The effects of NaOH treatments of grape-marc, vinasse, and wheat-straw mixtures on their degradability in vitro

Abstract The utilization of exhausted grape marc and vinasse, two polluting wastes from alcohol distilleries that process grape marc, is proposed. A mixture of these materials with wheat straw, in various ratios, was submitted to wet treatments with 7–15% NaOH on total dry matter at 70°C. By means of these treatments a double result was obtained: an increase in the digestibility of the two solid components and utilization of the valuable compounds contained in vinasse (which is a liquid containing about 5% d.m.). By limiting NaOH to 10% on total d.m., a final dried product with about 45% in-vitro digestibility and less than 20% crude fibre was obtained, which could probably be utilized as a feedstuff for ruminants. Further studies and larger-scale experimentation will be necessary in order to evaluate the economic suitability of the whole process.