doi: 10.17113/ftb.54.02.16.4095
Near-Infrared Spectroscopic Analysis of Total Phenolic Content and Antioxidant Activity of Berry Fruits
Jasenka Gajdoš Kljusurić1*, Kiril Mihalev2, Ivana Bečić1, Ivana Polović1, Mariya Georgieva2, Senka Djaković1 and Želimir Kurtanjek1
1University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb, Croatia
2University of Food Technologies, Department of Food Preservation and Refrigeration Technology, 26 Maritza Boulevard, BG-4000 Plovdiv, Bulgaria
Article history:
Received January 30, 2015
Accepted December 23, 2015
Key words:
berry fruits, antioxidant activity, NIR spectroscopy, PLS models, total phenolic content
Summary:
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 R2 and the ratio of performance to deviation. Calculated R2 values were above 0.84 and the ratio of performance to deviation was between 1.8 and 3.1, indicating adequacy of the PLS models.
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