Selection of lactic acid bacteria with high phytate degrading activity for application in whole wheat breadmaking

Whole wheat products although highly recommended from the nutritional point of view, contain high levels of phytic acid, an antinutrient that decrease the mineral bioavailability. The objective of this study was to select strains with high phytate-degrading activity from different parts of the gastrointestinal tract of chickens following a phytate-rich diet and to test their suitability for the breadmaking process of whole wheat bread. Different lactobacilli and bifidobacteria strains were isolated and individually assayed for phosphatase and phytase activities, since both enzymes could contribute to the degradation of phytate. The isolates showing the highest phytate degrading activity belonged to the species Bifidobacterium dentium, Lactobacillus reuteri (L-M15) and Lactobacillus salivarius (L-ID15). The two lactobacilli L-M15 and L-ID15 were selected and tested their fermentative ability in whole wheat breadmaking. Whole wheat breads in the presence of the selected lactobacilli had similar technological quality than the control (in absence of lactobacilli) and extended freshness; moreover, their presence resulted in bread crumbs with lower levels of inositol phosphates. Overall, the two intestinal lactobacilli strains showing high phytate degrading activity were proven to have good properties for being used as starters in whole wheat breadmaking process.