Optimization of hydrocolloid addition to improve wheat bread dough functionality:: a response surface methodology study

Effects of high ester pectin + alpha-amylase + sucrose (GNFZ), a high ester pectin + sucrose (BIG), xanthan gum (XANTHAN) and hydroxypropylmethylcellulose (HPMC) on wheat dough performance have been studied. Effects of hydrocolloids added singly and in association at different levels, on the investigated rheological, mechanical and thermal parameters have been evaluated by response-surface methodology. Optimum hydrocolloid formulations for white wheat bread are recommended. Positive linear and negative quadratic significant effects of GNFZ were observed on both the gluten index (GI) and the energy of dissociation of the amylose-lipid complex (Delta H-x). Optimized dosage of 1.36 g GNFZ/100 g flour, d.b. (maximum of the respective response surface plot) led to maximized values for both GI and Delta H-x, described as good indicators and predictors of the quality of fresh and stored formulated breads to be obtained. The strengthening effect of high ester pectin was reinforced by the negative quadratic effect of GNFZ on gluten extensibility, the positive effect of GNFZ/HPMC on the resistance to extension of gluten, and the negative synergistic effect of the pair BIG/HPMC on dough extensibility. XANTHAN when added singly induced desirable increase in dough resistance to extension, and the incorporation of the pair XANTHAN/GNFZ into dough formula is recommended because of the reduction of the induced degree of softening during mixing (farinograph) of GNFZ formulated doughs. A dosage of 0.109 g XANTHAN/100 g flour annulate the softening effect of GNFZ when added at an optimized dose of 1.36 g GNFZ/100 g flour. Caution should be applied when added XANTHAN in presence of BIG because of the decrease in the extent of amylose-lipid complexation. Addition of HPMC at a level < 1/ > 1 moderate/enhance, respectively, the effect of GNFZ on the resistance to extension of the gluten, and the water binding capability of BIG, and in this respect the incorporation of the cellulose derivative is encouraged at a dose dependent on the required effect. (C) 1999 Elsevier Science Ltd. All rights reserved.