The potential of near infrared spectroscopy for determining the phenolic, antioxidant, color and bactericide characteristics of raw propolis

The phenolic composition (total phenols and flavonoids), antioxidant capacity measured using the Total Equivalent Antioxidant Capacity (TEAC) and the 1,1-dipheny1-2-picrylhydrazyl (DPPH) scavenging % methods, color (L* a*b*) and biocide properties of 53 propolis samples from Chile and Spain (Galicia and Castilla y Leon) were analyzed using methods of reference. Study of the correlations between the parameters examined revealed a significant correlation between the phenolic composition, the antioxidant activity and the color, the yellower and paler the color the lower the phenolic content and the antioxidant capacity. Moreover, there was a significant correlation between the flavonoid content and the bactericide properties. We studied the use of near infrared spectroscopy technology and of a remote reflectance fiber-optic probe, to predict these properties was studied. Calibration statistical descriptors on crushed propolis were excellent for total polyphenols, total flavonoids, the TEAC, the DPPH scavenging %, L*, a*, b*, and bactericide properties similar to beta-lactams and macrolides. The model generated permitted the determination of these variables in unknown samples of propolis. (C) 2017 Elsevier B.V. All rights reserved.