Physiologische symptomen van lage-temperatuur-bederf

At a safe temperature (over 13_C) in a green fruit of tomato the acid content increases and the respiration quotient CO 2 /O 2 < 1. When the fruit colour changes from green to yellow and red, the acid content decreases suddenly and the respiration quotient quickly increases to CO 2 /O 2 >1.
At a harmful temperature (well below +12_C) acid content and respiration quotient of a green fruit behave normally during the first few days, but then the increase in acid stops and CO 2 /O 2 becomes one. In green tomatoes with low temperature breakdown acid very slowly decreases after return to a safe temperature instead of increasing, and CO 2 /O 2 is about 1 instead of < 1; with the (imperfect) colour change the sudden drop in acid is absent and CO 2 /O 2 is 1.

No indications for an abnormal sugar respiration were found.

From these results and from data in the literature a working hypothesis was made that low non-freezing temperature causes an irreversible physical change in the protoplasm of the tomato fruit, so that normal protein hydrolysis does not take place, and no amino acids become available to form organic acids by deamination.