高纯度难消化糊精的制备工艺及其特性研究

研究了高纯度难消化糊精的制备工艺及其特性。以玉米淀粉为原料,经过高温酸解得到焦糊精,再酶解、浓缩,采用酒精沉淀的方法得到难消化糊精后用酒精洗去葡萄糖,制备高纯度难消化糊精。结果表明最佳工艺条件为:加酸量为12%,焦糊化温度为180℃,焦糊化时间为0.5h,酒精洗涤次数为6次,此时高纯度难消化糊精得率可达40.32%,纯度可达95.30%。并测定了高纯度难消化糊精的分子量分布和热特性分析,重均分子量为8607u,热稳定性高。本文为其在各类食品中的应用奠定了一定基础。     

难消化糊精的研究进展

难消化糊精是抗消化、低热量的膳食纤维食品,具有降低血糖血脂、防止血糖升高、改善肠胃功能、促进体内益生菌增殖和预防疾病等生理功能,2012年被卫生部批准为普通食品。随着人们生活品质提高,越来越注重食品保健功能,难消化糊精的市场前景极其广阔。作者对难消化糊精的理化和结构特性、研究进展、生理功效、应用领域和产品市场概况进行总结分析,以期能促进难消化糊精行业的可持续健康发展。     

难消化糊精及其应用

介绍难消化糊精的性状、结构、生产工艺、质量标准以及使用安全性;阐述难消化糊精的生理功效及其在食品领域中应用。     

难消化糊精的研究进展

难消化糊精是抗消化、低热量的膳食纤维食品,具有降低血糖血脂、防止血糖升高、改善肠胃功能、促进体内益生菌增殖和预防疾病等生理功能,2012年被卫生部批准为普通食品。随着人们生活品质提高,越来越注重食品保健功能,难消化糊精的市场前景极其广阔。作者对难消化糊精的理化和结构特性、研究进展、生理功效、应用领域和产品市场概况进行总结分析,以期能促进难消化糊精行业的可持续健康发展。     

难消化糊精及其制备工艺

近年来膳食纤维的重要性得到了越来越多的关注,在许多国家除了糖、蛋白质、脂肪、维生素和矿物质外,膳食纤维被称为第六营养素。难消化糊精是以淀粉为原料制造的,是水溶性膳食纤维的一种。对难消化糊精的性状、结构、制备工艺以及影响产品质量的因素进行介绍。     

以淀粉为原料制造难消化糊精

本文介绍了以淀粉为原料制造难消化糊精的工艺过程。并对产品组成成分的影响因素一一作了阐述。     

由淀粉制备的食品添加剂─—低热量葡聚糖

由淀粉制备的食品添加剂─—低热量葡聚糖林勤保（华南理工大学轻工食品学院轻化所，广州，５１０６４１）食品与发酵工业１９９５年第３期低热量葡聚糖由于其中含有难消化成分，因而热量低，又称其为难消化糊精，是水溶性食物纤维的一种。在日本，低热量葡聚糖的产量在各...     

超高压对抗性糊精制备过程的影响

通过表征超高压条件(500 MPa, 10 min)对抗性糊精制备各阶段的结构及性质影响，探究难消化性更强的抗性糊精制备条件。结果表明，在高温(170℃, 2 h)、酸化(基于淀粉质量10%的盐酸)及超高压(500 MPa, 10 min)条件下，糊精化过程得到促进，结晶度降低的同时淀粉分子被水解成更小分子质量的短链糖和糊精片段。超高压在各阶段均促进酸热发挥作用，溶解度提升，达到80%左右，水分活度(AW)整体低于淀粉，影响食品稳定性的反应难以发生。键型结构方面，超高压处理后新形成的键型包括α-1,2、α-1,6、β-糖苷键、还原端等结构，新键型不利于再结晶和双螺旋结构的形成，故平均聚合度(DP)降低。高压与转苷酶联用对两者的转糖苷作用使得抗性糊精平均分支度(DB)大幅增加，远高于焦糊精，最高达到45.54%,此时难消化性最强。超高压助于α-淀粉酶淀粉分子解聚的基础上，也提供给了转苷酶更多的底物，间接增进酶反应效率。     

低血糖生成指数淀粉类衍生物的研究进展

本文综述了近年来低血糖生成指数淀粉类衍生物的研究进展,并简要介绍了国内外对血糖生成指数、低血糖生成指数食品的生理学功能及其淀粉类衍生物(如难消化糊精、慢消化淀粉、抗酶解淀粉、淀粉-脂质复合物、淀粉-蛋白质复合物等)方面的基本研究状况,展望了其发展前景.     

难消化糊精Fibersol2的保健功效

将淀粉以粉末的状态加热分解后调制而成的产品称之为焙烤糊精，其作为赋形剂或稀释剂在食品和医药品领域已得到广泛使用。早在20世纪50年代，人们就发现，在焙烤糊精中含有抗人体消化酶（如：淀粉酶、葡萄糖淀粉酶等）作用的成分。但应用这些成分对人体消化系统进行有针对性试验的事例一直未见有公开发表。直至近年，日本松谷化学工业株式会社开发出了难消化糊精Fibersol 2，其具有多种生理效果并取得日本政府特定保健食品原料的认定。截至2001年10月23日，日本厚生劳动省批准的252种特定保健食品中的32种使用了Fibersol 2，占总数的12.7%…     

贵州黔南地区泡制酸菜中酵母菌的分离与鉴定

采用纯培养的方法从贵州黔南地区20份自然发酵泡制酸菜中分离出115株酵母菌,通过WL培养基观察菌落特征,并结合显微细胞形态及生理生化特性,将115株酵母分为17种类型。从每种类型中挑选一株进行26S rDNA D1/D2区系列测定,通过序列分析及构建系统发育树,进行种属鉴定。结果表明：17类酵母共115株分属于11个属,其中30.43%为Kazachstania酵母、26.96%为毕赤酵母属(Pichia)、17.39%为地霉属(Geotrichum)、4.35%为假丝酵母属(Candida)、3.48%为耶罗威亚酵母属(Yarrowia)、3.48%为丝孢酵母属(Trichosporon)、3.48%为Meyerozyma酵母、2.61%为有孢汉逊酵母属(Hanseniaspora)、2.61%为Wickerhamomyces酵母、2.61%为Apiotrichum酵母、2.61%为棒孢酵母属(Clavispora)。     

Isolation and identification of nontuberculous mycobacteria from foods as possible exposure sources

A variety of foods collected from local supermarkets and produce stands were examined as possible sources of nontuberculous mycobacterial exposure. Food samples were combined with sterile ultrapure water and manually shaken. To remove large particles, the suspensions were filtered through a sterile strainer, centrifuged, and the supernatants were discarded. The food pellets were stored at -75 degrees C. The pellets were treated with either oxalic acid or sodium hydroxide-sodium citrate solutions to reduce contamination by nonmycobacterial organisms. Decontaminated pellets were cultured on both Middlebrook 7H10C agar and Middlebrook 7H10C agar with supplemental malachite green. Plates were observed for growth at 2 and 8 weeks. Isolates demonstrating acid-fastness were identified to species using polymerase chain reaction and restriction enzyme analysis. Nontuberculous mycobacteria (NTM) were recovered from 25 of 121 foods. Six different species of NTM were isolated, the most predominant being Mycobacterium avium.     

Outcome of clinical mastitis in dairy heifers assessed by reexamination of cases one month after treatment

Heifers that were treated for clinical mastitis prior to parturition or within 14 d postpartum were reexamined approximately 1 mo after treatment. Clinical examination of the heifers and microbiological examination of quarter milk samples were carried out on both occasions. Of the 1000 heifers included in the study, 10.9% were culled within 28 d after treatment. Udder damage caused by mastitis was the only or main reason for culling in 96% of those heifers. In comparison, 4.5% of nonmastitic heifers from the same herds were culled within 30 d postpartum. Twenty-five percent of those heifers that were not culled at d 28 after treatment had at least one nonfunctional quarter at that time. One thousand one hundred twenty-two quarters that were clinically affected at the time of treatment were reexamined; 22% were nonfunctional, 14% were still affected by clinical mastitis, 12% had subclinical mastitis, 5% had a latent infection with coagulase-positive staphylococci or Streptococcus dysgalactiae, and 46% were bacteriologically negative and had a normal cell count at the time of reexamination. High percentages of nonfunctional quarters were observed among those quarters that were infected with Arcanobacterium pyogenes or with coagulase-positive staphylococci at treatment. When all quarters that were clinically affected at treatment were considered, 40% of quarters were cured and were still in lactation at reexamination. Quarters infected with coagulase-negative staphylococci had a higher cure rate than quarters infected with other organisms. At reexamination, clinical signs of thelitis were observed in many of those quarters that were nonfunctional following the episode of clinical mastitis and also in 25% of lactating quarters in which clinical mastitis persisted.     

北京市市售带壳牡蛎致病性弧菌污染状况调查

目的了解北京市市售带壳牡蛎致病性弧菌污染状况。方法 2014年2~11月每月在某水产品批发市场的摊位抽样200只带壳牡蛎,共80份样品(其中腮和肠样品分别为40份)。用常规培养方法检测牡蛎腮和肠(含便)中致病性弧菌,对副溶血性弧菌进行血清学分型,荧光定量PCR检测副溶血性弧菌毒力基因tdh、trh和tlh。结果 80份牡蛎样品中,致病性弧菌阳性样品检出率为62.50%(50/80),副溶血性弧菌阳性菌株检出率为33.75%(27/80),溶藻弧菌阳性菌株检出率为31.25%(25/80);各牡蛎腮和肠样品中,致病性弧菌阳性检出率为67.50%(27/40)和57.50%(23/40);27株副溶血性弧菌共9种血清型;毒力基因检测结果表示,tlh均为阳性,tdh和trh均为阴性。结论北京市市售带壳牡蛎中致病性弧菌污染严重,以副溶血性弧菌和溶藻弧菌检出为主。     

Effects of Vacuum Packaging and Potassium Sorbate on Yield, Yeast and Mold Growth, and Quality of Dry-Cured Hams

Two trials were conducted. In the first trial hams were cured by a standard process and aged 1 month at 24°C. Group I hams were not packaged or treated. Group II hams were vacuum packaged and Group III hams were dipped in a 2.5% potassium sorbate solution and also vacuum packaged. All hams were examined after 1 month and the treated group was dipped in a 5% sorbate solution, vacuum packaged and aged an additional 2 months. Vacuum packaging practically eliminated further weight loss while potassium sorbate reduced but did not eliminate mold growth. In the second trial hams were again cured by a standard process and aged at 24°C until they were officially country hams (18% weight loss). Group I hams were not treated whereas group II hams were dipped in a 10% potassium sorbate solution. All were vacuum packaged. After aging one month they were unpacked, weighed, and examined for molds. No significant weight loss had occurred but mold counts were lower in the dipped group. The dipping procedure was reversed so that group I hams were treated and group II hams were not treated. All hams were again vacuum packaged and held a second month. No additional weight loss was noted. Mold growth, though not eliminated, was minimal, and visual and aroma scores for the cut hams were similar and highly acceptable. Tenderness, flavor, saltiness, and overall satisfaction scores for cooked slices were similar and highly acceptable. In general, mold growth can be greatly reduced by the use of potassium sorbate and weight loss can be controlled by vacuum packaging.     

水性聚氨酯涂饰剂的性能分析

对几种水性聚氨酯涂饰剂的性能进行了多方面的测定分析，包括聚氨酯涂饰剂的含固量和pH值、聚氨酯涂饰剂膜的感观和机械性能、聚氨酯涂饰剂运用于涂饰中时涂层的性能。通过测定分析了解了这些聚氨酯涂饰剂的优缺点，以及它们用于皮革涂饰工艺中时所适用的涂饰种类。     

基于UPLC-MS/MS的3 个李品种果实初生代谢物分析

以蜂糖李、空心李和脆红李果实为试材，采用超高效液相色谱-串联质谱技术对其初生代谢物进行定性和定量分析；并通过主成分分析、正交偏最小二乘判别分析和样本相关性分析等方法，比较各品种之间的差异代谢物，及通过京都基因与基因组百科全书富集分析，解析代谢通路之间的差异。结果表明：3 个李品种果实共检测到12 类307 种代谢物，主要包括氨基酸及其衍生物、核苷酸及其衍生物、有机酸、糖类、醇类、游离脂肪酸等代谢物。蜂糖李与脆红李之间的差异代谢物有70 种，其中43 种物质相对含量上调，27 种下调，分别占61.43%和38.57%；差异显著的代谢途径有5 条，分别是代谢通路、氨基酰-tRNA生物合成通路、缬氨酸、亮氨酸和异亮氨酸的生物合成通路、硫代葡萄糖苷的生物合成通路和赖氨酸降解通路。蜂糖李与空心李之间的差异代谢物有96 种，其中84 种物质上调和12 种物质下调，分别占87.50%和12.50%；差异显著的代谢途径有1 条为色氨酸代谢通路。空心李与脆红李之间共检测到75 种差异代谢物，其中19 种上调，56 种下调，分别占比为25.33%和74.67%；差异显著代谢途径有2 条分别是嘌呤代谢通路和硫代葡萄糖苷生物合成通路。     

江西省食源性沙门菌血清分型及脉冲场凝胶电泳指纹图谱研究

研究江西省食源性沙门菌的血清型,用脉冲场凝胶电泳(PFGE)方法对优势血清型进行分子分型,建立江西省食源性沙门菌PFGE指纹图谱资料库,为食源性疾病溯源提供数据。方法 对136株食源性沙门菌进行血清分型,对其中优势血清型德尔卑沙门菌菌株进行PFGE分型,获得分子分型指纹图谱,运用Bionumerics v6.6软件进行聚类分析。结果 136株沙门菌分离株血清群以B群为主,优势血清型主要是德尔卑沙门菌(49.26%),67株德尔卑沙门菌可分为41个型别的PFGE指纹图谱(相似值100%的为同一PFGE型别),主要集中在3个型别中。结论 江西省食源性沙门菌血清型分布呈多样性,优势血清型是德尔卑沙门菌,生肉制品是其主要的来源,同种血清型别的PFGE指纹图谱无相关性。     

新疆特色干酪中乳酸菌的分离鉴定

从新疆不同牧区采集工艺不同的干酪制品,对其中的乳酸菌进行分离纯化、生理生化性质试验和16S rRNA分析.结果表明,分离、纯化出的104株乳酸菌种,有82株为乳杆菌属(Lactobacillus),12株为肠球菌属(Enterococcus),10株为魏斯氏菌属(Weissella).利用16S rRNA序列同源分析和系统发育树分析对具有不同生理生化特性的代表菌株进行了分子鉴定,鉴定结果为TNM-2与干酪乳杆菌(Lactobacillus casei)、Y5-4与食窦魏斯氏菌(Weissella cibaria)、NS2-2与植物乳杆菌(Lactobacillus plantarum)的同源性达到100％,NM-2与瑞士乳杆菌(Lactobacillus helveticus)、Y1-1与马乳酒乳杆菌(Lactobacillus kefiranofaciens)、WG与耐久肠球菌(Enterococcus durans)的同源性达到99％.     

微生物酶制剂在食品工业中的应用与安全

综述了微生物来源的酶制剂在食品工业各领域中的应用以及酶制剂应用的安全标准和工业化生产的安全卫生管理，并对酶制剂在食品工业中的发展方向和安全问题进行了讨论。