Properties of Edible Films Made From Anchovy By-Product Proteins and Determination of Optimum Protein and Glycerol Concentration by the TOPSIS Method

Production and characterization of biodegradable bi-layer films from poly(lactic) acid and zein

Recently, packaging industry has turned to biodegradable packaging, and poly(lactic acid) has become the most remarkable polymer. However, the high oxygen permeability of PLA films significantly limits their use. Therefore, this study, it was aimed to improve the oxygen barrier properties of PLA films without adversely affecting the mechanical and water vapor barrier properties. Biodegradable PLA-Zein bi-layer films were produced by changing PLA and zein thickness. Transparent and UV barrier bi-layer films were obtained. Mechanical properties of PLA films were improved by the production of bi-layer films. Water vapor permeability of bi-layer films increased whereas the permeance decreased with zein coating of PLA. Multi-criteria decision hierarchy was used to select the best bi-layer films based on mechanical, permeance, and opacity results. Oxygen barrier properties of PLA film significantly improved by zein coating, and hydrophobicity of PLA film was not affected by zein coating. The crystallization and melting temperatures of films decreased when compared to PLA films, supporting the mechanical results. Homogeneous, non-porous, and smooth film surface was obtained and zein layer was in good compatibility with PLA layer. These results suggest that zein coatings could be used to decrease oxygen permeability of PLA films without negatively affecting other properties.

Sunflower Oilcake as a Potential Source for the Development of Edible Membranes

Sunflower oilcake flour (SFOC) resulting from the cold extraction of oil is a rich source of valuable bio-components that stimulated the development of novel, biodegradable and edible films. The films were prepared by incorporating different concentration of sunflower oilcakes (0.1-0.5 g). The obtained films were characterized in terms of physical, water-affinity, antimicrobial and morphological properties. The edible-film properties were affected significantly by the presence and the level of SFOC added. The water vapor permeability and water vapor transmission rate improved with the amount of SFOC added. However, the solubility, oxygen and grease barrier were slightly lower than control film. SEM analysis revealed a rougher but continuous structure with the increases in sunflower oilcake. Moreover, the films with different SFOC levels were opaque, thus presenting good protection against UV radiation. Overall, the SFOC can be use as raw material to produce edible films with suitable properties and microbiological stability for food-packaging applications.

Effect of anchovy by-product protein coating incorporated with thyme essential oil on the shelf life of anchovy (Engraulis encrasicolus L.) fillets

The effects of anchovy by-product protein coatings incorporated with thyme essential oil (TEO) on the shelf life of anchovy (Engraulis encrasicolus L.) fillets stored at 4 ± 1 °C were investigated. We grouped fillets in three categories: untreated fillets, fillets treated in coating solution alone, and fillets treated in coating solution containing 1.5% TEO and analyzed on 0, 3, 6, and 9 days of storage. It was observed that the total volatile basic nitrogen (TVB-N) and pH of all the fillet groups increased under cold storage conditions; however, this increase was much slow in both the coated anchovy fillets. Both coating applications slowed down the lipid oxidation but the coating containing TEO exhibited better effect than coating alone. The coating application alone or with essential oil had limited effect on microbial growth but positively affected the sensory quality. These results revealed that anchovy by-product protein coating mixed with TEO may prolong anchovy fillets' shelf life stored under cold condition.