Sorghum grain germination as a route to improve kafirin digestibility: Biochemical and label free proteomics insights

Kafirin, the sorghum grain storage protein presents lower digestibility compared to its cereals counterparts. Germination has been proposed as an adequate bioprocessing method to improve seed protein digestibility. Here, germination was rationalized so as to evenly sample germinated seeds and the dynamic changes of the proteome and several biochemical markers was connected for the first time with the in vitro protein digestibility of germinated seeds. Free sulfhydryl groups increased during germination and in vitro protein digestibility enhanced. The dynamic in abundance of several enzymes out of which 3 cysteine proteases were found to coincide with appearance of aqueous soluble peptides derived from kafirin at boot time of their degradation. The study provides deep information about the molecular events occurring during sorghum seed germination and reveals potential biomarkers of the kafirin proteolysis. It points a way to improve sorghum nutritional value through controlled germination.

Automated summary

Germination is a method to improve the digestibility of kafirin, the sorghum grain storage protein. During germination, the content of free sulfhydryl groups increased, leading to enhanced in vitro protein digestibility. The study also identified the dynamic changes of enzymes and the appearance of aqueous soluble peptides derived from kafirin, which serve as potential biomarkers of kafirin proteolysis. Controlled germination can be a way to improve the nutritional value of sorghum.