多糖及改性多糖作为涂膜保鲜材料的研究进展

多糖及改性多糖作为一种安全、无毒和有效的涂膜保鲜材料近年来得到广泛的研究和应用。本文简要概述水溶性大豆多糖、壳聚糖、茁霉多糖、淀粉、魔芋多糖和纤维素等多糖及改性多糖作为涂膜保鲜材料在果蔬和禽蛋上的应用,探讨多糖及改性多糖涂膜保鲜的机理及涂膜方法,并对多糖及改性多糖涂膜作为保鲜材料的存在问题、发展方向和应用前景进行展望。     

5种食用菌多糖及复配多糖对RAW264.7细胞的免疫调节作用

探究银耳多糖、茯苓多糖、香菇多糖、猴头菇多糖和竹荪多糖5种食用菌多糖及其两两复配得到的10种复配多糖对小鼠巨噬细胞RAW264.7的免疫调节作用。将RAW264.7细胞分为正常对照组、阳性组和样品（不同浓度的银耳多糖、茯苓多糖、香菇多糖、猴头菇多糖和竹荪多糖及其10种复配多糖）处理组,通过检测巨噬细胞的细胞活力、肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）分泌水平以及吞噬能力评价免疫调节作用。结果表明：与正常对照组相比,在质量浓度5 μg/mL～320 μg/mL范围内,5种食用菌多糖在一定浓度时皆能表现出显著增强巨噬细胞RAW264.7的细胞活力,提高巨噬细胞的吞噬能力,促进细胞因子TNF-α的分泌效果（P<0.05）。此外,10种复配多糖在RAW264.7细胞的细胞活力、TNF-α分泌和吞噬能力皆呈现出显著的促进效果。10种复配多糖中,基于香菇多糖和猴头菇多糖的复配多糖在浓度为160 μg/mL时促进细胞因子TNF-α的分泌效果最好;基于茯苓多糖和香菇多糖复配得到的复配多糖对细胞吞噬功能的增强效果最佳,且优于其组成多糖单独作用效果。基于银耳多糖和竹荪多糖复配得到的复配多糖在浓度为80 μg/mL时促进RAW264.7分泌TNF-α的效果优于其组成多糖单独作用,在浓度为160 μg/mL时对细胞吞噬功能的增强效果优于其组成多糖。银耳、茯苓、香菇、猴头菇、竹荪来源的多糖单独作用及其两两复配得到的复配多糖对RAW264.7细胞均具有免疫调节活性。不同多糖间可能存在相互作用,复配后免疫调节活性优于单独作用时免疫调节活性,例如茯苓多糖和香菇多糖,银耳多糖和竹荪多糖。     

不同食用菌多糖复配物对RAW264.7巨噬细胞的免疫调节作用

目的:探究5种食用菌多糖,包括银耳多糖（Tremella fuciformis polysaccharide）、茯苓多糖（Poriacocos polysaccharide）、香菇多糖（Lentinan）、猴头菇多糖（Hericium edodes polysaccharide）和竹荪多糖（Dictyophora indusiata polysaccharide）任意3种多糖复配得到的多糖复配物的免疫调节活性。方法:以RAW264.7巨噬细胞为研究对象,采用CCK-8试剂盒检测不同浓度的复配物对巨噬细胞增殖的影响,酶联免疫吸附法测定复配物处理后细胞培养液中肿瘤坏死因子-α（tumor necrosis factor-α, TNF-α）水平,以及流式细胞仪分析复配物处理后细胞吞噬能力。结果:与正常对照组相比,除了浓度为320 μg/mL的茯苓多糖、香菇多糖和竹荪多糖的多糖复配物,茯苓多糖、猴头菇多糖和竹荪多糖的多糖复配物以及香菇多糖、猴头菇多糖和竹荪多糖的多糖复配物外,在检测浓度范围内10种多糖复配物可明显促进巨噬细胞的增殖,增强吞噬能力,提高细胞因子TNF-α的分泌量。其中,10 μg/mL的银耳多糖、茯苓多糖和竹荪多糖的复配物促进巨噬细胞增殖的效果最佳,160 μg/mL的银耳多糖、茯苓多糖和香菇多糖的复配物能最好的促进TNF-α的分泌和增强RAW264.7的吞噬能力。结论:不同食用菌多糖的复配物均可调节巨噬细胞RAW264.7的免疫活性。本结果可为开发免疫调节功能的食用菌复配多糖产品提供数据参考。     

库拉索芦荟花多糖的分离纯化与组成分析

采用热水提取、酒精沉淀、Sevag法去蛋白、有机溶剂脱水的方法提取库拉索芦荟花粗多糖,DEAE SephadexA-25阴离子交换层析法从粗多糖中分离出中性多糖、弱酸性多糖和强酸性多糖.其中弱酸性多糖含量最高,约占多糖的87%,这不同于库拉索凝胶多糖,凝胶多糖主要由中性多糖组成,占总多糖的95%以上.进一步采用Sepharose4B凝胶过滤层析分级分离,测出单一多糖的分子量,并用气相色谱法测定出多糖的中性单糖组成.     

大豆多糖与纳豆多糖结构特征和主要生物活性比较

采用水提醇沉方法制备大豆和纳豆粗多糖样品,解析大豆多糖和纳豆多糖的化学组成及结构特征,研究大豆多糖和纳豆多糖的溶水能力、持水能力和脂肪结合能力,比较分析大豆多糖和纳豆多糖的体外抗氧化、降血糖和降血脂生物活性。结果表明：纳豆多糖中糖醛酸含量显著高于大豆多糖(P<0.05);大豆多糖和纳豆多糖的分子质量分别为5.256、33.532 ku,说明大豆多糖和纳豆多糖的单糖组成种类相似但比例不同;大豆多糖的表面粗糙,纳豆多糖表面光滑致密;纳豆多糖的溶水能力是大豆多糖的2.04倍,而大豆多糖的脂肪结合能力是纳豆多糖的2.99倍;纳豆多糖对1,1-二苯基-2-三硝基苯肼自由基的清除能力和2,2’-联氨-双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力的半抑制质量浓度(half maximal inhibitory concentration,IC₅₀)分别为(0.049±0.015)、(2.640±0.072)mg/mL,表现出更佳的抗氧化活性;纳豆多糖抑制α-淀粉酶活性的IC₅₀为(3.297±0.395)mg/m L,体外降血糖活性显著高于...     

葛根多糖的体外抗氧化活性研究

目的考察葛根多糖的体外抗氧化作用。方法从葛根中提取多糖,苯酚-硫酸法测定多糖含量。分别研究葛根粗多糖和精制多糖对DPPH、O_2~-·、·OH和NO_2-的清除作用,并与阳性对照VC进行比较,考察葛根多糖的抗氧化效果。结果葛根粗多糖中多糖含量为3.67%,精制多糖中多糖含量为8.74%。在0.5~4.0mg/mL浓度范围内,葛根粗多糖和精制多糖对DPPH、O_2~-·、·OH和NO_2~-均有不同程度的清除作用,清除活性顺序为·OHO_2~-·NO_2~-DPPH,且清除效果与多糖浓度呈剂量-效应关系,但清除率均低于阳性对照VC。在清除自由基时,相同浓度的葛根粗多糖的清除能力强于精制多糖。结论葛根多糖具有良好的抗氧化活性,可开发成新型的葛根源保健品或天然绿色的食品抗氧化剂。     

蒲公英不同器官多糖含量测定及抗氧化性研究

用热水浸提法提取蒲公英多糖,用苯酚-硫酸法测定不同器官多糖含量,结果显示:根、叶、花中多糖含量分别为56.02%、16.50%、36.74%.3种器官多糖对自由基都有一定的清除作用.根多糖清除自由基的作用不是很显著.叶多糖和花多糖对O2-·的清除作用很显著,分别达到96.9%和96.6%,花多糖对·OH的清除作用要好一些,最大为70.3%.3种器官多糖对LPO的清除作用都较低,最大值只有29.73%.实验说明蒲公英叶多糖和花多糖具有很好的抗氧化性.     

湘玉竹多糖的体外抗氧化活性研究

目的探索湘玉竹多糖的体外抗氧化效果。方法从湘玉竹中超声提取多糖,苯酚-硫酸法测定多糖含量。分别研究湘玉竹粗多糖和精制多糖对DPPH、O_2~-·、·OH和NO_2~-的清除作用,并与VC阳性对照进行比较,考察湘玉竹多糖的抗氧化效果。结果湘玉竹粗多糖中多糖含量为6.05%,精制多糖中多糖含量为13.26%。在试验浓度范围内,湘玉竹粗多糖和精制多糖对DPPH、O_2~-·、·OH和NO_2~-均有一定的清除作用,且清除效果与多糖浓度呈剂量-效应关系。IC_(50)结果显示湘玉竹多糖清除活性为O_2~-·DPPHNO_2~-·OH,而且相同浓度的湘玉竹粗多糖的清除能力强于精制多糖。除了NO_2~-以外,阳性对照VC对DPPH、O_2~-·和·OH自由基的清除能力均强于湘玉竹多糖。结论湘玉竹多糖具有良好的抗氧化能力,可开发成一种新的天然绿色食品抗氧化剂。     

假芝菌丝体多糖ARP的纯化、结构及抗氧化活性

以贵州册亨县的野生假芝(Amauroderma rugosum)为材料,分离菌丝体后液体发酵,采用水煮醇沉方法提取粗多糖,进一步脱蛋白、脱色、柱层析纯化后,得到精制多糖(ARP),采用多种色谱手段对多糖结构进行表征,测定、比较了粗多糖和精制多糖的体外抗氧化活性。结果表明:菌丝体精制多糖分子量为1. 86×10~4Da,红外和核磁显示有明显多糖特征峰,该多糖由鼠李糖、甘露糖和半乳糖组成,单糖摩尔比组成为1∶1. 24∶3. 51;从菌丝体提取的多糖抗氧化活性良好,粗多糖的抗氧化活性优于精制多糖,在质量浓度为1 mg/mL时,粗多糖的总还原力是精制多糖的1. 72倍;对DPPH·和ABTS·清除率良好,粗多糖对应EC50值是0. 05和0. 15 mg/mL;精制多糖是1. 15和1. 49 mg/mL。研究结果为假芝多糖的开发利用提供了科学依据。     

6种活性多糖的结构、性质及其抗氧化活性的比较研究

为研究多糖的结构和性质对其抗氧化活性的影响,从真菌多糖和藻类多糖中共选出6种多糖,分别为地木耳多糖、葛仙米多糖、发菜多糖、螺旋藻多糖、香菇多糖和茯苓多糖。对6种多糖进行分离纯化,共得到8种均一性多糖组分。分别对纯化后多糖的特性黏度、分子量、红外光谱、单糖组成、三股螺旋结构等相关参数进行测定,进一步对比纯化多糖的体外抗氧化能力,并利用最小偏二乘分析（partial least squares,PLS）初步分析纯化后多糖的结构、性质对其体外抗氧化活性的影响。结果表明：多糖溶液特性黏度与分子量大小有关,香菇多糖对DPPH自由基的清除作用、ABTS+自由基的清除能力和还原能力最强,单糖组成（葡萄糖醛酸、半乳糖和葡萄糖）和分子量对多糖体外抗氧化生物活性影响较大。     

小龙虾加工和流通过程中的食品安全与品质控制技术研究进展

小龙虾的加工和贮运流通是小龙虾全产业链中的重要环节之一,小龙虾质量安全与品质控制关系到百姓食品安全保障、风味和营养需求以及企业经济效益等,需要重点关注。本文根据原料及加工工艺、风味、贮运、消费要求及售卖产品特点不同,重点对小龙虾生鲜产品、半成品冻品、成品冻品和即食小龙虾在加工和流通过程中的食品安全与品质控制技术研究现状进行综述,并对小龙虾加工和流通过程中的风险分析、质量控制与标准化、信息化和智能化研究与实践应用情况进行总结,对未来发展趋势进行初步展望,旨在为促进小龙虾产业健康发展提供参考。     

2017~2019年日照市市售海带中铅、镉、汞、砷、无机砷污染监测分析

目的 调查日照市市售海带中常见污染物铅、镉、汞、砷、无机砷污染的含量,为市售海带的深加工与安全风险评价提供基础资料与科学依据。方法 在市直、县区各农贸市场、超市、食堂等进行随机采样,用电感耦合等离子体质谱仪(ICP-MS)测定市售海带中铅、镉、汞、砷的含量,以液相色谱-原子荧光光谱仪测定无机砷的含量,并按照湿、淡干、盐干等三种海带样品进行分类,对检测结果进行比较分析。 结果 2017～2019年日照市市售海带样品按照湿、淡干、盐干分类,三类样品中铅、镉、汞、砷及无机砷的含量在不同年度之间具有一致性。在同一年度中,铅、镉、砷含量的平均值：湿<盐干<淡干；汞含量平均值：湿<盐干、淡干,盐干、淡干样品中汞含量无显著差异；湿样品无机砷含量均合格,而淡干、盐干样品合格率偏低。结论 海带中铅、镉、汞、砷、无机砷污染普遍存在,而在湿、淡干与盐干海带中铅、镉、汞、砷、无机砷含量的差别应在监管与安全风险评估中给予重视。     

Red meat,diseases, and healthy alternatives: A critical review

Meat is an important food for human nutrition, by especially providing high-quality protein and also some essential micronutrients, in front iron, zinc, and vitamin B₁₂. However, a high intake of red and processed meat is associated with an increased risk for diseases, especially type 2 diabetes and colorectal cancer, as several epidemiological studies and meta-analyses have shown. This review summarizes meta-analyses of publications studying the association between red and processed meat intake and type 2 diabetes, cardiovascular diseases, colorectal and other cancers, and all-cause mortality. Various potential mechanisms involved in the increased disease risk are discussed. Furthermore, the beneficial effects of healthy alternatives for meat, like fish, nuts, vegetables and fruits, pulses and legumes, whole grains, and dairy products are reviewed by including selected papers and recent meta-analyses.     

饲喂磺胺间甲氧嘧啶对肉鸡肌肉中蛋白质、脂肪和矿物质的影响

探讨饲喂磺胺间甲氧嘧啶对鸡体质量以及鸡肉中水分、蛋白质、脂肪和矿物质元素含量变化的影响规律。本实验通过对160 只健康大骨鸡进行磺胺间甲氧嘧啶对照（仅饲喂基础日粮）、低、中、高剂量（0、25、200、500 mg/（kg·d））连续7 d给药,停药后16 d内采6 次样,取样前对鸡进行称质量,并检测鸡肉中水分、蛋白质、脂肪和矿物质元素（铁、铜、镁、锌和钙）的含量。结果表明：停药后16 d内,低剂量组鸡体质量显著增加,蛋白质和镁元素的含量升高;中剂量组鸡体内水分、脂肪和钙元素含量显著升高,铁元素含量显著降低;高剂量组鸡体质量增加缓慢且显著低于对照组,鸡肉中蛋白质、脂肪和铁元素的含量均显著降低。     

Applications of emerging imaging techniques for meat quality and safety detection and evaluation: A review

With improvement in people's living standards, many people nowadays pay more attention to quality and safety of meat. However, traditional methods for meat quality and safety detection and evaluation, such as manual inspection, mechanical methods, and chemical methods, are tedious, time-consuming, and destructive, which cannot meet the requirements of modern meat industry. Therefore, seeking out rapid, non-destructive, and accurate inspection techniques is important for the meat industry. In recent years, a number of novel and noninvasive imaging techniques, such as optical imaging, ultrasound imaging, tomographic imaging, thermal imaging, and odor imaging, have emerged and shown great potential in quality and safety assessment. In this paper, a detailed overview of advanced applications of these emerging imaging techniques for quality and safety assessment of different types of meat (pork, beef, lamb, chicken, and fish) is presented. In addition, advantages and disadvantages of each imaging technique are also summarized. Finally, future trends for these emerging imaging techniques are discussed, including integration of multiple imaging techniques, cost reduction, and developing powerful image-processing algorithms.     

MEASUREMENT OF CARBOHYDRATES IN WORT AND BEER—A REVIEW

Methods are reviewed for measuring total wort and beer carbohydrate and carbohydrate fractions, such as dextrins, oligosaccharides, fermentable sugars, β-glucans, total fructose and fructosans, pentose and pentosans. The methods are conveniently classified under the following headings: reductometry, colorimetry, enzymic procedures, automated analyses, paper and column chromatography, thin layer chromatography, gas liquid chromatography and high performance liquid chromatography. Techniques involving chromatography are particularly useful for separating and estimating individual sugars.     

Sensory characteristics of dudh churpi in relation to its chemical composition

 Dudh churpi, a traditional milk product, had more moisture, fat, water-dispersible protein (WDP), titratable acid, energy, lactic acid, free fatty acids (FFA), 2-thiobarbituric acid (TBA) and tyrosine contents and also reflectance, but less sensory attributes, when prepared in Darjeeling than the products prepared in Sikkim and Bhutan. Sensory attributes were positively correlated with total solids, protein, lactose, sugar, hydroxymethylfurfural (HMF) and p-dimethylaminobenzaldehyde reactivity, and negatively correlated with fat, FFA, TBA, WDP, tyrosine, lactic acid and titratable acidity. Whereas total solids, fat, protein, lactose, glucose-galactose and total sugar accounted for 71% of the flavour score, 64% of the body and texture score, 77% of the colour and appearance score and 77% of the total score, lactic acid, FFA, TBA, tyrosine and HMF jointly reflected variations of 61%, 50%, 81% and 67% in flavour, body and texture, colour and appearance, and total score, respectively. Received: 6 July 1998     

采前喷施壳聚糖复合膜对猕猴桃软腐病的防控及其保鲜作用

以‘贵长’猕猴桃为试材,通过病原菌分离、致病性测定和DNA测序鉴定了修文县猕猴桃软腐病病原菌,并选用壳聚糖、钙盐和糊精分别与茶多酚、甘氨酸、柠檬酸、抗菌肽混合制备和筛选了复合膜剂,研究了采前幼果期和壮果末期果面喷施壳聚糖复合膜对猕猴桃软腐病的防控及其保鲜作用。结果表明,修文县猕猴桃软腐病病原菌为葡萄座腔菌（Botryosphaeria dothidea）和拟茎点霉菌（Phomopsis sp.）;采前喷施不同壳聚糖复合膜对其软腐病的防效均达60%以上（添加茶多酚防效86.54%、甘氨酸防效61.54%、柠檬酸防效71.15%、抗菌肽防效69.23%）,显著降低丙二醛（MDA）积累,提高果实的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性,诱导增强果实的抗病性。同时,该复合膜能有效地增加果实单果质量和体积,显著提高果实VC、可溶性固形物、可溶性总糖、可滴定酸、叶绿素和蛋白质的含量,促进猕猴桃产量的增加和品质的改善。此外,施用该复合膜还能有效提高和维持果实硬度、降低果实呼吸强度以及果实质量损失率和营养物质的损失,明显抑制果实可溶性固形物和可溶性总糖含量的上升速率和延缓组织的衰老软化,从而提高了猕猴桃耐贮性。研究结果为猕猴桃优质栽培、病害有机防控和果实绿色保鲜提供了科学依据和新途径。     

水煮加工对3 种海产贝类中重金属元素形态的影响

采用电感耦合等离子体质谱和原子荧光形态检测法分析宁海、象山、舟山3 个养殖区内常见3 种海产贝类（牡蛎、缢蛏、血蚶）中Cd、Cu、Cr、Pb、As、Hg等重金属的总含量,并采用化学逐级提取法系统研究水煮加工前后贝类中Cd、Cu、Cr、Pb重金属的形态分布和As、Hg中有机和无机的形态分布。结果表明,3 个养殖区牡蛎、缢蛏、血蚶中Cd、Cr、Cu、Pb、As均有不同程度的超标,且Cu和Cd、Cr和Pb之间存在显著相关性,As的超标检出率达77.78%,Hg的残留量均低于限量标准;此外金属形态分析研究结果表明,水煮加工方式对Cd、Cu、Cr、Pb中酸可提取态、氧化结合态、有机结合态和残余态的含量影响较大,而对As和Hg的有机态和无机态影响较小。海洋贝类中重金属元素的含量和水煮加工前后该元素形态的变化量可作为评价海洋贝类中重金属生物有效性的指标。     

New Material as New Media: The Fabric Workshop and Museum Marion Boulton Stroud

Abstract

This article investigates the relationship between people and their things when the consumer or owner is also, potentially, the maker. By analyzing the ways in which people construct personal narratives and/or identities through the construction of specific items intended for themselves or others, this article aims to uncover intimate forms of object relations. Knitting is a relatively simple activity and is frequently done by hand. Stigmatized as old-fashioned, ugly, thrifty, domestic, and inherently feminine, both knitting and the objects resulting from its practice seemingly occupy a space that is neither craft nor design, yet the practice of knitting remains widespread and its objects, coveted, loved, accepted, rejected, and so on, as any object would be. Knitting has historically been associated with both familial and romantic love: of time spent thinking of someone whilst making, with the made object an expression of the sacrifice of time, of thoughtfulness, and the embodiment of feminine “virtues” of caring and nurturing. Equally, one can see the knitted object, when it is a garment or a toy, as close to the body, touching and being touched by the body, further extending its potential for intimacy. Yet, the communication of these values are only recognized if the object is received and used as the maker intended, and this article aims to highlight, through example, the ways in which such objects do not solely represent “love,” but also signify possessiveness, control, and domination. Referencing literature, magazine articles, objects, and makers’ testimony, this article utilizes a design history and material culture methodology, which enables the discussion of both object and practice, as well as creating a model from which the object's biography can be evaluated.