Effect of air drying temperature on rehydration ability, colour development and ascorbic acid content of red pepper

Abstract

The effect of air-drying temperature on the rehydration ability, colour and ascorbic acid content of red pepper was investigated. The rehydration ratio, non-enzymatic browning and colour loss increased with increase in air-drying temperature, while the water holding capacity decreased with increase in air-drying temperature. The vitamin C content of red peppers decreased linearly from 133.1 to 48.79 mg/100 g as the air-drying temperature increased from 30^oC (ambient temperature) to 70^o C, with a maximum loss of 63.34 % vitamin C observed in red pepper dried at 70^oC. The chromatic parameters L*, a* and b* decreased from 32.21 to 20.59, 16.11 to 7.18 and 5.12 to 2.33, respectively as the air-drying temperature increased. These values indicate that air drying temperature led to red pepper modifications that caused quality degradation. The regression models that could be used to adequately express the relationships existing between the quality parameters of red pepper and air-drying temperature were established.

Keywords: Red pepper, rehydration, chromatic colour, ascorbic acid, drying temperature