Complexes of amylose or high-amylose corn starch (HACS) with genistein were prepared by the acidification of an alkali solution to yield a V 6IotaIotaIota structure. The amylose-genistein complexes exhibited significantly higher genistein content (11 mg/100 mg of complex) than HACS-genistein complexes (9 mg/100 mg of complex). The effect of genistein on the amylose complexes was examined in different genistein-amylose ratios, and a model for genistein organization in the amylose complexes was suggested. The complexes were stable at different pH values, with <10% of the complexed genistein released, and were stable at 30 and 50 degrees C. Lower stability was observed at 80 degrees C as shown by the extensive release of genistein. All complexes showed high retention of genistein in simulated stomach conditions and released genistein upon digestion in pancreatin solution. It is therefore suggested that the complexes can be used as carriers for the slow release of genistein.

Carrageenan (CGN), a family of marine polysaccharides isolated from seaweeds, has been at the heart of considerable debate in recent years. To date, CGN is generally recognized as safe based on a history of safe use, various acute toxicology studies and some recent chronic toxicology tests. This review offers readers an overview of evidence on CGN characteristics and digestive fate that highlight various gaps in our understanding. Specifically, three unresolved gaps are identified. Firstly, little information can be found on the current levels of public exposure to CGN. Secondly, the link between CGN physicochemical properties, its impact on digestive proteolysis, the colon microbiome and inflammation are yet to be fully resolved. Thirdly, scant scientific evidence exists on the differential digestive fate of CGN in the gut of liable and predisposed populations, such as elderly people or IBD patients. Altogether, revisiting the scientific evidence indicates that more research is needed to elucidate the possibility that continued exposure to increasing levels of CGN in the human diet may compromise human health and well-being.

Soy isoflavones, present in many processed soy foods, are known for their phytoestrogenic and antioxidant activities. The aim of this work was to study the kinetics of genistein and daidzein degradation at elevated temperatures and to follow changes in their antioxidant activity. Daidzein and genistein in model solutions (pH 7 and 9) were thermally treated at 120 degrees C or incubated at 70, 80, and 90 degrees C. Isoflavone degradation was observed at all temperatures, with apparent first-order kinetics at 70-90 degrees C, and E(a) = 8.4 and 11.6 kcal/mol at pH 9, respectively. Microcalorimetric stability tests showed a similar pattern of degradation, however, with higher E(a) (genistein, 73.7 kcal/mol; daidzein, 34.1 kcal/mol) that may be attributed to the anaerobic conditions. The antioxidant activity of incubated isoflavone solutions, followed by the ABTS test, decreased rapidly at pH 9 for genistein, whereas only moderate reduction was observed for daidzein (pH 7 and 9) or genistein at pH 7. This may indicate different degradation mechanisms for genistein and daidzein.

Soy isoflavones are widely recognized for their potential health benefits. The increased use of traditional and new food products calls for the assessment of their stability during processing and storage. The present study examines the stability of genistein and daidzein derivatives in soy milk. Soy milk was stored at ambient and elevated temperatures, and the change in isoflavone concentration was monitored with time. Genistin loss in time showed typical first-order kinetics, with rate constants ranging from 0.437-3.871 to 61-109 days(-1) in the temperature ranges of 15-37 and 70-90 degrees C, respectively. The temperature dependence of genistin loss followed the Arrhenius relation with activation energies of 7.2 kcal/mol at ambient temperatures and 17.6 kcal/mol at elevated temperatures. At early stages of soy milk storage at 80 and 90 degrees C, the 6' '-O-acetyldaidzin concentration increased, followed by a slow decrease. The results obtained in this study can serve as a basis for estimating the shelf life of soy milk as related to its genistin content.

No abstract