Evaluation of Physicochemical, Rheological, Microbial and Sensory Properties of Canned Date

Numerous methods have been used to prolong the shelf life of date fruit including fumigation, packaging, irradiation, ozonation, cold storage, freezing, etc. Each of these methods has some advantages and disadvantages. However, the amount of loss dates in Iran is approximately 20% annually. The aim of this study was to apply a new method (hurdle technology) to prolong the shelf life while keeping the natural mode of the date fruit.

There were 27 different treatments of canned date in this study by the combination of three hurdles: pH (4.5, 4.0 and 3.5), temperature (boiling in date syrup for 30, 25 and 20 minutes) and aw (by increasing the total soluble solids to 70, 65 and 60%). Zahidi variety and date syrup were used to produce the treatments. The pH value and total soluble solids, as well as microbial and sensory properties (colour, taste, texture, appearance and overall acceptability) were evaluated in six months. The hardness of date flesh was evaluated after six months of production. T-test was used to analyze the pH, brix and hardness, and ANOVA test was used to evaluate the effect of time on sensory properties.

The pH value and total soluble solids significantly (p<0.05) increased in the date syrup during six months. No growth was seen on the microbial media. The effect of time on the sensory properties of canned date was not significant (p>0.05), and the treatment number 5 had the best overall acceptability point.

The canned date - produced using hurdle technology- had satisfactory microbial and sensory properties. So, this process can be applied for replacing the traditional and contemporary methods for preserving date fruit.