Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy

Abstract

The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption.

Honeybees and their products as bioindicators for heavy metal pollution in Malta

“…Metals that have moderately accumulated in propolis include Zn, Pb and Ag (3.08-51.97, 0.00-28.50 and 4.77-6.49 µg g -1 , respectively). The level of Zn in the current study concurs with that in propolis from Brazil (20±0.01 µg g -1 , Finger et al, 2014) but is lower than that in propolis from Chile and Spain (62.6 µg g -1 , González-Martín et al, 2015).…”

“…Several studies determine the presence of minerals and toxic metals in propolis (González-Martín et al, 2015;Ferreira et al, 2019). Studies have shown that propolis is a good indicator for both bee and plant metal accumulation.…”

Characterization of phenolic profile alterations in metal-polluted bee pollen via capillary electrophoresis

“…Several apiculture products, such as honey, pollen, and propolis, are suitable materials for monitoring environmental contamination (Formicki et al, 2013;González-Martín et al, 2015). This attribute is due to the direct contact that honeybees have with environmental contaminants during flight and through food sources (e.g., plant pollen, nectar, and water) Przybyl ̶ owski and Wilczyńska, 2001).…”

Rapid prediction of Apparent Amylose, total starch, and crude protein by near‐infrared reflectance spectroscopy for foxtail millet (Setaria italica)

“…Near‐infrared reflectance spectroscopy (NIRS) has the advantages of speed, simplicity, efficiency, time‐saving, and environmental friendliness, which can be a good choice (González‐Martín et al, 2015; Lim et al, 2018). Its principle is that the overtones and combination bands of radicals, such as O‐H, C‐H, and N‐H, are absorbed at specific near‐infrared wavelengths.…”