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 hydroxypropylmethylcellu lose (HPMC) on wheat dough performance have been studied. Effects of hydroc olloids added singly and in association at different levels, on the investi gated 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 obs erved on both the gluten index (GI) and the energy of dissociation of the a mylose-lipid complex (Delta H-x). Optimized dosage of 1.36 g GNFZ/100 g flo ur, 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 predict ors of the quality of fresh and stored formulated breads to be obtained. Th e strengthening effect of high ester pectin was reinforced by the negative quadratic effect of GNFZ on gluten extensibility, the positive effect of GN FZ/HPMC on the resistance to extension of gluten, and the negative synergis tic 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 b ecause of the reduction of the induced degree of softening during mixing (f arinograph) of GNFZ formulated doughs. A dosage of 0.109 g XANTHAN/100 g fl our annulate the softening effect of GNFZ when added at an optimized dose o f 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 comp lexation. Addition of HPMC at a level < 1/ > 1 moderate/enhance, respective ly, the effect of GNFZ on the resistance to extension of the gluten, and th e 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.