Maple syrup calorie, vitamin and mineral content are the same in all grades. Maple syrup is a good source of manganese, an essential mineral for producing antioxidant enzymes in the mitochondria and for the metabolism of carbohydrates, amino acids and cholesterol. Maple tree sap, from which the syrup is prepared, has a seasonal variation in antioxidants and and DNA-protecting content, so that light-colored grades of syrup collected early in the season have different antioxidants from dark-colored grades collected later.
Nutritional Value
The U.S. Department of Agriculture recognizes only one set of nutrition values for all grades of maple syrup. A serving of 3 tbsp. of maple syrup of any grade will boost a stack of pancakes with 156 calories that are almost all sucrose sugar, 61 mg of calcium, 13 mg of magnesium, 127 g of potassium, 1.7 mg of manganese, 0.8 g of zinc, 7 g of sodium, 0.7 mg of riboflavin, 1 mg of choline, and traces of other vitamins and minerals. For perspective, the Linus Pauling Institute reports that the recommended daily allowance of manganese for children up to age nine is 1.5 mg; for females up to age 18 the dosage is 1.6 mg.
Antioxidants
Phenolic antioxidants are free radical scavengers that bond to oxides inside the body and prevent them from damaging tissue. In 2010, researchers Liya Li and Navindra P. Seeram reported finding 23 phenolic antioxidants in maple syrup. Dr. Seeram speculated that when sugar maples are wounded during sap collection, they secrete phenolic antioxidants as a defense, and noted that some antioxidants are always present in sap just below the bark, as the bark is constantly exposed to sunlight.
U.S. and Canadian Grading
Maple syrup is graded on the basis of color, which reflects the time of season when the maple sap is collected. Early season saps are light colored and have a more sugary, less maple flavor. The USDA recognizes Grade A light amber, medium amber and dark amber table syrup, plus two lower stronger flavored levels of Grade B for uses such as industrial baking. The Canadian government recognizes Grade AA for light amber and Grade A for medium amber, then Grade B for dark amber, plus industrial grades C and D. By law, all maple syrup is the same density, although consumers perceive darker syrups as thicker.
Antioxidants by Season
Among the 23 maple sap antioxidants, various ones are collected in different sap seasons through the winter and persist differently among the syrup grades after processing, so there is no graded color of maple syrup that is the best antioxidant source. In 2006, researchers wrote in "Food Chemistry" that the DNA-protecting properties of some maple sap antioxidants were greatest in the third quarter of the winter collection season, when dark color Grade B sap is harvested, but best survived through boiling and processing for the first quarter's light color Grade A sap. For other antioxidants, the DNA-protecting activity was greatest in the first quarter's lightest sap and fourth quarter's darkest sap products, but survived processing best in the third quarter's finished syrup.
References
- Oregon State University: Linus Pauling Institute: Manganese
- "Food Chemistry"; Antioxidant, Antiradical and Antimutagenic Activities of Phenolic Compounds Present in Maple Products; Mylene Theriaulta, et al.; 2006
- USDA Nutrient Database for Standard Reference
- "Journal of Agriculture and Food Chemistry"; Maple Syrup Phytochemicals...; Liya Li and Navindra P. Seeram; Oct. 29, 2010
- "Vancouver Sun"; Maple Syrup Rich in Antioxidants: Study; Randy Boswell; March 22, 2010
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