Compositional and functional characteristics of dates, syrups, and their by-products

Three native sun-dried date varieties from Oman (namely Mabseeli, Um-sellah, and Shahal), as well as their syrups and by-products (press cake and seed) were examined for their proximate composition, dietary fibre, total phenolics, and total antioxidant activity. Carbohydrate was the predominant component in all date varieties, syrups, and their by-products, followed by moisture, along with small amounts of protein, fat, and ash. Press cakes had the highest protein content, ranging in concentration from 3.62 g/100 g in Shahal to 5.23 g/100 g in Mabseeli, whereas fat was the highest in seeds and ranged from 5.02 g/100 g in Mabseeli to 5.90 g/100 g in Um-sellah. Seeds and press cakes were found to be good sources of dietary fibre, varied between 77.75 and 80.15 g/100 g fresh weight and between 25.39 and 33.81 g/100 g fresh weight, respectively. Among dates, syrups, and their by-products, seeds had the highest contents of total phenolics (3102–4430 mg of gallic acid equivalents/100 g fresh weight) and antioxidant activity (580–929 μmol of Trolox equivalents/g fresh weight). The results obtained suggest that date by-products (particularly seeds) serve as a good source of natural antioxidants and could potentially be considered as a functional food or functional food ingredient.