In Vitro Solubility of Calcium, Iron, and Zinc in Rice Bran Treated with Phytase, Cellulase, and Protease

Abstract

Absorption of minerals is inhibited by phytic acid, fiber, and protein because of the chelates formed. Response surface method (RSM) was used in this study to evaluate the effect of application of commercial phytase, protease, and cellulase in rice bran on the in vitro solubility of calcium (IVCa), iron (IVFe), and zinc (IVZn). It is shown that IVCa and IVZn were significantly improved by the application of phytase and cellulase, and the models of two second-order polynomials are recommended for prediction, with coefficients at R(2) = 0.86 and R(2) = 0.88, respectively. Interaction between protease and cellulase also significantly affected IVCa and IVZn. Cellulase had more efficiency than phytase on IVCa. Differing in its effect on Ca and Zn, phytase had a significant linear correlation with IVFe, and none of the other processing parameters exerted a significant effect. The largest increment for IVFe, IVCa, and IVZn occurred in the treatment with applications of phytase at 2.5 U g(-1) and protease and cellulase at 0.2% and 1%, respectively, which were 3.3, 3.6, and 4.3 times, respectively, that of the untreated material.

Phytase‐mediated mineral solubilization from cereals under in vitro gastric conditions

“…25,26 Concerning rice bran and sorghum, no other studies investigating the phytase catalysis in the actual simulated gastric conditions were found. However, phytase pretreatment of rice bran increased Fe and Zn solubility in an in vitro digestion model 46 to a magnitude similar to what was found in the present study. For sorghum, activation of endogenous phytases during germination (although not being directly comparable with the simulated digestion of the present study) resulted in 25-35% phytate removal, in turn increasing Zn dialyzabilities to values similar to the solubilities reported in the present study and Fe dialyzabilities to a lower extent than the solubilities reported in the present study.…”

Does the pelleting process affect the nutritive value of a pre‐starter diet for suckling piglets? Ex vivo studies on mineral absorption

“…Zn is probably the most susceptible mineral to phytate complexation, an effect that is aggravated in the presence of Ca through the formation of insoluble calcium phytate–zinc complexes 47. It is known that hydrolysing phytate, either by the addition of enzymes like phytase48 or by thermal processing such as extrusion,42 increases the bioavailability of minerals, as a result of the release of the mineral–phytate complex and a greater mineral solubility 49. Therefore, a possible positive effect of phytate hydrolysis on mineral availability due to the heat treatment applied during the pelleting process cannot be discarded.…”

Enzymatic degradation of phytate, polyphenols and dietary fibers in Ethiopian injera flours: Effect on iron bioaccessibility

“…For treatment with xylanase + cellulase (X + C), 0.014 g ($50 U) of xylanase and 8 ll of cellulase (6.8 EGU) were added to the dephytinised flour, and the mixture was incubated in a shaking water bath at 35°C for 3 h. The amount of cellulase to be added was based on the optimisation of Wang et al (2008). For treatment of dephytinised flour with polyphenol oxidase (PPO), NaOH was added until the pH reached pH 6.5, the optimum for PPO activity, and 0.1 mol/l MES (2-(N-morpholino) ethanesulphonic acid-M8250) buffer was added to achieve a final flour:buffer ratio of 1:10 (w/v).…”

“…However, the degradation did not improve iron in vitro bioaccessibility (Baye, Mouquet-Rivier, Icard-Vernière, Picq, & Guyot, 2014), suggesting that either more iron-binding phenolic compounds need to be removed or that other factors, such as fiber, were responsible for the low bioaccessibility of iron in vitro. Applying exogenous enzymes to disrupt the food matrix could be an effective way of assessing the relative effects of different iron absorption inhibitors, which would make it possible to better target the inhibitors and to increase their degradation (Lestienne et al, 2005;Matuschek et al, 2001;Wang, Cheng, Ou, Lin, & Liang, 2008 reported in previous studies, little or no information was provided on the extent of the degradation of the targeted absorption inhibitors. This is unfortunate, since iron bioaccessibility does not only depend on the type but also on the amount of absorption inhibitors that remain in the foods.…”