4种香辛料对泡菜发酵过程中乳酸菌生长的影响

研究了大蒜、茴香、生姜、辣椒 4种香辛料对蔬菜发酵过程中的主要参与菌种肠膜明串珠菌、植物乳杆菌生长的影响。香辛料经预处理后 ,以不同的添加量加入含大白菜的泡菜水中 ,经灭菌 ,分别接种肠膜明串珠菌、植物乳杆菌 ,3 0℃培养后 ,在波长 480nm处测定其OD值。发现大蒜、茴香、辣椒 3种香辛料对 2种乳酸菌的生长都具有明显促进作用 ,对明串珠菌的作用强于植物乳杆菌 ;2 %的辣椒和茴香效能最高。这一结果为进一步改进酸泡菜的生产工艺过程、延长产品的货架期、提高产品的质量提供了理论指导。     

乳酸菌胞外多糖的生理功能及其在食品中的应用

本文概述了乳酸菌胞外多糖的生理功能、生理活性的研究现状，介绍了乳酸菌胞外多糖在酸奶、干酪等产品上的应用及最新研究进展，展望了乳酸菌胞外多糖的研究开发前景和方向。     

Populations, types and biochemical activities of aerobic bacteria and lactic acid bacteria from the air of cheese factories

This investigation was carried out in order to identify the airborne bacteria in the processing rooms of two creameries that make, mainly, feta cheese and study some of their biochemical activities. Our results suggest that the numbers of airborne micro-organisms may differ between plants, and the same was observed with the predominant types. The bacteria isolated were primarily Gram-positive, catalase-negative cocci, micrococci and bacilli. The predominant lactic microflora were lactococci and mesophilic lactobacilli, commonly found in feta and other traditional Greek cheeses. A significant number of aerobic bacteria could grow at 4°C and in 6.5% NaCl. In addition, both aerobic and lactic acid bacteria (LAB) exhibited acidifying and proteolytic activities. Slow- and medium-acidification ability of LAB strains were found. There was also a tendency of the strains to preferentially degrade αs-casein. The amounts of amino acids accumulated in the milk were strain dependent. Therefore, there is a possibility that airborne bacteria contaminating cheese milk in the open vats may multiply and contribute to the ripening changes in the cheese.     

融合对比度和分布性的图像显著性区域检测

单独基于对比度的显著性检测方法由于忽略了特征的空间分布,且只在RGB空间或LAB空间下单独进行计算,故实验结果不理想。本文提出了结合RGB和LAB两种特征空间并融合了对比度和分布性的图像显著性区域检测算法。该算法首先提取图像分块在RGB空间和LAB空间下的原始特征并进行组合,在主成分分析（PCA）降维的基础上自动选择有效特征;然后计算图像分块的对比度和分布性,融合对比度特征和分布性特征实现对原始图像的显著性区域提取。实验结果显示,本文算法的平均准确率为0.821 7,平均召回率为0.692 5,综合指标F值达0.787 8。计算的显著性区域的效果比在RGB空间或LAB空间下单独基于对比度的计算方法有明显改善,相比其他检测方法更加准确,符合人眼的观测结果,均匀突出了显著性区域。     

发酵方式对蔬菜质构和抗氧化性的影响

研究了5%NaCl腌渍预处理、发酵温度对白菜和大蒜泥混合物质构和抗氧化性能的影响。结果表明,腌渍预处理可改善产品质构,处理后半固态发酵与固态发酵产品质构无显著差异。腌渍预处理后接种乳酸菌对混合物进行发酵,得到的产品其甲醇提取物浓度是8mg/mL时,还原力是α-生育酚和丁基羟基茴香醚(BHA)的1.2～1.6倍;浓度是2mg/mL时,半固态发酵产品的2,2-二苯代苦味酰基苯肼(DDPH)自由基清除力是76.1%,固态发酵产品的是80.5%。     

传统干酪中一株产IIa类细菌素乳酸菌的分离与鉴定

从内蒙古传统干酪中分离到一株产抑菌活性物质的乳酸菌M-2，其对单核细胞增生李斯特氏菌、金黄色葡萄球菌等食品中常见致病菌和腐败菌都有抑制作用。排除有机酸、H202等的干扰后，仍有抑菌活性：进一步硫酸铵沉淀、透析及浓缩处理后，其抑菌活性显著增强；用蛋白酶K处理后，其抑菌活性消失，因此确定该抑菌活性物质为蛋白类物质，进而确定乳酸菌M-2为细菌素产生菌。通过生理生化实验和16SrRNA基因序列分析对该菌株进行了鉴定。PCR扩增得到1675bp的16SrRNA序列，并将其通过BLAST软件在NCBI网站中进行同源性比，同时，通过Bioedit7．0和Treedrawing软件绘制系统发育树。结果显示，M-2的16SrRNA序列和数据库中的屎肠球菌SF菌株的序列的同源性为99．87％。在细菌系统发育分类学上，M-2菌株归属屎肠球菌（Enterococcus faecium）。这与生理生化实验初步鉴定结果一致。根据细菌素的分类原则，将该细菌素归类为IIa类细菌素。     

Inhibitors of lactic acid fermentation in Spanish-style green olive brines of the Manzanilla variety

Frequently, a delay or lack of lactic acid fermentation occurs during the processing of Spanish-style green olives, in particular of the Manzanilla variety. Many variables can affect the progress of fermentation such as temperature, nutrients, salt concentration, antimicrobials in brines, and others. In this study, it was demonstrated that an inappropriate alkaline treatment (low NaOH strength and insufficient alkali penetration) allowed for the presence of several antimicrobial compounds in brines, which inhibited the growth of Lactobacillus pentosus. These substances were the dialdehydic form of decarboxymethyl elenolic acid either free or linked to hydroxytyrosol and an isomer of oleoside 11-methyl ester. Olive brines, from olives treated with a NaOH solution of low concentration up to 1/2 the distance to the pit, contained these antimicrobials, and no lactic acid fermentation took place in them. By contrast, a more intense alkaline treatment (2/3 lye depth penetration) gave rise to an abundant growth of lactic acid bacteria without any antimicrobial in brines. Therefore, the precise cause of stuck fermentation in Manzanilla olive brines was demonstrated for the first time and this finding will contribute to better understand the table olive fermentation process.     

烷基苯SO3磺化工艺改进

在采用烷基苯SO3磺化工艺制造烷基苯磺酸过程中,许多装置会遇到含量、色泽不稳定的问题。通过对某合成洗涤剂厂烷基苯SO3磺化设备、工艺等因素的研究分析,对生产工艺进行了系统改进,烷基苯磺酸含量稳定在96%以上,色泽稳定在30klett以下。     

乳酸菌拮抗食源性致病菌研究进展

食品中致病菌是引起人类食源性疾病等食品安全问题主要因素之一。乳酸菌通过生态位竞争、形成酸性环境和产生各种代谢产物对食品中致病菌具有较强的拮抗作用。本文对乳酸菌生物保护剂的拮抗机制、作用的特点和优势,乳酸菌对各类食源性致病菌的拮抗作用研究以及在乳制品、肉制品、海产品和果蔬制品中的应用进行综述,为充分挖掘乳酸菌资源,利用乳酸菌生物保护剂控制食品中致病菌提供借鉴与参考。      

乳酸菌Lactobacillussp.strain2-3厌氧发酵蜂花粉的工艺优化

为提高蜂花粉的营养价值,将从蜂粮中分离获得的乳酸菌Lactobacillus sp.strain 2-3用于蜂花粉厌氧发酵,以活菌数、感官评分作为主要考察指标,在单因素基础上对蜂花粉厌氧发酵工艺进行优化,通过对正交实验的9个实验组的乳酸菌活菌数、感官评分、总黄酮、总酚、DPPH自由基清除率、甲酸、乳酸、乙酸、丙酸、丁酸、异丁酸、戊酸、异戊酸、还原糖等指标进行检测,对实验结果进行显著性分析和相关性分析,选取代表性指标活菌数、感官评分、异丁酸进行正交优化分析,确定乳酸菌厌氧发酵蜂花粉的最优工艺。结果表明,蜂花粉厌氧发酵的最优发酵工艺为:水分添加量50%、发酵温度37℃、乳酸菌接种量10%、发酵时间48 h,发酵蜂花粉活菌数可达54.90×10⁸cfu/g,感官评分为13.33,异丁酸含量3.60 mg/g。此外,总黄酮、总酚和DPPH自由基清除率相较于对照组分别提高了94.17%、83.75%、106.45%;挥发酸的种类更加丰富,产生了丁酸和异丁酸,总挥发酸含量也增加到167.80 mg/g;还原糖含量增至48.70%。结果表明蜂粮源乳酸菌可以应用于蜂花粉发酵,提高了蜂花粉营养价值。