Straightforward extraction of date palm syrup from Phoenix dactylifera L. byproducts: application as sucrose substitute in sponge cake formulation

Substitution of sucrose in foods is currently taking an increased interest either for economic-reasons or for improving the techno-functional qualities of foods by a sustainable-way. In this work, the production of date-syrup at a pilot-scale from Phoenix dactylifera L. by-products was successfully realized through a three-stage process, consisting of discontinuous solid/liquid extraction, clarification, and evaporation. Mass balance showed that date-syrup was obtained with a yield of 0.7 kg/kg and 70% brix. An economic evaluation based on Tunisian-market conditions permitted to estimate the cost (0.45 USD/kg) and the revenue (0.64 USD/kg). The feasibility of using date-syrup as sugar-replacer in a basic sweet-food ‘’sponge-cake” was thereafter assessed. The reformulated aliment possessed a texture profile close to the control with the adhesiveness and chewiness as the most affected parameters. However, a significant change in color was recorded caused by the pigment presence in date-syrup. Sucrose-substituted cakes presented a higher value of both total phenolic compounds (138.97 mgGAeq/100 g) and antioxidant activity. They were scored 4 to 5 level on a sensory-hedonic scale with the 100% enriched sponge-cake as the preferred one in term of taste. This innovative approach that integrates the concept of circular bio-economy, showed the proof of concept of using date-syrup as functional sweetener.