THE ANTIOXIDANT ACTIVITY OF TOMATO. IV. EFFECTS OF STORAGE ON OXIDATIVE AND HEAT DAMAGE

Three commercial tomato products (tomato pulp, tomato puree, and tomato paste) were subjected to accelerated aging tests (3 months at 40°C) to evaluate the kinetics of variation of heat damage indexes (5-hydroxymethyl-2-furfural [HMF] and color [ΔE]) and oxidative damage indexes (lycopene, -carotene, ascorbic acid, total phenolics, antioxidant activity of hydrophilic and lipophilic fractions). Experimental data were processed to obtain rate constant values.
HMF formation followed zero-order kinetics in tomato puree, and paste, and first-order kinetics in tomato pulp, to a final value of nearly 160, 200, and 495 mg/kg dw in tomato pulp, puree, and paste.
Significant colour changes were only observed in tomato concentrate.
Ascorbic acid decreased in all products according to pseudo-first-order kinetics, with a higher rate in tomato paste and puree.
A slight increase in total phenolics was observed in all products during storage.
Lycopene concentration was very stable in all products, whereas -carotene decreased at the same rate in all products, to a final 30–40% reduction.
The antioxidant activity of the hydrophilic fraction decreased, to a final reduction of 35–40% in all samples.
The antioxidant activity of the lipophilic fraction also decreased, although to a smaller extent, to a final reduction of about 30% in the three products.
Reduction of antioxidant activity can be ascribed to the loss in ascorbic acid and -carotene.

VII International Symposium on the Processing Tomato

G. Giovanelli, V. Lavelli, C. Peri, E. Pagliarini, B. Zanoni, P. Petrone

5-hydroxymethyl-2-furfural, color, ascorbic acid, lycopene, β-carotene, polyphenols, antioxidant activity

https://doi.org/10.17660/ActaHortic.2001.542.28