酵母β-葡聚糖牛奶增强免疫力功能研究

研究酵母β-葡聚糖牛奶增强免疫力功能.采用B1/Fq代健康雌性小鼠,设0.08,0.17,0.50g/kg 3个剂量组(分别相当于人体推荐摄入量的5倍、10倍、30倍),以纯牛奶配制,低、中、高剂量组质量浓度分别为8.0,17.0,50.0 g/L,经口每日1次给予小鼠相应浓度的受试样品,连续给样1个月,检测对小鼠体重...     

风味酶水解乳清蛋白生产蛋白胨的工艺条件

为了提高原料乳清蛋白(Whey Protein Concentrate,WPC)的产品附加值,利用风味蛋白酶对WPC进行水解,生产蛋白胨产品。结果表明:最优工艺条件为E/S(18 000 U/100 mL),温度为55℃,pH值6.0,水解时间为4.0 h,底物质量分数为8%,水解度为46.4%。利用此工艺生产的蛋白胨产品在理化指标、氨基酸组成及质量分数上均要好于市售的同类产品。     

利用16S rDNA序列及tuf-RFLP鉴定蒙古国发酵乳中的乳酸菌

运用16S rDNA序列分析和tuf-RFLP技术对采于蒙古国扎布汗省的25份发酵乳样中分离出的110株乳酸菌进行鉴定。首先将分离的110株乳酸菌的16S rRNA基因进行扩增,测序并构建系统发育树,初步鉴定为41株嗜热链球菌,40株瑞士乳杆菌,11株德氏乳杆菌保加利亚亚种,2株发酵乳杆菌,1株乳明串珠菌,2株肠膜明串肠膜亚种,1株乳酸乳球乳酸亚种和12株属于干酪族的菌株。由于干酪乳杆菌族的16S rDNA序列差异很小,故采用tuf-RFLP技术对这12株进行了进一步的验证,通过分离菌株与模式菌株tuf-RFLP图谱的比较分析,结果表明这12株菌均为干酪乳杆菌。     

利用响应面法优化重制干酪的制作工艺

以契达干酪为原料,采用响应面法对重制干酪的制作工艺进行优化。优化后乳化盐的使用量分别为:焦磷酸钠2%,柠檬酸钠1.5%,三聚磷酸钠2%,重制干酪的凝胶强度为528.1 g/cm2,感官评分4.8分。     

益生乳酸菌Lactobacillus casei Zhang从基础研究到产业化开发

2001年-2009年,内蒙古农业大学乳品生物技术与工程教育部重点实验室从采集自中国西部7个省市及蒙古国14个省市不同少数民族地区951份自然发酵乳制品等样品中分离鉴定出3 388株乳酸菌,建立了中国首个原创性乳酸菌菌种资源库;从菌种库中分离自传统发酵酸马奶(koumiss)的243株乳杆菌中筛选获得1株性能优良的乳酸菌—Lactobacillus casei Zhang(L.casei Zhang)。采用5种动物模型和人体试验进行了功能评价,并利用基因组学和蛋白质组学研究技术对L.casei Zhang益生分子机制进行了深入剖析。经过多年系统的基础研究,自主解决了其产业化的关键技术问题,包括其直投式发酵剂、发酵乳制品和发酵豆乳益生菌饮料的研发并实现了产业化。     

Garden cress oil as a vegan source of PUFA: Achieving through optimized supercritical carbon dioxide extraction

With more people shifting to healthier and environment-friendly lifestyles, the vegan diet has recently gained popularity. Nevertheless, this kind of diet comes with its own limitations in terms of adequate availability of nutrients, for example, essential fatty acids. The primary source for these includes fish and other marine animals, hence not accepted by the vegan population. The plant source is limited. The present work focuses on exploring garden cress (GC) seed oil - an easily available seed, with considerable polyunsaturated fatty acids (PUFA). Conventionally, Soxhlet extraction of vegetable oils is done using solvents like hexane. However, selective extraction of PUFA, phytosterols, and tocopherols could be done by supercritical-CO₂ (SC-CO₂) extraction of oil from the GC seeds with proper optimization of extraction parameters. The PUFA content was found to be 38% in the case of oil extracted with n-hexane. This was enriched to nearly 50% PUFA, when extracted at 350 bar pressure, 60 °C temperature, and 30 g/min flow rate in case of SC-CO₂ extraction. At similar conditions, even tocopherol contents were improved significantly from 486 to 1138 ppm. Further, oil enriched with unsaponifiable matter (2.3%) containing major phytosterols like campesterol, stigmasterol, β-sitosterol, and isofucosterol was obtained at 20 g/min flow rate itself. Another major advantage of SC-CO₂ extraction is the selective extraction of oil from the seed, leaving behind the phospholipids. This in turn eliminates one step of refining, thereby making the process economically viable. The use of co-solvents resulted in nutritionally enriched GC seed oil at a pressure of 250 bar. It is quite evident from the findings of this study that, careful selection of process parameters of SC-CO₂ extraction of GC seed oil can result in a nutritionally enriched vegan source of PUFA, using an emerging cleaner and greener technology.Industrial relevanceThere is a huge demand for newer vegan sources of PUFA. GC seed oil can be one of them. This investigation aimed at process development for extracting PUFA and tocopherol, phytosterol enriched GC oil using eco-friendly SC-CO₂ extraction. SC-CO₂ extraction is becoming more popular and the economic feasibility is proven for the higher scale of operation. As this oil can be encapsulated and sold at a reasonably good price, this work has significant industrial relevance.     

基于模糊数学的羊肉感官综合评价方法

选择相同饲养条件下相同月龄的巴美肉羊、小尾寒羊、苏尼特羊的股二头肌为感官评价对象,运用改进后的模糊综合评价方法对该批肉样感官质量进行评定。同时利用色差计和嫩度仪对肉样的色泽和嫩度剪切值进行测定,进一步验证评判结果的准确性。结果表明,在处理模糊程度较高的感官综合评价问题时,改进后的模糊评价方法具有较高的准确性。     

提高燕麦方便面品质的工艺研究

燕麦是一种杂粮作物,被认为是兼备食疗功能的优质谷物,具有极高的营养价值。以燕麦粉为主原料,配合小麦粉,制作燕麦方便面,研究添加玉米淀粉、沙蒿胶、谷朊粉及羧甲基纤维素钠(CMC-Na)对燕麦方便面品质的影响。试验结果表明,复合使用以上4种添加剂对改善燕麦方便面的品质具有显著作用。在和面过程中加入生面质量10.0%的玉米淀粉、2.0%沙蒿胶、0.3%CMC-Na、5.0%谷朊粉时效果最佳;在此工艺条件下燕麦方便面的糊化度为96.67%,复水率为2.21,断条率为0,感官评分47.9,综合值166.67。     

Effects of high hydrostatic pressure on the structure and retrogradation inhibition of oat starch

As a non-thermal processing technology, high hydrostatic pressure (HHP) can be used for starch modification without affecting the quality and flavour constituents. The effect of HHP on starch is closely related to the treatment pressure of HHP. In this paper, we investigated the impacts of HHP treatment pressure (0, 100, 200, 300, 400, 500, 600 MPa) on the microstructure and retrogradation characteristics of oat starch, established the retrogradation kinetic model and elaborated the mechanism of HHP treatment inhibiting the retrogradation of oat starch. Results show that HHP treatment caused the microstructure of oat starch experienced crystallisation perfection (100–300 MPa), crystallisation destruction (400 MPa), crystallisation disintegration and gelatinisation (500–600 MPa). Results of oat starch retrogradation showed that, after treated at 500 MPa for 15 min, the recrystallisation rate of oat starch was reduced, the formation of nuclei at the early stage of oat starch retrogradation suppressed and its nucleation mode was changed from instantaneous to spontaneous, otherwise, the mobility of water in oat starch gel system reduced. Therefore, 500 MPa treated for 15 min can inhibits the retrogradation of oat starch. This study provides theoretical guidance for the application of HHP technology in starch modification and food processing.     

Development of a non-target metabolomics-based screening method for elucidating metabolic and probiotic potential of bifidobacteria

Traditional in vitro screening assays for identifying probiotics often fail to provide a metabolomic overview of candidate strains. Thus, this work aimed to develop a non-target metabolomics-based method for screening bifidobacteria from a broad perspective. First, methods for extracting intracellular metabolites of bifidobacteria were compared. Methanol extraction with bead mill and sonication was selected as it yielded the highest metabolome signal intensity and coverage. Multivariate analyses revealed obvious differences in the intracellular metabolome between species/strains. Fourteen differential metabolites that have previously been reported to possess probiotic function were identified. Bifidobacterium animalis subsp. lactis Probio-M8 (M8) had significantly more intracellular lactose than other species/strains but showed lower cell density and viable counts in stationary phase. Adding lactose in the culture medium significantly enhanced the growth of M8 strain but not other tested bifidobacteria. This work provided a new screening method and practical data for selecting potential candidates for further validation.