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Abstract
The water-holding capacities (WHC) of wheat flour when partially replaced with defatted soybean flour (DSF) or low-fat soybean flour (LSF) were evaluated. Wheat flour was replaced at 2, 4, 6, 8, 10, and 12% levels with DSF or LSF based on sample weight and/or soybean flour protein content. WHC (g water/g flour) was quantified after centrifuging hydrated samples at 1592×g (3,000 rpm) and/or 4,424×g (5,000 rpm) for 30 min. Results showed that at both centrifuge speeds, all wheat-soybean flour blends had WHC greater than wheat flour with the exception of 2% blends based on weight. Wheat-soybean flour blends had lower WHC at 5,000 rpm than at 3,000 rpm. In general, the WHC increased as the proportion of soybean flour increased. Differences in WHC were greatest between the samples containing 2 and 12% soybean flour. WHC values among the 6, 8 and 10% samples were not significantly different for both wheat-DSF and wheat-LSF blends. Blends containing LSF were observed to have comparable WHC to wheat-DSF blends.
Keywords Flour blends * Low-fat soybean flour * Water-holding capacity * Wheat flour
(ProQuest-CSA LLC: ... denotes formula omitted.)
Introduction
Flour blends are mixtures of cereal, root, or oilseed flours. The most commonly studied flour blends are made by partially replacing wheat flour with non-wheat flour. This practice arose from a need to increase the nutritional quality of wheat products, such as bread, that are consumed in developing countries. Soybean flour has been identified as a suitable complement to wheat flour for blends used in cereal-based products [1, 2] based on protein quality [3, 4]. This type of flour can compensate for the lysine deficiency of wheat flour. Wheat flour contains more sulfur-containing amino acids and is able to supplement the low amount present in soybean flour.
Soy protein products, such as soybean flour, are now staple ingredients in almost all food systems [5]. The prevalence of these protein products has been seen in bakery, meat, beverage, meat analog, and dairy items. The successful use of soy protein products in such diverse food applications can be attributed to the functional properties displayed by soy proteins. These proteins are known for such functional capabilities as fat binding, emulsification, gelling, foaming, viscosity, and water-holding.
Water-holding capacity (WHC) is an...