲产生量随着浸泡溶液p H值的升高而增大。消毒处理过的样品经水漂洗后氨基脲含量减少50%~60%。     

次氯酸钠消毒剂对猪黄喉中氨基脲生成量的影响

目的 研究不同浸泡条件下次氯酸钠消毒剂对猪黄喉中氨基脲生成量的影响。方法 在不同有效氯质量浓度、浸泡时间、浸泡pH、浸泡温度下处理黄喉, 样品经甲醇+水(1:1, V:V)洗涤后在酸性条件下经邻硝基苯甲醛衍生, 再利用静电场轨道阱超高分辨质谱仪进行定性, 采用高效液相色谱质谱联用仪结合同位素内标法定量。结果 随着有效氯质量浓度(0.005%~0.2%)的增加, 猪黄喉中氨基脲生成量呈直线增加; 且随浸泡时间增加(24 h内)、pH增大、温度增高, 均会导致氨基脲含量增加。结论 经次氯酸钠消毒剂处理后, 猪黄喉中会产生一定量的氨基脲, 且产生的氨基脲以结合态的形式存在于猪黄喉中。     

中华鳖粉中氨基脲来源及相关性分析

研究不同处理条件下中华鳖粉中氨基脲(SEM)残留呈阳性的原因。研究从养殖环节、加工环节全链条分析氨基脲的可能来源。结果表明,养殖环节使用消毒剂与SEM呈阳性无关。高温烘干会导致氨基脲呈阳性,且随着烘干温度的升高,氨基脲检出值也随之升高。中华鳖不同部位组织的氨基脲生成量存在着明显差异,总体上鳖肉的SEM生成量高于鳖骨,但130℃高温烘干时鳖骨的SEM含量要高于鳖肉;进一步的蛋白质分析表明,氨基脲的产生和样品的蛋白质含量和组成密切相关。     

次氯酸钠消毒对水发食品中产生氨基脲的影响

为研究不同条件下次氯酸钠消毒处理对水发食品中产生氨基脲的影响，该研究系统考察了次氯酸钠溶液浓度、浸泡时间、浸泡溶液pH、浸泡温度等因素对氨基脲产生量的影响。样品经次氯酸钠溶液浸泡处理后，在酸性条件下用邻硝基苯甲醛衍生，乙酸乙酯萃取，正己烷除脂，采用液相色谱-串联质谱法进行检测。结果表明，次氯酸钠溶液质量浓度、浸泡时间、浸泡溶液pH、浸泡温度与氨基脲的产生量呈正相关性；样品经1次清水漂洗后，氨基脲产生量可显著降低。该研究可为改善水发食品生产工艺提供理论参考。     

过氧乙酸消毒液处理动物性食品后氨基脲的生成量变化

过氧乙酸作为一种高效、广谱的消毒剂在动物性食品的消毒中被广泛使用,但实验发现经过氧乙酸消毒液处理后的样品易产生氨基脲。为研究不同条件下经过氧乙酸消毒处理后食品中氨基脲生产量的差异,系统考察了过氧乙酸添加量、浸泡温度、浸泡时间、不同动物基质样品等因素对氨基脲生成量的影响。样品经过氧乙酸溶液处理后,加入过量的Na_2S_2O_3除去未反应的过氧乙酸,在酸性条件下采用2-硝基苯甲醛进行衍生,乙酸乙酯提取,液相色谱-串联质谱仪测定,同位素内标法定量。结果表明:过氧乙酸添加量、浸泡温度及浸泡时间与氨基脲的生成量呈明显的正相关性。     

60Co γ射线辐照对酱卤鸡爪杀菌效果及品质的影响

为探讨利用~(60)Co γ射线辐照酱卤鸡爪保质的最适条件,分别采用不同剂量~(60)Co γ射线对酱卤鸡爪进行辐照处理,分析辐照剂量与酱卤鸡爪菌落总数、营养成分、氨基酸和脂肪酸各组分、酸价(AC)、过氧化值(POV)、挥发性盐基氮(TVB-N)、亚硝酸盐及色度之间的关系。结果表明:~(60)Co γ射线辐照对酱卤鸡爪杀菌效果明显,样品初始菌落总数为4.3×102 CFU/g,经4.09kGy剂量辐照后即可降至10CFU/g以内;辐照对酱卤鸡爪中水分含量没有明显的影响;辐照前后蛋白质含量变化没有明显的规律;随着辐照剂量的增加,脂肪含量先升高后降低,5.74kGy以上显著高于对照样(P0.05);辐照剂量与氨基酸和脂肪酸各组分含量的变化没有明显的相关性;辐照后的样品中均有新的脂肪酸生成;辐照样的AC和POV均低于对照样(P0.05);1.88kGy时,TVB-N低于对照样(P0.05),5.74kGy以上时,高于对照样(P0.05);0.00~8.11kGy时,辐照对色度值L无明显影响(P0.05),0.00~4.09kGy时,a值无明显变化(P0.05),各试验组中b值均显著高于对照样(P0.05),5.74kGy以上时差异显著(P0.05)。     

SDS-PAGE法检测动物肌肉蛋白质加热终点温度的研究

为了探索检测动物组织蛋白质热变性程度的方法,分别对猪、牛、羊、鸡、鱼五种新鲜动物肌肉组织进行不同温度的热处理（新鲜未加热、50、60、70、80、90、100℃）,对处理后的样品提取蛋白质进行十二烷基磺酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析。结果显示,同种动物组织经不同温度热处理,所得电泳图谱具有较大差异,电泳条带的数量随温度的升高逐渐减少,猪、牛、羊三种动物肌肉组织加热到80℃后,电泳图谱不再变化,达到加热终点温度;鸡和鱼的肌肉组织加热到70℃后,电泳图谱不再变化,达到加热终点温度。不同种动物组织经相同温度热处理所得电泳图谱显示：猪、牛、羊三种动物组织蛋白质的电泳图谱相似,与鸡和鱼组织蛋白质的电泳图谱差异显著。     

7种云南野生食用菌的氨基酸组成比较分析及 营养评价

目的对产自云南本地的7种野生食用菌中的17种氨基酸进行含量测定和营养评价。方法采用酸水解法处理样品后,利用氨基酸自动分析仪测定样品中的氨基酸含量。计算7种野生菌中必需氨基酸占总氨基酸的质量分数、氨基酸比值、氨基酸比值系数和比值系数分,并根据世界卫生组织/联合国粮农组织(WHO/FAO)颁布的理想蛋白质必需氨基酸模式谱对7种野生食用菌中的氨基酸进行营养评价。结果 7种野生食用菌中氨基酸配比最为合理的是鸡枞和干巴菌,接近理想蛋白质的要求;虽然羊肚菌的各类氨基酸含量均高于其他6种野生菌,但其必需氨基酸所占比例较低;除羊肚菌外,其他6种野生菌的鲜味氨基酸含量均高于20%,其中块菌的鲜味氨基酸含量最高,达28.65%;亮氨酸和异亮氨酸在7种野生食用菌中均相对不足,并且亮氨酸是其中5种野生菌的第一限制氨基酸;甲硫氨酸在除黑鸡枞以外的其他野生菌中均相对过剩;鸡枞的氨基酸比值系数分为85.9,氨基酸营养价值最高,羊肚菌的比值系数分仅为15.15;7种野生食用菌中赖氨酸的平均含量是WHO/FAO模式谱的1.40倍。结论各类野生食用菌中的氨基酸含量差异较大,有必要对更多种类、不同产地的食用菌的氨基酸配比开展深入研究。     

15种坚果果仁氨基酸组成及含量差异分析

目的分析15种市售坚果中氨基酸组成,比较不同品种坚果间必需氨基酸、非必需氨基酸含量的差异。方法使用氨基酸分析仪对样品中氨基酸的组成及含量进行分析,用最小显著性差异法(least-significant difference,LSD)进行多重比较。结果纸皮核桃中的必需氨基酸含量最高,为6.264 g/100 g,花生中总氨基酸含量最高,为22.622 g/100 g。使用模糊辨识法对贴近度进行计算得出,FAO/WHO模式蛋白质贴近度为0.840-0.933。结论坚果中必需氨基酸和总氨基酸含量的差异显著。限制氨基酸均为蛋氨酸和胱氨酸。东北松子的FAO/WHO模式蛋白质贴近度最高,最贴近人体所需蛋白质的模式。     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the latest scientific     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Anti-mutagenic compounds from corn

In previous studies with aflatoxin-contaminated corn an uncharacteristic response for AFB₁ in the Salmonella/microsomal mutagenicity assay (Ames test) was observed and the presence of anti-aflatoxin factors in the corn was suggested. In the current study, corn was extracted and fractionated using thin layer chromatography (TLC) using different developing solvent systems and the Ames test was used to monitor for anti-mutagenic activity in the corn fractions. Both Salmonella tester strains TA98 and TA100 with metabolic activation (S9) were used. Several corn fractions, at different stages in the isolation and purification process, showed anti-mutagenic dose-responses when exposed to pure AFB₁. Corn extracts were non-toxic to the tester strains and TLC fractions that showed the best anti-mutagenic dose-responses were selected for further partial characterization analyses.