The content of polyphenols and the antioxidative properties were determined in soybean tempeh fermented by four strains of Rhizopus oligosporus. The highest concentration of polyphenols was observed in soybean fermented for 4 days by R. oligosporus strain NRRL 5905 (5.307 mg/g). The strength of antioxidative activity increased from the first day of fermentation to the fourth day, and on the fourth and fifth fermentation day it was near 12 times higher than in unfermented material. Isoflavone content and composition were analysed. The content of isoflavone aglycones (daidzein and genistein) increased up to the third day of fermentation. Fermentation time and the kind of used R. oligosporus strain are factors that enable creation of prohealthy quality of tempeh.

L-3,4-dihydroxyphenylalanine (l-DOPA) is a medically relevant compound in Parkinson’s disease therapy. Several extraction methods of l-DOPA from beans, including velvet and faba beans, have been described in the literature. However, these methods require the use of strong acids, long extraction times, or complex downstream processing, which makes the extraction of l-DOPA expensive and energy-demanding, limiting its industrial application. In addition, the stability of l-DOPA during the extraction process is critical, further complicating the extraction of adequate amounts of this amino acid. This work is the first report on a simple, rapid, greener, and robust extraction method of l-DOPA. The developed method consists of a quick homogenization step followed by a double extraction with 0.2% v/v acetic acid for 20 min and was applied to faba bean at a ratio of 1:25 with respect to the extracting solvent. This study also investigated the stability of l-DOPA during extraction and thermal treatment. The proposed method demonstrated to be robust and extraordinarily efficient for numerous cultivars of faba bean, velvet bean, and food products containing faba beans.

The increasing demand for cocoa and search for ingredients rich in bioactive compounds encouraged us to investigate the possibility of replacing it by carob powder in the muffins containing soy beans, sesame oil and flaxseeds. There was 5% addition of carob or cocoa powder to the individual doughs. The muffins with the addition of carob were characterized by improved antiradical activity (by 36% - 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) method, by 83% - 2,2-diphenyl-1-picrylhydrazyl (DPPH) method), higher content of genistein (18%) and total phytosterols (17%) in the dry mass. The color differences in the carob muffins crusts were not perceptible by consumers (ΔE = 0.70 for crust, ΔE = 5.6 for crumb) and their taste was found to be less bitter and sweeter than the taste of cocoa muffins. Moreover, the addition of carob powder as well as cocoa powder resulted in good sensory quality. The high content of phytosterols, genistein and improved antiradical properties proved carob to be a source of bioactive compounds. The results show that carob powder may be used as valuable alternative muffin ingredient to cocoa.

In this study the effect of bean tempeh on the growth of Bacillus subtilis, Escherichia coli, Lactobacillus acidophilus and Lactobacillus paracasei bacteria was investigated. Antibacterial activity was observed only in relation to the bacteria Bacillus subtilis. The effect of tempeh products on human intestinal microflora was also assessed. Bean and soy tempeh were culinarily processed and next digested in conditions simulating the human digestive tract (one of the digestive tracts was equipped with a mechanism simulating absorption). Soy tempeh stimulated most the growth of bacteria of the genus Bifidobacterium, while bean tempeh that of Escherichia coli. Using simulation of absorption for the digestion of fried soy tempeh resulted in a higher rise in the bacteria count of the genus Lactobacillus, while after digestion of fried bean tempeh the highest increase was recorded for Bifidobacterium and E. coli.