Fruit ascorbic acid content

Giuntini, D., G. Graziani, B. Lercari et al. 2005. Changes in carotenoid and ascorbic acid contents in fruits of different tomato genotypes related to the depletion of UV-B radiation. J. Agric. Food Chem. 53 3174-3181. 

Yahia EM, Contreras M and Gonzalez G. 2001b. Ascorbic acid content in relation to ascorbic acid oxidase activity and polyamine content in tomato and bell pepper fruits during development, maturation and senescence. Lebensm Wiss u-Technol 34 452-457. 

Yahia EM, Soto G, Puga V and Steta M. 2001a. Hot air treatment effect on the postharvest quality and ascorbic acid content in tomato fruit. In Artes F, Gil MI and Conesa MA, editors. Improving Postharvest Technologies of Fruits, Vegetables and Ornamentals, Volume 2. Paris International Institute of Refrigeration, pp. 550-556. 

Ascorbic acid is probably the most labile bioactive compound in fruit juices and fruit and vegetable pieces, as we described in the first part of this chapter. Retention of this phytochemical after the nonthermal treatments ranged from 47% to 100%, depending on the intensity of the applied treatment and the product. For example, the greatest losses of vitamin C were found in fresh-cut red lettuce and melon treated with IR and HHP (Fan and others 2008 Wolbang and others 2008), respectively. However, the use of gamma radiation in various vegetables retained 100% of their total ascorbic acid content (Fan and others 2008). 

Ascorbic acid level in grapes is relatively low compared with other fruits. Zubeckis (5) in Canada reported that ascorbic acid in fresh grapes varied from 1.1 to 11.7 mg/100 ml juice, except for the variety Veeport. This Canadian variety contained a high content of ascorbic acid (33.8 mg/100 ml juice). More recently, Oumac (188) determined the ascorbic acid content of seven grape juices and found a range from 2.0 to 6.0 mg/100 ml. 

Table VII. Ascorbic Acid Content of Several Fruits Grown in Ohio...

Atkins et al. (14) reported that most of the ascorbic acid that occurs in the orange is present as a constituent of the peel. Based on the weight of whole fruit, the juice contains about 25% of the total ascorbic acid content. The juice of the grapefruit contains only about 17% of the total ascorbic acid content on the same basis. 

A number of workers examined the effect of light exposure on ascorbic acid content and the general conclusion is that direct sunlight has a positive effect on its content i.e., exposure to direct sunlight tends to increase the ascorbic acid content of fruit. 

Long et al. (20) found that the ascorbic acid content of grapefruit was inversely related to their size. In Valencia oranges, Sites and Reitz (21) found a positive correlation between ascorbic acid and the soluble solids of fruit from the same tree. 

As might well be expected, other citrus fruits exhibit the same type of seasonal decline in ascorbic acid content of the juice with maturity. Harding and Sunday (22) reported that the ascorbic acid content of tangerines may be 35mg/100ml of juice in the early season and as low as 10-15mg per 100ml if the fruit is allowed to overmature. 

Itoo, S., Aiba, M., and Ishihata, K. Comparison of ascorbic acid content in acerola fruit from different production regions depend on degree of maturity, and its stability by processing. Nippon Shokuhin Kogyo Gakkaishi, 37, 726-729, 1990. 

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. 

Genetic Variation. The concentration of many individual nutrients in foods of plant origin is under genetic control. Baker (34) reviewed some examples of genetic manipulation that improved the quantity of )3-carotene in tomatoes, methionine in beans, and lysine in com. Variations of ascorbic acid content of different varieties of raw vegetables and fruits is notoriously high (35). Twofold variation in vitamin C concentration in different strains of a vegetable or a fmit is common and a fivefold variation can be found. Differences in ascorbic acid contents (35- to 300-fold) of different strains of a fmit were reported prior to 1950 (36). These reports have not been substantiated. 

Betancourt et al. (46) found that in two varieties of tomatoes, plant-ripened fruit accumulated more (22%) RAA than did fruit ripened off the plant. Unfortunately, these researchers did not measure the total ascorbic acid content of tomatoes in their study. Pantos and Markakis (47) found that two cultivars of tomatoes contained 25-33% more total vitamin C when they were ripened on the vine rather than artificially. Conversely, Matthews et al. (48) reported that RAA of Walter tomatoes harvested at the green-mature stage and ripened off the plant was essentially the same as in those ripened on the plant. Thus, there may be varietal differences in this regard. 

Ascorbic acid content determined in kiwi fruit samples by means of HPLC with UV detection and voltammetric titration. 

Continued depletion of L-ascorbic acid in stored fruit-juices may be partly due to interaction with the hydrogen peroxide initially produced by aerobic mechanisms. Indeed, introduction of hydrogen peroxide, in amounts equivalent to the L-ascorbic acid content, into three-month old, blackcurrant-juice samples, caused a 50% loss of L-ascorbic acid in one hour, probably ascribable to formation of dehydro-L-ascorbic acid. 

Okafor P.N., Nwogbo E., (2005), Determination of nitrate, nitrite, N-nitrosamines cyanide and ascorbic acid contents of fruit juices maijeted in Nigeria, African Journal of Biotechnology, 4(10), 1105-1108. 

Kabasakalis, V., Siopidou, D., and Moshatou, E. 2000. Ascorbic acid content of commercial fruit juices and its rate loss upon storage. Food Chem. 70, 325-328. 

Polyamides, Polyesters and other polymers. Polypropylene is p>art of the Polyolefin group and used largely in MAP, in both forms continuous and perforated. Sanz et al. (1999) studied the quality of strawberries packaged with polypropylene film, with proper perforations, during commercial postharvest practices. They concluded that perforated-mediated MA packaging helped to preserve fruit ripeness degree better, maintaining its nutritional value, measured as ascorbic acid content. 

Valente, A. and Albuquerque, T. 2011. Ascorbic acid content in exotic fruits A contribution to produce quabty data for food composition databases. Food Res. Int. 44 2237-2242. 

Furthermore, the same authors also showed that at any concentration used in their experiments, the driving force reduction due to the concentration polarisation effect was higher than that of the temperature polarisation effect. For example, at 8 mol/kg, CaCl2 corresponds to 225 Pa of reduction in driving force due to concentration polarisation, whereas the reduction due to temperature polarisation effect is only 75 Pa. The best result obtained by Ravindra Babu et al. (2008) in terms of pineapple juice concentration was up to 62° Brix, preserving the ascorbic acid content of the fruit. 

The relation of total sulfur dioxide content and other factors to color changes during storage of apricots is discussed by Nichols and Reed (1931), Nichols ei al. (1938), Chace et al. (1930, 1933), and Sorber (1944). The role of sulfuring in dehydration of cherries and small fruits is discussed by Wiegand et al. (1945), and the effects of methods of sulfuring, dehydration, and temperature of storage on ascorbic acid content and carotene content of dehydrated peaches by Eheart and Sholes (1946), as well as others mentioned previously. 

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