Mini review: Will artificial sweeteners discharged to the aqueous environment unintentionally “sweeten” the taste of tap water?

Abstract

Acesulfame-K, aspartame, cyclamate, neotame, saccharin, and sucralose are highly water-soluble artificial sweeteners (ASs) that are widely used in consumer products and represent a billion USD global market in 2020. In part because they are poorly removed by conventional water treatment, and acesulfame and sucralose also resist biodegradation and advanced oxidation, multiple ASs co-occur in tap water across the globe, generally at ng/L concentrations but also at µg/L concentrations. Through a review of the literature, this is the first research to integrate taste threshold concentrations with concentrations measured in drinking water to assess if consumers’ tap water will taste sweet. The taste threshold concentrations for acesulfame-K, aspartame, cyclamate, neotame, saccharin, and sucralose are 8.94, 6.59, 105.5, 0.24, and 3.49 mg/L, respectively. While reported concentration of artificial sweeteners in tap water are below their known taste thresholds for sweetness and range from ng/L to hundreds of µg/L, binary combinations of ASs can have a more intense sweetness than one artificial sweetener alone, and hard water can enhance the sweetness of acesulfame-K. Additionally, global production and consumption of ASs is expected to increase 2-5% annually; this increase, when coupled with degradation resistance and persistence, will allow AS concentrations to increase in the water cycle. Thus, in order to maintain consumer satisfaction and confidence, the drinking water industry must be vigilant concerning tastants in their tap water at levels and combinations detectable by consumers.

Keywords

• Acesulfame
• Aspartame
• Cyclamate
• Neotame
• Saccharin
• Sucralose