Phytate content is reduced and β-glucanase activity suppressed in malted barley steeped with lactic acid at high temperature

The effect of different steeping conditions on phytate, β-glucan and vitamin E in barley during malting was studied by a full factorial experiment with three variables (steeping temperature, barley variety and steeping additions). Addition of lactic acid to the steeping water induced a reduction of phytate during steeping and germination, especially in combination with the high steeping temperature (48°C). Furthermore, lactic acid and high temperature steeping inhibited β-glucanase development, resulting in a well-preserved β-glucan content after germination. When steeping was conducted without addition of lactic acid, the low steeping temperature (15°C) promoted development of both phytase and β-glucanase activity during germination. A slightly higher level of tocopherols and tocotrienols was observed in samples steeped at 15°C than in samples steeped at 48°C. However, addition of lactic acid reduced the amount for both temperatures. When lactic acid bacteria were added to the steeping water none of the parameters studied differed from samples steeped with water only. The results show the possibility of combining phytate degradation with a preserved β-glucan content during malting and can thus be of interest for development of cereal products with improved nutritional value.