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Chapter 15. Authentication of Vanilla Products
Jens-Michael Hilmer, Franz-Josef Hammerschmidt, and Gerd Lösing
Introduction
Vanilla belongs to the most valued as well as the most expensive spices of the world. It represents the most important aromatic flavor, whose production constitutes a multimillion dollar a year for the industry (Krueger and Krueger, 1983). Worldwide production of vanilla observed is 2000 metric tons per year. Vanilla extracts are used extensively in chocolate and baked products, but most commonly in ice cream. The main flavor-active ingredient of vanilla extracts is vanillin. Industrial chemical synthesis of vanillin started more than 130 years ago (Tiemann and Haarmann, 1874). It is one of the most widely used flavoring components currently used in the flavor industry. The total consumption of vanillin is estimated to be at 12,000 metric tons per year (Eurofins Newsletter, 2003), about 82% for flavor purposes, 5% for fragrances and cosmetics, and 13% for pharmaceutical intermediates. The demand for it far outweighs its natural supply. Bensaid (Eurofins Newsletter, 2003) states that only 0.33% of the consumed vanillin originate from vanilla beans. Natural vanillin can be 100 times more expensive than vanillin from synthetic origin—in some years even more, depending on the harvest (Eurofins Food Newsletter, 2007). This price difference in combination with the “biotrend” and the demand for natural products has induced the flavor industry to develop alternative sources of natural vanillin, for example, based on the biotransformation of natural compounds.
Therefore, adulteration of vanilla extracts is a major problem in the commercial market for this product category. Consequently, there are plenty of governmental regulations concerning the authenticity of vanilla extracts to detect adulterations and to avoid cases of fraud.
In order to protect food manufacturers and consumers from adulteration of vanilla products, it is necessary to have powerful analytical tools available to prove authenticity of the respective vanilla products. Depending on the nature of the expected fraudulent activities as well as the specific product categories affected (such as vanilla beans, vanilla extracts, vanilla flavors, or vanilla food products), different strategies to detect these adulterations are applied.
There are numerous possibilities known about how the legal and sensory status of a vanilla product can be affected:
• Addition of non-vanilla-derived compounds to impart flavor; this includes:
• nature-identical/artificial vanillin from synthetic origin
• artificial ethyl vanillin
• tonka bean extract
• coumarin
• Adulteration of vanilla beans: addition of iron particles such as nails or even elementary mercury in order to increase the weight of the very precious vanilla beans (this was especially a topic, when vanilla bean prices were very high and reached several hundred dollars a kilogram some years ago).
• Adulteration by incorrect botanical origin: there are more than 100 different vanilla species known, and only three of them have a commercial relevance: Vanilla planifolia Jacks./Andrews, Vanilla tahitiensis J.W. Moore, and Vanilla pompona Schiede. For example, Bourbon Vanilla is related to V. planifolia species.
• Adulteration by incorrect geographical origin: since the geographical origin \of vanilla beans is relevant for regulatory reasons [e.g., to claim “Bourbon Vanilla” is only allowed when using vanilla extracts derived from vanilla grown in Madagascar, Reunion Island (formerly called “Ile Bourbon”), the Comoros, Seychelles, or Mauritius].
• Correct concentration indication of x-fold vanilla extracts: The amount of vanilla beans used for the production of vanilla extracts is relevant, for example, in the US market. This is expressed in the “Standard of Identity” (FDA Code of Federal Regulations). A total of 100 g of vanilla beans used for the production of 1 kg vanilla extract gives a so-called onefold extract.
The analytical methods that could be applied to indicate an authentic vanilla product can be based on the identification of single ingredients as well as on the combination of ingredients typically present in vanilla. As an example, the main flavor-active compound present in vanilla, vanillin, can be monitored specifically with methods such as GC, HPLC, IRMS, or specific NMR methods (see below). In addition, the presence of typical by-products in vanilla, such as vanillic acid, p- hydroxybenzaldehyde, or p-hydroxybenzoic acid, is determined. The ratio of these components is also used to judge the authenticity of vanilla and vanilla products. Also, the absence of compounds, which are usually not present in vanilla, such as (artificial) ethyl vanillin or vanillin derived from chemical synthesis can be used to assess the quality. In order to detect adulterations indicated, various specific analytical methods were developed and presented in the following sections.
Both consumers as well as food manufacturers can be protected from fraudulent activities by using state-of-the-art comprehensive analytical techniques for the evaluation of the authenticity of food raw materials as well as food products.