title: Yeast mannoproteins improve thermal stability of anthocyanins at pH 7.0.
abstract: Anthocyanins are food colourants with strong antioxidant activities, but poor thermal stability limits their application in neutral foods. In the present study, impacts of yeast mannoproteins on the thermal stability of anthocyanins were studied at pH 7.0. The degradation of anthocyanins at 80 and 126 °C followed first order kinetics, and the addition of mannoproteins reduced the degradation rate constant and increased the half-life by 4 to 5-fold. After heating at 80 and 126 °C for 30 min, mannoproteins improved the colour stability of anthocyanins by 4 to 5-fold and maintained the antioxidant capacity of anthocyanins. Visible light absorption, fluorescence spectroscopy, and zeta-potential results suggest that anthocyanins bound with the protein moiety of mannoproteins by hydrophobic interactions, and that the inclusion of anthocyanins in complexes effectively reduced the thermal degradation at pH 7.0. Therefore, mannoproteins may expand the application of anthocyanins as natural colours or functional ingredients.
authors.affiliation: Hubei Collaborative Innovation Center for Processing of Agricultural Products, Wuhan Polytechnic University, Wuhan 430023, China; Department of Food Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Jine
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Food Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Yongguang
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Food Science and Technology, The University of Tennessee, Knoxville, TN 37996, USA. Electronic address: qzhong@utk.edu.
authors.forename: Qixin
authors.initials: Q
authors.lastname: Zhong
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D000975:Antioxidants / Q000494:pharmacology; D003116:Color; D005656:Fungal Proteins / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008562:Membrane Glycoproteins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; C025363:mannoproteins
keywords: Anthocyanins; Antioxidant capacity; Complex formation; Mannoproteins; Thermal stability