Content of Fruits and Vegetables

Carrots, tomatoes, and dark green vegetables are rich in specific carotenoids. Numerous epidemiological studies have shown that the increased intake of fruits and vegetables is associated with a reduced risk of lung and other epithelial cancers. Accurate food composition data have been prepared to test the association between dietary intake of specific carotenoids and disease incidence (Table 63.1). 

FIGURE 63.1 Starting with mevalonate, carotenoids are biosynthesized by a special branch of the terpenoid pathway. The first C-40 hydrocarbon unit formed is phytoene, a carotenoid with three conjugated double bonds, which then is enzymatically desaturated to successively yield (3-carotene, neurosporene, and lycopene. Other carotenoids such as (3-carotene and oxocarotenoids are produced from lycopene following cyclization and hydroxylation reactions. Thus, lycopene is a central molecule in the biosynthesis pathway of carotenoids. 

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Paganga, G. et al.. The polyphenolic content of fruit and vegetables and their antioxidant activities what does a serving constitute Free Radical Res., 30, 153, 1999. Maatta, K.R. et al.. High-performance liquid chromatography (HPLC) analysis of phenolic compounds in berries with diode array and electrospray ionization mass spectrometric (MS) detection Rihes species, J. Agric. Food Chem., 51, 6736, 2003. 

Paganga G, Miller N and Rice-Evans CA. 1999. The polyphenolic content of fruit and vegetables and their antioxidant activities. What does a serving constitute Free Radic Res 30(2) 153-162. 

Laboratory studies of vitamin and mineral inadequacy associate such deficiencies with DNA damage, which indicates that the vitamin and mineral content of fruits and vegetables may explain the observed association between fruit and vegetable intake and cancer risk. Antioxidants such as vitamin C (whose dietary source is fruits and vegetables), vitamin E, and selenium... 

The expression of results in analytical chemistry is mostly in SI units (all base units except the candela and many derived units). The principles to be followed to achieve the comparability and traceability of measurements to the SI have been clearly stated [1,2]. However, certain types of measurements are expressed in conventional units. Turbidity evaluation in water quality analysis, determination of soluble content of fruit and vegetable products by the refractometric method, measurement of caking power of hard coal by the Roga test, determination of the octane number of fuel and seric protein analysis are some examples. 

The ascorbic acid content of fruits and vegetables is markedly affected by variety, and to a lesser degree by maturity and climate. Increased exposure to sunlight and ripening on the plant generally enhances the vitamin C content of the edible portion. Ascorbic acid concentration within a fruit or vegetable often varies largely from part to part. 

Mangels AR, Holden JM, Beecher GR et al. Carotenoid content of fruits and vegetables. An evaluation of analytical data. J Am Diet Assoc 1993 93 284-9. 

J. Koziet, A. RoBmann, G.J. Martin, P. Johnson (1995) Determination of the oxygen-18 and deuterium content of fruit and vegetable juice water. An european inter-laboratory comparison study. Anal. Chim. Acta 302. 29-37... 

B. J. Kaplan, et al., Effective Mood Stabilization with a Chelated Mineral Supplement An Open-Label Trial in Bipolar Disorder. Journal of Clinical Psychiatry 62 (2001) 936-944 A. B. Mayer, Historical Changes in the Mineral Content of Fruits and Vegetables. British Food Journal. 99 (1997) 207-211 C. W. Popper, Do Vitamins or Minerals (Apart from Lithium) Have Mood-Stabilizing Effects Journal of Clinical Psychiatry 62, no. 12 (2001) 933-944 S. J. Schoenthaler and I. D. Bier, The Effect of Vitamin-Mineral Supplementation on Juvenile Delinquency Among American Schoolchildren A Randomized, Double-Blind Placebo-Controlled Trial. Journal of Alternative and Complementary Medicine 6 (February 2000) 7-17. 

In addition, another point should be considered. What is the real availability of phenolics to be absorbed in the intestinal tract The above mentioned epidemiological studies on the flavonoid content of fruit and vegetables, were performed on lyophilised material extracted by boiling with HCl in methanol-water (50%) [68]. These conditions are harsher than those actually occurring after the ingestion of food, when digestive enzymes will play a much more important role. Thus, the availability (in vivo extraction from food) of phenolics in the gastro-intestinal tract, may be very different from the numbers reported [68]. 

The real availability of fruit and vegetable phenolics ready to be absorbed in the intestinal tract should also be studied. Analysis of the flavonoid and phenolic content of fruit and vegetables does not provide a real picture of the compounds which may be released from plant tissues after ingestion and which may be available for absorption. Studies concerning the real availability of food phenolics should be carried out. 

The O. a. content of fruits and vegetables is usually less than 10 mg/100 g fresh weight however, rhubarb leaves contain 700 mg, rhubarb stems 300 mg, celery stems up to 600 mg, and spinach 60-200 mg/100 g fresh weight. 

Sass-Kiss A, Kiss J, Milotay P, Kerek MM, Toth-Markus M. Differences in anthocyanin and carotenoid content of fruits and vegetables. FoodRes. Intern. 38, 1023-1029, 2005. 

Table 4 Total Phenolic Content of Fruits and Vegetables ...

PHENOLIC CONTENT AND COMPOSITION, AND VITAMIN C CONTENT OF FRUITS AND VEGETABLES... 

Schossler, K., Salimi, J., Knorr, D 2011. The application of ultrasound in drying processes Effect of water content of fruit and vegetable tissue. Proceedings of 5th Nordic Drying Conference, Helsinki. 

Up to 50% of the pantothenic content of fruits and vegetables is lost in canning or freezing, and storage, of fruits and vegetables. 

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