Formulation of nutraceutical biscuits based on dried spent coffee grounds

Abstract

Background and Objective: Spent coffee grounds (SCGs) are the most abundant residual material (45%) obtained during the instant coffee production. Therefore, around 6 million tons of SCGs generated per year. The purposes of the present study consisted in evaluating the use of SCGs as innovative functional food ingredient in bakery products and study the effect of SCGs and their chemical constituents on the sensory properties, volatile constituents and rheological properties of the final product. Materials and Methods: Effect of mixing wheat flour with 2, 4 and 6% SCGs on rheological properties of the obtained dough was evaluated, then chemical, texture profile and sensory properties of the final product were studied. Results: Rheological properties of mixed wheat flour with SCGs dough was affected slightly with the higher dietary fiber content. Moisture content of SCGs reached to 58.98%, therefore, was dried to reach 7.47% to control the microbial activity. Protein, ash, crude fiber and total carbohydrate of SCGs were 8.97, 2.77, 51.86 and 78.5%, respectively. Also, SCGs is good source of lipids (13.89%). Chemical composition of biscuit indicated that increasing mixing level of SCGs (2-6%) has shown good enhancement in fiber and ashes compared to control sample. Volatile sensory active compounds of biscuits and its supplemented mix with SCGs was evaluated. Thirty-eight volatile compounds was separated and identified in the biscuit samples by using SPME/GC-MS analysis. Hunter color parameter of produced biscuit indicated that whiteness (L*) of control sample reached to 71.17, while mixing SCGs with wheat flour at levels 2, 4 and 6% decreased L* to 66.31, 54.88 and 43.88, respectively. Also, redness degree (a*) was lower in wheat flour (0.45) than SCGs (3.57). Therefore, a* value of biscuit increased with increasing mixing level of SCGs. Sensory properties of biscuits showed that increasing SCGs level decreased significantly the color score but overall acceptability not affected significantly. Conclusion: Spent coffee grounds contains sufficient amounts from dietary insoluble fibers, protein, lipids, ashes and lower glycaemic sugars. Mixing wheat flour with SCGs affected slightly the rheological properties of dough and overall acceptability of the final product. Therefore, the obtained biscuit could be recommended to patients with obesity-related diseases and diabetes in addition to people looking for foods intake with reduced energy.