Physico-Chemical, Functional and Antioxidant Evaluation of Some Gluten-free Flours Formulas Compared with Available Commercial Formula

Gluten-free (GF) products are made using commercial flours formulas and are poor in protein, fiber, minerals and have weak physical properties that affect the quality of the final products. These factors are responsible for hampering adherence to the GF diet and for general dissatisfaction. The aim of this work was to evaluate the physio-chemical, functional and antioxidant evaluation of some combinations of GF flours formulas that have been prepared compared with available GF commercial flour formula in the local market. The moisture content of Gluten-free flour (GFF) formula sold in the local market used in the research was 12.60%. On the other hand, the prepared formulas' moisture content ranged from 12.23% (F2) to 12.90% (F3). The highest protein content was recorded with F2 and F4 formulas with no significant difference (p<0.05). Gluten-free flour formula had the lowest protein content (5.07% on a dry weight basis (DWB). In comparison to control (GFF), the amount of ash and crude fiber recorded in F2 doubled. The ash and crude fiber contents of the various formulas differed significantly. The GFF had the lowest ash and crude fiber content (0.51 and 0.31%, respectively on DWB). The highest values of total phenolic compound and antioxidant activity was observed in the F2 formula (313.15 mg/100g and 7.95%, respectively), followed by the F4 formula (226.56 mg/100g and 7.22%, respectively), then the F1 formula (223.57 mg/100g and 6.62%, respectively) on DWB. While, the lowest value was in the commercial flour formula sold in the local market (GFF) (75.10 mg/100g and 3.23%, respectively) on DWB. Gluten-free flours formulas exhibited high values for the water holding capacity in samples F2 (164.98%) and F1 (134.17%). While, GFF commercial flour formula showed lower water binding capacity in comparison to other GF flours formulas. Significant differences in the oil holding capacity of GF flours formulas were also observed. The mean values showed higher oil holding capacity for F2 (145.92%), followed by F4 (138.51%), F1 (130.11%) and F3 (126.64%), whereas, the lowest 75.43% was for GFF. The GF composite flour samples have close values and non-significant variations at p≤0.05 in the protein solubility. The increase in the values of emulsion stability and foam stability determined for GF flours formulas were significant at p≤0.05 as compared with those determined for the GFF commercial flour formula sample.