Do Flavonoids from Durum Wheat Contribute to Its Bioactive Properties? A Prospective Study.

A clear gap with respect to the potential biological properties of wheat flavonoids exists in the available literature. This information is crucial for breeding programs aiming to produce new varieties presenting improved health benefits. Accordingly, advanced breeding lines of whole durum wheat were evaluated in this contribution. The highest recovery of phenolics was achieved using aqueous acetone (50:50, v/v), as verified by multi-response optimization, thus showing that phenolics could be largely underestimated by employing an inappropriate extraction. The concentration of derivatives of apigenin, the main phenolics present, ranged from 63.5 to 80.7%, as evaluated by LC-ESI-QTOF-MS. Phenolics from the breeding line 98 exhibited the highest ability in scavenging peroxyl radicals, reducing power as well as in terms of inhibition of pancreatic lipase activity, a key enzyme regulating the absorption of triacylglycerols. In contrast, none of the samples exhibited a significant anti-diabetic potential. Despite their high concentration compared to that of phenolic acids, results of this work do not support a significant antioxidant and pancreatic lipase inhibitory effect of durum wheat flavonoids. Therefore, breeding programs and animal and/or human trials related to the effect of durum wheat flavonoids on oxidative stress and absorption of triacylglycerols are discouraged at this point.

Parameters of the fermentation of soybean flour by Monascus purpureus or Aspergillus oryzae on the production of bioactive compounds and antioxidant activity.

The objective of this work was to evaluate the effects the solid-state fermentation parameters of defatted soybean flour (DSF) by Monascus purpureus or Aspergillus oryzae on the bioactive compounds. Central composite rotatable design, multi-response optimization, and Pearson's correlation were used. The fermentation parameters as initial pH (X1), DSF-to-water ratio (X2), and incubation temperature (X3) were taken as independent variables. The function responses were isoflavone content, total phenolic content (TPC), and antioxidant activity. All fermentation parameters affected the isoflavone content when fermented by Monascus purpureus, whereas the TPC or antioxidant activities remained almost unchanged. For the fermentation by Aspergillus oryzae, all the function responses were influenced by X2 and X3 and were independent of the X1. Estimated optimum conditions were found as x1 = 6.0, x2 = 1:1, and x3 = 30 °C for both fungi. Achieving suitable fermentation parameters is essential to increase bioactive compounds in the DSF that makes it promising for food industrial applications.

Soybean ultrasound pre-treatment prior to soaking affects ß-glucosidase activity, isoflavone profile and soaking time.

Ultrasound may convert conjugated isoflavones into their corresponding aglycones, the best form for absorption in the human body. However, ultrasound may also influence the activity of endogenous ß-glucosidase. Therefore, the present work evaluated the effects of soybean ultrasound pre-treatment by applying the Box-Behnken design prior to soaking, a step that is important for industries to prepare certain soy products. Furthermore, a multi-response optimisation is provided. The best conditions for soybean ultrasound pre-treatment were established as temperature, X1 = 55 °C; exposure time, X2 = 5 min and ultrasound intensity, X3 = 19.5 W cm-2. Under these conditions, soybeans with higher contents of aglycones were obtained and ß-glucosidase activity was kept as high as possible. A second experiment was conducted and confirmed that ultrasound pre-treatment results in a lower soaking time (2 h) to achieve the highest moisture content, lower hardness as well as increased content of aglycones.

Effects of ultrasound pre-treatment on the structure of ß-conglycinin and glycinin and the antioxidant activity of their hydrolysates.

The effect of power, time and temperature of ultrasound on the structure of ß-conglycinin (7S) and glycinin (11S), and on the antioxidant activity of their hydrolysates were investigated. All ultrasound treated 7S and 11S fractions showed an increase in the α-helix and ß-turn proportions, and a decrease in ß-sheet and random coil proportions. The polarity of 7S and 11S microenvironment increased after ultrasound treatment. Ultrasound treatment significantly increased the reduction capacity and iron chelating capacity of 7S and 11S hydrolysates. The degree of hydrolysis and free SH groups of 7S and 11S hydrolysates increased after ultrasound pre-treatment. The relative content of high molecular weight peptides reduced, and the relative content of low molecular weight peptides increased in ultrasound treated 7S and 11S hydrolysates. The ultrasonication exposed certain groups of 7S and 11S fractions, improved contact with enzymes, and increased the content of highly active soybean antioxidant peptides.

Multi-response optimisation of the extraction solvent system for phenolics and antioxidant activities from fermented soy flour using a simplex-centroid design.

A simplex-centroid design comprising three solvents (water, ethanol and methanol) was used to optimise the extraction mixture for phenolics and antioxidant activities from defatted soy flour fermented with Monascus purpureus or Aspergillus oryzae. Total phenolics were more efficiently extracted using only water for both samples. The highest antioxidant activities by the DPPH and ABTS methods were obtained using extraction mixtures containing at least 75 wt% water. Specific water:ethanol:methanol ratios promoted the joint optimisation of the total phenolic and isoflavone contents as well as antioxidant activities: 0.5:0.375:0.125 (wt/wt/wt) and 0.5:0.3:0.2 (wt/wt/wt) from defatted soy flour fermented with M. purpureus or A. oryzae, respectively. However, a water:ethanol ratio of 0.5:0.5 (wt/wt) was deemed optimal because it is comprised of green solvents and yielded results that were greater than 90% of the multi-response maximum values. Both the solvents and the sample matrix strongly influenced the extractability of total phenolics and isoflavones.