Abstract:

In this study, the peanut variety BaiRiHong (Arachis hypogaea L.) was selected to investigate the changes of main
physiological reactions and protein during germination. The results showed that the germination percentage was 98.33% and the
average shoot length was 67.59 mm after 96 hours of germination. The content of dry matter showed an decreasing tendency:
it decreased rapidly within the first 48 hours and from the 60th to the 84th hours while the changes were not significant (P ＞
0.05) within these hours: the 48th to the 60th hours and the 84th to the 96th hours. The respiration intensity tended to increase,
that is, the increase was sharp between the 12th and the 24th hours, then slow and reached a pleatau. The soluble sugar content
reached minimum and maximum at the 36th and the 84th hour, respectively, which was 80.75% and 121.24% of non-germinated
control. The soluble protein content followed a decrease-increase-decrease pattern and reached its minimum value at the 48th
hour, which was 79.07% lower than that of non-germinated control. The contents of peptides and free amino acids showed
an increasing tendency, and at the 96th hour were elevated 1.18 and 6.33 times, among which the human essential amino
acid content increased 7.18 times while the proportion in total amino acids changed from 28.69% to 32.02%. The contents
of the limiting amino acids Thr and Met increased 6.88 and 9.27 times while Try was not detected. These results showed that
this germination process could alter the amino acid composition and improve the nutritional quality of peanut protein. The
activities of protease and endopeptidase increased steadily throughout the germination period while the latter enzyme reached
its maximum at the 84th hour. Correlation analysis of various parameters revealed that the major physiological changes led to a
considerable effect on peanut endogenous protease and thus, affected protein metabolism.

Key words: peanut, germination, physiological indicators, protein, metabolism