EFFECT OF CHEMICAL PRETREATMENTS ON THE PHYSICAL CHARACTERISTICS OF DEHYDRATED ONION SLICES

The present investigation entitled “Effect of chemical pretreatments on physical characteristics of dehydrated onion slices” was carried out in Department of Post Harvest Technology at College of Horticulture, Dr. Y.S.R. Horticultural University, Venkataramannagudem, West Godavari District of Andhra Pradesh during 2017-18 with an objective to study the effect of different pretreatments on physical characteristics of onion slices. In preparation of dehydrated onion slices, four pre-treatments viz., 0.5% KMS, 2% CaCl2, 2% NaCl and control and two varieties viz., Agrifound Dark Red and Phule Safed were used. The experiment was conducted in Completely Randomized Factorial Design with the above two factors at unequal levels and replicated thrice. Among the pretreatments and varieties, onion slices of Agrifound Dark Red pretreated with 0.5% KMS was superior in terms of recovery percentage (14.85%) and the untreated Phule Safed variety (9.05%) with lower recovery. Regarding moisture content, lowest (3.98%) was recorded in onion slices pretreated with 2% CaCl2 and highest (4.69%) was recorded in untreated onion slices, among varieties lowest moisture content was observed in Agrifound Dark Red (4.24%) and highest in Phule Safed (4.29%). Among the pretreatments, lowest dehydration ratio was observed in the onion slices pretreated with 0.5% KMS (7.18) and highest in untreated onion slices (9.61) where as in varieties, lowest dehydration ratio was observed in Agrifound Dark Red (7.41) and highest was found in Phule Safed (8.85). Concerning rehydration ratio, maximum in 0.5% KMS (5.10) and minimum in untreated onion slices (4.80), maximum in Phule Safed (4.97) whereas minimum in Agrifound Dark Red (4.95). Among the pretreatments and varieties, water activity was recorded minimum in 0.5% KMS (0.52) and maximum in untreated onion slices (0.56) and minimum in Agrifound Dark Red (0.54) whereas maximum in Phule Safed (0.55). It was found that, onion slices pretreated with 0.5% KMS were best and recorded low microbial count.