微生物法测定婴幼儿配方乳粉中叶酸含量不确定度评估

为评估微生物法测定婴幼儿配方乳粉中叶酸含量的不确定度,结合《GB 5009.211—2014 食品安全国家标准 食品中叶酸的测定》及不确定度相关评估标准以及统计学方法,对婴幼儿配方乳粉中叶酸含量测定过程中的不确定度进行分析和评估。结果显示,婴幼儿配方乳粉中叶酸含量为（148.49±7.37） μg/100 g,k=2。其中,标准溶液和样液的配制过程是影响检测结果的主要因素,仪器测量偏差、重复性和检测方法是次要因素。表明微生物法测定婴幼儿配方乳粉中叶酸含量时不确定度较小,可用于婴幼儿配方乳粉中叶酸含量的测定。     

货架期内婴幼儿配方乳粉维生素损失率的研究

对婴幼儿配方乳粉货架期内的维生素损失进行了检测分析,研究发现,脂溶性维生素——维生素A、维生素D、维生素E、维生素K₁的损失率较高,超过了20%。另外,婴儿配方乳粉中的叶酸损失率明显高于较大婴儿配方乳粉和幼儿配方乳粉;维生素B₁、维生素B₂、维生素B₆、烟酰胺、泛酸、维生素C、生物素在货架期内较为稳定;充氮罐装和充氮盒装产品的维生素损失率相近。     

高效液相色谱法快速测定婴幼儿配方乳粉中VB2的含量

建立快速测定婴幼儿配方乳粉中VB2的高效液相色谱法.采用乙酸锌和亚铁氰化钾沉淀蛋白,C18色谱柱分离,流动相为乙酸钠(0.05 mol/L)-甲醇溶液(70∶30,V/V),荧光检测器检测.方法检出限为0.2 mg/kg,线性范围为0.01～1.0 μg/mL,加标回收率为80.4％～87.2％.该方法具有前处理简便快速,检测准确等优点,可用于婴幼儿配方乳粉中VB2的测定.     

电感耦合等离子体发射光谱法同时测定婴幼儿配方乳粉中12种元素

采用电感耦合等离子体发射光谱法同时测定婴幼儿配方乳粉中K、Ca、Na、Mg、Cu、Fe、Mn、Zn、Al、Pb、Cd、Cr 12种元素的含量,对仪器工作参数进行优化.各待测元素的标准曲线的相关系数均不低于0.9995,方法检出限为0.02～5mg/kg,样品加标回收率在87.5％～106.3％之间,检测结果的相对标准偏差小于5％.该法具有快速、准确的特点,可作为乳粉的质量控制和安全评价.     

微波消解电感耦合等离子体发射光谱仪法测定婴幼儿配方乳粉中铝的含量

建立电感耦合等离子体发射光谱法(inductively coupled plasma-optical emission spectrometry,ICP-OES)测定婴幼儿配方乳粉中铝的含量.样品经微波消解后用电感耦合等离子体发射光谱仪测定,采用外标法定量.结果表明:以称样量0.5 g、定容体积25 mL,计算方法检出限为0.5 mg/kg,铝的质量浓度与强度在0.01～50.0 μg/mL范围内呈线性关系,相关系数r=0.999 5,回收率在92.2％～107.0％之间,相对标准偏差在1.43％～2.34％之间.方法线性范围宽、检出限低、精密度好、回收率高、重现性好,能够快速准确地测定婴幼儿配方乳粉中铝含量.     

婴幼儿配方乳粉中16 种多环芳烃含量测定

采用气相色谱-质谱法,建立同时测定婴幼儿配方乳粉中16 种多环芳烃含量的分析方法,并对网购45 份婴幼儿配方乳粉中多环芳烃的污染水平进行调查研究。通过优化前处理方法,考察方法的线性关系、精密度、加标回收率及检出限等参数,采用外标法定量。结果表明：该方法中16 种多环芳烃在1～100 ng/mL范围内均线性良好（r＞0.999）,检出限为0.01～0.10 μg/kg;5、10、50 μg/kg水平下的平均加标回收率为76.2%～103.1%,相对标准偏差均小于10%;调查的45 份婴幼儿配方乳粉样品中,0～6 月龄乳粉多环芳烃检出率为86.7%,含量为0～1.12 μg/kg,6～12 月龄乳粉检出率为80.0%,含量为0～0.75 μg/kg,12～36 月龄乳粉检出率为60.0%,含量为0～0.60 μg/kg。     

B族维生素在奶牛肠道中的代谢途径

用4头装有瘤胃、十二指肠、回肠瘘管的荷斯坦泌乳奶牛为试验动物进行2个试验，估测补饲B族维生素在奶牛小肠前后的消失率。每个试验采用含Cr2O3指示剂的全混合日粮（TMR）饲喂12d，对照组不添加维生素，试验组添加维生素。试验1：奶牛补饲维生素9d，后4d为采样期，其中VB1 300、VB2 1600、烟酸12000、VB6 800、生物素20、叶酸2600和VB12 2500mg／d，在十二指肠前VB1消失率为67．8％、VB2 99．3％、烟酸98．5％、VB6 41．0％、生物素45．2％、叶酸97．0％、VB12 62．9％；试验2：给奶牛瘤胃后灌注维生素5d，后4d为采样期，维生素添加量为VB，10、VB2 2．0、烟酸600、VB6 34、生物素0．02、叶酸111和VB12 0．4mg／d，试验结果表明，除烟酸和叶酸外，瘤胃后灌注的维生素在到达十二指肠时尚未降解，说明大部分维生素在瘤胃被降解和利用。各种维生素的小肠表观吸收率差异显著，补饲维生素对小肠消失率并没有负面影响。除烟酸和叶酸外，试验组维生素小肠绝对消失量显著高于对照组，因为维生素在瘤胃内有损失，所以奶牛日粮中添加B族维生素是非常必要的。     

高效液相色谱法测定婴幼儿配方乳粉中3种醛类

建立高效液相色谱法测定婴幼儿配方乳粉中3种醛类（丙二醛、丙烯醛、4-羟基己烯醛）含量的分析方法,研究贮藏温度对婴幼儿配方乳粉中3种醛类含量的影响。考察线性关系、精密度、回收率、检出限及定量限等指标,外标法定量。结果表明：该方法在0～40μg线性良好（R2>0.999）,3种醛类检出限分别为0.3、0.4、0.3 mg/kg,定量限分别为0.8、1.0、0.8 mg/kg,平均加标回收率为88.29%～96.87%,相对标准偏差均小于10%;当乳粉贮藏环境温度高于40℃,随着温度升高,3种醛类含量均呈上升趋势,以丙二醛与丙烯醛上升显著。该研究方法具有快速、准确、重复性好等特点,能满足婴幼儿配方乳粉中3种醛类的测定。     

微生物法测定婴幼儿配方乳粉中生物素含量的不确定度评定

建立微生物法测定婴幼儿配方乳粉中生物素含量的不确定度评定方法,以进行检测结果的质量控制,提高检测数据的准确性。按照GB 5009.259—2016《食品安全国家标准食品中生物素的测定》进行婴幼儿配方乳粉中生物素含量的检测,根据JJF 1059.1—2012《测量不确定度评定与表示》和GB/T 27418—2017《测量不确定度评定和表示》等要求,对检测过程中产生的各不确定度分量进行评定,合成标准不确定度。结果表明：标准曲线拟合和重复性检测产生的不确定度最大;婴幼儿配方乳粉中3个含量生物素的不确定度报告：样品A(19.87±2.84)μg/100 g,样品B(30.35±4.41)μg/100 g,样品C(53.15±7.15)μg/100 g（置信区间95%,包含因子k=2）;随着样品中生物素含量的增高,检测结果的扩展不确定度也随之增大。     

离子色谱法与国标高效液相色谱法对婴幼儿配方乳粉中糖类的测定分析

采用高效阴离子交换分离-脉冲安培检测法建立婴幼儿配方乳粉中葡萄糖、蔗糖、乳糖、低聚半乳糖三糖、蔗果三糖、低聚半乳糖五糖、蔗果四糖及蔗果五糖的分析方法,对4 种品牌乳粉中的糖类进行定性和定量分析。结果表明：离子色谱法测定结果的相对标准偏差小于4%（n=5）,加标回收率为78.0%～96.8%,检出限为3.0～12.0 mg/100 g;采用国标中高效液相色谱法与离子色谱法进行比较,2 种方法对乳粉中蔗糖、乳糖、蔗果三糖的检出结果基本相同,但其他5 种糖高效液相色谱法均未检出,而离子色谱法均检出相应含量,离子色谱法比高效液相色谱法灵敏度高,可同时检测婴幼儿配方乳粉中多种糖类。     

The involvement of biotin in preventing the fatty liver and kidney syndrome in chicks.

Three experiments were carried out to investigate the involvement of vitamins in the fatty liver and kidney syndrome. The compounds studied, singly and in combination, were thiamin, riboflavin, nicotinic acid, pyridoxine, pantothenic acid, biotin, folic acid vitamin B12, ascorbic acid, choline and inositol and of these, only biotin prevented the syndrome. The minimum levels of supplemental dietary biotin required to prevent mortality varied from 0-05 to 0-15 mg/kg, depending on the diet. These levels were higher than the amounts required for maximum liveweight.     

The influence of folic acid, vitamins B(2) and B(6) supplementation on feed intake, body and organs weight, and liver fatty acids composition of rats subjected to 3 months moderate protein deprivation

This study was conducted to determine the effect of a 3-month dietary protein restriction - protein provided 9% of energy (20% in control group). In this dietary restriction folic acid, vitamins B(2) and B(6) were delivered in amount three times above the standard level. It was observed that animals fed a protein restricted (PR) diet weighed about 5% less than animals consuming adequate diet, but the difference was not statistically significant. Enrichment of PR diet with vitamin B or folic acid caused tendency to further suppression of weight gain, and in case of vitamin B(6) these differences were statistically significant. However, such body weight (BW) suppression was not observed when all studied vitamins were used together. Significant reductions in relative liver weight (vitamin B(2) addition), the heart (folic acid) and the lungs (vitamin B(6)) were observed. The PR diet, when all vitamins were added together, caused a decrease in weights of the lungs, heart and liver scaled to BW of rats, simultaneously with a significant increase in testis weight. Feed intake and feed conversion ratio were higher in animals given PR diet without a significant influence of vitamin supplementation (except vitamin B(6) causing further increase in feed conversion ratio). Hepatic fatty acids composition of rats was not affected by protein restriction, as well as by single vitamin supplementation. However, dietary supplementation of all examined vitamins together caused a decrease in monounsaturated fatty acids followed by an increase in polyunsaturated fatty acids participation in total fatty acids pool. It seems that enrichment of PR diet with a mixture of folic acid, vitamins B(2) and B(6) resulted in a partial reverse of growth suppression and reduction in testis size in rats.     

国内外特殊医学用途婴儿配方食品营养成分比较研究

收集国内外主要特殊医学用途婴儿配方食品营养数据,分别对国内外4 类特殊医学用途婴儿配方食品中三大产能营养素、维生素、矿物质以及在标准中要求强制添加或选择性添加的其他营养元素含量进行比较分析,并对国内外4 类特殊医学用途婴儿配方食品进行主成分分析。结果表明：氨基酸配方或乳蛋白深度水解配方中,国内品牌脂肪、VK、泛酸、牛磺酸含量显著大于国外品牌（P＜0.05）,但国内品牌叶酸含量显著低于国外品牌（P＜0.05）;乳蛋白部分水解配方中,国内品牌脂肪、锰、牛磺酸、肉碱含量显著高于国外品牌（P＜0.05）;     

Influence of folic acid, vitamin B2 and B6 supplementation on feed intake, body and organs weight, and liver fatty acids composition in rats subjected to severe protein deprivation

Growing rats fed for 3 months a low-protein (LP) diet (4.5% of energy from protein), possessed about 29% lower body weight than animals consuming adequate-protein diet (20% energy from protein). The LP diet feeding caused an increase in daily feed intake followed by a decrease in feed conversion efficiency. The enrichment of LP diet with folic acid, vitamin B2 and B6 (3 times above the level applied in the control diet) did not have any impact on rats BW and supplementation with these vitamins minimize the effect of LP diet on feed intake. The use of examined vitamins had a tendency to diminish an increase in feed conversion ratio caused by the LP nutrition. This effect was significant when all vitamins were added together. Rats fed the LP diet had higher relative weights of lungs, heart, liver and testis. Vitamins enriching the LP diet were observed to decrease a relative weight of lungs (folic acid, vitamin B6 and vitamin mixture), and liver (vitamin B6 and vitamin mixture). A tendency of increasing relative testis weight was also revealed in rats given the LP diet enriched with vitamins. The lower content of hepatic polyunsaturated fatty acids (FA) and a tendency for monounsaturated FA content to be higher were found in rats fed the LP diet. The LP diet enrichment with folic acid caused that these changes were more pronounced and statistically significant. Enrichment of LP diet with vitamins tested may cause a partial reverse of changes observed in the hepatic FA composition.     

紫花苜蓿对母猪生产性能的影响

紫花苜蓿Medicago sativa粗蛋白含量高,氨基酸平衡,粗纤维利用率高,且含有丰富的维生素、矿物质,其中的β-胡萝卜素、维生素E、维生素B2、叶酸和硒等可以降低母猪胚胎死亡率,增加窝产仔数,延长母猪的利用年限。因此,在母猪饲粮中添加适量紫花苜蓿鲜草或草粉代替部分精料,能降低饲料成本,提高母猪的生产性能。研究主要综述了紫花苜蓿粗纤维和几种重要维生素对母猪生产性能的影响。     

高产奶牛B族维生素营养的研究现状

本文阐述了B族维生素中叶酸、VBl2和胆碱的功能、代谢途径、它们的相互关系及对高产奶牛生产性能的影响。在组织代谢中，叶酸与胆碱能为奶牛体组织提供一碳基团，用于能量与蛋白质代谢、嘌呤与DNA的合成，而改善奶牛的生产性能。但叶酸提供甲基需要VBl2参与，而胆碱与蛋氨陵在提供甲基上能够互补，它们在代谢过程中相互联系和相互制约。它们的具体代谢途径、作用机制还不完全清楚。     

婴幼儿配方奶粉在不同贮藏条件下维生素D3稳定性的研究

本文跟踪研究了婴幼儿配方奶粉（简称“婴配粉”）中脂溶性维生素D₃在贮藏过程中稳定性的变化。试验方法：将3 种婴配粉经氢氧化钾乙醇溶液皂化、提取、净化、浓缩后,用正相高效液相色谱柱制备,反相C18高效液相色谱柱分离,经紫外检测器检测,外标法定量检测。试验结果：婴配粉称样量为10.0 g,定容体积为2 mL时,方法检出限为0.303 μg/100 g,方法定量限为0.909 μg/100 g。在此范围内线性回归方程Y=3.3608X+0.0388,此时R²=0.9991。结论婴配粉中维生素D₃的含量在常温和阴凉干燥环境下受到的影响较小;在低温和高温条件下随贮藏时间延长,脂溶性维生素D₃因温度分解含量减少。