Influence of Hydrogen Introduced Drying Atmosphere on Drying Kinetics, Phenolic Profile, and Rehydration Behavior of Tomato Slices

Abstract

The current study performed drying of tomato slices in a drying atmosphere with hydrogen gas (RAD_MIX; a gaseous mixture of 4% hydrogen, 5% carbon dioxide and 91% nitrogen), and compared with 100% air, 100% nitrogen drying environments. All the drying experiments were carried out at 60°C. Control samples and pretreated samples with 1% Potassium metabisulfite (KMS) treated samples were dried to a final moisture content of around 13.29% to 13.70% (wet basis), respectively. The drying behavior and quality characteristics including color change (ΔE), lycopene retention, total phenolics and rehydration ratio of the dried products were studied. The better retention of color and quality was observed in the sulfite pretreated and RAD_MIX dried sample. The color change (ΔE) was found to be 10.1, lycopene retention by 94.28% (3.3 mg/100 g), and the maximum rehydration ratio of 4.67 were observed in samples subjected to reduced atmospheric drying. Additionally, the color change was lesser for samples pretreated with KMS than the control samples. It was found that the use of hydrogen gas at 4% concentration (RAD_MIX) in the drying environment significantly impacted quality parameters of tomato slices. The sulfite pretreatment was advantageous technique in terms of moisture diffusivity, antioxidant compounds retention and rehydration ratio of tomato slices.