Quality Evaluation of African Eggplant Stored in Evaporative Coolers

Abstract

Postharvest cooling of fresh produce is essential to delivering high quality produce to the consumer. African eggplants are chilling sensitive at temperatures below 10°C, there is need to store them at higher temperatures because of their tropical nature. Evaporative coolers suitable for tropical fruits storage were therefore designed and constructed. Essentially, the evaporative coolers comprised of double burnt-brick walls (1.29 × 2.55× 2.56) m external and (1.13 × 1.27 × 2.08) m internal (L × W × H). A study was conducted to evaluate the physicochemical, microbial and sensory parameters of African eggplant stored in two evaporative coolers- aluminum-cladded burnt-clay-brick evaporative cooler (ABBEC) and non-cladded burnt-clay-brick evaporative cooler (NBBEC). Weight loss, total soluble solids, total titratable acidity, beta carotene content, ascorbic acid content, pH and microbial load were assessed during storage. Metabolic rates of African eggplant were highest at ambient storage, intermediate in NBBEC with the least value in ABBEC. Beta carotene, ascorbic acid and acidity decreased while total soluble solids, pH and microbial load increased during storage of African eggplant. The evaporative coolers reduced the storage temperature and increased the relative humidity within normal level of storage thereby extending the shelf life of eggplant from ten days at ambient to twenty-one days in ABBEC storage condition.  ABBEC storage is therefore recommended for stop gap extension of shelf lives of fresh produce.