title: Content of Total Phenolics, Flavan-3-Ols and Proanthocyanidins, Oxidative Stability and Antioxidant Capacity of Chocolate During Storage.
abstract: Antioxidant (AO) capacity of chocolates with 27, 44 and 75% cocoa was assessed after production and during twelve months of storage by direct current (DC) polarographic assay, based on the decrease of anodic current caused by the formation of hydroxo-perhydroxyl mercury(II) complex (HPMC) in alkaline solutions of hydrogen peroxide at potentials of mercury oxidation, and two spectrophotometric assays. Relative antioxidant capacity index (RACI) was calculated by taking the average value of the AO assay (the sample mass in all assays was identical). Oxidative stability of chocolate fat was determined by differential scanning calorimetry. Measured parameters and RACI were correlated mutually and with the content of total phenols (Folin-Ciocalteu assay), flavan-3-ols (vanillin andp-dimethylaminocinnamaldehyde assay) and proanthocyanidins (modified Bate-Smith assay). During storage, the studied functional and health-related characteristics remained unchanged. Amongst applied AO assays, the DC polarographic one, whose validity was confirmed by two-way ANOVA and F-test, correlated most significantly with oxidative stability (oxidation onset temperature and induction time). In addition, principal component analysis was applied to characterise chocolate types.
authors.affiliation: Faculty of Agriculture, University of Belgrade, Nemanjina 6, RS-11081 Belgrade, Serbia.
authors.forename: Jovanka
authors.initials: J
authors.lastname: Laličić-Petronijević
authors.affiliation: Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6,  HR-10000 Zagreb, Croatia.
authors.forename: Draženka
authors.initials: D
authors.lastname: Komes
authors.affiliation: Institute of General and Physical Chemistry, Studentski trg 12/V, RS-11158 Belgrade 118, Serbia.
authors.forename: Stanislava
authors.initials: S
authors.lastname: Gorjanović
authors.affiliation: Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6,  HR-10000 Zagreb, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Belščak-Cvitanović
authors.affiliation: Institute of General and Physical Chemistry, Studentski trg 12/V, RS-11158 Belgrade 118, Serbia.
authors.forename: Lato
authors.initials: L
authors.lastname: Pezo
authors.affiliation: Faculty of Chemistry, University of Belgrade, P. O. Box 158, RS-11001 Belgrade, Serbia.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Pastor
authors.affiliation: Institute of General and Physical Chemistry, Studentski trg 12/V, RS-11158 Belgrade 118, Serbia.
authors.forename: Sanja
authors.initials: S
authors.lastname: Ostojić
authors.affiliation: Faculty of Science, University of Novi Sad, Trg Dositeja Obradovića 3, RS-21000 Novi Sad, Serbia.
authors.forename: Jovanka
authors.initials: J
authors.lastname: Popov-Raljić
authors.affiliation: Institute of General and Physical Chemistry, Studentski trg 12/V, RS-11158 Belgrade 118, Serbia.
authors.forename: Desanka
authors.initials: D
authors.lastname: Sužnjević
keywords: antioxidant capacity; chocolate; differential scanning calorimetry; oxidative stability; phenols; polarography