Properties of fish gelatin films incorporated with different oils at different thickness investigated. Gelatin films incorporated with all oils resulted in higher elongation at break (EAB) compared to control film, regardless of the oils type (P≤0.05). Increasing the thickness of gelatin films with oils decreased the solubility value (P≤0.05) significantly. However, water vapor permeability (WVP) of gelatin films containing oils increased as the thickness of films increased. FTIR spectra showed that incorporation of different oils into gelatin films gave effect on the molecular organization and intermolecular interaction in films matrix particularly at the wavenumber of Amide-I band and 1739-1744 cm-1. SEM analysis revealed the addition of oils into gelatin films enhanced the roughness of the film surface and cross-section. An appropriate combination of oils at moderate thickness could improve the mechanical and barrier properties of fish gelatin films thus fulfill the application either as coatings or films.
The aim of this study was to evaluate the effect of barrel temperature and flour types on the residence time and physical properties of various flour extrudates. Corn flour, rice flour, corn flour with potato starch (30% w/w, d.b), and rice flour with potato starch (30%w/w, d.b) were extruded at screw speed of 75rpm, feed moisture at 25% (w/w, w.b.), barrel temperature ranging from 80°C to 140°C and die size of 1.88mm. The extrudates were dried at 50°C overnight and further analysed. Results showed that an increase in extruder barrel temperature decreased the residence time of the flours in the extruder (from 4.11-11.32min to 2.24-6.76min), but increased the expansion ratio, rehydration ratio, water absorption index, water solubility index and b value of the extrudate (p≤0.05). The extrudates had the mean residence time and physical properties of rice flour
The objective of the present work was to investigate the effects of alginate coating combined with repetitive pulsed light (RPL) treatment on the enzymatic activity of fresh-cut cantaloupes during chilled storage. Fresh-cut cantaloupes were coated with alginate (1.86%, w/v) followed by RPL treatment (0.9 J/cm2 at every 48 h up to 26 d) during storage. Untreated samples and samples with alginate or RPL alone were used as controls. Enzymatic activities [polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), peroxidase (POD), pectinesterase (PE), polygalacturonase (PG), pectate lyase (PEL), β-galactosidase (β-Gal), α-arabinofuranosidase (α-AF) and cellulase] of fresh-cut cantaloupes were evaluated every 4 d during storage. Neither alginate coating nor RPL treatment has any effect on the activities of PE and PEL of freshcut cantaloupes during storage. The individual treatment or in combination did not increase the PAL, PPO, PG and cellulase activities of fresh-cut cantaloupes throughout the storage. Alginate coating with or without RPL was effective in maintaining low POD activity of freshcut cantaloupes. In addition, treatments using alginate coating or alginate coating+RPL were effective in reducing the β-Gal and α-AF activities of fresh-cut cantaloupes during storage. Overall, alginate without or with RPL was effective in reducing changes of enzymatic activities in fresh-cut cantaloupes during storage.