Physio-chemical and quality characteristics for date juice at khalal stage

Abstract

Background and Objective: The importance of the date in human nutrition comes from its rich composition of carbohydrates, minerals, dietary fibre, vitamins, fatty acids, amino acids and protein. At khalal stage, the percentages of protein, fat and ash decrease to 2.7, 0.3 and 2.8%, respectively. Most dates are consumed at the rutab (semi-ripe) and tamr (fully-ripe) stages. Consumption of processed dates, however, is rapidly and steadily growing. The present investigation was to make a comparison between date juices extracted from Egyptian varieties (Zaghloul, Samani and Hayany), effected with ascorbic acid added and evaluates the chemical composition, physical characteristics, mineral analysis, color and quality attributes. Materials and Methods: Chemical analysis such as protein, ash, total sugars and total phenols, physical characteristics i.e., T.S.S, pH, total acidity and total solids, organoleptic evaluation as appearance, color, taste, flavor and overall acceptability and total microbiological counts were measured. Statistical analysis was done by using a one-way analysis of variance (ANOVA) and using Assistant computer programs and Least Significant Difference (LSD), statistical significance was set at p ≤ 0.05. Results: Total Soluble Solids (T.S.S) % and Brix/acidity ratio were high in samani date juice. Zaghloul date juice had the highest contents of total soluble solids %, total sugars % and total phenols % while, Hayany date juice contained higher contents of total acidity % (as citric acid), protein and ash. Hayany date juice contained a high level of sodium, potassium, calcium, phosphorous and magnesium. Addition of ascorbic acid at level 1% improved all values of organoleptic properties determined for all different date juices compared with controls. Treatment of selected different varieties of date juices samples with pasteurization and potassium sorbate reduced total bacterial, yeast and mould counts to acceptable levels through the storage periods. Conclusion: Different varieties of date juices were produced from Zaghloul, Hayany and Samani at khalal stage rich in minerals and total sugars. Addition of ascorbic acids to date juices at level 1% slightly increased the total acidity % and all color parameters compared to controls. It improved the organoleptic properties for all different date juices. Pasteurization and potassium sorbate reduced total bacterial, yeast and mould counts and increased the storage periods for more than 6 months.