Drying effects on the antioxidant properties of tomatoes and ginger

• Published in: Food chemistry Vol. 173; pp. 156 - 162
• Main Authors: Gümüşay, Özlem Aktürk, Borazan, Alev Akpınar, Ercal, Nuran, Demirkol, Omca
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15-04-2015
• Subjects: Antioxidant properties; Antioxidants - chemistry; Ascorbic Acid - chemistry; Desiccation - instrumentation; Desiccation - methods; Drying; Food Preservation - instrumentation; Food Preservation - methods; Ginger; Phenols - chemistry; Plant Extracts - chemistry; Solanum lycopersicum - chemistry; Thiols; Tomatoes; Zingiber officinale - chemistry; Antioxidant properties; Thiols; Tomatoes; Ginger; Drying
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.09.162

•We determine loss of antioxidant properties of tomatoes and ginger after drying.•We used sun, oven, vacuum oven and freeze drying techniques.•We analysed total phenols, vitamin C, cupric ion reducing antioxidant capacity and thiols.•Thermal drying methods caused significant losses in the contents of all samples.•Freeze drying displayed better antioxidant properties than the other methods.
In this study, the effects of four different drying processes, sun drying (SD), oven drying (OD), vacuum oven drying (VOD) and freeze drying (FD) for tomatoes (Solanum lycopersicum) and ginger (Zingiber officinale) in terms of thiolic and phenolic contents have been studied. Thiol content, total phenolic content (TPC), ascorbic acid (AA) content, and cupric ion reducing antioxidant capacity (CUPRAC) were determined in fresh and dried samples. Glutathione (GSH) and cysteine (Cys) were determined as the thiol contents of tomatoes and ginger. Significant losses were observed in the contents of TPC, AA, GSH and Cys and CUPRAC values in all samples that were dried using the thermal method. There was a statistically significant difference in the losses of the TPC, AA, and thiol contents between the use of thermal drying and freeze drying (except Cys in tomatoes) methods. Freeze dried tomato and ginger samples have been found to have better antioxidant properties.