Qualitative Indices of Istamaran Date Variety Affected by Various Drying Methods

Drying of fruits and vegetables is one of the oldest methods for preserving foods. Drying not only affects the moisture content of the product, but also changes other physical, chemical and biological properties of the product including enzymatic activity, microbial spoilage, viscosity, hardness, taste and aroma. In order to study the occurring changes in dried product, qualitative characteristics including shrinkage, color and water rehydration are commonly evaluated. The purpose of this research was to study the effect of drying methods on qualitative indices for dried Istamaran dates. The drying methods were hot air, microwave and vacuum drying. The photos of the final product were taken using a digital camera. Then, color parameters (L*, a* and b*) of the samples were measured using Photoshop software. The amount of shrinkage for dried product was determined by liquid displacement method. For evaluating rehydration ability, water absorption capacity (WAC), dry matter holding capacity (DHC), and rehydration ability (RA) were also estimated. Results showed that the effect of drying method on WAC, DHC, and RA was significant (p