The effect of nitrogen source on yeast metabolism and H2S formation

The impacts of aspartic acid and glutamine used as nitrogen supplements for alcoholic fermentations conducted by Saccharomyces were studied. Synthetic grape juice media and commercially prepared grape juices were supplemented with diammonium phosphate, aspartic acid, or glutamine to increase yeast-assimilable nitrogen concentrations to 250 mg N/L prior to fermentation. Two yeast strains, UCD522 and EC1118, were inoculated at 10⁵ CFU/mL and fermentations were monitored for soluble solids, hydrogen sulfide (H₂S), and residual amino acids. In general, unsupplemented media/juices fermented slower than supplemented ones, produced more H₂S, and contained lower concentrations of amino acids after fermentation. Among the supplemented treatments, fermentation rates, H₂S production, and amino acid utilization varied depending on the nitrogen source and yeast strain. Those fermentations supplemented with aspartic acid were generally slower and sometimes did not achieve dryness. In contrast, glutamine additions yielded fermentation rates and H₂S production equivalent or better than other supplemented treatments. Based on these results, the use of glutamine appears promising as an alternative nitrogen supplement for wine production.     

Chemical and microbiological quality of sugar cane juice influences the concentration of ethyl carbamate and volatile congeners in cachaça

The aim of this study was to assess the influence of heat treatment of sugar cane juice, supplementation with urea and double distillation on the concentration of volatile congeners (acetic aldehyde, ethyl acetate, n‐propyl, isobutyl and isoamyl alcohols and acetic acid) and contaminants (methanol, 1‐propyl and 2‐butyl alcohols, copper, and ethyl carbamate) in cachaça. Samples of fresh sugar cane juice, sugar cane juice submitted to heat treatment and contaminated sugar cane juice were supplemented (or not) with urea and fermented. The washes so obtained underwent single and double distillation. Supplementation with urea stimulated ethyl carbamate formation. The distilled products that originated from contaminated worts presented higher concentration of acetic acid and ethyl carbamate. Double distillation reduced the concentration of contaminants. The best quality pot still cachaça was obtained employing heat treatment of sugar cane juice, nonsupplementation with urea and double distillation. Copyright © 2015 The Institute of Brewing & Distilling     

三种杂粮及其复合低温火腿肠营养成分分析及评价

分别检测了燕麦、苦荞麦、小米3种杂粮原料,以及所对应的杂粮复合低温火腿肠的营养成分,并对其进行了营养价值评价。结果表明:燕麦片、苦荞麦粉、小米3种杂粮原料的脂肪含量都较低,均在10%以下。燕麦片的蛋白质含量最高,达到13.4%,且所含钙、铁、锌均较高,分别为683、48.1、25.3mg/kg。苦荞麦粉硒元素的含量最高,达到0.12mg/kg。对杂粮原料进行了氨基酸营养评价,小米的E/N值为55.03%,最接近FAO/WHO标准模式。杂粮复合低温火腿肠中,蛋白质含量均高于GB/T 20712—2006《火腿肠》国家标准指标,淀粉含量均在10%以下。小米复合低温火腿肠中VB1、VB2含量相对较高,分别达到156.6μg/100g和12.8μg/100g。其他的功能性营养成分检测结果表明:苦荞麦复合低温火腿肠中特有的生物活性物质黄酮含量达到了2mg/kg,膳食纤维含量最高,达到了3.4%。对杂粮低温复合火腿肠进行了INQ值评价,3种复合低温火腿肠的钙、铁、锌、VB1的INQ值均高于1,其中小米复合低温火腿肠的INQ值总体最高。杂粮复合低温火腿肠理化及卫生指标结果表明,3种低温火腿肠的理化及卫生指标均符合GB/T 20712—2006《火腿肠》的相关规定,表明产品卫生安全指标合格。     

Nutrient Composition of Chlorella spp. and Monodus subterraneus Cultured in a Bubble Column Bioreactor

The nutritional composition of two marine microalgae, Chlorella spp. and Monodus subterraneus, cultured in an outdoor bubble column photobioreactor used in batch mode was analyzed. Nutrients are reported at different microalgal growth phases. The proximate composition (moisture, crude protein, available carbohydrates and saponifiable oil), fatty acid and carotenoids at different growth stages were determined. On average, the biomass contained high amounts of protein in the two analyzed microalgae for all growth stages. Chlorella spp. biomass contained α-linolenic acid as predominant fatty acid, while M. subterraneus biomass was rich in palmitic and eicosapentaenoic fatty acids, which reached a maximum EPA productivity at the exponential growth phase (65.0 mg· L^?1·day^?1). For both microalgae, carotenoid content was strongly influenced by the growth phase. Chlorella spp. biomass was found to be good sources of lutein and β-carotene, while M. subterraneus biomass exhibited high amounts of neoxanthin and β-carotene. A high carotenoid productivity was obtained for this microalgae at the stationary growth phase, with 19.4 mg·L^?1·day^?1. The results of this study clearly demonstrated the relevance of microalgae for potential use in functional foods, justifying their commercial production.     

烧鸡加工过程中营养成分变化研究

研究了传统工艺和腌制工艺加工的烧鸡煮制过程中水分、蛋白质、脂肪和氯化钠含量的变化,结果表明,不同处理加工的烧鸡煮制过程中水分含量呈下降趋势,蛋白质和氯化钠含量随煮制时间的延长而升高,脂肪含量煮制1h时最高,其后随煮制时间的延长而下降;烧鸡经腌制处理可提高成品率,降低盐分含量,但对煮制过程中蛋白质和脂肪含量影响不大。     

Healthy Snacks: Using Nutrient Profiling to Evaluate the Nutrient‐Density of Common Snacks in the United States

Objective: To quantify and compare the nutrient‐density of commonly consumed snacks using two nutrient‐density measures, Nutrient Rich Foods Indices 9.3 (NRF 9.3) and 15.3 (NRF 15.3). Design: Identify commonly consumed categories of snacks and individual snack foods, calculate NRF 9.3 and 15.3 scores, rank snacks by category and by individual food based on nutrient density, compare and contrast scores generated by the two NRF Indices. Main Outcome Measures: NRF 9.3 and 15.3 scores. Analysis: Averages and standard deviations of nutrient‐density scores for each snack category. Results: Vegetables and coffee/tea received the highest category scores on both indices. Cakes/cookies/pastries and sweets had the lowest category scores. NRF 9.3 scores for individual snacks ranged from –46 (soda) to 524 (coffee). NRF 15.3 scores ranged from –45 (soda) to 736 (coffee). Conclusions and Implications: If added to food labels, NRF scores could help consumers identify more nutritious choices. The differences between NRF 9.3 and 15.3 scores generated for the same foods and the limitations of these indices highlight the need for careful consideration of which nutrient‐density measure to include on food labels as well as consumer education.     

白皮黄瓜果实农艺性状与主要营养成分相关性分析研究

对白皮黄瓜果实农艺性状与主要营养成分进行观测分析与相关性分析,研究结果表明:白皮黄瓜营养丰富,VC和可溶性固形物含量相对较高,瓜条短粗,刺溜相对稀疏。营养成分及果实农艺性状各品种间存在极显著差异。各营养成分含量随果实农艺性状表现呈现规律性变化,存在一定的相关性。板桥白黄瓜氨基酸总量最高,为0.25%;香玉龙黄瓜VC含量最高,为6.42mg/100g;翠玉8号可溶性固形物含量最高,为3.1%。     

发芽大豆的营养价值及其复合乳生产技术

研究了大豆籽粒在发芽过程中营养成分变化和用发芽大豆为原料生产豆乳与牛乳复合的工艺。大豆在发芽过程中 ,随着胚根长度的增加 ,可溶性蛋白质呈先升后降的趋势 ,游离氨基酸始终在增加 ,脂肪和植酸则持续下降。大豆胚根长度 2mm时 ,可溶性蛋白质增加量和植酸减少量分别为浸泡结束时的 5 6 88%和 45 99% ;胚根长度 15mm时 ,游离氨基酸比浸泡结束时增加 1 0 3倍。发芽大豆用质量分数 0 2 %的NaHCO3 溶液 80℃下处理 2min ,经清洗、去皮、热磨、滤浆和煮沸等处理 ,发芽豆乳的豆腥味轻微 ;豆乳与牛乳以体积比 4∶6的比例制成的复合乳营养合理 ,风味协调     

不同品种鲜蛋品质差异分析

目的探究褐壳蛋、粉壳蛋和白壳蛋3种类型鸡蛋的品质差异以及对于蛋粉加工的潜在影响。方法选用京红1号、京粉1号和京白1号所产的褐壳蛋、粉壳蛋和白壳蛋作为试验对象,对37周龄和51周龄蛋鸡所产3种类型鸡蛋的蛋品质进行分析比较。结果 37周龄和51周龄的白壳蛋蛋壳厚度、蛋壳比例和蛋壳强度均显著低于其他2个类型鸡蛋(P0.05);37周龄时3种类型鸡蛋的蛋黄水分含量没有显著性差异(P0.05);白壳蛋蛋清水分含量以及总水分含量均较其他2个类型鸡蛋要低。37周龄时褐壳蛋的蛋黄蛋白质和脂肪含量均显著高于其他2个品种,白壳蛋次之,粉壳蛋最低。37周龄时白壳蛋的蛋清蛋白质含量显著低于其他2个品种。由于蛋清中脂肪含量极少,本试验不予考虑。结论褐壳蛋加工成蛋粉后具有更好的营养价值,而白壳蛋可以提高蛋粉加工的产量。     

甜高粱秸秆主要营养成分含量及分布研究

通过对甜高粱秸秆主要营养成分含量及分布的研究,为提高甜高粱秸秆的能量密度和饲料质量提供依据。对甜高粱组织进行人工分离、分别测定其营养成分,结果发现糖分主要存在于髓,其次是皮中,占总量的91%以上;蛋白质、脂肪、灰分主要存在于叶中;纤维素主要存在于皮中;穗中的各营养素含量很高,但总量很少。营养素在秸秆,组织中的不均衡分布为秸秆的分离利用提供了条件。