A Green Film-Forming Investigation of the Edible Film Based on Funoran: Preparation, Characterization, and the Investigation of the Plasticizer Effects

Directed preparation of algal oligosaccharides with specific structures by algal polysaccharide degrading enzymes

Seaweed polysaccharides have a wide range of sources and rich content, with various biological activities such as anti-inflammatory, anti-tumor, anticoagulant, and blood pressure lowering. They can be applied in fields such as food, agriculture, and medicine. However, the poor solubility of macromolecular seaweed polysaccharides limits their further application. Reports have shown that some biological activities of seaweed oligosaccharides are more extensive and superior to that of seaweed polysaccharides. Therefore, reducing the degree of polymerization of polysaccharides will be the key to the high value utilization of seaweed polysaccharide resources. There are three main methods for degrading algal polysaccharides into algal oligosaccharides, physical, chemical and enzymatic degradation. Among them, enzymatic degradation has been a hot research topic in recent years. Various types of algal polysaccharide hydrolases and related glycosidases are powerful tools for the preparation of algal oligosaccharides, including α-agarases, β-agaroses, α-neoagarose hydrolases and β-galactosidases that are related to agar, κ-carrageenases, ι-carrageenases and λ-carrageenases that are related to carrageenan, β-porphyranases that are related to porphyran, funoran hydrolases that are related to funoran, alginate lyases that are related to alginate and ulvan lyases related to ulvan. This paper describes the bioactivities of agar oligosaccharide, carrageenan oligosaccharide, porphyran oligosaccharide, funoran oligosaccharide, alginate oligosaccharide and ulvan oligosaccharide and provides a detailed review of the progress of research on the enzymatic preparation of these six oligosaccharides. At the same time, the problems and challenges faced are presented to guide and improve the preparation and application of algal oligosaccharides in the future.

Fabrication and characterization of Karaya gum-based films reinforced with bacterial nanocellulose stabilized valerian root extract Pickering emulsion for lamb meat preservation

A novel biodegradable film was fabricated by incorporating bacterial nanocellulose stabilized valerian root extract (VRE) Pickering emulsion into karaya gum with better antioxidant and antibacterial properties for lamb meat preservation. The valerian root extract Pickering emulsion (VPE) exhibited 98 ± 1.84 % encapsulating efficiency and excellent physical stability with an average particle size of 274.6 nm. The incorporation of VPE-5 into the film matrix increased its elongation at break (EAB), and improved water resistance and barrier properties against oxygen, water vapor, and UV light. Moreover, the antioxidant and anti-bacterial properties against S.aerous and E. coli were also improved based on VPE-5 concentration. The SEM images showed a uniform distribution of VPE-5 while FTIR and XRD revealed its compatibility with karaya gum, which improved its thermal stability. The active films showed a significant preservative effect by reducing the pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable count (TVC) value of lamb meat and maintained its texture and color during the storage period of 9 days at 4 °C. These results demonstrated the inclusion of VPE-5 into Karaya gum was a promising technique and offers a great potential application as a bioactive material in food packaging.

Formulization and characterization of guar gum and almond gum based composite coating and their application for shelf-life extension of okra (Hibiscus esculentus)

The current novel study aims was to development and characterization of gum based (guar gum: almond gum) composite formulations with or without addition of oregano essential oils to extend the shelf life of okra at ambient condition. In this study, the optimized composite of guar gum: almond gum (75:25 V/V) prepared with addition of different concentrations (0.05, 0.1 and 0.15 % (V/V) of oregano essential oils to study their physicochemical, rheological, antimicrobial and particle size & zeta potential distribution. In addition, the effects of prepared edible coatings on shelf-life of okra vegetables were also investigated by assessing their postharvest quality attributes at ambient (23 °C) storage up to 7 days storage. The results revealed, increasing concentration of essential oils in composite coating significantly increased in pH, TSS, particle size, antimicrobial (Apergillus. niger, Escherichia coli, Staphylococcus aureus) activity respectively. Furthermore, the increasing EOs improved viscosity (n) and stability of the coatings matrix. In addition, the applications of guar gum (0.25 %): almond gum (0.5 %) composite ratio (75,25) with oregano essential oils exhibited excellent properties and potential to maintain the postharvest characteristics of okra throughout the storage period. The results of this study revealed that the addition of higher concentration (0.15 %) of essential oils in composite formulation of 75 % guar gum +25 % almond gum (03) showed higher value of pH (5.45), antioxidant activity (20.87 %), particle size (899.1 nm), zeta potential (-8.6 mV), polydispersity index (50.6 %) and higher antimicrobial activity against E.coli (19 mm), S. aureus (29 mm) and A. niger (35 mm) as compared to other formulations. Therefore, the lower composite formulation (01) with lower concentration (0.05 %) of oregano essential oil was found most effective formulation to maintain the shelf life of okra for up to 4 days as compared to other treated and control okra samples at ambient temperature by retarded the weight loss (12.74 %), maintained higher firmness (0.998 N), lower respiration rate (484.32 ml Co2/kg/h) respectively on 7 days of storage. The microbial load in the okra samples treated with different guar gum: almond gum composite showed lower microbial load in terms of total plate count and yeast & mold counts as compared to control samples. Samples treated with O3 coating showed lowest TPC (0.1 × 108 cfu/g) and YMC (6.63 × 106 cfu/g) followed by O2 (0.48 × 108 cfu/g, 7.9 × 106 cfu/g) and O1 (0.78 × 108 cfu/g, 9.45 × 106 cfu/g) respectively on 6rd day of storage, overall results indicated that the application of composite coating with different concentrations of oregano essential oils were effective to maintained postharvest shelf life of okra up to 4 days at ambient condition.

The Extraction and Impact of Essential Oils on Bioactive Films and Food Preservation, with Emphasis on Antioxidant and Antibacterial Activities-A Review

Essential oils, consisting of volatile compounds, are derived from various plant parts and possess antibacterial and antioxidant properties. Certain essential oils are utilized for medicinal purposes and can serve as natural preservatives in food products, replacing synthetic ones. This review describes how essential oils can promote the performance of bioactive films and preserve food through their antioxidant and antibacterial properties. Further, this article emphasizes the antibacterial efficacy of essential oil composite films for food preservation and analyzes their manufacturing processes. These films could be an attractive delivery strategy for improving phenolic stability in foods and the shelf-life of consumable food items. Moreover, this article presents an overview of current knowledge of the extraction of essential oils, their effects on bioactive films and food preservation, as well as the benefits and drawbacks of using them to preserve food products.