Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2012
Publication Date: 7/1/2012
Citation: Smith, B.M., Bean, S., Herald, T.J. and Aramouni, F. 2012. Effect of HPMC on the quality of wheat-free bread made from carob germ flour-starch mixtures. Journal of Food Science. 77(6):C684-C689.
Interpretive Summary: Gluten free breads typically suffer from poor quality and are typically produced from cake batter like systems rather from dough. This causes problems both in food quality and in food processing. Intense research has been focused on finding and developing non-wheat proteins that are capable of forming dough. This research optimized the use of a hydrocolloid in combination with carob germ flour to produce dough that handle similar to that of wheat dough. Breads made from this system had quality attributes similar to that of wheat bread. This research will benefit people with celiac disease and scientists working to improve the quality of celiac safe foods with other materials such as sorghum.
Technical Abstract: Carob germ proteins have been shown to have functional properties similar to wheat gluten enabling formulation and production of yeast leavened baked goods from a true dough rather than a stiff batter. The purpose of this research was to optimize the production of wheat-free bread containing carob germ flour, corn starch, NaCl, sucrose, hydroxypropyl methylcellulose (HPMC), and H2O. A key criterion was to formulate viscoelastic dough similar to wheat dough. To that end, response surface methodology (RSM) was used to determine optimal levels of carob germ flour, H2O, and HPMC. Components varied as follows: 4.94 – 15.05% for carob germ flour, 0.05 – 3.75% HPMC, and 65.25 – 83.75% water (percents are on a flour basis, where carob germ flour in combination with maize starch equal 100%). Sucrose, NaCl, and yeast were held constant at 2%. Bread parameters evaluated were specific volume and crumb hardness, where the largest specific volume and the lowest value for crumb hardness were considered most desirable. The optimum formula as determined by RSM consisted of 7% carob germ flour, 93% maize starch, 2% HPMC, and 80% water with predicted crumb hardness of ~200 g of force and a specific volume of ~3.5 cubic cm/g. When proof conditions were optimized, a specific volume of ~5.6 ml/g and crumb hardness value of ~156 g of force was observed. Carob germ flour may be used as an alternative to wheat flour in formulating viscoelastic dough and high quality gluten-free bread.