Chapters authored
Earthworms and Grape Marc: Simultaneous Production of a High-Quality Biofertilizer and Bioactive-Rich Seeds
Winemaking produces annually millions of tons of grape marc as a byproduct, which is a revaluable resource having many potential uses, including a nutrient‐rich organic soil amendment. However, its application as untreated raw material can damage crops owing to the release of phytotoxic polyphenols. This agronomic problems can be minimized by vermicomposting, as earthworms can partly digest polyphenols. This chapter reports the results obtained in the processing of grape marc derived from white wine through vermicomposting on an industrial scale to yield both a high quality organic, polyphenol‐free fertilizer and grape seeds as a source of bioactive compounds. Vermicomposting reduced substantially the residue biomass. In a very short‐term, the process yielded a nutrient‐rich, microbiologically active and stabilized peat‐like material that can be easily separated from the seeds by sieving. The isolation of the seeds eliminates the polyphenol‐associated phytotoxicity from the vermicompost and left those seeds prepared to be easily processed to get different bioactive compounds, mainly rich‐polyphenols extracts but also rich‐fatty acids seed oil. The procedure described is effective, simple, environmental‐friendly and economical, and can easily be scaled up for industrial application yielding a variety of added‐value products from the initial grape marc.
Part of the book: Grape and Wine Biotechnology