Retinyl Palmitate Isomers in Skim Milk During Light Storage as Affected by Ascorbic Acid

Effects of ascorbic acid addition on the contents of retinyl palmitate isomers in skim milk treated with or without 3 mg/mL added riboflavin were studied during storage for 30 h under fluorescent light. Light illumination induced the reduction of all-trans-retinyl palmitate and 13-cis isomer, but promoted the production of 9-cis isomer in the skim milk. Riboflavin increased the reduction of all-trans-retinyl palmitate, but decreased the formation of 9-cis isomer in lightstored skim milk. The addition of ascorbic acid greatly inhibited the light-induced reduction of all-trans-retinyl palmitate and 13-cis isomer in skim milks. Ascorbic acid also greatly increased the formation of 9-cis-retinyl palmitate in skim milks during light storage.     

反相高效液相色谱法快速测定婴儿配方乳粉中的维生素A酯类化合物

目的：开发一种快速测定婴儿配方乳粉中维生素A 酯类含量的反相高效液相色谱法。方法：直接使用二氯甲烷和甲醇体积比为2.5:1 的混合溶剂对样品进行提取,在30℃的条件下采用等度洗脱,流动相采用体积比为80:20 的甲醇- 三氯甲烷溶剂,流动相流速1.0mL/min;色谱柱温度30℃,检测波长325nm。结果：维生素A 醋酸酯和维生素A 棕榈酸酯的回收率分别为100.1% 和102.8%,多次测定结果的相对偏差分别为1.18% 和0.96%,检出限分别为3.1ng 和4.3ng。结论：本方法操作简单、精密度、回收率和灵敏度高,适用于婴幼儿配方乳粉中的维生素A 酯类的检测。     

Vitamin A: Deficiency and Food-Based Combating Strategies in Pakistan and Other Developing Countries

Vitamin A deficiency is a world wide nutritional problem especially in the developing countries that afflicts severely the health of pregnant and lactating women, infants and children. Women are the most vulnerable group affected by vitamin A deficiency during their pregnancy and lactating periods. Different strategies like food diversification, fortification, and supplementation are helpful to cope with vitamin A deficiency. Food fortification is the most cost effective, long-term approach, while supplementation is considered to be the fastidious way to uplift vitamin A status. Generally Retinyl acetate and retinyl palmitate are used in different food products as fortificants against the Vitamin A menace. In addition to these food-based strategies, educating the people regarding health and nutrition can also play an effective role.     

Vitamin A: Deficiency and Food-Based Combating Strategies in Pakistan and Other Developing Countries

Vitamin A deficiency is a world wide nutritional problem especially in the developing countries that afflicts severely the health of pregnant and lactating women, infants and children. Women are the most vulnerable group affected by vitamin A deficiency during their pregnancy and lactating periods. Different strategies like food diversification, fortification, and supplementation are helpful to cope with vitamin A deficiency. Food fortification is the most cost effective, long-term approach, while supplementation is considered to be the fastidious way to uplift vitamin A status. Generally Retinyl acetate and retinyl palmitate are used in different food products as fortificants against the Vitamin A menace. In addition to these food-based strategies, educating the people regarding health and nutrition can also play an effective role.     

Vitamin E constituents of Weaning Foods from Germinated Cereals and Legumes

Four weaning food formulations prepared from 70% 72-hr germinated rice/corn and 30% 48-hr germinated mungbean/cowpea were studied for tocopherol constituents and compared to ungerminated controls. γ-TocopheroIs were the major constituents of the mungbean-supplemented samples. The cowpea-supplemented foods contained a predominance of δ-tocopherols followed closely by γ-tocopherols, α-Tocopherols were comparatively higher in corn- than in rice-formulations. Tocopherols in the weaning foods decreased due to germination especially the γ-tocopherols of germinated corn-mungbean.     

V_A棕榈酸酯微胶囊的制备及性能研究

以聚天冬氨酸和明胶为壁材,采用单凝聚结合喷雾干燥法制备VA棕榈酸酯微囊。结果表明,最佳原料配比为:壁材浓度为0.1g/mL;芯材与壁材质量比为1∶4;壁材配比为m(明胶)∶m(聚天冬氨酸)=1∶1;乳化剂用量为1.5%;乙醇与水的体积比为1∶2。最佳微胶囊化工艺参数为:喷雾干燥进口温度为160℃,出口温度为70℃,乳化温度为38℃。经过7d的高温(60℃)加速氧化试验,微囊中VA棕榈酸酯的含量为初始含量的84.3%,较好地增加了VA棕榈酸酯的稳定性。     

Degradation of Vitamin A Palmitate in Corn Flakes During Storage

ABSTRACT: The amounts of vitamin A palmitate lost and isomers formed in corn flakes fortified with a vitamin A palmitate were determined during storage at ambient (avg. 23 °C) and elevated (45 °C) temperatures. Two vitamin A palmitate isomers, 9-cis and 13-cis, were found. The initial vitamin A palmitate consisted of 5% of 13-cis and less than 1% of 9-cis with the remaining being all-trans. In corn flakes fortified with either a complete vitamin mixture or vitamin A palmitate only, the distribution of these compounds was nearly constant throughout storage irrespective of sample type and storage conditions. The rate constant and reaction kinetics on the degradation of vitamin A palmitate were also obtained. After 6–8 wk storage, more than 90% of vitamin A palmitate was lost in all samples except corn flakes fortified with complete vitamin mixture and kept at ambient temperature. This study showed that the loss of vitamin A palmitate fortified in corn flakes was substantial even at ambient temperature. The presence of other vitamins including vitamin A, B₁, B₆, B₁₂, C, and D reduced the loss of vitamin Abut the loss was still significant.     

超高效液相色谱-串联质谱法快速测定动物源食品中万古霉素残留量

提供一种利用超高效液相色谱-串联质谱（ultra-high performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS）法快速测定动物源性食品中万古霉素残留量的方法。冻猪背膘、冻猪去骨前腿皮和 冻猪去骨前腿肉样品用0.1%甲酸水溶液-乙腈溶液（90∶10,V/V）提取,所得提取液用水饱和正己烷除脂、MCX 固相萃取柱净化,净化液经氮吹浓缩、流动相定容后用UPLC-MS/MS仪测定。结果表明：在2.0～100.0 μg/L质 量浓度范围内,万古霉素的线性关系良好,R2＞0.999 9;该方法的最低检出限为0.3 μg/kg,定量限为1.0 μg/kg; 在10.0、20.0、50.0、100.0 μg/kg 4 个添加水平下,3 种样品中万古霉素的回收率为70.05%～102.97%,相对标准偏 差≤4.65%。该方法有效解决了样品基质效应大、灵敏度低等问题,能够保证分析结果的准确性,适用于动物源性 食品,尤其是高脂肪含量的动物源性食品中万古霉素的残留量测定。     

Vitamin A stability in triple fortified extruded,artificial rice grains containing iron,zinc and vitamin A

Multi‐micronutrient‐fortified rice could be an effective and sustainable approach to combat micronutrient deficiencies. We produced hot‐extruded artificial rice grains fortified with 10 mg iron (as micronised ground ferric pyrophosphate), 5 mg zinc (as oxide, sulphate or carbonate) and 750 μg vitamin A/g [as retinyl palmitate (RP)] and measured RP stability. The rice was designed to be mixed 1:200 with natural rice. Mean RP losses were 5.3% during extrusion, 28.5% during storage and 9.8% during cooking. Storage losses after 18 weeks at 30 °C in plastic packages exposed to light were ca 40% with iron and zinc causing no further losses. In aluminium packages (no light), mean RP losses were ca 20%. Iron, but not zinc, increased RP degradation. Zinc sulphate increased the negative effect of iron. The relatively good stability of RP during hot extrusion can be explained by the closed surface and dense nature of the artificial grain protecting RP from oxidation.     

高效液相色谱法同时测定食品中18种食品添加剂

建立高效液相色谱同时测定食品中18种食品添加剂的高通量分析方法。对于不含油脂或油脂含量低的样品采用含抗坏血酸棕榈酸酯的正己烷饱和乙腈-6mol/L HCl溶液-饱和氯化钠混合溶液一次提取净化,对于油脂样品采用含抗坏血酸棕榈酸酯的正己烷饱和乙腈-乙腈饱和正己烷液液萃取。采用Ecosil C18色谱柱(250mm×4.6mm,5μm),乙腈-0.6%乙酸溶液作为流动相,梯度洗脱,用紫外检测器检测,检测波长280nm,外标法峰面积定量。18种食品添加剂在1.0～25mg/L范围内线性良好,相关系数r均大于0.99,样品在10、25mg/kg和50mg/kg三个添加水平的平均回收率为88.9%～99.9%之间,相对标准偏差为2.43%～11.7%(n=6),方法的定量限为10mg/kg。方法简便、准确,适用于食品中18种食品添加剂高通量的检测。     

应用流式细胞技术快速检测液态商品中的细菌总数

建立应用流式细胞技术(flowcytometry,FCM)快速检测液态商品牛奶、果汁中的细菌总数的方法。采用膜过滤、离心技术对果汁样品进行前处理,去除影响FCM检测的基质颗粒,使样品达到FCM可检测状态,检测限达到101CFU/mL数量级。对液态商品牛奶进行重复性和验证实验,检测结果经Q检验法和方差分析,在一定范围浓度下,FCM检测液态商品中的细菌总数与平板法成线性相关。FCM是一种比平板法检测细菌总数更加快速、准确的方法。     

Stability of Tocopherols and Retinyl Palmitate in Snack Extrudates

ABSTRACT: Fish- and peanut-containing half-products were obtained by extruding and drying tocopherol- and retinyl palmitate-fortified mixtures of tapioca starch and minced fish or partially defatted peanut flour (PDPF 60:40, wet basis). Half-products were puffed by deep-fat frying. Vitamins were determined simultaneously at each step of snack production using a direct solvent extraction method. Extrusion significantly reduced the content of tocopherols and retinyl palmitate in both products. Reduction of retinyl palmitate in fish and peanut extrudates during snack production was 48% and 27%, respectively. Final products contained more tocopherol than intermediates because of the high tocopherol content in the frying oil and its uptake.     

Nutritional Quality of Drum-processed and Extruded Composite Supplementary Foods

ABSTRACT: This study was conducted to evaluate the nutritional quality of ready‐to‐eat composite foods intended for supplementary feeding of preschool age children in Tanzania. Four supplementary foods, namely, corn‐bean‐sardine meal (CBSM), bean meal (BM), sorghum‐bean‐sardine meal (SBSM), and rice‐bean‐sardine meal (RBSM) were formulated according to the FAO/WHO/UNU guidelines. The food mixtures were extruded, drum‐processed, and cooked conventionally in the traditional way. Cooking doneness was evaluated by percent starch gelatinization and residual urease activity; biological qualities—true protein digestibility and growth performance—were evaluated using Sprague Dawley weanling rats. Efficiency in destroying phytohemagglutinins and the antinutritional factors, trypsin, chymotrypsin, and α‐amylase inhibitors, were also evaluated. Results of the study showed that starch gelatinization and residual urease activity were not significantly different (P > 0.05) between the extruded and drum‐processed diets. Relative to conventional cooking, starch gelatinization was 95% to 100% in extruded and 90% to 100% in drum‐processed products. Inactivation of urease activity ranged from 93% to 100% in extruded and 83% to 100% in drum‐processed diets. The true protein digestibilities were significantly (P≥ 0.05) higher when extruded foods, compared with drum‐processed and conventionally cooked foods, were fed to experimental animals. Animals fed extruded products gained more weight relative to those fed drum‐processed and conventionally cooked foods. Destruction of phytohemagglutinins ranged between 91% to 97% in extruded and between 90% to 95% in the conventionally cooked and drum‐processed foods. Extrusion, drum processing, and conventional cooking also resulted in significant destruction of the antinutritional factors trypsin, chymotrypsin, and a‐amylase inhibitors. These results suggest that extrusion and drum processing of cereal‐bean‐sardine composite foods result in products meeting the required nutritional quality.     

液相色谱-串联质谱法测定焙烤和油炸食品中丙烯酰胺的含量

建立了一种液相色谱-电喷雾同位素稀释串联质谱方法,并对焙烤和油炸食品中的丙烯酰胺进行定量分析。方法包括用石油醚脱脂、NaCl溶液提取、乙酸乙酯萃取和OASIS HLB固相萃取柱纯化。采用Atlantis dC18柱(5μm,150mm×2.1mm),以0.1%甲酸和甲醇(体积比90∶10)为流动相洗脱,并经过精密度、重现性和加标回收率等实验得到了验证。采用该方法测得焙烤和油炸食品中丙烯酰胺的含量分别在11.1～733.9mg/kg和136.7～5269.2mg/kg之间。该方法适用于其它类食品中丙烯酰胺的测定,由于其灵敏度高、重现性好,因此同样适合于痕量分析。     

高效液相色谱法测定食品中的单糖、双糖

本文建立了高效液相色谱法定量测定食品中的单糖、双糖,确定的色谱条件如下:WatersNH2氨基色谱柱(250mm×4.6mm),乙腈:水85:15(V/V)为流动相,流速1.0ml/min,示差折光检测器,40℃柱温,进样量10μl,外标法定量。该方法的精密度RSD<5%,回收率大于97%。在此色谱条件下20min内完成了单糖、双糖的分离,结果比较理想。研究表明此新建方法准确而快速,并能适用于多数食品中单糖、双糖的测定。     

Simplified Extraction Procedure and HPLC Determination for Total Vitamin E and β-Carotene of Reduced-Fat Mayonnaise

ABSTRACT: A simple, rapid procedure using direct solvent extraction and liquid chromatography was developed for the simultaneous determination and identification of α -tocopheryl acetate, β -carotene and tocopherols in reduced-fat mayonnaise. The method used a zero-control reference material (ZRM) (made in-house from olive oil and eggs) for accuracy determination. The vitamins and β -carotene were quantified by fluorescence and photodiode array detectors, respectively. The overall % recoveries (mean±S.D.)(n=5) for β -carotene, α -tocopheryl acetate, α -tocopherol, γ -tocopherol and δ -tocopherol were 101.4±1.4, 99.0±4.2, 102.0±3.6, 101.3±4.4 and 101.9±6.2, respectively. The method differentiates between natural and synthetic forms of vitamin E for accurate assessment of vitamin E biological activity. Comparative assays were performed using both direct solvent extraction and saponification.     

柱切换法液相色谱测定保健食品中的VA、VD、VE

建立柱切换法液相色谱测定保健食品中VA、VD、VE含量的方法.参照GB 5009.82-2016《食品中维生素A、D、E的测定》样品前处理方法,以Agilent Poroshell 120 PFP(4.6 mm×100 mm,2.7 μm)为一维色谱柱,甲醇、水为流动相梯度洗脱,分离VA和VE的4种异构体,以Agile...     

固相萃取-高效液相色谱法测定植物油中的维生素E

建立了植物油中4种维生素E的固相萃取-高效液相色谱荧光分析法.植物油中的维生素E用碱性氧化铝萃取小柱萃取和净化后用高效液相色谱法测定,在0.1～25 mg/L的浓度范围内线性关系良好,相关系数范围为0.9991～0.9996,方法检测限为0.019～0.033mg/kg;用3种植物油作添加回收率和精密度实验,回收率在8...     

超声萃取- 高效液相色谱法同时测定进出口食品中常见6 种防腐剂

使用超声萃取- 反相高效液相色谱(HPLC)技术,建立同时分离和检测食物中苯甲酸、山梨酸、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯和对羟基苯甲酸丁酯6 种防腐剂的方法。水- 甲醇(5:95,V/V)作为提取溶剂进行超声萃取,采用Supelco Discovery C18 反相色谱柱,流动相为乙腈- 乙酸铵缓冲溶液(pH4.4)进行梯度洗脱,在1ml/min 的流速和254nm 的检测波长下14min 内6 种防腐剂得到良好分离。6 种防腐剂线性范围从5μg/ml 到100μg/ml,相关系数(r)为0.9997～1.0000。方法的平均回收率为90.1%～106.3%,精密度和稳定性的RSD分别为0.58%～1.79%、0.15%～1.65%,检出限的范围为0.012～0.43μg/ml。本方法的预处理过程简便、快速,应用于30 种进出口食品中防腐剂的分析检测,检测结果灵敏、可靠。     

高压液相色谱法同时测定食品中的维生素A、D、E和K

本方法研究了应用反相高压液相色谱技术,同时测定食品中的维生素A、D、E、K。以C18柱为固定相(μ Bondapak C18,30cm×4mm),甲醇作流动相。在290nm下测定维生素A、E,在265nm下测定维生素D、K。样品的前处理分为两种,第一种皂化法,可同时测定维生素A、D、E。加标样品的回收率分别为:V_A97.2～110％,V_D92.3～102％,V_E96.6～110％。变异系数(CV％)分别为V_A2.29～3.15％,VD5.99～8.63％,V_E3.60～4.16％。第二种为酶解法,可同时测定维生素A、D、E、K四种,加标样品的回收率分别为:V_A87.62～98.01％,V_D90.23～102.7％,V_E86.18～91.09％,V_K80.15～85.07％。变异系数(CV％)分别为:V_A5.51％,V_D8.87％,V_E4.91％,V_K3.67％。