Determination of the Dependence of Thermal Diffusivity with Moringa Concentration by Thermal Lens as a Sensitive Experimental Technique

Photoacoustic characterization of wheat bread mixed with Moringa oleifera

Photoacoustic spectroscopy is applied to evaluate the impact of Moringa at different concentrations (0, 1.25, 2.5, 5 and 10%) on the elaboration, sanity, texture, and color of wheat bread. It was found that: i) Photoacoustic signal amplitude values of bread significantly increase from 37 to 90% when moringa powder concentration raises from 1.25% to 10%, at 300 nm wavelength. ii) Comparing the photoacoustic signal values at 300, 330, and 370 nm wavelengths, produced by the different bread types, there were statistically significant differences. iii) The sanitary quality of bread mixed with a 2.5% of moringa is relatively higher than the ones obtained for other concentrations, such that the number of fungal colonies were reduced by 99% in comparison with the control bread without moringa, after six days of storage. Moringa at 2.5% of concentration could thus improve the sanitary quality of wheat bread. iv) The addition of moringa for making bread slows down its textural changes (hardness, elasticity, cohesiveness, resilience, and chewiness) during storage. v) Finally, the highest correlation between the photoacoustic amplitude and the moringa concentration occurs at the wavelengths of 300 and 330 nm, which could be related to significant changes in the content of flavonoids and phenolic acids.