dure may have an important effect on protein conformation and hydrophobicity. The WHC of PF obtained by using the process described in this study was 2.7 ml g-1 flour (table 2). This represents a value higher than those from peanut flour obtained by other methods (30 - 32). 384 Fat absorption capacity (FAC). The ability of proteins to bind lipids is related to flavor retention capacity, and it is important for making edible products. Even though PF contained natural oil (115 g kg-1), externally added oil was well absorbed. The FAC value found in PF was 2.3 ml g-1 flour (table 2). It was similar to values reported by other authors (30) for unfermented raw and roasted peanut flour, and higher than those informed by Juliana and Zhengxing (31) and Joshi et al. (32). Emulsion properties. Flours with good emulsifying activity (EA) may enhance physical properties of bakery products by reducing water losses during baking and improving bread texture. Values of EA and emulsion stability (ES) from PF were 0.7 and 92 s, respectively (table 2). The former was lower and the latter was higher than values reported elsewhere (25, 31). Emulsion properties observed in PF may be attributed to two main reasons: proteins reducing surface tension of oil droplets, and carbohydrates stabilizing the emulsion by increasing viscosity. Chemical composition of breads and cookies Chemical composition of breads is showed in table 1. The bread made with 10 % peanut flour (PFB1) had 124 g kg-1 protein. An increment of 10 % PF in bread formulation raised the total protein content by about 3 %, so that bread prepared with 20 % peanut flour (PFB2) contained almost twice as much protein (156 g kg-1) as the 100 % wheat flour-based bread (WB) (84 g protein kg-1). The use of PF also increased markedly the crude fiber content (up to six times when 20 % PF was used) in relation to breads made with wheat flour only. Fatty acid profiles were also improved. In wheat flour-based bread, the FA composition reflected greatly that of the butterfat, whereas in breads added with PF the contribution of peanut oil increased oleic and linoleic acid contents and enhanced unsaturated/saturated fatty acid ratio. Mineral composition was similar between the varieties of breads. Potassium was the most abundant mineral, followed by magnesium and calcium. Composition of micro minerals showed the major levels of FIGURE 1 Protein solubility profile of peanut flour. 1 2 3 4 5 6 7 8 9 10 11 pH TABLE 2 Functional properties of peanut flour (PF). 35 30 25 20 15 10 5 0 Protein solubility (g.100 g-1 of flour) Functional properties PF Protein solubilitya 26.48 ± 0.42 Water holding capacity (ml g-1 flour) 2.7 ± 0.03 Oil absorption capacity (ml g-1 flour) 2.3 ± 0.31 Emulsifying activity (s) 0.7 ± 0.08 Emulsion stability (s) 92 ± 0.11 Mean values ± standard deviations (s(n-1)), n=3. aPercentage of soluble protein in 0.01 M Na2HPO4 solution at pH 7. (s) Seconds. Labuckas D. y cols.
Rev Nutr 43-4
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