Studies on Quality Attributes of Onion (Allium Cepa) During Storage

Abstract

The present investigation was carried out to study the effect of production treatments, storage period and ambient storage conditions on physic-chemical (moisture content, TSS, Optical density, pH, acidity, ascorbic acid, rotting, sprouting, black mold), bio-chemical (protein and carbohydrate), PLW (0/o) and microbial (TPC) quality of stored onion. The onion bulbs with different production treatments were graded according to their size i.e. large, medium and small. The graded onion bulbs were then kept in wooden baskets for storage. Several parameters were taken into consideration for analyzing the quality of stored onion. The samples were stored under ambient storage conditions (temperature and RH) and several quality were evaluated for fresh as well as stored samples after 30, 60, 90, 120, 150,180 & 21 0 days of storage. The study revealed that the moisture content, TSS, acidity, PLW, ascorbic acid, rotting, sprouting, black mold and optical density of stored onion bulbs increased with increase in the storage period. The pH and amino acid decreased with increase in the storage period whereas protein and carbohydrate concentration initially increased and then decreased due to increase in humidity. The highest microbial growth value (TPC) of 8684x1 02 cfu/ml was observed in case of T6 (Neem Cake + Vermi Compost) after 180 days of storage. The lowest microbial growth value of 7.182 x1 02 cfu/ml was observed in case of T 1 (Neem Cake) after 180 days of storage. The microbial growth increased with increase in storage temperature. The microbial growth was not observed upto 30 days of storage and the bulbs were acceptable till 120 days of storage. The rotting, sprouting and black molds were not observed till 60 days of storage. It was determined that these parameters increased with increase in storage temperature and RH. Among 18 treatments, T18 Control (Full doze of fertilizers) showed lowest sprouting and black mold. Thus, it was considered better treatment for storage of onion bulbs as compared to other production treatments.