Production of cured meat color in nitrite-free Harbin red sausage by Lactobacillus fermentum fermentation

Lactobacillus fermentum was substituted for nitrite to produce cured pink color in a Chinese-style sausage. Treatments included inoculations (10⁴, 10⁶, and 10⁸ CFU/g meat) followed by fermentation at 30 °C for 8 h and then at 4 °C for 16 h. Control sausage (with sodium nitrite, 60 mg/kg meat) was cured at 4 °C for 24 h without L. fermentum. The UV–Vis spectra of pigment extract from L. fermentum-treated sausage were identical to that of nitrosylmyoglobin (NO-Mb) formed in nitrite-treated control. The NO-Mb concentration and the colorimetric a^* value of sausage treated with 10⁸ CFU/g meat of L. fermentum essentially replicated those in nitrite-cured meat. Free amino acid content in sausage treated with L. fermentum was greater and the pH slightly lower compared with the nitrite-cured control sample. This study showed that L. fermentum has the potential to substitute for nitrite in the sausage production.     

Improvement of Riboflavin Production by Lactobacillus fermentum Isolated from Yogurt

The riboflavin production by Lactobacillus fermentum isolated from yogurt was improved by inactivation of folE gene. Guanosine triphosphate (GTP) serves as the precursor for both folate as well as riboflavin biosynthesis. The folE gene of Lb. fermentum, which codes for GTP cyclohydrolase I was inactivated by the insertion of erythromycin resistance gene cassette through recombination and the riboflavin production by the parental and mutant strains were estimated. Inactivation of the folE gene involved in folate biosynthesis pathway resulted in enhanced level of riboflavin production by Lb. fermentum, since more amount of GTP molecules are made available for the GTP cyclohydrolase II mediated riboflavin biosynthesis pathway. In a chemically defined medium, the Lb. fermentum produced 2.29 mg L^?1 of riboflavin at 24 h of fermentation. Whereas the folE disrupted mutant Lb. fermentum GKJFE produced approximately 50% more riboflavin (3.49 mg L^?1) than that of the parental strain at 72 h of fermentation.     

肉用发酵菌株的筛选及其在低盐发酵香肠中的应用

该研究以蛋白酶、脂肪酶活性和抑菌活性筛选肉用发酵菌株,通过分子生物学技术对其进行鉴定,并将其应用于低盐发酵香肠中,通过感官、理化及微生物指标分析评价其应用效果。结果表明,筛选鉴定得到两株适用于肉类发酵、安全且具有蛋白酶及抑菌活性的菌株,分别为植物乳杆菌（Lactiplantibacillus plantarum）BR-12和木糖葡萄球菌（Staphylococcus xylose）H-1,其中菌株BR-12还具有脂肪酶活性,两菌株间无拮抗作用。菌株BR-12与H-1按2∶1和1∶5的比例接种制备的低盐发酵香肠pH下降迅速,肠杆菌数与挥发性盐基氮含量较低,感官评分较高,硬度适中,弹性好,呈特有的玫瑰红色,且两菌株接种比例为2:1时,品质更好,说明菌株BR-12和H-1复配发酵有利于提高产品安全性,改善低盐发酵香肠滋气味,可用于低盐香肠发酵。     

Absence of volatile N-nitrosamines in cooked nitrite-free cured muscle foods

Nitrite-free cured pork systems were prepared using the preformed cooked cured-meat pigment (CCMP) and sodium ascorbate. Absence of volatile N-nitrosamines in cooked nitrite-free systems was confirmed using a gas chromatography-thermal energy analyzer (GC-TEA) methodology. Similar results were obtained when cod, cod surimi or mixtures containing pork with 15 or 50% cod or cod surimi were used. However, counterpart samples cured with sodium nitrite (156 ppm) and sodium ascorbate (550 ppm) produced N-nitrosodimethylamine at 1·0 ppb levels or less. Results demonstrate that nitrite-free curing of meat and meat/fish systems containing the preformed CCMP is successful in yielding products devoid of volatile N-nitrosamines.     

乳酸菌发酵生产共轭亚油酸

以盐生植物紫花苜蓿籽油为底物,用嗜酸乳酸杆菌(Lactobacillus acidophilus)1.1854催化紫花苜蓿籽油中的亚油酸转化为共轭亚油酸(CLA)。通过单因素实验,分析了发酵过程中pH、预培养、苜蓿籽油的浓度和乳酸菌菌液浓度对生产共轭亚油酸的影响。实验结果表明,预培养时加入一定量的苜蓿籽油可提高CLA转化率,发酵pH6.4,苜蓿籽油浓度0.05%,菌浓度2.5%时CLA转化率较高。     

红曲菌发酵对广式腊肠颜色和蛋白质降解的影响

采用GIM3.439紫红曲菌发酵广式腊肠,研究红曲菌发酵对广式腊肠的色泽、p H、氨基酸态氮含量和感官品质的影响;运用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和高效液相色谱（HPLC）等方法对广式腊肠中蛋白质、肽、游离氨基酸进行检测,分析红曲菌发酵过程中广式腊肠蛋白质的降解,初步研究了红曲菌发酵对广式腊肠中游离氨基酸的影响。结果表明:红曲菌发酵能够加深广式腊肠的红色;在发酵6 h时,发酵组氨基酸态氮含量达0.14%;电泳结果表明,红曲菌发酵对水溶性和盐溶性大分子蛋白降解均有促进作用,能够增加产品中小分子肽及游离氨基酸的总量;游离氨基酸总量由580 mg/100 g增加到930 mg/100 g。红曲菌发酵不仅使产品色泽更加诱人,而且使发酵后腊肠滋味更加丰富、浓郁,提高了腊肠的感官品质和营养价值。      

酒精发酵过程中影响红葡萄酒颜色的五大因素

葡萄酒按颜色可划分为白葡萄酒、桃红葡萄酒和红葡萄酒。红葡萄酒颜色几乎包括了所有的红色,主要有宝石红、鲜红、深红、暗红、紫红、黄红、棕红、瓦红、砖红等。新红葡萄酒的颜色多呈紫红、鲜红、宝石红,伴随着葡萄酒的成熟,单宁与游离花色等结合,使酒体渐显黄色调,所以陈年红葡萄酒多为瓦红、砖红、棕红等颜色。近年来随着葡萄酒在中国的兴起,中国葡萄酒生产企业纷纷引进国外先进酿酒设备,采用先进的酿造工艺,所生产出葡萄酒的质量较以前有了极大幅度的提高,但国内葡萄酒多存在一种现象,就是红葡萄酒颜色偏浅,尤其是与进口红葡…     

植物乳杆菌纯种半固态发酵泡菜工艺条件的研究

对产细菌素植物乳杆菌P158纯种半固态发酵泡菜工艺条件进行了研究。采用正交试验设计,并应用模糊数学综合评判法进行感官评价,确定泡菜产品的最佳工艺参数。结果表明,产细菌素植物乳杆菌纯种半固态发酵泡菜的最佳工艺参数为:盐4%、糖3%、接种量0.1%、发酵温度34℃。在该工艺条件下,制备的泡菜产品口味纯正,品质良好,为泡菜发酵生产探索了一条新路。     

Optimisation of fermentation variables for conjugated linoleic acid bioconversion by Lactobacillus fermentum DDHI27 in modified skim milk

Effects of fermentation variables on conjugated linoleic acids (CLAs) biosynthesis of Lactobacillus fermentum DDHI27 in modified skim milk were evaluated. A total of 0.5 mg/mL was found to be the optimum linoleic acid concentration for maximum CLA production and this level was used in utilised for all successive experiments. The highest production of CLA isomers was detected at pH 6.0 when compared to other pH levels. Maximum biosynthesis of CLA isomers occurred during stationary growth (48 h) phase at all pH values tested. Validation of CLA isomers produced in selected samples was made by GC‐MS. These results indicate that these parameters strongly influence the CLA production capabilities of the strain.     

海带多糖提取工艺的研究及在鹅肉红肠中的应用

以市售海带为原料,采用热水浴提取法研究了提取温度、提取时间、提取液pH值以及料液比等因素对多糖提取量的影响.通过正交试验得出海带多糖提取工艺及对鹅肉红肠的加工工艺进行了研究.结果表明在料液比1g∶40mL的条件下的最佳参数为:提取温度90℃,提取时间4.5h(提取2次),提取液pH值8.0.在最佳参数组合下,多糖提取量为54.2mg/g.确定了鹅肉红肠的最佳配方为鹅肉∶肥肉为70:30,淀粉用量7%,海带多糖用量3%,从而加工成具有独特风味的红肠制品.     

1株高产生物膜发酵乳杆菌抗胁迫特性与全基因组分析

为探究高产生物膜发酵乳杆菌733的抗性机理,测定其对模拟人工胃肠液、酸、胆盐、温度和盐胁迫的耐受性以及有害代谢产物的分泌情况,同时对其全基因组进行测序分析。结果显示,高产生物膜发酵乳杆菌733在模拟人工胃肠液中的存活率分别为(98.1±0.5)%和(98.1±1.2)%,存活率较高,且不产生有害代谢产物;不同胁迫环境均会抑制菌株生长,而在某些特定条件下会刺激菌株产生应激响应以保证菌株活力;发酵乳杆菌733在经历不同环境胁迫时,主要对trxA、perR、ctsR和argR基因产生影响,而这些基因调控菌株抗逆性的作用方式还有待研究。     

植物乳杆菌发酵对金枪鱼碎肉酶解液挥发性物质的影响

金枪鱼主要用于生鱼片、鱼柳、鱼排和各类鱼罐头等产品的加工,加工过程中会产生下脚料,这些下脚料腥味较重,风味不佳,多被加工成饲料处理,经济价值较低。鉴于此,本实验研究植物乳杆菌发酵对金枪鱼碎肉风味的改善作用,利用电子鼻和气质联用（GC-MS）分别检测了金枪鱼碎肉酶解液未发酵以及发酵不同时间的风味变化情况。结果发现,植物乳杆菌发酵金枪鱼碎肉酶解液中呈腥味的乙醛未发酵时含量为11.51%,发酵72 h后含量低至检测限下;呋喃类低阈值且具有良好风味的化合物未发酵时含量为0.68%,发酵48 h达到最大含量5.31%。研究结果为金枪鱼下脚料的综合利用以及高值化利用提供了理论基础。      

具有潜在益生特性的发酵乳杆菌在豆乳中的发酵特性

选用分离自西藏、内蒙古和蒙古国自然发酵乳制品中的具有潜在益生特性的11株发酵乳杆菌分别发酵豆乳,在42℃发酵和4℃贮藏期间分别测定其菌落总数、pH值、滴定酸度、黏度、蛋白水解能力以及脱水收缩性指标,并在贮藏1 d时进行感官鉴评.结果表明,发酵期间,各发酵豆乳的pH值显著下降,而滴定酸度、黏度均显著升高(P<0.05);L.fermentumF6发酵豆乳产品无乳清析出,表面细腻,具有良好的拉丝性,其表现、气味以及风味总体得分显著高于其他发酵产品(P<0.05).因此,L.fermentum F6适合用于益生茵凝固型发酵豆乳的开发.     

固态发酵三七渣产红曲红色素的工艺条件研究

通过单因素及正交试验考察了装样量、接种量、培养温度、预处理时间、发酵时间对固态发酵三七渣产红曲红色素的影响。结果表明,发酵过程受工艺条件的影响较大,其中接种量、装样量、培养温度对发酵结果的影响均极显著（P＜0.01）,这3个因素以及它们之间的交互作用对发酵结果影响程度的排序为交互作用＞培养温度＞装样量＞接种量。最佳发酵工艺条件为接种量15%、装样量12.5 g、培养温度34 ℃、预处理时间40 min、培养时间12 d,在此优化条件下,红曲红色素色价可达14.53 U/g。     

一株发酵乳杆菌(Lactobacillus fermentium)对柠檬酸的发酵特性研究

本文讨论了一株能高效转化利用高酸性水果(如青梅)中柠檬酸的发酵乳杆菌菌株的发酵特性。结果表明,该菌株能在以柠檬酸为主要碳源和能源的基础培养液中进行发酵生长,在转化利用柠檬酸的过程中仅仅产生少量的乙酸和乳酸,因此能将培养液中可滴定酸含量降低50%以上。菌株对乙醇具有较高的耐受性,当培养液中乙醇浓度达到9%(V/V)以上时,菌株的生长和柠檬酸代谢也就受到明显的抑制;菌株对亚硫酸盐非常敏感,培养液中仅仅添加0.5 m M的亚硫酸钠后,菌株的生长和柠檬酸代谢将会被完全抑制。培养液中蔗糖的添加能促进菌株的生长和柠檬酸代谢,但在柠檬酸存在的情况下,该菌株对蔗糖的转化利用较弱,因此,发酵期间培养液中糖的总含量并没有出现明显的下降。     

酒精发酵工艺对干红葡萄酒色度的影响

为筛选出最佳的酒精发酵工艺条件,采用正交试验方法,研究工艺中不同辅料的添加对干红葡萄酒色度的影响。结果表明：各影响因素的主次顺序为酵母种类〉亚硫酸添加量〉果胶酶添加量,即A〉C〉B,最优酒精发酵工艺条件为A2B1C2,即添加酵母为BDX、果胶酶添加量为10mg／L、亚硫酸添加量为60mg／L时,效果最好。     

Protective role of Lactobacillus fermentum R6 against Clostridium perfringens in vitro and in chicken breast meat under temperature abuse conditions

Six bacterial species were evaluated to determine their inhibitory effects on Clostridium perfringens in vitro (brain heart infusion broth) and in situ (chicken breast meat) under temperature abuse conditions (4 ± 1 °C for 12 h, followed by 7 h at 28 ± 1 °C and then 4 ± 1 °C for 53 h). During abusive storage, rapid growth of C. perfringens from vegetative cell and spore inocula was observed, exhibiting a 2.68–3.37 log CFU/mL (or g) increase in bacterial counts. In the presence of Pediococcus pentosaceus P1 or Lactobacillus fermentum R6, the counts of C. perfringens remained unchanged in the samples containing vegetative cells at the end of storage (P < 0.05); for those containing spores, the germination and outgrowth were also effectively inhibited, decreasing in bacterial counts of > 1.9 log CFU/mL (or g) compared to those of the control (P < 0.05). The pH of chicken meat was slightly declined by 0.09 in the presence of L. fermentum (P > 0.05), and the inhibitory effect against C. perfringens was ascribed to non-acid antimicrobial substances. These results indicate a potential solution for bio-protecting chicken meat from C. perfringens growth.Industrial relevanceClostridium perfringens is a common pathogen that contaminates meat and meat products, but the organism cannot multiply under cold chain conditions at 4 °C. However, it was reported that temperature abuses commonly occurred during the transportation, storage or retail display of the food chill chain. During the abusive storage, C. perfringens could grow rapidly, which may lead to food poisoning. It is a serious problem for food safety.In this study, Lactobacillus fermentum R6 was found to show effective inhibition on both the growth of C. perfringens vegetative cells and the germination and outgrowth of its spores in chicken meat (P < 0.05) under temperature abuse conditions, and also it had a minimal effect on the pH of the meat (P > 0.05). The results reveal a potential technology for bio-protecting chicken meat from C. perfringens growth.