副产物对运动发酵单胞菌酒精发酵的影响

研究了乙酸、乳酸、糠醛作为酒精发酵副产物 ,对细菌酒精发酵的影响。在发酵培养基中 ,当乙酸浓度为 1 5 g/L ,糠醛浓度为 4g/L时 ,细菌酒精产量开始减少。在乳酸浓度为 0～ 2 g/L的范围内 ,没有观察到其对细菌酒精发酵的抑制作用。运用化学渗透假说 ,对酸在细菌酒精发酵中的抑制作用进行了解释 ,同时对糠醛在细菌酒精发酵中的抑制作用进行了理论探讨     

发酵木糖产乙醇菌种筛选及应用

采用传统的菌种筛选方法,对样品进行了发酵木糖生产酒精的酵母菌的筛选,得到一株能够发酵木糖生产酒精的酵母菌,经初步鉴定为假丝酵母菌.其在木糖含量2%、30℃、100r/min的条件下发酵,酒精产量达到3.10g/L,基本达到了一般野生酵母的水平.再利用其发酵麦糟水解液,乙醇产量最高为4.24g/L.结果表明,Y-4T-1具有抵抗麦糟水解液中的乙酸、糠醛、羟甲基糠醛等抑制物生长的能力,为发酵麦糟生产酒精的进一步研究提供了菌种支持,为生物质燃料生产燃料乙醇的研究提供了新的思路.     

几株酒精酵母的发酵性能比较

酵母菌种的好坏直接影响产品质量、设备利用率和产品产量，从而影响企业的经济效益。对1308菌株、1300菌株、安琪超酒酵母、奥特奇酵母产酒精的发酵、耐乙酸、耐乳酸、耐受酒精能力、耐受温度、耐渗透压、耐pH进行了发酵实验比较。结果表明，1308菌株、1300菌株、安琪超酒酵母、奥特奇酵母各有优缺点；菌株1308及安琪超酒酵母生产性能良好。     

UVB照射对酵母菌生长及酒精发酵的影响

探讨了UNB照射对酵母菌生长和酒精发酵的影响。试验结果表明，UVB照射培养对酵母茵的生长有一定影响．细胞形态也会发生一定的变化：经UVB照射的酵母菌，其凝集力略有增加，但酒精发酵能力基本保持不变、另外，从UVB照射培养36h的菌液中分离得到一株原料出酒率为36．39％，比对照提高0．86％的酒精发酵酵母菌。     

机械化生产黄酒酵母菌性能的研究

针对“三边发酵“理论中黄酒酵母菌性能的要求,通过研究黄酒酵母在TTC培养基中的变色情况、发酵力情况、糖化酶糖液中酵母生长情况、酵母耐酒精度、酵母形态和产香、酵母醭生成情况、酵母起发速度、酵母巨大菌落形态、酵母死灭温度、酵母与杆菌在MRS液体培养基中共同生长和凝聚情况及在锥形瓶中发酵试验.从中筛选出2#和3#酵母菌株搭配使用,更加适宜于机械化黄酒中的大罐发酵.     

枇杷醋生产中酒精发酵工艺优化及酸味特征分析

采用金华1号红肉枇杷为试验材料,对枇杷醋生产工艺中酒精发酵工艺参数进行优化,并分析醋基的酸味特征。研究酵母种类及接种量、发酵pH、发酵温度和初始糖度对枇杷醋醋基品质的影响,并以酒精度为响应值确定最优的发酵条件。结果表明,酵母菌种Yb为枇杷醋醋基酒精发酵优势酵母菌种,最优工艺参数为发酵温度25℃,酵母接种量0.05%、pH 3.5,该条件下枇杷醋醋基酒精度8.50%Vol,有机酸含量12.228g/L。枇杷醋醋基酸味特征主要由苹果酸、乳酸、乙酸和琥珀酸构成,占总有机酸的95.4%,构成枇杷醋醋基酸味感的94.7%。高含量酒精和适当含量的有机酸是后续醋酸发酵后醋酸含量的保证以及构成枇杷醋果酸味和一定功能作用的重要成分。     

不同干酵母对甘蔗汁酿酒特性的影响

为研究不同酵母对甘蔗果酒的发酵影响,以新鲜的甘蔗压榨汁为原料,常温下选用葡萄酒高活性干酵母、耐高温高活性干酵母和发利干酵母三种商业活性干酵母进行液态发酵酿制甘蔗果酒。研究探讨了三种酵母菌的生长曲线、凝聚性、发酵度、发酵力、酸化力和产酒精能力等酿酒发酵特性。结果表明,三种酵母菌作用甘蔗汁的发酵过程中,酵母菌生长曲线趋势基本一致,三种酵母菌的凝聚值F<20%,均为非凝聚性酵母。三种酵母菌的发酵力基本相当的,最终产酒精的能力差距不大,其中葡萄酒高活性干酵母最终产酒精为12.2% vol,耐高温高活性干酵母和发利干酵母均为12.0% vol。从三种商用酵母菌对甘蔗汁酿酒的各发酵特性来看,葡萄酒高活性干酵母略优于耐高温高活性干酵母和发利干酵母。研究结果为甘蔗汁发酵酿制风味甘蔗果酒提供了技术参考。     

酒精沼气双发酵偶联工艺中沼液有机酸对酒精发酵的影响

木薯酒精蒸馏废液经厌氧沼气发酵后的沼液全部回用作为酒精发酵配料的工艺用水,形成酒精沼气双发酵偶联工艺。研究发现,乙酸和丙酸是抑制酒精发酵的主要的小分子有机酸。乙酸对酒精发酵产生抑制的有效质量浓度为0.4g/dL,丙酸对酒精发酵产生抑制的有效质量浓度为0.1g/dL,乳酸质量浓度达到2.5g/dL时才会对酒精发酵产生影响。     

耐高温酒精酵母菌株的筛选及发酵能力比较

采用酵母菌富集培养方法和选择性培养基从中国传统大曲酒等基质中共分离得到58株具有一定的酒精发酵能力的酵母菌株。经过初筛和复筛,从中筛选获得1株能在33℃～42℃生长良好,并具有良好酒精发酵性能的酵母菌株XG-1,经分类鉴定为酿酒酵母菌（Saccharomyces cerevisiae）。40℃液体摇瓶培养条件下,XG-1菌株活菌数占总菌数的比率较安琪耐高温酿酒高活性干酵母（TRADY）高15％。将其与TRADY菌株进行木薯酒精发酵比较,33R2条件下两者的酒精发酵能力相当,但在42℃时进行酒精发酵,XG-1菌株的酒精度比TRADY菌株高20％。     

泰和乌鸡酶解液对酒精发酵的促进作用研究

将0.5‰泰和乌鸡酶解液加入酒精发酵培养基中,以加入5‰的尿素样作对照,观察其对酒精发酵的影响。结果表明,加入泰和乌鸡酶解液可促进酵母繁殖;提高酵母菌耐酒精能力,保护酵母菌的活力;提高酒精发酵液中残糖利用率,使发酵更彻底,提高出酒率;缩短酒精发酵时间,从而提高设备利用率。     

Physicochemical Properties of Dietary Fibres Prepared from Ambarella (Spondias cytherea) and Mango (Mangifera indica) Peels

The preparation of fibres from mango and ambarella peels can offer a way to upgrade by-products. Comparatively to lime, ambarella and mango fibres were prepared from their corresponding peels using ethanolic treatment (85% at 70 °C/5 min). The peels were characterised for their dry matter content, pH and apparent viscosity. The soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) contents of the samples were determined. Hydration capacity of these fibres was evaluated. Results showed that the ethanolic treatment of the peels (85% at 70 °C/5 min) had significant (p?<?0.05) effects on the contents of neutral sugars and uronic acid (from 105 to even 203 mg/g in case of mango fibre). For ambarella fibres, the proportion of IDF (51%) was highest and that of SDF (34%) was lowest. Mango and lime fibres exhibited similar values of IDF (40–43%) and SDF (50–57%). Mango peel fibres had higher hydration capacities than ambarella and lime fibres. The best dietary fibres content and the high hydration capacities of mango peel fibres favour their exploitation in dietary fibre-rich foods preparation.     

Quantification of gallic acid and ellagic acid from longan (Dimocarpus longan Lour.) seed and mango (Mangifera indica L.) kernel and their effects on antioxidant activity

Gallic acid (GA) and ellagic acid (EA) have been identified in longan seed and mango kernel by the use of reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with photodiode array detection (DAD). The ethanolic extract of longan seed contained 23.3 and 156 mg/100 seeds of GA and EA, respectively. The ethanolic extracts of mango kernel contained approximately 87% more GA than the longan seed ethanolic extracts but about 32% less EA. After heat treatment and acid hydrolysis, mango kernel had higher concentrations of GA and EA, contributing to more potent antioxidant activity. The results demonstrated rich sources of GA and EA in longan seed and mango kernel which might provide a novel source of these natural antioxidants.     

Utilisation Potential of Feijoa Fruit Wastes as Ingredients for Functional Foods

Feijoa fruits have high antioxidant activity as they contain significant concentrations of polyphenols (PPs), carotenoids and vitamins. This study evaluates the colour, pH, total soluble solids (TSS), pectin fibre content, total extractable PP content (TEPC) and total antioxidant activity of the extracts generated from the fruit wastes (primarily skin and some flesh) remaining after feijoa flesh consumption. Extractions were conducted at room temperature and 50 °C using accelerated solvent extraction technology and different extraction media [water, acidified water (containing citric acid, pH?3.5), and 30, 50 and 80 % (v/v) aqueous ethanol solutions]. Results show that the composition and properties of the extracts depend on the extraction media and, to a lesser extent, on the extraction temperature. The 80 % ethanolic extract was bright green in colour. The water and acidified water extracts showed more browning than the ethanolic extracts, suggesting possible detrimental sensory impacts for food applications. The TSS decreased in the order of 80, 50 and 30 % ethanolic and water extracts. The 50 % ethanolic extract had the highest TEPC and antioxidant activity at both extraction temperatures, which was supported by high performance liquid chromatography analyses. The extracts produced with solutions containing less ethanol, especially water extracts, had higher pectin contents. The UA content of the extract produced using water alone was the highest (5.56 % as GalA) at 20 °C, whilst that produced using 30 % ethanol solution was the highest (3.90 % as GalA) at 50 °C. Higher extraction temperature (50 °C) resulted in lower pectin contents. These results demonstrate the potential of feijoa waste extracts, especially 50 and 80 % ethanolic extracts, as ingredients for functional food applications.     

柠檬醛对副溶血性弧菌的抑制作用

有效预防和控制副溶血性弧菌对食品的污染对于保障公众健康具有重要意义。本研究首先利用琼脂稀释法测定7?种植物源活性物质（丁香酸、阿魏酸、绿原酸、硫辛酸、原儿茶酸、原儿茶醛和柠檬醛）对副溶血性弧菌的最小抑菌浓度,在此基础上选择柠檬醛进行后续实验;通过检测经柠檬醛处理后的副溶血性弧菌生长曲线、细胞膜电位、胞内ATP浓度、细胞膜完整性以及细胞形态的变化,探究柠檬醛对副溶血性弧菌的抑制作用及可能的作用机理。结果表明：柠檬醛相比于其他6?种植物源活性物质对副溶血性弧菌有更好的抑菌效果,其对两株标准菌株和8?株分离菌株的最小抑菌浓度在0.10～0.60?mg/mL范围内;柠檬醛能够引起副溶血性弧菌细胞膜电位去极化、胞内ATP浓度降低及细胞膜完整性下降,同时可使细胞皱缩变形。本研究结果表明柠檬醛具有良好的抑菌功效,并有潜力作为天然的抗菌物质应用于食品工业。     

Fish spoilage bacterial growth and their biogenic amine accumulation: Inhibitory effects of olive by-products

The antimicrobial effects of olive by-products (olive leaf extract, olive cake, and black water) on foodborne pathogens and fish spoilage bacteria isolated from anchovy, mackerel, and sardine were investigated. Total polyphenol contents in olive by-products were determined by the Folin–Ciocalteu procedure and their chemical composition was also evaluated by gas chromatography-mass spectrometry. The minimum inhibitory concentrations of olive by-product were performed using the broth microdilution method. Their impact on bacterial growth and biogenic amine production were also monitored in anchovy infusion decarboxylase broth. The total phenol content of olive cake and black water were 14.9 and 20.9 mg gallic acid/g extract, respectively. The major compounds were ethyl oleate (52.3%) and squalene (22.8%) in olive cake and palmitic acid (12.2%), phenanthrene (11.9%), and linoleic acid (11.4%) in olive leaf, while black water consisted of 51.1% squalene and 17.5% oleic acid ethyl ester. The minimum inhibitory concentration of olive leaf ranged from 0.78 to 25 mg/mL. Bacterial strains were more sensitive to olive leaf than other olive by-products. Bacterial load in anchovy infusion decarboxylase broth did not always correlate well with biogenic amine production. The effect of olive leaf, olive cake, and black water on biogenic amine accumulation varied depending on specific bacterial strains and biogenic amine. Olive cake and olive leaf generally had a stronger effect on reducing histamine accumulation by bacteria. Therefore, the results showed the potential effect of olive by-products in preventing or reducing the accumulation of histamine, which may beneficially affect human health.     

Suillus collinitus methanolic extract increases p53 expression and causes cell cycle arrest and apoptosis in a breast cancer cell line

In the present work, methanolic, ethanolic and boiled water extracts of Suillus collinitus were chemically characterised and submitted to an evaluation of their bioactive properties (antioxidant potential and cytotoxic activity in tumor cell lines). Phenolic acids and sugars were identified chromatographically and quantified in the methanolic and boiled water extracts, respectively. S. collinitus ethanolic extract had the highest antioxidant activity. Nevertheless, with respect to cell growth inhibition, the methanolic extract was the most potent extract, particularly in MCF-7 cells (GI(50) 25.2±0.2μg/ml). Moreover, the GI(50) concentration of this extract induced a G1 cell cycle arrest, with a concomitant decrease in the percentage of cells in the S phase. Furthermore, it caused an increase in the percentage of apoptotic cells, from 6.0±0.2% in untreated cells, to 15.3±2.0% in cells treated with the GI(50) concentration and to 16.3±2.0% in cells treated with 2×GI(50) concentration. In addition, 48h treatment with the GI(50) concentration caused a strong increase in the levels of p53, p21, and cleaved PARP, together with a decrease in Bcl-2 and XIAP. Results indicate that S. collinitus may be a promising source of bioactive compounds. Particularly, its methanolic extract appears to have a p53-mediated effect on the normal cell cycle distribution and apoptosis induction in a human breast tumor cell line.     

槟榔加工副产物代料栽培对平菇子实体及物质转化的影响

目的:本文旨在探讨以槟榔加工副产物为替代料栽培平菇,对平菇生长、子实体营养成分及物质转化的影响。方法:以平菇一号为供试菌种,以菌丝体长速、长势为指标研究了槟榔副产物培养料水分含量、粒径大小和替代料比例对菌丝体生长阶段的影响。研究了不同水分含量、粒径大小以及替代料含量代料栽培对平菇子实体发育的影响,以及槟榔加工副产物在平菇栽培过程中的多酚、黄酮、纤维素、半纤维素的物质转化规律。结果:以槟榔加工副产物为替代料栽培平菇时,平菇在不同配方培养料上均可正常生长。其中以槟榔核、槟榔蒂作为替代料,培养基质中最适水分含量分别为65%和70%,最适粒径大小为0.15~0.3 cm;出菇试验中,不同比例代料栽培的四种平菇子实体中,槟榔核50%替代组多酚、黄酮含量均为最高,分别达到51.05 mg/g和0.42 mg/g,与对照组相比提升了53.21%和133%。槟榔核30%替代组多糖含量最高,为42.01%,与对照组相比提升了77.10%。栽培后,槟榔蒂50%替代组培养料中黄酮含量下降幅度最大,为86.70%;槟榔核50%替代组多酚含量下降幅度最大,为46.99%。结论:本研究为槟榔加工副产物代料栽培平菇提供了理论依据,也为槟榔副产物的综合利用提供了新途径。     

玉米皮渣类纤维兼氧发酵产丁二酸

采用酶酸两步法水解玉米皮渣,重点考察了稀HCl水解条件变化对还原糖产率的影响,并以产琥珀酸放线杆菌为发酵菌株,探讨以玉米皮渣类纤维为原料替代葡萄糖为碳源,兼氧发酵产丁二酸的可行性。结果表明:在HCl浓度1.5%,底物浓度为12%,100℃水解4h的水解工艺下,还原糖产率达83%。在还原糖质量浓度40g/L,玉米浆为氮源,35℃发酵60h的条件下,丁二酸产率达到19.41g/L。应用玉米加工副产物玉米皮渣和玉米浆为原料发酵产丁二酸具有良好的应用前景。     

ORGANIC ACID METABOLISM OF YEASTS DURING FERMENTATION OF ALCOHOLIC BEVERAGES—A REVIEW

The acids of alcoholic beverages are largely those present in the raw materials but the concentrations of some may be changed by yeast action during fermentation. In addition a number of other acids are formed by the yeasts often as by-products of main metabolic pathways. The inter-relationships of organic acid and amino-acid metabolism, yeast growth and formation of fusel alcohols are discussed.     

Phytochemicals of ethanolic extract and essential oil of Persicaria hydropiper and their potential as antibacterial agents for food packaging polylactic acid film

This study aims to determine phytochemicals and antibacterial activity of ethanolic extract and essential oil of Persicaria hydropiper, and their potential as antibacterial agents in polylactic acid (PLA) film. The yield of ethanolic extract and essential oil were 11.02 and 0.70%, respectively. Chlorogenic acid, ferulic acid, rutin, myricetin and quercetin were detected as major components in the P. hydropiper ethanolic extract, while dodecanal, caryophyllene, caryophyllene oxide, decanal, α‐caryophyllene, citronellol, heptadecanal, linalool and phytol were detected in the P. hydropiper essential oil. Based on the disc diffusion assay, both ethanolic extract and essential oil of P. hydropiper possessed antibacterial activity against bacteria Staphylococcus aureus only at different concentrations, with minimum inhibitory concentration values: 0.625 and 5 mg/ml, respectively; and minimum bactericidal concentration values: 5 and 40 mg/ml, respectively. However, they found to show antibacterial activity against three bacteria S. aureus, Escherichia coli and Salmonella Typhimurium at different concentrations and time using time‐kill kinetics assay. Incorporation of ethanolic extract and essential oil in PLA film also exhibited an antibacterial effect against S. aureus. Our findings confirmed the potential use of both P. hydropiper ethanolic extract and essential oil as antibacterial agents in biodegradable PLA film.