Carbon isotope analysis in apple nectar beverages

Abstract

The aims of this study were to use the isotope analysis method to quantify the carbon of C3 photosynthetic cycle in commercial apple nectars and to determine the legal limit to identify the beverages that do not conform to the safety standards established by the Brazilian Ministry of Agriculture, Livestock and Food Supply. These beverages (apple nectars) were produced in the laboratory according to the Brazilian legislation. Adulterated nectars were also produced with an amount of pulp juice below the permitted threshold limit value. The δ13C values of the apple nectars and their fractions (pulp and purified sugar) were measured to quantify the C3 source percentage. In order to demonstrate the existence of adulteration, the values found were compared to the limit values established by the Brazilian Law. All commercial apple nectars analyzed were within the legal limits, which enabled to identify the nectars that were in conformity with the Brazilian Law. The isotopic methodology developed proved efficient to quantify the carbon of C3 origin in commercial apple nectars.

Use of stable isotopes of carbon to detect coconut water adulteration

“…Other authors have published isotope values of cane sugar (refined and crystal). Banerjee et al (2015) and Figueira et al (2013) found values from -12.50 ‰ to -11.90 ‰ and -13.06 ‰ to -12.51 ‰, respectively, and Jahren et al (2006), from -12.71 ‰ to -11.59 ‰. Due to its influence on results, this high variation (3 ‰) must be considered in the calculation of results.…”

“…The percentage of theoretical C 3 carbon was calculated based on beverages soluble solids content, by equations 2 and 3 (Figueira, 2013).…”

Comparison between isotope ratio mass spectrometry (IRMS) and cavity ring‐down spectroscopy (CRDS) for analysing the carbon isotope ratio and detection of adulteration in coconut water

“…Although there were no significant differences between CM‐CRDS and EA‐IRMS for the δ 13 C values in fructose and sucrose, a higher variation was found using the CM‐CRDS method. EA‐IRMS analysis revealed mean δ 13 C values of −13.16‰ for sucrose (from EA‐IRMS), which fell into the same range of other studies (between −14.20‰ and −11.59‰) (Jahren et al ., 2006; Fig ueira et al ., 2013; Banerjee et al ., 2015; Imaizumi et al ., 2019). Glucose and fructose had approximately 1‰ lower δ 13 C than sucrose.…”