title: Evaluation of non-thermal effects of electricity on anthocyanin degradation during ohmic heating of jaboticaba (Myrciaria cauliflora) juice.
abstract: This study investigated the non-thermal effects of electricity on anthocyanin degradation during ohmic heating of jaboticaba juice. For this, temperature profiles during conventional and ohmic heating processes were matched, and the degradation kinetics of anthocyanins were compared at temperatures ranging from 70 to 90°C. The monomeric anthocyanin content was quantified by UV-Visible spectroscopy using the pH-differential method. Anthocyanin degradation was fitted to a first-order model. The rate constants ranged from 1.7 to 7.5 × 10(-3)min(-1) and from 1.8 to 7.6 × 10(-3)min(-1) for ohmic and conventional heating, respectively. The analysis of variance (α=0.05) showed no significant differences between rate constants of the ohmic and conventional heating at the same temperatures. All kinetic and thermodynamic parameters evaluated showed similar values for both technologies. These results indicate that the presence of the oscillating electric field did not affect the degradation rates of anthocyanins during ohmic heating.
authors.affiliation: Institute of Food Science and Technology, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre, RS 91501-970, Brazil. Electronic address: giovana.mercali@ufrgs.br.
authors.forename: Giovana Domeneghini
authors.initials: GD
authors.lastname: Mercali
authors.affiliation: Nutrition Department, Federal University of Health Sciences of Porto Alegre, Rua Sarmento Leite, 245, Porto Alegre, RS 90050-170, Brazil.
authors.forename: Poliana Deyse
authors.initials: PD
authors.lastname: Gurak
authors.affiliation: Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, Porto Alegre, RS 90040-040, Brazil.
authors.forename: Frederico
authors.initials: F
authors.lastname: Schmitz
authors.affiliation: Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, Porto Alegre, RS 90040-040, Brazil.
authors.forename: Ligia Damasceno Ferreira
authors.initials: LD
authors.lastname: Marczak
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D004560:Electricity; D005504:Food Analysis / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D000067030:Fruit and Vegetable Juices / Q000032:analysis*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D027822:Myrtaceae / Q000737:chemistry; D009991:Oscillometry; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D000872:Anthocyanins
keywords: Electric field strength; Flavonoid compounds; Thermal treatment