This study examined how the concentrations of volatile organic compounds (VOCs) evolve in apple puree during processing under various temperature and grinding conditions. A full factorial experimental design was applied, combining two temperatures (70 and 95 °C) with two grinding speeds (300 and 1000 rpm). VOCs were identified and quantified by a dynamic headspace analysis coupled with GC-MS, with calibration carried out at four critical stages of the process. Results showed that after cooking, higher grinding speeds led to a significant increase in aldehydes such as (E)-2-hexenal (from 0.06 to 0.13 mg/kg at 70 °C and from 0.016 to 0.054 mg/kg at 95 °C) and hexanal (from 0.53 to 0.70 mg/kg at 70 °C and from 0.14 to 0.30 mg/kg at 95 °C). In contrast, acetaldehyde concentrations decreased. Raising the temperature from 70 to 95 °C significantly reduced the concentrations of most VOCs (p-value <0.001), with the exception of furfural, which began to form at temperatures above 82.5 °C. This overall reduction in VOCs is likely due to chemical or enzymatic transformations rather than volatilization. These findings represent an initial step toward developing a decision-support tool aimed at identifying optimal processing conditions based on VOC changes to enhance quality control in fruit purees.
Dieng et al. (Mon,) studied this question.