Saponin Profile of Green Asparagus Genotypes

Abstract

Among the phytochemicals found in green asparagus, phenolics and saponins represent the major groups of bioactive compounds. The first are mainly related to the antioxidant activity of this product; and the distinct saponins detected in green (triguero) asparagus influence both its organoleptic and bioactive properties. The main objective of the present work is the characterisation of the saponins profile from distinct genotypes of the green asparagus. Their analysis by HPLC-MS (High Performance Liquid Chromatography-Mass Spectrometry) have revealed that the content and composition of saponins from green asparagus are significantly different from those of the commercial hybrids. Hence, in green asparagus, there have been identified several saponins that distinguish it from the rest and that can be an adequate parameter for the determination of not only its organoleptic properties but also its major or minor functional quality. Saponins total content was about ten times greater in the green asparagus than in the commercial hybrids. Besides, in the green asparagus there have been detected significant quantities of several saponins that are not present in commercial hybrids. Typical saponins from the green asparagus are steroidal saponins derived from diosgenin, and mostly consist of protodioscin. However, the analysis of the green asparagus samples has revealed the presence of six naturally occurring saponins, neither of them being diosgenin derivatives but sarsapogenin glycosides.