Fabrication, characterization and antifungal evaluation of polyphenolic extract activated keratin starch coating on infected tomato fruits.

In recent times, the application of protein-based bio-composite edible films in postharvest preservation of food and agricultural products is attracting increased attention due to their biodegradability, eco-friendliness and sustainability. In this study, an avocado pear peel polyphenolic extract enriched keratin-starch composite film was fabricated, characterized and evaluated for antimicrobial activity against fungal infected tomato fruits after 6 days of storage at room (25 ± 2 °C) temperature. The SEM/EDX and FTIR results revealed the successful film formation with high degree of compatibility and homogeneity. Following a 6-day post-coating loss in weight of the coated tomato fruits decreased significantly (p < 0.05) with increasing extract concentration while titratable acidity showed a significant (p < 0.05) increase with increasing extract load. Ascorbic acid and lycopene contents were significantly (p < 0.05) higher in the avocado pear peel polyphenolic extract-loaded films. No significant effect was observed in catechol oxidase activity of the tomato extract across the different treatment groups. In addition, fungal growth inhibition showed a dose dependent increase consistent with avocado pear peel polyphenolic load in coated tomato fruits compared to control. Results obtained in this study showed that polyphenolic activated keratin-starch coating was able to reduce spoilage-induce weight loss as well as conserve the overall quality (including titratable acid levels, lycopene and ascorbic acid contents) of fungal-infected tomato fruit and reduce microbial growth. Therefore polyphenolic activated keratin-starch coating could serve as a sustainable and ecofriendly postharvest preservation method to prolong the shelf life of tomato fruits.

Dextran-induced gastric acid secretion in rats.

Dextran C (M.W. 60,000-70,000) employed as plasma expander in the treatment of hypovolemic shock, and which is known to induce histamine release from rat mast cells was studied for its effect on gastric acid secretion in rats. Dextran at doses even lower than the therapeutic dose in man (8-250 mg/kg) induced significant gastric acid secretion in intact anaesthetized rats. Pretreatment of the animals with 1 mg/kg cimetidine significantly reduced the increase in acid secretion while a higher dose of 10 mg/kg completely abolished the effect. The result thus suggests that dextran-induced gastric acid secretion in rats is mediated through histamine release.