Driven by their beneficial effects on human metabolism, isoflavonoids have gained considerable importance reflected by an increased number of isoflavone-rich foods, food supplements and pharmaceutical products on the market, mainly derived from soy and red clover. While it is well known that the genuine isoflavone pattern will be altered during processing, data on aglycone stability are rare. Therefore, a thorough study into the thermal sensitivities of biochanin A, daidzein, formononetin, flavone, genistein, glycitein and isoflavone was performed. Samples were heated at 150 degrees C over a period of 7 h at three different pH values, and degradation of the aglycones was monitored by HPLC-DAD analyses. Therefrom, structure-related stability characteristics could be established. While virtually no decay was observed at pH 7.0 and 5.6, degradation was most prominent at pH 3. 1. Individual aglycone retention was further dependent on heating time with daidzein being the most labile compound after any time interval. Curve fitting of the data revealed first-order degradation kinetics for flavone and glycitein, while the remaining aglycones exhibited a sigmoidal degradation pattern.

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Parametric optimization of the laser-assisted photocatalytic growth of Ag and Au nanoparticles for high SERS enhancement factor performance informed by design of experiment is demonstrated. The photodeposition process was divided into two phases –seeding and growth– in order to achieve the highest possible nanoparticle surface coverage for the size range from 10 to 100 nm. A substantial difference in the parameter effects between the Ag and Au seeding and growth was found. The SERS performance of the photodeposited Ag and Au nanostructures was evaluated at 532, 633 and 785 nm with thiophenol as a probe molecule. A high-enhancement broadband SERS operation was attained with Ag nanostructure grown at high laser fluences. The SERS enhancement factors of 105 were achieved with both Ag and Au nanostructures.

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