Osmotic Dehydration of Bamboo Shoots Enhanced by Centrifugal Force and Pulsed Vacuum Using Salt as Osmotic Agent

Abstract

Osmotic dehydration of bamboo shoots was carried out using salt as osmotic agent. Experiments were designed according to central composite rotatable design and response surface methodology was used to determine the optimum processing conditions. The effect of temperature, time and salt concentration on water loss (WL), solid gain (SG), hardness and color change was studied. The optimum values for temperature, time and salt concentration were found as 37C, 129 min and 12.10%, respectively. Further, optimized conditions were used to check the effect of centrifugal force and pulsed vacuum on osmotic dehydration. With increase in centrifugal force WL and rehydration ratio were found to increase whereas SG, hardness and L value were decreased. But with increase in vacuum, WL and SG increased, whereas, hardness and L value decreased. The optimized values of centrifugal force and vacuum pressure were found to be 2,800 rpm and 400 mm Hg, respectively. Practical Applications Osmotic drying of bamboo shoots helps preserve its nutrition and quality for a long time. Osmotic dehydration is mainly affected by process variables, such as process time, solution temperature and the concentration of the osmotic agent. But use of centrifugal force, vacuum and some other techniques shows the enhancement of osmotic drying process resulting in a product of better quality. The present study will provide suitable osmotic drying conditions using salt as an osmotic agent and their effect on quality. Also it will help to understand the effect of centrifugal force and pulsed vacuum on osmotic drying and quality of bamboo shoots viz. texture, color and cell disruption pattern.