Publication: Influencia de factores ambientales y hormonales sobre la concentración de glicósidos de esteviol en Stevia rebaudiana (Bertoni)Bert.
Authors
Guardiola González, Ascensión
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Facultad de Biología
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Río Conesa, José Antonio del
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DOI
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info:eu-repo/semantics/bachelorThesis
Description
Abstract
La problemática arraigada a los edulcorantes ha llevado al estudio de nuevos tipos de aditivos alimentarios. Entre ellas, los glicósidos de esteviol se están utilizando como edulcorantes naturales acalóricos que presenta entre 300-400 veces mayor dulzor que la sacarosa. Los glicósidos de esteviol son metabolitos secundarios con características saciantes. Se encuentran en diferentes especies vegetales, sin embargo, la más utilizada para su obtención e investigación es Stevia rebaudiana Bertoni (Bert.). Los glicósidos de esteviol son diterpetos procedentes de la ruta del mevalonato, cuya biosíntesis presenta una parte en común con la biosíntesis del ácido giberélico y otra parte en la que se produce la glicosilación de esteviol. Sin embargo, la concentración de glicósidos de esteviol en las hojas no es la misma debido al perfil genotípico de la planta, el estado de desarrollo, la ubicación de las hojas, la variación ambiental y hormonal o el método de extracción, purificación y cuantificación. Dentro de las variaciones ambientales que provocan un cambio en la concentración de glicósidos de esteviol nos encontramos factores como la sequía, la temperatura, salinidad, la radiación, toxicidad por metales o una deficiencia de nutrientes. Sin embargo, una salinidad elevada no favorece la expresión de las enzimas implicadas en la biosíntesis de glicósidos de esteviol. En cuanto a las variaciones hormonales que repercuten sobre la concentración de glicósidos de esteviol nos podemos encontrar con hormonas como auxina, giberelina, citoquininas, metil-jasmonato, ácido salicílico y hormonas inhibidoras de la biosíntesis de giberelinas, sin embargo, los tratamientos con metil-jasmonato no favorece el aumento de la concentración de glicósidos de esteviol. Además, cabe destacar, que diferentes factores como el aumento de la temperatura, Na2CO3, polietilenglicol, nitrógeno, giberelinas y ácido salicílico favorece la síntesis de glicósidos de esteviol, mientras que los tratamientos con ZnO, CuO, prolina, KH2PO4, citoquininas y auxinas estimula la síntesis de rebaudiósido A.
The problem rooted in sweeteners has led to the study of new types of food additives. Among them, steviol glycosides are being used as natural a caloric sweetener that present between 300-400 times greater sweetness than sucrose. Steviol glycosides are secondary metabolites with satiating characteristics. They are found in different plant species, however, the most commonly used for obtaining and researching them is Stevia rebaudiana Bertoni (Bert.). Steviol glycosides are diterpenes from the mevalonate pathway, whose biosynthesis has a part in common with the biosynthesis of gibberellic acid and another part in which the glycosylation of steviol is produced. However, the concentration of steviol glycosides in the leaves is not the same due to the genotypic profile of the plant, the stage of development, the location of the leaves, the environmental and hormonal variation or the method of extraction, purification and quantification. Among the environmental variations that cause a change in the concentration of steviol glycosides we can find factors such as drought, temperature, salinity, radiation, metal toxicity or a deficiency of nutrients. However, a high salinity does not favor the expression of the enzymes involved in the biosynthesis of steviol glycosides. As for the hormonal variations that affect the concentration of steviol glycosides, we can find hormones such as auxin, gibberellin, cytokinins, methyljasmonate, salicylic acid and hormones inhibitors of gibberellin biosynthesis, however, the treatments with methyl- Jasmonate does not favor the increase in the concentration of steviol glycosides. In addition, it should be noted that different factors such as increased temperature, Na2CO3, polyethylene glycol, nitrogen, gibberellins and salicylic acid support the synthesis of steviol glycosides, while treatments with ZnO, CuO, proline, KH2PO4, cytokinins and auxins stimulate the synthesis of rebaudioside A.
The problem rooted in sweeteners has led to the study of new types of food additives. Among them, steviol glycosides are being used as natural a caloric sweetener that present between 300-400 times greater sweetness than sucrose. Steviol glycosides are secondary metabolites with satiating characteristics. They are found in different plant species, however, the most commonly used for obtaining and researching them is Stevia rebaudiana Bertoni (Bert.). Steviol glycosides are diterpenes from the mevalonate pathway, whose biosynthesis has a part in common with the biosynthesis of gibberellic acid and another part in which the glycosylation of steviol is produced. However, the concentration of steviol glycosides in the leaves is not the same due to the genotypic profile of the plant, the stage of development, the location of the leaves, the environmental and hormonal variation or the method of extraction, purification and quantification. Among the environmental variations that cause a change in the concentration of steviol glycosides we can find factors such as drought, temperature, salinity, radiation, metal toxicity or a deficiency of nutrients. However, a high salinity does not favor the expression of the enzymes involved in the biosynthesis of steviol glycosides. As for the hormonal variations that affect the concentration of steviol glycosides, we can find hormones such as auxin, gibberellin, cytokinins, methyljasmonate, salicylic acid and hormones inhibitors of gibberellin biosynthesis, however, the treatments with methyl- Jasmonate does not favor the increase in the concentration of steviol glycosides. In addition, it should be noted that different factors such as increased temperature, Na2CO3, polyethylene glycol, nitrogen, gibberellins and salicylic acid support the synthesis of steviol glycosides, while treatments with ZnO, CuO, proline, KH2PO4, cytokinins and auxins stimulate the synthesis of rebaudioside A.
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