Partial removal of water from red pepper by immersion in an osmotic solution before drying

Abstract

Red pepper is dried for use as a spice. When using solar energy to dry it, there are no energy costs but using other energy sources such as fuel or electricity, the production cost of red pepper spice increase. Due to the fact that energy is becoming expensive globally, it can be envisaged that osmotic dehydration gains more popularity as a pre-processing dehydration step. In this study, red pepper samples were cut into square and immersed in the osmotic solutions prepared at three different concentrations, a defined ratio (sample/solution; g/ml) and several temperatures during osmotic dehydration process time. Water activity, color, solid content, water loss and solid gain of samples were determined during osmotic dehydration process taking place in solutions at different concentration, temperature and time. Statistically, all dependent variables have effect on osmotic dehydration. 60 min of the process was found as the critical point for water loss-solid gain relation. The effect of concentration was significant on water activity of sample. Water activities of samples whose initials were greater than 0.90 reduced below the level of 0.8 at the end of dehydration time, with the exception of a few samples; visible color values were influenced by the process.

Key words: Red pepper, sea salt, water activity color, osmotic dehydration.