Progress 09/01/08 to 08/31/09

Outputs
OUTPUTS: New maple sap and syrup processing practices designed to increase the profitability and efficiency of maple syrup production are often put into use without rigorous scientific investigation of the potential effects on the quality or flavor of the syrup produced. Reverse osmosis (RO) is a process used by many maple producers to increase the profitability of maple production. RO is typically used to concentrate maple sap from 2 to 8-12% sugar prior to heating in an evaporator. This can substantially reduce the cost of producing maple syrup by reducing the amount of water that must be removed by heat-driven evaporation and thus the amount of time and evaporator fuel required to process sap into syrup. Because maple syrup's characteristic flavor and color develop during heating in the evaporator, the reduction in heating time required to produce syrup from sap concentrated by RO has the potential to result in substantial impacts on the quality of the syrup produced. Our previous research has shown that concentration of sap with RO up to 15% sugar had no significant impacts on the quality or flavor of syrup. However, in response to increasing fuel costs, many producers are now choosing to concentrate sap to much higher concentrations, often 21-25%. This new practice has a much greater potential to impact syrup quality than the more moderate use of RO. Thus, the overall objective of this project was to determine the effects of producing syrup from sap concentrated to very high sugar concentrations with RO on the chemical composition and flavor of the syrup produced. We conducted controlled experiments in which maple syrup was produced simultaneously from the same maple sap that had been concentrated by RO to two levels of sugar concentration: 8% (standard) or 22% (very high). Five replications of the experiment were conducted during the 2009 maple production season. The physiochemical properties (pH, conductivity, color, and density) and chemical composition (including inorganic minerals, carbohydrates, and volatile flavor and aroma compounds) of the maple syrup produced in the experiments were subsequently analyzed. In addition, sensory evaluation experiments were conducted to evaluate the effects of the treatments on the flavor of the syrup produced. The data collected were then analyzed statistically to determine if significant differences existed in the chemical composition or flavor of syrup produced from sap concentrated to 22% (very high level) or 8% (standard level) by RO. The results obtained were presented to maple producers, industry members, scientists, and extension professionals from throughout the maple producing region at the North American Maple Syrup Council and International Maple Syrup Institute Conference in October 2009. The results will also be reported to stakeholders at three Vermont Maple Conferences in January 2010. An article to disseminate results to maple producers and industry constituents is being prepared for publication in the industry journal, the Maple Syrup Digest, and a manuscript for submission to a peer-reviewed journal for dissemination to the scientific community is also in preparation. PARTICIPANTS: Timothy Perkins (PI) provided overall project planning and guidance throughout the work, served as the financial manager, and oversaw the analysis of data and preparation of reports. Abby van den Berg (Co-PI) was responsible for the day‐to‐day planning, preparation, and execution of the experiments, and assisted with data analysis and report generation. Technician Mark Isselhardt assisted in the preparation and execution of the experiments. TARGET AUDIENCES: The primary target audience for this project is maple producers who currently use, or are considering using, reverse osmosis to increase the profitability of maple syrup production. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The results from the experiments conducted indicated that maple syrup produced with sap concentrated to 22% by RO was significantly lighter in color than syrup produced from the same sap concentrated to 8%. However, there were no other significant differences in the properties, chemical composition, or flavor profiles of the syrup produced. In addition, in sensory evaluations panelists were unable to detect a difference in flavor between the syrup produced simultaneously with the same sap concentrated to 8% and 22%. The results indicated that producing syrup with sap concentrated to very high levels with RO does not have any greater impact on syrup chemical composition or flavor than producing syrup with sap concentrated to standard levels. Maple syrup production is an important agricultural enterprise for thousands of producers in Vermont and throughout the maple producing region of the US and Canada. In many cases maple syrup production supplements other agricultural endeavors, such as dairying, as a vital source of income to help maintain viable, profitable farms. It is thus critical to investigate and establish practices that maximize yields and profitability of maple syrup production, and also maintain the longterm sustainability of maple syrup production and the maple resource itself. The goal of our project was to investigate the effects of the relatively new practice of producing syrup with maple sap concentrated by reverse osmosis (RO) to very high (much higher than standard) sugar concentrations on syrup quality and flavor to determine if it is an acceptable, effective practice to increase the profitability of maple syrup production operations. The effects of any new practice used to increase the efficiency of maple syrup production on the composition and flavor of syrup are of concern, as maple syrup is marketed as a pure and natural product with highly prized characteristic flavor and color properties. Results from the experiments we conducted showed that the quality, composition and flavor of maple syrup made with sap concentrated to a very high sugar level by RO (22%) did not differ from syrup made from the same sap concentrated to a more moderate, industry standard level (8%). The results of our project indicated that maple producers can concentrate sap with RO to very high sugar levels to increase the efficiency and profitability of maple production, without significantly affecting the quality of the maple syrup produced.

Publications

• Perkins, T.D. and A.K. van den Berg. 2009. Maple Syrup - Production, Composition, Chemistry, and Sensory Characteristics. pp. 102-144. In: S.L. Taylor (Ed.) Advances in Food and Nutrition Research. Volume 56. Elsevier, New York.