Vitamin composition of wild onion species

The data on vitamins C, B1, B2, A, E and carotenoids content in fresh-cut leaves of some species of genus of Allium cultivated in the Main Botanical garden (Moscow) are submitted. Their significance as these nutrients source is evaluated. Onion leaves usually used as flavor-odour additive (10-20 g) give only 1-4 per cent of vitamin B group and E daily recommended allowance. At the same time this quantity supply with vitamin C (20 per cent of vitamin C daily recommended allowance) and carotenoids (20-50 per cent).     

Identification of genes whose expressions are enhanced or reduced in baker's yeast during fed-batch culture process using molasses medium by DNA microarray analysis

Genes whose expression levels are enhanced or reduced during the cultivation process that uses cane molasses in baker's yeast production were identified in this study. The results showed that baker's yeast grown in molasses medium had higher fermentation ability and stress tolerance compared with baker's yeast grown in synthetic medium. Molasses apparently provided not only sugar as a carbon source but also provided functional components that enhanced or reduced expression of genes involved in fermentation ability and stress tolerance. To identify the genes whose expression is enhanced or reduced during cultivation in molasses medium, DNA microarray analysis was then used to compare the gene expression profile of cells grown in molasses with that of cells grown in synthetic medium. To simulate the commercial baker's yeast production process, cells were cultivated using a fed-batch culture system. In molasses medium, genes involved in the synthesis or uptake of vitamins (e.g., biotin, pyridoxine and thiamine) showed enhanced expression, suggesting that vitamin concentrations in molasses medium were lower than those in synthetic medium. Genes involved in formate dehydrogenase and maltose assimilation showed enhanced expression in molasses medium. In contrast, genes involved in iron utilization (e.g., siderophore, iron transporter and ferroxidase) showed enhanced expression in synthetic medium, suggesting that iron starvation occurred. The genes involved in the metabolism of amino acids also showed enhanced expression in synthetic medium. This identification of genes provides information that will help improve the baker's yeast production process.     

云南6种食用菌中维生素B1和B2的含量调查

目的 调查分析云南省6种食用菌中维生素B1和B2的含量。方法 定点采集云南省6种常见新鲜食用菌, 按GB 5009.84-2016《食品安全国家标准 食品中维生素B1的测定》和GB 5009.85-2016《食品安全国家标准 食品中维生素B2的测定》, 用高效液相色谱法测定样品中的维生素B1和B2的含量。结果 6种常见新鲜食用菌中维生素B1的含量平均值最高的是虎掌菌0.0812 mg/100 g, 最低的是干巴菌为0.0298 mg/100 g; 维生素B2含量平均值最高的是干巴菌为0.587 mg/100 g, 平均值最低的是人工种植的羊肚菌为0.0510 mg/100 g。 结论 人工种植和野生的食用菌均含有一定量的维生素B1和B2, 具有一定的营养价值。     

Effect of dietary fat on vitamin status of rats

The influence of low (1%) and high (31%) diet fat content (sunflower-seed oil and lard 1:1 at a ratio of 1:1) on vitamin A, E, B1 and B2 status of growing Wistar rats (8 rats per group) with initial body weight 80-100 g has been investigated. The semi-synthetic diet contained vitamin mixture in doses covering the physiological requirement of these animals. The increase of fat content (31%) in the diet due to the presence of vitamin E in sunflower-seed oil automatically lead to 1,7-fold increase consumption of this vitamin compared to the control group. Diet fat content did not affect the level of vitamins B1 and B2 in rat liver. Excessive intake of fat and vitamin E for 6 weeks did not influence on the content of blood plasma vitamin E and rat liver vitamin A occurs at the same time, while significant 1,9 fold elevation of liver vitamin E level and 26 per cent increase of blood plasma vitamin A concentration. The almost complete exclusion of fat from the diet had no effect on blood plasma level of alpha-tocopherol and retinol, but resulted in a significant decrease of vitamins A and E content in rat liver by 40 per cent, indicating a deterioration of sufficiency with these fat-soluble vitamins. The analysis of the results obtained in this investigation and literature data have suggested that under excessive as well as under decreased consumption of fat there is a risk of the development of polyhypovitaminosis. Vitamin complex supplementation is required to prevent a possible worsening of vitamin status under diets with modified fatty component.     

Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production

In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production.     

枯草芽孢杆菌发酵麦糟制备蛋白肽培养基研究

以麦糟为原料,对枯草芽孢杆菌（Bacillus subtilis）固态发酵麦糟制备蛋白肽培养基条件进行研究。通过单因素试验考察碳源种类、碳源添加量、料液比、磷酸二氢钾添加量和拌料水pH值对肽得率的影响,通过Box-Behnken试验方案和响应面分析优化培养基。结果表明,枯草芽孢杆菌发酵生产麦糟蛋白肽的最优培养基为：pH 7.0,葡萄糖添加量4.2%,麦糟与水的料液比1.0∶2.1（g∶mL）,磷酸二氢钾添加量0.6%,在该条件下,发酵麦糟肽得率可达12.40%。     

VITAMIN B1 AND RIBOFLAVIN IN BREWING

Vitamin B₁ has been determined in a large number of beers by the fermentation method of Schultz, Atkin and Frey which has not previously been applied to worts and beers. In general, the highest amounts were found in beers of high original gravity and in those made almost entirely from malt. Well-attenuated and unprimed beers give the highest ratio, units of B1: calories. During the brew the malt, almost the sole source of vitamin B₁, yields up the vitamin to the wort, which in its turn loses most of it to the yeast. Most of the vitamin B₁ results have been confirmed by the thiochrome method involving an entirely different principle, whilst the general validity of both methods was further confirmed by animal feedings tests. Determination of Riboflavin (vitamin B₂) by the microbiological method of Snell and Strong has led to the following conclusions:—Riboflavin is formed during germination of barley and in growing yeast. Most of the riboflavin of the malt passes into the wort during mashing and sparging and remains in the beer, the yeast not taking out any appreciable quantity. The number of microgrms. of riboflavin per 100 ml. of beer, in general, exceeds somewhat the number of degrees of original gravity.     

啤酒废酵母蛋白水解物的制取工艺

利用啤酒废酵母资源,通过破壁预处理与复合酶降解相结合的工艺,制取特定相对分子质量范围的蛋白水解物.响应面分析结果表明,在温度55～60℃,pH6.6～6.8,β-葡聚糖酶用量15～20U/g(以酵母计)的条件下,有最高的肽提取率.酶解7h,蛋白质提取率大于82%,经HPLC测定,水解产物中65%组分的相对分子质量在210～635之间,处于二肽和三肽相对分子质量范围.     

面包酵母冻干粉保护剂筛选及其生物活性分析

目的:优化真空冷冻干燥过程中保护剂配方,得到发酵性能较好的面包酵母3G-28冻干粉。方法:在对脱脂奶粉、蔗糖、吐温?80、阿拉伯胶、β-环状糊精、甘油单因素实验基础上,采用响应面实验对复合冻干保护剂的配方进行了优化,并对酵母冻干粉的发酵力、海藻糖含量、蔗糖酶活力以及发酵液中的风味物质进行了研究。结果:各因素对面包酵母冻干粉活菌数量影响顺序为:甘油浓度 > 蔗糖浓度 > 脱脂奶粉浓度 > β-环状糊精浓度;最佳复合冻干保护剂的配方为:甘油4.7%,脱脂奶粉20%,β-环状糊精15%,蔗糖5%;面包酵母冻干粉活菌数量为36.89×109 个/mL。面包酵母3G-28冻干粉的发酵能力为214 mg/h/g干酵母,海藻糖含量为44.22 mg/g干酵母,蔗糖酶活力20.27 U/g干酵母,与市售酵母菌冻干粉和初始菌株酵母冻干粉相比表现出较高的生物活性。在风味物质方面,面包酵母3G-28冻干粉与其它两者相比醇类的含量最高,表现出了良好的实用性。结论:本文探讨了面包酵母3G-28冻干粉的最佳冻干保护剂配方,得到了生物活性较优的面包酵母冻干粉,在改善面包产品品质及微生物工业化应用中具有很好的前景。     

Measurement of Glycosylated Vitamin B6 in Foods

To examine the levels of glycosylated vitamin B6 in 22 foods, each food was stirred for 2 hr at pH 6.8 and then incubated for 2 hr at pH 5.0 and 37°C with β-glucosidase (60 units per g food). Vitamin B6 content of foods was measured microbiologically before and after enzyme treatment as well as with acid hydrolysis. Animal products contained no measurable amount of glycosylated B6. Grains and legumes generally had a high level of this bound form (6–57% of the total vitamin B6). Of the fruits analyzed, orange juice had the highest level of glycosylated vitamin B6 (47%). Among fresh vegetables studied, raw carrots had the highest level (51%). For broccoli and cauliflower, the glycosylated value was higher for the processed food as compared to the raw food.     

米曲霉制备麦糟蛋白肽固态发酵培养基优化

以麦糟为原料,通过米曲霉固态发酵制备麦糟蛋白肽,研究不同培养基条件对肽转化率的影响。通过单因素实验考察碳源添加种类、碳源添加量、磷酸二氢钾添加量和料液比对肽转化率的影响,并采用响应曲面法优化培养基条件,建立肽转化率与各影响因素间的回归方程。结果表明,米曲霉发酵制备麦糟蛋白肽的最优培养基条件为:蔗糖添加量4.21%,磷酸二氢钾添加量0.51%,料液比1:3（g·mL?1）,在该条件下,发酵麦糟肽转化率可达50.73%。结果可为生物转化麦糟生产蛋白肽提供技术参考。     

啤酒废酵母泥综合利用的研究

研究了利用啤酒废酵母泥制备酵母抽提物和β-葡聚糖的相关工艺条件。结果表明,自溶-酶联法是制备啤酒酵母抽提物的理想方法,用该法制备啤酒酵母抽提物的抽提率达68.6%、蛋白质利用率达87.3%,抽提物中蛋白质、游离氨基酸态氮和复合核苷酸的含量分别达10.6%、4.2%和3.9%,远高于普通自溶工艺的技术指标;将自溶后的酵母残渣进一步制备成β-1,3-葡聚糖,通过正交试验获得了其优化的工艺条件:酵母浓度10%、碱浓度2%、反应温度80℃、反应时间4 h、碱处理次数4次。在优化的工艺条件下,β-1,3-葡聚糖得率达26.8%、成品中杂蛋白含量仅0.4%、β-葡聚糖分子质量为158ku。实现了啤酒废酵母泥的综合利用和高值化。     

面包酵母耐冷冻性能的评价方法

讨论了面包酵母耐冷冻能力的评价方法,通过对酵母在普通面团中冷冻后的相对发酵力、在液体模拟面团中冷冻后的相对发酵力和酵母细胞冷冻存活率之间的比较,发现3者之间具有显著的线性正相关性。而应用液体模拟面团测定酵母耐冷冻能力的方法简便、易控制,可用于耐冷冻酵母菌种的选育和耐冷冻酵母产品的检测中。     

Application of the SPE reversed phase HPLC/MS technique to determine vitamin B12 bio-active forms in beef

Vitamin B12 is an animal origin nutrient of a substantial importance in human diet. Its concentration in foodstuffs is low and its chemical forms are diverse, which significantly hampers its precise determination. The determination method of choice is HPLC (high performance liquid chromatography) coupled with inductively-coupled-plasma mass spectrometry (ICP-MS). The main disadvantage of this method is high instrumentation cost and complexity of handling. The aim of this work was to develop a novel approach for determination of vitamin B12 bio-active forms in beef and beef liver. The proposed method comprises the following steps: (i) vitamin B12 is cleaved off from peptides using thermal denaturation in a weakly acidic environment; (ii) sample is cleaned-up using liquid-liquid extraction and reversed phase solid phase extraction; and finally (iii) vitamin B12 is determined using HPLC and single-quadrupole mass spectrometer with ESI source. Vitamin B12 concentrations in various beef meats were in the 2.84-3.95 μg 100g(-1) range. Average B12 concentration in beef liver was 153,60 μg 100g(-1) (n = 15). Major forms of B12 present in beef meat include adenosine cobalamin (AdoCbl) and in smaller quantities hydroxycobalamin (OHCbl). Major forms of vitamin B12 present in beef liver include OHCbl (48.2%), AdoCbl (33.8%), methylocobalamin (MeCbl, 16.3%), and cyanocobalamin (CNCbl, 1.7%). Thermal treatment noticeably decreases B12 the content in meat. Depending on conditions of treatment, B12 concentrations in the 1.04-2.20 μg 100g(-1) range were found in processed meats.     

The connection between vitamin and antioxidant status of the children with decreased hemoglobin level

The investigation of vitamin sufficiency of 96 children 4-15 years old living in Moscow with decreased hemoglobin level (less 120 g/l) has been carried out in spring in 2001. Most of the children (90 per cent) had the combined deficiency of B group vitamins and carotenoids while they were sufficiently vitamin C supplied. There were only 2 per cent of children adequately supplied with all vitamins. Range correlation between hemoglobin blood level and riboflavin and tocopherols serum concentration has been observed. Marked negative linear correlation between riboflavin and malone dialdehyde serum content has been revealed: more sufficiently supplied with vitamin B2 child has lower lipid oxidative product level. Thus the necessity of vitamin B2 including in complex therapy of iron deficiency is based.     

适合老年人食用的大米筛选与复配

调查得出老年人易缺乏的营养素为钙、铁、VB1和VB2.按照国家标准对27种大米进行营养素的分析检测,筛选出了这几种营养素含量高的品种:黑龙江香米,铁含量为0.92 mg/100 g、VB.含量为0.40 mg/100 g;丝苗米3202,钙含量为18mg/100g、VB2含量为0.07 mg/100 g;黑米,钙含量为18 mg/100 g、VB2含量为0.13 mg/100 g;软黏,钙含量为20 mg/100 g、铁含量为0.77 mg/100 g;玄米3961,铁含量为0.84 mg/100 g、VB2含量为0.08 mg/100 g.根据营养膳食指南中推荐摄入值及老年人营养生理特点,从营养、口味和外观等方面科学地设计配方,复配开发出适用老年人食用的大米.     

啤酒糟酸奶的研制

以牛乳为主要原料,添加啤酒糟等成分,经过乳酸菌发酵而制成的一种富含膳食纤维的酸奶。以啤酒糟酸奶的感官品质和理化检测数据为评价指标,利用正交试验和模糊综合评价法得到最适宜的配方及工艺参数：啤酒糟添加量4%,果葡糖浆添加量10%,发酵温度42 ℃,发酵时间10 h。在此优化条件下,啤酒糟酸奶的感官评分为38.5分,酸度为84.8 °T,蛋白质含量为2.6 g/100 g、脂肪含量为2.5 g/100 g,成品风味独特,酸甜适口,是一种极具开发价值的保健酸奶。     

高效液相色谱法测定维生素片中维生素B12的不确定度评定

目的评定高效液相色谱法测定维生素片中维生素B_(12)的不确定度。方法维生素片中维生素B_(12)经纯化水超声提取,经色谱柱分离,流动相等度洗脱,使用紫外检测器550 nm检测,外标法定量来测定维生素片中维生素B_(12)的含量。依据JJF 1059.1-2012《测量不确定度评定与表示》,考察称量、标准溶液配制、样品和仪器重复测量等主要因素引入的不确定度,并对不确定度的各分量进行计算和合成。结果当维生素片中维生素B_(12)含量为0.408 mg/100 g时,在95%的置信区间下,其扩展不确定度为±0.0053 mg/100 g(k=2)。评定结果表明,实验过程中的不确定度主要来源于标准溶液配制、仪器重复测量。结论不确定度评定适用于高效液相色谱法快速测定维生素片中维生素B_(12)含量的不确定度分析,对检测结果准确度的提高具有指导意义。     

基于响应面法优化酿酒酵母培养体系

该研究以小麦胚芽为原料,2,6-二甲氧基对苯醌（2,6-DMBQ）产量为评价指标,对发酵菌种进行筛选并考察原料预处理方式的影响。在此基础上,采用单因素试验及正交试验对发酵条件进行优化。结果表明,最适发酵菌种为低糖面包酵母;最佳原料预处理方式为超声处理;低糖面包酵母发酵小麦胚芽产2,6-二甲氧基对苯醌的最优发酵条件为菌种添加量1∶8（酵母与麦胚质量比）,料液比1∶15（麦胚与水质量比）,发酵时间42 h,发酵温度28 ℃。在此最优发酵条件下,2,6-二甲氧基对苯醌的产量最高为（765.23±9.11） μg/g。