Physicochemical and Microbiological Changes in Non-Sulfitted Dried Apricots as Affected by Storage Condition

Abstract

The present study was conducted for the determination of physicochemical and microbial quality changes for the non-sulfited sun dried apricots (NSDAs) with three various moisture contents (MCs); 137 g/kg (MC137), 235 g/kg (MC235), and 270 g/kg (MC270); at different temperatures (4, 10, 20, and 30°C) during 12 months in bulk and packaged storage. NSDAs were subjected to physical (moisture, water activity, pH and reflectance color values), chemical (browning formation, β-carotene, and acidity), and microbial (counts for total aerobic mesophilic and psycrofilic bacteria, yeast and mould, xerofilic mould and yeast, osmophilic yeast, lactic acid bacteri, Enterobacteriaceae, Staphylococcus-Micrococcus spp.) analyses at one-month intervals. Results indicated that the fastest brown colour formation occurred in the samples containing 235 g/kg MC at 30°C, and the browning was decelerated below 10°C. No significant change in β-carotene contents of NSDAs during storage was observed (P> 0.05). After rehydration, osmophilic yeast count of NSDAs increased by 2.5 log colony-forming units (cfu/g). Significant reductions were observed in the microbial loads of MC235, and MC270 samples with the decreasing water activity (P<0.05) and increasing storage temperatures. However, yeasts and moulds counts exceeded 5.0 log cfu/g of the samples containing 270 g/kg MC after 2 month of storage at 20°C. Overall, the results of the study suggest that NSDAs should not be stored above 10°C, and the MC should be kept below 235 g/kg to maintain microbial and physicochemical quality.