Nutrient content of milk and milk products: water soluble vitamins in baby milk formulae

A study of the content of water soluble vitamins in the 12 baby milk formulae available in the UK in April 1983 showed that levels of vitamins in the individual brands were generally in excess of those declared by the manufacturer. For cows' milk based formulae the mean excess of vitamins over the declared level was 94%. Vitamin levels in prepared formulae averaged three times the minimum recommended level. The average level of B vitamins in prepared cows' milk based formulae was six times higher than in mature human milk. For the two soya based products, the levels of vitamins were generally in excess of the declared level and levels of vitamin B12, biotin and, in one sample, vitamin B6 were considerably in excess of those found in mature human milk.     

螺旋藻乳酸菌发酵饮料的研制

通过向发酵乳中添加螺旋藻提取液,研究螺旋藻乳酸菌发酵饮料的加工工艺及配方;试制出一种色泽浅绿,风味独特、酸甜适口、细腻润滑且营养全面的新型螺旋藻乳酸菌发酵饮料。通过4因素3水平正交试验确定各种成分的最佳剂量。实验结果表明发酵乳最佳工艺条件为：接种量4％、发酵温度40℃、发酵时间3．5h;螺旋藻乳酸菌发酵饮料最佳配方为：发酵乳35％、10％螺旋藻液20％、葡萄糖8％、瓜尔豆胶0．25％。所得产品是一种富含蛋白质、维生素、乳酸菌等,集营养、保健于一体的新型螺旋藻乳酸菌发酵饮料。     

Vitamin B1 and B6 retention in milk after continuous-flow microwave and conventional heating at high temperatures

The effect of continuous-flow microwave treatment at high temperatures on the retention of vitamins B1 and B6 in raw milk with different fat content was evaluated. Results were compared with those obtained using a conventional system (tubular heat exchanger) with the same heating and cooling phases. Heat treatment of whole (3.4% fat) and skim (0.5% fat) milk at 90 degrees C produced no losses of vitamin B1 or vitamin B6 (pyridoxamine and pyridoxal). However, at 110 and 120 degrees C, while vitamin B1 content of milk remained constant, pyridoxamine increased (4 to 5% and 9 to 11%, respectively) and pyridoxal decreased (5 to 6% and 9 to 12%, respectively). Under the assayed conditions, no differences were observed between the content of these vitamins in conventionally and continuous-flow microwave-treated milk.     

Determination of water-soluble vitamins B1, B2, B6 and B12 in milk using HPLC]

Simple methods of determining the water-soluble vitamins B1, B2, B6 and B12 in milk by HPLC are described. Compared to existing procedures, the following improvements can be realized. The oxidation of vitamin B1 to thiochrome is stopped by the addition of sodium sulphite. This step significantly increases repeatability. Thiochrome is then extracted with butan-1-ol, which results in fewer co-extracts and greater selectivity. After the hydrolysis of the 5-phosphates of the vitamin B6 (pyridoxine, pyridoxal and pyridoxamine), these three vitamers are determined by isocratic HPLC as DDS-ion-pairs and with fluorimetric detection. As only microbiological methods have so far been used for the determination of minute quantities of vitamin B12 in milk, a new HPLC procedure is proposed with a detection limit of 0.2 micrograms vitamin B12/L milk.     

A systematic review and meta-analysis of the effects of pasteurization on milk vitamins, and evidence for raw milk consumption and other health-related outcomes

Pasteurization of milk ensures safety for human consumption by reducing the number of viable pathogenic bacteria. Although the public health benefits of pasteurization are well established, pro-raw milk advocate organizations continue to promote raw milk as "nature's perfect food." Advocacy groups' claims include statements that pasteurization destroys important vitamins and that raw milk consumption can prevent and treat allergies, cancer, and lactose intolerance. A systematic review and meta-analysis was completed to summarize available evidence for these selected claims. Forty studies assessing the effects of pasteurization on vitamin levels were found. Qualitatively, vitamins B12 and E decreased following pasteurization, and vitamin A increased. Random effects meta-analysis revealed no significant effect of pasteurization on vitamin B6 concentrations (standardized mean difference [SMD], -2.66; 95% confidence interval [CI], -5.40, 0.8; P = 0.06) but a decrease in concentrations of vitamins B1 (SMD, -1.77; 95% CI, -2.57, -0.96; P < 0.001), B2 (SMD, -0.41; 95% CI, -0.81, -0.01; P < 0.05), C (SMD, -2.13; 95% CI, -3.52, -0.74; P < 0.01), and folate (SMD, -11.99; 95% CI, -20.95, -3.03; P < 0.01). The effect of pasteurization on milk's nutritive value was minimal because many of these vitamins are naturally found in relatively low levels. However, milk is an important dietary source of vitamin B2, and the impact of heat treatment should be further considered. Raw milk consumption may have a protective association with allergy development (six studies), although this relationship may be potentially confounded by other farming-related factors. Raw milk consumption was not associated with cancer (two studies) or lactose intolerance (one study). Overall, these findings should be interpreted with caution given the poor quality of reported methodology in many of the included studies.     

Nutrient content of milk and milk products: vitamins of the B complex and vitamin C in retail market milk and milk products

A survey was undertaken to update and extend information on the water-soluble vitamin content of milk and milk products on retail sale. The results are discussed in relation to previously published data. Apart from vitamin C the levels of vitamins in retail pasteurized cows' milk were very similar to those found in milk from the processing dairy. Levels of total vitamin C and folic acid in UHT full cream milk were negligible; vitamin B₆ and vitamin B₁₂ were respectively 73 and 56% of the levels in pasteurized milk. Except for nicotinic acid, pantothenic acid and biotin, the levels of vitamins in sterilized milk were lower than in pasteurized milk, particularly vitamin C, folic acid and vitamin B₁₂. When compared on an equivalent dilution basis, vitamin B₆, thiamine, folic acid and, especially, vitamin B₁₂ in evaporated milk were lower than in pasteurized cows' milk. In comparison, in full cream condensed milk only vitamin B₆ was particularly low; vitamin C was particularly well preserved. With the exception of vitamin B₁₂, vitamin levels in reconstituted spray dried milk were similar to those in pasteurized cows 'milk. Levels in filled' spray dried milk were on average 70% of those in ordinary dried milks. Apart from vitamin B₁₂ the levels of B vitamins in non health food yogurt were generally higher than in pasteurized milk, especially folic acid. The levels of vitamin B₁₂ and folic acid in goats' milk were only 22 and 11 % respectively of those in cows' milk, but the nicotinic acid level was four times higher. The level of vitamin C in raw sheep's milk was about five times that in pasteurized cows' milk; other levels, apart from folic acid which was similar, were between 1.3 and 5.2 times those in cows' milk.     

Effect of dietary correction and administration of multivitamin preparations on providing rural technical school students with vitamin C and B 1

Actual nutrition and providing with vitamins C and B1 were studied in students of rural trade school (youths aged 16-17 years) in the town of Volsk, the Saratov region. The actual nutrition was corrected by inclusion of curds and other milk and vegetable products into the ration. The content of ascorbic acid in the usual and corrected rations, estimated analytically, during spring comprised 17 and 29%, and vitamin B1--49 and 75% of the recommended standard. The insufficient providing of the students with vitamins C and B1 in spring was confirmed by their low level of excretion with urine, and by lowered vitamin C concentration and activity of vitamin B1-dependent enzyme transketolase in the blood of the investigated students. The ration correction improved to a certain extent the values of providing with vitamins C and B1 but could not eliminate vitamin deficiency. Administration of "Undevitum" in a dose of 1 dragee/day during 4 months eliminated the vitamin deficiency in the ration and provided optimum vitamin levels for the students.     

紫外串联荧光检测法测定奶昔中维生素B6和烟酰胺

目的建立紫外串联荧光检测法同时快速检测奶昔中维生素B_6和烟酰胺的分析方法。方法参照GB 5009.154-2016《食品中维生素B_6的测定》和GB 5009.89-2016《食品中烟酸和烟酰胺的测定》,采用带有紫外检测器和荧光检测器的高效液相色谱仪快速检测奶昔中维生素B_6和烟酰胺。结果该方法的准确度偏差15%,线性相关系数0.99,重复性和稳定性均符合标准要求,平均回收率在95%～105%之间,均符合标准GB/T 27404-2008《实验室质量控制规范食品理化检测》中的要求,且目标峰分离效果更好,效率提升49.5%。结论该方法的检测效率和分离效果较好,符合标准要求。     

乳粉中主要B族维生素检测的GB和AOAC方法比较分析

为探究维生素B1、B2、B3（烟酸）、B6的国家标准方法和AOAC官方方法检测结果的可比性和误差来源,该研究通过对测试结果的F检验、显著性差异检验对维生素B1、B2、B3、B6的国家标准方法和AOAC官方方法进行了等效分析、并通过双向单侧t检验（TOST）对维生素B2进行了详尽的比较分析。分析结果表明,维生素B1、维生素B3和维生素B6国家标准方法和AOAC官方方法之间无显著性差异,而维生素B2国家标准方法和AOAC方法之间机理存在差异,通过等效性分析后数据结果表明两种方法等效不好;实验中发现在乳粉基质中添加酸性磷酸酶能够获得更接近可比性数据结果。     

A survey of vitamin A and D contents of fortified fluid milk in Ontario

High performance liquid chromatographic methods for measuring the concentration of vitamins A and D in fluid milk were validated and used to assess the level of these nutrients in Ontario retail milk samples. Thirteen and fifteen fortified milk samples were tested for vitamins A and D, respectively. Repeatability relative standard deviation values for vitamins A and D in milk were generally less than 10%. Recoveries varied from 87 to 107%. Vitamin D results indicated that only 20% of skim, 40% of 2% fat milk, and 20% of whole milk contained the recommended levels, whereas 46% of skim, and 77% of 2% fat milk had the required levels of vitamin A. The results indicate that vitamin level varies widely in Ontario retail milk.     

HPLC法测定保健食品B族维生素片中9种维生素B的含量

目的:建立高效液相色谱-二极管阵列检测（HPLC-DAD）法测定B族维生素片中9种维生素B成分的含量。方法:样品中的叶酸经0.3%氨溶液超声提取,样品中的生物素、维生素B₁₂和泛酸经水超声提取,样品中的维生素B₁、维生素B₂、维生素B₆、烟酸和烟酰胺经0.1%盐酸超声提取,经C₁₈柱分离,以甲醇-0.1 mol/L磷酸二氢钾溶液为流动相进行梯度洗脱,泛酸和生物素在205 nm波长处进行检测,维生素B₁、维生素B₂、烟酸和烟酰胺在256 nm波长处进行检测,维生素B₆和叶酸在287 nm波长处进行检测,维生素B₁₂在361 nm波长处进行检测。结果:9种成分能实现较好地分离,在各自线性范围内线性关系良好,决定系数R2均大于0.999,平均回收率为91.8%~106.9%,RSD为0.2%~4.8%,方法的检出限在0.05~4.7 mg/kg之间。结论:该方法操作快速简便、精密度和重复性好,能快速完成保健食品B族维生素片中9种维生素B成分的测定,并降低成本。     

毛细管电泳法对乳及乳制品中乳源蛋白的研究

采用毛细管电泳方法对原料乳、市售鲜奶、不同厂家的巴氏灭菌乳、不同厂家和产地超高温灭菌乳(UHT)、调味乳、乳酸饮料、复原乳、酸奶、奶粉中蛋白成分进行检测。选择聚乙烯醇涂层毛细管,采用柠檬酸缓冲体系,在紫外检测214nm、分离电压20kV条件下对乳及乳制品中的α一乳白蛋白(α-La)、β一乳球蛋白(β-Lg)、α-酪蛋白(α-CN)、β-酪蛋白(β-CN)和k-酪蛋白(k-CN)进行分离测定。结果表明:五种蛋白的含量在原料乳(巴氏灭菌乳、市售鲜奶)、UHT乳、酸奶、调味乳、乳酸饮料、复原乳中依次降低,而UHT乳含量随保质期的增加而减少,奶粉中蛋白质含量因其适应人群而有差异。乳及乳制品中蛋白质的含量与其存在形式、产地及加工工艺相关。     

Determination of water-soluble vitamins in soft drinks and vitamin supplements using capillary electrophoresis

A method for the determination of six water-soluble vitamins based on capillary electrophoresis (CE) operated in micellar mode was developed. Thiamine hydrochloride (vitamin B1), riboflavin (vitamin B2), pyridoxine hydrochloride (vitamin B6), pantothenic acid (vitamin B5), nicotinamide (vitamin B3), and cobalamin (Vitamin B12) could be separated in a single run. All CE parameters such as buffer composition and operation temperature were optimized in order to achieve better separation. Relative standard deviations (RSDs) of the described method ranged from 1.08 to 3.68% (intra-day precision) and 1.26 to 3.35% (inter-day precision). The method was then used for measuring various soft drinks and vitamin supplements directly without any step of sample cleanup. The determination of niacin was successful for all samples tested, reaching recoveries near 100%. Riboflavin and pyridoxine were quantified successfully in some but not all samples. Therefore, an evaluation on a case-by-case basis is mandatory. When applicable, this method provides a fast, accurate, simple, and inexpensive way to quantify selected vitamins, and is therefore well suited for routine analysis in soft drink industry.     

Stability of vitamins during the storage of liquid infant milks

The stability of the water-soluble B vitamins and the fat-soluble vitamins A and E of three liquid infant milks was followed throughout 12 months of storage at 20, 30 and 37 degrees C. Two samples were 'follow-on' milks from two different manufacturers and the other a 'junior' milk from one of these. The levels of water-soluble vitamins and vitamin E remained constant during storage at the three temperatures. In contrast, vitamin A decreased in samples from one manufacturer at all storage temperatures, and in samples from the other only at 37 degrees C. A kinetic equation was derived that made it possible to predict the influence of storage temperature on the shelf life of these kinds of products, together with the storage period during which levels of vitamin A recommended as adequate would remain.     

发酵型核桃乳饮料的研制

研究了发酵型核桃乳饮料的生产工艺。对核桃乳原浆和发酵型核桃乳饮料的理化性质进行了测定 ,并对发酵型核桃乳饮料生产工艺中的关键步骤(前配料、发酵剂、均质压力)进行了研究。     

Effect of freezing and canning on the content of selected vitamins and pigments in seeds of two grass pea (Lathyrus sativus L.) cultivars at the not fully mature stage

Seeds of the grass pea (Lathyrus sativus L.) cultivars Derek and Krab, with a dry matter content of about 33%, were used for freezing and for canning. The content of vitamins C, B1, and B2 and of carotenoids, beta-carotene, and chlorophylls was determined in raw and blanched material, in frozen products after 6-month storage before and after cooking to consumption consistency, and in canned products after 6-month storage. In comparison with the cultivar Krab, raw seeds of Derek contained 45% more vitamin C, 14% more total chlorophylls, 13% less thiamine (vitamin B1), and 7% less riboflavin (vitamin B2). The level of carotenoids was similar. Blanching of seeds led to a statistically significant decrease only in the content of vitamin C. Freezing and frozen storage significantly lowered the level of vitamin C and chlorophylls. The cooking of frozen seeds and the production of canned products and their storage resulted in a statistically verified reduction in the content of components analysed in all the samples. Greater losses were found in products prepared from seeds of the cv. Krab. After cooking, frozen seeds contained more of all the analysed components than the canned products.     

Method of simultaneous analysis of vitamins A, E and beta-carotene in dairy products

A method has been suggested for simultaneous assay of vitamins A, E and beta-carotene in milk products. A specimen sample is subjected to alkaline hydrolysis, then vitamins are extracted and separated in the column with aluminium oxide; for beta-carotene elution hexane is used, for vitamin E - acetone-hexane (10:90), for vitamin A - acetone-hexane (15:85). beta-carotene is assayed in hexane by absorption. Vitamin A and E fractions are evaporated, the residue is diluted in absolute alcohol, vitamin A is identified by absorption, vitamin E - by the colour Emmery-Engel reaction. The variation coefficient in the assay of vitamins A, E and beta-carotene was less than 10% in 5 out of 6 cases.     

以明胶为壁材制备水溶性复合维生素微胶囊工艺

以明胶为壁材,以盐酸硫胺素(VB1)、核黄素(VB2)、盐酸吡哆醇(VB6)、叶酸、烟酰胺的混合物为芯材,采用喷雾干燥工艺,制备水溶性复合维生素微胶囊。通过正交试验,考察壁材芯材比、进风温度、进料流量等工艺参数对微胶囊包埋率及产品得率的影响。结果表明：壁材芯材比对包埋率的影响最显著,进风温度对产品得率的影响比较大;较为适宜的喷雾干燥工艺条件为壁材芯材比10:1、进风温度170℃、进料流量3mL/min。在此条件下制备的水溶性复合维生素微胶囊,少数为球形,大多数表面有凹陷,平均粒径为8.93μm。     

Stabilised cocosoy beverage: physicochemical and sensory properties

Beverages formulated from extracts of blanched coconut meat and germinated soybean were compared for their proximate composition to achieve the recommendations for vegetable milks. The stability of cocosoy beverage treated with varying levels (0.2–1.0%, v/v) of a 20% gum acacia solution was determined visually and objectively after 5 days of quiescent refrigerated storage. Cocosoy beverage (50:50, v/v coconut milk to soy milk) had 3.51% protein, 3.53% fat and 5.17% carbohydrate. Similarly, it contained 13.0, 5.2, 14.7, 18.7, 0.5 and 0.3 g kg⁻¹ K, Na, Ca, Mg, Fe and P, respectively. Compared with whole coconut milk and reconstituted whole milk powder, cocosoy beverage had significantly higher total solid contents and viscosity but lower pH and buffer index. A total solids top to bottom (T/B) ratio and protein (T/B ratio) of 0.97 and 1.0, respectively, corresponding to a separation index of 1.0, was obtained in cocosoy beverage stabilised with 1.0% gum acacia. Cocosoy beverage stabilised with 1.0% (v/v) gum acacia was rated significantly higher for all the tested sensory attributes. Cocosoy beverage, similar to whole coconut milk, had high contents of glucose and sucrose, a moderate content of fructose, low content of raffinose and no trace of stachyose. Copyright © 2006 Society of Chemical Industry     

The effect of wounding intensities on vitamins and antioxidant enhancement in potato products

The effect of wounding intensity on vitamins and antioxidant activities from potato were evaluated. Potatoes were submitted to five levels of wounding intensity (A/W) including the whole peeled potato (CK), slices, pies, shreds and chopped samples. The results showed that vitamins in potato products had different responses to the same wounding intensity. Wounding intensity significantly induced VB₁, VB₂, nicotinic acid and nicotinamide accumulation in potato products, all of which were higher than that of control at each wounding intensity. Slice cutting increased the content of VB₂, VB₅, VB₇ and VB₉ compared with the control. Shreds cutting increased the content of nicotinic acid, nicotinamide and VC compared with the control. Chopped samples significantly increased the content of VB₆, chlorogenic acid and coumaric acid. The wounding intensities also induced the accumulation of L-phenylalanin ammonia lyase (PAL) activity. Superoxide dismutase (SOD) and peroxidase (POD) activities of potato products decreased after treated by cutting process.