Bioethanol Production as an Alternative End for Maple Syrups with Flavor Defects

The purpose of this paper is to demonstrate the validity of an alternative route to valorize declassified maple syrups affected by flavor defects such as ropy maple syrup (RMS) and buddy maple syrup (BMS) as feedstocks for ethanol production. An acid hydrolysis treatment (0.1 M, 0.5 M, 5 M, and 10 M) was performed on the RMS to break the polysaccharide chains which are responsible for the flavor defect. The sugars and inhibitors composition of these hydrolysates were analyzed by ion chromatography and ion exclusion chromatography, respectively. Maple syrup samples were fermented by Saccharomyces cerevisiae for 96 h at 30 °C, and ethanol content was measured to determine the kinetic parameters of the process. RMS and BMS demonstrated a good potential to be used as feedstocks to produce ethanol achieving high efficiencies (RMS: 90.08%; BMS: 93.34%). The acid hydrolysis (25 min, 50 °C, with the addition of 5 M sulfuric acid solution) was effective to maximize ethanol production when using RMS as feedstock. To the best of our knowledge, it is the first time that such an approach is used to valorize declassified maple syrups