Current applications of exopolysaccharides from lactic acid bacteria in the development of food active edible packaging

Current state, challenges and future orientations of the applications of lactic acid bacteria exopolysaccharide in foods

In the quest for a balanced diet and better health, the global shift towards nutrient-dense foods highlights the multiple roles of lactic acid bacteria exopolysaccharides (LAB-EPS) in improving food quality and health. This paper offers a comprehensive survey of LAB-EPS, focusing on their classification, biosynthesis pathways and application in the food industry, from dairy products to bakery products and meat. It highlights the impact of LAB-EPS on the texture and sensory qualities of food. Despite their promising prospects, these polysaccharides face various application challenges in the food industry. These include variability in EPS production among LAB strains, complexity in structure-function relationships, and limited understanding of their health benefits. In order to address these issues, the review identifies and suggests future research directions to optimize the production of LAB-EPS, elucidating their health benefit mechanisms, and expanding their application scope. In summary, this review aims to contribute to advance innovation and progress in the food industry by developing healthier food options and deepening the understanding of LAB-EPS in promoting human health.

Transforming Agro-Industrial Waste into Bioplastic Coating Films

Addressing the environmental impact of agro-industrial waste, this study explores the transformation of banana, potato, and orange peels into bioplastics suitable for thin coating films. We prepared six extracts at 100 g/L, encompassing individual (banana peel, BP; orange peel, OP; and potato peel, PP) and combined [BP/OP, BP/PP, and BP/OP/PP] formulations, with yeast mold (YM) medium serving as the control. Utilizing the spin-coating method, we applied 1 mL of each sample at 1000 rpm for 1 min to create the films. Notably, the OP extract demonstrated a twofold increase in bioplastic yield (860.33 mg/L) compared to the yields of BP (391.43 mg/L), PP (357.67 mg/L), BP/OP (469.40 mg/L), BP/PP (382.50 mg/L), BP/OP/PP (272.67 mg/L), and YM (416.33 mg/L) extracts. Atomic force microscopy analysis of the film surfaces revealed a roughness under 8 nm, with the OP extract recording the highest at 7.0275 nm, whereas the BP/OP mixture exhibited the lowest roughness at 0.2067 nm and also formed the thinnest film at 6.5 nm. With R2 trend values exceeding 0.9950, the films exhibited water vapor permeability values ranging from 3.05 × 10-3 to 4.44 × 10-3, with the OP film being the least permeable and the BP/PP films the most permeable. The OP film demonstrated the lowest solubility in both water and ethanol with values of 64.71 and 1.05%, respectively. The solubilities of all films were above 60% in water and below 4% in ethanol. Furthermore, the films exhibited antimicrobial efficacy against both Gram-positive and Gram-negative bacteria. Our findings confirm the potential of utilizing banana, orange, and potato peels as viable substrates for eco-friendly bioplastics in thin-film applications.

Edible packaging as sustainable alternative to synthetic plastic: a comprehensive review

The choice of an appropriate packaging materials enhances the shelf life and improves quality of food during transportation, storage, and distribution. Development and innovations in food packaging systems have become essential in the food industry. Most widely used packaging materials are non-biodegradable plastics and are harmful to environment and human health. Thus, food industry is replacing non-biodegradable plastics with biodegradable plastics to reduce environmental pollution, health hazards, and food waste. Edible packaging may reduce food waste and keep perishables fresh. This review article compares edible packaging materials to synthetic ones and discusses their pollution-reducing effects. The several types of food packaging discussed in the review include those produced from polysaccharides, proteins, lipids, and composite films. The various characteristics of edible packaging are reviewed, including its barrier qualities, carrier properties, mechanical capabilities, and edibility. The carrier properties describe the capacity to transport and manage the release of active substances, and the edibility indicates acceptance of these items by the customers. Plasticizers, antimicrobials, antioxidants, and emulsifiers were included in the edible packaging to enhance the characteristics of the film. The development and implementation of edible packaging on food products from the laboratory to large-scale industrial levels, as well as their potential industrial applications in the dairy, meat, confectionary, poultry, fish, fruit, and vegetable processing sectors are addressed.

Exopolysaccharides of lactic acid bacteria: Structure, biological activity, structure-activity relationship, and application in the food industry: A review

Over the past few decades, researchers have discovered that probiotics play an important role in our daily lives. With the further deepening of research, more and more evidence show that bacterial metabolites have an important role in food and human health, which opens up a new direction for the research of lactic acid bacteria (LAB) in the food and pharmaceutical industry. Many LAB have been widely studied because of the ability of exopolysaccharides (EPS). Lactic acid bacteria exopolysaccharides (LAB EPS) not only have great potential in the treatment of human diseases but also can become natural ingredients in the food industry to provide special qualitative structure and flavor. This paper has organized and summarized the biosynthesis, strain selection, production process parameters, structure, and biological activity of LAB EPS, filling in the monotony and incompleteness of previous articles' descriptions of LAB EPS. Therefore, this paper focuses on the general biosynthetic pathway, structural characterization, structure-activity relationship, biological activity of LAB EPS, and their application in the food industry, which will help to deepen people's understanding of LAB EPS and develop new active drugs from LAB EPS. Although the research results are relatively affluent, the low yield, complex structure, and few clinical trials of EPS are still the reasons that hinder its development. Therefore, future knowledge expansion should focus on the regulation of structure, physicochemical properties, function, higher production of EPS, and clinical trial applications, which can further increase the commercial significance and value of EPS. Furthermore, better understanding the structure-function relationship of EPS in food remains a challenge to date.

Advanced biopolymer-based edible coating technologies for food preservation and packaging

Along with the growth of the world's population that reduces the accessibility of arable land and water, demand for food, as the fundamental element of human beings, has been continuously increasing each day. This situation not only becomes a challenge for the modern food chain systems but also affects food availability throughout the world. Edible coating is expected to play a significant role in food preservation and packaging, where this technique can reduce the number of food loss and subsequently ensure more sustainable food and agriculture production through various mechanisms. This review provides comprehensive information related to the currently available advanced technologies of coating applications, which include advanced methods (i.e., nanoscale and multilayer coating methods) and advanced properties (i.e., active, self-healing, and super hydrophobic coating properties). Furthermore, the benefits and drawbacks of those technologies during their applications on foods are also discussed. For further research, opportunities are foreseen to develop robust edible coating methods by combining multiple advanced technologies for large-scale and more sustainable industrial production.

Immunomodulatory activity and protective effect of a capsular polysaccharide in Caenorhabditis elegans, isolated from Lactobacillus fermentum GBJ

A capsular polysaccharide, namely CPS-2, was isolated from Lactobacillus fermentum GBJ, purified using DEAE-52 anion exchange chromatography, and structurally characterized. We found that CPS-2 is homogenous, has an average molecular weight of 377 KDa, and is mainly composed of galactose and glucose at a molar ratio of 1.54:1.00. Its backbone comprises α-D-Galp-(1 → 3), α-D-Galp-(1 → 3,6), β-D-Glcp-(1 → 2), β-D-Galp-(1 → 6), and α-D-Galp-(1 → 4) residues with a side chain of β-D-Glcp-(1→). CPS-2 exerts an immunomodulatory effect by improving the proliferation and phagocytosis of macrophage RAW264.7 and promoting the secretion of NO and cytokines. The maximum secretion levels of IL-1β, IL-6, IL-10, and TNF-α were 1.96-, 0.11-, 0.22-, and 0.46-fold higher than those of the control, respectively. Furthermore, CPS-2 could significantly enhance the antioxidant system, extend lifespan, and improve stress tolerance of Caenorhabditis elegans at both exposure doses of 31.25 and 62.5 μg/mL. The average lifespan of nematodes reached a maximum in the 62.5 μg/mL-treated group after 10.39 days, 6.56 h, and 23.56 h in normal, oxidative stress, and heat shock environment, with extension percentages of 16.61 %, 43.23 %, and 15.77 %, respectively; therefore, CPS-2 displays an anti-aging effect. The significant bioactivity of CPS-2 promotes its application as a promising immunomodulatory and anti-aging ingredient in the food or pharmaceutical field.

Encapsulating potential and functional properties of exopolysaccharide from Limosilactobacillus reuteri KCTC 14626BP isolated from human breast milk

Exopolysaccharides (EPS) are natural, nontoxic, biocompatible and biodegradable macromolecules produced by microorganisms, including the Lactic acid bacteria, to enhance protection against environmental stress conditions. The current study focused on the encapsulation and functional efficiency of EPS produced by probiotic strains isolated from human milk. Among 27 isolates, the potential high EPS-producing strain Limosilactobacillus reuteri KCTC 14626BP was selected based on biofilm production. The structural Characterization of EPS was performed based on FTIR, NMR and functional properties were determined; further, the encapsulation efficiency of EPS was determined with caffeic acid. The results indicate that L. reuteri produced EPS major component consisting of glucose, galactose and arabinose with the ratio of (0.78:0.16: 0.05). The antioxidant efficiency of EPS-LR was determined on DPPH (60.3 %) and ABTS (48.9 %); EPS showed enhanced functional activities. The absence of toxicity was confirmed based on Caenorhabditis elegans. The EPS-loaded Caffeic acid (CA) EPS-LR indicated spherical capsules with rough surfaces, with sizes ranging from 1.39 to 6.75 μm. These findings indicate that EPS-LR can be applied as a bioactive compound and encapsulating material in food, cosmetics, and pharmaceutical industries.

Microbial exopolysaccharide: Sources, stress conditions, properties and application in food and environment: A comprehensive review

Microbial glucan or exopolysaccharides (EPS) have caught an eye of researchers from decades. The unique characteristics of EPS make it suitable for various food and environmental applications. This review overviews the different types of exopolysaccharides, sources, stress conditions, properties, characterization techniques and applications in food and environment. The yield and production condition of EPS is a major factor affecting the cost and its applications. Stress conditions are very important as it stimulates the microorganism for enhanced EPS production and affects its properties. As far as application is concerned specific properties of EPS such as, hydrophilicity, less oil uptake behavior, film forming ability, adsorption potential have applications in both food and environment sector. Novel and improved method of production, feed stock and right choice of microorganisms with stress conditions are critical for desired functionality and yield of the EPS.

Biological activities and applications of exopolysaccharides produced by lactic acid bacteria: a mini-review

Exopolysaccharides (EPSs) are naturally occurring high-molecular-weight carbohydrates that have been widely studied for their biological activities, including antioxidant, immunomodulatory, anticancer and gut microbiota regulation activities. Polysaccharides are abundant in nature and can be derived from animals, plants, algae, and microorganisms, but among polysaccharides with potential uses, EPSs from microorganisms have the advantages of a short production cycle, high yield, and independence of production from season and climate and thus have broad prospects. While the safety of the producing microorganism can represent a problem in application of microbial EPSs, lactic acid bacteria (LAB) have been used by humans for thousands of years, and they and their products are generally recognized as safe. This makes LAB excellent sources for exopolysaccharides. EPS-producing LAB are readily found in nature. Through screening of strains, optimization of culture conditions, and improvement of the growth medium, the yield of EPSs from LAB can be increased and the scope of application broadened. This review summarizes EPSs from LAB in terms of structure, function and applications, as well as yield optimization, and introduces recent research on the biological activities and practical applications of LAB EPSs, aiming to provide references for researchers in related areas.

Biopolymers Produced by Lactic Acid Bacteria: Characterization and Food Application

Plants, animals, bacteria, and food waste are subjects of intensive research, as they are biological sources for the production of biopolymers. The topic links to global challenges related to the extended life cycle of products, and circular economy objectives. A severe and well-known threat to the environment, the non-biodegradability of plastics obliges different stakeholders to find legislative and technical solutions for producing valuable polymers which are biodegradable and also exhibit better characteristics for packaging products. Microorganisms are recognized nowadays as exciting sources for the production of biopolymers with applications in the food industry, package production, and several other fields. Ubiquitous organisms, lactic acid bacteria (LAB) are well studied for the production of exopolysaccharides (EPS), but much less as producers of polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). Based on their good biodegradability feature, as well as the possibility to be obtained from cheap biomass, PLA and PHAs polymers currently receive increased attention from both research and industry. The present review aims to provide an overview of LAB strains' characteristics that render them candidates for the biosynthesis of EPS, PLA, and PHAs, respectively. Further, the biopolymers' features are described in correlation with their application in different food industry fields and for food packaging. Having in view that the production costs of the polymers constitute their major drawback, alternative solutions of biosynthesis in economic terms are discussed.

Providing Antimicrobial Properties to Cardboard Food Packaging by Coating with ZnO, TiO2, and SiO2—Water-Based Varnish Nanocomposites

Packaging acts like a bond between visual communication and production technology. Packaging material is often coated to enhance visual appearance and some protective features. The COVID pandemic changed consumers’ behavior and understanding of the importance regarding the antimicrobial properties of goods that come in contact with hands. The aim of this research is to investigate and determine the antimicrobial properties of nanocomposite coatings which include nanosized zinc oxide (ZnO), titanium dioxide (TiO2), and silicon dioxide (SiO2). For the purpose of this research, a lithographic printed packaging was coated with a nanocomposite composed of flexographic water-based varnish with incorporated ZnO, TiO2, and SiO2 nanosized particles. A total of eight modulations were presented and compared to the lone water-based varnish. The results have shown that applying nanocomposites will increase the total surface free energy of the packaging surface but will decrease the polar component of the surface free energy leading to lower hydrophilic properties. Both nanocomposite types showed that the increase in the nanoparticle weight ratio leads to higher protection benefits. Nanocomposites with ZnO have better antimicrobial activity than the ones with TiO2. The Hybrid/Z (ZnO + SiO2) significantly improved the antimicrobial capacity of water-based varnish, primarily against the ubiquitous foodborne pathogen Listeria monocytogenes.

Need for Sustainable Packaging: An Overview

Packaging materials are a significant part of our lives due to their daily usage at grocery stores, supermarkets, restaurants, pharmaceuticals, etc. Packaging plays an important role in ensuring that the products are preserved during handling, transporting, and storage. Similarly, it helps to maintain and prolong the shelf life of products. These materials are used for packaging meats, poultry and seafood products, food and beverages, cosmetics, and pharmaceutical products. Several applications of packaging materials have been discussed extensively, with little discussion on their end of life and continuous availability without impacting the environment. This study presents the need for sustainable packaging as a result of growing demands and the environmental impact of packaging materials after use. This study also presents the importance, types, and applications of packaging materials. Based on the findings of this study, sustainable packaging is made possible by using bio-based and recyclable materials. These materials contribute a great deal to protecting and ensuring a sustainable environment.

Reduction of biogenic amines formation by foodborne pathogens using postbiotics in lysine-decarboxylase broth

Postbiotics is a novel term proposed to describe as a set of bioactive compounds obtained from beneficial microorganisms. In this work, postbiotics from four lactic acid bacteria (LAB) including Leuconostoc mesenteroides subsp. cremoris, Pediococcus acidilactici, Lactococcus lactis subsp. lactis and Streptococcus thermophilus were prepared in MRS broth. The antimicrobial properties and organic acids content of postbiotics were also investigated. Postbiotics were used to tentatively reduce the production of biogenic amines by foodborne pathogens (i.e., Salmonella paratyphi A and Escherichia coli) on lysine decarboxylase broth (LDB). Experimental data showed that acetic, propionic, and butyric acids were in the range of 387.51-709.21 mg/L, 0.00-1.28 mg/L, and 0.00-20.98 mg/L, respectively. The inhibition zone of postbiotics on E. coli and S. paratyphi A were 11.67, and 12.33 mm, respectively. Two different levels of postbiotics (25%, and 50%) were used in LDB to measure the diamines (cadaverine and putrescine), polyamines (agmatine, spermidine, and spermine, ammonia), and other biogenic amine formation by pathogens. E. coli produced cadaverine and putrescine with concentrations of 1072.21 and 1114.18 mg/L, respectively. The postbiotics reduced cadaverine formation by 67% in E. coli, and cadaverine production was mostly suppressed by postbiotics from P. acidilactici in E. coli (97%) and L. lactis subsp. lactis in S. paratyphi A (90%). Putrescine production by E. coli was reduced by 94% with postbiotics of P. acidilactici at a concentration of 25%, whereas putrescine production by S. paratyphi A has been decreased by 61% in the presence of postbiotics from L. lactis subsp. Lactis with a 25% concentration. The results revealed that an increase in postbiotics concentration (from 25% to 50%) in LDB may lead to synergistic effects, resulting from the production of biogenic amines by microbial pathogens. It was importantly concluded that postbiotics of LAB may degrade biogenic amines or prevent their formation by foodborne pathogens.

Food Packaging Materials with Special Reference to Biopolymers-Properties and Applications

Food is an important material for survival. The increasing world population, urbanization, and globalization are responsible for more food. This has increased challenges in food storage and safety. Therefore, it is necessary to preserve food by suitable packaging materials. The packaging materials are useful for giving longer life to the food and improving quality during transportation, storage and distribution. Innovations and developments in food packaging, have become very important in the food industry. Variety of packaging materials such as plastics, paper, metal, and glass are used in food packaging. Most widely used packaging materials are non-biodegradable plastics but these are harmful to environment and human health. Therefore, the food industry is in search of environment friendly replacement of non-biodegradable plastics by biodegradable plastics. However, no systematic literature is available on the subject, so there is a need to summarise the available information in a systematic way. Polymer packaging materials with special reference to biodegradable plastics have been discussed in detail. Different type of biodegradable plastics with their functionality and applications in food packaging have been summarised. Literature available has shown that biodegradable plastics are much better for food packaging as compared to other packaging materials. Increasing fundamental research in the use of biodegradable polymers in food packaging and effort to protect the environment, requires deep understanding and there are lot of challenges for commercialization, which are to be tackled. All these aspects have been discussed in this review article.

Characterisation of recombinant GH 3 β-glucosidase from β-glucan producing Levilactobacillus brevis TMW 1.2112

Levilactobacillus (L.) brevis TMW 1.2112 is an isolate from wheat beer that produces O2-substituted (1,3)-β-D-glucan, a capsular exopolysaccharide (EPS) from activated sugar nucleotide precursors by use of a glycosyltransferase. Within the genome sequence of L. brevis TMW 1.2112 enzymes of the glycoside hydrolases families were identified. Glycoside hydrolases (GH) are carbohydrate-active enzymes, able to hydrolyse glycosidic bonds. The enzyme β-glucosidase BglB (AZI09_02170) was heterologous expressed in Escherichia coli BL21. BglB has a monomeric structure of 83.5 kDa and is a member of the glycoside hydrolase family 3 (GH 3) which strongly favoured substrates with β-glycosidic bonds. Km was 0.22 mM for pNP β-D-glucopyranoside demonstrating a high affinity of the recombinant enzyme for the substrate. Enzymes able to degrade the (1,3)-β-D-glucan of L. brevis TMW 1.2112 have not yet been described. However, BglB showed only a low hydrolytic activity towards the EPS, which was measured by means of the D-glucose releases. Besides, characterised GH 3 β-glucosidases from various lactic acid bacteria (LAB) were phylogenetically analysed to identify connections in terms of enzymatic activity and β-glucan formation. This revealed that the family of GH 3 β-glucosidases of LABs comprises most likely exo-active enzymes which are not directly associated with the ability of these LAB to produce EPS.

Antifungal Mechanisms and Application of Lactic Acid Bacteria in Bakery Products: A Review

Bakery products are nutritious, but they are susceptible to fungal contamination, which leads to a decline in quality and safety. Chemical preservatives are often used to extend the shelf-life of bakery products, but long-term consumption of these preservatives may increase the risk of chronic diseases. Consumers increasingly demand food with fewer chemical preservatives. The application of lactic acid bacteria (LAB) as a novel biological preservative not only prolongs the shelf-life of bakery products but also improves the baking properties of bakery products. This review summarizes different types and action mechanisms of antifungal compounds produced by LAB, factors affecting the production of antifungal compounds, and the effects of antifungal LAB on bakery products, providing a reference for future applications of antifungal LAB in bakery products.

Functional and health-promoting properties of probiotics' exopolysaccharides; isolation, characterization, and applications in the food industry

Exopolysaccharides (EPS) are extracellular sugar metabolites/polymers of some slim microorganisms and, a wide variety of probiotics have been broadly investigated for their ability to produce EPS. EPS originated from probiotics have potential applications in food, pharmaceutical, cosmetology, wastewater treatment, and textiles industries, nevertheless slight is recognized about their function. The present review purposes to comprehensively discuss the structure, classification, biosynthesis, extraction, purification, sources, health-promoting properties, techno-functional benefits, application in the food industry, safety, toxicology, analysis, and characterization methods of EPS originated from probiotic microorganisms. Various studies have shown that probiotic EPS used as stabilizers, emulsifiers, gelling agents, viscosifiers, and prebiotics can alter the nutritional, texture, and rheological characteristics of food and beverages and play a major role in improving the quality of these products. Numerous studies have also proven the beneficial health effects of probiotic EPS, including antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, anticancer, antidiabetic, antibiofilm, antiulcer, and antitoxin activities. Although the use of probiotic EPS has health effects and improves the organoleptic and textural properties of food and pharmaceutical products and there is a high tendency for their use in related industries, the production yield of these products is low and requires basic studies to support their products in large scale.

In situ exopolysaccharides produced by Lactobacillus helveticus MB2-1 and its effect on gel properties of Sayram ketteki yoghurt

In order to study the mechanism of high viscosity of Sayram ketteki yoghurt, the growth, acidification properties, in situ exopolysaccharides (EPS) production of Lactobacillus helveticus MB2-1 in milk medium were investigated. The microstructure of the yoghurt was analyzed. The characteristics of in situ EPS produced by this strain in yoghurt were studied by high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-vis) analysis. The amount of in situ EPS produced could be up to 689.47 mg/L. The micrographs of Sayram ketteki yoghurt demonstrated that the in situ EPS secreted by ropy L. helveticus MB2-1 were closely connected with proteins, effectively filling the three-dimensional network structure of casein clusters, thereby resulting in high viscosity of yoghurt. Besides, the molecular weight of in situ EPS was 9.34 × 10⁴ Da, and the in situ EPS was determined to be a new heteropolysaccharide, containing fucose, which made it unique. Moreover, the set yoghurts added with in situ EPS were demonstrated fine effects on the texture improvement. These results illustrated that L. helveticus MB2-1 could be set as a good starter and the in situ EPS could be considered as a probiotic stabilizer substitute for fermented dairy products.

Exopolysaccharides synthesized by lactic acid bacteria: biosynthesis pathway, structure-function relationship, structural modification and applicability

Probiotics and their fermentation products are increasingly been focused on due to their health-boosting effects. Exopolysaccharides (EPS) synthetized by lactic acid bacteria (LAB) are widely applied as texture modifiers in dairy, meat and bakery products owning to their improved properties. Moreover, LAB-derived EPS have been confirmed to possess diverse physiological bioactivities including antioxidant, anti-biofilm, antiviral, immune-regulatory or antitumor. However, the low production and high acquisition cost hinder their development. Even though LAB-derived EPS have been extensively studied for their production-improving, there are only few reports on the systematic elucidation and summary of the relationship among biosynthesis pathway, strain selection, production parameter, structure-function relationship. Therefore, a detailed summary on biosynthesis pathway, production parameter and structure-function relationship of LAB-derived EPS is provided in this review, the structural modifications together with the current and potential applications are also discussed in this paper.

Carbon dots synthesized from microorganisms and food by-products: active and smart food packaging applications

Nanotechnology is rapidly becoming a commercial reality for application in food packaging. In particular, the incorporation of nanoparticles into packaging materials is being used to increase the shelf life and safety of foods. Carbon dots (C-dots) have a diverse range of potential applications in food packaging. They can be synthesized from environmentally friendly sources such as microorganisms, food by-products, and waste streams, or they may be generated in foods during normal processing operations, such as cooking. These processes often produce nitrogen- and sulfur-rich heteroatom-doped C-dots, which are beneficial for certain applications. The incorporation of C-dots into food packaging materials can improve their mechanical, barrier, and preservative properties. Indeed, C-dots have been used as antioxidant, antimicrobial, photoluminescent, and UV-light blocker additives in food packaging materials to reduce the chemical deterioration and inhibit the growth of pathogenic and spoilage microorganisms in foods. This article reviews recent progress on the synthesis of C-dots from microorganisms and food by-products of animal origin. It then highlights their potential application for the development of active and intelligent food packaging materials. Finally, a discussion of current challenges and future trends is given.

Recent Advances in the Production of Exopolysaccharide (EPS) from Lactobacillus spp. and Its Application in the Food Industry: A Review

Exopolysaccharide (EPS) show remarkable properties in various food applications. In this review paper, EPS composition, structural characterization, biosynthesis pathways, and recent advancements in the context of application of EPS-producing Lactobacillus spp. in different food industries are discussed. Various chemical and physical properties of Lactobacillus EPS, such as the structural, rheological, and shelf-life enhancement of different food products, are mentioned. Moreover, EPSs play a characteristic role in starter culture techniques, yogurt production, immunomodulation, and potential prebiotics. It has been seen that the wastes of fermented and non-fermented products are used as biological food for EPS extraction. The main capabilities of probiotics are the use of EPS for technological properties such as texture and flavor enhancement, juiciness, and water holding capacities of specific food products. For these reasons, EPSs are used in functional and fermented food products to enhance the healthy activity of the human digestive system as well as for the benefit of the food industry to lower product damage and increase consumer demand. Additionally, some pseudocereals such as amaranth and quinoa that produce EPS also play an important role in improving the organoleptic properties of food-grade products. In conclusion, more attention should be given to sustainable extraction techniques of LAB EPS to enhance structural and functional use in the developmental process of food products to meet consumer preferences.

Food wastes as natural sources of lactic acid bacterial exopolysaccharides for the functional food industry: A review

Exopolysaccharides (EPSs) synthesized by lactic acid bacteria (LAB), have recently received much interest because of their various functional features in several industries. Food wastes (FWs) have become a major source of worry, as they can cause serious environmental contamination if improperly disposed. The utilization of these FWs is an excellent choice (approach) for producing value-added products such as EPSs, which will efficiently remediate wastes. The overall EPSs yield for the selected producers is strain-specific, and is heavily influenced by the nutritional and growing conditions used. This review emphasizes what is currently known about LAB's ability to generate economically relevant EPSs from FWs. In addition, a concise overview of the food industry, packaging, pharmaceutical and clinical applications application is discussed.

Current Advances on the Development and Application of Probiotic-Loaded Edible Films and Coatings for the Bioprotection of Fresh and Minimally Processed Fruit and Vegetables

The application of probiotics has emerged as an innovative bioprotection technology to preserve fresh and minimally processed fruit and vegetables. This review discusses the most recent advances on the development and application of probiotic-loaded edible films/coatings as a strategy to preserve fresh or minimally processed fruit and vegetables. Available studies have shown a variety of materials, including hydrocolloids (polysaccharides and proteins) and lipids, used alone or in combination to formulate edible films/coatings loaded with probiotics. Plasticizers and surfactants are usually required to formulate these edible films/coatings. The reported antimicrobial effects of probiotic-loaded edible films/coating and quality parameters of coated fruit and vegetables could vary according to the characteristics of the materials used in their formulation, loaded probiotic strain and its dose. The antimicrobial effects of these films/coatings could be linked to the action of various metabolites produced by embedded probiotic cells with inhibitory effects on microorganisms contaminating fruit and vegetable surfaces. The implication of the use of probiotic-loaded edible films/coatings should be their antimicrobial effects against pathogenic and spoilage microorganisms and efficacy to control the ripening of fruit and vegetables, helping the coated products to maintain their safety, quality, nutritional and functional characteristics for a more prolonged storage period.

Lactobacillus amylovorus derived lipase-mediated silver derivatization over poly(ε-caprolactone) towards antimicrobial coatings

Owing to the probiotic origin, lipases-derived from the Lactobacilli sp. are considered to be promising biomaterials for in vivo applications. On a different note, poly(ε-caprolactone) (PCL)-an FDA-approved polymer for implantable applications-lacks inherent antimicrobial property, because of which suitable modifications are required to render it with bactericidal activity. Here, we employ Lactobacillus amylovorous derived lipase to surface derivatize the PCL films with silver that is a highly efficient inorganic broad-spectrum antimicrobial substance. Two different surface functionalization strategies have been employed over the alkaline hydrolyzed PCL films towards this purpose: In the first strategy, lipase-capped silver nanoparticles (Ag NPs) have been synthesized in a first step, which have been covalently immobilized over the activated carboxylic groups on the PCL film surface in a subsequent step. In the second strategy, the lipase was covalently immobilized over the activated carboxylic groups of the PCL film surface in the first step, over which silver was deposited in the second step using the dip-coating method. While the characterization study using X-ray photoelectron spectroscopy (XPS) has revealed the successful derivatization of silver over the PCL film, the surface characterization using field-emission scanning electron microscopy (FE-SEM) study has shown a distinct morphological change with higher silver loading in both strategies. The antimicrobial studies employing E. coli have revealed 100 % inhibition in the bacterial growth in 4-6 h with the Ag NPs-immobilized PCL films as opposed to >8 h with those prepared through the dip-coating method. Additionally, the cytotoxicity assay using mouse fibroblast cells has shown that the PCL films immobilized with lipase-capped Ag NPs exhibit high cell compatibility, similar to that of pristine PCL film, and thereby making it suitable for in vivo applications.

Exopolysaccharides produced by Pediococcus acidilactici MT41-11 isolated from camel milk: Structural characteristics and bioactive properties

In this study, the chemical structure and bioactive properties of the EPS of Pediococcus acidilactici MT41-11 isolated from camel milk were investigated. Two polysaccharide fractions (EPS-1, EPS-2) with molecular weights about 69.0 kDa were obtained, which were purified using DEAE-Sepharose and Sephadex G-100 chromatography. Based on monosaccharide composition, FT-IR, and 1D, 2D NMR spectra, concluded that EPS-1 had a backbone composed of →2)-α-d-Manp-(1→, →3)-α-d-Manp-(1→ and with branches containing α-d-Manp-(1→, EPS-2 had a backbone composed of →6)-β-d-Glcp-(1→, and with branches containing →2)-α-l-Fucp-(1→, →3)-α-d-Glcp-(1→, →2)-α-d-Glcp-(1→, β-d-Glcp-(1→, and α-d-Glcp-(1→. Remarkably, in vitro assays showed that EPS possessed multiple bioactive properties, including stimulating Lactobacillus growth and a high DPPH free radical scavenging activity. Also, it has a good ability to anti-biofilms. Overall, the analysis of all data showed EPS from P. acidilactici MT41-11 can be used as anti-oxidant, anti-biofilm agent, and also as a potential candidate prebiotic for health food or medicine industry.

A Review of the Applications and Biodegradation of Polyhydroxyalkanoates and Poly(lactic acid) and Its Composites

Overconsumption of plastic goods and improper handling of petroleum-derived plastic waste have brought a plethora of negative impacts to the environment, ecosystem and human health due to its recalcitrance to degradation. These drawbacks become the main driving force behind finding biopolymers with the degradable properties. With the advancement in biopolymer research, polyhydroxyalkanoate (PHA) and poly(lacyic acid) (PLA) and its composites have been alluded to as a potential alternative to replace the petrochemical counterpart. This review highlights the current synthesis process and application of PHAs and PLA and its composites for food packaging materials and coatings. These biopolymers can be further ameliorated to enhance their applicability and are discussed by including the current commercially available packaging products. Factors influencing biodegradation are outlined in the latter part of this review. The main aim of this review article is to organize the scattered available information on various aspects of PHAs and PLA, and its composites for packaging application purposes. It is evident from a literature survey of about 140 recently published papers from the past 15 years that PLA and PHA show excellent physical properties as potential food packaging materials.

The role of genetic manipulation and in situ modifications on production of bacterial nanocellulose: A review

Natural polysaccharides are well-known biomaterials because of their availability and low-cost, with applications in diverse fields. Cellulose, a renowned polysaccharide, can be obtained from different sources including plants, algae, and bacteria, but recently much attention has been paid to the microorganisms due to their potential of producing renewable compounds. In this regard, bacterial nanocellulose (BNC) is a novel type of nanocellulose material that is commercially synthesized mainly by Komagataeibacter spp. Characteristics such as purity, porosity, and remarkable mechanical properties made BNC a superior green biopolymer with applications in pharmacology, biomedicine, bioprocessing, and food. Genetic manipulation of BNC-producing strains and in situ modifications of the culturing conditions can lead to BNC with enhanced yield/productivity and properties. This review mainly highlights the role of genetic engineering of Komagataeibacter strains and co-culturing of bacterial strains with additives such as microorganisms and nanomaterials to synthesize BNC with improved functionality and productivity rate.

Application of Lactic Acid Bacteria in Fermentation Processes to Obtain Tannases Using Agro-Industrial Wastes

Bacteria have been used in the food industry to produce flavors, dyes, thickeners, and to increase food value, because bacterial fermentations favor the obtention of different metabolites such as tannins and different nutritional compounds in food. Lactiplantibacillus plantarum was one the first species to be studied for industrial purposes, and its efficacy to obtaining tannins using fermentation processes. Bacterial fermentation helps to obtain a product with an added value of better quality and without the need to use strong solvents that can reduce their quality and safety. To release tannins, it is necessary to subject the substrate to different conditions to activate the enzyme tannin acyl hydrolase (tannase). The tannase-released compounds can have beneficial effects on health such as antioxidant, anticancer and cardioprotective properties, among others. Therefore, this review analyzes tannase release and other metabolites by fermentation processes.

Purification, Structural Characteristics, and Biological Activities of Exopolysaccharide Isolated From Leuconostoc mesenteroides SN-8

In this study, a novel exopolysaccharide (EPS) was extracted from Leuconostoc mesenteroides Shen Nong's (SN)-8 which can be obtained from Dajiang. After the purification step, EPS-8-2 was obtained with molecular weights of 1.46 × 105 Da. The structural characterization of EPS indicated that the EPS belonged to the class polysaccharide, mainly composed of glucan and also contained certain mannose residues that were found to be connected by α-1,6 glycosidic bonds. Moreover, the results demonstrated that EPS displayed a significant capacity to scavenge free radical to some extent, and this anti-oxidant potential was found to be concentration dependent. The results further revealed that EPS displayed a significant inhibitory potential on the growth of HepG2 cells by promoting apoptosis and induced cell cycle arrest in G1 and G2 phases. Overall, these results suggested that EPS can be explored as a possible anti-cancer agent.

The second messenger c-di-AMP mediates bacterial exopolysaccharide biosynthesis: a review

Cyclic dimeric adenosine 3'-5'-monophosphate (c-di-AMP) is a recently discovered nucleotide messenger in bacteria. It plays an important role in signaling, transcription, and cell physiology, such as in bacterial growth, potassium transport, fatty acid synthesis, the metabolic balance of cell wall components, and biofilm formation. Exopolysaccharides (EPSs) have distinct physico-chemical properties and diverse bioactivities including antibacterial, hypolipidemic, and antioxidative activities, and they are widely used in the food, pharmaceutical, and cosmetic industries. Although c-di-AMP has been demonstrated to regulate the biosynthesis of bacterial EPSs, only a single c-di-AMP receptor, CabpA, has been identified in EPS synthesis. With the aim of describing current understanding of the regulation of microbial EPSs, this review summarizes c-di-AMP biosynthesis and degradation as well as the mechanism through which c-di-AMP regulates bacterial EPSs.

Smart Food Packaging Designed by Nanotechnological and Drug Delivery Approaches

This paper offers a general view of the solutions that are able to confer bioactivity to the packaging materials, especially antimicrobial and antioxidant activity. These properties can be induced by the nature of the polymers blend or due to the addition of ternary components from natural agents (essential oils or other extracts) to synthetic organic and inorganic agents, including nanoparticles with a broad antimicrobial activity such as metals (e.g., Ag, Au, Cu) or metal oxide (e.g., TiO2, ZnO) nanoparticles, and even bacterial cells such as probiotics. Many times, these components are synergistically used, each of them assuring a specific role or potentiating the role of the other components. The antimicrobial activity can be induced due to the applied coatings or due to the whole bulk material. Along with an increasing food stability which means a longer shelf-life some smart packaging can be exploited in order to highlight the freshness of the food. These act as a sensor (usually pH sensitive but also other mechanisms can be exploited such as aggregation/agglomeration of AuNPs leading to color change or even aldehyde-specific reactions such as the Cannizzaro reaction), and thus, consumers can be confident about the freshness of the food, especially perishable food such as seafood or fish.