Pretreatment Effect of potassium metabisulfite and drying methods on some quality indicators of dried fig and dried fig treated with hot water steam (Habbol)

Abstract

This study was carried out in Department of Food Science, Faculty of Agriculture, Damascus University in 2017 season, which included immerse fig with potassium metabisulfite solution at tow different concentration (0.1% and 0.5%) for 15 min, and drying fig to a moisture content not exceeded 24% by tow drying methods (natural drying in shade and heat drying by hot air at 60˚c), and also processing fig treated with hot water steam (Habbol), in order to study the effect of drying methods on some chemical indicators (total sugars, pH, ash, acidity and moisture), total phenols and antioxidant activity according to DPPH, the study also included the sensory characteristics of the samples studied.

Thermal Dried figs samples treated with potassium metabisulfite at concentration of 0.5% evaluated  high percentage of acidity (0.324% dry weight basis) and low pH to (5.21), while ash declined to (2.75% on a dry weight basis). In thermal dried figs samples treated with potassium metabisulfite at concentration of 0.1%. The content of total sugars ranged between 48.43 - 54.59% in dried figs samples. Habbol fig samples manufactured from dried figs in the shade and treated with potassium metabisulfite at concentration 0.1% showed a noticeable decrease in the moisture content (14.64%) and a marked increase in ash content (3.69% dry weight basis). The content of total sugars increase to (55.19% dry weight basis) in samples of habbol fig samples manufactured from thermal dried control fig. Sensory evaluation of habbol fig samples manufactured from thermal dried figs samples using hot air and treated with 0.5% potassium metabisulfite was the best comparing with all samples. Habbol fig sample manufacturer from dried fruits in shadow and treated with potassium  metabisulfite 0.5% showed a rise in total phenol content which (324.67 mg/100 g dry weight) and antioxidant activity which (79.63% in a dried sample and 66.48% in habbol) respectively.