Partially defatted peanut flour: a functional ingredient to improve nutritional value of bakery products
Peanut seeds were used to obtain partially defatted peanut flour (PF) by means of a cross-flow solvent extraction process (n-hexane), using a continuous lixiviation apparatus. The chemical composition of PF showed high protein (410 g kg-1) and crude fiber (160 g kg-1) contents; total lipids (115 g kg-1) and minerals (47g kg-1) were in minor amounts. Physico-chemical properties of PF showed minimum solubility at pH 4 - 5 and maximum at pH 8. Water and oil holding capacities were 2.7 and 2.3 g ml-1, respectively, and presented emulsifying properties suitable for the formulation of bakery products. Breads prepared by replacement of 10 or 20 % wheat flour by PF showed significant increases of both protein and fiber contents, and improved fatty acid profile, with respect to breads made with wheat flour only Cookies made with PF had three times more protein content and nine times more fiber content than wheat flour-based cookies. The sensory scores of PF-based products were similar to those made with wheat flour. Partially defatted peanut flour provides a rich source of gluten-free protein, fiber and essential minerals. It may be used to enhance the nutritional quality of wheat flour-based bakery products.