Effect of postharvest storage and processing on the antioxidant constituents (flavonoids and vitamin C) of fresh-cut spinach.

The effect of modified atmosphere packaging (MAP) and cooking on the flavonoids and vitamin C content (ascorbic + dehydroascorbic acid; AA + DHAA) of fresh-cut spinach was evaluated. The total flavonoid content (approximately 1000 mg kg(-)(1) f.w.) remained quite constant during storage in both air and MAP atmospheres, while vitamin C (750 mg kg(-)(1)f.w.) was better preserved in MAP-stored spinach. AA was transformed to DHAA during storage, and its concentration was higher in MAP-stored tissues. The free-radical scavenging activity of the isolated flavonoids was tested, and only those flavonoids with either a dihydroxyl grouping or acylated with ferulic acid showed significant activity. A decrease in the total antioxidant activity was observed during storage, particularly important in MAP-stored spinach. The higher content of DHAA and lower content of both AA and antioxidant flavonoids in the MAP-stored samples could explain this antioxidant activity decrease. Boiling extracted 50% of total flavonoids and 60% vitamin C in the cooking water. However, flavonoid glucuronides were extracted more in the cooking water than the other glycosides. The vitamin C content of the cooked tissue was higher in those samples stored in MAP.

[1]  F. Tomás-Barberán,et al.  Effect of modified atmosphere packaging on the flavonoids and vitamin C content of minimally processed Swiss Chard (Beta vulgaris subspecies cycla) , 1998 .

[2]  J. Vinson,et al.  Phenol Antioxidant Index: Comparative Antioxidant Effectiveness of Red and White Wines , 1995 .

[3]  A. Meyer,et al.  Fruit Hydroxycinnamic Acids Inhibit Human Low-Density Lipoprotein Oxidation in Vitro , 1998 .

[4]  G. Williamson,et al.  Dietary quercetin glycosides: antioxidant activity and induction of the anticarcinogenic phase II marker enzyme quinone reductase in Hepalclc7 cells. , 1996, Carcinogenesis.

[5]  B. P. Klein,et al.  Harvesting, processing, and cooking influences on vitamin C in foods [Ascorbic acid] , 1982 .

[6]  M. Aritomi,et al.  Flavonol glycosides in leaves of Spinacia oleracea , 1985 .

[7]  F. Tomás-Barberán,et al.  Anthocyanins and flavonoids from shredded red onion and changes during storage in perforated films , 1996 .

[8]  F. Tomás-Barberán,et al.  Acylated flavonol glycosides from spinach leaves (Spinacia oleracea) , 1997 .

[9]  J. Dufour,et al.  Ascorbic, Dehydroascorbic and Isoascorbic Acid Simultaneous Determinations by Reverse Phase Ion Interaction HPLC , 1992 .

[10]  A. I. Nelson,et al.  Effects of Modified Storage Atmospheres on Ascorbic Acid and Other Quality Characteristics of Spinach , 1966 .

[11]  E. Frankel,et al.  Natural antioxidants in grapes and wines , 1994 .

[12]  C. Berset,et al.  Use of a Free Radical Method to Evaluate Antioxidant Activity , 1995 .

[13]  B. Ames,et al.  Oxidants, antioxidants, and the degenerative diseases of aging. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[14]  C. Rice-Evans,et al.  Polyphenolic flavanols as scavengers of aqueous phase radicals and as chain-breaking antioxidants. , 1995, Archives of biochemistry and biophysics.

[15]  M. Aritomi,et al.  Three highly oxygenated flavone glucuronides in leaves of Spinacia oleracea , 1984 .