This work aimed to develop the isotope analysis method to quantify the carbon of the C3 photosynthetic cycle in commercial orange nectars, and to measure the legal limit based on Brazilian legislation in order to identify beverages not conforming to the Ministry of Agriculture, Livestock and Food Supply (MAPA). The beverages were produced in a laboratory according to Brazilian law. Adulterated nectars were also produced with a pulpy juice quantity below the level permitted by MAPA. Isotope analyses measured the relative isotope enrichment of the orange nectars and also of their fractions, the purified sugar and the insoluble solids (pulp). From these results the C3 source concentration was estimated using the isotope dilution equation. To determine the existence of adulteration in commercial nectars, a legal limit had to be created according to Brazilian law. Eight commercial nectar brands were analyzed. All were classified as legal. The legal limit was an important methodological innovation that enabled the identification of beverages not conforming to Brazilian law. The methodology developed proved efficient in quantifying the carbon of C3 origin in commercial orange nectars.
Adulteration; Quality; Legal limit; Carbon-13; IRMS; Citrus sinensis
