With sugar driven human disorders on the rise all over the world, search has been on for decades to bring out zero calorie sweeteners with unquestionable safety for long term use and having no after taste. One of the essential features of such sweeteners must be that they are as concentrated in sweetness as possible so that very small quantities can simulate sweetness of natural sugar with user friendly features. Till about a decade ago synthetic non-nutritive sweeteners were dominating the market and the safety of most of them is still under a cloud with no unanimity among safety experts. It is only recently that Stevia glycosides, extracted from the Stevia plant became an almost universally accepted natural zero calorie "sweetener" and started its commercial debut. Pushing behind all the synthetic sweeteners Stevia is at the center stage at present, with practically the entire food processing industry accepting it as an ingredient compatible with most products designed for low calories.
In spite of vast strides made in farming the plant and expanding the source of Stevia leaves from which the sweet glycosides are extracted, purified and crystallized, there still remains some problems when Stevia glycosides are used in formulating low calorie foods, most serious being the mild after taste and non-uniform taste perception in the oral cavity. While the first bite or dose consumed gives intense sweetness, subsequent ingestion gives less and less sweetness. Thus the intensity of sweetness goes down as the consumption progresses. Of course most consider this as a minor inconvenience because this is the only commercially successful non-nutritive sweetener which has established its credentials. Progress of Stevia sugar industry has been phenomenal during the last 5 years with many major producers emerging on the scene including food industry giants like Coke and Pepsi.
Practically boasting same credentials, a few next generation sweeteners are now being positioned to challenge the dominance of Stevia. Most prominent among them to hit the market is a product derived from a fruit of the herbaceous perennial vine Siraitia grosvenorii, native to southern China and northern Thailand, used traditionally by local people for imparting sweetness to their preparations. Commonly known as Monk fruit ot Buddha fruit, it is more popularly known as luo han guo in the local area. It is claimed to be a part of the traditional Chinese medicinal system with its unique property of imparting a cooling effect when consumed and was very commonly used to treat obesity and diabetes among the population there. Though the fruit juice is most commonly used as a cooling drink, its value as a source of zero calorie sweetener is attributed to a group of organic chemicals collectively called Migrosides. The juice contains fructose and glucose, both calorie yielding sugars and hence to get a product with no calorie, adequate processing is required to isolate the migrosides in pure forms.
If the reports appearing about monk fruit sweeteners are true, almost 90 percent of the sources of monk fruit is monopolized by a New Zealand-based company on whom the processors have to depend on supply of dry fruits for isolating the migrosides. Unlike Stevia glycosides, monk fruit is amenable to water extraction and it is the juice which has to be further processed to remove glucose, fructose and other calorie yielding substances to get concentrated products containing 90% plus pure migrosides. There appears to be five forms of migrosides in the fruit, distinguished by affixing numbers I to V, the sweetest being the type V, 300 times sweeter than natural sugar. In 2010 monk fruit derived sweeteners were declared as generally safe for use in foods.
One of the issues regarding the use of the word natural is whether it can be used if the raw material undergoes severe processing steps like Stevia which needs the solvent extraction process to obtain a crystalline substance with high purity. Monk fruit based sweeter preparations are made from water extracts and limited quantities available so far come from vertically integrated production system where the monopoly manufacturer supplies quality seedlings to its Chinese contract farmers who are legally bound to supply the company the entire fruit yield. it is claimed that the seedlings are the optimized result of natural plant breeding by the company through traditional practices, not resorting to genetic modification.
While most of the current interest in monk fruit is due to its sweetening ability, there are several other bio-active compounds in the fruit that could become valuable and marketed ingredients down the road. Of course there needs to be a pro-active marketing effort to make these new sweetener source acceptable to the processor and the consumer. Already there are branded products based on Monk fruit marketed by reputed companies which include 'Purefruit', 'BlueSweet', 'Fruit20', 'Fruit50', 'Nectresse' etc. Though these products are claimed to be superior to Stevia, how far the industry will agree to this claim remains to be seen. What is clear with this new avatar of sweetener is that it is going to take time, even if accepted, to fine tune its use in new food products which can be quite time consuming but probably Monk fruit will emerge as a major competitor to Stevia in the coming years.