Hop green sprouts preservation and valorisation as semi-finished and finished products: impact of different treatments on microstructural, physical and chemical traits

Hop plants, produce edible sprouts, with interesting qualities, but their conservation is very poor. In this study, the effect of different treatments (freezing, blanching, sterilization and pasteurization) on two cultivars (Cascade and Nugget) of green hop sprouts were evaluated. Microstructure, physical analyses (texture and colour), enzymatic activity, DPPH activity and nuclear magnetic resonance (1H-NMR) were utilized for the assessment of the product quality. Results indicated that freezing caused severe cellular and tissue damages. The results on colour and DPPH activity after treatments are cultivar-dependent. From 1H-NMR analysis, the samples with spectra more similar to raw one are blanched and blanched + freezing. In conclusion, blanched + freezing samples resulted the best choice for the technological and nutritional quality of hop sprouts and for a conservation of them; among final products obtained by thermal treatments, the pasteurized samples seemed to be the one that better preserves hop sprout quality.