Abstract:
To evaluate the processing adaptability of Sedum aizoon L. and expand its utilization, five pretreatment techniques (untreated [UT], boiling water blanching [BWB], color protection+water blanching [CPB], steam blanching [SB], and freeze thawing [FT]), followed by two drying methods (hot-air drying [HA], and heat-pump drying [HP]) were used. Ten types of water spinach powders, namely UT HP, UT HA, BWB HP, BWB HA, CPB HP, CPB HA, SB HP, SB HA, FT HP, and FT HA, were obtained. Changes in color, bioactive compound levels, and antioxidant capacities were compared. UT HP had the highest content of gallic acid and kaenaphthol, but had low color brightness, low chlorophyll content, and a longer drying time. CPB HP had a shorter drying time, the highest Vc content, and relatively high antioxidant levels, but lower gallic acid content. The contents of total phenols, total flavonoids, and quercetin were the highest in SB HP, whereas other quality indices fell within intermediate ranges. FT HP had the best color, the highest content of chlorophyll, and the highest free amino acid content, but lower contents of total phenols, total flavonoids, quercetin, and kaempaphthol, and a lower antioxidant capacity. Principal component analysis revealed similarities in water spinach quality among BWB HP, CPB HP, SB HP, BWB HA, CPB HA and SB HA, but there were distinct differences between UT HP, FT HP, UT HA, and UT HA. This study comprehensively compared the advantages and disadvantages of different pretreatments and drying techniques for S. aizoon. The findings of this study can serve as a valuable reference for guiding the selection of drying techniques in the development of functional foods.
