Stevia Rebaudina News
Is there any safe and natural alternative to sugar?
by Tofazzal Islam, MD
From The Financial Express - 2006-08-26
The English word "sugar" ultimately originates from the Sanskrit word sharkara which means "sugar" or "pebble". It probably came to English by way of the French, Spanish and/or Italians who derived their word for sugar from the Arabic al sukkar. The Arabs in turn derived their word from the Persian shakar, derived from the original Sanskrit. In chemistry, sugar is known as sucrose or saccharose, a molecule composed of 12 atoms of carbon, 22 atoms of hydrogen, and 11 atoms of oxygen (C12H22O11). Humans most commonly use sucrose as their sugar of choice for altering the flavor and properties of beverages and food. Commercially-produced table sugar or sucrose comes two sugar crops, sugarcane (Saccharum spp.) and sugar beets (Beta vulgaris), in which sugar can account for 12%-20% of the plant's dry weight. Pure sucrose is the most common sweetener in the modern, industrialized world. People, and in fact most other mammals except members of the cat family, will gladly accept a food sweetened with sucrose, even if they aren't hungry.
Most of us love sweetmeats. Our palates lust for ice cream, our mouths water at the thought of varieties of sweetmeats, our parched throats yearn for soft drinks, while visions of sugar plums dance in our heads. To satisfy these craving, we consume about one hundred pounds (45 kg) of sugar per person per year. That's about 120 grams per day. Surprised? We're predisposed to seek out sugar when we can find it. After all, sugar (sucrose) is a carbohydrate. What happens to our metabolism, on all that sugar? Sugar is metabolized directly into blood sugar or glucose, which fuels our brain and muscles. The purer the source, the faster it gets into the bloodstream, bypassing much of the digestive process.
Eating sugar shoots our blood sugar levels up and triggers a spike in the hormone insulin, which is needed to prep our cells to absorb the sugar. If there are no other nutrients to sustain our blood sugar, it crashes as quickly as it rises - and we crave another hit. This is how sugar addiction begins. Moreover, sugar floods us with pleasure by stimulating the release of the neurotransmitter serotonin, and probably other mood-elevating substances. Scientists report that eating chocolate initiates a brain response similar to falling in love.
Although we get quick calorie from sucrose, it has several adverse health effects. The most common is tooth decay, in which bacteria in the mouth turn sucrose into acid that attacks tooth enamel. Sucrose has high calorie content and is also believed to cause obesity and is not ideal for our waistline. People with diabetes need to control their intake of sucrose. There have even been some controversial suggestions that excessive sugar consumption may play a role in certain degenerative diseases. It is commonly believes that eating too much sugar will cause some children to become hyperactive.
Excess sugar consumption also upsets the balance of intestinal flora in your digestive tract and can cause symptoms of intestinal distress such as bloating, cramping, and gas. Other symptoms of sugar sensitivity are headaches, insomnia, aggression, panic attacks, irritability, mood swings, and depression. New studies in accelerated aging link elevated sugar intake with a process called glycosylation: proteins in our bodies morph into AGE's, or advanced glycosylation end-products, a kind of metabolic debris that collects in our organ, joint, and skin tissues. It is stated that sugar should not account for more than 10% of a healthy diet. Therefore, the wave is coming because "low-sugar" or "sugar-free" is the latest fad - a welcome trend, given the health hazards of all the sugar in the average diet.
Many no-calorie synthetic alternatives of sugar popularly known as artificial sweeteners have been discovered. The food and beverage industry is increasingly replacing sugar or corn syrup with artificial sweeteners in a range of products traditionally containing sugar. In the UK, for instance, it is now almost impossible to find any non-cola soft drinks in supermarkets which are not sweetened with artificial sweeteners, and even things like pickled beetroots and gherkins are increasingly artificially sweetened. The four primary compounds widely used as sugar substitutes in the United States and many other countries are saccharin, aspartame, sucralose, and cyclamate. Howevers, there is ongoing controversy over the supposed health risks of the artificial sweeteners such as saccharin and aspartame. Some studies have shown that they cause brain tumors as well as lymphatic cancers in laboratory animals. Multiple scientific studies have demonstrated health risks of saccharin to humans.
For various adverse effects of artificial sweeteners and sugar (sucrose), the search for natural plant sweeteners has been intensified in recent years. Meanwhile, several compounds are discovered and some of them being developed for commercial application. The fact that certain plant molecules other than carbohydrate have intense sweetness has been known for some time.
One of the best known natural sweet compounds is stevioside, a diterpenoid glycoside which occurs in the leaves of a plant named Stevia rebaudiana belonging to the Compositae family. It is a remarkable South American plant that has become widely used in certain parts of the world as a natural sweetening agent and dietary supplement. Purified extracts of Stevia have been used as sweeteners and flavour enhancers in the food industry in Japan for over a quarter of a century, and have been found to be up to 300 times sweeter than sucrose. So a small portion of Stevia will sweeten even a strong cup of tea. Stevia has been used in many other countries for over 400 years without any side-effect.
The advantages of sweet stevia leaves and stevioside are manifold. These are: non-toxic, non-calorific, heat stable, not fermentative, flavour enhancing, 100 % natural, no aftertaste or bitterness, non-carcinogenic, non-addictive sweetener for children, and an intense sweetener compared to sucrose. Due to non-calorific property, it is absolutely safe for diabetics, phenylketonurie (PKU) patients and slimming people. Stevia can be used for anything you might use sugar in, including baking. For men and women who want to move through their cravings for sugar without artificial chemicals, Stevia is a great option.
Stevia is recently introduced in Bangladesh, however, it may take time to acclimatize this plant for commercial use as a natural sweetener. As the content of stevioside in the leaves of Stevia is largely varies between 4.0 % and 20 % of the dry weight of the leaves depending on the cultivar and on growth conditions, extensive research activities are needed to quantify stevioside content in leaves and find out suitable cultivation techniques for commercial production of stevia in different soils of Bangladesh.
Several plant-derived compounds of the terpenoid and phenolic types have commercial use as sweeteners. Let us discuss some of these exciting known natural products. Hernandulcin, a natural sweet compound, named after the Spanish physician Francisco Hernández, since in the 16th century he drew attention to this same remarkably sweet plant, which was known to the Aztecs under the Nahuatl name "Tzonpelic xihuitl" ("sweet herb"). It has been found up to 1000 times sweeter than sucrose. Gaudichaudioside A isolated from an herb, Baccharis gaudichaudiana DC. (Compositae) is sweeter than 2.0 % sucrose by 55 times. Periandrin V (triterpene glycoside) isolated from the rhizomes of a plant, Periandra dulcis L (Brazilian licorice), is rated as about 90 -100 times sweeter than sucrose.
Four glycosidic compounds, abrusosides A-D isolated from the leaves of Abrus precatorius L. (Leguminosae) were rated 30, 100, 50, and 75 times sweeter than sucrose, although it was found that these glycosides elicit a delayed sweetness response. The leaves of a Chinese herb, Pterocarya paliurus are known as "sweet leaf tree" are used locally to sweeten foods in cooking. Two new sweet-tasting 3,4-seco -dammarane glycosides, which were accorded the trivial names, pterocaryosides A and B, respectively were discovered from this plant. The ammonium salts of pterocaryosides A and B were rated 50 and 100 times, respectively, than the sweetness intensity of 2.0 % w/v sucrose.
Soft drinks incorporating extract of the fruits of Siraitia grosvenorii (Cucurbitaceae) containing sweet cucurbitane-type triterpene glycosides such as mogroside V are now on the market. It is surprising to note here that some plant molecules have shown up to 5,000-fold sweeter than the sucrose. Some other powerful sweeteners from natural sources and there sweetness relative to sucrose (in perenthesis) are as follows: sorbitol (0.6 ×), glucose (0.7 ×), xylitol (1.0 ×), fructose (1.3 ×), cyclamate (30 ×), glycyrrhizin (50 ×), mabinlin protein (100 ×), brazzein protein (2000 ×), aspartame (200 ×), acesulfame K (200 ×), saccharin (300 ×), naringenin dihydrochalcone (500 ×), curculin protein (550 ×), sucralose (650 ×), neohesperidin dihydrochalcone (1000 ×), brazzein protein (2000 ×), monellin protein (3000 ×), serendip protein (3000 ×), thaumatin protein (5000 ×), pentadin protein (5000 ×) and so on. The discovery of these natural alternatives of sugar offer tremendous potential for commercial use as safe sweetener and solve the current crisis of health hazards of sugar.
The sugar or sucrose is the most popular sweetener in the world. However, for adverse health effects of sugar and artificial sweeteners, the interest and search for no calorie natural sweeteners has been intensified in recent years. Several low or no calorie natural sweeteners from plant origins such as stevioside, glycyrrhizin, neohesperidin dihydrochalcone, thaumatin protein etc., have been discovered and some of them are now being developed for commercial application. The diabetic patients and any healthy sweet lovers may satisfy their emotional incentives by natural no calorie sweeteners such as stevia or stevioside as the safe alternatives of sugar. As stevia is introduced in Bangladesh, research efforts are needed in developing appropriate techniques for commercial cultivation and utilization of this magic plant as a safe alternative of sucrose.
[The writer is Associate Professor (Ecological Chemistry, School of Agriculture and Rural Development, Bangladesh Open University, Gazipur-1705, Bangladesh. E-mail: email@example.com, telephone - 01715107419)]