EFFECT OF PROCESSING ON VITAMINS 17 



slightly higher in C content than apple sauce. The former investigators, as well 

 as Bracewell, Hoyle, and Zilva (14), obtained nearly complete retention of C in 

 apples baked in their skins. Becker (9) described Vitapric, a very active 

 vitamin C concentrate made from ripened paprika juice. The content of 

 ascorbic acid is 0.45 percent which is unchanged after sterilization. Miller and 

 Robbins (141) found that guavas lost no C when converted into jelly. Un- 

 published work in this laboratory showed no C in apple jelly. 



Von Euler and Klussmann (51) found that ascorbic acid was much more 

 stable in fruits and in acid solutions than in roots and in green plant tissue. 

 Also, Carteni and Morelli (181 demonstrated much greater losses in C at pH 4.93 

 than at pH 9.64. Loss of vitamin C by exposure to air is well illustrated by an 

 experiment reported by Kohman, Eddy, and Gurin (108) who showed that 

 shredded carrots lost much C on relatively short exposures. Experience in this 

 laboratory (55) indicates that fresh cider loses its C rather rapidly by oxidation. 

 Prompt refrigeration is necessary to prevent loss. Pasteurization or benzoate 

 preservation have not been effective in conserving the vitamin C in fresh cider, 

 cranberry, blueberry or vegetable juices. Sah, Ma, and Chang (180) found that 

 boiling lotus juice for as little as 5 minutes destroyed over 40 percent of the vita- 

 min C. Morgan, Langston, and Field (153) showed that sodium benzoate could be 

 used in the preservation of orange juice without injuring its C content. That 

 canned foods lose little vitamin C on storage has been shown by Eddy, Kohman, 

 and Halliday (48,) and by Fellers and Isham (56). The latter found that after 

 canning, tomato juice lost no C in 5 months at room temperature. 



Summary on Vitamin C 



The British Medical Research Council (137) states, "The commercial process 

 of canning vegetables also leads to a considerable degree of destruction of the 

 vitamin C in vegetables like cabbage and runner beans, whereas in tomatoes 

 very little destruction occurs unless there is exposure to air. Actual investiga- 

 tion of products canned commercially has shown that in many cases vitamin C 

 is still present, although a certain amount of loss has usually taken place. This 

 holds for many fruits and vegetables." These recent studies as well as many 

 which have been previously summarized by Kohman (106), Sherman and 

 Smith (193), the British Medical Council (137), and others, show that oxidation 

 is the primary cause of loss of vitamin C in cooked and canned foods. Heat, of 

 course, accelerates oxidation and enzyme activities and is a powerful and not 

 easily controlled element involved in the conservation of C in food manufactur- 

 ing processes. Blackfan (12) summarizes the subject by the statement, 

 ' ' Vitamin C apparently suffers greater destruction in cooking than in canning 

 due to the greater exposure of oxygen in the former process. The losses reported 

 for cooked vegetables are probably unnecessarily large because of the long 

 cooking periods used. Experiments are needed to determine the vitamin C 

 content of vegetables cooked only until they are tender. In cooking and canning, 

 the water soluble substances find their way into the surrounding liquid. 

 Vitamin C is stabilized by acid and therefore suffers less destruction in canning 

 fruits and acid vegetables." Scheunert's (183) conclusions, based on German 

 experiments, agree with those just cited from England and America. 



