Effect of selected cereal flours on chemical composition, rheological properties and cake quality

THIS RESEARCH was carried out to substitute 10, 20 and 30% levels of wheat flour with rice, barley or yellow corn flour and their effects on rheological and baking properties, as well as, the acceptability of the cake. Water absorption increased by increasing the levels of rice flour. Meanwhile, development time, extensibility and energy were decreased. Dough Stability and maximum resistance to extension were gradually increased with increasing the replacement level with barley flour in comparison to control. The maximum viscosity value increased with addition of rice, barley or yellow corn flour. While, set-back values were decreased gradually with increasing the level of rice or barley flour. The results revealed that crude fiber, lipid and ash contents of cakes had gradually increased with increasing the levels of barley or yellow corn flours. Protein content was gradually increased with increasing the level of barley flour. Gradual improvement in both of cake weight and volume were noticed for cake samples prepared with rice or barley flour .The replacement of wheat flour by rice or barley flour retarded the rate of staling. This point was considered very important because of the major economic losses that stale bakery products may entail. The sensory evaluation data demonstrated that, the rice, barley or yellow corn flour successfully replace wheat flour in produced cake up to 20% without any unfavorable change

Characteristics of phytase in sunflower meal and broad beans

Properties of sunflower meal and cotyledon broad bean phytases were studied after extraction with 2% CaCl2 followed by ammonium sulphate partial purification. The enzyme showed an optimum pH of 4.0 and 4.2 respectively and optimum temperature of 45C for each phytases. The phytase of the tow extracts where partially inhibited at high substrate concentration, with an optimum substrate concentration at 9mM and 5mM respectively, and km value of 1.11 x 10-3M and 0.59 x 10- 3M. V max was 0.51 and 0.62 u mole P: liberated/min/ml enzyme respectively. The inactivation and activation energy for the hydrolysis of phytic acid were approximately 39.700 cal/mole and 9100 cal/mole respectively of sunflower phytase, whereas these values were 40.400 ca./mole and 11.300 cal/mole of bean phytase. The percentage of sunflower enzyme inhibition were about 28%, 24%, 36% and 48% in the presence of 10-3M zinc, cupric, ferrous and mercuric respectively. Also, these salts reduced phytase activity from bean by 25%, 20%, 20% and 28%, respectively