植物乳杆菌ST-Ⅲ在豆乳中的发酵特性及发酵豆乳的贮藏稳定性

通过测定植物乳杆菌ST-Ⅲ在发酵豆乳过程中的生长曲线、酸化曲线、蛋白水解能力和豆乳表观黏度、终产品感官分值,以及发酵豆乳在不同贮藏温度下植物乳杆菌ST-Ⅲ菌数、pH值、持水力和感官变化,研究植物乳杆菌ST-Ⅲ在豆乳中的发酵特性和发酵豆乳产品的贮藏稳定性。结果显示,植物乳杆菌ST-Ⅲ在豆乳中生长良好,到达发酵终点时的菌数为6.1×108 CFU/mL(对数值为8.78),表观黏度可达0.24Pa·s,感官品质较佳;发酵豆乳在低温(4℃)条件下各指标变化差异较小,贮藏稳定性明显优于常温(25℃)时。表明植物乳杆菌ST-Ⅲ具有发酵豆乳制品的优势与潜力。     

改善膨化米粉冲调性的实验报告

通过选择合适的大米原料，在膨化料中加入适宜的食品添加剂及控制膨化米粉的粗细度等方法，能够较好地改善膨化米粉的冲调性。     

Anti-listerial properties of garlic shoot juice at growth and morphology of Listeria monocytogenes

The anti-listerial effect of garlic shoot juice (GSJ) was investigated against the four strains of Listeria monocytogenes ATCC 19116, 19118, 19166 and 15313. Various concentrations of (1%, 2.5% and 5%) were used and applied for 0, 4, 7, 10 and 14 days at 4 °C and 0, 6, 12, 18 and 24 h at 37 °C. 5% GSJ showed the strongest anti-listerial effect of 3–4 log cfu/ml against all the bacterial strains tested as compared to control at 37 °C. At 4 °C, 2.5% GSJ showed a strong growth inhibitory effect of about 2–3 log cfu/ml against all the bacterial strains when compared to control after 14 days, and 5% GSJ rather decreased the number of bacterial cell when compared to initial polulation and showed general lysis of cytoplasm, lysis of cell wall and cellular swelling, and on scanning electron microscopy (SEM) observation, strain L. monocytogenes ATCC 19118 showed swelling, partially distorted shape, pore formation and empty cell formation inside the cell.     

DifferentLactobacillus helveticusstrain populations dominate during Grana Padano cheesemaking

Sixty-two strains ofLactobacillus helveticusisolated from whey starter cultures for Grana Padano cheese and from the cheese curd after moulding were grouped by PCR fingerprinting and SDS-;PAGE fingerprinting of cell wall proteins. Strain clustering allowed discrimination of five groups ofL. helveticusstrains, distributed differently between the whey starter and the cheese. In particular, two clearly distinguished biotypes respectively dominated theL. helveticuspopulations of the whey starter and the cheese curd after moulding. These two groups of strains also showed a peculiar cell wall protein profile, thus strengthening differences between biotypes alternatively dominating in whey starter and cheese curd. This study showed that the community ofL. helveticusdominating in Grana cheese is composed of different biotypes. Cheese technology parameters may play a major role in selecting dominant strains.     

食品企业供应商质量保证能力的现场审核

供应商质量保证能力的现场审核是供应商管理过程中的重要内容。从质量管理、基础设施、卫生和安全、过程控制、原料控制、检验能力等六个方面对食品企业供应商质量保证能力方面的现场审核进行了详细介绍。     

离子色谱法测定饮用水中的8种阴离子

利用MIC型离子色谱仪,对饮用水中F^-、Cl^-、NO2^-、NO3^-、P04^3-和SO4^2-阴离子进行检测。采用Supp5-4．0mm＊150mm离子色谱柱,3．2mol/L碳酸钠和1．0mol／L碳酸氢钠淋洗液,抑制型电导检测。结果表明,利用这个离子色谱的最佳条件可以对饮用水中的8种阴离子同时准确快速地定性定量检测。F^-、HCOO^-、Cl^-、NO2^-、Br^-、NO3^-、PO4^3-和SO4^2-的相对标准偏差为：1．588％-3．270％,检出限为：0．012mg／L-5．076mg／L,回收率为：94．0％～105．2％。实验结果发现有水样中的F含量超出国家标准。     

Study on processing and quality improvement of frozen noodles

The processing method and quality improvement of frozen noodles were studied. To obtain the best mouthfeel and control the breakage during processing and cooking, noodles with a thickness of 1.1 mm and width of 3.4 mm were produced. The precooking method for raw noodles was steaming for 10 min and then boiling for 4 min before freezing to obtain the optimal characteristics for frozen noodles. Five frequently used food additives (guar gum, sodium stearyl lactate (SSL), cassava starch, glucose oxidase (GOD), and α-amylase) were used to improve the quality of frozen noodles. Cooking losses and sensory evaluation scores were adopted to optimize the formulation of frozen dough by a response surface methodology (RSM): guar gum 0.28%, SSL 0.44%, cassava starch 4.82%, GOD 0.003%, and α-amylase 0.04%. Frozen noodles had a more continuous microstructure and their storage quality was improved notably by this method.     

Illumina MiSeq平台高覆盖率测定干酪中的细菌微生物多样性

采用第二代测序Illumina MiSeq方法测定了来自内蒙古4个不同地区的自然成熟干酪中的细菌微生物多样性。Iluumnia MiSeq方法可以快速有效地测定微生物的组成结构及其分布。分析了4种干酪样品中菌种类别和丰度分布、群落组成、不同样品间物种差异及进化关系等,全面的展现了干酪中细菌微生物的多样性分布。     

酸奶中长双歧杆菌PCR计数方法的建立

根据细菌保守序列设计一对通用引物,扩增细菌16S rDNA序列,作为阳性标记;根据长双歧杆菌菌株的16S rRNA和23S rRNA之间的间区基因序列设计定性PCR引物。用BBL琼脂平板对长双歧杆菌混合发酵的酸奶进行培养计数,随机挑选部分长出的菌落,提取DNA做PCR鉴定。将PCR技术与传统平板计数技术结合起来,初步建立酸奶中长双歧杆活菌计数方法。抽提方法操作简便、高效、灵敏,决定着PCR计数方法的准确高效,本研究着重研究了菌体DNA抽提方法的影响因素,以及抽提方法通用性,同时也研究了PCR引物的特异性。将PCR技术与传统平板计数技术结合起来,初步建立酸奶中长双歧杆活菌计数方法。      

乳清蛋白在无添加剂酸奶中的应用

本实验采用乳清蛋白制备了一种不添加稳定剂的酸奶,为制作无添加剂酸奶提供理论依据。通过分析不同添加量的乳清蛋白对酸奶发酵终点,以及后熟和保质期内酸奶的酸度、粘度、脱水收缩作用敏感性（STS）、持水率（WHC）的影响,结果发现：乳清蛋白对发酵终点的影响不大;随着乳清蛋白添加量的增加,在后熟时酸奶的酸度变化加快;乳清蛋白可以提高酸奶在保质期内的稳定性,对STS和WHC都有促进作用,可保证产品最终质量。此外,结合感官测评,乳清蛋白添加量在3~4%时,产品口感及稳定性较佳,通过使用乳清蛋白可以使无添加剂的酸奶在保质期内稳定。