title: Near-Infrared Spectroscopic Analysis of Total Phenolic Content and Antioxidant Activity of Berry Fruits.
abstract: This study evaluates the feasibility of using near-infrared (NIR) spectroscopy as a rapid and environmentally friendly technique for validation and prediction of the total phenolic content (TPC) and antioxidant activity (AOA) indices (as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, inhibition time (IT) of the Briggs-Rauscher oscillating reaction, and relative antioxidant capacity (RAC)) of berry fruit extracts. The analysed berry samples originated from Croatia (blackberries, wild blueberries, raspberries, red currants and strawberries) and Bulgaria (wild blueberries, raspberries and strawberries). Principal component analysis and partial least squares (PLS) regression were used from the set of chemometric tools in distinguishing and validating the measured berry fruit extract. ANOVA and PCA showed no significant impact of the origin and freshness of the samples. PLS models were developed to validate the relationship of NIR spectra with TPC and AOA of berry fruits. Representativeness of the models was expressed with the R2and the ratio of performance to deviation. Calculated R2values were above 0.84 and the ratio of performance to deviation was between 1.8 and 3.1, indicating adequacy of the PLS models.
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Jasenka Gajdoš
authors.initials: JG
authors.lastname: Kljusurić
authors.affiliation: University of Food Technologies, Department of Food Preservation and Refrigeration Technology, 26 Maritza Boulevard, BG-4000 Plovdiv, Bulgaria.
authors.forename: Kiril
authors.initials: K
authors.lastname: Mihalev
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bečić
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Polović
authors.affiliation: University of Food Technologies, Department of Food Preservation and Refrigeration Technology, 26 Maritza Boulevard, BG-4000 Plovdiv, Bulgaria.
authors.forename: Mariya
authors.initials: M
authors.lastname: Georgieva
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Senka
authors.initials: S
authors.lastname: Djaković
authors.affiliation: University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia.
authors.forename: Želimir
authors.initials: Ž
authors.lastname: Kurtanjek
keywords: NIR spectroscopy; PLS models; antioxidant activity; berry fruits; total phenolic content