An inventory of methods suitable to assess additive-induced characterising flavours of tobacco products

Highlights

• We provide an inventory of methods to assess characterising flavours in tobacco.

• Flavour perception is subjective and needs consumer or expert panel assessment.

• Chemical analysis will quantify the amount of additive(s) imparting the flavour.

• Setting a reference is challenging, due to the many natural tobacco flavours.

Abstract

Background

Products with strong non-tobacco flavours are popular among young people, and facilitate smoking initiation. Similar to the U.S. Food and Drug Administration Tobacco Control Act, the new European Tobacco Product Directive (TPD) prohibits cigarettes and roll-your-own tobacco with a characterising flavour other than tobacco. However, no methods are prescribed or operational to assess characterising flavours. This is the first study to identify, review and synthesize the existing peer-reviewed and tobacco industry literature in order to provide an inventory of methods suitable to assess characterising flavours.

Methods

Authors gathered key empirical and theoretical papers examining methods suitable to assess characterising flavours. Scientific literature databases (PubMed and Scopus) and tobacco industry documents were searched, based on several keyword combinations. Inclusion criteria were relevance for smoked tobacco products, and quality of data.

Results

The findings reveal that there is a wide variation in natural tobacco flavours. Flavour differences from natural tobacco can be described by both expert and consumer sensory panels. Most methods are based on smoking tests, but odour evaluation has also been reported. Chemical analysis can be used to identify and quantify levels of specific flavour additives in tobacco products.

Conclusions

As flavour perception is subjective, and requires human assessment, sensory analysis in consumer or expert panel studies is necessitated. We recommend developing validated tests for descriptive sensory analysis in combination with chemical-analytical measurements. Testing a broad range of brands, including those with quite subtle characterizing flavours, will provide the concentration above which an additive will impart a characterising flavour.

Introduction

Smoking leads to severe health problems for both smokers and bystanders. According to the World Health Organization Framework Convention on Tobacco Control (WHO-FCTC), tobacco product attractiveness should be considered when taking regulatory measures, as tobacco products are commonly made to be attractive in order to encourage their use (Henningfield et al., 2011, WHO-FCTC, 2012). Smokers identify taste and aroma as important factors in the pleasure derived from smoking and for their choice of cigarette brand (DiFranza et al., 1994, Leatherdale et al., 2009, Levin et al., 1990, Talhout et al., 2009). For instance, the sweetness of cigarette smoke appeared closely related to satisfaction and pleasantness (Jaffe and Glaros, 1986).

Flavours are reported to mask the bitter taste of cigarette smoke, and provide a more appealing flavour (Bates et al., 1999, Fowles, 2001, SCENIHR, 2010, Sokol et al., 2014). For example, combustion of sugars generates caramel flavours in tobacco smoke, which give it a sweet taste appreciated in particular by adolescents (Talhout et al., 2006). Another example, menthol, provides flavour and a physiological “cooling” effect (Lawrence et al., 2011). When added in sufficient amounts, flavour can result in a strong non-tobacco flavour such as menthol, fruit or candy. Such strong flavours are popular among younger smokers. A recent study indicated that in the majority of cases, the first product used by experimenting youth is a flavoured product (Ambrose et al., 2015). Other studies show that younger smokers were up to three times likelier to have tried flavoured cigarettes than older, established smokers (Ashare et al., 2007, Feirman et al., 2015, Giovino et al., 1995, Klein et al., 2008, Lewis and Wackowski, 2006). Together with their marketing and packaging, this has raised concerns that they are targeted at youths (Carpenter et al., 2005, Kreslake et al., 2008, Lewis and Wackowski, 2006, O'Connor et al., 2007, Yerger and McCandless, 2011).

Based on their effect on tobacco product attractiveness, WHO-FCTC advises Parties of the FCTC to regulate, by prohibiting or restricting, ingredients that may be used to increase attractiveness (WHO-FCTC, 2012). Some countries already implemented legislation aiming at decreasing product attractiveness via flavour regulation. Brazil (RDC ANVISA N° 14) and Canada (BILL C-32) banned most flavours altogether, whereas other countries, such as the USA, banned cigarettes containing certain strong, characterising flavours (Tobacco Control Act, Sec. 907). In that case, flavour additives are allowed, but their level in the product or package should not result in a strong non-tobacco flavour such as fruit or candy. The new EU Tobacco Product Directive (TPD) also prohibits cigarettes and roll-your-own tobacco having a characterising flavour other than one of tobacco, arguing that these products facilitate initiation of tobacco consumption or affect consumption patterns (EU, 2014). A characterising flavour is defined as a ‘clearly noticeable smell or taste other than one of tobacco, resulting from an additive or a combination of additives, including, but not limited to, fruit, spice, herb, alcohol, candy, menthol or vanilla, which is noticeable before or during the consumption of the tobacco product.’

The TPD does not specify what the definition given above means in practice, and does not prescribe a method to measure characterising flavours. This paper therefore discusses tobacco flavour in general and the contribution of additives in specific. Building on that, we provide an overview of studies on tobacco products describing methods that would be suitable to assess whether an additive imparts a characterizing flavour other than tobacco. Next, we discuss the steps that need to be taken to translate these findings in a validated test suitable for legislative purposes. Finally, we give recommendations for future work on flavour regulation.