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Keywords:

  • orange juice;
  • partition coefficient;
  • pasteurization;
  • pulp;
  • SPME

ABSTRACT:  Release of aroma compounds in orange juice according to pulp content and pasteurization was performed by headspace-solid phase microextraction (HS-SPME), HS-SPME-GC-olfactometry, and by the determination of partition coefficients of aroma compounds between the juice and the headspace. Orange juices with 12% and 6% pulp contents were collected from a processing line before and after pasteurization. HS-SPME revealed that the 6% pulp juice was the most affected by pasteurization, with an increase in the release of several aroma compounds that are generated by heat treatment (that is, α- and β-terpinéol) and a decrease in the release of compounds sensitive to pasteurization (that is, neral and geranial). Principal component analysis of olfactometric data allowed discriminating fresh and pasteurized juices, regardless of the pulp content. The determination of the gas/liquid partition coefficients by the phase ratio variation method was possible for 7 aroma compounds. For the most hydrophobic ones, the release of aroma compounds in fresh juices was higher in the 6% pulp juice than in the 12% pulp juice. However, in pasteurized juices, the difference between their partition coefficients was less marked. Potential interactions between cloud proteins and hydrophobic aroma compounds may explain this phenomenon.