Effects of pulsed electric fields and cinnamon essential oils on the quality of apple juice

ABSTRACTEFFECTS OF PULSED ELECTRIC FIELDS AND CINNAMONESSENTIAL OILS ON THE QUALITY OF APPLE JUICEKaraoğuz Turgut, BengiMSc., Department of Food EngineeringSupervisor: Assoc. Prof. Gülsün Akdemir EvrendilekJuly 2011, 107 pagesThe influence of pulsed electric fields (PEF) on some physical properties of apple juice with or without addition of cinnamon essential oil (ceo) was investigated in this study. Apple juice samples were treated by PEF alone, 0.0005 ? L/mL ceo+PEF, 0.003 ? L/mL ceo+PEF and 0.06 ? L/mL ceo+PEF. PEF treatment parameters were 3 µs pulse duration, 500 pps frequency, 30 kV/cm electric field strength and 0 (control), 101, 202, 302, 403, 504, and 604 µs treatment time. Results revealed that regardless of the concentration of added ceo and PEF processing conditions no significant difference was detected among the control, PEF-treated and ceo+PEF treated samples for pH, titratable acidity (%TA), ? Brix, total phenolic substances, total antioxidant capacity and FT-IR spectra (p>0.05). The same process parameters caused significant reduction on inoculated Escherichia coli O157:H7 and Listeria monocytogenes cultures (p?0.05). Moreover, increased ceo concentration, when treatment time was constant, caused more inactivation of both cultures (p?0.05). It was concluded that ceo+PEF application depending on ceo concentration can successfully used to process apple juice samples without adversely affecting some important quality parameters and with inactivation of pathogenic microorganisms. Addition of natural plant essential oils such as cinnamon essential oil to apple juice samples, which provides new food product development and carries antimicrobial activity, and following PEF processing which has synergistic effect on microbial inactivation is promising approach in food industry.Key words: Pulsed electric field (PEF), cinnamon essential oil, apple juice, microbial inactivation.