Development and optimization of processing techniques for intermediate moisture muskmelon chunks

Green tea polyphenols improved the physicochemical stability of mango powder during storage

In this study, the physiochemical characters including moisture content variation, pH, total soluble solids (TSS), color, ascorbic acid content, total polyphenols, and antioxidant activities of mango powder fortified with green tea polyphenols (GTP) were investigated during storage for 90 d. Our results indicated stable colors of mango powder were found after GTP addition. GTP also inhibited the destruction of ascorbic acid during processing, and decreased its degradation rate during the whole storage. The total polyphenols of mango powder stored at 4 ℃ and room temperature decreased by 37.85% and 51.79%, respectively. After addition with GTP, the total polyphenols decreased only by 7.89%, and 13.31%, respectively. The antioxidant activities rose by 1.6 to 4.6-fold after GTP addition, and it decreased at a slower rate compared to that of unfortified mango powder. Correlation analysis indicated that EGCG might be the main substance that retain the physiochemical stability of mango powder.

Variation in physico-chemical, organoleptic and microbial qualities of intermediate moisture pineapple (Ananas comosus (L.) Merr.) slices during storage

Abstract

Pineapple is a commercial tropical fruit ranking sixth in global fruit production. Seasonal market gluts result in huge postharvest losses in all pineapple-growing nations. To reduce postharvest losses of fruits, viable, cost-effective and market-oriented value-added products are needed urgently. The present study was carried out to determine the suitability of two commercial varieties, Kew and Mauritius, for the development of intermediate moisture (IM) fruits and to evaluate product quality during storage. Pineapple slices were steam blanched for 2 min, followed by immersion in osmotic solution containing sucrose and sorbitol (fruit: solution ratio of 1:4), in combination with 0.5% ascorbic acid and 0.25% potassium metabisulfite, for 6 h and were subsequently dehydrated in a tray drier at 50 °C until the moisture content of the product attained equilibrium. The initial moisture contents of IM Kew and Mauritius pineapple slices were 26.53 and 21.65 g/100 g, respectively, while the water activity ranged between 0.671 and 0.666. The L* and b* values showed a decreasing trend, while a* value increased throughout storage, irrespective of variety and storage conditions. The initial TSS of IM pineapple from both varieties was 72 0 Brix, which declined during storage. Though titratable acidity of the product decreased during storage, the decline was insignificant. The total carotenoids of the product from Mauritius was significantly higher (0.809 mg 100 g− 1) compared to the one from Kew (0.215 mg 100 g− 1). Total phenolics contents in IM slices showed an increasing trend during storage, irrespective of varieties and storage conditions. IM pineapple slices from the variety Mauritius had significantly higher flavonoids (40.50 mg) than the product from Kew (30.0 mg 100 g− 1). DPPH radical scavenging activity was highest (3.0 μl ml− 1) in IM slices from the variety Mauritius as compared to those from Kew (5.0 μl ml− 1). IM pineapple from Mauritius recorded higher organoleptic scores throughout storage. Fungi were not detected in any of the samples throughout the storage period while the population of bacteria and yeast was negligible.

Graphical abstract