Maple syrup flavor compounds

Overall, dozens of compounds are involved in the development of the characteristic flavors found in maple syrup. The number of compounds, the different sap to syrup processing involved, the wide range of maple syrup flavor and intensity, and somewhat frequent off-flavors all complicate the understanding of the flavor of maple syrup. 

It takes 20 to 40 L of sap to yield one liter of maple syrup. To remove the water, you could freeze the sap, as the Native Americans did 300 years ago. The ice that forms is pure water by discarding it, you increase the concentration of sugar in the remaining solution. Large-scale operators today use reverse osmosis to remove about half of the water. The remainder must be boiled off. The characteristic flavor of maple syrup is caused by compounds formed on heating, such as... 

Classify the following as element, compound, or mixture, and justify your classifications salt, stainless steel, tap water, sugar, vanilla extract, butter, maple syrup, aluminum, ice, milk, cherry-flavored cough drops. 

Salt, sodium chloride classification compound. Stainless steel, mix of iron and carbon classification mixture. Tap water, dihydrogen oxide plus impurities classification mixture. Sugar, chemical name sucrose classification compound. Vanilla extract, natural product classification mixture. Butter, natural product classification mixture. Maple syrup, natural product classification mixture. Aluminum, metal classification in pure form—element (sold commercially as a mixture of mostly aluminum with trace metals, such as magnesium). Ice, dihydrogen oxide classification in pure form—compound when made from impure tap water—mixture. Milk, natural product classification mixture. Cherry-flavored cough drops, pharmaceutical classification mixture. 

It should also be noted that maple syrup contains high molecular weight polysaccharides (80) which probably are also partially degraded during processing and thus can serve as sources for additional flavor compounds. 

Alii, I., Akochi, K. E., and Kermasha, S. (1992). "Flavor Compounds in Maple Syrup. Developments in Food Science" Vol. 29, pp. 131-140. Elsevier, Amsterdam. 

Belford, A. L., Lindsay, R. C., and Ridley, S. C. (1991). Contributions of selected flavor compounds to the sensory properties of maple syrup.. Sens. Stud. 6,101-118. 

Nishimura and Mihara (1990) investigated 2-hydroxy-2-cyclopenten-l-ones in a steam-distilled coffee extract and identified ten compounds of this class, seven of them being reported for the first time in a natural flavor and some even being original chemicals. Procedures used for their syntheses are described. All the 2-hydroxy-2-cyclopenten-l-ones were also identified in a model reaction, when sucrose, the major component of green coffee, was heated with alkali in aqueous solution. Some had been previously found in maple syrup or tobacco. We are reminded that Gianturco et al. (1963) mentioned for the first time the presence of these typical, sweet, caramel-like and burnt compounds in a roasted coffee extract. 

The most Important use of body odors in disease diagnosis relates to the infant diseases involving errors in amino acid metabolism. Strong and unusual odors are manifest in the breath, sweat, and urine of these individuals. Table II summarizes several known acidurias, the amino acids that are not properly metabolized, and the odors associated with the compounds which accumulate and can be detected in the urine ( ). In the case of the Maple Syrup Urine and Oasthouse syndrome, the keto- and hydroxy- acids which have been identified may not be responsible for the observed maple and celery/yeast odors (.9). Alternatively, these odors could be the result of conversion of 2-keto-butyrlc acid to methyl-ethyl-tetronlc acid (Slusser s lactone) which is used as an extender in maple and celery flavors and has a maple syrup-like odor (R. Soukup, personal communication). With these acidurias it is imperative that an immediate diagnosis is made, since corrective diet can prevent the brain damage that results from these diseases. This is readily done on an olfactory basis which can subsequently be supported by gas chromatographic... 

QHjOj, Mr 112.13 cryst. with a spicy, caramel-like odor resembling that of liquorice, mp. (monohydrate) 106 °C soluble in alcohol (25%), water (2.5%), but hardly soluble in petroleum ether it is formed from glucose by the Maillard reaction and is present in the flavor of thermally prepared foods such as maple syrup, bread, coffee, roasted nuts, and roast pork. It is mainly obtained from beech wood tar and used as a flavor compound, e. g., for the above-mentioned aromas. 

The characteristic flavor of maple syrup is caused by compounds formed on heating, such as... 

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