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。     

草鱼和鳗鱼内脏发酵鱼露的理化成分比较

以草鱼鱼露和鳗鱼鱼露为研究对象,研究鱼露发酵过程中理化成分(TVB-N、AA-N、pH、NaCl、脂肪、总糖等)含量的变化。在发酵的过程中,pH呈现下降趋势,鳗鱼鱼露略高于草鱼鱼露;AA-N呈先上升后略微下降的趋势,鳗鱼鱼露的含量高于草鱼鱼露;TVB-N呈先增加后趋于平稳的趋势,鳗鱼鱼露的含量略高于草鱼鱼露;NaCl略微有所上升,草鱼鱼露和鳗鱼鱼露相差不大;脂肪含量呈现下降趋势,草鱼鱼露和鳗鱼鱼露相差不大;总糖的含量呈现先上升后下降的趋势,草鱼鱼露的含量高于鳗鱼鱼露。     

鱼露及加工技术研究进展

介绍了鱼露发酵生产的基本情况,并从安全性、生物活性、风味以及快速发酵生产工艺4个方面说明发酵法生产鱼露的研究进展;特别说明了鱼露中存在致癌性前体成分———亚硝基化合物以及多种生物活性成分;介绍了目前对鱼露中挥发性成分和非挥性成分风味成分的鉴定研究情况,指出了快速发酵工艺给鱼露风味带来的负面影响。     

鱼露发酵技术的研究进展

统计了国内外鱼露相关研究概况,重点介绍了鱼露的快速发酵、风味改善、功能性研究及安全性保证等方面的研究成果,为鱼露的深入研究及其快速工业化、规模化、标准化生产提供依据。     

Accelerated Fermentation Process for the Manufacture of Fish Sauce Using Histidine

Addition of histidine accelerated hydrolysis of fish protein during fermentation in the manufacture of fish sauce and after 4 mo fermentation yielded a product typical of traditional fish sauce. The liquefaction rate of the histidine-treated sauce was faster than that of the control. The degree of hydrolysis was much greater in the histidine-added sauces than in the control. Most amino acids were higher in the histidine sauces compared to commercial patis sauce (as reference). Addition of histidine to the fish mixture during fermentation did not increase the histamine content of the sauces.     

低盐发酵鳀鱼鱼露过程中品质动态变化分析

实验以低盐发酵鳀鱼鱼露为研究对象,分析其发酵过程中微生物群落结构及理化指标的变化情况。研究结果表明:鱼露发酵过程中微生物菌群主要分布在厚壁菌门、变形菌门、拟杆菌门、酸杆菌门、放线菌门等;微生物菌群结构变化直接影响pH值、AAN值和TVB-N值的变化;挥发性风味物质含量随着发酵时间的延长呈现上升趋势,游离氨基酸总量和必需氨基酸总量与鱼露中微生物菌群结构变化有关,前期含量上升,后期趋于稳定。该研究明确了低盐发酵鳀鱼鱼露过程中微生物菌群与理化指标的联系,分析了其挥发性风味物质与游离氨基酸的变化情况,为低盐鱼露发酵工艺改良及相关研究提供了理论依据及方法借鉴。     

Oxygen Effect on Volatile Acids Formation During Fermentation in Manufacture of Fish Sauce

Volatile acids of aerobically and anaerobically fermented fish sauces were investigated using GC and GC-MS. There was no significant difference in pH values of the two types of sauces. Volatile acids found in the aerobically fermented sauce had concentrations significantly higher than the anaerobically fermented one. Sensory evaluation revealed that the aroma of the anaerobically fermented sauce was a little sweet, less acidic and less rancid than the aerobically made sauce which was sharp, and cheesy. Thus, fermentation under anaerobic condition altered the aroma quality of the sauce during manufacturing, yielding an acceptable product.     

多酶法在鱼露生产工艺中的应用

应用正交试验优选了碱性蛋白酶和中性蛋白酶对青鳞鱼下脚料 (鱼头、鱼骨、内脏、鱼皮等 )的水解条件 ,在此基础上 ,同时用碱性蛋白酶和中性蛋白酶 ,再用风味酶对青鳞鱼下脚料蛋白质进行水解 ,确定了以多酶法生产鱼露的新工艺。结果表明 ,青鳞鱼下脚料中蛋白质含量达 14 8% ,经多酶水解和适当调配可制得风味浓郁的鱼露。多酶法水解蛋白质的条件为 :同时用 1 5 %碱性蛋白酶和 1 5 %中性蛋白酶在 pH 7 0、5 0℃条件下水解 12 0min后再加入 2 %风味酶继续水解 60min ;新工艺生产鱼露中必需氨基酸含量达 40 3 % ,总氮达 19mg/L ,氨基氮达 11mg/g ,占总氮的 61 0 % ,呈味氨基酸含量达 49 5 %。因此新工艺鱼露营养丰富 ,味道鲜美。     

Purification and Characterization of a Halotolerant Alkaline Serine Protease from Penicillium citrinum YL-1 Isolated from Traditional Chinese Fish Sauce

A halotolerant alkaline serine protease from Penicillium citrinum YL-1 which was isolated from traditional Chinese fish sauce was purified by ammonium sulfate precipitation, dialysis, and DEAE 52-Cellulose column, thereby resulting in a 4.66-fold increase in specific activity (110.68 U/mg). The molecular weight (MW) was estimated to be 32.27 kDa using SDS-PAGE analysis. The protease exhibited optimal activity toward the substrate casein at pH 8.0 at 40°C and was stable at pH 6.0–8.0 and 4–30°C. Activity was inhibited by NaCl and retained at 28.3, 21.4 and 18.1% of the initial activity after incubation for 6 h at 20, 25 and 30% NaCl concentrations, respectively. The enzyme was stimulated by Mn²⁺ and inhibited by K⁺, Ca²⁺, Zn²⁺, Mg²⁺, Fe²⁺, and Fe³⁺. K_m and V_max of the protease for casein were 1.93 mg/ml and 56.81 μg/(min·ml), respectively. Protease activity was strongly inhibited by phenylmethyl sulfonylfluoride (PMSF), which confirmed the serine protease nature of the enzyme. The protease can hydrolyze tilapia protein in the absence or presence of NaCl (5–30%), thus suggesting that this protease is more halotolerant than the protease from other bacteria with high salinity resistance based on the current literature. These properties make the halotolerant alkaline serine protease a suitable candidate enzyme for fish protein hydrolysis during fish sauce fermentation.     

湘西传统酸鱼中乳酸菌的分离及特性研究

对从湘西传统酸鱼4个不同发酵阶段分离的196株乳酸菌种类进行了研究,分离出的乳酸菌主要包括植物乳杆菌、戊糖片球菌、食品乳杆菌、明串珠菌、肠球菌及干酪乳杆菌等,并且这些乳酸菌在发酵过程中呈现出一种动态的变化进程。同时对分离到的乳酸菌进行了一系列的生理生化试验;产酸速率实验,耐食盐、耐亚硝盐实验,耐酸及耐胆盐实验,氨基酸脱羧酶实验以及抑菌实验,选育出具有较好的发酵剂潜力的3株植物乳杆菌和1株戊糖片球菌。     

A Traditional Turkish Lactic Acid Fermented Beverage: Shalgam (Salgam)

Shalgam is a traditional lactic acid fermented beverage in which black carrot, bulgur flour, sourdough, salt, turnip, and water are used for production. It is a red coloured, cloudy and sour soft drink mainly consumed in southern Turkey, however, its consumption is currently increasing in other parts, as well. Shalgam is produced on an industrial scale. Although there is no standard production technique in industry, it could be stated that there are two methods for shalgam production: the traditional method and the direct method. The traditional method comprises sourdough fermentation and carrot fermentation. In the direct method, however, the sourdough fermentation is omitted and only the carrot fermentation is applied. During fermentation, mainly lactic acid bacteria give shalgam its typical taste and flavour by producing lactic acid, ethanol, and some other organic compounds. This article reviews some aspects of shalgam production.     

Effect of mixed kojis on physiochemical and sensory properties of rapid‐fermented fish sauce made with freshwater fish by‐products

The objective of this study was to investigate the effect of mixed kojis on essential indices of fish sauce. Fish sauce inoculated with mixed kojis (FSB, Aspergillus oryzae koji:Aspergillus niger koji = 3:1) and A. oryzae koji (FSA, control) was prepared. At the end of fermentation, the content of amino nitrogen, total soluble nitrogen, Free amino acid (FAA) and glutamic acid in FSB increased by 7.50%, 7.84%, 9.80% and 28.43% compared to FSA, due to higher acid protease activity in mixed kojis. Moreover, flavour groups including phenols, ketones and nitrogen‐containing compounds in FSB were also improved. According to the results of sensory evaluation, FSB showed higher intensity of umami and caramel attributes, lower intensity of ammonia and sour attributes. All the results suggested that the usage of mixed kojis to produce fish sauce was an effective method that can accelerate the fermentation process and improve the flavour of fish sauce made with freshwater fish by‐products.     

Changes in the chemical composition of traditional Chinese‐type soy sauce at different stages of manufacture and its relation to taste

Chemical composition of traditional Chinese‐type soy sauce (TCSS) at different stages of manufacture (moromi fermentation and pasteurisation) were analysed. Results showed that total nitrogen, formaldehyde nitrogen, total titratable acid, reducing sugar, NaCl, water soluble peptides, free amino acids (FAAs) and Maillard reaction products in TCSS changed significantly during manufacture. Most of FAAs were released during initial stage (0–15 days) of moromi fermentation, peptides (1–5 kDa) kept dominant (69.34–80.88%) among all peptides during manufacture and Maillard reaction products increased progressively during moromi fermentation and increased sharply during pasteurisation. According to hierarchical cluster analysis and sensory evaluation, there were obvious correlation between FAAs and sensory score of over‐all in TCSS during manufacture, which indicated that balanced FAAs composition might be mainly responsible for the taste formation of TCSS. Besides, pasteurisation can further improve the over‐all taste of TCSS.     

Microbiological and Chemical Changes During the Production of Acidic Whey,A Traditional Chinese Tofu-Coagulant

In this study, acidic whey (AW), a natural tofu-coagulant in China, was investigated for the micro flora and chemical changes of AW during tofu whey natural fermentation. The gel properties of AW tofu coagulated with AW were also studied. Throughout the fermentation stages, the change of lactic acid bacteria (LAB) was found to be similar to that of total mesophilic aerobic bacteria (TMAB), implying that LAB is the most important role that works on AW fermentation. The numbers of enterobacteriaceae, yeast and mould (fungi) were too low to detect. Bacterial spores (spores) and acetibacteria was found to increase slowly with fermentation time. The pH value, protein, carbohydrate, organic acid changes during the production of acidic whey were studied. It was found that the pH value of acidic whey had a significant effect on the gel properties of AW tofu. The microbiological findings in this study have clearly demonstrated the presence of the high counts of LAB investigated and a large amount L-lactic acid produced by LAB must have act as the main tofu coagulant.     

Comparative Study on Organoleptic,Microbiological and Chemical Qualities of Dried Fish,Goldstripe Sardinella(Sardinella Gibbosa) with Low Salt Levels and Spices

Dried fish is very important component in Sri Lankan fishery productswhile current domestic production is estimated at around 40,000 tons per year. Generally, dried fish production in Sri Lanka is based on traditional methodology where 30% of salt is used averagely. Use of excess amount of salt can have negative health effects. Therefore production of dried fish with low salt is very important.Accordingly, partial substitution of salt with alternative substances can be done. Current study aimed at evaluating the effect of low levels of salt and combined effect of low salt and spices on quality of dried fish. The study was carried out using eviscerated and cleaned up GoldstripeSardinella with 0% (T1), 5% (T2), 10% (T3) salt levels and two different combinations of salt and spices (1%salt with 0.2%turmeric, 0.5%chlli, 0.5%pepper (T4) and 2%salt with 0.2%turmeric, 0.2%chlli, 0.2%pepper (T5)). Hot air dehydrator (65-70 °C) was used for fish drying. Chemical (moisture, water activity (a_w), Total volatile nitrogen (TVN), and sodium chloride), physical (texture and rehydration), microbiological (APC, mould and yeast count and coliform count) properties and sensory attributes of experimentally prepared dried fish were investigated. The chemical parameters for all treatments were significantly different (p<0.05) while physical parameters were not (p>0.05). T2 indicated the best chemical quality. The values for moisture, a_w, sodium chloride, TVN, texture and rehydration for T2, were 11.6584±0.03, 0.591±0.002, 12.43±0.15, 59.43 mg/100g±12.86, 1.54kg±0.14 and 12.70±3.54 respectively. T2 and T3 had least microbial counts while T1 and T5 had highest microbial count. But T5 had highest scores for all sensory attributes indicating consumer preference for low salt and spicy taste regardless of high TVN content and poor microbial quality.Therefore it is essential to improve the methodology to enhance the quality of low salt and spices added dried fish.     

A New Type of Tea Pigment—From the Chemical Oxidation of Epicatechin Gallate and Isolated from Tea

( - )-Epicatechin-3-O-gallate (ECG), one of the major green tea poly-phenols, was oxidised chemically using potassium ferricyanide. The major oxidation product, termed theaflavate A, which gave a sharp peak on HPLC analysis, was separated and purified by a combination of chromatography on Sephadex LH-20 and a semi-preparative HPLC method. This compound was characterised by NMR spectroscopy (¹H, ¹³C, HMQC, HMBC and ROESY) and mass spectrometry (Electrospray method) and was found to have a novel benzotropolone skeleton formed between the B-ring of one ECG molecule and the galloyl ester group of another. Compounds containing this type of benzotropolone link were also found to be present in black tea. This benzotropolone link is of great interest, since it shows that the galloyl ester groups of flavan-3-ols participate in oxidative condensation reactions. This illustrates the complexity of theaflavin-type compounds in black tea and provides an additional reaction pathway for the formation of thearubigins which has not been previously considered. © 1997 SCI     

A Simple In Vitro Fermentation System for Polysaccharides—The Effects of Fermenter Fluid Surface Area/Fluid Volume Ratio and Amount of Substrate

A simple batch fermentation system for dietary non-starch polysaccharides using simple in vitro methods has been studied to identify if the position of the bottle (fluid surface area/fluid volume ratio) and shaking influence fermentation and bacterial mass. Shaking has no effect on the fermentation or bacterial mass increase. The amount of pectin, ispaghula or starch influences the result as does the surface to volume ratio. © 1997 SCI.