鲁氏酵母对米渣生酱油风味和抗氧化活性的增强效应

利用鲁氏酵母和曲霉联合发酵米渣制作生酱油,评价其对产品风味和抗氧化活性的影响。结果表明鲁氏 酵母可以提高米渣生酱油谷氨酸、5-甲基-2-乙基-4-羟基-3（2H）-呋喃酮、4-乙烯基愈创木酚含量,增强还原力、 1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率、总抗氧化能力和·OH清除率等体 外抗氧化活性。米渣酱醪发酵至pH 5.0时接种0.025%鲁氏酵母发酵的生酱油品质最好,发酵45 d时,总氨基酸和抗 氧化氨基酸质量浓度较未接种组分别提高了24.76%和40.73%,还原力达到5 830.43 μg VC/mL。米渣生酱油的挥发 油、色素和截留分子质量小于10 kDa的组分均具有明显的DPPH自由基清除活性,并且呈现一定的量效关系。     

米渣生酱油抗氧化活性与发酵温度的相关性

米渣生酱油具有明显的抗氧化活性。采用还原力、对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、金属螯合能力和抗脂质过氧化能力等体外抗氧化活性为评价指标,探究了发酵温度与米渣生酱油的抗氧化活性的相关性,并利用Folin-Ciocalteu法、高效液相色谱(High Performance Liquid Chromatography,HPLC)法等对生酱油中总酚、5-羟甲基糠醛(5-hydroxymethylfurfural,5-HMF)等抗氧化活性成分进行分析,以阐明发酵温度对米渣生酱油中抗氧化活性成分的影响规律,从而阐释其抗氧化机制,并应用于猪肉保鲜试验。结果表明,米渣生酱油的还原能力、金属螯合能力以及抗脂质过氧化能力均随发酵温度的升高而增强,而对DPPH自由基清除能力顺序为50℃20℃35℃;抗氧化活性成分的变化规律与抗氧化活性变化规律相同,均以50℃发酵的米渣生酱油含量最高,其中50℃发酵时5-HMF含量显著高于35℃和20℃,对米渣酱油抗氧化活性有重要贡献。综合分析,在一定温度范围内,高温发酵有利于提高米渣生酱油的抗氧化能力,并通过抗氧化增强食品的保鲜效果。     

米渣生酱油和大豆生酱油的风味表征及比较

对3种不同菌种发酵的米渣生酱油和一种大豆生酱油的风味进行比较,以阐释鲁氏酵母、植物乳杆菌参与发酵对米渣生酱油风味的影响以及米渣生酱油和大豆生酱油的风味差别。结果表明单菌种发酵的大豆生酱油及鲁氏酵母和植物乳杆菌分别参与发酵的米渣生酱油游离氨基酸含量、味道强度值、挥发性风味成分及相对含量均明显高于米曲霉单菌种发酵的米渣生酱油,鲁氏酵母参与发酵的米渣生酱油中4-乙烯基愈创木酚相对含量达9.71%;电子舌呈味分析表明4种生酱油的主成分存在明显差异,鲁氏酵母参与发酵的米渣生酱油和大豆生酱油呈味非常相似,鲜味突出而酸味相对较弱,植物乳杆菌参与发酵的米渣生酱油各种味道相对均衡,综合感官质量最好。米渣酱油和大豆酱油的整体风味有一定差别,优化菌种耦合发酵明显有利于增强米渣生酱油风味。     

两种曲霉发酵米渣生产酱油的研究

本文介绍了以米渣为主要原料，采用曲霉进行圆态制曲，液态无盐发酵酿造酱油主要工艺流程，最佳种曲，成曲培养其配方和最适工艺条件。试验结果发明：发酵周期缩短至３－４天，原料全氮利用率达８０％以上，氨基酸生成率达５８％，本工艺适用可行，具有较高的社会和经济效益。     

米渣蛋白酱油发酵中氮素演变规律与过程调控相关性

本文以米渣蛋白(RDP)为主要原料酿制酱油,探讨发酵过程中氮素变化规律与过程调控的相关性。通过动态监测RDP酱油30 d的发酵过程中氨基态氮、总氮、可溶蛋白质、氮转化率的变化规律,优化酱醪的发酵温度、盐水浓度、盐水添加量等控制条件。对相同试验条件下所得RDP酱油和大豆酱油的氨基酸态氮和总氮含量进行了比较,并初步评价了RDP酱油的抗氧化活性。结果表明,50℃发酵2 d氮素转化即可达到最高值,35℃发酵持续时间长且有利于氮素转化,产品品质好;酱醪盐浓度为11%时有利于RDP的氮素转化;在盐水倍数为2.2、2.5、2.8时,对总氮和氨基态氮含量没有明显影响,但较高的盐水量可以促进RDP蛋白质的降解,有利于提高RDP酱油的总氮转化率。综合分析,确定RDP酱油发酵的优化控制条件为不超过35℃条件下添加2.8倍曲料质量的盐水,使酱醪盐浓度达到11%,可获得RDP总氮转化率70%以上的酱油产品。RDP酱油的总氮和氨基态氮含量均明显高于大豆酱油,RDP酱油具有显著的抗氧化活性。     

不同诱变方法对酱油发酵菌种性能的影响

采用不同的诱变方法(紫外、钴60、硫酸二乙酯化学诱变、连续诱变以及筛选诱变交替进行的连续诱变)对酱油发酵菌种米曲霉进行了诱变，并以蛋白酶为目标进行选育。讨论了诱变方法对菌株酶系分布的影响，以及不同诱变方法所得菌株对温度和水分的敏感性。     

米渣酱油与传统大豆酱油酿造过程的动态研究

以米曲霉HN 3.042为菌种,以米渣和大豆为主要原料酿造酱油,比较了二者制曲过程中蛋白酶的产生规律以及发酵过程中理化指标的动态变化规律,对所得的两种酱油进行感官评价,并利用GCMS分析和比较其挥发性芳香物质。研究表明:米渣酱醪的氨基态氮、总氮含量高于大豆,而可溶性蛋白、可溶性无盐固形物却均低于大豆,发酵31天,大豆酱油蛋白质利用率达到75.28%,高于米渣的66.85%;大豆酱油感官评分略高于米渣酱油,两种酱油中香气物质含量的差别较明显。米渣酱油是很有潜力的新品酱油,但其蛋白质利用率尚需进一步提高。     

米蛋白短肽抗氧化活性研究

以米渣为原料,通过蛋白酶酶解,并进行膜分离,得到米蛋白短肽。通过对样品蛋白分子量及短肽含量测定可知:米蛋白短肽分子量大部分集中在1 ku下,短肽含量为77.87%;并对米蛋白短肽抗氧化活性测定,结果显示:样品对样品对DPPH.、.O2-及.OH 3种自由基均具有一定清除能力,当米蛋白短肽浓度为10 mg/mL时,清除率分别为62.36%、82.07%、35.41%。     

从酱油生产用菌粉中选诱优良米曲霉菌种

以酱油酿造用菌粉为出发菌 (S) ,经分离、纯化后再经紫外线诱变 ( 3 0W ,2 5cm ,3 0min)及控温培养处理后 ,获得 1株变异菌株。结果表明 ,该菌株能在 42℃环境中旺盛生长 ;酶活力可达 72 63 5u/g(干曲 ) ,较出发菌株S酶活力提高了 1 0 8 3 %;遗传稳定性较好 ;发酵成酱油 ,其指标可达“GB1 81 86— 2 0 0 0低盐固态发酵酱油”特级品标准 ,明显优于出发菌株酿造的酱油     

发酵剂抗氧化活性对发酵肉制品品质的影响研究进展

发酵肉制品中脂肪的适度氧化能够赋予产品独特的风味,而脂肪和蛋白质的过度氧化则会对产品的风味、色泽、质地等产生不利影响,甚至产生有毒物质.天然和人工抗氧化剂因来源或安全性问题而使用受到限制,发酵剂作为发酵肉制品的生产原料其抗氧化能力逐渐受到关注.本文探讨了发酵肉制品中脂肪与蛋白质的氧化及发酵剂的抗氧化作用,同时概述了微生...     

米渣酱油多菌种制曲工艺研究

本研究以红曲霉、米曲霉、黑曲霉为菌种，以米渣、麸皮为原料，进行混合制曲，通过对制曲过程中糖化酶和酸、中性蛋白酶活力的变化分析，确定了混合菌种发酵米渣的最佳菌种配比、接种量及制曲时间，得出：米渣接入红曲霉培养4d后，最佳接种量及菌种配比为5％米曲霉＋5％黑曲霉混合菌种，制曲时间为2d。并通过四因素三水平正交设计方法确定了最佳pH、初始水分含量、原料配比、温度等制曲条件，其结果是：温度为31℃；米渣：麸皮=6：4；初始水分含量为35％及pH为5，在此条件下，糖化酶为4212U／g干曲，酸、中性蛋白酶活力分别为2130U／g干曲及2521U／g干曲。     

Antioxidant Activities of Compounds Isolated from Fermented Broth of Zygosaccharomyces Rouxii

Previously, a sugar-tolerant strain of Zygosaccharomyces rouxii that had moderate antioxidant activity was isolated. In this investigation four active substances were isolated and their antioxidant activity was determined with different methods. The yeast strain (MAFF 237555) was cultured in yeast extract-malt extract (YM) medium, and the fermented broth was extracted with ethyl acetate. Dried solid extract was separated into neutral and acidic fractions. The neutral fraction was fractionated on a silica-gel column and purified on a Sephadex LH-20 column. The acidic fraction was recrystallized from acetone. The mother liquor was fractionated on two successive silica gel columns, followed by purification on a Sephadex column. The combined active aliquots were further purified on ODS and Phenyl high performance liquid chromatography (HPLC) columns, successively. The chemical structures of isolated substances were analyzed by electron ionization mass spectrometry (EIMS) and nuclear magnetic resonance (NMR) spectroscopy and were identified as tyrosol, succinic acid, vanillic acid and para-hydroxy benzoic acid. Using available commercial compounds, we determined the antioxidant activity of isolated substances with seven assay methods was determined and compared to natural and synthetic standard compounds. It was observed that the activity of each substance varied with the assay mode. No single substance could be identified as an all-round highly active antioxidant, which was also true with the standard compounds. The diverse activities suggested that Z. rouxii could be used as a source of wide-spectrum natural antioxidant.     

Antioxidant Activities of Compounds Isolated from Fermented Broth of Zygosaccharomyces Rouxii

Previously, a sugar-tolerant strain of Zygosaccharomyces rouxii that had moderate antioxidant activity was isolated. In this investigation four active substances were isolated and their antioxidant activity was determined with different methods. The yeast strain (MAFF 237555) was cultured in yeast extract-malt extract (YM) medium, and the fermented broth was extracted with ethyl acetate. Dried solid extract was separated into neutral and acidic fractions. The neutral fraction was fractionated on a silica-gel column and purified on a Sephadex LH-20 column. The acidic fraction was recrystallized from acetone. The mother liquor was fractionated on two successive silica gel columns, followed by purification on a Sephadex column. The combined active aliquots were further purified on ODS and Phenyl high performance liquid chromatography (HPLC) columns, successively. The chemical structures of isolated substances were analyzed by electron ionization mass spectrometry (EIMS) and nuclear magnetic resonance (NMR) spectroscopy and were identified as tyrosol, succinic acid, vanillic acid and para-hydroxy benzoic acid. Using available commercial compounds, we determined the antioxidant activity of isolated substances with seven assay methods was determined and compared to natural and synthetic standard compounds. It was observed that the activity of each substance varied with the assay mode. No single substance could be identified as an all-round highly active antioxidant, which was also true with the standard compounds. The diverse activities suggested that Z. rouxii could be used as a source of wide-spectrum natural antioxidant.     

不同原料的米酒多酚及其抗氧化性能比较

为了更好地了解不同原料对米酒发酵过程中多酚及其抗氧化活性的影响,采用6种大米原料进行甜米酒的传统固态发酵工艺酿制.通过Folin-Ciocalteu法和高效液相色谱分别测定米酒的总多酚含量和主要酚类成分,根据ABTS自由基清除率和铁离子还原力(FRAP)检测米酒的抗氧化活性,并对米酒多酚含量与抗氧化性进行相关性分析,对...     

酱醪中耐盐酵母菌的分离鉴定及其耐盐性研究

为了改善酱油及鱼露发酵过程及风哧物质的产生,本文拟从自制高盐稀态酱醪发酵酱醪中分离纯化耐盐酵母,可作为产香酵母添加到酱醪或鱼露发酵过程。结果获得6株耐盐酵母菌,通过含3．0mol／LNaCl的固体培养基筛选出5#和6撑两株耐盐性较好、活力旺盛的菌株;经形态学、生理生化和18SrDNA鉴定,为鲁氏结合酵母。两株菌均耐盐性能强,且6#菌耐盐性能更优。     

米渣蛋白酿造酱油的原料配比优化

对米渣蛋白全替代大豆生产酿造酱油的原料配比进行了研究。以蛋白酶活、淀粉酶活为主要制曲指标,确定米渣蛋白最佳加入量为60%,其蛋白酶活达到2224U,淀粉酶活达到290U,发酵30天后,pH为6.18,氨基酸态氮含量为1.022g/dL,还原糖含量为3.518g/dL,色度为0.204。不同淀粉质原料对酿造酱油各项品质指标均有明显影响,炒小麦的蛋白酶活和氨基酸态氮含量最高,分别为2692U和0.936g/dL。面粉淀粉酶活最高,为380U;米粉还原糖含量最高,为4.93g/dL;蒸玉米的色度最高,为0.249。以氨基酸态氮含量和还原糖含量为主要发酵指标,可以确定蒸玉米为最佳淀粉质原料,以米渣代替大豆酿造酱油是可行的。