明胶-壳聚糖抗菌膜中啤酒花提取物的释放行为

制备以啤酒花提取物为抗菌剂的明胶-壳聚糖抗菌膜,研究抗菌剂在食品模拟液中的释放行为。分别探讨了不同释放环境温度对啤酒花浸膏、α-酸和β-酸在体积分数10%、50%和95%乙醇溶液中释放行为的影响。结果表明:抗菌剂的释放量随着时间的延长和温度的升高而逐渐增大,直至达到平衡。在不同食品模拟液中,食品模拟液的水分体积分数越高,抗菌剂的释放量越小。在相同条件下,啤酒花浸膏的释放最为缓慢,且达到平衡时的释放量最小。拟合Peleg模型,所得方程相关系数R2均大于0.98,说明拟合具有一定的可靠性,Peleg模型可以预测啤酒花浸膏、α-酸和β-酸在食品模拟液中的释放行为。     

纳米银-聚乙烯复合包装中银对2 种抗氧化剂向食品模拟物迁移的影响

探究纳米银-聚乙烯复合包装中纳米银成分的存在对2 种抗氧化剂（Irganox1076和Irgafos168）向食品模拟物迁移规律的影响。将含有抗氧化剂的聚乙烯包装膜和同时含有抗氧化剂与纳米银的复合包装膜裁成正方形若干,分别浸泡于正己烷和体积分数95%乙醇溶液2 种食品模拟物中,密封后在20、40 ℃以及70 ℃条件下进行迁移实验。食品模拟物中2 种抗氧化剂的加标回收率在79.3%～108.0%之间,相对标准偏差在0.7%～5.3%之间。2 种抗氧化剂的迁移会随着迁移温度的升高以及迁移时间的延长而增加直至达到迁移平衡,且其在正己烷模拟物中的迁移量大于在体积分数95%乙醇模拟物中的迁移量;含纳米银聚乙烯塑料比不含纳米银聚乙烯塑料中的抗氧化剂向食品模拟物中的迁移量小,表明纳米银成分的存在可以抑制包装中的抗氧化剂向食品模拟物中的迁移。     

壳聚糖-PE双层抑菌保鲜膜的结构和热稳定性

采用流延法将壳聚糖成膜液涂覆在PE保鲜膜的表面制备壳聚糖-PE双层抑菌保鲜膜。分析壳聚糖-PE双层膜的结构和热稳定性,以期观测双层膜中有无新的化学键形成以及壳聚糖膜是否与PE膜形成一定的界面结合,通过红外光谱和扫描电子显微镜分析双层膜的结构,采用热重分析法和示差扫描量热法分析双层膜的热稳定性。结果表明,壳聚糖涂膜层与PE膜结合时未形成新的化学键,PE膜结构也未受到壳聚糖涂膜的影响,壳聚糖膜与PE膜之间形成了良好的界面结合。     

壳聚糖/微晶甾醇可食性复合膜的制备、性能及结构表征

以壳聚糖为成膜基质,添加具有抗氧化和抑菌作用的植物甾醇,采用流延法制备壳聚糖/微晶甾醇可食性复合膜,旨在赋予壳聚糖膜抗氧化活性及提高其抑菌性。当甾醇添加量分别为壳聚糖质量的0%~12%时,随着添加比例的增加,复合膜的拉伸强度和断裂伸长率逐渐下降,溶解度和溶胀度逐渐增加,水蒸气透过系数显著降低,对超氧阴离子自由基(O_2~-·)及羟自由基(·OH)的清除率显著提高,对金黄色葡萄球菌和大肠杆菌的抑菌性能明显增强;采用红外光谱、扫描电子显微镜、X射线衍射和热重分析表征了复合膜的相容性。结果表明:甾醇添加量为9%的壳聚糖/微晶甾醇可食性复合膜各项性能指标良好,且壳聚糖与甾醇分子之间形成了分子间氢键,有较强的相互作用,整个共混体系的相容性良好。     

对羟基苯甲酸壳聚糖酯合成工艺优化及生物活性评价

本文将常用防腐剂对羟基苯甲酸(p-hydroxybenzoic acid,PA)接枝到壳聚糖(chitosan,CS)上，以改善其应用性能。在惰性气氛下，采用单因素实验以及响应面设计法研究其合成反应条件，并考察其体外抗氧化和抑菌性能。在单因素实验的基础上，通过响应面设计法得到对羟基苯甲酸壳聚糖酯(PA-g-CS)的最佳制备工艺是：PA与CS摩尔质量比为1∶1,Vc添加量为0.20 g,H₂O₂添加量为1.00 g，反应时间为12.0 h。在此条件下，PA-g-CS的接枝量为101.16 mg PA/g，试验结果与模型预测结果相差仅1.64%。体外抗氧化和抑菌实验表明，与CS相比，PA-g-CS的ABTS⁺自由基清除活性和抑菌性能均显著增强，且PA-g-CS的接枝量越高，其抑菌活性越强。该工艺对于PA-g-CS的抗氧化和抑菌性能有明显的优化，PA-g-CS有望应用于活性包装、抗氧化剂和防腐剂等领域。     

抗微生物食品包装

过去 ,食品包装材料仅具有阻隔和保护功能 ,然而现在可在包装材料中添加各种活性物质来提高其功能性并赋予其新的功能。这种活性包装技术可延长食品的货架期 ,同时保持食品的营养价值和安全性。活性包装技术涉及到食品、包装材料与内部气体的相互作用(Ｌａｂｕｚａ和Ｂｒｅｅｎｅ ,1998) ,它能提供许多新的功能包括除氧 ,抗菌 ,除湿 ,除乙烯 ,释放乙醇等。本文重点介绍抗微生物食品包装体系。1　抗微生物食品包装在聚合物中添加抗微生物试剂 ,能限制或阻碍微生物生长 ,这点可有效地以膜或容器的形式用于食品。表 1总结了一些抗微生物包装体…     

咖啡酸接枝壳聚糖复合膜对薏仁米贮藏品质的影响

以壳聚糖(CS)为原料经咖啡酸改性制备咖啡酸接枝壳聚糖(CA-g-CS)复合膜，并与聚乙烯(PE)膜、CS膜对比，研究CA-g-CS复合膜对薏仁米保鲜效果的影响。结果表明：与PE膜和CS膜相比，CA-g-CS复合膜的水蒸气渗透率和抗拉强度更优，分别为3.55×10^-8 g·mm·h^-1·cm^-2·Pa^-1和20.74 MPa;与PE膜相比，CA-g-CS复合膜包装的薏米仁在贮藏4个月后，其脂肪酸值、过氧化值和丙二醛含量分别降低了31.04%、18.18%、27.63%;CA-g-CS复合膜包装的薏仁米在贮藏期间微生物数量低于PE膜和CS膜，且CA-g-CS复合膜包装的薏仁米中脂肪酸组成及相对含量与新鲜薏仁米近似。表明CA-g-CS复合膜有利于减缓薏仁米贮藏期间脂质氧化。     

壳聚糖-六氢-β-酸可食性抑菌膜的制备及抑菌剂的释放

以膜的机械性能（抗拉强度和断裂伸长率）为指标,采用单因素和正交试验优化壳聚糖-六氢-β-酸可食性抑菌膜的制备工艺,进而考察抑菌剂六氢-β-酸在95%、75%和55%乙醇溶液中的释放规律。结果表明,壳聚糖质量浓度对膜的机械性能影响最大,壳聚糖质量浓度和甘油体积分数的交互作用次之,干燥温度的影响最小。在壳聚糖质量浓度1.75 g/100 mL、干燥温度40 ℃、甘油体积分数1.4%优化条件下,制备的壳聚糖-六氢-β-酸可食性抑菌膜的机械性能最好,其抗拉强度为29.26 MPa,断裂伸长率为81.29%。释放实验表明,六氢-β-酸的释放随着时间的延长和温度的升高而逐渐增大,直至达到平衡。根据Peppas和Peleg方程得出六氢-β-酸在95%乙醇溶液中的释放过程为Fick扩散,而75%和55%乙醇溶液中符合Peleg方程。扩散系数随着温度的升高而逐渐增大,且在55%乙醇溶液中最为明显,说明释放溶剂中含水量和温度是影响六氢-β-酸扩散的重要因素。     

超临界溶液浸渍法制备丁香酚-壳聚糖食品活性包装膜

采用超临界溶液浸渍（supercritical solution impregnation,SSI）技术将丁香酚（eugenol,EG）负载于壳聚糖膜（chitosan film,CSF）中,制备用于食品活性包装的抑菌材料,分析SSI过程参数对丁香酚负载量的影响,并对EG-CSF的形貌、吸水量、水蒸气透过率和抑菌性能进行了考察。结果表明,EG-CSF的负载量随着浸渍压力的升高而增大,随着泄压速度的升高而降低,在压力20 MPa、泄压速率1 MPa/min时负载量达到最大,为6.02%。壳聚糖膜经SSI过程负载丁香酚后,吸水率和水蒸气透过率均下降。EG-CSF对金黄色葡萄球菌、绿脓假单胞菌、大肠杆菌均有较好的抑制作用,在食品活性包装领域具有应用潜力。     

壳聚糖-肉桂醛复合抗菌降解膜的制备及性能

为改善壳聚糖膜的抗菌效果,将肉桂醛添加到壳聚糖基膜中制成壳聚糖-肉桂醛复合膜,研究肉桂醛体积分数对复合膜的物理性质、力学性能、水蒸气透过系数、官能团结构、结晶程度、微观结构以及抗菌性能的影响。结果表明：随着肉桂醛体积分数的增加,复合膜的色差、水蒸气透过系数和断裂伸长率减小,膜的厚度显著增加;当肉桂醛体积分数为2%时,膜的抗拉强度最大,为（15.77±1.13）MPa;根据傅里叶变换红外光谱分析,壳聚糖与肉桂醛有较好的相容性;肉桂醛体积分数的增加会导致膜表面结晶程度、裂纹、粗糙程度增加;复合膜的抑菌性能也随着肉桂醛体积分数的增大而显著增大。该研究可为壳聚糖-肉桂醛复合降解膜的应用提供理论依据。     

食品包装PE材料中荧光增白剂迁移规律的分析

以PE塑料薄膜为研究对象,采用高效液相色谱法研究食品包装塑料材料中荧光增白剂在纯水、乙酸、乙醇、植物油4?种不同模拟物中的迁移规律,研究荧光增白剂溶出量与食品接触介质、乙酸质量浓度、乙醇体积分数、浸泡温度以及处理时间等因素的关系。结果表明：纯水基质食品模拟物对香豆素类荧光增白剂有一定溶解性,酸性食品模拟物相比于水模拟物有更强的溶解性,而含醇类食品模拟物和脂肪类食品模拟物对大部分荧光增白剂都具有较好的溶解效果;荧光增白剂的溶出量随着乙酸和乙醇含量的增加而增加;较高的温度对塑料包装材料中荧光增白剂的迁移溶出具有显著影响,并且随着接触时间的延长,塑料包装材料中的荧光增白剂向食品中迁移的可能性也不断增大。     

Development and evaluation of a novel biodegradable film made from chitosan and cinnamon essential oil with low affinity toward water

Combining antimicrobial agents such as plant essential oils directly into a food packaging is a form of active packaging. In this work chitosan-based films containing cinnamon essential oil (CEO) at level of 0.4%, .0.8%, and 1.5% and 2% (v/v) were prepared to examine their antibacterial, physical and mechanical properties. Scanning electron microscopy was carried out to explain structure–property relationships. Incorporating CEO into chitosan-based films increased antimicrobial activity. CEO decreased moisture content, solubility in water, water vapour permeability and elongation at break of chitosan films. It is postulated that the unique properties of the CEO added films could suggest the cross-linking effect of CEO components within the chitosan matrix. Electron microscopy images confirmed the results obtained in this study.     

Physicochemical, nutritional, and antimicrobial properties of wine grape (cv. Merlot) pomace extract-based films

Abstract: Wine grape pomace (WGP) (cv. Merlot) extract‐based films were studied in terms of their physicochemical, mechanical, water barrier, nutritional, and antibacterial properties. Pomace extract (PE) was obtained by hot water extraction and had a total soluble solid of 3.6% and pH 3.65. Plant‐based polysaccharides, low methoxyl pectin (LMP, 0.75% w/w), sodium alginate (SA, 0.3% w/w), or Ticafilm^® (TF, 2% w/w), was added into PE for film formation, respectively. Elongation at break and tensile strength were 23% and 4.04 MPa for TF‐PE film, 25% and 1.12 MPa for SA‐PE film, and 9.89% and 1.56 MPa for LMP‐PE film. Water vapor permeability of LMP‐PE and SA‐PE films was 63 and 60 g mm m^?2 d^?1 kPa, respectively, lower than that of TF‐PE film (70 g mm m^?2 d^?1 kPa) (P < 0.05). LMP‐PE film had higher water solubility, indicated by the haze percentage of water after 24 h of film immersion (52.8%) than that of TF‐PE (25.7%) and SA‐PE (15.9%) films, and also had higher amount of released phenolics (96.6%) than that of TF‐PE (93.8%) and SA‐PE (80.5%) films. PE films showed antibacterial activity against both Escherichia coli and Listeria innocua, in which approximate 5‐log reductions in E. coli and 1.7‐ to 3.0‐log reductions in L. innocua were observed at the end of 24 h incubation test compared with control. This study demonstrated the possibility of utilizing WGP extracts as natural, antimicrobial, and antioxidant promoting film‐forming material for various food applications. Practical Application: WGP extract‐based edible films with the addition of a small amount of commercial polysaccharides showed attractive color and comparable mechanical and water barrier properties to other edible films. The films also demonstrated their potential antioxidant and antimicrobial functions. Hence, they may be used as colorful wraps or coatings for food, pharmaceutical, or other similar applications.     

Mono- and multilayer active films containing lysozyme as antimicrobial agent

Active packaging materials able to release antimicrobial compounds into foodstuff can be used in order to avoid or slow down the bacterial growth during storage. In this work the use of two techniques to control the release of the chosen active compound (lysozyme) from a polymeric material into the foodstuff is proposed: a monolayer cross-linked PVOH film and a multilayer structure made of cross-linked PVOH layers are developed and studied. Lysozyme release tests into water were performed in order to compare the release kinetics from the investigated films. Results suggest that by means of both structures it is possible to control the rate at which lysozyme is released from the PVOH film. The antimicrobial activity of lysozyme released from the investigated films was tested against a suspension of Micrococcus lysodeikticus. Results show that the incorporation of lysozyme into PVOH does not lead to a loss of activity of the enzyme.

Industrial relevance

The increased use of gently processed foods requires packaging to be an integral part of the preservation concept. Consequently additional antimicrobial activity from the packaging material can aid in shelf life extension.This paper concentrates on the release rate of lysozyme, a naturally occuring antimicrobial agent (eg. salvia, mothers milk, raw milk), from multilayer films. A comperision of mono- and multilayer films containing lysozyme regarding their effectiveness on M. lysodeikticus as target organism was also performed. Both aims were met leading to a controlled release of lysozyme with no loss of activity.     

檀香叶提取物抗氧化及抗菌活性初步研究

研究檀香(Sandalwood)叶不同溶剂提取物的抗氧化及抗菌活性,为檀香叶资源开发利用提供依据。采用4种不同溶剂提取檀香叶中抗氧化、抗菌活性成分;采用清除DPPH自由基方法测定抗氧化活性,采用平板打孔法测定抗菌活性。结果表明:檀香叶80%乙醇、水、乙酸乙酯提取物可以清除DPPH自由基;80%乙醇提取物对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌有抗菌作用,但对霉菌、啤酒酵母没有抑菌作用。乙醇提取物经不同温度、不同光照时间处理后,其抗氧化、抗菌活性较稳定。乙醇提取物经不同pH处理后,抗氧化物质在pH6～8范围内稳定,抗菌物质在pH3～7范围内稳定,碱性条件下不稳定。檀香叶乙醇提取物化学成分标识结果表明:檀香叶乙醇提取物中含有多糖、鞣质、黄酮类、酚类物、有机酸以及氨基酸、多肽、蛋白质等成分。结论:80%乙醇、水、乙酸乙酯提取物具有抗氧化活性,其中,80%乙醇提取物抗氧化活性最好。只有80%乙醇提取物具有抗菌活性。     

Nisin as a Food Preservative: Part 2: Antimicrobial Polymer Materials Containing Nisin

Nisin is the only bacteriocin approved as a food preservative because of its antibacterial effectiveness and its negligible toxicity for humans. Typical problems encountered when nisin is directly added to foods are mainly fat adsorption leading to activity loss, heterogeneous distribution in the food matrix, inactivation by proteolytic enzymes, and emergence of resistance in normally sensitive bacteria strains. To overcome these problems, nisin can be immobilized in solid matrices that must act as diffusional barriers and allow controlling its release rate. This strategy allows maintaining a just sufficient nisin concentration at the food surface. The design of such antimicrobial materials must consider both bacterial growth kinetics but also nisin release kinetics. In this review, nisin incorporation in polymer-based materials will be discussed and special emphasis will be on the applications and properties of antimicrobial food packaging containing this bacteriocin.     

蛋壳膜酶解肽对大豆蛋白包装膜抑菌、抗氧化性能的影响

蛋白膜具有良好的机械性能,是一种环境友好的可食性包装材料,但其抑菌、抗氧化性能等包装活性较差,限制其在某些易腐食品包装领域的广泛应用.本研究以大豆分离蛋白(soy protein isolate,SPI)为成膜基质,加入不同添加量的蛋壳膜(eggshell membrane,ESM)酶解肽制备复合膜,以机械性能、阻隔性...     

Active chitosan–polyvinyl alcohol films with natural extracts

Active films were prepared from chitosan (Ch) and polyvinyl alcohol (PVA) containing aqueous mint extract (ME)/pomegranate peel extract (PE). The effect of these extracts on the physical, mechanical, antimicrobial and antioxidant properties of the films were studied. Increased protection against UV light was observed in the films containing the extracts. Addition of ME/PE improved the tensile strength of the films without affecting their puncture strength. Ch–PVA films incorporated with PE had the highest tensile strength (41.07 ± 0.88 MPa). Permeability characteristics of the films were not altered due to addition of extracts. ME/PE conferred antioxidant properties to Ch–PVA films as determined by DPPH radical scavenging activity. The films also exhibited antibacterial activity against Staphylococcus aureus and Bacillus cereus. PE containing films totally inhibited the growth of B. cereus and reduced the number of S. aureus by 2 log cycles. These results suggest that Ch–PVA film containing ME/PE can be used for development of active food packaging materials.     

肉桂精油-玉米淀粉基抗菌膜的制备及其性能

为研究新型抗菌降解包装材料,筛选肉桂精油等4?种植物精油,以玉米淀粉、壳聚糖和魔芋葡甘露聚糖为成膜基质,甘油为增塑剂,吐温-80为表面活性剂,研究肉桂精油添加对复合膜机械性能、光学性能、阻水性能和抑菌性能的影响。结果表明：4?种精油对金黄色葡萄球菌、大肠杆菌和沙门菌的抗菌活性依次为肉桂精油＞牛至精油＞百里香精油＞迷迭香精油。随着肉桂精油质量浓度增加,复合膜的抗拉强度和水蒸气透过系数降低,断裂伸长率和不透明度升高。当肉桂精油质量浓度在15.0～20.0?g/L时,复合膜色泽指数a*值无明显差异（P＞0.05）,L*值显著降低,b*值和ΔE值显著增加（P＜0.05）。添加肉桂精油显著提高了玉米淀粉基膜的抗菌能力（P＜0.05）,精油与吐温-80相互作用对革兰氏阴性的大肠杆菌具有协同作用,而对革兰氏阳性的金黄色葡萄球菌具有拮抗作用。当肉桂精油质量浓度为20.0?g/L时,膜具有较好的物理性能和抗菌效果。本研究可为肉桂精油-玉米淀粉基可降解抗菌膜生产工艺参数的进一步优化提供参考。