Use of sodium metabisulphite and citric acid to control the degradation of nutraceutical compounds in dried tomato powder during prolonged storage

Abstract

Application of weak acid and preservatives on tomatoes has the potential to reduce the loss of functional properties during drying. The effects of using sodium metabisulphite (SMB) and citric acid (CA) to control the degradation of nutraceuticals in dried tomatoes were studied. The following treatments: T0 (control, no additives), T1 (1% w/v CA), T2 (0.5% w/v CA +0.5% w/v SMB), and drying methods (dehydration, sun, and solar) were used. The T2 pretreated samples, dried using the sun, solar, and dehydration had total soluble solids (TSS) (5.10%), total sugar (TS) (7.32 g/100 g), and rehydration ratio (RR) (2.0) and β-carotene (30.0 mg/100 g), lycopene (51.3 mg/100 g), ascorbic acid (14.1 mg/100 g), respectively. The T2 pretreated and dehydrated samples had a high Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl- 1- picrylhydrazyl radical scavenging activity. By using T2 treatment and dehydration, the tomato had the best functional properties, which would be used as optimal conditions for preserving tomatoes. Novelty impact statement: Hybrid Amukela Plus tomatoes pretreated with 0.5% w/v CA +0.5% w/v SMB and dried -in a food dehydrator preserved -further degradation of nutraceutical compounds and resulted in a β-carotene (30.0 mg/100 g), lycopene (51.3 mg/100 g), and ascorbic acid (14.1 mg/100 g) content during storage. These treatments produced dried tomatoes with over 50% Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl- 1- picrylhydrazyl (DPPH) radical scavenging activity. Solar and sun-drying treatments have significant damage on the nutraceutical compounds in the dried hybrid tomatoes.