Applications of chitosan for improvement of quality and shelf life of foods: a review

ABSTRACT:  Chitosan is a modified, natural biopolymer derived by deacetylation of chitin, a major component of the shells of crustacean. Recently, chitosan has received increased attention for its commercial applications in the biomedical, food, and chemical industries. Use of chitosan in food industry is readily seen due to its several distinctive biological activities and functional properties. The antimicrobial activity and film-forming property of chitosan make it a potential source of food preservative or coating material of natural origin. This review focuses on the applications of chitosan for improvement of quality and shelf life of various foods from agriculture, poultry, and seafood origin.     

生物法制备壳聚糖的研究进展

壳聚糖是一种具有独特特性的、可广泛地、有效地应用于工业和生物医药的生物高分子物质。本文综述了目前包括采用甲壳素酶法脱乙酰、生物培养及从发酵工厂废菌体中提取的生物法制备壳聚糖的研究状况,并对其应用前景作了展望。     

Production,properties, and some new applications of chitin and its derivatives

Chitin is a polysaccharide composed from N-acetyl-D-glucosamine units. It is the second most abundant biopolymer on Earth and found mainly in invertebrates, insects, marine diatoms, algae, fungi, and yeasts. Recent investigations confirm the suitability of chitin and its derivatives in chemistry, biotechnology, medicine, veterinary, dentistry, agriculture, food processing, environmental protection, and textile production. The development of technologies based on the utilization of chitin derivatives is caused by their polyelectrolite properties, the presence of reactive functional groups, gel-forming ability, high adsorption capacity, biodegradability and bacteriostatic, and fungistatic and antitumour influence. Resources of chitin for industrial processing are crustacean shells and fungal mycelia. Fungi contain also chitosan, the product of N-deacetylation of chitin. Traditionally, chitin is isolated from crustacean shells by demineralization with diluted acid and deproteinization in a hot base solution. Furthermore, chitin is converted to chitosan by deacetylation in concentrated NaOH solution. It causes changes in molecular weight and a degree of deacetylation of the product and degradation of nutritionally valuable proteins. Thus, enzymatic procedures for deproteinization of the shells or mold mycelia and for chitin deacetylation were investigated. These studies show that chitin is resistant to enzymatic deacetylation. However, chitin deacetylated partially by chemical treatment can be processed further by deacetylase. Efficiency of enzymatic deproteinization depends on the source of crustacean offal and the process conditions. Mild enzymatic treatment removes about 90% of the protein and carotenoids from shrimp-processing waste, and the carotenoprotein produced is useful for feed supplementation. In contrast, deproteinization of shrimp shells by Alcalase led to the isolation of chitin containing about 4.5% of protein impurities and recovery of protein hydrolysate.     

Growth of soybean sprouts affected by chitosans prepared under various deproteinization and demineralization times

Chitosan, a natural biopolymer derived by deacetylation of chitin, has been extensively used in biomedical, agricultural and food applications. The ultimate aim of research effort was to develop various economic/simplified chitosan production processes for particular food applications. Therefore, a set of experiments was designed to evaluate the effect of chitosans prepared under various deproteinization (DP) times (at 0, 5 and 15 min) and demineralization (DM) times (at 0, 10, 20 and 30 min) on the growth of soybean sprouts. Chitosan treatment increased the total weight of soybean sprouts by 10.7–13.8% compared with that of the control; the effectiveness of the chitosan treatment was independent of DP and DM times. The increase (12.7%) in the growth of soybean sprouts by chitosan prepared without DP and DM steps was noteworthy. This investigation demonstrates that the elimination of DP and DM steps or a reduction in the reaction time required for optimum DP and DM in the production of chitosan needs further studies before being considered for particular usages. Copyright © 2006 Society of Chemical Industry     

Chitin--the undisputed biomolecule of great potential

Of the truly abundant polysaccharides in Nature, only chitin has yet to find utilization in large quantity. Chitin is the second most abundant natural biopolymer derived from exoskeletons of crustaceans and also from cell walls of fungi and insects. Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine (GlcNAc), whereas chitosan, a copolymer of GlcNAc (approximately 20%) and glucosamine (GlcN, 80%) residues, is a product derived from de-N-acetylation of chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated chitins deacetylated to different degrees. Both chitin/chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. Their application versatility is a great challenge to the scientific community and to industry. All these are the result of their versatile biological activity, excellent biocompatibility, and complete biodegradability in combination with low toxicity. Commercial availability of high-purity forms of chitin/chitosan and the continuous appearance of new types of chitin/chitosan derivatives with more and more useful and specific properties have led to an unlimited R&D efforts on this most versatile amino polysaccharide, chitin to find new applications, which are necessary to realize its full potential. Incidentally, this too has become an environmental priority. No doubt, chitin is surely an undisputed biomolecule of great potential.     

Zein-based anti-browning cling wraps for fresh-cut apple slices

The usage of cling wraps is emerging as an easy and cost-effective approach to protect fresh-cut fruits and vegetables from dust, whilst improving visual appeal on retail counters. This study focused on developing an alternate, protein-based packaging material as a food grade cling wrap for food packaging applications. Zein-based cling wraps were produced, and their physical and mechanical characteristics were evaluated and compared with conventionally used chitosan biopolymer films and commercial synthetic polymer films. Antioxidant potential of the prepared films was studied, and the effectiveness of the developed films as anti-browning cling wraps was evaluated using studies conducted on fresh-cut apple slices at ambient conditions. Anti-browning effects were in par with polymeric counterparts; however, zein cling wraps could better prevent weight loss in apple slices. Zein-based films can be adopted as biodegradable food grade cling wraps as an alternative to chitosan and synthetic polymeric materials.     

Recent advances in biopolymers and biopolymer-based nanocomposites for food packaging materials

Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.     

黄原胶的特性、生产及应用进展

黄原胶是Xanthomnas.sp分泌的胞外水溶性多糖,由于其有突出的高粘性和水溶性、独特的流变特性、优良的温度稳定性和pH稳定性、极好的兼容性以及安全环保等特性,已被广泛于石油开采、食品工业、纺织和化妆品等诸多行业。主要综述了黄原胶的分子结构、分子特性、生产以及应用的研究进展。     

壳聚糖脱乙酰度的测定及其应用研究进展

壳聚糖是自然界中存量巨大的多糖类物质,在食品、医药、农业、环保等领域发挥着许多重要的作用.其脱乙酰度是评判其性能的重要指标之一,这使得在实际应用中对脱乙酰度检测方法的便利性和准确性提出较高的要求.本文综述了化学分析方法、光谱学分析方法、破坏性分析方法和电特性分析方法,探讨各种分析方法及其改进方案的优缺点,发现化学分析法...     

Chitosan application for active bio-based films production and potential in the food industry: Review

During the past decade, there was an increasing interest to develop and use bio-based active films which are characterized by antimicrobial and antifungal activities in order to improve food preservation and to reduce the use of chemical preservatives. Biologically active bio-molecules such as chitosan and its derivatives have a significant potential in the food industry in view of contaminations associated with food products and the increasing concerns in relation with the negative environmental impact of conventional packaging materials such as plastics. Chitosan offers real potential for applications in the food industry due to its particular physico-chemical properties, short time biodegradability, biocompatibility with human tissues, antimicrobial an antifungal activities, and non-toxicity. Thus, chitosan-based films have attracted serious attention in food preservation and packaging technology. This is mainly due to a fact that chitosan exhibits high antimicrobial activity against pathogenic and spoilage micro-organisms, including fungi, and both Gram-positive and Gram-negative bacteria. The aim of the present review was to summarize the most important information on chitosan from its bioactivity point of view and to highlight various preparative methods used for chitosan-based active bio-films and their potential for applications in the food preservation and packaging technology.     

Industrial applications of crustacean by-products (chitin,chitosan, and chitooligosaccharides): A review

BackgroundFood processing produces large quantities of by-products. Disposal of waste can lead to environmental and human health problems, yet often they can be turned into high value, useful products. For example, crustacean shell wastes from shrimp, crab, lobster, and krill contain large amounts of chitin, a polysaccharide that may be extracted after deproteinisation and demineralization of the exoskeletons.Scope and approachThis review summarizes the current state of knowledge of these crustacean shellfish wastes and the various ways to use chitin. This biopolymer and its derivatives, such as chitosan, have many biological activities (e.g., anti-cancer, antioxidant, and immune-enhancing) and can be used in various applications (e.g., medical, cosmetic, food, and textile).Key findings and conclusionsDue to the huge waste produced each year by the shellfish processing industry and the absence of waste management which represent an environmental hazard, the extraction of chitin from crustaceans’ shells may be a solution to minimize the waste and to produce valuable compound which possess biological properties with application in many fields. As a food waste, it is important to also be aware of the non-food uses of these wastes.     

壳聚糖国际研究之趋势

壳聚糖（Chitosan),又名甲壳素,几丁糖,是近年来最受注目的天然食品纤维之。与其它食品纤维之主要不同之处为其分子上之正电荷,产生多种功能,应用方式广泛,近年又有许多壳聚糖衍生物。增加更多功能。壳聚糖之主要功能包括吸附脂肪酸,胆固醇等,减少人体吸收。同时也可减缓高血压及糖尿病症状,增加细胞免疫功能,相关医学研究献甚多。因此成为健康食品业界之宠儿。壳聚糖以其特殊之基,在不同的酸碱值之环境中会有不同之吸附阴离子能力。因此对特殊香气,调味料及色素会有控释作用,延长此等分子在食品中之寿命。其应用也以衍生至药品之配方调制以延长药品之疗效。壳聚糖之种种特殊功能,源自其正电荷及分子量之搭配。而正电荷有来自其分子之脱乙酰度。以往对于壳聚糖之研究往往未注意及此。近年来由于加工技术进步,脱乙酰度已可高达99％。实验证明其物理化学性能均有其特殊功能,较以往一般脱乙酰度仅为80％显不同。而壳聚糖之单体－－葡萄糖（Glucoseamine)则医学界重视其缓解关节炎病症之效果。各种寡糖级聚合物（聚合度2－9之间）则似乎有较高之提升免疫机能之效果。因此其利用亦扩及纺织业,医疗器材等,均已产品上市。壳聚糖之功能多样化,前途未可限量。但其天然来源虽号称仅次于纤维,每年可达1万亿t。但容易取得之工业化来源仅为虾蟹等水产加工厂之副产品。全世界每年不过75,000t而已。故形成此工业发展之隐忧。欲再上一层楼,有必要开发不同来源,同时继续发展高附加价值之用途以充分利用此种资源。目前以基因工程研究各种提高产量之方法,亦是国际上热门之话题。     

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.     

Nanostructured Materials Utilized in Biopolymer-based Plastics for Food Packaging Applications

Most materials currently used for food packaging are nondegradable, generating environmental problems. Several biopolymers have been exploited to develop materials for ecofriendly food packaging. However, the use of biopolymers has been limited because of their usually poor mechanical and barrier properties, which may be improved by adding reinforcing compounds (fillers), forming composites. Most reinforced materials present poor matrix–filler interactions, which tend to improve with decreasing filler dimensions. The use of fillers with at least one nanoscale dimension (nanoparticles) produces nanocomposites. Nanoparticles have proportionally larger surface area than their microscale counterparts, which favors the filler–matrix interactions and the performance of the resulting material. Besides nanoreinforcements, nanoparticles can have other functions when added to a polymer, such as antimicrobial activity, etc. in this review paper, the structure and properties of main kinds of nanostructured materials which have been studied to use as nanofiller in biopolymer matrices are overviewed, as well as their effects and applications.     

磁性甲壳素/壳聚糖复合材料在食品安全检测中的应用研究进展

重金属污染水体、农兽药残留超标及人工色素的非法添加等引发的食品安全问题屡见不鲜,是人们一直关注的热点问题,因此选择合适的样品前处理方法尤为重要.甲壳素/壳聚糖纳米复合材料具有丰富的官能团、良好的机械性能、耐水性和无毒性等优点,是一种很好的吸附材料.磁性材料具有超顺磁性,能够通过外界磁场的驱动从溶液中迅速分离.将甲壳素/...     

Silk fibroin-based films in food packaging applications: A review

Plastic pollution is a significant concern nowadays due to wastes generated from non-biodegradable and non-renewable synthetic materials. In particular, most plastic food packaging material ends up in landfills, creating mass wastes that clog the drainage system and pollute the ocean. Thus, studies on various biopolymers have been promoted to replace synthetic polymers in food packaging and consequently, the high number of research in biopolymers food packaging, especially in the characterization, properties and also the development of the biopolymer. For biopolymer-based food packaging, silk fibroin (SF) has been highlighted because of its biodegradability and low water vapor permeability properties. This review focuses on the different properties of SF films prepared through solution casting and electrospinning for food packaging. Discussions encompassed chemical properties, mechanical properties, permeability, and biodegradability. This review also discussed the studies that used SF as the biomaterial for food packaging.     

Microbial biofilm activity and physicochemical characterization of biodegradable and edible cups obtained from abdominal exoskeleton of an insect

A contemporary focus in food industry is the use of edible bio-based products with properties such as antimicrobial and biodegradable to replace the synthetic harmful petroleum-based polymers. Among the natural polysaccharides, chitin has generated considerable research interest thanks to its biocompatibility and abundance. This study investigated the production of chitin bio-cups from abdominal exoskeleton of an insect as an alternative to synthetic materials in food processing industry. The physicochemical properties of the obtained chitin and chitosan cups were studied by FT-IR, TGA, XRD and SEM analyses. The purity of the extracted chitin was examined by chitinase digestive test. The microbial biofilm formation on the cups was tested and no growth was recorded for the common food pathogen bacteria (Listeria monocytogenes) and yeast (Candida albicans). Considering the antimicrobial, antioxidant, nontoxic and edible nature of chitin and chitosan, these cups can be suggested as an alternative bioplastic for food protection.Industrial relevanceIn recent years much research has focused on the use of nontoxic and edible biopolymers as film and coating material in food industry to eliminate the use of carcinogenic and harmful petroleum products. Among the biopolymers, chitin and its deacetylated form, chitosan, are attracting widespread interest thanks to their nontoxic, biodegradable and edible properties. Here in this study, we investigated the production of chitin bio-cups from abdominal exoskeleton of an insect as an alternative to synthetic materials in food processing industry.     

Characterization of antimicrobial properties on the growth of S. aureus of novel renewable blends of gliadins and chitosan of interest in food packaging and coating applications

The biocide properties of chitosan-based materials have been known for many years. However, typical antimicrobial formulations of chitosan, mostly chitosonium salts, are known to be very water sensitive materials which may impair their use in many application fields such as food packaging or food coating applications. This first work reports on the development and characterization of the antimicrobial properties of novel fully renewable blends of chitosan with more water-resistant gliadin proteins isolated from wheat gluten. Chitosan release to the nutrient broth from a wide range of blends was studied making use of the ninhydrin method. The results indicated that both pure chitosan and its blends with gliadins presented significant antimicrobial activity, which increased with increasing the amount of chitosan in the composite formulation as expected. The gliadins-chitosan blends showed good transparency and film-forming properties and better water resistance than pure chitosan. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with the amount of chitosan present in the formulation. The release of these groups was for the first time directly correlated with the antimicrobial properties exhibited by the blends. Thus, incorporation of chitosan into an insoluble biopolymer matrix was revealed as a very feasible strategy to generate novel chitosan-based antimicrobial materials with potential advantages, for instance active food packaging applications.     

新食品原料壳寡糖的酶法生产研究

目的针对高分子原料壳聚糖在食品工业应用中的两大难题——清洁生产与安全食用,研究了内切壳聚糖酶EC.3.2.1.132在新食品原料壳寡糖工业生产中的应用。方法通过广泛筛查,选育产酶活性高、性能稳定、具有单一内切模式的野生菌种。综合应用生物工程技术构建高效表达的基因重组工程菌,经优化发酵条件、建立简易纯化方法,获得了专一性内切壳聚糖酶。采用循环型清洁生产工艺用于新食品原料壳寡糖的工业化生产。结果从产酶量10 U/mL左右的野生型曲霉菌株Jxsd-01获得成熟基因,构建重组毕赤酵母工程菌表达体系,内切壳聚糖酶蛋白产量达到0.95 g/L。采用循环型清洁生产工艺酶法生产的壳寡糖含量高达98%,聚合度n=2~10,原料转化率95%以上,生产过程中无废水、废渣产生。结论内切壳聚糖酶应用于食品工业,实现新食品原料壳寡糖的工业化酶法生产,达到清洁、安全、高效的效果,具有应用推广的价值。     

Applications of Chitosan in the Seafood Industry and Aquaculture: A Review

There has recently been an increasing interest in seafood products due to the growing awareness of their nutraceutical value. However, marine-based products are highly susceptible to deterioration, mainly because of their high contents of polyunsaturated fatty acids (PUFAs), their high water activity, abundant free amino acids, neutral pH, and the presence of autolytic enzymes. In recent decades, various alternative methods have been developed to address this issue. Among the proposed solutions, chitosan has been highlighted as one of the most promising solutions. Chitosan, a deacetylated derivative of chitin, has attracted high consideration for its nontoxicity, biocompatibility, and biodegradability. Moreover, it is a polymer with versatile functional properties. For this reason, chitosan, which is commercially produced mostly from marine sources (e.g., crustacean shells), has been used to stabilize seafood-based products. In this review, chitosan is highlighted with respect to the various potential applications exploiting its many features, such as antibacterial and antioxidant properties, edible film- and coating-forming ability, the treatment of seafood industry effluent, enhanced gelling properties, micro- and nanocarrier abilities for bioactive compounds, functional foods, and drug compounds from aquaculture and seafood.