73D-11 |
Shelf life study of bottled tomato ketchup as a function of packaging and storage conditions |
P. S. TAOUKIS1, A. Bournakis, and M. C. Giannakourou. (1) Department of Chemical Engineering, National Technical University of Athens, Iroon Polytechniou 5, 15780, Athens, Greece Color deterioration quantitatively correlates to quality of shelf stable tomato products such as ketchup. Carotenes and xanthophyls contained in tomato, especially lycopene slowly oxidize during the long ambient storage, gradually changing color from bright red to dark brown. Higher oxygen availability and high temperature storage accelerates the change. Switching from glass to polymer packaging for cost reduction and functionality e.g. squeezability, has to be evaluated with regards to its effect to shelf life. The objective of this work was to estimate the effect of temperature and package oxygen permeability on the shelf life of a commercial ketchup product. Three packaging materials, PET, PE-EVOH and glass were studied. Oxygen permeability of PET and PE-EVOH, was measured using the MOCON OXTRAN 2/20. Color of ketchup in the three packages, at 15, 30 and 40° C, was measured for several months. Chromaticity change, DE, of CIELab scale, was modeled with time. Permeability of the PET and EVOH material were 1,85, 3,28 and 4,66 cc-19 mil / 100 in2 / day-atm and 1,9.10-3, 8,4.10-3 and 20,4. 10-3 cc-28 mil / 100 in2 / day-atm at 15, 30 and 40° C respectively. DE of ketchup changed linearly with time with increasing rate from glass to PET and from 15 to 40° C. The rate at 30° C was the same for glass and EVOH but three times faster for PET. The Arrhenius temperature dependence of the color change rate, showed the same activation energy, Ea, for glass and PET (10 kcal/mol) and a higher Ea for EVOH (14.6 kcal/mol). The results suggest that PE-EVOH can replace glass for ketchup packaging when temperatures are kept up to 30° C. Shelf life was determined as 260 and 225 days in glass and PE-EVOH at 30° C, but reduced to 150 and 100 days respectively at 40° C.
Session 73D, Food Packaging
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