Effects of different drying–solidification processes on physical properties, volatile fraction, and antioxidant activity of non-centrifugal cane brown sugar

Abstract

Three drying–solidification processes, namely open pan (OP), horizontal thin-film (HTF), and vertical thin-film (VTF) methods, produced non-centrifugal cane brown sugars with different quality profiles, represented by physical properties, volatile fractions, and antioxidant activities. The OP brown sugar had lighter color due to the lower temperature used in its drying–solidification process, and a larger open-surface design to facilitate evaporation in its processing line made the brown sugar contains much smaller amount of volatile aroma components. On the other hand, higher evaporation temperature in the drying–solidification processes for HTF and VTF enhanced the accumulation of volatile fractions. The brown sugars predominantly comprised sweet-caramel aroma, and to a less extent, nutty-roasted, acidic, and grassy characteristics owing to the presence of acidic aroma components such as butanoic and 3-methyl butanoic acids, along with 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 5-methyl-2-pyrazinylmethanol, and 2,5-dimethyl-pyrazine. The production lines discriminated their aroma profiles due to the odor detectability of these aroma compounds wherein ketones and pyrazines were highly detected in OP brown sugar, acids and sulfurs in HTF brown sugar, and alcohols in VTF brown sugar. Additionally, the higher temperatures used in thin-film evaporation processes enhanced total phenolic content of brown sugar, and consequently its antioxidant activity.