Tracking thermal degradation on passion fruit juice through Nuclear Magnetic Resonance and chemometrics

- This approach allowed to identify the changes in the juice composition.
- Thermal process induces changes at low temperatures, and formation of HMF at higher.
- NMR/chemometrics is useful to follow temperature/time effects on juice process.

Thermal food processing mainly aims to control microorganism in order to extend its shelf life. However, it may induce chemical and nutritional changes in foodstuff. The Nuclear Magnetic Resonance (NMR) coupled to multivariate analysis was used to evaluate the effect of different thermal processing conditions (85 and 140 °C for 4; 15; 30; and 60 s) on the passion fruit juice using an Armfield pasteurizer. Through this approach it was possible to identify the changes in the juice composition. The temperature and the time lead to a hydrolysis of the sucrose to glucose and fructose. Additionally, juice submitted to 140 °C for 60 s results in the degradation of the sucrose and the formation of 5-(hydroxymethyl)-2-furfural (HMF). Despite no novel chemical marker has been identified, the 1H NMR chemometrics approach may contribute in the choice of the temperature and time to be employed in the juice processing.