Influence of pretreatment with ethanol and drying temperature on physicochemical and antioxidant properties of white and red pulp pitayas dried in foam mat

Abstract

Pitaya is a perishable fruit with a high content of bioactive compounds. This study aimed to evaluate the influence of ethanol pretreatment (95% dripped on the surface of the foam at a rate of 0.05 mL.cm⁻²) and temperature (50 and 70 °C) on moisture content, water activity, solubility, color, ascorbic acid, antioxidant capacity (DPPH and FRAP) e betanin and betaxanthin retention of white and red pitaya powdered pulps and to determine an optimal process condition. Pretreatment and higher temperature resulted in increased solubility and antioxidant capacity of powdered pulps. The total color difference was influenced by pretreatment and drying temperature, but in different ways according to the variety. In the pretreated red pulp powders, 70 °C resulted in higher retention of ascorbic acid and 50 °C resulted in increased retention of betanins and betaxanthins. The optimal treatment for white and red pulps was the use of pretreatment and a temperature of 70 °C.

Keywords:

• Dragon fruit
• foam mat drying
• ascorbic acid
• antioxidant capacity
• betalains

Additional information

Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo a Pesquisa de Minas Gerais (FAPEMIG).