Writing in the journal Trends in Pharmacological Sciences, the researchers from Senomyx reported that small molecules that enhance sweet taste receptor activity and sweetness perception (known as positive allosteric modulators or PAMs) could be more effective than other taste enhancers – such as existing sweeteners – at reducing calories in consumer products “without compromising on the true taste of sugar.”
“Positive allosteric modulators for the sweet taste receptor are unique and represent a significant breakthrough in the effort to control caloric intake. They could revolutionize the field of flavour development for sweetened consumer products,” said the researchers, led by Guy Servant senior director of assay development & HTS at Senomyx, USA.
“Relative to other sweet taste enhancers (i.e. the use of some non-caloric sweeteners) PAMs offer a superior approach to lowering the caloric content in food and beverages while preserving the desired taste,” they added.
They said that the success of this approach has now prompted a larger effort to identify PAMs from synthetic and natural sources, which are capable of enhancing other caloric sweeteners.
Non-caloric sweeteners
Servant and his colleagues noted that consuming foods that are high in calories and fat, while living a sedentary lifestyle “causes an energy imbalance that is at the root of various health conditions such as obesity, type II diabetes, and cardiovascular diseases, which have reached epidemic proportions in some countries.”
“As a result, more than ever before, food and beverage companies have been under pressure to cut calories and sugar to improve the overall nutritional value of their products … However, more than 100 years of research has failed to produce a zero-calorie sweetener that fully reproduces the taste of sugar,” they explained, noting that alternative sweeteners have to be used at high concentrations and can exhibit “objectionable off-tastes” in addition to problems with lingering taste profiles and limitations in intensity.
Blends of several zero-calorie sweeteners have been reported to exhibit synergistic properties when mixed with one another or with a carbohydrate sweetener, however, Servant and his team noted that only minimal sweet taste enhancement can be achieved with such blends, and apparent synergy in taste tests can only be observed at lower sweetener levels.
The authors said that the discovery of genes coding for the sweet taste receptor has been “a game changer”, that has enabled the use of high-throughput screening technologies and classical discovery approaches to identify new flavour ingredients, such as positive allosteric modulators, “which may answer the shortcomings of zero-calorie sweeteners and addressing the needs of manufacturers.”
Sweet taste modulation
Despite the relatively smaller enhancement effects provided by sweeteners in general, the authors noted that blends and new sweetener formulations remain very popular in the industry.
“They can improve the overall sweetness profile and mouth feel of food products, and sometimes even provide cost-savings to food and beverage companies … However, the beneficial effects of sweetener combinations are clearly not the result of robust synergy between each of the components but are instead due to their complementary flavour characteristics and physicochemical properties,” said Servant and his co-workers.
They said that if the goal is to enhance sweetness significantly using a low concentration of modulator and preserve the true taste of sugar, “then PAMs undoubtedly offer a better outcome than any sweetener or combination of sweeteners reported to date.”
“A unique aspect of these types of PAMs is that a separate enhancer could need to be developed for each sweetener, creating a family of sweetener-specific PAMs with high efficacy,” they added.
Source: Trends in Pharmacological Sciences
Published online ahead of print, doi: 10.1016/j.tips.2011.06.007
“The sweet taste of true synergy: positive allosteric modulation of the human sweet taste receptor”
Authors: G. Servant, C. Tachdjian, X. Li, D.S. Karanewsky