Over the last few decades, the prevalence and incidence of diseases related to excessive weight gain, such as obesity, type 2 diabetes, and hypertension, have increased worldwide. For example, globally, the number of people who are living with diabetes has nearly doubled between 1980 (4.7%) and 2014 (8.5%) [1
]. Those incidences have been linked to excessive sucrose intake. Dietary choices are a key factor that influence this global burden [2
]. The World Health Organization (WHO) published a guideline that suggests limiting the intake of sugar to 10% of the daily total energy intake [3
]. They even recommend to further reduce the sugar intake to 5% [4
]. Reducing the sugar content in foods is an important goal in many countries, e.g., Belgium, Italy, UK, and Germany [5
]. To achieve this goal, there are many national projects to promote healthy eating. Examples are the ‘healthy weight strategy’ in the UK [6
] or the ‘national reduction and innovation strategy’ in Germany [7
The preference of mankind for sweetness is innate before birth [8
]. Exposure to sweet beverages and sugary foods during childhood leads to an increased preference for sweet tastes [9
]. In addition, nutrition is a habitual behavior and difficult to change [10
]. Therefore, one strategy is to use sweeteners with similar characteristics (e.g., taste and processing properties) as the common sugar called sucrose, but with fewer calories. Depending on the level of sweetness in relation to sucrose (international reference of sweetness potency = 1), sweeteners are classified into two groups, namely nutritive and non-nutritive sweeteners. Until now, most nutritive sweeteners have had a similar or lower sweetening potency as sucrose, but these sweeteners do not lower the calorie content of food substantially [11
]. One exception is, for example, erythritol, which is a non-caloric sweetener [12
]. Non-nutritive sweeteners have a much higher sweetening potency. Thus, only small quantities are necessary to achieve the required sweetening level, and therefore the calorie content added to the food is low [13
Within the category of sweeteners, stevia is a natural non-nutritive sweetener, while xylitol and erythritol are low-caloric sugar alcohols [14
]. Xylithol and erythritol are sourced from natural origin. Stevia, xylitol, and erythritol are already available in supermarkets and contained in foods, while allulose is not available in Germany. Stevia has, compared to sugar, about 300 times the sweetening potency and a liquorice-like taste of its own [15
]. The consumption of stevia causes no known consequences for human health as long as it lies within the limit of 4 mg/kg of body weight/day [16
]. There is no known effect on blood glucose levels, and stevia does not cause caries and is calorie-free [17
]. Xylitol, also known as birch sugar, is not usually made from birch wood but from agricultural residues such as corncob pomace, straw, and hardwoods. It is not caries-causing and has about half the calories of conventional sugar. The sugar alcohol xylitol does not affect insulin levels, but in larger quantities it can have a laxative effect [18
]. Erythritol occurs naturally only in small quantities in fruits, vegetables, and cheese and therefore mostly comes from industrial production [19
]. In various biotechnological processing steps with the help of fungi, erythritol is produced from carbohydrates such as glucose or sucrose. Erythritol does not promote caries, is calorie-free, and does not affect insulin levels, but in larger quantities it can have a laxative effect [18
Allulose (also known as d-allulose, psicose) is a novel rare sugar. Allulose occurs naturally, for example in figs, kiwis, and raisins, but only in very small quantities. Using enzymes, the rare monosaccharide allulose can be obtained from conventional beet sugar or maize through enzymatic conversion [20
]. As a sugar, allulose has similar functional properties as conventional sugar. It is available in crystalline powder and is easily dissolved in water [21
]. The sweetness of allulose is about 70% that of sucrose. Due to its low calorific value of 0.4 kcal/g [22
], it has just 10% of the calories of sucrose. Allulose melts at 90 °C and forms caramel [23
]. Additionally, allulose has many health advantages in comparison to conventional sugar, including no influence on blood glucose levels (glycemic control). Furthermore, diets supplemented with allulose are suggested to prevent obesity and diabetes [23
]. One main advantage of allulose is that it has a typical sugar taste [23
], and sometimes a hint of caramel is associated with it. In 2012, the US Food and Drug Administration approved allulose (GRN No. 400) as safe. Thus, it is allowed to be used as an ingredient in a variety of foods and nutrition supplements in the US. Allulose has also received approval in Mexico, Japan, Singapore, and South Korea [24
]. In Europe, allulose is currently in the approval process at the European Food Safety Authority (EFSA), as it falls under the novel food regulation as a previously unavailable food.
To learn more about the market potential of sweeteners, it is important to investigate consumer preferences of sweeteners. German consumers perceive erythritol as artificial (88%) and stevia as in-between artificial (49%) and natural (51%). Only xylitol is perceived as natural, by 65% of consumers (the researcher in this study also mentioned the German name ‘Birkenzucker’, or ‘birch sugar’ in English, which may have led to a naturalness bias) [25
]. Polish consumers said that the main reason to limit the sugar intake was due to weight control. To limit the amount of sugar in their diet, they used sweeteners instead [26
]. In Germany, one study found out that ‘fewer calories’ is seen as the most important benefit of sweeteners [25
]. A review about natural sweeteners revealed that consumers are eager to eat foods consisting of natural ingredients but do not want to compromise on taste [15
]. In line with that is the research on Canadian consumers who judge taste and naturalness as the most important point of consideration when buying sugars or sugar substitutes [27
]. Moreover, frozen desserts containing natural non-nutritive sweeteners did not fulfill the expectations of consumers. Consumers judged taste as more important than perceived healthiness [28
]. Another study showed that consumers’ healthiness perception of sweeteners varied widely. High fructose corn syrup (64%) and aspartame (52%) are perceived as less healthy than table sugar, while almost half of the consumers perceived raw sugar (48%) as healthier than table sugar [29
]. In their research, Goodman et al. [29
] concluded that the perceived level of naturalness and not the calorie content might be related to consumers’ perception of sweetener healthiness. Moreover, consumers indicated that they wanted to reduce their intake of sugar compared to low calorie sweeteners [29
]. Additionally, sweeteners are perceived as risky [30
]; thus, parents think sweeteners are not safe for their children to consume [31
], which affects the acceptance of sweeteners [30
In the marketing of sweeteners, a wide variety of characteristics could be used in communication. Conceivable topics include, for example, calories, naturalness, taste, or health aspects. So far, it is not known which of these characteristics consumers prefer or which characteristics consumers look for when buying sweeteners. These insights are of particular importance in the context of reformulating food recipes and therefore help food producers to decide which sweetener to use in their food products. Sweeteners are important in terms of reformulation because they can reduce the calorie content and make food products healthier, for example, more tooth-friendly. As an approval by the EFSA of allulose is expected in Europe, it is necessary to analyze which properties of sweeteners are important for consumers. To analyze consumer preferences regarding different characteristics of four sweeteners (allulose, stevia, xylitol, and erythritol), an online survey including a choice experiment was conducted. The data were analyzed using a mixed logit model. The results will allow companies to tailor their communication strategy based on consumer preferences. This is especially important for companies who want to sell or use allulose in their foods. Allulose is considered as an important ingredient in food in the future. The global market size is projected by 2027 to reach US $
27 million [32
This research is the first work to examine the importance of allulose characteristics in comparison to three other sweeteners. The results reveal that taste is the most important attribute when purchasing sweeteners. This result is in line with earlier findings by Mintel [27
]. A study which included frozen dessert (consisting of non-nutritive sweeteners) also showed that taste is more important than perceived healthiness [28
]. Research of other food products also showed that taste has a major influence on choice [46
]. The second-most important attribute is the base product. It is the source the sweetener is made of and suggests a hint of naturalness of the product. This result is in line with earlier research which reported that naturalness is an important aspect of foods [48
]. It is interesting that the ‘influence on blood glucose level’ is the third-most important attribute. Price, dental health, and calorie content followed as being equally important to consumers. In comparison, earlier research showed that fewer calories are an important characteristic for consumers when choosing sweeteners [25
]. This difference could be due to different data collection approaches. The results of the current research are based on hypothetical choice decisions, and thus relative importances, while the results from Ears and Eyes [25
] are based on judgments on a five-point Likert scale.
The results indicate that a ‘typical sugar taste’ is the most preferred taste, followed by ‘sweet taste’. Research showed that a preference for sweet taste can be observed by all people independent of their age [49
]. The other attribute levels, which consist of an aftertaste (caramel or liquorice), are not favored by consumers. The communication of attributes that further describes the sugar taste profile (e.g., hint of caramel) will not lead to a positive rating; even the wording ‘typical sugar taste with a hint of caramel’ has a negative rating. It is the attribute level with the overall highest negative part-worth utility. This clearly shows that consumers prefer a typical sugar taste or a sweet taste.
It is surprising that the ‘extracted from sugar beets’ level is not significant, as it is the vegetable from which sugar is often made. Research has shown that naturalness is an important aspect when buying foods [48
]. Extracting ingredients from sugar beets for sugar production could fulfil the consumers’ desire for naturalness. Goodman et al. [29
] concluded that naturalness is the aspect that consumers use when judging the healthiness of sweeteners and not the calorie content. In the current study, the stevia plant is the most-preferred base product. One possibility could be that the base product ‘stevia’ is also the product name with which it is sold and is therefore well-known by consumers. However, stevia has a sweet taste with a liquorice note, which in fact was not preferred by consumers. These contradicting results show that consumers might have very little knowledge about the production of sweeteners. Providing consumers with information about the production process could increase their acceptance of sweeteners from natural base products. Another explanation could be that consumers rate the base product ‘stevia plant’ as natural but do not prefer the taste of stevia.
‘Influence on blood glucose level’ is not significant. About 8 million Germans have diabetes, and a further 2 million have diabetes but are not diagnosed. It is expected that by 2040, around 12 million Germans will suffer from diabetes [50
]. This currently makes up 10% (2040: 15%) of the German population who must pay attention to the influence on blood glucose level (glycemic control) when eating. Thus, it can be predicted that this level might gain importance in the near future. Allulose could be a good choice for glycemic control, as research showed that in healthy individuals, it does not raise blood glucose and insulin levels [51
]. Further, if small quantities of allulose are added to high glycemic-index carbohydrate meals, it can lower the postprandial blood glucose in participants with prediabetes [52
Price has no significant influence on consumers’ purchasing behavior of sweeteners. Other studies showed that price is one of the most important characteristics of food purchase [36
]. It is possible that consumers assume that they only need small quantities of sweeteners, so that the price per use is low.
‘Tooth-friendly’ is the only level of dental health which is attractive for consumers. Research depicted that sugar consumption increases the risk for caries [54
]. Therefore, society associates sugar consumption with caries. Phrases such as ‘no sweets for children, otherwise there will be caries’ could be anchored in people’s minds. Sweeteners such as allulose are tooth-friendlier [55
]—a promising product characteristic to differentiate sweeteners from conventional sugar.
As the participants of this study only consisted of people who stated that they follow a healthy diet, trying to follow a healthy diet could be connected to dental health as well. Given that participants were following a healthy diet, the influence of the attribute ‘tooth-friendly’ could be lower in the German population at large.
In terms of the ‘calorie content’, only the level ‘calorie-free’ influences consumer decision-making. This is positive, as allulose, stevia, and erythritol were the sweeteners included that were nearly calorie-free. Since allulose has significantly fewer calories than regular sugar, this sweetener would help consumers in their calorie control [22
]. This therefore demonstrates the potential for allulose to support consumers in their weight management. In earlier research, fewer calories were identified as the most important attribute of sugar alternatives [25
]. Moreover, research showed that using calorie labeling promotes healthier food choices [56
]. In this sense, allulose may help consumers to follow a diet consisting of a reduced number of calories.
When consumers ranked the attribute levels of allulose, the results were different. In the ranking task, ‘no influence on blood glucose level’ achieved the highest rank. This is different from the choice experiment where the level was not significant. Furthermore, the two levels of the base product and taste, which were the most important levels in the choice experiment, were the least important in the ranking task. These differences can be based on the fact that in the ranking task, the attribute levels of allulose were queried, whereas the attribute importance contains the attributes themselves. For example, the taste of allulose was also the least-preferred level within the attribute of taste in the choice experiment. Also, the price was not included in the ranking task.
This study is the first approach to analyze consumers preferences of allulose. One limitation is that the research consists of a hypothetical purchase decision, thus future studies should involve real purchases in a supermarket and consider monetary consequences. Second, only a limited number of sweeteners are included in the survey. Future studies should include cheap talk scripts to reduce hypothetical bias.