Wednesday, April 30, 2014

Thermal Processing Enhances the Nutritional Value of Tomatoes by Increasing Total Antioxidant Activity

So the lycopene content I'm getting from tomatoes should be in a cooked format. I've been trying to eat two medium tomatoes at every dinner. This is why I'm going for tomatoes. But don't listen to me, I know nuthin, that's what your doctor is for.
Tomatoes Linked to Lower Stroke Risk

Heating them here:
http://pubs.acs.org/doi/abs/10.1021/jf0115589?
Department of Food Science and Institute of Comparative and Environmental Toxicology, Stocking Hall, Cornell University, Ithaca, New York 14853
J. Agric. Food Chem., 2002, 50 (10), pp 3010–3014
DOI: 10.1021/jf0115589
Publication Date (Web): April 17, 2002
Copyright © 2002 American Chemical Society

Abstract

Processed fruits and vegetables have been long considered to have lower nutritional value than their fresh commodities due to the loss of vitamin C during processing. This research group found vitamin C in apples contributed <0.4% of total antioxidant activity, indicating most of the activity comes from the natural combination of phytochemicals. This suggests that processed fruits and vegetables may retain their antioxidant activity despite the loss of vitamin C. Here it is shown that thermal processing elevated total antioxidant activity and bioaccessible lycopene content in tomatoes and produced no significant changes in the total phenolics and total flavonoids content, although loss of vitamin C was observed. The raw tomato had 0.76 ± 0.03 μmol of vitamin C/g of tomato. After 2, 15, and 30 min of heating at 88 °C, the vitamin C content significantly dropped to 0.68 ± 0.02, 0.64 ± 0.01, and 0.54 ± 0.02 μmol of vitamin C/g of tomato, respectively (p < 0.01). The raw tomato had 2.01 ± 0.04 mg of trans-lycopene/g of tomato. After 2, 15, and 30 min of heating at 88 °C, the trans-lycopene content had increased to 3.11± 0.04, 5.45 ± 0.02, and 5.32 ± 0.05 mg of trans-lycopene/g of tomato (p < 0.01). The antioxidant activity of raw tomatoes was 4.13 ± 0.36 μmol of vitamin C equiv/g of tomato. With heat treatment at 88 °C for 2, 15, and 30 min, the total antioxidant activity significantly increased to 5.29 ± 0.26, 5.53 ± 0.24, and 6.70 ± 0.25 μmol of vitamin C equiv/g of tomato, respectively (p < 0.01). There were no significant changes in either total phenolics or total flavonoids. These findings indicate thermal processing enhanced the nutritional value of tomatoes by increasing the bioaccessible lycopene content and total antioxidant activity and are against the notion that processed fruits and vegetables have lower nutritional value than fresh produce. This information may have a significant impact on consumers' food selection by increasing their consumption of fruits and vegetables to reduce the risks of chronic diseases.

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