Experimental cookery

cold water extract the action of diastatic enzymes in converting starch to maltose was more rapid ; as a result, the rate of fermentation in bread mak- ing was increased. Alsberg has suggested adding some over-ground flour to flour reported low in diastase. Since the injured granules swell in cold water they absorb a larger proportion of water. Alsberg states that in the very severely over-ground flours the swelling may resemble heat gelatiniza- tion. Thus in severe over-grinding the baking quality is reduced although the hydration capacity of the flour is increased. Usually increased hydra- tion capacity means increased baking quality. Moderate over-grinding did not affect the gluten but evidence was found that severe over-grinding injured the gluten. Effect o£ Aging on Flour It is commonly accepted that aging, particularly during the first 4 or 5 weeks, improves the quality of flour for making bread. Dunlap has reported that he has always obtained better results with aged than with fresh flour. Some of his results are given in Table 46. TABLE 46 The Effects of Initial pH of Flour Upon Baking Results (Dunlap) Total minutes Volume Color, Tex- Value, ^H Acidity fermen- ture, cc. per cent per cent per cent tation Fresh 6.12 5.90 0.139 0.158 215 198 2160 2250 100 •103 100 102 100.0 Matured I 103.0 Matured II 5.69 0.178 186 2300 104 103 104.5 Matured III 5.48 0.198 173 2400 105 104 106.7 Matured IV 5.29 0.216 153 2520 106 105 100.2 Sherwood and Bailey report that loaf volume, color, and absorption improve during the first few months of aging, but the loaf volume may diminish after extended storage, even though the color and hydration capacity continue to improve. They found that proteolytic activity grad- ually decreased in storage, sprouted wheat flours retaining their activity in storage for a few years. The improvement in baking quality with aging has been ascribed to the increasing acidity, the increase in free fatty acids, and the diminution of proteolytic activity. Acidity. The acidity of flour increases in storage, the pH of aged being lower than that of freshly milled flour. However, Bailey believes that the increased acidity is not the only factor responsible for improve- EFFECT OF SALTS ON PROTEIN EXTRACTED 413 ment in baking strength, for, if this were the case, the baking quality could be improved by the addition of acids to doughs from fresh flours. Free fatty acids. Kozmin attributes the improvement w^ith aging to the development of free fatty acids. The removal of free fatty acids rejuvenated the flour, its bread-baking properties returning to their original state. In turn, the addition of free unsaturated fatty acids produces the same effect as natural aging. Unsaturated fatty acids had more effect than saturated ones. Aging or the development of free fatty acids occurred more rapidly as the storage temperature increased. Sullivan, Near, and Foley state that their results agree vrell vs^ith those of Kozmin, w^ith the exception that American flours do not show^ the im- provement w^hich European flours do w^ith the presence of free, unsaturated fatty acids. It vras found, however, that after oxidation of the unsaturated acids had occurred that the baking quality was seriously damaged.