A rapid method to monitor quality of apple juice during thermal processing

E. Cohen, Y. Birk, C. H. Mannheim, I. S. Saguy

Research output: Contribution to journalArticlepeer-review

77 Scopus citations


Quality deterioration of apple juice, thermally processed at constant temperatures ranging from 95 to 123 °C for 2 to 30 min, was measured by three quality indexes: nonenzymatic browning (NEBI), 5-hydroxymethylfurfural (HMF) and fluorescence relative index (FLRI). All three indexes followed an apparent zero-order reaction with activation energies of 148.6, 151.1 and 148.6 kJ/mole for NEBI, HMF and FLRI, respectively. FLRI correlated highly with HMF (R2 = 0.98). The correlation between HMF and FLRI, obtained under constant temperatures, was verified under continuous process conditions of 85 to 135 °C and 30 to 180 s. FLRI was found to be a quantitative criterion, which could be applied for 'on-line' monitoring of the deleterious effects of thermal processing of apple juice.

Original languageEnglish
Pages (from-to)612-616
Number of pages5
Issue number7-8
StatePublished - 1 Jan 1998


  • Browning
  • Fluorescence
  • HMF
  • Kinetics

ASJC Scopus subject areas

  • Food Science


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