Structural, Physical, and Antifungal Characterization of Starch Edible Films Added with Nanocomposites and Mexican Oregano (Lippia berlandieri Schauer) Essential Oil

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.

Influence of pomelo pericarp essential oil on the structural characteristics of gelatin-arrowroot tuber flour-based edible films

The present study examined the comprehensive effects of incorporating pomelo pericarp essential oil (PEO) at varying concentrations (0.5, 1.0, 1.5, and 2.0%) into gelatin-arrowroot tuber flour (GEL-ATF) based edible films and evaluated the influence on various structural properties. ATF was prepared from Maranta arundinacea L. tubers using a carefully controlled method to ensure its quality and suitability as a polysaccharide base in film formulations. The results indicated that adding PEO to the GEL-ATF films decreased L, a, and b color values and increased opacity values, especially at higher PEO concentrations. Furthermore, the appearance of both GEL-ATF and GEL-ATF-PEO films exhibited similar characteristics. Incorporating PEO significantly reduced moisture content and water vapor permeability (WVP), indicating enhanced barrier properties against moisture. Additionally, an increase in PEO concentration resulted in decreased film solubility. A decrease in tensile strength (TS) but an increase in elongation at break (EAB) was observed in the GEL-ATF films with higher PEO concentrations (>1% PEO). Slight variations in thermal degradation patterns with increased PEO addition in GEL-ATF were noticed, while X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR) results of the tested films provided insights into structural and chemical modifications, indicating changes in crystallinity and molecular interactions upon increased PEO concentration in the film compositions. The microstructural observations confirmed that PEO incorporation led to smoother film surfaces, suggesting a more uniform matrix, which could enhance the film's barrier and mechanical properties. Furthermore, applying PEO into GLE-ATF films exhibited strong antimicrobial activity against Bacillus cereus ATCC 11778. Overall, the present study found that the higher PEO (>1%) concentrations significantly influenced the physical and mechanical properties of GEL-ATF-based edible films. This newly developed edible film could be an effective alternative to inedible polymers for sustainable food packaging solutions.

Evaluation of Pretreatments and Extraction Conditions on the Antifungal and Antioxidant Effects of Garlic (Allium sativum) Peel Extracts

This study aimed to evaluate the effect of pretreatments and extraction conditions on the antioxidant and antifungal characteristics of garlic peel extracts. The effect of pretreatments (fermentation and steam cooking) on the yield, antifungal (Colletotrichum gloeosporioides and Botrytis cinerea), and antioxidant (total phenolic compounds, total flavonoids, and antioxidant capacity) properties of garlic peel extracts were evaluated. A selected pretreatment was applied to evaluate the extraction conditions (solvent, solvent concentration, temperature, and time) on the antifungal activity of garlic peel extracts. At last, garlic peel extracts obtained under specific conditions was applied to papaya and strawberry fruits as preventive and curative treatments against Colletotrichum gloeosporioides and Botrytis cinerea, respectively. Steam cooking pretreatment significantly increased the antifungal and antioxidant capacities of garlic peel extracts compared to the fermentation process. Garlic peel extracts obtained with methanol (60%) for 18 h (25 °C) showed the highest antifungal activity against both microorganisms assessed (57.57% and 75.76% for B. cinerea and C. gloeosporioides, respectively,) on in vitro assays. Moreover, in vivo results indicated that preventive treatment significantly reduced rot disease in papaya (88.95%) and strawberry (54.13%) fruits. Although more studies about the antifungal mechanisms of garlic peel extracts are needed, these results indicated that garlic peel extracts could be used as an antifungal agent.

Óleo essencial nanoformulado de alecrim pimenta (Lippia sidoides) como aditivo em silagens consorciadas

Resumo A presença de microrganismos deterioradores na forragem interfere no processo fermentativo da silagem, devido a competição com as bactérias ácido láticas por substrato, gerando perdas e influenciando o valor nutritivo do material ensilado. Assim, objetiva-se avaliar o efeito do óleo essencial de Alecrim pimenta (Lippia sidoides) e do timol nanoformulado sobre perfil microbiológico, fermentativo e estabilidade aeróbia de silagem do consórcio de Sorgo (Sorghum bicolor var. Ponta Negra) com capim Paiaguás (Urochloa brizantha cv. Paiaguás). Foi adotado esquema fatorial 4 x 3, quatro aditivos aplicados nas silagens (tratamento controle; óleo essencial de Alecrim pimenta nanoformulado (OEN); timol nanoformulado 62%; e timol nanoformulado 100% de pureza), associados a três tempos de abertura do silo (15, 30 e 45 dias), com cinco repetições por tratamento, totalizando 60 mini silos. A população de Clostridium foi maior no tratamento controle e no OEN. A população de Lactobacillus reduziu com o aumento no tempo de abertura do silo. Maiores estabilidades aeróbica foram registradas em silagens com timol nanoformulado 100% com abertura aos 15 dias; e silagens com Timol nanoformulado 62% (tempos de abertura aos 30 e 45 dias). Silagens com timol 100% proporcionaram maiores perdas de matéria seca, gases e efluentes, enquanto que o uso de OEN proporcionou menores perdas de matéria seca e gases. Silos com abertura aos 45 dias apresentaram maiores perdas de matéria seca, gases e efluentes. Silagens de Sorgo e capim Paiaguás que recebram timol nanoformulado foram mais eficientes em controlar as populações de Clostridium e Lactobacillus, bem como este aditivo melhorou a estabilidade aeróbica da silagem.

‘Alecrim Pimenta’ nanoformulated essential oil (Lippia sidoides) as additive in consortium silages

Abstract The presence of spoilage microorganisms in forage interferes with the fermentation process of silage, due to competition with lactic acid bacteria for substrate, generating losses and influencing the nutritional value of the ensiled material. Thus, the objective is to evaluate the effect of “Alecrim Pimenta” essential oil (Lippia sidoides) and nanoformulated thymol on microbiological, fermentative and aerobic stability profile of sorghum (Sorghum bicolor cv. BRS Ponta Negra) silage intercropped with Paiaguás grass (Urochloa brizantha cv. BRS Paiaguás). A 4 x 3 factorial design was adopted, with four additives applied to the silages (control treatment; nanoformulated "Alecrim Pimenta" essential oil (OEN); 62% nanoformulated thymol; and 100% pure nanoformulated thymol), associated with three silo period times (15, 30 and 45 days), with five replications per treatment, totaling 60 mini silos. The Clostridium population was higher in the control treatment and in the OEN. The Lactobacillus population decreased with the increase in silo opening time. Higher aerobic stabilities were recorded in silages with 100% nanoformulated thymol with opening at 15 days; and silages with 62% nanoformulated Thymol (opening period at 30 and 45 days). Silages with 100% thymol provided higher losses of dry matter, gases and effluents, while the use of OEN provided lower losses of dry matter and gases. Silos opened at 45 days showed higher losses of dry matter, gases and effluents. Sorghum and Paiaguás grass silages that received nanoformulated thymol were more efficient in controlling Clostridium and Lactobacillus populations, and this additive improved the aerobic stability of the silage.

Active Antioxidant Packaging from Essential Oils Incorporated Polylactic Acid/Poly(butylene adipate-co-terephthalate)/Thermoplastic Starch for Preserving Straw Mushroom

The short-term shelf life of straw mushrooms (Volvariella volvacea) is a major challenge, hampering their wide distribution. Thus, the aim of this work was to develop a novel active packaging composed of essential oils (EOs), particularly clove oil (CO) and peppermint oil (PO), to reduce autolysis of straw mushrooms. The morphological characterizations, mechanical properties, barrier properties, and antioxidant activities of the films were characterized. The suppressive effects of the EOs on straw mushroom autolysis were estimated during storage at 16 ± 1 °C for 96 h. The results indicated that the addition of EOs weakened the mechanical and barrier properties of the films. The radical-scavenging activities of polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch-peppermint oil (PLA/PBAT/TPS-PO) and polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch-clove oil (PLA/PBAT/TPS-CO) films for 2,2-diphenyl-1-picrylhydrazyl were 56.0% and 91.3%, respectively. However, the PLA/PBAT/TPS-PO film was more effective in reducing polyphenol oxidase activity and maintaining the total phenol content of straw mushrooms, demonstrating better antioxidative activity. Mushrooms packaged with the PLA/PBAT/TPS-PO film exhibited the lowest autolysis rate (42.29%, p < 0.05) after 96 h of storage. Thus, PO is a good preservative agent for straw mushroom.

Investigation of physicochemical properties, antimicrobial and antioxidant activity of edible films based on chitosan/casein containing Origanum vulgare L. essential oil and its effect on quality maintenance of cherry tomato

Edible coatings prevent physicochemical and biological food deterioration. Using bioactive compounds like essential oils can enrich films. In this study, edible films from chitosan (C), casein (Z) and oregano (OEO) were developed, and their physicochemical, barrier, antimicrobial, antioxidant, and structural properties (FTIR, SEM) were investigated. The C₁Z₃ ratio had good mechanical and inhibitory properties, and OEO improves flexibility, barrier, hydrophobic, antimicrobial, and antioxidant properties. The physicochemical and microbiological properties of cherry tomatoes were affected by C₁Z₃ and C₁Z₃O_1.5 coatings. Coated fruits were stored at 4 °C for 32 days. The best results for weight loss, shrinkage, and titratable acidity were found to be 17.88%, 31.12%, and 0.15% in C₁Z₃O_1.5 coated cherry tomatoes, respectively.The TMAB of C₁Z₃O_1.5 coated fruits was less than detectable and the fungal growth was inhibited for 28 days. Accordingly, by adding OEO to chitosan/casein coatings, the spoilage process of cherry tomatoes was delayed for long-term storage.

Characterization of Sodium Alginate-Locust Bean Gum Films Reinforced with Daphnetin Emulsions for the Development of Active Packaging

In this study, we characterized an active film made of sodium alginate (SA)—locust bean gum (LBG) containing daphnetin-based film. Physicochemical characteristics, as well as antioxidant and antibacterial properties, were investigated. The results showed that the addition of a low concentration of daphnetin increased the flexibility of SA–LBG cling film, leading to an improvement in elongation at break and tensile strength. As the daphnetin content increased, solubility, brightness and transparency of the cling film decreased, and the moisture permeability increased. The antioxidant capacity and antibacterial activity of films with daphnetin were improved compared to those of the basal film. In addition, the cling film formed by adsorption had higher bacterial (Shewanella putrefaciens and Pseudomonas fluorescens) inhibition and antioxidant activity rates than direct film formation. The results indicate that the combination of daphnetin in SA–LBG film provides an active film with antioxidant and antibacterial properties, with potential for the development of food-grade packaging material.

Antifungal Polymeric Materials and Nanocomposites

Rising global populations due to medicinal advancements increases the patient population susceptible to superficial and severe fungal infections. Fungi often implicated in these diseases includes the dermatophytes (Microsporum spp., Epidermophtyon spp., Trichophyton spp.) as well as species of the Candida spp., Aspergillosis spp. and Cryptococcus spp. genera. In addition, increasing global populations leads to increasing agricultural demands. Thus, fungal infections of preharvested crops and stored food by plant pathogens such as Magnaporthe oryzae and Fusarium oxysporum can have detrimental socioeconomic effects due to food insecurity. Current antifungal strategies are based mainly on small molecule antifungal drugs. However, these drugs are limited by poor solubility and bioavailability. Furthermore, antifungal resistance against these drugs are on the rise. Thus, antimicrobial polymers offer an alternative antifungal strategy. Antifungal polymers are characterised by cationic and hydrophobic regions where the cationic regions have been shown to interact with microbial phospholipids and membranes. These polymers can be synthetic or natural and demonstrate distinct antifungal mechanisms ranging from fungal cell membrane permeabilisation, cell membrane depolarisation or cell entry. Although the relative importance of such mechanisms is difficult to decipher. Due to the chemical properties of these polymers, they can be combined with other antimicrobial compounds including existing antifungal drugs, charcoals, lipids and metal ions to elicit synergistic effects. In some cases, antifungal polymers and nanocomposites show better antifungal effects or reduced toxicity compared to the widely used small molecule antifungal drugs. This review provides an overview of antimicrobial polymers and nanocomposites with antifungal activity and the current understanding of their antifungal mechanisms.

Prospects of Polymeric Nanofibers Loaded with Essential Oils for Biomedical and Food-Packaging Applications

Essential oils prevent superbug formation, which is mainly caused by the continuous use of synthetic drugs. This is a significant threat to health, the environment, and food safety. Plant extracts in the form of essential oils are good enough to destroy pests and fight bacterial infections in animals and humans. In this review article, different essential oils containing polymeric nanofibers fabricated by electrospinning are reviewed. These nanofibers containing essential oils have shown applications in biomedical applications and as food-packaging materials. This approach of delivering essential oils in nanoformulations has attracted considerable attention in the scientific community due to its low price, a considerable ratio of surface area to volume, versatility, and high yield. It is observed that the resulting nanofibers possess antimicrobial, anti-inflammatory, and antioxidant properties. Therefore, they can reduce the use of toxic synthetic drugs that are utilized in the cosmetics, medicine, and food industries. These nanofibers increase barrier properties against light, oxygen, and heat, thereby protecting and preserving the food from oxidative damage. Moreover, the nanofibers discussed are introduced with naturally derived chemical compounds in a controlled manner, which simultaneously prevents their degradation. The nanofibers loaded with different essential oils demonstrate an ability to increase the shelf-life of various food products while using them as active packaging materials.

Effect of Sonication on the Properties of Flaxseed Gum Films Incorporated with Carvacrol

Carvacrol is a natural compound known to be a highly effective antibacterial; however, it is a hydrophobic molecule, which is a limitation to its use within food packaging. Flaxseed gum (FG) films containing different contents of carvacrol (C) were produced by a film-casting method with sonication. The effects of sonication power and time on the properties of the FG-C films were investigated by measuring the film thickness, mechanical properties, contact angle, opacity, water vapor permeability (WVP), water sorption isotherm, Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry (DSC), antibacterial and antioxidant activities, and microstructure. The results showed that sonication power and time had significant effects on mechanical and barrier properties, film opacity, and degradability (p < 0.05). The tensile strength (TS) and elongation at break (EB) values exhibited an obvious improvement after sonication, and FG-0.5C-6030 had the lowest TS (33.40 MPa) and EB (4.46%) values. FG-C films formed a denser structure and the contact angle was improved as a result of sonication, which improved the integration of carvacrol into the FG matrix. In terms of microstructure, sonication resulted in a homogeneous and continuous crosssection of FG-C films, and regular surface and cross-sectional images were obtained through the highest acoustic intensity and longest time treatment. The FG films incorporated with carvacrol displayed antibacterial properties against Staphylococcus aureus, Vibrio parahaemolyticus, Shewanella putrefaciens, and Pseudomonas fluorescens, as well as increased antioxidant properties, and sonication was proven to enhance both of them.

Antimicrobial Carvacrol Incorporated in Flaxseed Gum-Sodium Alginate Active Films to Improve the Quality Attributes of Chinese Sea bass (Lateolabrax maculatus) during Cold Storage

The objective of this research was to explore the antimicrobial activity and mechanism of carvacrol against Vibrio Parahemolyticus, Shewanella putrefaciens, Staphylococcus aureus and Pseudomonas fluorescens and evaluate the effect of the addition of carvacrol/β-cyclodextrin emulsions to flaxseed gum (FSG)-sodium alginate (SA) edible films on the preservation of Chinese sea bass (Lateolabrax maculatus) fillets during refrigerated storage. The minimum inhibitory concentration (MIC) of carvacrol against V. parahemolyticus, S. putrefaciens, S. aureus and P. fluorescens were 0.5, 0.5, 0.125, and 0.5 mg/mL, respectively. Alkaline phosphatase activity assay, nucleotide and protein leakage, and scanning electron microscope demonstrated that carvacrol damaged the external structure of the tested bacterial cells causing leakage of cytoplasmic components. At the same time, when FSG-SA films containing carvacrol used as coating agents for Chinese sea bass fillets cold storage, FSG-SA films containing 1.0 or 2.0 mg/mL carvacrol could significantly reduce TVB-N content, K-value, the degree of microbial deterioration and maintain quality of sea bass fillets according to organoleptic evaluation results.

Influence of Nano Titanium Dioxide and Clove Oil on Chitosan-Starch Film Characteristics

The combined effects of nano titanium dioxide (TiO₂-N) and clove oil (CO) on the physico-chemical, biological and structural properties of chitosan (CH)/starch (ST) films were investigated by using a solvent casting method. Results indicated that the incorporation of TiO₂-N could improve the compactness of the film, increase the tensile strength (TS) and antioxidant activity, and decrease the water vapour permeability (WVP). As may be expected, the incorporation of CO into the film matrix decreased TS but increased the hydrophobicity as well as water vapour barrier antimicrobial and antioxidant properties. Fourier-transform infrared spectroscopy (FTIR) data supported intermolecular interactions between TiO₂-N, CO and the film matrix. Use of a scanning electron microscope (SEM) showed that TiO₂-N and CO were well dispersed and emulsified in the film network. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves demonstrated that TiO₂-N and CO were well embedded in the film matrix, hence this blend film system could provide new formulation options for food packaging materials in the future.