盐度对豆豉后发酵周期的影响

本实验通过测定盐度为12％,15％,18％的豆豉后发酵过程中的理化指标,由氨基酸态氮含量确定后发酵周期,从而确定其后发酵周期分别为12天,18天,21天。并通过对成熟产品质量综合评定,确定盐度为12％较为合适。     

乳酸菌对发酵豆豉品质的影响

目的研究4株不同乳酸菌对豆豉发酵产生氨基态氮含量、γ-氨基丁酸(γ-aminobutyric acid,GABA)以及挥发性成分的影响。方法将高密度培养后的4株乳酸菌:植物乳杆菌(Lactobacillus plantarum,LP)、发酵乳杆菌(Lactobacillus plantarum,LF)、嗜酸乳杆菌(Lactobacillus acidophilus,LA)、瑞士乳杆菌(Lactobacillus casei,LH)分别接入豆豉成曲进行发酵,与未添加乳酸菌的对照组作比较,测定发酵完成后氨基态氮含量、γ-氨基丁酸含量,并用气相色谱质谱联用法(gas chromatography-mass spectrometry,GC-MS)检测各豆豉挥发性成分。结果添加乳酸菌发酵的豆豉氨基态氮含量都高于对照组豆豉,以LF、LP、LA效果明显,其中LF最为明显,达到2.355 g/100 g;添加LH、LP发酵豆豉产GABA含量高于对照组豆豉,其中LH最高,达38.2 mg/g;LF豆豉共检测出风味物质46种,LP豆豉共检测出风味物质50种,LH共检测出风味物质58种,LA共检测出风味物质49种,对照组未添加乳酸菌豆豉共检测出风味物质60种。结论本研究的结果为开发保健型发酵豆制品,4株不同乳酸菌发酵豆豉的应用提供信息。     

乳酸菌与酵母菌联合发酵改善食品品质研究进展

乳酸菌和酵母菌广泛用于谷物、果蔬、豆制品、乳制品等食品的发酵,在食品工业中具有重要的地位。乳酸菌和酵母菌不仅可以分别用于食品的发酵,还可以组合使用对食品进行联合发酵。该文对不同乳酸菌与酵母菌的组合方式、相互作用,及其对食品品质的影响进行了分析和总结,表明乳酸菌和酵母菌联合发酵对食品的感官特征、贮藏时间等品质具有明显影响,对改善食品品质具有重要意义。该研究旨在为乳酸菌与酵母菌联合发酵改善食品品质中的应用提供参考,为传统发酵食品的改良与新型发酵食品的开发提供思路。     

保康传统发酵臭豆豉菌群结构及风味品质分析

以湖北保康传统发酵臭豆豉为研究对象,采用高通量测序技术分析臭豆豉中菌群结构,并对其风味品质进行分析。结果表明,该豆豉中共获得62 725 条有效序列,注释得到423 个操作分类单元,隶属于1 个细菌界、22 个门、48 个纲、83 个目、103 个科、124 个属、137 个种。在门水平上,厚壁菌门（97.04%）为核心优势菌门,在属水平上,芽孢杆菌属（94.39%）为优势菌属,在种水平上,副地衣芽孢杆菌（68.83%）、嗜热淀粉芽孢杆菌（19.17%）和斯密氏芽孢杆菌（4.02%）为优势种。基础品质分析结果表明,该豆豉水分含量为51.87%,pH 值为7.54,总酸、氨基酸态氮、粗蛋白和粗脂肪含量分别为0.36、0.39、38.94、22.07 g/100 g,符合国家标准要求。气相色谱-质谱联用（gas chromatography-mass spectrometry,GC-MS）技术分析得到该豆豉风味物质主要为吡嗪类、酮类和羧酸类化合物,相对含量分别为67.35%、10.30%和5.96%,其中2,5-二甲基吡嗪、2-丁基-3,5-二甲吡嗪和川芎嗪相对含量分别为19.59%、27.83%和17.61%,是保康传统发酵臭豆豉的特征风味物质。     

豆豉发酵工艺条件的优化及品质分析

实验以大豆为原料,接种直投式米曲霉制曲、发酵的方法,通过单因素和正交实验,研究了发酵温度、发酵时间、含水量对发酵过程产生氨基态氮的影响,确定了最佳的发酵工艺优化条件。实验结果表明温度35℃,含水量40%,时间15d为最优发酵条件。在此条件下,对豆豉进行感官及化学指标测定,结果表明发酵后的豆豉氨基氮含量增加了5倍,总糖含量提高了1.3倍,而蛋白质的含量下降了27%。     

云南省普洱市传统发酵豆豉微生物的群落多样性

豆豉采自云南省普洱市,使用不依赖培养的方法并结合焦磷酸高通量测序分析了豆豉中微生物群落多样性。结果表明,豆豉中的细菌都属于厚壁菌门,主要的优势细菌是嗜盐四联球菌(Tetragenococcus halophilus),其次是葡萄球菌属(Staphylococcus)。豆豉中的真菌都属于假丝酵母属(Candida),丰度最高的真菌是Candida etchellsii,其次还有Candida apicola和Candida versatilis。所有的真菌和嗜盐四联球菌都是耐盐菌,它们在豆豉中的优势地位显示了普洱豆豉高盐的特点。葡萄球菌属的检出,暗示了豆豉可能存在一定的食品安全隐患。     

快速发酵豆豉关键技术及问题讨论

本文介绍了快速发酵法生产豆豉的工艺及关键技术,并且就生产中容易出现的质量问题进行了探讨,也介绍了该法所生产豆豉的质量标准.     

发酵处理对豆豉抗氧化活性影响的研究

发酵处理基本上不改变豆豉中异黄酮的总含量,而糖苷型大豆异黄酮在β-葡萄糖苷酶的作用下部分转化为游离型大豆异黄酮,使游离型大豆异黄酮的含量明显提高;在样品未添加任何抗氧化剂的前提下,通过试验发现豆豉的自身抗氧化性比原料熟黑豆强许多。     

传统霉菌发酵与接种发酵豆豉风味物质的比较分析

对接种发酵制作的豆豉香气成分进行分析检测,并与传统自然发酵豆豉和纯种米曲霉发酵的豆豉进行比较,经GC-MS分析,一共鉴定出了烃类、醇类、醛类、酮类、酸类、酯类、杂环化合物、含硫化合物、酚类以及其他化合物共10 类,152 种挥发性成分;结果表明,混合菌种发酵豆豉所含的烃类、醛类和酸类物质均高于纯种发酵培养,而传统自然发酵产生的醇类、杂环化合物、含硫化合物、酚类以及其他化合物都高于纯种发酵及混合菌种豆豉,而混合菌种发酵豆豉在酮类和酯类化合物要明显高于纯种米曲霉豆豉和传统自然发酵豆豉。     

添加阳江豆豉对广式腊肠品质的影响

以广式腊肠为研究对象,通过添加阳江豆豉研究其对广式腊肠品质的影响。首先对豆豉的基本成分进行分析,其次对添加豆豉腊肠组与未添加豆豉腊肠组的基本成分、色泽、质构、感官评定、酸价进行比较。结果表明:添加豆豉后,腊肠的蛋白质、脂肪、p H没有显著性差异(p0.05),蛋白质由25.27g/100g降至24.43g/100g,脂肪由43.78g/100g降至43.05g/100g,p H由5.80降至5.73;色泽方面,添加豆豉后,颜色变暗;质构方面,硬度、黏性、咀嚼性均降低,而弹性无显著差异(p0.05);感官评定方面,添加豆豉组的腊肠口感及风味评分较高;酸价方面,添加豆豉组的腊肠酸价低于未添加豆豉组。此结果表明豆豉有利于改善广式腊肠的食用品质并延缓其氧化。     

混菌发酵豆豉中异黄酮含量及对小鼠肺癌细胞的抑制作用

选用高产蛋白酶菌株枯草芽孢杆菌D2和β-葡萄糖苷酶产生菌枯草芽孢杆菌U35进行单菌种、混合菌种发酵生产豆豉,测定大豆异黄酮含量及其抗肿瘤能力,分析异黄酮含量和抗肿瘤能力的关系。用HPLC法测定豆豉提取物异黄酮含量,采用MTT比色法检测异黄酮含量对细胞增殖的影响,并在荧光显微镜下观察小鼠肺癌(LLC)细胞形态变化。结果表明,D2U35混菌豆豉苷元型异黄酮含量分别比D2、U35单菌豆豉高101.95μg/mL(2.38倍)和35.48μg/mL(1.25倍),D2U35混菌豆豉对肿瘤细胞的抑制率分别比D2、U35单菌豆豉高15.79%和7.02%,说明混菌发酵不仅提高了苷元型异黄酮含量,还提高了豆豉提取物的抗肿瘤能力。对肿瘤抑制作用,苷元苷型异黄酮>总异黄酮>糖苷型异黄酮。     

Effect of fermented rice culture on the microbiological,biochemical and sensory characteristics of low‐salt douchi,a traditional Chinese fermented soybean condiment

A low‐salt (4% NaCl, w/w) douchi supplemented with different concentration of fermented rice culture (FRC) of 0%, 5%, 10%, 15% and 20% (v/w) was produced, and the effect of FRC on microbiology, biochemistry and sensory quantity was investigated. Results indicated that FRC had a significant effect on low‐salt douchi. Compared with the control (added 0% FRC), in the other treatments, the counts of yeast and lactic acid bacteria increased by about 50%, whereas the moulds decreased by about 30%; the pH reduction was close to 4.7; total acid increased to about 1.300 g per 100 g; reducing sugar maintained a decrease to 21.07 mg per g; amino nitrogen increased to about 0.900 g per 100 g, but not above the control (1.013 g per 100 g). In general terms, total free amino acid contents and three organic acids were higher in low‐salt products than four commercial products. Sensory evaluation of products supplemented with 10% and 15% FRC revealed better overall acceptability compared with other treatments and a commercial product.     

豆豉发酵中微生物及其功能研究进展

介绍了毛霉型豆豉、细菌型豆豉、根霉型豆豉和曲霉型豆豉在制曲及后发酵过程中主次要微生物的分布、所含酶系及成品中不同的风味物质,并分析了不同豆豉中的主次要发酵微生物群系与其之间的作用。     

Histamine formation by histamine-forming bacteria in douchi,a Chinese traditional fermented soybean product

Seven soybean and 19 black bean douchi products sold in the supermarkets in southern Taiwan were purchased and tested to determine the occurrence of histamine and histamine-forming bacteria. The levels of pH, salt content, water content, yeast and mold, and aerobic plate count (APC) in all samples ranged from 4.7 to 5.9, 4.4% to 14.0%, 6.8% to 51.6%, 3.0 to 5.1 log CFU/g, and 5.2 to 9.2 log CFU/g, respectively. None of these samples contained total coliform and Escherichia coli. Although black bean douchi products had an average histamine content of 29.0 mg/100 g, 18 of them had histamine contents greater than 5 mg/100 g, the allowable level set by the US Food and Drug Administration (FDA) for scombroid fish and/or products. In contrast, only four soybean douchi products had histamine levels greater than 5 mg/100 g. Among the black bean samples, four contained histamine at 56.3, 62.1, 80.2 and 80.8 mg/100 g, that are above the 50 mg/100 g hazard action level. Eight histamine-forming bacterial strains, capable of producing 11.7–601 ppm of histamine in trypticase soy broth (TSB) supplemented with 1% l-histidine (TSBH), were identified as Bacillus subtilis (four strains) Staphylococcus pasteuri (one strain) and Staphylocuccus capitis (three strains) by 16S rDNA sequencing with PCR amplification. S. capitis, which was previously reported to be halotolerant, was a potent histamine-former capable of producing more than 500 ppm of histamine in TSBH in the presence of 0.5–10% NaCl.     

Angiotensin I-converting enzyme inhibitory peptides in douchi,a Chinese traditional fermented soybean product

Douchi, a soybean product originating in China, produces angiotensin I-converting enzyme (ACE) inhibitors with the potential to lower blood pressure. The ACE inhibitory activities of douchi qu pure-cultured by Aspergillus Egyptiacus for 48 h, and 72 h were compared with douchi secondary-fermented for 15 d. The results showed that ACE inhibitory activities were improved following the fermentation. ACE inhibitory activities of 48 h-primary-fermented douchi qu did not change dramatically after preincubation with ACE, but increased greatly after preincubation with gastrointestinal proteases. The results suggest they were pro-drug-type or a mixture of pro-drug-type and inhibitor-type inhibitors. The ACE inhibitors in 48 h-fermented douchi qu were fractionated into four major peaks by gel filtration chromatography on Sephadex G-25. Peak 2, which had the highest activity, had only one peptide, composed of phenylalanine, isoleucine and glycine with a ratio of 1:2:5.     

Effect of brine replacement and salt concentration on the fermentation of naturally black olives

This study was undertaken to modify the traditional fermentation of naturally black olives in order to obtain higher quality black table olives. After holding olives in tap water or low salt brine prior to fermentation, acidification of the cover brine and fermentation at two different salt concentrations (6 and 14 g/ 100 ml NaCl) were applied to Gemlik variety olives in three batches. Fermentations were monitored using physical, chemical and microbiological analyses and effects of the above changes to fermentation were investigated. Yeasts were the predominant microorganisms in all of the batches. Growth enhancement of lactic acid bacteria by brine replacement occurred in the fermentation with 6 g/ 100 ml NaCl cover brine but not with 14 g/100 ml NaCl brine. The highest level of titratable acidity (0.59 g/100 ml) formed during fermentation with 6 g/100 ml NaCl brine followed by fermentation with 6 g/100 ml NaCl brine (0.43 g/100 ml) where the brine was replaced after 48 days. The lowest level of titratable acidity (0.36 g/100 ml) was formed using a high salt brine. Reducing sugars were consumed effectively by microorganisms in all the batches and residual levels in the brines were 0.05–0.1 g/100 g ml. NaCl contents of the final products were 5.20 g/ 100 g (olives with high salt brine) and 3.27–3.58 g/100 g (olives with low salt brine). Moisture contents of the processed olives were in the range 49.58–50.79 g/ 100 g. The water activity (a_w) value of olives fermented with the high salt brine was found to be 0.947 while a_w values of olives fermented with the low salt brine were 0.962–0.964. Protein content of the olives ranged between 1.76–1.95 g/100 g and the ash contents were found to be 2.41–2.81 g/100 g in olives with low salt brine and 4.70 g/100 g in olives with high salt brine. According to sensory evaluations of the final products, no differences between the treatments were found (P > 0.05).     

豆豉纤溶酶液体发酵生产条件的研究

研究了芽孢杆菌菌株WMIl发酵生产豆豉纤溶酶的条件．结果表明,最佳发酵条件为：氮源w（带鱼蛋白胨）=3％,w（酵母膏）=0．5％;碳源w（水溶性淀粉）=3％;无机盐的用量为w（K2HPO4）=0．6％,w（KH2PO4）=0．1％,w（MgSO4）=0．1％,w（CaCl2）=0．04％,c（MnCl2）=10^-4mol／L;w（青霉素）=0．01％;培养基pH=6．0,培养温度为37℃．在此条件下,纤溶酶活性可达2345IU／mL．