Norris (58) described the development and application of new light 
transmittance instruments to measure internal pigment characteristics of intact 
agricultural commodities. While reflectance measurement permitted evaluation 
of surface appearance of commodities, it did not permit evaluations of interior 
characteristics of a sample. In many cases interior characteristics provide 
information about quality, maturity, and presence of certain defects that is 
impossible in reflectance measurements. With the system developed by Norris, 
chlorophyll content of the intact apple fruit could be indicated. 
Norris et al, (59) described the technique of rapid estimation of 
chlorophyll in apples and presented data to show the relationship of total 
extractable chlorophyll to instrument estimation in the intact fruit. 
Birth (3) describes an instrument designed to provide innumerable 
selection of wavelengths for detection of various pigments in the intact fruit, 
Such an instrument was the forerunner of the new ratio. spectrophotometers which 
enable rapid sorting of product for internal pigmentation or certain defects 
within a product. Birth's dual monochromator spectrophotometer was applied to 
apples, He states "that during a test with apples the average time per fruit 
was 20 seconds with one person handling the entire operation, With mechanical 
handling of the fruit a speed of approximately one fruit per second would be 
the maximum theoretical speed that could be obtained with the instrument."' The 
principal deterrent to very rapid sorting of apples is not the electronics 
involved in the instrument but the care with which the fruit must be handled to 
prevent bruising. 
In the yellow skin varieties of apples, not masked by anthocyanin pig- 
ments, chlorophyll disappearance internally is directly correlated with chloro- 
phyll disappearance externally. Sorting for the extent of green pigment 
internally by light transmittance technique therefore would also provide a good 
visual sort for surface color. 
Workman (93) reported that Grimes Golden did not develop acceptable color 
or edible quality on the tree, whereas Golden Delicious did. He suggested a 
direct relationship existed between the time required to attain the climacteric 
peak and the time to develop an acceptable color. 
Chemical Aspects 
Starch Content 
The relation of starch content of fresh apples to maturity has been 
extensively evaluated by research workers. Some have found it to offer con- 
siderable promise as an index of maturity, while others have had little success 
With “Lt, 
Griffiths and Potter (24) presented procedures for determining starch 
content of apples indicating a number of fractional components of the total 
starch content of the apple, 
Kidd et al. (34) pointed out that it was unlikely that the process of 
synthesis or condensation of starch proceeding in the tree should cease instan- 
taneously when the fruit is picked. His quantity/time curves for starch loss 
in apples were interpreted as follows: (1) the process of starch synthesis in 
progress on the tree continues for a short time, 1 or 2 days after harvesting, 
and then rapidly falls to zero; (2) during this time and subsequently, the pro- 
cess of degradation of starch in the apple is proceeding at a rate proportional 
10 
