Effect of proofing time and wheat flour strength on bleaching, sensory characteristics and volume of French breads added with soybean

• Grant number: 07/05536-5
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: September 01, 2007
• End date: October 31, 2007
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Inar Castro Erger
• Grantee: Inar Castro Erger
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Soybean lipoxygenase addition in wheat bread doughs is widely used to improve crumb color and rheology, but little is known about the variability of the activity of lipoxygenase under diverse breadmaking conditions. Thus, the objective of this study was to evaluate how soybean lipoxygenase can affect bleaching, volume and sensory characteristics of French breads when proofing time and wheat flour strength varies. A 3-factor Box-Behnken design was used in this study containing one block and three independent variables or factors designated by exogenous lipoxygenase activity [...], wheat flour deformation energy (x2= 231 - 258 x 10-4 J) and proofing time (x3= 2-6 h). Breads were randomly prepared and all assays were repeated three times. Specific volume [...], sensory quality [...] and yellow hue [...] significantly changed (p<0.01) among the treatments. Specific volume of the breads increased with higher values of wheat flour strength and proofing time ( vs= 7.5 + 0.9 x2 + 1.2 x3 +0.5 x2x3). Sensory quality improved at higher values of wheat flour strength and shorter proofing time ( sq = 7.8 + 0.7 x2 -0.2x3 -0.4x22-0.6x32 + 0.5 x2x3), while lower and more desirable values of yellow hue were achieved at longer proofing time, higher activity of lipoxigenase and using stronger wheat flours ( b = 13.7 -1.2x1 -0.5x2 -0.2x3 + 1.0x12 -0.3 x1x2). All regression models showed a good fitness to the experimental data (lack of fit, p > 0.05) and the difference between predicted and observed values were also not significant (p<0.05). Our results suggested that proofing time and wheat flour strength have a greater effect on volume and sensory quality of French breads than soybean lipoxigenase. However, the bleaching effect of this enzyme showed positive interaction with proofing time and wheat flour strength, suggesting its application even when strong wheat flours are used for French breads manufacture. (AU)