Abstract:
Amla, a richest source of vitamin C were subjected to different pretreatments and drying
temperature to investigate the effect of pretreatments and drying temperature on quality
characteristics of dehydrated amla. Amla were subjected to following pretreatments viz. cut
blanching, cut sulphiting, cut (blanching + sulphiting), whole blanching, whole sulphiting,
whole (blanching + sulphiting) and dried at 60±2ºC at cabinet drier to a final moisture
content 6±1%. Further, the best pretreatment was then subjected to 3 different drying
temperature range viz, 55±2ºC, 60±2ºC and 65±2ºC to a final moisture content 6±1%.
Among the different pretreatments, samples pretreated by pretreatment whole (blanching
+ sulphiting) showed higher retention of vitamin C (411.3 mg/100 g, db) (71.18%) along
with improved rehydration ratio (2.227:1), coefficient of rehydration (0.422) and best
organoleptic properties. Amla pretreated by pretreatment whole (blanching + sulphiting) and
dried at 55±2ºC showed maximum retention of Vitamin C, best rehydration characteristics
and better organoleptic property compared to other temperature range. Vitamin C retention
was maximum at temperature 55±2ºC (429.67 mg/100 g, db) (74.36%) which was
significantly different (p≤0.05) with the samples dried at other temperature range.
Temperature showed significant effect on rehydration ratio. Amla dried at 55±2ºC showed
maximum rehydration ratio (2.507:1) and coefficient of rehydration (0.4747). Sensory
quality of the product dried at 55±2ºC was found superior to that obtained from 60±2ºC and
65±2ºC. The sensory attributes of all three products; dried at 55±2ºC, 60±2ºC and 65±2ºC
were found significantly different (p≤0.05) to each other. The final optimized dried amla
composition was found 6%, 3.3, 5.2%, 4.6%, 2.4% and 429.67 mg/100 g in terms of moisture
content, pH, total sugar, reducing sugar, acidity and vitamin C respectively.
Description:
A dissertation submitted to the Department of Food Technology, Central Campus of
Technology, Tribhuvan University, in partial fulfillment for the degree of B.Tech. in
Food Technology