混菌发酵生产啤酒醋工艺的研究

通过实验确定了以醋酸菌AS1．41和产香酵母XJB45为实验菌种发酵生产啤酒醋的最佳工艺。实验结果表明,啤酒醋的最佳生产工艺为：菌种混合比例4：2,接种量15％,酒精含量5．5％,发酵温度30℃,转速180r／min。     

生物发酵法制丁二酸生产工艺的研究与应用

丁二酸是一种重要的化工原料,广泛用于食品、医药和化工等行业,市场前景广阔。微生物发酵法生产丁二酸具有高效、环保、可持续利用的特点,是一种新型的绿色化工生产工艺。本文介绍了微生物发酵法制备丁二酸的生产工艺并对其应用前景进行了展望。     

Exopolysaccharides production as affected by lactic acid bacteria and fermentation time

The aim of this work was to examine the ropiness of Lactobacillus helveticus BCRC14030, L. helveticus BCRC14076, and Streptococcus thermophilus BCRC14085, and evaluate the effect of fermentation time on exopolysaccharides (EPS) production by the ropy strain. Each of the three strains was inoculated in skim milk medium and incubated in a fermenter for 0–84 h at pH 5, 37 °C. The fermented samples, containing a net volume of 300 ml skim milk, were withdrawn at intervals of 0, 12, 16, 24, 32, 36, 48, 60, 72, and 84 h for determinations of ropy condition, EPS yield, and molecular mass. EPS with ropiness values of 11.3–21.0 mm, produced from L. helveticus BCRC14030 at 32–60 h demonstrated the ropy nature of the strain. Those EPS were composed of high molecular mass of 26,500 kDa. The highest EPS yield of 0.73 g l⁻¹ from this strain was observed (P < 0.05) at less favourable fermentation condition of 60 h. In addition, a relationship between the presence of high molecular mass and the ropiness of EPS from L. helveticus BCRC14030 was revealed.     

芽孢杆菌混合发酵工艺条件的优化

为提高饲料用芽孢杆菌中性蛋白酶的活力,考察了多种芽孢杆菌混菌发酵产蛋白酶的协同作用效果,并在单因素试验的基础上,采用响应面分析的中心组合试验设计对多芽孢杆菌的混合发酵工艺条件进行了优化。通过优化确定了混合发酵体系的最佳发酵条件为培养基最初pH值7.17,装液量50mL/250mL,接种量3%,发酵温度35.4℃,摇床转速200r/min,发酵周期100h。在优化的工艺条件下,芽孢杆菌混合发酵产蛋白酶的活力单位可达到2 986U/mL。     

益生菌发酵小米浆的工艺优化

以感官评分和菌落总数为评价指标,通过单因素及正交试验对煮制后小米浆的发酵工艺进行优化。结果表明,在浸泡、煮制并打浆后的小米浆中加入白砂糖6.5%、接种4%复合菌种（鼠李糖乳杆菌∶植物乳杆菌=1∶1）、37 ℃条件下发酵28 h,获得的发酵小米浆感官评分和活菌数都较高,分别为87.81分、8.79 lg（CFU/mL）。且发酵后的小米浆还原糖含量、总酚含量、总矿物质释放率和氨基酸态氮含量分别由原来的0.28 g/100 g、0.13 μg/mL、1.28%、6.32 mg/100 g提高至0.66 g/100 g、0.75 μg/mL、5.43%、25.76 mg/100 g。     

Flavour and aroma of fresh basil are affected by temperature

Sweet basil (Ocimum basilicum L.) plants at the three‐leaf‐pair growth stage were grown in controlled environment rooms at 15 and 25 °C for 2 weeks. Analysis of volatiles from blended leaves by gas chromatography/mass spectrometry showed that the plants grown at 25 °C contained significantly more volatile oils than those grown at 15 °C. The total volatile oil content in fresh leaves was enhanced by 70%. Temperature also affected the composition of volatile oils. At 25 °C there was an accumulation of eugenol, which contributes to the characteristic taste of basil. Although there was no effect on the relative contents of linalool and 1,8‐cineole, the absolute contents in fresh leaves were significantly different. Sensory analysis showed that 18 out of 21 trained sensory panellists perceived different intensities of volatile oils in fresh basil leaves from the two sources of plants. In addition, a simple consumer preference test conducted with basil users showed a significant preference for the stronger intensity (41 out of 64 consumers). Copyright © 2007 Society of Chemical Industry     

液体发酵竹红菌素提取工艺的研究

采用响应面分析法探讨了菌丝体内竹红菌素最佳提取工艺,研究结果表明:56℃条件下以1/4的料液比浸提2.2h,然后以8/1的料液比在40～50℃温度下两次洗涤中间体,每次10min的效果最佳,竹红菌素的提取率可达到1.72%。     

HPLC法监测香兰素的发酵合成

建立了同时监测发酵液中香兰素、香兰素酸、香兰素醇和阿魏酸的高效液相色谱法(HPLC).色谱柱为Eclipse Zorbax XDB-C18(4.6mm × 150mm,5μm),流动相为甲醇:水:冰醋酸(35:65:0.05),流速为0.80mL/min,检测波长为260nm和280nm.在此色谱条件下,四种物质获得良好的分离,且在一定浓度范围内,各组分的线性关系、方法的精密度和回收率都令人满意.     

大米生料发酵产乙醇工艺条件优化

选取大米生料发酵过程中的主要因素,以发酵结束后的乙醇含量为评价指标,通过单因素试验和正交试验,对大米生料发酵产乙醇的工艺条件进行了研究。结果表明,大米生料发酵产乙醇的最佳工艺条件为原料颗粒度50目,料水比1∶3.0（g∶mL）,α-淀粉酶添加量10 U/g,糖化酶添加量200 U/g,酸性蛋白酶添加量30 U/g,酵母液接种量1%,硫酸铵添加量0.8%。在此优化工艺条件下,乙醇含量为10.89%。     

Inhibition of dipeptidyl peptidase IV (DPP-IV) by proline containing casein-derived peptides

Dipeptides with a C terminal Pro inhibit dipeptidyl peptidase IV (DPP-IV), a key enzyme in incretin hormone processing. It was hypothesised that tri- and tetrapeptides with a proline at the C-terminus may also be DPP-IV inhibitors. Therefore, an in silico hydrolysis approach was used to release short (4 ? amino acids) C terminal Pro peptides from the individual caseins which constitute Pro rich substrates. This was achieved using theoretical digestion of caseins with a prolyl oligopeptidase activity. Fifteen peptides were subsequently selected for in vitro DPP-IV inhibitory analysis. Stability of these peptides to gastrointestinal enzymes was also evaluated in silico and the predicted breakdown peptides were assessed for their DPP-IV inhibitory and antioxidant potential. New DPP-IV inhibitors were identified, the most potent being Phe-Leu-Gln-Pro (IC₅₀ 65.3 ± 3.5 μM). A low in vitro antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging) activity was also associated with the peptides studied. The strategy presented highlights the utility of employing an in silico approach for the prediction of food-derived peptides with a potential role in glycaemic management for subsequent development of functional foods.     

超声辅助细胞转型的谷氨酸发酵工艺

为了进一步提高谷氨酸菌体细胞膜的通透性和谷氨酸产量,采用超声辅助谷氨酸发酵。通过单因素及正交实验研究,确定了最佳超声条件为超声时间50 s、振幅65%、间隔时间5 min,发酵起始,即开始超声处理至发酵8 h,结束超声。在最佳超声条件下进行谷氨酸发酵,菌体OD(600 nm)值为82. 5,提高13. 8%,谷氨酸产量为168 g/L,提高11. 3%,糖酸转化率为68. 2%,提高4. 3%,菌体转型时间由4 h提前至2 h。超声辅助谷氨酸发酵能够达到较好的效果,使发酵过程更加稳定。     

电解法制备超细铜粉的工艺研究

采用脉冲电解法,在硫酸铜与硫酸混合电解溶液体系中,就不同脉冲电解参数对阴极铜粉形貌和粒度的影响进行了研究.实验获得合适的脉冲参数为平均电流密度i=600 A/m2,脉冲宽度ton=8ms,占空比为1∶3,在此条件下,所得铜粉平均粒度为0.87μm,有90%颗粒粒径小于1.25μm,阴极沉积出的铜粉颗粒粒度在0.24~1.79μm之间,粒度分布均匀.     

Beneficial health effects of polyphenols metabolized by fermentation

Food Science and Biotechnology - High daily intake of polyphenol-rich meal in some countries could be regarded as a healthy meal. However, the knowledge about the bioavailability and functionality...     

响应面法优化酸马乳发酵工艺的研究

以酸马乳中乳酸菌活菌数为评价指标,研究了不同发酵条件对酸马乳中乳酸菌活菌数的影响,在单因素的基础上采用响应面试验优化酸马乳的发酵工艺条件。结果表明,酸马乳最佳发酵条件为：干酪乳杆菌∶乳酸乳球菌∶酵母菌=1∶1∶2,接种量6%,发酵时间48 h,发酵温度32 ℃,不添加蔗糖。在此最佳条件下,酸马乳中乳酸菌活菌数对数值可达8.673 9,酵母菌活菌数对数值为7.628 4,酸度6.34 g/L,酒精度1.2%vol。     

Biochemical properties of type I sourdough affected by wheat bran dietary fibre during fermentation

The supplementation of dietary fibre in sourdough is beneficial to increase the nutritional quality of fermented foods. The influence of different wheat bran dietary fibre (WBDF) levels (0%, 3%, 6%, 9%, and 12%) on the biochemical characteristics of sourdough during fermentation was investigated. This study showed that WBDF was slightly resistant to the reduced pH caused by the initial fermentation of sourdough dough. After 6 h of fermentation, whether or not it contained WBDF, the dough’s amylase activity was relatively stable (P > 0.05). However, in the samples containing WBDF, it took longer for the amylase activity to increase from 200 to 300 U g⁻¹. The content of free amino acids in the dough showed a tendency to first decrease and then increase with the metabolic activity of microorganisms, and WBDF could accelerate this rate. This study also provided evidence that insoluble dietary fibre may stimulate the growth and reproduction of lactic acid bacteria.     

酵母菌混合发酵制备米酒及其工艺优化

为了降低米酒的高级醇含量,提高米酒品质,以异常威克汉姆酵母（Wickerhamomyces anomalus）、扣囊复膜酵母（Saccharomyces fibuligera）和酿酒酵母（Saccharomyces cerevisiae）为菌株混合发酵制备米酒,对其挥发性风味物质及感官品质进行分析,并采用单因素试验及响应面试验对其发酵条件进行优化。结果表明,W. anomalus、S. fibuligera、S. cerevisiae按1∶1∶1比例制备米酒品质较好,米酒高级醇含量为164.95 mg/L,感官评分为87.3分。米酒最优发酵工艺条件为：接种量3×106 CFU/mL、后发酵温度21 ℃、后发酵时间2.5 d。在此优化条件下,米酒感官评分为90.1分,高级醇含量为153.1 mg/L,与优化前相比,其高级醇含量下降了7.2%,感官品质有所提高。     

菌酶协同发酵豆粕工艺的优化

为了提高豆粕饲料的品质,采用菌酶协同方法发酵豆粕。筛选了最优植物乳杆菌和蛋白酶,通过单因素及正交试验对发酵条件进行了优化。实验结果确定了1株产酸多、谱宽的植物乳杆菌DY6作为发酵菌株;选择中性蛋白酶进行酶解;确定了最佳发酵条件为菌液接种量5%,最佳加酶量1 250 U/g,最佳发酵温度37℃,最佳发酵时间48 h;此工艺下的豆粕中粗蛋白质量分数为53. 1%,肽含量为107. 21 mg/g,总酸质量分数为2. 5%,蛋白质体外消化率为69. 8%;与未发酵豆粕相比,发酵豆粕中粗蛋白含量提高了6. 23%,肽含量提高了223%,总酸含量提高了1. 8%,蛋白质体外消化率提高了17. 85%。菌酶协同处理豆粕可以有效提高豆粕的各项指标,提升饲料品质,在生物饲料行业具有广泛应用前景。     

响应面法优化蜂蜜酒发酵工艺

以狼牙蜂蜜为原料,考察发酵液糖度、温度、pH值等参数对蜂蜜酒品质的影响。试验采用Box-Behnken试验设计和响应面法优化蜂蜜酒发酵工艺,确定最优的发酵条件。结果表明,当初始糖度为25 °Bx、发酵温度为25 ℃、pH值为5.0时所酿制蜂蜜酒的品质最佳,且产品具有蜂蜜独特的风味。     

序批式固定化菌液态发酵白酒工艺的研究

以高粱糖化液为原料,采用序批式固定化菌液态发酵白酒工艺,酒精发酵最佳时间为36 h。以总酸、总酯含量为评价指标,利用均匀设计试验方法,确定该工艺中固定化生香酵母、乳酸菌、己酸菌的最佳添加量。结果表明,得到液态发酵白酒的固定化菌株最佳添加量为生香酵母5.5%、乳酸菌1.0%、己酸菌3%,在此最优条件下,总酸和总酯含量分别为486.62 mg/L和258.28 mg/L,且所酿白酒中酯类物质和高级醇含量均符合液态法白酒的国家标准。该工艺缩短了酒精发酵时间,并且提高了白酒品质。