Impact of Hot Water Pre-Treatments on the Drying Efficiency and Quality of Dates cv. Medjool

Abstract

Dates are considered high energy nutritional fruits as they are packed with plenty of minerals, vitamins and sugars. Among various options available for processing and value addition, dry dates are one of the best possible alternatives to convert doka/khalal stage fruit into a high value product. However, the technology for their production is limited to a few traditional date growing countries and research is limited in the countries with expanding areas. Thus, the protocol for development of dry dates was standardised and the effect of different blanching intervals (5, 10 and 15 min) on the drying and quality parameters were studied. The rate of drying, dehydration ratio and rehydration ratio were found to increase with increasing hot water dipping durations while a 10 min hot water dip was found to be best for retaining the best sensory parameters of taste, colour/appearance and flavour. The total colour difference (∆E) was also maximal (71.10) in the date fruits exposed to a 10 min dip treatment. The reducing sugars decreased and non-reducing sugars increased with increasing hot water dipping periods while there was no significant variation in the total sugar content of the treated dates. The tannins responsible for acrid taste were also reduced to a minimum (1.43%) compared to control (2.52%) fruits. Thus, the fruits of date cv. Medjool being bulky and fibrous with more dry matter content are well suited for dry date preparation.