by Rachel Wilson
The global market for intense sweeteners is experiencing steady growth, as a result of the continuing consumer trend toward reduced sugar intake; in 2009, the world market for intense sweeteners was worth more than $1.27 billion.1 However from a technical point of view, intense sweetener products are undergoing a period of radical change. Having traditionally been dominated by products such as aspartame, acesulfame K and saccharin, their position may be coming under threat as the trend toward all things natural continues.
Consumers are increasingly choosing products that claim to be natural or contain all-natural ingredients and, to that end, sweeteners derived from plant sources are likely to be viewed favorably by developers, retailers and consumers alike. The key natural sweeteners from the industry’s point of view are steviol glycosides, monk fruit or luo han guo, thaumatin, glycyrrhizin and, in the future, most probably monatin.2
Stevia rebaudiana Bertoni is a member of the chrysanthemum family that grows wild in Paraguay and parts of Brazil.3 The native populations of South America have used extracts from these leaves for sweetening bitter tasting beverages for many centuries.4 Stevia leaves contain a group of seven or eight highly potent, zero-calorie sweet compounds, collectively known as steviol glycosides.
It is the Stevia rebaudiana extracts that are commonly used in commercially available stevia products with different levels of purity being available, ranging from 10-percent purity to 90-percent purity.5 The primary extract is rebaudioside A also known as rebiana or reb A and has a sweetness between 200 and 400 times that of sugar depending on concentration and application. It is suitable for use in a range of applications including low-pH carbonated beverages and dairy beverages, and it can also withstand the high temperatures reached in processes such as pasteurization or UHT. For this reason, reb A offers good potential to the bakery industry as well as applications such as dairy, soft drinks, desserts and sauces. It is most stable between pH 3 and 8, with a noticeable lessening in stability at pH less than 2. Although overall stability does decrease with temperature of storage because the breakdown products of reb A are also steviol glycosides, they are also sweet and therefore the loss in sweetness in negligible. Reb A is synergistic for sweetness with cyclamate and aspartame, and has been shown to enhance fruit flavors and salt-free seasonings.6
PureCircle was the first to successfully develop a specific sweet compound from stevia leaves, known as rebaudioside A (reb A) or rebiana. This extract has since been commercialized as Truvia® by a Cargill/Coca-Cola partnership and as PureVia® by a Pepsico and Merisant partnership.
Stevia represents one of the most dynamic sectors within the global intense sweeteners market, with sales having risen dramatically since the middle of the last decade as a result of increasing uptake within the U.S. food and drinks industry.
In 2009, global market value reached an estimated $175 million, up from just $10 million in 2005. Much of this increase has come from the United States, although it seems likely that Europe will assume increasing significance once EU approval is granted, possibly later in 2011.
Siraitia grosvenorii (also known as luo han guo) is a perennial vine of the Cucurbitaceae family and is a traditional medicinal herb cultivated principally in the Guangxi region of China.7 Although inherently sweet, the fruit itself is unsuitable for use as a sweetener without additional processing, as it has a tendency to form off-flavors by fermentation.
The sweet taste of luo han guo comes mainly from the mogrosides, a group of triterpene glycosides. The mogrosides are present in total at about 1 percent in the flesh of the fruit.8 The most abundant triterpene glycoside component is mogroside V, which is reported to be approximately 300 times sweeter than sucrose.
Through extraction processes, a powder containing up to 80-percent mixed mogrosides can be obtained, which is approximately 250 times sweeter than sugar.9 The mogrosides are inert to thermal and enzymatic degradation of digestion and, subsequently, luo han guo is a biochemically stable, non-nutritive, non-hygroscopic and non-cariogenic product.10
A number of commercially available extracts of luo han guo are available such as Mormordica (Amax Nutrasource Inc., City of Industry, CA ) and Purelo (Biovittoria, Hamilton, New Zealand). These vary in mogroside content, but are typically 20-percent to 70-percent mogroside V and 40-percent to 90-percent total terpene glycosides.
In the United States, luo han guo juice or dried concentrate has been GRAS (generally recognized as safe) since early 2010 and is generally labeled as luo han guo fruit concentrate or monk fruit concentrate.
Luo han guo is not currently a permitted sweetener in the EU, although it may be used as a natural flavor preparation at concentrations where it does not function as a sweetener. It is likely manufacturers will seek EU approval for luo han guo juice concentrate as a novel food and for the powdered product as a food additive in the next few years.