Roasting-Induced Changes in the Chemical Composition, Fatty Acid Profile, and Bioactive Properties of Kaluteh Date Pits

Date pits (DPs), accounting for approximately 10% of the total fruit weight, are a major by-product of the date processing industry and are generated in large quantities as waste. By containing valuable nutritional and bioactive compounds, DPs have considerable potential for utilization as functional ingredients in food applications. The present study aimed to investigate the chemical composition, fatty acid (FA) profile, and total phenolic content (TPC) of Kaluteh DPs, as well as to evaluate the effects of roasting and extraction conditions on their bioactive properties. Raw DPs contained approximately 74.92% carbohydrates, 9.30% fat, 8.45% moisture, and 6.21% protein. FA analysis revealed that lauric acid was the predominant saturated FA, whereas oleic acid was the major unsaturated FA. Response surface methodology indicated that increasing extraction temperature, extraction time, and solvent-to-solid ratio (SS_R) enhanced both TPC and antioxidant activity. The optimum conditions for maximizing TPC were 63°C, 2.03 h, and a SS_R = 0.017 g/mL, whereas the highest antioxidant activity was achieved at 51°C, 3 h, and a SS_R = 0.016 g/mL. Under these optimized conditions, roasted DP extracts had a TPC = 14.8 mg GAE/g and a DPPH radical scavenging of 98.53%. Roasting also reduced moisture content to 4.05% and induced changes in FA composition, with oleic and lauric acids remaining the predominant FAs in roasted samples. Overall, roasting and extraction optimization significantly improved the bioactive characteristics and nutritional value of Kaluteh DPs, highlighting their potential as a natural source of antioxidants and functional ingredients for food applications.