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

Abstract

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