Starch content in apple (Golden Delicious) skin and flesh was studied as a function of radiation dose (0, 0.5, 1, 2 and a 5kGy) after 8 weeks shelf life (16 C, 80-90% RH).
Starch was generally not found in the flesh with the exception of the 5 kGy sample. Starch grains were observed, however, in plastids of the epidermis and especially in the hypodermis in correlation with the radiation dose. 1 kGy dose caused a significant effect (p>99, 98%) on retardation of starch breakdown measured by electron microscopic morphometry and chemical analysis.
Analysis showed that increasing radiation dose increased glucose concentration in the flesh. In the skin the concentration of all three sugars, glucose, fructose and sucrose, increased with irradiation up to 2 kGy, but the decreased with higher doses.
Kovacs, E. and Keresztes, A.
"The Effect of Irradiation on Starch Content in Golden Delicious Apples,"
Food Structure: Vol. 8
, Article 9.
Available at: https://digitalcommons.usu.edu/foodmicrostructure/vol8/iss1/9