Cranberry volatile compounds

The American cranberry (Vaccinium macrocarpon) is larger than the European cranberry (Vaccinium oxycoccous) but poorer in aroma. The European cranberry is a valuable raw material in the production of alcoholic drinks, liqueurs and jams in Scandinavia [35]. A few older studies report approximately 70 volatile compounds in cranberry [124, 125]. Cranberry aroma is characterised by several aromatic compounds, such as 1-phenylethanol, 2-phenylethanol,... 

In a companion study, M. Palma et al. studied the extraction of grape seeds with pure SF CO2 and analyzed the derivatized extracts by GC-MS. These extracts were found to contain volatiles such as aliphatic aldehydes in addition to fatty acids and sterols. Even though we used similar conditions for our SF extraction and GC-MS analysis, we were unable to detect any similar volatile compounds. To further investigate the presence of volatiles in the cranberry seed extract, we adapted a solid phase microextraction (SPME) method from the work of Jelen et al. who had earlier developed it for the characterization of volatile compounds in different vegetable oils. SPME followed by gas chromatog[raphy was performed on the headspace of the cranberry seed extract to test for the presence of volatile compounds. The GC trace failed to show the elution of any components for either the SF or Soxhlet extract. 

The berry or the small fruits consist of strawberry, raspberry, blackberry, black currant, blueberry, cranberry and elderberry. The volatiles responsible for the flavour of small fruits are esters, alcohols, ketones, aldehydes, terpenoids, furanones and sulfur compounds (Table 7.3, Figs. 7.1-7.7). As fruit ripen, the concentration of aroma volatiles rapidly increases, closely following pigment formation [43]. 

The simplest aromatic carboxylic acid is benzoic acid (8-72), which is relatively widespread in plant materials, mainly as 1-O-benzoyl-P-D-glucopyranose (see Section 4.3.3.3), but both compounds are non-volatile polar substances that do not have any impact on food flavour. In essential oils, benzoic acid is found in the form of flavour-active esters. Benzoic acid arises from cinnamic acid or cinnamoyl-CoA through side-chain shortening by a C2 unit. Its content in fruits and vegetables is generally very low, at around 0.05%. In cranberries it is present predominantly as 6-O-benzoyl-P-D-glucopyranose, known as vaccinin (see 4-92), in an amount of around 0.2%. Free benzoic acid is also present in a very small amount (about 0.0015%) in yoghurts where it results from hippuric acid hydrolysis. It is often also added to foods as a preservative. A typical example of a preserved product is table mustard, where concentrations of benzoic acid typically reach 1000 mg/kg. 

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