Effects of Jatropha curcas L. (Euphorbiaceae) composts on biochemical, phytochemical and nutraceutical quality of sorghum (Sorghum bicolor (L.) Moench) seeds

Abstract

A study on the potential for agronomic valorisation of Jatropha curcas co-products in rainfed agriculture was conducted in Burkina Faso to determine the impacts of compost-based by-products of Jatropha on the nutritional quality of the sorghum seeds produced. The effect of 13 composts was evaluated and compared to a control. Sorghum seed parameters determined were total phenolics, total flavonoids, starch, total sugars, phorbol esters and antioxidant activities measured with DPPH and FRAP protocols. The results have showed a statistically significant difference between the treatments for all parameters. Correlations between the different parameters mean a simultaneous improving of biochemical parameters of sorghum. The ferric reduction ability power was significantly and positively correlated to total phenolics (r = 0.792) and flavonoids (r = 0.602) content. The analysis of the main components has enabled the various treatments to be divided into 4 groups. Flavonoid content and FRAP activity are closely related to the treatment BM+CP. The treatments for the control group have improved total polyphenol content and DDPH activity. The others groups have improved starch and carbohydrate content. The phorbol ester dosage revealed no contamination of sorghum seeds. These results suggest that Jatropha by-products compost can be used as an alternative or complement to chemical fertilizers for soil fertility improvement.