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Anthocyanins are very spectacular plant pigments with many biological activities. However, because of their highly reactive nature, anthocyanins are unstable. We developed a novel strategy for improving the thermal stability and photostability of cyanidin-3-O-glucoside (C3G) molecules by encapsulating them within the inner cavity of apo recombinant soybean seed H-2 subunit ferritin (rH-2). C3G molecules were successfully encapsulated within protein cages with a C3G/protein ratio of 37.5 to 1. As expected, such encapsulation increased the thermal stability and photostability of C3G molecules by a factor of ~2. More importantly, Caco-2 cell monolayer absorption and adhesion analyses showed that C3G molecules encapsulated within apoferritin nanocages were more efficient in transport as compared to free C3G. These findings indicate that protein with a shell-like structure as a nanoplatform can play an important role in the field of nutrition. [ABSTRACT FROM AUTHOR]

Abstract: Biofortification with phytoferritin is considered as a promising approach to the eradication of iron deficiency anemia. However, phytoferritin is not stable enough to be against degradation by protease(s) in the gastrointestinal tract, thereby leading to its low bioaccessibility. Fortunately, binding of proanthocyanidins (PAs) to protein offers the opportunity to prevent phytoferritin from degradation by the protease(s). To test this idea, the interaction of PAs from grape seeds with soybean seed ferritin (SSF) was studied using a combination of fluorescence, CD spectra, stopped-flow light scattering (SLS), and dynamic light scattering (DLS). Results showed that PAs can indeed bind to SSF in a dose-dependent manner. Consequently, such binding can significantly inhibit the degradation of SSF by the protease(s) in simulated gastric fluid (SGF) at pH 4.0 when the mass ratio of PAs to SSF is more than 1:1. Similarly, the stability of SSF in simulated intestinal fluid (SIF) was also increased upon treatment with PAs. These findings raise the possibility that the bioaccessibility of phytoferritin to the gastrointestinal tract was improved in the presence of proanthocyanidins. [ABSTRACT FROM AUTHOR]

Abstract: Two new pyrrole derivatives 2-(1H-pyrrol-1-yl)succinic acid (P-Asp) and 2-(1H-pyrrol-1-yl)pentanedioic acid (P-Glu) were synthesized to study their effect on garlic greening, the structures of which are similar to that of a previously proposed pigment precursor for garlic greening. The puree of freshly harvested garlic bulbs turned green after being soaked in solutions of the two compounds. Also, it was found that yellow pigments can be produced by reacting the two model compounds with pyruvic acid at room temperature. Four major new yellow pigments from these two model systems were formed. Two of them named AUP-1 and AUP-2 produced from model system II consisting of P-Asp and pyruvic acid have the same molecular weight 417.1294 [M+H]+ but having different retention times in HPLC, suggesting that there are isomers with each other. Likewise, other two isomer compounds GUP-1 and GUP-2 from model system I containing P-Glu and pyruvic acid have molecular weight as 445.1586 [M+H]+. The molecular formula for AUP-1 and AUP-2 was C20H20N2O8 while the molecular formula for GUP-1 and GUP-2 was C22H24N2O8. All these results confirmed previous proposal that pyrrole derivatives acted as PP (pigment precursor) for Allium discoloration. [Copyright &y& Elsevier]