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Envisioning Utilization of Super Grains for Healthcare
Published in Megh R. Goyal, Preeti Birwal, Santosh K. Mishra, Phytochemicals and Medicinal Plants in Food Design, 2022
The phytate degradation during fermentation is due to the production of phytase enzyme endogenously and exogenously by the microorganisms. Fermentation with Lactobacillus plantarum exhibits a phytate degradation of 83%–85% in quinoa and 64%–80% in amaranth thus improving the mineral bioavailability [38]. Similarly, Rhizopus oligosporus reduces the phytate of cooked quinoa grains by 72% after 40 h [59]. Iron, zinc, and copper bioavailability thus increases 3.5–4× and 1.7–2.5× in quinoa and amaranth, respectively, during fermentation [38]. Similarly, 49%–66% and 15% reduction in phytic acid and bound phenolic content occurs in teff leading to improved availability of iron and zinc [165].
Role of Lactic Acid Bacteria in Impacting Nutrient Bioavailability
Published in Marcela Albuquerque Cavalcanti de Albuquerque, Alejandra de Moreno de LeBlanc, Jean Guy LeBlanc, Raquel Bedani, Lactic Acid Bacteria, 2020
Sourdough fermentation degrades phytate by creating a favorable environment for the activity of both endogenous phytases in cereal grains as well as microbial phytases (D’Alessandro and De Pergola 2014, Schlemmer et al. 2009). This is how fermentation with LAB improves mineral bioavailability of grains. Bacterial activity during fermentation generates organic acids like lactic acid, that lowers the milieu pH, and this lower pH activates phytase (Katina et al. 2005, Schlemmer et al. 2009). A pH of 5.5 has been identified as both acceptable by consumers who dislike acidic tastes and the optimum pH for phytate degradation, as this is the pH at which endogenous plant phytase is most active (Reale et al. 2007). Unfermented plant material, in contrast, has a pH of around 7. LAB fermentation is, therefore, not directly responsible for phytate degradation but rather establishes conditions favorable for endogenous phytase activity, primarily through lowering the pH (Reale et al. 2007).
Covalent immobilization of phytase on the multi-walled carbon nanotubes via diimide-activated amidation: structural and stability study
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Mohammad Pooya Naghshbandi, Hamid Moghimi, Babak Latif
Figure 5 shows the pH (a) and temperature (b) profile relative activities of free and immobilized phytase. As expected, optimum pH of Escherichia coli phytase was in the range of 4.5–5.5. It was observed that the optimum activity of our phytase were in pH 5.5. Results shown that phytase activity decreased at both sides of the optimum pH 5.5 but there was a dramatically decline of enzyme activity at pH condition above 5.5. Retained about 66% and 30% relative activity at pH 6.5 and 7.5, while at pH 4.5 and 3.5 almost 91% and 68% of relative activity were retained, respectively, compared with that of the optimum condition. This reduction is because of a strong electrostatic repulsion which produced by the ionic groups within the phytase molecule in a strong alkaline pH media, leading to enzyme active centre change and the loss of enzyme activity, which is similar to studies [35–37]. The immobilized phytase optimum activity were shifted from pH 5.5 to 6.5 (towards more alkaline) which has similarity to immobilized 3,4-POD on f-MWNT compared to free one [26]. Interestingly, free phytase relative activity in pH 8–10 was lower than immobilized enzyme which is an indication of tendency of the enzyme to the alkaline environment. These results were similar to Dutta et al. which immobilized the phytase on magnesium nanoparticle. They showed that in addition to the shift of the pH optimum from 7.5 to 9, more resistant to the alkaline environment were obtained [38]. The effects might be due to MWNT properties and the environmental conditions which could affect the substrate to product conversion process.