2株酸梅汤饮料污染霉菌的分离与鉴定研究

目的:对酸梅汤饮料中的污染霉菌进行分离与鉴定.方法:采用涂布分离法分离污染霉菌,经形态学观察和ITS区rDNA序列分析对菌株进行鉴定.结果:从产生絮状沉淀的酸梅汤饮料中分离到2株霉菌,经鉴定这两株污染菌分别为黄暗青霉(Penicillium citreonigrum)和光孢青霉(Penicillium glabrum).结论:根据两种污染菌的常见生境,酸梅汤饮料中的污染菌可能来自生产果汁的水果原料.     

鲜切苹果腐败霉菌的分离鉴定及致腐力的研究

对引起鲜切苹果腐败的霉菌进行分离鉴定并通过活体实验比较致腐能力。从鲜切苹果中分离13株霉菌,通过形态学鉴定方法分为5个属,其中青霉菌属(Penicillium)7株,曲霉属(Aspergillus)1株,枝孢属(Cladosporium)3株,枝顶孢属(Acremonium)1株,链格孢属(Alternaria)1株。根据青霉菌在CA、CYA、G25N培养基上的特征及镜检观察,将所分离的青霉菌鉴定为5种:皮落青霉(P.crustosum),扩展青霉(P.expansum),米舒青霉(P.miczynskii),橘灰青霉(P.aurantiogriseum),鲜绿青霉(P.viridicatum)。活体实验进行腐败与非腐败霉菌的分类,得到腐败霉菌有5种,分别为鲜绿青霉、扩展青霉、皮落青霉、互隔交链格孢霉(A.alternata)、黑曲霉(A.niger);非腐败霉菌有5种,分别为橘灰青霉、地生枝顶孢(A.terricola)、球孢枝孢(C.sphaerospermum)、枝状枝孢(C.cladosporioides)和米舒青霉。5种腐败霉菌的致腐能力从大到小依次为:皮落青霉、扩展青霉、鲜绿青霉、互隔交链格孢霉、黑曲霉。     

传统发酵食品-浆水中微生物的分离与初步鉴定

通过对浆水中的微生物进行分离培养及数量测定，查明了浆水中的优势菌为乳酸菌及酵母菌，其次尚有少量放线菌，霉菌为污染菌。从不同样品中分离得到了2株乳酸菌、3株酵母菌，1株放线菌及2株霉菌，通过对其形态、培养特征及生物学特性的研究，初步鉴定2株乳酸菌分属于乳杆菌属（Lactobacillus）和明串珠菌属（Leaconostoc）；3株酵母菌分属于酒香酵母属（Brettanomyces）、隐球酵母属（Cryptococcus）及裂殖酵母属（Schizosaccharomyces）；放线菌属于诺卡氏菌属（Nocardia）；2株霉菌分属于青霉属（Penicillium）和曲霉属（Aspergillus）。     

宋河酒曲中主要霉菌的鉴定及其产酶特性的研究

霉菌是酿酒大曲菌群的重要组成部分,其产酶能力影响大曲质量。对宋河中高温大曲和高温大曲中的霉菌进行分离纯化,采用形态学和18Sr DNA基因分析对主要霉菌进行鉴定,并采用透明圈法初筛主要产酶菌,半固态发酵测酶活法研究几株初筛霉菌的产酶功能。结果表明:共得到具有明显特征的10株霉菌,9株分别归属于4个属即为青霉属(Penicillium)、曲霉属(Aspergillus)、毛霉属(Mucor)和链格孢属(Alernaria),1株未确定;初筛得到7株均能产生淀粉酶、蛋白酶、纤维素酶和酯化酶的功能霉菌,其中菌株MM9产α-淀粉酶和蛋白酶的活力较高,其酶活分别为32.45U/m L和587.50U/m L,菌株Mh2产纤维素酶活力最高达11.87U/m L;菌株MM10产酯化酶活力最高为16.03U/m L。     

传统发酵豆酱中产脂肪酶菌株的筛选

脂肪酶属于羧基酯水解酶类,能将甘油三酯逐步地水解成甘油和脂肪酸。该研究从东北三省传统的家庭自制豆酱上获得纯培养真菌389株,通过三丁酸甘油酯平板法初筛获得具有脂肪酶活性的菌株41株,其中青霉属的真菌27株、曲霉5株、毛霉3株、犁头霉2株、酵母菌1株、镰孢菌2株、帚霉菌1株。结果表明,青霉属的真菌无论从数量还是酶活都高于其他属的真菌,其中橘灰青霉（Penicillium aurantiogriseum）数量最多。在分离到的菌株中,毛霉属的卷枝毛霉（Mucor circinelloides）酶活最高,是具有生物催化潜力的功能菌株。     

小曲中霉菌的分离纯化鉴定

小曲中的微生物主要有霉菌、酵母以及少量的细菌，在小曲上能看到的菌丝基本上都属于霉菌。以广东省九江酒厂有限公司提供的小曲为出发菌，采用土豆汁培养基进行纯培养，选取长有24个单菌落的平板进行分离纯化。制成纯培养菌。通过菌落特征、形态、制片标本和生理生化试验对纯培养菌进行鉴定。共分离出根霉菌株9株，经鉴定。其中根霉属4株。毛霉属1株，曲霉属3株。青霉属1株。(小雨)     

蜜环菌生长培养基的优化及杂菌的分离鉴定

为提高蜜环菌产量,采用正交试验法对蜜环菌生长培养基中葡萄糖、酵母粉、维生素B13个组分的添加量进行优化,利用平板法分离出影响蜜环菌生长的主要杂菌并采用分子生物学的方法对污染菌株进行鉴定。试验结果表明:葡萄糖45 g/L、酵母粉9 g/L、维生素B10.05 g/L为最佳配方。分离出两株霉菌,经过鉴定,分别为橘青霉Penicillium citrinum t1、塔宾黑曲霉Aspergillus tubingensis t2。     

肉桂醛的防霉效果及在月饼中的应用研究

市售月饼样品840份,在对其进行霉菌计数分析的基础上,对其优势霉菌进行了分离鉴定。从市售月饼中分离到常见霉菌主要有青霉属、曲霉属、毛霉、根霉、芽枝霉、镰刀菌等,其中优势霉菌为青霉属和曲霉属的霉菌,分别占分离总数的42%和37%。采用平板法测定了肉桂醛对分离到的6种霉菌的抗菌活性,结果表明其对青霉和曲霉的最小抑菌浓度分别为6mg/kg和12mg/kg。将染有10mg和20mg肉桂醛的纸片(2cm×2cm)和100g染有0.5ml青霉和曲霉菌混合孢子悬液(每毫升含有回收菌量约103个孢子)的月饼样品置于同一包装中,置28℃下培养观察,结果对照组试验第2d月饼就发生霉变,而试验组观察20d尚未发生霉变现象。     

鲜切生菜致腐霉菌的分离鉴定

对引起鲜切生菜腐败的霉菌进行分离鉴定。通过形态学鉴定方法,从鲜切生菜中分离出46株霉菌,其中青霉菌属(Penicillium)28株,曲霉属(Aspergillus)13株,枝孢属(Cladosporium)3株,镰孢属(Fusarium)2株。根据不同属在不同培养基上的性状,通过在察氏琼脂培养基(CA)、察氏酵母膏琼脂培养基(CYA)、查氏酵母浸出液加蔗糖培养基(CY20S)、25%甘油硝酸盐琼脂培养基(G25N)和玉米粉琼脂培养基(CMA)等鉴定培养基上的特征及显微镜观察,将28株青霉菌属鉴定为三种:橘灰青霉(P.aurantiogriseum)、鲜绿青霉(P.viridicatum)、草酸青霉(P.oxalicum)。13株曲霉属鉴定为两种:泡盛曲霉(A.awamori)、蜂蜜曲霉(A.melleus)。枝孢属鉴定为一种:枝孢样枝孢霉(C.cladosporioides)。     

酿酒葡萄中内生霉菌的分离与初步鉴定

采用组织块培养法,对新疆优质酿酒葡萄“赤霞珠”中的内生霉菌进行分离、纯化,共得到24株不同的内生霉菌,其中秋天得到的菌数最多,为11株,春天次之,为8株,夏天最少,为5株;从酿酒葡萄的根、茎、叶、果实部位均分离得到了内生真菌,分别为7、5、9和3株.通过对其中两株产多酚能力较强的内生霉菌C-2-J-6和C-1-G-3的形态鉴定,初步确定这两株菌分别属于星珠毒属和青霉属.     

不同加热处理对花生维生素含量的影响研究

以花生为原料,研究加热处理(水煮、蒸煮、油炸)对花生中维生素的影响.结果 表明:以湿基计,油炸处理后维生素E含量未发生显著变化,其他处理均使维生素E含量下降,花生中的烟酸在水煮处理之后保留率最低;以干基计,加热处理前后维生素E含量无显著变化,花生中的维生素B1在油炸处理之后保留率最低.不同加热处理后花生中烟酸、维生素B...     

Vitamin Fortification of Fluid Milk

Vitamin concentrates with vitamins A and D are used for fortification of fluid milk. Although many of the degradation components of vitamins A and D have an important role in flavor/fragrance applications, they may also be source(s) of off‐flavor(s) in vitamin fortified milk due to their heat, oxygen, and the light sensitivity. It is very important for the dairy industry to understand how vitamin concentrates can impact flavor and flavor stability of fluid milk. Currently, little research on vitamin degradation products can be found with respect to flavor contributions. In this review, the history, regulations, processing, and storage stability of vitamins in fluid milk are addressed along with some hypotheses for the role of vitamin A and D fortification on flavor and stability of fluid milk.     

维生素D缺乏对新生儿健康影响的研究进展

维生素D是一种脂溶性维生素,不仅具有抗菌抗炎、免疫调节的作用,还参与了人体多种细胞的增殖、分化、凋亡。维生素D缺乏已成为全球性的公共卫生问题,孕妇维生素D缺乏对母婴二人均有直接影响,是新生儿健康的危险因素之一。本文主要综述了维生素D的代谢及生理功能、影响新生儿维生素D水平的因素、维生素D缺乏与新生儿疾病的关系、维生素D水平评价标准、维生素Ｄ的推荐剂量及膳食补充。以期达到提高孕妇补充维生素D的意识的目的,为提高我国新生儿生存质量提供保障,同时为新生儿相关疾病的预防和治疗提供新思路。     

维生素B1、B2含量测定方法比较

目的:比较维生素B1、B2含量测定方法。方法:采用紫外分光光度法中三种不同方法测定维生素B1、B2含量。结果:1、按E值测标示量维生素B1:98.3±2.51,维生素B2:94.8±0.308,复合维生素B片中维生素B1:102.1±1.70,维生素B1平均回收率为100.4%,RSD为2.13%(n=6),维生素B2平均回收率为94.9%,RSD为6.5%(n=6)。2、标准曲线法维生素B1、B2浓度分别在3～18、1～8μg/ml范围内,均呈良好线性关系,标示量分别为:102.9±0.661,98.4±0.152。3、双波长法测维生素B1标示量:94.2±1.97。结论:三种方法用于维生素B1、B2含量测定,操作简便、快速、准确,精密度好。     

Dietary Intake of Natural Antioxidants: Vitamins and Polyphenols

Oxidative stress is a condition in which oxidant metabolites exert their toxic effect because of an increased production or an altered cellular mechanism of protection; oxidative stress is rapidly gaining recognition as a key phenomenon in chronic diseases. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. Endogenous defence mechanisms are inadequate for the complete prevention of oxidative damage, and different sources of dietary antioxidants may be especially important. This article calls attention to the dietary antioxidants, such as vitamins A, C, and E and polyphenols. Compelling evidence has led to the conclusion that diet is a key environmental factor and a potential tool for the control of chronic diseases. More specifically, fruits and vegetables have been shown to exert a protective effect. The high content of minerals and natural antioxidant as vitamins A, C, and E and polyphenols in fruits and vegetables may be a main factor responsible for these effects.     

Short communication: effect of vitamins E and C on cortisol production by bovine adrenocortical cells in vitro

The aim was to determine if vitamins E and C inhibit the release of cortisol from bovine adrenocortical cells when stimulated with ACTH in vitro. A factorial arrangement of treatments was used to culture bovine adrenocortical cells with different concentrations of vitamins E and C [(+)-α-tocopherol at 0, 2.3, and 16 μM and l-ascorbic acid at 0, 15, and 50 μM]. After 3 and 7 d of vitamin treatments, cell cultures were stimulated with ACTH (1 nM) for 24 h and the culture medium extracted to measure cortisol released by the cells using HPLC with UV detection. Vitamin E, vitamin C, or their combination did not affect the amount of cortisol released by the adrenal cultures to the media. Cortisol released by the adrenal cultures ranged from 33.6 ± 6.85 to 49.7 ± 8.01 nmol per 10⁷ cells. The modulation effect of vitamins E and C on the stress response does not take place at the cortex of the adrenal gland.     

柱切换法液相色谱测定保健食品中的VA、VD、VE

建立柱切换法液相色谱测定保健食品中VA、VD、VE含量的方法.参照GB 5009.82-2016《食品中维生素A、D、E的测定》样品前处理方法,以Agilent Poroshell 120 PFP(4.6 mm×100 mm,2.7 μm)为一维色谱柱,甲醇、水为流动相梯度洗脱,分离VA和VE的4种异构体,以Agile...     

How Safe is Vitamin E Supplementation?

The safety of large doses of vitamin E went virtually unquestioned until the early 2000s, when several studies were published showing that consumption of vitamin E from dietary supplements increased mortality, as well as the risk of gastrointestinal cancer and heart failure. These studies prompted numerous letters to the editors of medical journals and widespread coverage in the media. Both the medical community and the general public became confused and concerned about the use of vitamin E supplements. The purpose of this article is to review the medical literature and to explain these unusual findings. First we provide an overview of the earlier literature on vitamin E. Second, we provide a critical assessment of three meta-analyses that were neutral or negative toward vitamin E supplementation. Third, we review the limitations of meta-analyses in general. Fourth, we assess the individual studies that comprised one of the three meta-analyses. Since all three meta-analyses used many of the same studies, the individual critique should further the understanding of the limitations of these meta-analyses, and the meta-analysis approach in general. Lastly, we offer some guidance for healthcare professionals to give to the general, healthy public and those with chronic conditions who are no doubt left puzzled as to what to do regarding vitamin E supplementation.     

云南6种食用菌中维生素B1和B2的含量调查

目的 调查分析云南省6种食用菌中维生素B1和B2的含量。方法 定点采集云南省6种常见新鲜食用菌, 按GB 5009.84-2016《食品安全国家标准 食品中维生素B1的测定》和GB 5009.85-2016《食品安全国家标准 食品中维生素B2的测定》, 用高效液相色谱法测定样品中的维生素B1和B2的含量。结果 6种常见新鲜食用菌中维生素B1的含量平均值最高的是虎掌菌0.0812 mg/100 g, 最低的是干巴菌为0.0298 mg/100 g; 维生素B2含量平均值最高的是干巴菌为0.587 mg/100 g, 平均值最低的是人工种植的羊肚菌为0.0510 mg/100 g。 结论 人工种植和野生的食用菌均含有一定量的维生素B1和B2, 具有一定的营养价值。     

乳粉中主要B族维生素检测的GB和AOAC方法比较分析

为探究维生素B1、B2、B3（烟酸）、B6的国家标准方法和AOAC官方方法检测结果的可比性和误差来源,该研究通过对测试结果的F检验、显著性差异检验对维生素B1、B2、B3、B6的国家标准方法和AOAC官方方法进行了等效分析、并通过双向单侧t检验（TOST）对维生素B2进行了详尽的比较分析。分析结果表明,维生素B1、维生素B3和维生素B6国家标准方法和AOAC官方方法之间无显著性差异,而维生素B2国家标准方法和AOAC方法之间机理存在差异,通过等效性分析后数据结果表明两种方法等效不好;实验中发现在乳粉基质中添加酸性磷酸酶能够获得更接近可比性数据结果。