Effects of coagulant type on the physicochemical and organoleptic properties of Kashar cheese

Kashar cheeses were manufactured using different coagulants (calf rennet, chymosin derived by fermentation and proteases from Rhizomucor miehei and Cryphonectria parasitica) and ripened for 90 days. Use of different coagulants did not influence the dry matter, fat, protein, salt, pH, titratable acidity, total free fatty acids and texture profile analyses. The levels of water‐soluble nitrogen, 12% trichloroacetic acid‐soluble nitrogen, and for 5% phosphotungstic acid‐soluble nitrogen, the sensory properties were significantly influenced by the use of different coagulants. β‐casein was more hydrolysed in the cheese manufactured using protease from Cryphonectria parasitica than the other cheeses during 90 d of ripening.     

Physical and Chemical Changes in Fermented Peanut and Soybean Pastes Containing Kojis Prepared Using Aspergillus oryzae and Rhizopus oligosporus

Studies were made to determine and compare physical and chemical changes occurring during 90 days of fermentation of miso-like products containing peanuts and soybeans as well as a combination of these oilseeds. Two koji molds (Aspergillus oryzae and Rhizopus oligosporus) and two levels of NaCl (6 and 12%) were evaluated. The L color values decreased more rapidly in misos containing A. oryzae koji compared to misos containing R. oligosporus koji and changes occurred earlier in low-salt formulae than in high-salt formulae. The type of mold koji had no apparent effect on changes in viscosity. The free fatty acid content of misos increased dramatically during the first 4 days of fermentation. Misos containing A. oryzae koji had higher soluble nitrogen and free amino acid content in the final product than did those containing R. oligosporus kojis. Peanut miso products had higher soluble nitrogen contents than did respective soybean products; however, the type of oilseed had little effect on accumulation of free amino acids.     

Effects of rice koji inoculated with Aspergillus luchuensis on the biochemical and sensory properties of a sailfin sandfish (Arctoscopus japonicus) fish sauce

The effects of rice koji inoculated with Aspergillus luchuensis on the biochemical and sensory properties of fish sauce produced from sailfin sandfish (Arctoscopus japonicus) with different salt concentrations (10% and 20%) were investigated over 10 months. Fish sauces prepared from sailfin sandfish with rice koji and a low salt concentration had higher total nitrogen, amino nitrogen and total free amino acid than did those without rice koji or with a high salt concentration. Sensory evaluation of fish sauces prepared with rice koji and a low salt concentration found better taste, flavour and overall acceptance than those prepared without rice koji during fermentation (P < 0.05). The use of rice koji increased the total nitrogen, amino nitrogen and free amino acid and also enhanced the sensory qualities during fermentation. These results suggest that the use of rice koji can result in a low‐salt fish sauce with better flavour.     

低盐外加曲发酵潮汕鱼露的理化性质变化

以鳀鱼(Engraulis japonicus)为原料,在不同盐质量分数(10%,15%,20%,30%)和不同曲质量分数(0%,5%)条件下发酵30d,然后再增加盐量至30%后继续发酵180d,对整个发酵过程中的总可溶性氮(TSN)、氨基酸态氮(AA-N)、挥发性盐基氮(TVB-N)、pH值、非酶褐变指数、游离氨基酸组成、感官及色差变化进行分析。结果表明,低盐发酵及低盐外加曲发酵可加速潮汕鱼露发酵;与低盐发酵鱼露相比,低盐加曲发酵鱼露中TSN、氨基酸态氮以及主要氨基酸(谷氨酸、丙氨酸、赖氨酸)质量浓度有较大提高,其中加盐15%加曲5%工艺风味较好。     

发酵鳀制鱼露的理化与感官性质的变化

鳀鱼中添加30%的海盐(盐/鱼,w/w)后在(30±5)℃条件下自然发酵180d,再在50℃下保温7d。定期测定发酵液的pH值、总可溶性氮(TSN)、氨基酸态氮、TCA可溶性肽、总酸、总挥发性盐基氮(TVB-N)、三甲胺氮(TMA-N)、氨基酸组成、红色指数以及非酶褐变指数,并进行感官分析(QDA-test)。结果表明,鳀鱼露发酵过程中,TSN含量、TCA可溶性肽含量、氨基酸态氮、游离氨基酸含量、红色指数以及非酶褐变指数均随着发酵时间的延长而增加,而pH值则随着发酵时间的增加而减少。TCA可溶性肽含量在保温发酵后有明显增长,TVB-N、TMA-N含量与发酵时间不呈明显的线形相关关系。谷氨酸、赖氨酸、亮氨酸、缬氨酸和丙氨酸是鱼露中最主要的氨基酸。感官分析结果表明,鱼露发酵的后期阶段,在50℃短期保温可以起到加速风味成熟与降低不良风味的作用。     

发酵生产鱼酱油过程中生化特性研究

对鱿鱼加工过程中副产物进行回收利用,不仅提高鱿鱼的经济价值,还可以减少副产物引起的环境污染。本研究采用三种工艺条件利用鱿鱼加工副产物发酵生产鱼酱油,测定了发酵过程中总氮、总酸、氮转化率、pH值、氨基态氮、挥发性盐基氮(T-VBN)和蛋白酶活的变化情况,并对产品进行了感官评价。结果表明,发酵过程中总氮、氮转化率、氨基态氮和T-VBN不断增加,而pH值、总酸和蛋白酶活在发酵的不同阶段呈现不同的变化趋势,并且获得的鱼酱油风味鲜美,没有任何不良风味。     

Effect of Fermentation on Soluble Proteins and In Vitro Protein Digestibility of Sorghum, Green Gram and Sorghum-Green Gram Blends

Changes in pH, titratable acidity and proteins of meals of sorghum, green gram and sorghum-green gram blend (70:30, w/w) during fermentation at 25°C up to 5 days were monitored. The pH of fermenting meals decreased sharply with concomitant increase in the titratable acidity within 24 hr. The proteins, free amino acids, soluble proteins and in vitro protein digestibility markedly increased within 24 hr fermentation. Supplementation of green gram with sorghum decreased the acidity and improved the contents of crude protein, soluble proteins and free amino acids of fermented sorghum meal.     

Structural Complexity of the Nitrogen Source and Influence on Yeast Growth and Fermentation

The structural complexity of the nitrogen source strongly affects both biomass and ethanol production by industrial strains of Saccharomyces cerevisiae, during fermentation in media containing glucose or maltose, and supplemented with a nitrogen source varying from a single ammonium salt (ammonium sulfate) to free amino acids (casamino acids) and peptides (peptone). Diauxie was observed at low glucose and maltose concentrations independent of nitrogen supplementation. At high sugar concentrations diauxie was not easily observed, and growth and ethanol production depended on the nature of the nitrogen source. This was different for baking and brewing ale and lager yeast strains. Sugar concentration had a strong effect on the shift from oxido‐fermentative to oxidative metabolism. At low sugar concentrations, biomass production was similar under both peptone and casamino acid supplementation. Under casamino acid supplementation, the time for metabolic shift increased with the glucose concentration, together with a decrease in the biomass production. This drastic effect on glucose fermentation resulted in the extinction of the second growth phase, probably due to the loss of cell viability. Ammonium salts always induced poor yeast performance. In general, supplementation with a nitrogen source in the peptide form (peptone) was more positive for yeast metabolism, inducing higher biomass and ethanol production, and preserving yeast viability, in both glucose and maltose media, for baking and brewing ale and lager yeast strains. Determination of amino acid utilization showed that most free and peptide amino acids present, in peptone and casamino acids, were utilized by the yeast, suggesting that the results described in this work were not due to a nutritional status induced by nitrogen limitation.     

Physical,chemical and microbiological characteristics of fermented surimi with Actinomucor elegans

The physical, chemical and microbiological changes of surimi during surimi pehtze preparation stage, with Actinomucor elegans XH-22 (A. elegans XH-22) as fermentation starter, were investigated. Enzyme assay showed that A. elegans XH-22 could continuously produce protease and α-amylase on surimi surface. Texture profile analysis (TPA) indicated that fermentation for 48 h decreased pH and moisture content and modified the texture properties of surimi. Increases in amino nitrogen and trichloroacetic acid-soluble nitrogen (TCA-N) contents revealed obvious surimi protein degradation, which was further confirmed by size-exclusion HPLC analysis of surimi water soluble protein. Fermentation significantly increased the content of free amino acids and enriched special amino acids such as histidine, phenylalanine and glutamic acid, which could influence the nutritional and sensory properties of fermented surimi product. Considerable levels of aerobic plate count, spores and LAB were detected during the fermentation process. It is thus, from a public health point of view, advisable that the fermentation time in the first stage be controlled to be within 36 h. This research gives a new clue for improving the utilization of low-value fish.     

添加水产下脚料对蓝圆鲹发酵鱼露的影响

以缩短鱼露的发酵周期及有效利用水产下脚料为目的,在30℃保温及露天日晒条件下制备水产下脚料粗酶提取液添加的蓝圆鲹发酵鱼露,并与复合蛋白酶添加的发酵鱼露作比较。在发酵过程中,测定鱼露的pH 值、总氮、氨基酸态氮、水分活度以及无盐可溶性固形物等理化指标。结果表明,露天日晒条件下水产下脚料添加的鱼露发酵最好,经过80d 发酵后其总氮和氨基酸态氮含量分别达到2.03g/100mL 和1.44g/100mL。游离氨基酸组分分析结果显示,快速发酵鱼露的氨基酸比例与市售鱼露间存在差别,但感官评价结果表明最终产品在气味、滋味等方面都具有较好的可接受性。     

两种微生物水解脱淀粉小麦中蛋白效果的比较研究

为研究枯草芽孢杆菌（Bacillus subtilis）和米曲霉（Aspergillus oryzae）对脱淀粉小麦中蛋白质的水解效果,采用前发酵和后发酵获得发酵液,比较两种微生物培养过程中性蛋白酶活力和发酵液的pH值、可溶性无盐固形物、氨基酸态氮含量、氨基酸组成,并对其发酵液进行感官评价。结果表明,在最适前发酵工艺的条件下,枯草芽孢杆菌和米曲霉中性蛋白酶活力分别为1 060.82 U/g和908.02 U/g;两种微生物最终发酵液pH值为7.08和5.37,可溶性无盐固形物为15.60%和18.98%,氨基酸态氮含量为0.73 g/100 mL和0.75 g/100 mL,总游离氨基酸含量为4.35 mg/mL和9.04 mg/mL,蛋白质水解度为55.99%和59.71%。枯草芽孢杆菌发酵液中必需氨基酸的组成和比例更符合氨基酸模式谱,必需氨基酸与总游离氨基酸的比值（EAA/TAA）、必需氨基酸与非必需氨基酸（EAA/NEAA）的比值也高于米曲霉。感官评价结果显示,米曲霉发酵液好于枯草芽孢杆菌。     

葡萄糖对快速发酵虾头酱中组胺抑制的作用

为探讨葡萄糖对快速发酵虾头酱中组胺的抑制作用,提高其安全性,本论文以新鲜虾头为原料,采用外接微生物快速发酵工艺,分别向虾头酱中添加2%、4%和6%葡萄糖,检测了虾头酱发酵过程中组胺含量的变化。对虾头酱发酵期间的TVB-N含量、氨基酸态氮及pH的变化进行了探讨,通过比较理化指标、菌落总数以及感官评价分析虾头酱的品质。结果表明,葡萄糖的添加能显著降低组胺的生成,添加2%、4%和6%的葡萄糖分别能降低54.6%、57.2%和43.2%的组胺;葡萄糖的添加一定程度上促进了TVB-N的生成,增加了产品总糖含量以及降低了氨基酸态氮的含量和pH,但并不影响蛋白质、脂肪、水分及菌落总数的含量;感官评价表明,产品风味相似度较高,葡萄糖的添加能明显抑制产品的氨气味。因此,虾头酱中添加2%、4%和6%的葡萄糖能降低组胺含量以及减少氨气味,同时产品也保持较高的品质特性。     

Changes in the amino acid compounds of the wholecrop wheat during ensiling and after fermentation

Changes in amino acid fractions of chopped low-to-medium protein whole-crop wheat were studied at four stages of maturation and at two stages after a 24 h wilting period. Tests were carried out after an ensiling period of 90 days, and after a further 7-day post-fermentation aerobic exposure. Total amino acids contents in the dry matter during the fermentation period remained stable. Quantities of essential amino acids decreased during maturation and fermentation and remained stable during post fermentation aerobic exposure. The highest amino acid concentrations recorded in the fresh material were those of arginine, lysine, glutamic acid, alanine, leucine, glycine and aspartic acid. Free amino acids varied from a low level in the fresh material < 10% of the total amino acids to ca 65% after the aerobic process. Ammonia-N content increased in the silage and remained relatively stable on post fermentation aerobic exposure. The concentration of all free amino acids increased except arginine and glutamine during the ensiling period and post fermentation aerobic exposure. After wilting, an increase in free amino acids and a decrease in insoluble amino acids was recorded. The changes in concentration of 18 amino acids during ensilage and following post fermentation aerobic exposure are given.     

Chemical, microbiological and sensory changes associated with fish sauce processing

The production of sardine fermented fish sauce was replicated in the laboratory in order to study the chemical, microbiological and sensory changes associated with the process. Fish sauce were produced by incubating mixtures of sardine (Sardina pilchardus) at different concentrations of sodium chloride and glucose at 37 °C for 57 days. Changes in chemical composition (moisture, protein, fat contents), pH, total volatile basic nitrogen (TVB-N, mg N/100 g fish flesh), trimethylamine (TMA-N, mg/100 g fish flesh), thiobarbituric acid (TBA, mg malonaldehyde/kg fish flesh), water activity (aw), color measurement, total viable count, lactic acid bacteria count, yeast and moulds counts and sensory analyses were observed. The fish sauces with spices were determined lower bacteria counts than fish sauces without spices. The addition of glucose to the fish sauces caused a significant increasing in the bacterial counts. Staphylococcus aureus and yeast-mould counts were not detected during fermentation period. The use of spices in fermentation of sardine enhanced good color, aroma and taste.     

静磁场对发酵鱼露工艺的影响

为探究鱼露酿造的新工艺,以淡水鱼下脚料为原料,粉碎成鱼糜与80 g/L盐、沪酿3.042米曲霉制成的酱油曲混合后,在静磁场环境下培养发酵生产鱼露.在不同静磁场环境下40℃发酵30 d,通过测定鱼露发酵过程中氨基态氮、总氮、挥发性盐基氮、无盐固形物、总酸、pH值和非酶褐变的变化,分析静磁场环境对鱼露发酵工艺及其品质的影响...     

Ka-pi-plaa fermented using beardless barb fish: physicochemical,microbiological and antioxidant properties as influenced by production processes

Production of Thai fish paste Ka-pi-plaa fermented using beardless barb, Cyclocheilichthys apogon was monitored. The physicochemical, microbiological and antioxidant properties were compared after each process, that is autolysis, salting, sun-drying and fermentation. Colour parameters L* decreased while a* and b* increased during production (P < 0.05). The Ka-pi-plaa finished product presented an intense brown colour as shown with the increase in browning intensity (A₄₂₀). Contents of formal nitrogen, ammonia nitrogen and amino nitrogen showed continuous increase (P < 0.05) indicating the formation of peptides and free amino acids, which were verified by protein patterns. Populations of total, halophilic, proteolytic, lipolytic and lactic acid bacteria (LAB) generally increased. Halophilic bacteria grew rapidly after salting. LAB counts were correlated with the pH change. It was suggested that a few biochemical reactions occurred during production, including protein hydrolysis by microbial and fish proteases, lipid oxidation as presented by the increasing thiobarbituric acid reactive substances value, and Maillard reaction based on the determined precursors and products. Antioxidant activities generally increased during production particularly fermentation, suggesting Ka-pi-plaa possessed 2,2-diphenyl-l-picrylhydrazyl and 2,2-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) scavenging and metal chelating activities, and ferric reducing power. This study provides important information on the relationship among production steps, various properties and chemical reactions for fish fermentation.     

大黄鱼卵鱼露的发酵工艺

以大黄鱼鱼卵发酵鱼露为研究对象,分析其在发酵过程中接曲量、加盐量、温度等条件对鱼露pH、总酸、氨基酸态氮、挥发性盐基氮、脂肪、硫代巴比妥酸等理化指标的影响,并分析了发酵第30 d时氨基酸的含量.结果表明:在大黄鱼鱼卵鱼露发酵过程中,pH整体上呈波动现象,且总酸含量的变化与其一致;氨基酸态氮含量在发酵过程中呈上升趋势,且...     

Effect of mass and turning time on free amino acid,peptide-N,sugar and pyrazine concentration during cocoa fermentation

A response surface methodology (RSM) was used to determine the optimum condition for mass and turning time during cocoa fermentation. Mass and turning time were used as independent variables; concentrations of free amino acids, peptide-N, sugars and pyrazines were the dependent variables. The R² values for peptide-N, tetramethylpyrazine and total pyrazines were greater than 0·9. Both lower (10 kg) and higher (100 kg) cocoa mass together with lower (0 min) and higher (10 min) turning time gave products containing low concentrations of hydrophobic, total and other free amino acids, peptide-N, fructose, glucose and total reducing sugars; in contrast, those of acidic free amino acids gave higher concentrations. Trimethyl-, tetramethyl- and total pyrazines increased significantly (P<0·05) at higher mass (100 kg) and higher turning time (10 min). From the highest concentration of the important flavour precursors ie hydrophobic free amino acids, total reducing sugars and peptide-N, the recommended mass of cocoa beans and turning time for an optimum cocoa fermentation condition was 60 kg and 5 min, respectively. © 1998 Society of Chemical Industry.     

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.     

北虫草发酵过程中营养成分及代谢物变化研究

研究了北虫草摇瓶发酵过程中培养基营养成分及其代谢物质变化情况,测定了培养基的pH、总糖、还原糖和可溶性蛋白及游离氨基酸等成分含量,探明了北虫草菌体生长、多糖及虫草素生成规律。结果显示:随发酵时间的延长,发酵液的pH、可溶性固形物、总糖和还原糖含量均总体呈下降趋势;游离氨基酸含量呈先变化迟缓而后上升趋势;北虫草菌丝体及虫草素产量随时间延长先增加后下降;粗多糖含量总体略呈下降趋势。