On-package indicator films based on natural pigments and polysaccharides for monitoring food quality: a review.

Deterioration of food quality and freshness is mainly due to microbial growth and enzyme activity. Chilled fresh food, especially meat and seafood, as well as pasteurized products, rapidly lose quality and freshness during packing, distribution and storage. Real-time food quality monitoring using on-package indicator films can help consumers make informed purchasing decisions. Interest in the use of intelligent packaging systems for monitoring safety and food quality has increased in recent years. Polysaccharide-based films can be developed into on-package indicator films due to their excellent film-forming properties and biodegradability. Another important component is the use of colorants with visible color changes at various pH levels. Currently, natural pigments are receiving increased attention because of their safety and environmental friendliness. This review highlights the recent findings regarding the role of natural pigments, the effects of incorporating natural pigments and polysaccharides on properties of indicator film, current application and limitations of on-package indicator films based on polysaccharides in some foods, problems and improvement of physical properties and color conversion of indicator film containing natural pigments, and development of polysaccharide-based pH-responsive films. © 2022 Society of Chemical Industry.

Influence of physicochemical properties on the production of alternative healthy gummy jelly from tilapia (Oreochromis niloticus) skin with added Thai rice powder.

We developed a new healthy gummy jelly from tilapia skin-derived gelatine and four rice cultivar powders. The gelatine from the tilapia fish skin was obtained using acid and alkaline extraction. The extracted gelatine comprised 96.77 ± 0.96 % protein and featured a breaking force of 5.21 ± 0.58 g, which indicates high gel strength. The fish gelatine was combined with the rice varieties to produce a gummy jelly with an enhanced nutritional value, and its flavor profile was determined. Gummy jelly products with added black sticky rice powder exhibited the highest protein and carbohydrate contents. The gummy jelly supplemented with rice berry had the highest score, with 90 % acceptance, on a nine-point hedonic scale. Microbiological analysis showed that no microorganisms were detected in any of the samples. These results indicate that fish gelatine and rice powder may be used as nutritive ingredients in sports food to improve athletic performances.

Comparison of the effectiveness of alkaline and enzymatic extraction and the solubility of proteins extracted from carbohydrate-digested rice.

Carbohydrate-digested rice (CDR) residue, the production waste of electrolyte drinks, contains high levels of proteins (approximately 50% of dry matter). Methods for effectively extracting protein from CDR were investigated in this study by comparing alkaline and enzymatic extraction. Alkaline extraction was performed using different concentrations of sodium hydroxide (NaOH). Enzymatic extraction was performed with either commercial Alcalase® or Flavourzyme®. Protein recovery and solubility, and total soluble protein obtained via each method were compared to determine extraction effectiveness. In addition, extraction factors affecting protein recovery were adjusted to determine the optimal conditions for each method. Alcalase provided the maximum protein recovery (30.04%), while less protein recovery was achieved with 0.1 N NaOH (55 °C), 1 N NaOH (55 °C), and Flavourzyme. Although the protein recovery achieved by 0.1 N NaOH (27.43%) was close to that of the Alcalase method, protein solubility by extraction with 0.1 N NaOH was much lower (23.46%) than that achieved via the enzymatic method (100%). Hence, the total soluble protein resulting from Alcalase extraction was higher than that obtained using either of the alkaline methods. Consequently, Alcalase extraction was determined to be the most effective method for extracting protein from CDR.