Nutritive Value of Canned Foods.

Abstract

ITRUS juices have long C been regarded as excellent sources of vitamin C (ascorbic acid) and have been shown to contribute significant amounts of the vitamin to the average American diet.From the standpoint of convenience and economy the canning of citrus juices has made available to the general public a n excellent source of this vitamin. The retention of ascorbic acid during canning operations and subsequent storage becomes of paramount importance in evaluating the nutritional value of canned citrus iuices.The obserbed reLention of ascorbic acid during canning operations varied from 91.6 to 107.5% at three California and four 4rizona grapefruit juice canneries, and from 9i.k to 101.6% at fi\e California orange juice canneries. The aierage retention was 98y0 for both products. During storage at 70" F. for 18 months grapefruit juice lost ascorbic acid at a constant rate of about 1% a month. Orange juice appeared to lose ascorbic acid more rapidlr during the first few months of storage and less rapidly during the following months, but the aterage monthly rate of loss at the end of 12 months was approxiniatelj 1%. DeFiations from the aierage rate were small, and iariations in canning procedure seemed to hate little effect on this rate. Tests for iron, reductones, and dehrdroascorbic acid in stored samples indicated that these substances were either absent or present in insufficient amounta to interfere with the determination of ascorbic acid.Noore, Wiederhold, Atkins, and hIacDowel1 ( I f ) htudied the retention of ascorbic acid in canned grapefruit juice at twelve Florida canneries and found a n average over-all retention of 97y0,. Wagner, Ives, Strong, and Elvehjein (21) conducted similar studies at trvelve Texas grapefruit juice canneries and found an average over-all retention of 96.595. Ross (16) invcstigatecl tlic; effect of time and temperature on vitamin C retention in canned citrus juices, and several other investigators coiiductcd holding experiments for various times and temperatures (4, 10, 13, 21).Other factors affecting the retention of ascorbic acid in citrus juices are discussed by Riester, Braun, and Pearce ( I S ) , and by Wiederhold, At,kins, and Moore (22).

Effects of storage temperature and duration on total vitamin C content of canned single-strength grapefruit juice

“…At this temperature SSGJ retains more AA than is retained in SSOJ under similar conditions. Higher percent retentions of AA in SSGJ than in SSOJ at high storage temperatures and different storage periods have been reported (Lamb, 1946). As expected, the rate of AA degradation in SSGJ increased with temperature.…”

“…Loss of AA in single-strength grapefruit juice (SSGJ) has been shown to be related to storage time and temperature (Moore et al, 1944;Riester et al, 1945;Lamb, 1946;Moschette et al, 1947;Sheft et al, 1949;Moore, 1949;Freed et al, 1949;Heikal et al, 1967). In those studies, however, TAVC was not determined and most of those studies did not cover a wide range of storage temperatures.…”

EFFECT OF STORAGE ON VITAMINS AND QUALITY IN CANNED FOODS1

“…ascorbic acid retention was decidedly better. According to Lamb (1946), storage a t 2l0C.(70"F.) results in approximately a one per cent per month decrease in the ascorbic acid in citrus juices.…”

“…Prolonged Xtorage: Although some decline of ascorbic acid may be associated with long storage of canned foods, Guerrant et al (1945), Lamb (1946), Olliver (1936, and Riester et ul. 1945), the extent of the decline after the first few weeks appears to be associated with the type of the product and the storage temperature.…”

Concentration and stability of ascorbic acid in marketed reconstituted orange juice

“…The susceptibility of vitamin C (ascorbic acid) to oxidation in aqueous solution and the dependence of the reaction on the presence of dissolved and headspace oxygen has been recognized (Bauernfeind, 1953). Lamb (1946) claimed an 8% drop in 6.5 months in the ascorbic acid content of canned orange juice. A study by Kefford et al (1959) revealed the oxidative destruction of ascorbic acid in canned pasteurized orange juice occurred only during the first few days until the free oxygen disappeared.…”