Technological and nutritional studies on Sweet Lupine seeds and its applicability in selected bakery products

II Abstract Legume seeds are an abundant source of proteins and, among them; lupine is one of the richest. Lupine seed deserves great interest due to its chemical composition and augmented availability in many countries in recent years. The aim of this research was to study the chemical and nutritional properties of sweet lupine seeds and effects of its addition at different concentration (5, 10 and 15 %) on the dough rheology and backing characteristics of wheat flour enrichment lupine flour and lupine fiber. Lupine flour showed higher levels of moisture, crude protein, ash, crude fat and dietary fiber than the wheat flour. Conversely, wheat flour showed higher levels of starch. The lupine fiber showed higher levels ash, crude fat and dietary fiber than the wheat flour. Essential amino acids (lysine, threonine, isoleucine, phenylalanine and tryptophane) in lupine flour were higher than those in wheat flour except methionine content which was higher in wheat flour (1.7 g/kg). The lupine flour showed higher levels of total phenolic and total flavonoids than the wheat flour. Conversely, wheat flour showed higher levels of total flavonols. Results clearly indicate that lupine flour exhibited higher antioxidant activity with DPPH and ABTS than the wheat flour. The conventional rheological studies of dough (Farinograph) show clear differences between wheat flour, lupine flour, lupine fiber and their blends. With increasing concentration of lupine flour or fiber, the viscoelastic properties were decrease. The dough blends demonstrated a deformation-dependent behavior and a distinctive linear viscoelastic behavior in the range of 10 ≤ γ ≤ 10. The curves slope of storage modulus G and loss modulus G'' nearly parallel in frequency sweep measurements for all concentrations, G was much greater than G'' this indicates the distinctive solid state characteristics of all dough’s and demonstrated that dough promoted dispersion and not gel-like structure. The level of G' and G" increase with increasing the lupine proportion. By the temperature sweep, simulated the bakery process, increase from 15 to 90 C can be detected the changes of material and process as denaturation of proteins, pre-and gelatinization of starch granules and the immobilization of water. A sensory acceptability of the bread or cake is satisfactory up to 10 % concentration of lupine flour or fiber given. Even though deterioration in the structural formation and a weakening of the gluten formation in the dough system after the addition of lupine flour or fiber were detected that the blends have relatively good viscoelastic behavior (viscoelastic properties will be maintained by the dominance of wheat) to bake acceptable, protein enriched consumable and bread. Finally, the addition of lupine flour or fiber reduced the blood glucose, total cholesterol and total lipid for diabetic rats. Lupine flour or fiber can be used successfully as hypoglycemic agents in bakery products. This could be utilized for the development of composite blends from locally produced lupine at small scale industry level as value-add products.