of the skin and the browning of the cut surface. They have not been shown to 
have much influence on the ripening of apples or to be markedly affected during 
ripening. Chlorogenic acid, which has been identified as one of the main 
phenolics in apples (24), decreases during ripening (29). The function of the 
phenolic compounds and their fate or role during ripening are largely unknown. 
Walker (79) found a steady decrease in concentration of chlorogenic and P- 
coumaryl-quinic acids during early growth and development of apple fruit. Both 
acids reached a near steady level at maturity. 
Nitrogen Compounds 
The primary change occurring in the nitrogen compounds during ripening 
has already been mentioned in the discussion on the climacteric. It is during 
this period that the balance between protein and nonprotein nitrogen is shifted 
toward a predominance in protein (25). There is little evidence of any signi- 
ficant changes in the total nitrogen content in apples after harvest (65). 
Nutritional Value 
Historically, the apple has been known as a fruit whose consumption 
reduces the need for a doctor. Besides having color, appetite, and variety 
appeal, there is considerable evidence that it also possesses definite nutri- 
tional and therapeutic properties (14). The average composition of the apple 
does not reveal any peculiar content that should make it especially beneficial. 
The balance of minerals, vitamins, acids, proteins, and carbohydrates with a 
relatively low total caloric value apparently is such that many people who eat 
apples experience a beneficial health effect, 
Dedolph et al. (11) found that over 400 students who volunteered to eat 
apples every day during the first and second quarters of successive academic 
years at Michigan State University made significantly fewer calls at the Uni- 
versity Health Service Clinic than would be expected on the basis of the entire 
student body. This was especially true for upper respiratory and tension- 
pressure phenomena disorders, 
Slack and Martin (62) observed two groups of 80 to 90 children over a 
2-year period in Liverpool, England, Instructions were given that one group 
should be served apples after each meal and after eating between meals. The 
other group served as a control. No instructions were given concerning oral 
hygiene. After 2 years the gum condition of the children in the apple group 
was significantly better than in the control group. The effect on reducing the 
incidence of dental caries was also encouraging. The authors considered the 
results of this pilot study justified a larger scale study for a longer period 
but pointed out that crisp high quality apples were needed to obtain the bene- 
ficial effects. 
Apples are a relatively good source of ascorbic acid (vitamin C); how- 
ever, varieties differ widely in their content. Grant (17) reports values for 
23 varieties ranging from 0.9 mg. for McIntosh to 12 mg. per 100 g. of cortex 
tissue for Wagener. Kieser and Pollard (40) report a range of 6.9 to 22.5 mg. 
per 100 g. of fresh tissue for 17 varieties of English apples. Hundreds of 
varieties and seedlings have been analyzed and nearly all of the values will 
fall within the wide ranges just cited. Grant (17) also indicates that very 
little loss of ascorbic acid occurs during storage. Others (49, 55) have found 
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