Color Changes of Tomato Purees During Storage at Freezing Temperatures

Abstract

The changes in color of unblanched and blanched tomato purees during storage at -7 and -18 °C were studied. They showed the typical sigmoidal-shape of radical reactions and were well described by the Logistic equation (R > 0.95; P < 10 -3 ). After an initial induction time, a progressive increase in the bleaching rate was found for both unblanched and blanched frozen tomato purees. The color changes for the unblanched sample were statistically higher than those for the heated one. In the former case, the bleaching of carotenoids was attributed to both chemical and enzyme-catalyzed oxidation reactions. The effect of storage temperatures on color changes was appreciable only in the case of the unblanched tomato samples.

Impact of high‐pressure and traditional thermal processing of tomato purée on carotenoids, vitamin C and antioxidant activity

“…It has consistently been shown that changes associated with freezing can cause aggregation and conformational modifications of enzymes molecules, leading to a reduction of enzymatic activity. 33 CIELab parameters (L * , a * and b * ) were significantly higher both in the untreated and in the HP tomato purée compared with the rest of the treatedtomato purées. HP tomato purée showed a significant increase in L * value, which indicated a lightening of purée surface colour.…”

Stability of dehydrofrozen tomatoes pretreated with alternative osmotic solutes

“…Urbanyi and Horti (1989), Biacs and Wissgott (1997), Calligaris, Falcone, and Anese (2002) reported that progressive colour loss, accompanied by a reduction of carotenoid content, might take place in frozen tomato during storage. The same was observed for the osmodehydrofrozen tomato samples.…”

A novel approach for color degradation kinetics of paprika as a function of water activity

“…Color changes of selected vegetables and fruits in growth or under post harvest storage conditions have been reported to be sigmoid in nature, and have been modeled by a logistic function (Calligaris, Falcone, & Anese, 2002;Jacobi, MacRae, & Hetherington, 1998;Tijskens & Evelo, 1994). For color changes during thermal processing and subsequent storage, however, the first order kinetic models better described the color alterations (Ahmed, Kaur, et al, 2002;Gunawan & Barringer, 2000;Ismail & Revathi, 2006;Shin & Bhowmik, 1995;Wagner & Warthesen, 1995).…”