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Bioactive components, ABTS radical scavenging capacity and physical stability of orange, yellow and purple sweet potato ( I pomoea batatas ) powder processed by convection‐ or vacuum‐drying methods
Author(s) -
Kuan LaiYee,
Thoo YinYin,
Siow LeeFong
Publication year - 2016
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13023
Subject(s) - ipomoea , food science , ingredient , chemistry , abts , orange (colour) , antioxidant , spray drying , vacuum drying , botany , freeze drying , dpph , chromatography , organic chemistry , biology
Summary This study aims to investigate the antioxidant properties and physical stability of convection‐ or vacuum‐dried orange, yellow and purple sweet potato ( Ipomoea batatas ) powder upon room temperature storage at different relative humidity ( RH ) of 33%, 43%, 54% and 75% for 25 days. Both convection and vacuum‐dried samples had lower total phenolic content ( TPC ), anthocyanin content and antioxidant activity compared to the fresh samples. Vacuum‐dried powder retained higher antioxidant activity than convection‐dried powder. Storage of the powder at high RH of 75% resulted in apparent clump formation, which was likely attributed to the decrease of glass transition temperature ( T g ). In general, purple sweet potato powder contained the highest TPC (255.0 mg GAE 100 g DW −1 ) and antioxidant activity (1924.0 μmol TEAC 100 g DW −1 ), while orange powder had the highest beta‐carotene content (127.2 mg 100 g DW −1 ). Vacuum‐dried sweet potato powder, which has relatively higher antioxidant activity, could be a potential functional ingredient or natural colourant for the food industry.