Impact of drying methods on physicochemical and sensory properties of apricot pestil

Abstract

Fruit leathers, or traditionally named as pestil are intermediate moisture pectic gels, eaten as snack, manufactured by dehydration of fruit pulp into leathery sheets. The aim of the study was to evaluate physicochemical and sensory properties of apricot pestil dried with different methods. One group was sun dried, other group was dried in vacuum oven at 55 C and the last one was dried in microwave oven (90 W). Analysis of moisture, water soluble dry matter, pH, titratable acidity, total and reducing sugar, hydroxymethylfurfural, total phenolic compounds, antioxidant activity, minerals (K, Ca, Mg, Zn), color (L*, a*, b*) and sensory analysis were carried out. The moisture contents of apricot pestil samples were between 13.12 +/- 1.35 - 14.39 +/- 0.41 gm/100 gm. The HMF content of samples was affected by drying method. The HMF contents of microwave oven dried, vacuum oven dried and sundried pestil samples were 13.62 +/- 0.78, 19.39 +/- 0.26 and 45.64 +/- 1.29 mg/kg, respectively. Total phenolic compounds in samples were determined as between 110.03 +/- 0.72 - 121.24 +/- 6.19 mg GAE/100 gm. Retention of antioxidant activity of the sundried, microwave oven dried and vacuum oven dried samples was 59.80%, 39.23% and 19.15%, respectively. The mineral contents of pestil samples were higher because of increasing dry matter content. When comparing drying times, the shortest was observed in microwave oven drying followed by sun drying and vacuum oven drying. Drying methods considerably influenced the color changes of pestil samples. Chromatic parameters a*, b*, Delta E-ab* and C*(ab) were found higher in microwave oven dried samples. Sensory evaluation analysis showed that all of the samples were acceptable by the panelists. The results of the analysis were important for selecting the quality criterion and for characterizing of this traditional product.