Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of kappa-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar ``Fuji'', cultivated in Sicily (Caltavuturo, Italy), inhibited kappa-casein fibril formation in a dose-dependent way. In particular, we found that the extract significantly reduced the protein aggregation rate and inhibited the secondary structure reorganization that accompanies kappa-casein amyloid formation. Protein-aggregated species resulting from the incubation of kappa-casein in the presence of polyphenols under amyloid aggregation conditions were reduced in number and different in morphology.
Valorization of Apple Peels through the Study of the Effects on the Amyloid Aggregation Process of kappa-Casein
Guarrasi Valeria;Costa Maria Assunta;Librizzi Fabio;Vilasi Silvia
2021
Abstract
Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of kappa-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar ``Fuji'', cultivated in Sicily (Caltavuturo, Italy), inhibited kappa-casein fibril formation in a dose-dependent way. In particular, we found that the extract significantly reduced the protein aggregation rate and inhibited the secondary structure reorganization that accompanies kappa-casein amyloid formation. Protein-aggregated species resulting from the incubation of kappa-casein in the presence of polyphenols under amyloid aggregation conditions were reduced in number and different in morphology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.