Associative Growth of Lactic Acid Bacteria in Cabbage Juice

Combinations of Leuconostoc mesenteroides, Lactobacillus brevis, Pediococcus cerevisiae, and Lactobacillus plantarum were grown in sterile cabbage juice broth. The effects of culture interactions were determined by lag times, generation times, pH change, and total acidity measurements. Fresh filter-sterilized cabbage juice was a better medium than autoclaved cabbage juice, or refrigerated filter-sterilized cabbage juice. The addition of NaCl (2.25%) had a minimal effect on the cultures, except for L. mesenteroides, which was inhibited. In paired association studies, L. mesenteroides was inhibited by all the other cultures, conversely, L. plantarum and L. brevis benefited from most of the culture interactions.     

Antibacterial Activity of Cabbage Juice Against Lactic Acid Bacteria

Fresh juice of Cecile cultivar cabbage (Brassica oleracea) was inhibitory to the growth of four species (including seven strains) of lactic acid bacteria. Inhibition was eliminated when the cabbage was heated (steamed 10 min) before juice extraction. When Lcuconostoc mes-enteroides C33 was tested in juices of three other cultivars of cabbage, growth inhibition was invariably noted in fresh juices, but was variable in heated juices. Fresh cabbage juice (CJ) adjusted to higher initial pH (6.5–7.5) showed greater antibacterial activities than at pH 5.0 to 6.0. When pH 4.0 precipitate from fresh CJ was added to noninhi-bitory CJ (cabbage heated before extraction), antibacterial activity was restored. A heat-labile and pH-dependent factor seemed responsible for activating a precursor into an inhibitory compound.     

富硒乳酸菌发酵酸奶贮藏品质变化

为了研究富硒乳酸菌发酵酸奶贮藏期间的品质变化,对富硒乳酸菌发酵酸奶(富硒酸奶)与非富硒乳酸菌发酵酸奶(对照酸奶)的感官性状、理化指标以及两种酸奶4℃贮藏过程中的菌落总数、滴定酸度、黏度、保水性、色泽、抗氧化性和感官评分进行分析。结果表明,贮藏第1 d时与对照酸奶相比,富硒酸奶的pH较高,总固形物含量和硒含量较高(对照酸奶的14.3倍),颜色更偏红、偏黄。富硒酸奶的乳酸菌菌落总数在贮藏第7 d后高于对照酸奶(P>0.05),而整个贮藏过程中滴定酸度、黏度低于对照酸奶(P<0.05),持水性低于对照酸奶(P>0.05)。相同贮藏期内富硒酸奶的过氧化值低于对照酸奶(P>0.05),对DPPH自由基、ABTS⁺自由基的清除活性高于对照酸奶(P<0.05),二者的感官评分接近(P>0.05)。富硒乳酸菌发酵酸奶具有较高的抗氧化活性、较低的后酸化,更有利于贮藏过程中品质的保持。     

接种乳酸菌制作发酵型甘蓝泡菜过程的研究

试验以甘蓝为主要原料制作泡菜,通过向基质中接入乳酸菌发酵泡菜,以感官评分、总酸、pH和亚硝酸盐含量为指标,考察了影响接种乳酸菌发酵甘蓝泡菜的主要因素。通过单因素试验确定了乳酸菌接种发酵型甘蓝泡菜的最佳工艺条件。结果表明:乳酸菌在发酵过程中快速生长并产生乳酸,降低了泡菜发酵基质的pH值,泡菜基质中的蛋白质被分解成游离氨基酸,钙离子结合成无机盐,具有很高的营养价值。     

梨乳酸菌饮料的研制

以砀山梨汁和奶粉为原料,杀菌后接种乳酸菌混合发酵剂进行乳酸发酵,成为凝固型酸奶,进而调配成活性乳酸菌饮料。通过单因素和正交试验,得出梨乳酸菌饮料的优化条件:梨汁添加量为20%,加糖量10%,酸味剂用量0.15%,稳定剂用量0.4%。     

开菲尔粒中乳酸菌的分离方法研究

本文分别对开菲尔滤液和洗液中乳酸菌的分离方法进行了研究。结果表明:使用添加了0.5%山梨酸钾的乳清改良培养基,倾注法(划线法)厌氧培养乳酸菌分离效果较好,并且滤液中的菌株比洗液中的长势更好,活力更高。     

汾酒大曲中乳酸菌的调查研究

通过选择性培养基对清香型汾酒大曲中的乳酸茵进行计数。结果表明,将汾酒大曲贮存期从3个月增加到6个月,乳酸茵非但没有减少,反而略为增加;当贮存到6个月时,红心曲中乳酸菌数量最多,达到7．10x10^9cfu／g,其次是清茬曲5．33x10^9cfu／g,最后是后火曲2．42x10^9cfu／g。通过发酵类型实验发现,仅有菌株QR6产气为异型发酵乳酸茵,进一步通过提取分析16SrDNA将其鉴定为融合魏氏菌。     

乳酸菌茶饮料的研制

以乳酸发酵产品和绿茶汁为主要原料,研制出了乳酸菌茶饮料,并探讨了乳酸菌饮料与绿茶混合后,口味及色泽的最佳比例。     

甘薯活性乳酸菌饮料的研制

以甘薯浆和鲜牛奶为主要原料进行乳酸发酵,研制出一种组织均匀、口感细腻,即有营养又有保健功能的天然饮料,并通过正交试验确定了最佳工艺参数.     

乳酸菌细胞膜的冻干损伤

冷冻干燥会造成乳酸菌细胞膜的损伤,主要有机械损伤、溶质损伤、细胞膜渗透性损伤、DNA损伤;导致蛋白质变性失活、pH的动态平衡被破坏;以及细胞膜脂肪酸组成的变化。这些不同形式的损伤会使乳酸菌在生产过程中的存活率降低。因此,应该依据这些损伤机理提出一些相应的降低冻干损伤的保护措施。这些措施包括:选择将损伤降到最低的最佳冷冻速率;添加适宜的保护剂;改变乳酸菌的遗传性状使它们具有较强的冻干抵抗力;采用自然选择的方法筛选出适应冻干条件的优良菌株。