Effects of air injection during sap processing on maple syrup color, chemical composition and flavor volatiles

Air injection (AI) is a maple sap processing technology reported to increase the efficiency of maple syrup production by increasing production of more economically valuable light-colored maple syrup and reducing development of loose scale mineral precipitates in syrup and scale deposits on evaporator pans. These effects have not been evaluated, and the effects of AI on syrup chemistry and flavor are unknown. The color, chemical composition and flavor volatiles of syrup produced simultaneously with and without AI from a common source of maple sap were compared. The chemical composition of syrup produced with and without AI was within ranges previously published for maple syrup. Syrup produced with AI was significantly lighter in color than syrup produced simultaneously without AI using the same maple sap (p < 0.0039), but contained fewer volatile flavor compounds (p < 0.0015). The quantity of loose scale produced or thickness of scale deposited on evaporator pans did not differ significantly between the treatments (p < 0.1326, p < 0.9152). The results indicate that AI produced syrup with chemical composition consistent with pure maple syrup and increased production efficiency by increasing the amount of light-colored syrup produced, but not by reducing loose scale development or scale deposition.