Studies on osmotic dehydration of green pepper (Piper nigrum L.)

Abstract

Experiments were conducted using a newly developed osmotic dehydration plant for the production of osmotically dehydrated green pepper. Several trials were done for different concentrations of NaCl (20% to 40%), time periods (1hr to 4hr)at different temperatures (30,40 and 50 0 C) and sample to solution ratios(1:2 to 1:6). Blanched and unblanched samples of panniyur and karimunda varieties were used for the study. The effect of process temperature, time, sample to solution ratio and concentration of the osmotic agent were studied. Optimum condition was selected on the basis of the water loss, solid gain and weight reduction. The results obtained for water loss in panniyur and karimunda were statistically analysed. It was inferred that the water loss was significantly influenced by concentration of the solute, osmosis time and sample to solution ratio. The best result obtained from panniyur blanched samples treated was 30% NaCl, 3 hr and 1:4 sample to solution ratio at 40 0 C and are selected for the secondary stage of drying using tray drier and freeze drier. The colour of dried product was recorded using Hunter lab colour flex meter and values were represented as colour difference from that of the fresh samples. The best colour was achieved at 50 0 C. The optimum conditions for secondary drying were assessed on the basis of volatile oil content, component and colour as 50 0 C and 6 hr for hot air drying and 50 0 C and 10 hr for freeze drier.