Biochemical response of sweet potato to bemul-wax coating combined with calcium chloride treatment during ambient storage

Sweet potato (Ipomoea batatas Linn) tuber is a very nutritious but highly perishable crop that is subject to high wastages due to non-availability of appropriate storage techniques. This work assessed the effectiveness of treating the tubers with calcium chloride dip (CCD), bemul-wax (B-wax) and their combinations (CCD/B-wax) at ambient storage conditions (24.9 ± 4.0°C and 44.6 ± 18.4% RH). Some biochemical parameters of each treated sample were assessed and compared with the control for 20 days storage period. There were significant reductions (P < 0.05) in weight loss by B-wax and CCD/B-wax. CCD and CCD/B-wax caused significant reductions in pH, total amino acid and pectin esterase. Also, all the treatments caused significant reductions in ascorbic acid, phenylalanine ammonia lyase, α-Amylase and alcohol dehydrogenase activities. There were significant reductions in polyphenol oxidase activity by B-wax. In conclusion, while all the treatments proved to be effective to varying degrees, CCD/B-wax seemed to be the most effective in preventing spoilage in the tuber.   Key words: Biochemistry, storage, bemul-wax, calcium chloride dip, combined agent, sweet potato.