On the use of carrageenan matrices for the development of antiviral edible coatings of interest in berries

Efficacy of an Edible Coating with Carvacrol and Citral in Frozen Strawberries and Blueberries to Control Foodborne Pathogens

Adding essential oils in an edible coating could be an alternative for the food industry to control foodborne pathogens. In 2014, EFSA published a report highlighting the risk associated with Salmonella spp. and Norovirus in fresh and frozen berries. This study aimed to evaluate the efficacy of an edible coating (RP-7) with carvacrol and citral on reducing the population of Salmonella enterica, Escherichia coli O157:H7, Listeria monocytogenes, and murine Norovirus (MNV-1) in frozen strawberries and blueberries. Before evaluating the efficacy, the best method for applying the coating on fruit was studied. The immersion method was selected, with an optimal drying time of 45 min. After this, the berries were frozen and stored for one, two, three, four, and eight weeks at -18 °C. In strawberries, all bacteria were reduced to below 0.7 log cfu/strawberry in the eighth week, and the MNV-1 infectivity showed a reduction of nearly 2 logarithmic units. In blueberries, S. enterica and E. coli O157:H7 were reduced to 0.8 log cfu/blueberries within a week, and MNV-1 achieved a reduction of 0.8 logarithmic units at the end of the assay. The application of RP-7 affected the studied microorganisms in frozen strawberries and blueberries.

Antiviral Activity of Natural Compounds for Food Safety

Gastroenteritis and hepatitis are the most common illnesses resulting from the consumption of food contaminated with human enteric viruses. Several natural compounds have demonstrated antiviral activity against human enteric viruses, such as human norovirus and hepatitis A virus, while little information is available for hepatitis E virus. Many in-vitro studies have evaluated the efficacy of different natural compounds against human enteric viruses or their surrogates. However, only few studies have investigated their antiviral activity in food applications. Among them, green tea extract, grape seed extract and carrageenans have been extensively investigated as antiviral natural compounds to improve food safety. Indeed, these extracts have been studied as sanitizers on food-contact surfaces, in produce washing solutions, as active fractions in antiviral food-packaging materials, and in edible coatings. The most innovative applications of these antiviral natural extracts include the development of coatings to extend the shelf life of berries or their combination with established food technologies for improved processes. This review summarizes existing knowledge in the underexplored field of natural compounds for enhancing the safety of viral-contaminated foods and underscores the research needs to be covered in the near future.

Physical Properties of Cellulose Derivative-Based Edible Films Elaborated with Liposomes Encapsulating Grape Seed Tannins

Combined use of edible films (EF) with nanoencapsulation systems could be an effective alternative for improving the films' physical properties and maintaining bioactive compounds' stability. This research work focuses on the combined use of EF of cellulose-derived biopolymers enriched with liposomes that encapsulate grape seed tannins and on the subsequent evaluation of the physical properties and wettability. Tannin-containing liposomal suspensions (TLS) showed 570.8 ± 6.0 nm particle size and 99% encapsulation efficiency. In vitro studies showed that the release of tannins from liposomes was slower than that of free tannins, reaching a maximum release of catechin of 0.13 ± 0.01%, epicatechin of 0.57 ± 0.01%, and gallic acid of 3.90 ± 0.001% over a 144 h period. Adding liposomes to biopolymer matrices resulted in significant decrease (p < 0.05) of density, surface tension, tensile strength, elongation percentage, and elastic modulus in comparison to the control, obtaining films with greater flexibility and lower breaking strength. Incorporating TLS into EF formulations resulted in partially wetting the hydrophobic surface, reducing adhesion and cohesion compared to EF without liposomes. Results indicate that the presence of liposomes improves films' physical and wettability properties, causing them to extend and not contract when applied to hydrophobic food surfaces.

Polysaccharide-Based Edible Biopolymer-Based Coatings for Fruit Preservation: A Review

Over the last decades, a significant rise in fruit consumption has been noticed as they contain numerous nutritional components, which has led to the rise in fruit production globally. However, fruits are highly liable to spoilage in nature and remain vulnerable to losses during the storage and preservation stages. Therefore, it is crucial to enhance the storage life and safeness of fruits for the consumers. To keep up the grade and prolong storage duration, various techniques are employed in the food sector. Among these, biopolymer coatings have gained widespread acceptance due to their improved characteristics and ideal substitution for synthetic polymer coatings. As there is concern regarding the safety of the consumers and sustainability, edible coatings have become a selective substitution for nurturing fruit quality and preventing decay. The application of polysaccharide-based edible coatings offers a versatile solution to prevent the passage of moisture, gases, and pathogens, which are considered major threats to fruit deterioration. Different polysaccharide substances such as chitin, pectin, carrageenan, cellulose, starch, etc., are extensively used for preparing edible coatings for a wide array of fruits. The implementation of coatings provides better preservation of the fruits such as mango, strawberry, pineapple, apple, etc. Furthermore, the inclusion of functional ingredients, including polyphenols, natural antioxidants, antimicrobials, and bio-nanomaterials, into the edible coating solution matrix adds to the nutritional, functional, and sensory attributes of the fruits. The blending of essential oil and active agents in polysaccharide-based coatings prevents the growth of food-borne pathogens and enhances the storage life of the pineapple, also improving the preservation of strawberries and mangoes. This paper aims to provide collective data regarding the utilization of polysaccharide-based edible coatings concerning their characteristics and advancements for fruit preservation.

Application of antimicrobial chitosan-Furcellaran-hydrolysate gelatin edible coatings enriched with bioactive peptides in shelf-life extension of pork loin stored at 4 and -20 °C

In this study, the authors investigate the preservative capabilities of edible coatings comprising a blend of chitosan, furcellaran and gelatin hydrolysate enhanced with the bioactive peptides RW4 and LL37. The preservative effects on pork samples stored for 21 days at 4 °C and 6 months at -20 °C were studied, while examining changes in microbiological contamination, pH levels, water activity and sensory attributes. Microbiological analyses reveal the coatings' antimicrobial efficacy against aerobic bacteria, microscopic fungi and yeasts, particularly during the initial storage period, when coated samples exhibit microbial reductions of 0.5-2 log CFU/g compared to the controls. The coatings have no discernible impact on water activity during storage in refrigerated or freezer conditions. Notably, differences in pH development can be observed between the coated and control samples, potentially attributable to the antimicrobial action of the coatings. Sensory analysis allows to highlight the inhibition of deterioration related to sensory attributes through the use of edible coatings. In conclusion, employing bioactive peptide-enriched edible coatings holds promise for extending the shelf-life of perishable foods.

Exploring the diverse applications of Carbohydrate macromolecules in food, pharmaceutical, and environmental technologies

Carbohydrates are a class of macromolecules that has significant potential across several domains, including the organisation of genetic material, provision of structural support, and facilitation of defence mechanisms against invasion. Their molecular diversity enables a vast array of essential functions, such as energy storage, immunological signalling, and the modification of food texture and consistency. Due to their rheological characteristics, solubility, sweetness, hygroscopicity, ability to prevent crystallization, flavour encapsulation, and coating capabilities, carbohydrates are useful in food products. Carbohydrates hold potential for the future of therapeutic development due to their important role in sustained drug release, drug targeting, immune antigens, and adjuvants. Bio-based packaging provides an emerging phase of materials that offer biodegradability and biocompatibility, serving as a substitute for traditional non-biodegradable polymers used as coatings on paper. Blending polyhydroxyalkanoates (PHA) with carbohydrate biopolymers, such as starch, cellulose, polylactic acid, etc., reduces the undesirable qualities of PHA, such as crystallinity and brittleness, and enhances the PHA's properties in addition to minimizing manufacturing costs. Carbohydrate-based biopolymeric nanoparticles are a viable and cost-effective way to boost agricultural yields, which is crucial for the increasing global population. The use of biopolymeric nanoparticles derived from carbohydrates is a potential and economically viable approach to enhance the quality and quantity of agricultural harvests, which is of utmost importance given the developing global population. The carbohydrate biopolymers may play in plant protection against pathogenic fungi by inhibiting spore germination and mycelial growth, may act as effective elicitors inducing the plant immune system to cope with pathogens. Furthermore, they can be utilised as carriers in controlled-release formulations of agrochemicals or other active ingredients, offering an alternative approach to conventional fungicides. It is expected that this review provides an extensive summary of the application of carbohydrates in the realms of food, pharmaceuticals, and environment.

Unraveling the bioactive interplay: seaweed polysaccharide, polyphenol and their gut modulation effect

Seaweed is rich in many unique bioactive compounds such as polyphenols and sulfated polysaccharides that are not found in terrestrial plant. The discovery of numerous biological activities from seaweed has made seaweed an attractive functional food source with the potential to be exploited for human health benefits. During food processing and digestion, cell wall polysaccharide and polyphenols commonly interact, and this may influence the nutritional properties of food. Interactions between cell wall polysaccharide and polyphenols in plant-based system has been extensively studied. However, similar interactions in seaweed have received little attention despite the vast disparity between the structural and chemical composition of plant and seaweed cell wall. This poses a challenge in extracting seaweed bioactive compounds with intact biological properties. This review aims to summarize the cell wall polysaccharide and polyphenols present in brown, red and green seaweed, and current knowledge on their potential interactions. Moreover, this review gives an overview of the gut modulation effect of seaweed polysaccharide and polyphenol.

Vanillin Cross-Linked Chitosan Film with Controlled Release of Green Tea Polyphenols for Active Food Packaging

We report a novel cross-linked chitosan composite film containing vanillin, glycerol, and green tea extract. The effects of vanillin-mediated cross-linking and the incorporation of antimicrobial green tea polyphenols were investigated. The cross-linking effect, confirmed by Fourier transform infrared (FTIR) analysis, increased the tensile strength of the biopolymer film to 20.9 ± 3 MPa. The release kinetics of polyphenols from the chitosan-vanillin matrix was studied, and we reported an initial burst release (8 h) followed by controlled release (8 to 400 h). It was found that both vanillin and green tea polyphenols were successful inhibitors of foodborne bacteria, with a minimum inhibitory concentration of the tea polyphenols determined as 0.15 mg/mL (Staphylococcus aureus). These active components also displayed strong antioxidant capacities, with polyphenols quenching >80% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals at all concentrations tested. Degradation results revealed that there was a significant (>85%) mass loss of all samples after being buried in compost for 12 weeks. The biopolymeric films, prepared by solvent casting methods, adhere to green chemistry and waste valorization principles. The one-pot recipe reported may also be applied to other cross-linkers and active compounds with similar chemical functionalities. Based on the obtained results, the presented material provides a promising starting point for the development of a degradable active packaging material.

Application of ATR-FTIR Incorporated with Multivariate Data Analysis for Discrimination and Quantification of Urea as an Adulterant in UHT Milk

Urea is naturally present in milk, yet urea is added intentionally to increase milk's nitrogen content and shelf life. In this study, a total of 50 Ultra heat treatment (UHT) milk samples were spiked with known urea concentrations (0-5 w/v%). Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy with principal component analysis (PCA), discriminant analysis (DA), and multiple linear regression (MLR) were used for the discrimination and quantification of urea. The PCA was built using 387 variables with higher FL > 0.75 from the first PCA with cumulative variability (90.036%). Subsequently, the DA model was built using the same variables from PCA and demonstrated the good distinction between unadulterated and adulterated milk, with a correct classification rate of 98% for cross-validation. The MLR model used 48 variables with p-value < 0.05 from the DA model and gave R2 values greater than 0.90, with RMSE and MSE below 1 for cross-validation and prediction. The DA and MLR models were then validated externally using a test dataset, which shows 100% correct classification, and the t-test result (p > 0.05) indicated that the MLR could determine the percentage of urea in UHT milk within the permission limit (70 mg/mL). In short, the wavenumbers 1626.63, 1601.98, and 1585.5534 cm-1 are suitable as fingerprint regions for detecting urea in UHT milk.

Edible alginate-based films with anti-SARS-CoV-2 activity

The viability of SARS-CoV-2 on food surfaces and its propagation through the food chain has been discussed by several stakeholders, as it may represent a serious public health problem, bringing new challenges to the food system. This work shows for the first time that edible films can be used against SARS-CoV-2. Sodium alginate-based films containing gallic acid, geraniol, and green tea extract were evaluated in terms of their antiviral activity against SARS-CoV-2. The results showed that all these films have strong in vitro antiviral activity against this virus. However, a higher concentration of the active compound (1.25%) is needed for the film containing gallic acid to achieve similar results to those obtained for lower concentrations of geraniol and green tea extract (0.313%). Furthermore, critical concentrations of the active compounds in the films were used to evaluate their stability during storage. Results showed that gallic acid-loaded films lose their activity from the second week of storage, while films with geraniol and green tea extract only show a drop in activity after four weeks. These results highlight the possibility of using edible films and coatings as antiviral materials on food surfaces or food contact materials, which may help to reduce the spreading of viruses through the food chain.

Recent advances in polysaccharide-based edible coatings for preservation of fruits and vegetables: A review

Harvested fruits and vegetables are prone to decay and quality deterioration during storage. Although traditional packaging and chemical treatments are effective, they are harmful to the environment and human health. Hence, higher requirements for food preservation technology are increasingly proposed. Nontoxic, renewable, degradable, and edible packaging for fruits and vegetables has become a research hotspot in recent years. Chitosan, alginate, cellulose, pectin, starch, and other polysaccharides as coating materials have been widely used. Compared with traditional plastic packaging and chemical treatment, these coatings exhibited a better preservation effect and higher safety. In this paper, the preservation mechanism of fruits and vegetables by edible coatings treatment was described, and the research on edible coatings used in fruits and vegetables was summarized. The effects polysaccharide-based edible coatings on physicochemical quality and antimicrobial effect of fruits and vegetables were reviewed.

Passive antifouling and active self-disinfecting antiviral surfaces

Viruses pose a serious threat to human health and society in general, as virus infections are one of the main causes of morbidity and mortality. Till May 2022, over 513 million people around the world have been confirmed to be infected and more than 6.2 million have died due to SARS-CoV-2. Although the COVID-19 pandemic will be defeated in the near future, we are likely to face new viral threats in the coming years. One of the important instruments to protect from viruses are antiviral surfaces, which are essentially capable of limiting their spread. The formulation of the concept of antiviral surfaces is relatively new. In general, five types of mechanism directed against virus spread can be proposed for antiviral surfaces; involving: direct and indirect actions, receptor inactivation, photothermal effect, and antifouling behavior. All antiviral surfaces can be classified into two main types - passive and active. Passive antiviral surfaces are based on superhydrophobic coatings that are able to repel virus contaminated droplets. In turn, viruses can become biologically inert (e.g., blocked or destroyed) upon contact with active antiviral surfaces, as they contain antiviral agents: metal atoms, synthetic or natural polymers, and small molecules. The functionality of antiviral surfaces can be significantly improved with additional properties, such as temperature- or pH-responsivity, multifunctionality, non-specific action on different virus types, long-term application, high antiviral efficiency and self-cleaning.

Antibacterial, Antifungal and Antiviral Polymeric Food Packaging in Post-COVID-19 Era

Consumers are now more concerned about food safety and hygiene following the COVID-19 pandemic. Antimicrobial packaging has attracted increased interest by reducing contamination of food surfaces to deliver quality and safe food while maintaining shelf life. Active packaging materials to reduce contamination or inhibit viral activity in packaged foods and on packaging surfaces are mostly prepared using solvent casting, but very few materials demonstrate antiviral activity on foods of animal origin, which are important in the human diet. Incorporation of silver nanoparticles, essential oils and natural plant extracts as antimicrobial agents in/on polymeric matrices provides improved antifungal, antibacterial and antiviral properties. This paper reviews recent developments in antifungal, antibacterial and antiviral packaging incorporating natural or synthetic compounds using preparation methods including extrusion, solvent casting and surface modification treatment for surface coating and their applications in several foods (i.e., bakery products, fruits and vegetables, meat and meat products, fish and seafood and milk and dairy foods). Findings showed that antimicrobial material as films, coated films, coating and pouches exhibited efficient antimicrobial activity in vitro but lower activity in real food systems. Antimicrobial activity depends on (i) polar or non-polar food components, (ii) interactions between antimicrobial compounds and the polymer materials and (iii) interactions between environmental conditions and active films (i.e., relative humidity, oxygen and water vapor permeability and temperature) that impact the migration or diffusion of active compounds in foods. Knowledge gained from the plethora of existing studies on antimicrobial polymers can be effectively utilized to develop multifunctional antimicrobial materials that can protect food products and packaging surfaces from SARS-CoV-2 contamination.

Antiviral Biodegradable Food Packaging and Edible Coating Materials in the COVID-19 Era: A Mini-Review

With the onset of the COVID-19 pandemic in late 2019, and the catastrophe faced by the world in 2020, the food industry was one of the most affected industries. On the one hand, the pandemic-induced fear and lockdown in several countries increased the online delivery of food products, resulting in a drastic increase in single-use plastic packaging waste. On the other hand, several reports revealed the spread of the viral infection through food products and packaging. This significantly affected consumer behavior, which directly influenced the market dynamics of the food industry. Still, a complete recovery from this situation seems a while away, and there is a need to focus on a potential solution that can address both of these issues. Several biomaterials that possess antiviral activities, in addition to being natural and biodegradable, are being studied for food packaging applications. However, the research community has been ignorant of this aspect, as the focus has mainly been on antibacterial and antifungal activities for the enhancement of food shelf life. This review aims to cover the different perspectives of antiviral food packaging materials using established technology. It focuses on the basic principles of antiviral activity and its mechanisms. Furthermore, the antiviral activities of several nanomaterials, biopolymers, natural oils and extracts, polyphenolic compounds, etc., are discussed.

Nanocoatings: Universal antiviral surface solution against COVID-19

In the current scenario, there is critical global demand for the protection of daily handling surfaces from the viral contamination to limit the spread of COVID-19 infection. The nanotechnologists and material scientists offer sustainable solutions to develop antiviral surface coatings for various substrates including fabrics, plastics, metal, wood, food stuffs etc. to face current pandemic period. They create or propose antiviral surfaces by coating them with nanomaterials which interact with the spike protein of SARS-CoV-2 to inhibit the viral entry to the host cell. Such nanomaterials involve metal/metal oxide nanoparticles, hierarchical metal/metal oxide nanostructures, electrospun polymer nanofibers, graphene nanosheets, chitosan nanoparticles, curcumin nanoparticles, etched nanostructures etc. The antiviral mechanism involves the repletion (depletion) of the spike glycoprotein that anchors to surfaces by the nanocoating and makes the spike glycoprotein and viral nucleotides inactive. The nature of interaction between the nanomaterial and virus depends on the type nanostructure coating over the surface. It was found that functional coating materials can be developed using nanomaterials as their polymer nanocomposites. The various aspects of antiviral nanocoatings including the mechanism of interaction with the Corona Virus, the different type of nanocoatings developed for various substrates, future research areas, new opportunities and challenges are reviewed in this article.

Past and Current Progress in the Development of Antiviral/Antimicrobial Polymer Coating towards COVID-19 Prevention: A Review

The astonishing outbreak of SARS-CoV-2 coronavirus, known as COVID-19, has attracted numerous research interests, particularly regarding fabricating antimicrobial surface coatings. This initiative is aimed at overcoming and minimizing viral and bacterial transmission to the human. When contaminated droplets from an infected individual land onto common surfaces, SARS-CoV-2 coronavirus is able to survive on various surfaces for up to 9 days. Thus, the possibility of virus transmission increases after touching or being in contact with contaminated surfaces. Herein, we aim to provide overviews of various types of antiviral and antimicrobial coating agents, such as antimicrobial polymer-based coating, metal-based coating, functional nanomaterial, and nanocomposite-based coating. The action mode for each type of antimicrobial agent against pathogens is elaborated. In addition, surface properties of the designed antiviral and antimicrobial polymer coating with their influencing factors are discussed in this review. This paper also exhibits several techniques on surface modification to improve surface properties. Various developed research on the development of antiviral/antimicrobial polymer coating to curb the COVID-19 pandemic are also presented in this review.

Proso-Millet-Starch-Based Edible Films: An Innovative Approach for Food Industries

The present investigation searches for functional and antioxidant properties in proso millet starch and films. Proso millet starch was studied for its physical, chemical, morphological, and antioxidant properties. Furthermore, films were prepared from proso millet starch (native) and a starch–ĸ-carrageenan blend. Both films were characterized for moisture content, thickness, water-solubility, opacity, water vapor permeability, and textural and antioxidant properties. The amylose content, water absorption capacity, swelling, and solubility power of the proso millet starch were 19.19%, 87.5%, 15.32%, and 19%, respectively. Compared to aqueous extracts (0.68 mg GAE/g and 0.36 mg AAE/g), the total phenolics and total antioxidant capacity were observed to be higher in methanolic starch extracts (0.75 mg GAE/g and 0.41 mg AAE/g). Methanol extracts of native starch-based films showed higher antioxidant activity than the film prepared using a ĸ-carrageenan blend. The water vapor permeability and solubility of films prepared from native starch (2.38 g/Pa·s·m2 and 28%) were lower than those prepared using the ĸ-carrageenan blend (3.19 g/Pa·s·m2 and 42.05%). The findings may be of commercial interest to pharmaceutical and food industries in producing new antioxidant-rich drugs and food products.

Green-based active packaging: Opportunities beyond COVID-19, food applications, and perspectives in circular economy-A brief review

The development of biodegradable packaging, based on agro-industrial plant products and by-products, can transform waste into products with high added value and reduce the use of conventional nonrenewable packaging. Green-based active packaging has a variety of compounds such as antimicrobials, antioxidants, aromatics, among others. These compounds interact with packaged products to improve food quality and safety and favor the migration of bioactive compounds from the polymeric matrix to food. The interest in the potential hygienic-sanitary benefit of these packages has been intensified during the COVID-19 pandemic, which made the population more aware of the relevant role of packaging for protection and conservation of food. It is estimated that the pandemic scenario expanded food packaging market due to shift in eating habits and an increase in online purchases. The triad health, sustainability, and circular economy is a trend in the development of packaging. It is necessary to minimize the consumption of natural resources, reduce the use of energy, avoid the generation of waste, and emphasize the creation of social and environmental values. These ideas underpin the transition from the emphasis on the more subjective discourse to the emphasis on the more practical method of thinking about the logic of production and use of sustainable packaging. Presently, we briefly review some trends and economic issues related to biodegradable materials for food packaging; the development and application of bio-based active films; some opportunities beyond COVID-19 for food packaging segment; and perspectives in circular economy.

Antiviral Activity of Carrageenans and Processing Implications

Carrageenan and carrageenan oligosaccharides are red seaweed sulfated carbohydrates with well-known antiviral properties, mainly through the blocking of the viral attachment stage. They also exhibit other interesting biological properties and can be used to prepare different drug delivery systems for controlled administration. The most active forms are λ-, ι-, and κ-carrageenans, the degree and sulfation position being determined in their properties. They can be obtained from sustainable worldwide available resources and the influence of manufacturing on composition, structure, and antiviral properties should be considered. This review presents a survey of the antiviral properties of carrageenan in relation to the processing conditions, particularly those assisted by intensification technologies during the extraction stage, and discusses the possibility of further chemical modifications.

Edible packaging: Sustainable solutions and novel trends in food packaging

Novel food packaging techniques are an important area of research to promote food quality and safety. There is a trend towards environmentally sustainable and edible forms of packaging. Edible packaging typically uses sustainable, biodegradable material that is applied as a consumable wrapping or coating around the food, which generates no waste. Numerous studies have recently investigated the importance of edible materials as an added value to packaged foods. Nanotechnology has emerged as a promising method to provide use of bioactives, antimicrobials, vitamins, antioxidants and nutrients to potentially increase the functionality of edible packaging. It can act as edible dispensers of food ingredients as encapsulants, nanofibers, nanoparticles and nanoemulsions. In this way, edible packaging serves as an active form of packaging. It plays an important role in packaged foods by desirably interacting with the food and providing technological functions such as releasing scavenging compounds (antimicrobials and antioxidants), and removing harmful gasses such as oxygen and water vapour which all can decrease products quality and shelf life. Active packaging can also contribute to maintaining the nutritive profile of packaged foods. In this review, authors present the latest information on new technological advances in edible food packaging, their novel applications and provide examples of recent studies where edible packaging possesses also an active role.

On the Use of Persian Gum for the Development of Antiviral Edible Coatings against Murine Norovirus of Interest in Blueberries

In the last decades, berries have been identified as important vehicles for the transmission of foodborne viruses and different strategies are being explored to eliminate or reduce viral contamination in these fruits. The aim of this work was to develop novel edible coatings with antiviral properties for inactivating and reducing murine norovirus (MNV). Firstly, the effect of gelatin (G) addition on Persian gum (PG) films was studied in terms of microstructural, mechanical, optical, and water barrier properties. The following PG:G ratios were considered: 100:0, 75:25, 50:50, 25:75, and 0:100. Microstructure analysis revealed the compatibility of both hydrocolloids since no phase separation was observed. The addition of G to PG films provided stiffer and more deformable films than pure PG, with lower water vapor permeability values. Specifically, films prepared with 50:50 PG:G ratio presented better mechanical and barrier performance. Interestingly, pure PG showed antiviral activity on murine norovirus, probably due to the presence of some impurities (mainly tannins). Adding allyl isothiocyanate (AITC) enhanced the PG antiviral activity at refrigerated temperatures in blueberries, not being affected by the AITC concentration. This effect was not observed at ambient temperature, probably due to the volatilization of AITC.

Food forensics on gelatine source via ultra-high-performance liquid chromatography diode-array detector and principal component analysis

This study provided a step-by-step procedure to investigate the distribution of 17 amino acids (AAs) in 50 fish, 50 bovine and 54 porcine gelatines using Ultra-High-Performance Liquid Chromatography Diode-Array Detector (UHPLC–DAD) with the incorporation of principal component analysis (PCA). Dataset pre-processing step, including outlier removal, analysis of variance (ANOVA), dataset adequacy test, dataset transformation and correlation test was performed before the PCA. The method rendered linearity range of 37.5–1000 pmol/µL and accuracy of 85–111% recovery. The bovine and porcine gelatines showed a similar ranking while the l-Alanine (Ala), l-Arginine (Arg) and l-Glutamic acid (Glu) concentrations had differed the fish gelatine from the bovine and porcine gelatines. The PCA, which explained 77.013% cumulative variability at eigenvalue of 5.436, showed AAs with strong FL in PC1 had polar and nonpolar side chains while AAs with strong FL in PC2 had polar side chain. The AAs with moderate and weak FL in PC1 had a nonpolar side chain. The AAs with strong FL of in PC1 were also the same AAs with 7, 6 and 5 strong CMs as determined in the correlation test. The second PCA showed that the l-Serine (Ser), Arg, Glycine (Gly), l-Threonine (Thr), l-Methionine (Met), l-Histidine (His) and L-Hydroxyproline (Hyp) were significant in fish gelatine; Hyp, Met, Thr, Ser, His, Gly, and Arg in bovine gelatine; and l-Proline (Pro), l-Tyrosine (Tyr), l-Valine (Val), l-Leucine (Leu), and l-Phenylalanine (Phe) in porcine gelatine. The 100% fish, bovine and porcine gelatines accommodated grouping 1, 2 and 3, respectively, which proved that AAs with strong FL (Hyp, His, Ser, Arg, Gly, Thr, Pro, Tyr, Met, Val, Leu and Phe) were the significant AAs and becomes the biomarkers to identify the gelatine source. From this study, the PCA was a useful tool to analyse a multivariate dataset that could provide an in-depth understanding of AA distributions as compared to ANOVA and correlation test.

Strategies for Microbial Decontamination of Fresh Blueberries and Derived Products

Increasing consumption of blueberries is associated with appreciation of their organoleptic properties together with their multiple health benefits. The increasing number of outbreaks caused by pathogenic microorganisms associated with their consumption in the fresh state and the rapid spoilage of this product which is mainly caused by moulds, has led to the development and evaluation of alternatives that help mitigate this problem. This article presents different strategies ranging from chemical, physical and biological technologies to combined methods applied for microbial decontamination of fresh blueberries and derived products. Sanitizers such as peracetic acid (PAA), ozone (O3), and electrolyzed water (EOW), and physical technologies such as pulsed light (PL) and cold plasma (CP) are potential alternatives to the use of traditional chlorine. Likewise, high hydrostatic pressure (HHP) or pulsed electrical fields (PEF) successfully achieve microbial reductions in derivative products. A combination of methods at moderate intensities or levels is a promising strategy to increase microbial decontamination with a minimal impact on product quality.

Improvement of Andean Blueberries Postharvest Preservation Using Carvacrol/Alginate-Edible Coatings

Edible coatings are attractive strategies for blueberries postharvest preservation. In this work, carvacrol/alginate coatings were developed for application on Andean blueberries. Coating formulations were prepared based on blends of sodium alginate (2% w/v), carvacrol (0%, 0.03%, 0.06% or 0.09%), glycerol, and water and applied to the fruits by dip-coating. Then, the fruits were immersed in a calcium batch to induce a crosslink reaction. Changes in the physicochemical and microbiological characteristics of the blueberries were monitored during 21 days of storage at 4 °C. Coated blueberries were better preserved throughout the 21 days of storage because of their lower respiration rate and water loss, in comparison with the uncoated ones. Besides, the coatings enhanced the appearance and the gloss of the fruits. Control fruits showed a significant decrease in the firmness, while, in the coated fruits, this critical postharvest quality was preserved during the entire storage. Coating formulations with 0.09% of carvacrol was the most effective in preventing mesophilic aerobic bacteria and molds/yeasts growth on the fruits during the storage. Edible carvacrol/alginate coatings can be considered as a useful alternative to complement the benefits of refrigerated storage by delaying post-harvest spoilage of Andean blueberries.

Edible Coating and Pulsed Light to Increase the Shelf Life of Food Products

The application of edible coatings (EC) in combination with pulsed light (PL) treatments represents an emerging approach for extending the shelf life of highly perishable but high value-added products, such as fresh-cut fruits and vegetables. The surface of these products would benefit from the protective effects of ECs and the PL decontamination capability. This review describes in detail the fundamentals of both EC and PL, focusing on the food engineering principles in the formulation and application of EC and the delivery of efficient PL treatments and the technological aspects related to the food characterization following these treatments and discussing the implementation of the two technologies, individually or in combination. The advantages of the combination of EC and PL are extensively discussed emphasizing the potential benefits that may be derived from their combination when preserving perishable foods. The downsides of combining EC and PL are also presented, with specific reference to the potential EC degradation when exposed to PL treatments and the screening effect of PL transmittance through the coating layer. Finally, the potential applications of the combined treatments to food products are highlighted, comparatively presenting the treatment conditions and the product shelf-life improvement.

Alginate-Edible Coatings for Application on Wild Andean Blueberries (Vaccinium meridionale Swartz): Effect of the Addition of Nanofibrils Isolated from Cocoa By-Products

Edible coatings and films are appealing strategies for the postharvest management of blueberries. In the current work, alginate and alginate/cellulose nanofibril (CNF) edible coatings crosslinked with calcium chloride were developed for application on Andean blueberry (a promissory wild blueberry). Cocoa by-products were valorized through the isolation of their CNFs, and these were incorporated in the edible coatings. Edible coating formulations were based on blends of alginate (2% w/v), CNFs (0%, 0.1%, or 0.3%), glycerol, and water. In addition, stand-alone films were prepared, and their light and water vapor barrier properties were studied before applying the coating on the fruit surface. The results show that the addition of CNFs caused a significant decrease in the transparency and the water vapor permeability of the alginate films. After applying on the Andean blueberry fruits, the alginate and alginate/CNF coatings enhanced the appearance and the firmness of the fruits. Moreover, they significantly reduced the respiration rate and the water loss of the Andean blueberries throughout the 21 days of refrigerated storage. Alginate and alginate/CNFs coatings may be considered a useful alternative for the delay of the postharvest deterioration of Andean blueberries.

Rheology of partially and totally oxidized red seaweed galactans

Agarose and κ-carrageenan were oxidized using (2,2,6,6-tetramethylpiperidinyl)oxy (TEMPO) in the presence of NaOCl and NaBr. Products with several degrees of oxidation were structurally characterized. The mechanical spectra were determined: derivatives with a medium to high degree of oxidation give rise to polysaccharides that behave like dilute solutions in water, whereas those with a degree of oxidation close to 20 % keep the gelling properties with a different thermo-rheological response towards pH (6.5 or 4.0) and counterions (K⁺ or Ca²⁺) in comparison with the native polysaccharides. For instance, they showed a marked dependence on the presence of calcium ions, observed in the increase of thermal stability and dynamic elastic component (G') value, due to the known interaction of this divalent cation with the carboxylate groups. In this sense, these derivatives with low oxidation degrees have proven to be not only thermosensitive, like the native polysaccharide, but also pH- and calcium-sensitive.