COMBINED USE OF ISPAGHULA AND HPMC TO REPLACE OR AUGMENT GLUTEN IN BREADMAKING

Bread with a degree of aeration in the range typical of commercial wheat bread (approximately 4.5 ml/g) has been produced from rice flour (which is devoid of gluten) by the combined use of two polysaccharide structuring-agents: hydroxypropyl-methylcellulose (HPMC) and isabgol (the milled seed husk of Plantago ovata Forsk, alternatively known as ispaghula or blond psyllium). Isabgol gives a 'weak gel' network which traps carbon dioxide generated during proofing, and HPMC maintains the stability of gas cells at oven temperature. Optimum results were obtained using 10 g isabgol, 20 g HPMC (K4M from Dow), 60 g fat, 50 g sugar, 15 g salt, 10 g dried yeast and 812 ml water per kg of rice flour, with 50 min proofing in an oven set at 65-70-degrees-C (giving a final temperature of 40-degrees-C in the centre of the dough), and a baking period of 30 min at 230-degrees-C. The water content proved critical, with higher levels giving large cavities in the bread. Taste-panel evaluation gave a hedonic rating of approximately 7 on a 9-point scale. When used with soft-wheat flour, the isabgol-K4M system gave loaf volumes close to that of a hard-wheat control.