SOLVENT EXTRACTION OF ANTIOXIDANTS, PHENOLS AND FLAVONOIDS FROM SAUDI ARABIA DATES
Al udhaib, Rasha
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Cultivated dates are a stable food source in many countries, playing significant roles the people’s nutrition and their economy. The date palm fruit is the most important crop in the Kingdom of Saudi Arabia and is cultivated in nearly all regions of the Kingdom. Saudi Arabia is the world’s second-largest producer of dates, growing 16% of global date production. Saudi Arabia has more than 23.7 million date palm trees cultivated on more than 156,000 hectares and producing about 992,000 tonnes of dates annually. However, there has been a significant interest in recent years regarding the properties of antioxidants, phenols and flavonoids found in dates. These compounds have been found to neutralize free radicals inside the body which originate from metabolic. Free radicals are dangerous because they trigger chemical chain reactions within the body that damage or kill cells and as such they have been linked to a number of diseases. The aim of this study was to optimize extraction conditions of antioxidants, phenols and flavonoids from dates. First, the effects of sample: solvent ratio (1:20, 1:40 and 1:60), reaction temperature (25, 35, 45, 55 and 65°C), reaction time (1, 2, 3 and 4 h), solvent concentration (0, 50 and 75%) and solvent type (acetone and ethanol) on the yield of these compounds from ajwa date were investigated. The optimum extraction condition was used to compare the yields of these compounds from freeze dried ajwa date and fresh ajwa date as well as from 5 dates (Ajwa. Khalas, sukkari, red sukkari and sofry). The three hours reaction time at 55°C with a sample: solvent ratio of 1:20 and 75% ethanol were the optimum extraction conditions for antioxidants yield while 3 h reaction time at 65°C with a sample: solvent ratio of 1:20 and 75% acetone were the optimum conditions for phenols and flavonoids extraction from fresh ajwa date. Freeze drying procedure obtained higher yields for antioxidants (84.60%), phenols (55.70%) and flavonoids (29.99%) than those obtained from fresh ajwa date. Ajwa dates had the highest antioxidants, phenols and flavonoids (73.10 mg/g, 355.24mg/g and 57.52mg/g), followed by khalas (62.85 mg/g, 252.01 mg/g and 52.47 mg/g), sukkari (62.45 mg/g, 204.65 mg/g and 43 mg/g), red sukkari (61.10 mg/g, 200.59 mg/g and 41.65 g/mg) and sofry (60.39 mg/g, 184.05 mg/g and 41.22 mg/g).