Agricultural products of high moisture contents require appropriate drying method for nutrient component retention, particularly the bio-fortified crops, such as orange-fleshed sweet potato (OFSP). Different drying (oven, open sun, freeze drier, direct solar and indirect solar dryings) methods and slice thickness of 2 mm and 4 mm were applied in processing fresh OFSP samples to flour. The study determined stability of β-carotene (µg/g) dry weight (DW) in OFSP by different drying methods and slice thickness. The result revealed high beta-carotene retention ranging from 104.48 µg /g – 504.08 µg /g in the flour samples. Beta-carotene found in 2mm thickness OFSP flour samples was significantly (p<0.05) higher than the level from 4 mm thickness flour samples. Indirect Solar drying method promoted β -carotene retention, having values of 504.08 µg/g (2mm thickness) and 432.85 µg/g (4 mm thickness) in flour samples, while lowest β -carotene content was found in OFSP flour samples dried with open drying method for the 2 mm thickness (115.72 µg/g) and 4 mm thickness (104.48 µg/g), respectively. Similarly, rehydration ratio was significantly (p<0.05) higher in 2 mm thickness of OFSP (2.76-3.91) flour samples than in 4 mm (2.22-2.87) OFSP flour samples. Rehydration ratio was highest in 2mm (3.91) and 4 mm (2.87) samples of freeze drying method. Slice thickness positively affected the beta carotene retention and rehydration ratio on OFSP flour more than drying methods. Therefore, 2 mm slice thickness and indirect solar drying methods are recommended for processing of high quality β -carotene OFSP flour.
Share this article