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 < 04% 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 076 +/- 003 micromol of vitamin C/g of tomato After 2, 15, and 30 min of heating at 88 degrees C, the vitamin C content significantly dropped to 068 +/- 002, 064 +/- 001, and 054 +/- 002 micromol of vitamin C/g of tomato, respectively (p < 001) The raw tomato had 201 +/- 004 mg of trans-lycopene/g of tomato After 2, 15, and 30 min of heating at 88 degrees C, the trans-lycopene content had increased to 311+/- 004, 545 +/- 002, and 532 +/- 005 mg of trans-lycopene/g of tomato (p < 001) The antioxidant activity of raw tomatoes was 413 +/- 036 micromol of vitamin C equiv/g of tomato With heat treatment at 88 degrees C for 2, 15, and 30 min, the total antioxidant activity significantly increased to 529 +/- 026, 553 +/- 024, and 670 +/- 025 micromol of vitamin C equiv/g of tomato, respectively (p < 001) 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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Thermal Processing Enhances the Nutritional Value of Tomatoes by Increasing Total Antioxidant Activity

Natural antioxidants from residual sources.

Consumption of fruits and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten and are large contributors of phenolic compounds in European and North American diets. The peels of apples, in particular, are high in phenolics. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production in New York state were investigated. The values of the peels were compared to those of the flesh and flesh + peel components of the apples. Within each variety, the total phenolic and flavonoid contents were highest in the peels, followed by the flesh + peel and the flesh....

Antioxidant activity of apple peels

Epidemiological studies have shown that consumption of whole grains and grain-based products is associated with reduced risk of chronic diseases. The health benefits of whole grains are attributed in part to their unique phytochemical composition. However, the phytochemical contents in grains have been commonly underestimated in the literature, because bound phytochemicals were not included. This study was designed to investigate the complete phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their antioxidant activities in uncooked whole grains. Corn had the highest total phenolic content (15.55 ± 0.60 μmol of gallic acid equiv/g of grain) of the grains tested, followed by wheat (7.99 ± 0.39 μmol of gallic acid equiv/g of grain), oats (6.53 ± 0.19 μmol of gallic acid equiv/g of grain), and rice (5.56 ± 0.17 μmol of gallic acid equiv/g of grain). The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats and wheat, and 62% in rice), ...

Wu Jianming

Papers

The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals