Evaluating the Nutritional, Physicochemical, and Quality Characteristics of Different Treated Freeze-dried Barhi Dates

Hassan Barakat^*Muath AlmutairiTareq Al Sequel

• Department of Food Science and Human Nutrition, College of Agriculture and Food, Qassim University, Buraydah, Saudi Arabia

Barhi dates at the Khalal stage exhibit high perishability, which results in considerable post-harvest losses. Implementing freeze-drying, either independently or combined with pre-treatments, represents a promising strategy and enhances the product's quality. Therefore, the current study evaluated the impact of freeze-drying alone or combined with various pre-treatments on the nutritional, physicochemical, and quality char-acteristics of fresh Barhi dates. The pre-treatments included soaking in sodium metabisulfite (Met-D) 1 g L-1, ascorbic acid (Asc-D) 1 g L-1, and citric acid (Cit-D) 1 g L-1 for 2 min, blanching (Bla-D) for 5 min, and blanching followed by ascorbic acid soaking (BAs-D) 1 g L-1 for 2 min, compared to untreated freeze-dried samples (RD). The freeze-dried dates were then analyzed for proximate composition, mineral content, total phytochemicals and polyphenolics, antioxidant activity (DPPH, ABTS), sugar profile (HPLC-RID), instrumental color (Hunter Lab), water activity (aw), and in vitro glycemic index (GI) and glycemic load (GL). Freeze-drying consistently reduced moisture content to a stable range of 6.21–7.16% without a remarkable effect on proximate composition or mineral content. All treatments yielded stable products with low aw (0.22 – 0.26). Asc-D and Cit-D treatments significantly enhanced the retention of total phenolic compounds (TPC) and flavonoids, with BAs-D exhibiting the highest TPC and most potent antioxidant activity. HPLC analysis observed that Met-D and Cit-D treatments had the highest extractable polyphenols, whereas p-hydroxybenzoic acid was quantified as the predominant phenolic acid. The glycemic index (GI) and glycemic load (GL) re-mained low (39.72–39.80 and 35.32–35.63, respectively. Color analysis demonstrated that Met-D and Asc-D preserved lightness, while blanching induced browning. In conclusion, freeze-drying combined with ascorbic or citric acid pre-treatments effectively preserves bioactive compounds, antioxidant activity, and shelf stability while maintaining a low glycemic index, providing a viable approach to reduce post-harvest losses and enhance the commercial value of Barhi dates. These findings provide a robust framework for industrial applica-tions, supporting nutrient-dense date products and contributing to sustainable agricultural practices.