PROCESSING DATES OF LOW MARKET VALUE INTO FLOUR: EVALUATION OF QUALITY AND STORAGE STABILITY

Flour production is a way of valorizing dates, especially those of low market value. This flour can be used as an ingredient in biscuits, cakes, infant foods, etc. This work aims to assess the suitability of Moroccan dates for processing into flour and determine the nutritional, organoleptic and commercial qualities of the date flours. Six varieties of dates were studied: ‘Ademou’, ‘Bouijjou’, ‘Bouskri’, ‘Bouslikhene’, ‘Jihel’ and ‘Oum-N’hal’. The flour quality was evaluated by studying, among other criteria, water absorption index (WAI), water activity (aw) and sorption curves, and by carrying out sensory analysis. The storage stability was evaluated by keeping the flour at 25 and 45°C for 3 and 6 months. This work has highlighted the high suitability of ‘Bouskri’ and ‘Bouijjou’ for processing into flour. ‘Bouslikhene’ was not selected because of the sticky and doughy texture of its dried pulp. Beside high processing yields reaching 75.3%, the date flours showed interesting characteristics in terms of nutritional and organoleptic qualities. The WAI provided information on distinct rheological characteristics of the different flours and a_w data, lower than 0.41, lead to good microbial and enzymatic stability. The sorption curves of date flours also showed different hygroscopic behaviors. For storage stability, time and temperature had a significant effect on the physico-chemical properties of the flour. The negative effect was mainly represented by the color browning and the loss of the floury texture especially at the temperature of 45°C. The sensory evaluation of date flour was very encouraging and showed that this flour is a promising product to enrich and/or flavor food preparations.