含精油可食性抗菌膜研究进展

可食性抗菌膜是目前食品包装领域研究的重要方向,含精油可食性抗菌膜是其研究的热点之一。本文介绍含精油的可食性食品包装膜中精油的主要成分及其抗菌特性,概述此类膜的一般制备技术,对含精油膜抗菌的抗菌性能测试方法进行归纳,就精油对可食性膜抗氧化性、机械性能、渗透性及其他理化性能的影响作重点阐述,最后分析含精油可食性抗菌膜可能存在的问题,并预测其发展前景。     

植物精油在可食性抗菌膜中的应用

本文简要介绍了可食性抗菌膜的种类和抑菌机理,综述了近年来国内外植物精油的提取技术、化学成分、抑菌机理、植物精油对可食性抗菌膜性能的影响及其在食品保鲜上的应用的研究进展,并分析了植物精油应用在可食性抗菌膜上可能存在的问题,对其未来发展前景进行了展望。     

植物精油在可食性抗菌膜中的应用

本文简要介绍了可食性抗菌膜的种类和抑菌机理,综述了近年来国内外植物精油的提取技术、化学成分、抑菌机理、植物精油对可食性抗菌膜性能的影响及其在食品保鲜上的应用的研究进展,并分析了植物精油应用在可食性抗菌膜上可能存在的问题,对其未来发展前景进行了展望。      

丁香精油-壳聚糖复合可食性膜对生肉糜保鲜效果的影响

研究丁香精油-壳聚糖复合可食性膜对生肉糜冷藏期间感官品质和货架期的影响。测定生肉糜样品在（4±1）℃冷藏期间细菌总数、pH值、硫代巴比妥酸反应物值、高铁肌红蛋白含量以及感官品质随时间的变化情况。结果表明：添加丁香精油可提高壳聚糖可食性膜的抗菌和抗氧化活性。包裹丁香精油-壳聚糖复合可食性膜可有效抑制生肉糜菌落总数和高铁肌红蛋白含量的增加;同时还可抑制贮藏过程中的脂肪氧化,对感官品质具有良好的保持作用,在（4±1）℃条件下贮藏期可达10～12 d,明显提高了生肉糜贮藏过程中的品质和货架期。丁香精油-壳聚糖复合膜可作为可食性包装膜延长生肉糜冷藏期间的货架期。     

3种植物精油微胶囊抗菌膜在鱼丸保鲜中的应用

分别以香芹酚、百里香酚、牛至油为芯材,以β-环糊精为壁材,制备抗菌微胶囊,将制备的抗菌微胶囊分散到壳聚糖和聚乙烯醇混合的基底膜中,制备成含植物精油微胶囊的抗菌膜。研究制备的3种植物精油微胶囊抗菌膜的力学性能和抗菌性能,并以挥发性盐基氮、pH值和感官评分为指标,探索3种微胶囊抗菌膜对鱼丸的保鲜效果。结果表明,3种植物精油微胶囊抗菌膜都具有较好的抑菌性能,都能延长鱼丸的货架期,其中,香芹酚膜具有最佳抑菌效果。     

壳聚糖/柠檬草精油复合膜的制备及性能研究

以壳聚糖为主要成膜材料,添加适量的柠檬草精油,制备可食性复合膜,测定了柠檬草精油对膜的理化性质和抗菌性能的影响。红外光谱谱图说明柠檬草精油与壳聚糖基质间发生相互作用。扫描电镜结果表明两者共混成膜时柠檬草精油均匀分散。添加柠檬草精油,降低了复合膜的透明度,却能有效提高其抗拉强度、水蒸气阻隔性能和抗菌活性。      

壳聚糖/柠檬草精油复合膜的制备及性能研究

以壳聚糖为主要成膜材料,添加适量的柠檬草精油,制备可食性复合膜,测定了柠檬草精油对膜的理化性质和抗菌性能的影响.红外光谱谱图说明柠檬草精油与壳聚糖基质间发生相互作用.扫描电镜结果表明两者共混成膜时柠檬草精油均匀分散.添加柠檬草精油,降低了复合膜的透明度,却能有效提高其抗拉强度、水蒸气阻隔性能和抗菌活性.     

可食性壳聚糖包装膜的研究进展

可食性壳聚糖包装膜具有可食性、生物相容性、无毒无污染等优点,相比传统化学合成包装材料发展前景广阔,因此日益成为研究热点。综述单一可食性壳聚糖包装膜、可食性淀粉或明胶-壳聚糖复合膜及可食性复合型壳聚糖膜等方面的研究进展。     

壳聚糖荔枝木质精油可食膜的性能及在冷鲜鸡肉保鲜中的应用

为了解壳聚糖-荔枝木质精油可食膜在食品保鲜中的应用,在壳聚糖溶液中添加0%、2%、4%、6%、8%和10%的的荔枝木质精油（v/v,以壳聚糖溶液体积为基准）,配制壳聚糖-荔枝木质精油可食膜,通过比较复合可食膜的机械性能、阻隔性能、抑菌性及抗氧化能力,获得最佳荔枝木质精油添加量;并以该比例精油复合可食膜进行冷鲜鸡肉包裹保鲜实验,对比普通保鲜膜包裹保鲜,分析冷鲜鸡肉的感官指标及品质变化（pH、挥发性盐基氮（TVB-N）及菌落总数）。研究发现：随着精油添加比例的增加,复合可食膜的机械性能、阻隔性能、抑菌性能及抗氧化性能均有所提升,其中添加体积比8%的壳聚糖-荔枝木质精油可食膜各性能最佳,其膜厚度为0.044±0.0012 mm,水蒸气透过率（water vapor permeability,WVP）为0.499±0.019 g·mm/m²·h·KPa,膜拉伸强度为34.674±1.2 MPa,延伸性为53.92%±1.04%,DPPH清除率为32.51%±1.42%,ABTS清除率为35.74%±1.14%;以该比例进行冷鲜鸡肉保鲜实验,在7 d的保鲜期间,TVB-N及菌落总数变化得到有效抑制。结果表明：添加荔枝木质精油的壳聚糖复合可食膜包裹保鲜鸡肉与普通保鲜膜包裹相比,可有效延长冷鲜鸡肉的货架期,具有更好的保鲜效果。     

植物多酚-壳聚糖抑菌保鲜膜的研究进展

植物多酚作为一种天然抗菌剂,因具有良好的抗氧化和抗菌活性,在抗菌膜材料领域倍受关注。针对植物多酚-壳聚糖复合抗菌膜的研究现状,本文综述了以植物多酚为主要抑菌剂的壳聚糖保鲜膜的研究进展,并重点对植物多酚-壳聚糖抑菌保鲜膜的成膜方法、成膜机理、物理性能、抗氧化能力、抑菌性能及抑菌机理、食品应用等方面进行阐述。并对植物多酚-壳聚糖抑菌保鲜膜的研究前景进行讨论,为植物多酚-壳聚糖抑菌保鲜膜的进一步研究提供一些建议。     

Chitosan coatings enriched with essential oils: Effects on fungi involved in fruit decay and mechanisms of action

BackgroundPesticides have a negative impact on the health of consumers and on the environment, and as a consequence, the use of naturally occurring antimicrobial agents have become more popular to prevent food spoilage. An alternative is the use of chitosan, because of its antimicrobial, antioxidant activities and its capacity to form films having good mechanical properties. Chitosan has been used in the preparation of films and coatings for the preservation of different food products, and the addition of essential oils have been shown to be a good strategy to improve its antimicrobial activity in situ.Scope and approachThis review compiles information related to studies and research that employ chitosan as matrix for films, coatings and nanogels with essential oils extracted from plants, as antifungal agent. A special emphasis has been addressed to the effect exerted on the most pathogenic fungi for crops, also highlighting the mechanisms of action that researchers attribute to the composite, together with inhibition data.Key Findings and ConclusionEffective natural treatments, using chitosan-essential oils films or nano-emulsions, improve the preservation of fruit in terms of fungal decay. The effect is particularly dependent on the ability to release the antimicrobial compounds from the polymer matrix, the type of essential oils, the fungal species, and the incubation temperature. Several efforts are still required to understand in detail the mechanism of degradation of perishable food, how the chitosan-essential oils composites control or inhibit food decay, the effects on other pathogenic and non-pathogenic moulds as well as on the production of mycotoxins.     

Biocontrol of Salmonella Typhimurium in RTE foods with the virulent bacteriophage FO1-E2

Antimicrobial agents can be incorporated into edible films to provide microbiological stability, since films can be used as carriers of a variety of additives to extend product shelf life and reduce the risk of microbial growth on food surfaces. Addition of antimicrobial agents to edible films offers advantages such as the use of small antimicrobial concentrations and low diffusion rates. The aim of this study was to evaluate inhibition by vapor contact of Aspergillus niger and Penicillium digitatum by selected concentrations of Mexican oregano (Lippia berlandieri Schauer), cinnamon (Cinnamomum verum) or lemongrass (Cymbopogon citratus) essential oils (EOs) added to amaranth, chitosan, or starch edible films. Essential oils were characterized by gas chromatography-mass spectrometry (GC/MS) analysis. Amaranth, chitosan and starch edible films were formulated with essential oil concentrations of 0.00, 0.25, 0.50, 0.75, 1.00, 2.00, or 4.00%. Antifungal activity was evaluated by determining the mold radial growth on agar media inoculated with A. niger and P. digitatum after exposure to vapors arising from essential oils added to amaranth, chitosan or starch films using the inverted lid technique. The modified Gompertz model adequately described mold growth curves (mean coefficient of determination 0.991 ± 0.05). Chitosan films exhibited better antifungal effectiveness (inhibition of A. niger with 0.25% of Mexican oregano and cinnamon EO; inhibition of P. digitatum with 0.50% EOs) than amaranth films (2.00 and 4.00% of cinnamon and Mexican oregano EO were needed to inhibit the studied molds, respectively). For chitosan and amaranth films a significant increase (p<0.05) of lag phase was observed among film concentrations while a significant decrease (p<0.05) of maximum specific growth was determined. Chitosan edible films incorporating Mexican oregano or cinnamon essential oil could improve the quality of foods by the action of the volatile compounds on surface growth of molds.     

Fungal Inactivation by Mexican Oregano (Lippia berlandieri Schauer) Essential Oil Added to Amaranth,Chitosan, or Starch Edible Films

ABSTRACT: Edible films can incorporate antimicrobial agents to provide microbiological stability, since they can be used as carriers of a wide number of additives that can extend product shelf life and reduce the risk of pathogenic bacteria growth on food surfaces. Addition of antimicrobial agents to edible films offers advantages such as the use of low antimicrobial concentrations and low diffusion rates. The aim of this study was to evaluate inhibition of Aspergillus niger and Penicillium spp. by selected concentrations of Mexican oregano (Lippia berlandieri Schauer) essential oil added to amaranth, chitosan, or starch edible films. Oregano essential oil was characterized by gas chromatography-mass spectrometry (GC/MS) analysis. Amaranth, chitosan, and starch edible films were formulated with essential oil concentrations of 0%, 0.25%, 0.50%, 0.75%, 1%, 2%, and 4%. Mold radial growth was evaluated inoculating spores in 2 ways: edible films were placed over inoculated agar, Film/Inoculum mode (F/I), or the edible films were first placed in the agar and then films were inoculated, Inoculum/Film mode (I/F). The modified Gompertz model adequately described growth curves. There was no significant difference (P > 0.05) in growth parameters between the 2 modes of inoculation. Antifungal effectiveness of edible films was starch > chitosan > amaranth. In starch edible films, both studied molds were inhibited with 0.50% of essential oil. Edible films added with Mexican oregano essential oil could improve the quality of foods by controlling surface growth of molds.     

Antimicrobial edible films and coatings for fresh and minimally processed fruits and vegetables: a review

The use of edible films and coatings is an environmentally friendly technology that offers substantial advantages for shelf-life increase of many food products including fruits and vegetables. The development of new natural edible films and coatings with the addition of antimicrobial compounds to preserve fresh and minimally processed fruits and vegetables is a technological challenge for the industry and a very active research field worldwide. Antimicrobial agents have been successfully added to edible composite films and coatings based on polysaccharides or proteins such as starch, cellulose derivatives, chitosan, alginate, fruit puree, whey protein isolated, soy protein, egg albumen, wheat gluten, or sodium caseinate. This paper reviews the development of edible films and coatings with antimicrobial activity, typically through the incorporation of antimicrobial food additives as ingredients, the effect of these edible films on the control of target microorganisms, the influence of antimicrobial agents on mechanical and barrier properties of stand-alone edible films, and the effect of the application of antimicrobial edible coatings on the quality of fresh and fresh-cut fruits and vegetables.     

Effect of Chitosan Essential Oil Films on the Storage-Keeping Quality of Pork Meat Products

Edible films based on chitosan were prepared, with and without basil or thyme essential oils, with the aim of assessing their protective ability against lipid oxidation and their antimicrobial activity. Chitosan films had good oxygen-barrier properties, which were worsened by essential oil addition, especially when the film equilibrium moisture content increased. Due to the oxygen-barrier effect, all the films effectively protected pork fat from oxidation, in comparison to unprotected samples. In spite of the worsening of the oxygen-barrier properties, the films with essential oils were more effective than those of pure chitosan, which points to the chemical action of specific antioxidant compounds of the oils. Films were effective to control microbial growth in minced pork meat, although the incorporation of essential oils did not improve their antimicrobial activity. Throughout the storage, the films led to colour changes in minced pork meat associated with the conversion of myoglobin into metmyoglobin due to the reduction of the oxygen availability.     

Development of Edible Films and Coatings with Antimicrobial Activity

Over the last years, considerable research has been conducted to develop and apply edible films and coatings made from a variety of agricultural commodities and/or wastes of food product industrialization. Such biopolymers include polysaccharides, proteins, and their blends. These materials present the possibility of being carriers of different additives, such as antimicrobial, antioxidant, nutraceuticals, and flavorings agents. In particular, the use of edibles films and coatings containing antimicrobials has demonstrated to be a useful tool as a stress factor to protect foodstuff against spoilage flora and to decrease the risk of pathogen growth. The more commonly antimicrobials used are organic acids, chitosan, nisin, the lactoperoxidase system, and some plant extracts and their essential oils. For the selection of an antimicrobial, it must be considered the effectiveness against the target microorganism and also the possible interactions among the antimicrobial, the film-forming biopolymer, and other food components present. These interactions can modify the antimicrobial activity and the characteristics of the film being these key factors for the development of antimicrobial films and coatings. The main objective of this article is to review the bibliography of the last years concerning the main hydrocolloids and antimicrobials used for developing edible films and coatings, the methods used to evaluate the antimicrobial activity, the applications and the legislation concerning edible films and coatings. Also, the different strategies related to the modification of structural characteristics and the future trends in the development are discussed. The information update will help to improve the design, development, and application of edible films and coatings tending to increase the safety and quality of food products and to prepare for food legislation changes that might be necessary while identifying future trends concerning a better functionality of edible films thought as a stress factor for lengthening shelf life of food products.     

Antimicrobial Activity of Chitosan Films Enriched with Essential Oils

ABSTRACT: Antimicrobial and physicochemical properties of chitosan films and chitosan films enriched with essential oils (EO) were determined in vitro and on processed meat. Antimicrobial effects of pure EO of anise, basil, coriander, and oregano, and of chitosan-essential oil films against Listeria monocytogenes and Escheri-chia coli O157:H7 were determined by an agar diffusion test. The antibacterial effects of the EO were similar when applied alone or incorporated in the films. The intensity of antimicrobial efficacy was in the following order: oregano > > coriander > basil > anise. The chitosan films and chitosan-oregano EO films were applied on inoculated bologna samples and stored 5 d at 10 °C. Pure chitosan films reduced L. monocytogenes by 2 logs, whereas the films with 1% and 2% oregano EO decreased the numbers of L. monocytogenes by 3.6 to 4 logs and E. coli by 3 logs. Pure chitosan films were 89 μm thick, whereas addition of 1% and 2% oregano EO increased thickness to 220 and 318 μm, respectively. During application on bologna discs, the films absorbed moisture, resulting in the final thickness of 143, 242, and 333 μm, respectively. Addition of oregano essential oil into the chitosan films decreased water vapor permeability, puncture and tensile strength, but increased elasticity of the films. The films have the potential to be used as active biodegradable films with strong antimicrobial effects.     

Perspectives for chitosan based antimicrobial films in food applications

Recently, increasing attention has been paid to develop and test films with antimicrobial properties in order to improve food safety and shelf life. Active biomolecules such as chitosan and its derivatives have a significant role in food application area in view of recent outbreaks of contaminations associated with food products as well as growing concerns regarding the negative environmental impact of packaging materials currently in use. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, non-toxicity and versatile chemical and physical properties. Thus, chitosan based films have proven to be very effective in food preservation. The presence of amino group in C2 position of chitosan provides major functionality towards biotechnological needs, particularly, in food applications. Chitosan based polymeric materials can be formed into fibers, films, gels, sponges, beads or even nanoparticles. Chitosan films have shown potential to be used as a packaging material for the quality preservation of a variety of food. Besides, chitosan has widely been used in antimicrobial films to provide edible protective coating, in dipping and spraying for the food products due to its antimicrobial properties. Chitosan has exhibited high antimicrobial activity against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. The present review aims to highlight various preparative methods and antimicrobial activity including the mechanism of the antimicrobial action of chitosan based films. The optimisation of the biocidic properties of these so called biocomposites films and role of biocatalysts in improvement of quality and shelf life of foods has been discussed.