African Star Apple Juice Stored at Tropical Ambient and Refrigeration Temperatures: Effect on Physicochemical Characteristics, Antioxidant Properties and Microbiological Quality

Abstract

The present study was aimed at evaluating the physicochemical and antioxidant properties as well as microbiological quality of extracted juice from African star apple (Chrysophyllum albidum) stored under tropical ambient and refrigeration conditions. Juice was extracted from mashed star apple fruit cotyledons (after deseeding) and pasteurized in a water bath at 71.2 ^oC for 30 minutes before storage for four (4) weeks under tropical ambient (28±2 ^oC) and refrigeration (6±2 ^oC) conditions. The results showed that there was no fibre in the juice, the moisture was 78.51% and 79.13% for fresh African star apple (ASA) juice and sample stored under ambient conditions, respectively. It also showed pH of ASA juice at week 0 to be 3.52 and week 4 for both samples stored at refrigeration and ambient temperatures to be 2.85 and 2.28, respectively. There was no fecal coliform count in all the studied juice samples throughout the storage period, but total viable bacteria counts were 2.7x10⁴ cfu/ml, 1.84x10⁵ cfu/ml and 6.6x10⁴ cfu/ml for fresh juice and juice stored for 4 weeks at ambient temperature and refrigeration conditions, respectively. Overall, storage conditions had insignificant impact on the antioxidant properties and free radical scavenging capacity of the fruit juice; the slight changes observed were linked to usual molecular reactions. In conclusion, storage under refrigeration conditions elongated the shelf life of the juice.