Packaging films based on biopolymers from seafood processing wastes: Preparation, properties, and their applications for shelf-life extension of seafoods-A comprehensive review.

Biopolymers derived from seafood processing byproducts are used to prepare active and biodegradable films as the packaging of food products. These films possess bioactivities to enhance the shelf life of packed foods by proactively releasing antimicrobial/antioxidative agents into the foods and providing sufficient barrier properties. Seafood processing byproducts are an eminent source of valuable compounds, including biopolymers and bioactive compounds. These biopolymers, including collagen, gelatin, chitosan, and muscle proteins, could be used to prepare robust and sustainable food packaging with some antimicrobial agents or antioxidants, for example, plant extracts rich in polyphenols or essential oils. These active packaging are not only biodegradable but also prevent the deterioration of packed foods caused by spoilage microorganisms as well as chemical deterioration. Seafood discards have a promising benefit for the development of environmentally friendly food packaging systems via the appropriate preparation methods or techniques. Therefore, the green packaging from seafood leftover can be better exploited and replace the synthetic counterpart.

Polylactic Acid Film Coated with Electrospun Gelatin/Chitosan Nanofibers Containing Betel Leaf Ethanolic Extract: Properties, Bioactivities, and Use for Shelf-Life Extension of Tilapia Slices.

Gelatin/chitosan solutions incorporated with betel leaf ethanolic extract (BLEE) at varying concentrations were electrospun on polylactic acid (PLA) films. Nanofibers with different morphologies, as indicated by scanning electron microscopy (SEM), were formed after solutions of gelatin/chitosan with and without BLEE were electrospun on PLA films at a constant voltage (25 kV) and a feed rate of 0.4 mL/h. Beaded gelatin/chitosan nanofibers (GC/NF) were found, particularly when high concentrations of BLEE were encapsulated. PLA films coated with GC/NF, and with BLEE added, showed antioxidant and antibacterial activities, which were augmented by increasing BLEE concentrations. Lower water vapor permeability and enhanced mechanical properties were achieved for GC/NF-coated PLA film (p < 0.05). Microbial growth and lipid oxidation of Nile tilapia slices packaged in PLA film coated with GC/NF containing 2% BLEE were more retarded than those packaged in low-density polyethylene (LDPE) bags over refrigerated storage of 12 days. Based on microbial limits, the shelf-life was escalated to 9 days, while the control had a shelf-life of 3 days. Therefore, such a novel film/bag could be a promising active packaging for foods.

Liposomes loaded with betel leaf (Piper betle L.) ethanolic extract prepared by thin film hydration and ethanol injection methods: Characteristics and antioxidant activities.

Betel leaf ethanolic extract (BLEE), which was dechlorophyllized by sedimentation process was loaded in liposomes at 1 and 2% (w/v) concentrations using two different methods, namely thin film hydration (TF) and ethanol injection (EI) methods. Liposomes loaded with 1% BLEE and prepared by TF method (BLEE/L-T1) had the smallest particle size and paler color than BLEE/L-E1, BLEE/L-E2, and BLEE/L-T2 (p < .05). BLEE/L-T1 also showed strong stability as judged by its lowest zeta potential and polydispersity index. The highest encapsulation efficiency (EE) and lowest releasing efficiency (RE) were also found with BLEE/L-T1. No significant difference (p > .05) in the antioxidant activities was detected between the BLEE-loaded liposomes and BLEE solutions, indicating that encapsulation had no adverse effect on BLEE antioxidant potency. BLEE/L-T1 showed higher antioxidant stability than unencapsulated BLEE at the equivalent amount based on EE (BLEE/U-T1) during in vitro gastrointestinal tract digestion system. Therefore, BLEE/L-T1 could be an efficient delivery system for improving stability of antioxidant activities of BLEE. PRACTICAL APPLICATIONS: Despite the many benefits of betel leaf ethanolic extract, it still has some distinctive odor and slightly greenish color as well as instability induced by environment factors, which can limit applications in foods. Encapsulation of the betel extract in liposomes can be a good approach to mask its undesirable color and odor and to augment its antioxidant stability. Liposomal technology can be used to load betel leaf extract. However, different methods have been implemented to prepare liposomes that exhibit varying encapsulation efficacy as well as bioactivities. Thin film hydration method was shown to yield the liposome with better physical characteristics, higher encapsulation efficiency, slower release, and higher antioxidant stability than the ethanol injection method. Therefore, the thin film hydration method could be adopted to prepare stable liposomes loaded with betel leaf extract that possess antioxidant activity suitable for food applications.

Emulsion stability and properties of fish gelatin-based films as affected by palm oil and surfactants.

BACKGROUND: Gelatin films exhibit the poor water vapour barrier properties. The use of palm oil, which is abundant and available in Thailand, can be a means to lower water vapour migration. To disperse oil in film-forming dispersion (FFD), a surfactant along with appropriate homogenization is required. The study aimed to investigate the influence of palm oil level and surfactants in the absence or presence of glycerol on characteristics of FFD and resulting gelatin films. RESULTS: Similar oil droplet sizes, both d32 and d43 values, of FFD containing soy lecithin were observed, regardless of palm oil level used (P > 0.05). FFD with Tween-20 had larger droplet size as the levels of oil increased (P < 0.05). After 12 h storage, slight increases in d32 and d43 were noticeable in all FFD samples. When the films were determined, lower water vapour permeability (WVP) and tensile strength (TS) but higher elongation at break (EAB) were obtained as palm oil level increased (P < 0.05), regardless of glycerol and surfactant used. Films without glycerol had lower WVP and EAB with higher TS than those containing 300 g kg(-1) glycerol (P < 0.05). No differences in WVP and mechanical properties were found between films containing both surfactants (P > 0.05). CONCLUSION: FFD containing 500 or 750 g kg(-1) palm oil using soy lecithin as a surfactant in the presence of 300 g kg(-1) glycerol had the enhanced homogeneity and stability of oil droplets. The resulting gelatin film had the improved water vapour barrier properties. © 2015 Society of Chemical Industry.

Properties and antioxidant activity of fish skin gelatin film incorporated with citrus essential oils.

Properties of protein-based film from fish skin gelatin incorporated with different citrus essential oils, including bergamot, kaffir lime, lemon and lime (50% based on protein) in the presence of 20% and 30% glycerol were investigated. Films containing 20% glycerol had higher tensile strength (TS) but lower elongation at break (EAB), compared with those prepared with 30% glycerol, regardless of essential oils incorporated (p<0.05). Films incorporated with essential oils, especially from lime, at both glycerol levels showed the lower TS but higher EAB than the control films (without incorporated essential oil) (p<0.05). Water vapour permeability (WVP) of films containing essential oils was lower than that of control films for both glycerol levels (p<0.05). Films with essential oils had varying ΔE(*) (total colour difference), where the highest value was observed in that added with bergamot essential oil (p<0.05). Higher glycerol content increased EAB and WVP but decreased TS of films. Fourier transforms infrared (FTIR) spectra indicated that films added with essential oils exhibited higher hydrophobicity with higher amplitude at wavenumber of 2874-2926 cm(-1) and 1731-1742 cm(-1) than control film. Film incorporated with essential oils exhibited slightly lower thermal degradation resistance, compared to the control film. Varying effect of essential oil on thermal degradation temperature and weight loss was noticeable, but all films prepared using 20% glycerol had higher thermal degradation temperature with lower weight loss, compared with those containing 30% glycerol. Films added with all types of essential oils had rough cross-section, compared with control films, irrespective of glycerol levels. However, smooth surface was observed in all film samples. Film incorporated with lemon essential oil showed the highest ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) (p<0.05), while the other films had lower activity. Thus, the incorporation of different essential oils and glycerol levels directly affected the properties of gelatin-based film from fish skin.

Properties and microstructure of protein-based film from round scad (Decapterus maruadsi) muscle as affected by palm oil and chitosan incorporation.

The properties of protein-based film prepared from round scad (Decapterus maruadsi) muscle in the absence and the presence of palm oil and/or chitosan were investigated. Films added with 25% palm oil (as glycerol substitiution) had the slight decrease in water vapor permeability (WVP) and elongation at break (EAB) (p<0.05). WVP and tensile strength (TS) of films increased but EAB decreased when 10-40% chitosan (as protein substitution) was incorporated (p<0.05). Hydrophobic interactions and hydrogen bonds, together with disulfide and non-disulfide covalent bonds, played an important role in stabilizing the film matrix. The a* and b*-values increased with increasing chitosan levels (p<0.05). Films added with chitosan were less transparent and had the lowered transmission in the visible range. The incorporation of 25% palm oil and 40% chitosan yielded the films with the improved TS but decreased water vapor barrier property. Apart from film strengthening effect, chitosan inconjunction with Tween-20 most likely functioned as the emulsifier/stabilizer in film forming solution containing palm oil.