Abstract
Preparations of 6-phytase A (EC 3.1.3.26) and phytase B (acid phosphatase, EC 3.1.3.2) were applied alone and combined in the preparation of dough to estimate their catalytic potential for myo-inositol liberation from rye flour in the breadmaking technology. The experimental bread samples were ground after baking and subjected to determination of myo-inositol bioavailability by an in vitro method that simulated digestion in a human alimentary tract, followed by measurements of myo-inositol transport through enterocyte- -like differentiated Caco-2 cells to determine its bioaccessibility. Myo-inositol content was measured by a high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) technique. The concentration of myo-inositol in the dialysates of control bread was 25.3 µg/mL, whereas in the dialysates of bread sample baked with 6-phytase A, the concentration increased to 35.4 µg/mL, and in the bread baked with phytase B to 64.98 µg/mL. Simultaneous application of both enzymes resulted in myo-inositol release of 64.04 µg/mL. The highest bioaccessibility of myo-inositol, assessed by the measurement of the passage through the Caco-2 monolayer was determined in the bread baked with the addition of 6-phytase A. Enzymatically modified rye bread, particularly by the addition of 6-phytase A, may be therefore a rich source of a highly bioaccessible myo- -inositol.
Highlights
Phytic acid (1,2,3,4,5,6-myo-inositol hexakisphosphate) is difficult to digest in the gastrointestinal tract of monogastric animals and humans, and is considered as an antinutritional factor because it reduces bioavailability of minerals, proteins and starch [1]
Loaves of rye bread baked from dough samples with the addition of either 6-phytase A (5000 PAU per kg of flour) or phytase B (30 APAU per kg of flour), or a combination of 6-phytase A with phytase B were analyzed by the in vitro procedure that simulated gastric and intestinal digestion in humans to assess bioavailability of myo-inositol
In samples of control bread baked without enzymes the concentration of dialysable myo-inositol was 25.3 μg/mL, in the dialysates of bread baked with 6-phytase A 35.49 μg/mL, whereas in bread supplemented with phytase B, myo-inositol concentration was almost 2.56-fold higher (64.98 μg/ mL)
Summary
Phytic acid (1,2,3,4,5,6-myo-inositol hexakisphosphate) is difficult to digest in the gastrointestinal tract of monogastric animals and humans, and is considered as an antinutritional factor because it reduces bioavailability of minerals, proteins and starch [1]. Phytases A are not able to hydrolyse phosphate residue at the C2 of the myo-inositol ring. Okazaki and Katayama [15] found that myo-inositol prevented accumulation of fat in the liver of rats intoxicated with DDT This compound regulates fat metabolism in the myocardium of rats with chemically induced diabetes [16]. Some reports indicate that mixtures of myo-inositol and phytate are more effective in cancer cell elimination than these substances administered separately [19,20]. The strategy presented here is based on the concept of enzymatic conversion of endogenous phytates of rye flour into myo-inositol by means of commercial microbial phytases added to the dough. Phytase application in the breadmaking has been studied by a few researchers [57,21], there is no evidence to suggest that this can be utilized as a method for producing bread with enhanced myo-inositol content
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
