2.3.5. Hydroxymethylfurfural
The HMF content was determined according to Rada-Mendoza,
Olano, and Villamiel (2002). Samples were placed in a flask of
25 mL; 2 mL each of Carrez I and II reagents were added and the
volume adjusted with ultrapure water. After decantation for
30 min, the supernatant was filtered (0.45 lm) and then injected
(50 lL) into the chromatograph (Nova-Pak C18 column at room
temperature). The mobile phase consisted of methanol: water,
using a linear gradient from 5:95 to 80:20 in 6 min. Isocratic elution
was then continued for 6 min and, finally, initial conditions
were re-established in 1 min and held for 10 min. The flow rate
was 1 mL/min. The UV detector was set at 283 nm. The quantification
was made using HMF standard and the results were expressed
as mg/100 g of jam.