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Využití stévie sladké (Stevia rebaudiana, Bertoni) ve výživě člověka
KÜFFNEROVÁ, Nela
The Bachelor's thesis is focused on the use of Stevia rebaudiana (Stevia rebaudiana var. Bertoni) in human nutrition as an alternative sweetener with many positive side effects. Stevia rebaudiana var. Bertoni, also known as honey leaves or Stevia sugar, belongs to the star family (Asteraceae). Its area of origin is the territory of Paraguay in South America and it was first described in 1887 by botanist, Moises Santiago Bertoni. Stevia belongs to the perennial plant group; it grows to one meter in height, the leaves are dark green, densely dotted with fine hairs. The flowers are whitish. The roots grow just under the soil surface, due to the shallow root system. The overall plant appearance depends mainly on the space for growth and nutrient content in the soil. When planting, it is necessary to observe the sowing periods, which range between February and March. It is also important to maintain a constant temperature during germination, which should not drop below 10°C. The Asteraceae family includes 154 species of Stevia. Stevia rebaudiana var. Bertoni is the only one to be characterised by a sweet taste and is therefore the subject of research in the field of nutrition and food. The diterpene sterol glycosides present in it are responsible for its sweetness. The greatest proportion up to 95 % of sterol glycosides is composed of Steviosides and Rebaudiosides A, B, C, D, E, F. Current society is searching for new, alternative methods of sugar replenishment, characterised by a high energy value. The excessive consumption of beet sugar is one of the causes of the high increase of lifestyle diseases, such as diabetes or obesity. The possibility of using the malted potential of Stevia appears to be a suitable alternative. Many studies have been carried out to date. They have investigated the effect of Stevia on human health and its safety for food industry usage. Studies' conclusions demonstrate very good effects of Stevia extracts in the treatment or prevention of certain diseases. For people suffering from Type II Diabetes, the use of Stevia as a sweetener is totally safe, without any negative side effects. Due to the zero energy value, it is suitable for people suffering from obesity, when it is necessary to reduce the caloric intake of food. Investigations have been were carried out in connection with the possible carcinogenicity, mutagenicity, dental caries or potential impact on the fertility. Stevia extracts have been authorised in the EU since 2010, when the European Food Safety Authority (EFSA) issued an opinion on the safety of sterol glycosides, extracted from the plant of Stevia rebaudiana var. Bertoni. The daily acceptable dose of 4 mg/kg body weight was also determined.
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