Handbook of Vanilla Science and Technology

Another issue is plastic vs. glass or metal containers. Traditionally, vanilla extract, which contains at least 35% ethanol, is stored in dark glass bottles to protect it from light-induced darkening of phenolics and avoid reaction with the alcohol during long storage. During short handling periods, common in industry and for restaurant use, it is appropriate to hold vanilla extract in plastic containers, to avoid problems with breakable glass. Many supermarkets also concerned with the breakability of glass keep vanilla extract in glass containers, but protect the glass bottles by placing them in protective boxes.

Some manufacturers specify Kosher certification (Jewish law) or Organic certification. These certifications designate yet another level of inspection and add to the product credibility. These certificates are not issued to cottage industry-made vanilla products.

12.6.2 Flavor components in the retail vanilla extracts

Although vanilla extract contains more than 300 compounds (Toth et al., Chapter 9), the most studied and commonly associated with vanilla extract quality are vanillin, vanillic acid, p-hydroxybenzaldehyde, and p-hydroxybenzoic acid. A label carrying the statement “Vanilla Extract” must contain at least one-fold vanilla. An average one-fold bourbon vanilla extract usually contains 0.1 to 0.2% vanillin, 0.01 to 0.05% vanillic acid, 0.01 to

0.03% p-hydroxybenzaldehyde, and 0.01 to 0.02% p-hydroxybenzoic acid. These values provide the standard acceptable ratios of these compounds in a one-fold vanilla extract. The concentrations of these compounds in vanilla beans have been the subject of debate, because vanilla grown in different regions does show variation in the compound ratios (Gassenmeier et al. 2008). However, for the purpose of this study, these values provide a useful guideline.

Figures 12.1,12.2,12.3 and 12.4 present the content of each compound, as a percent of the extract, in each of the tested samples. Figure 12.1 indicates arange of 0.01 to 0.8% vanillin in the tested extracts. The vanillin content is 0.1% or above in most samples. Samples showing vanillin content of 0.3 % and above (0.7, 0.5, 0.8 % in samples number 20, 43, and 47 respectively, for example) raise doubts about the authenticity of these extract preparations, suggesting supplementation with exogenous vanillin. Sample 20 lists “other natural flavors” (WONF) in the ingredients list. In the authors’ opinion, there is no provision in the standard of identity that allows for addition of other natural flavors to vanilla extract. By labeling the product “Natural Bourbon Vanilla”, rather than “Vanilla Extract”, the producer may not be subject to the standard of identity. Legally this may be a gray area and is certainly deceiving the consumers. Samples 46 and 48 were labeled as synthetic and were included in the analysis for comparison with those labeled as vanilla extract. These samples use synthetic vanillin or ethyl vanillin as the main flavor component. Ethyl vanillin was not analyzed in this study.

Fig. 12.1 Vanillin content in samples 1 to 65.

Fig. 12.2 Vanillic acid content in samples 1 to 65.

Fig. 12.3 p-Hydroxybenzaldehyde content in samples 1 to 65.

Fig. 12.4 p-Hydroxybenzoic acid content in samples 1 to 65.

The concentration of vanillic acid in the samples ranged from zero (no detectable vanillic acid) to around 0.025%, although there was considerable variation (Figure 12.2). However, most samples were below 0.01% vanillic acid. The concentration of p-hydroxybenzaldehyde in the samples ranged from zero to around 0.05%, with most samples containing below 0.01% (Figure 12.3). The concentration of p-hydroxybenzoic acid in the samples ranged from zero to around 0.13%, with most samples containing below 0.01% (Figure 12.4). Vanilla extract is often a blend of vanilla grown in different regions and we might expect variation in the tested compounds. However, an extract lacking some of these other flavor compounds suggests either a low amount, or even complete absence, of vanilla matter in the extract.

A graph illustrating the relative amounts of the four compounds in five of the samples is shown in Figure 12.5. The samples were chosen to represent the range in concentration of the flavor compounds observed. Sample #19 carries the name “Pure Bourbon Vanilla Extract”. Sample #12 is “Pure Vanilla Extract”. Sample #42 is named “Intensified Double Pure Vanilla Extract”. Sample #61 is “Pure Vanilla Extract” and Sample #65 is “Pure Vanilla Extract Madagascar Bourbon”.

Fig. 12.5 A comparison in the composition of samples representing vanilla extracts found in the retail market. Data used in the graph is from Table 12.1 and Figures 12.1 through 12.4. The percent p-hydroxybenzoic acid, vanillic acid, and p-hydroxybenzaldehyde contents are on the left axis and the percent vanillin content is on the right axis.