The soil water limitation is a relevant abiotic stress that affects the plants life. In this respect, adoption of an efficient strategy may improve the plant growth during this stress. The present study was conducted in order to find the likely useful effect of the humic acid (HA) on stevia (Stevia rebaudiana) in a pot trial, especially under drought stress condition. Therefore, five levels of humic acid (0, 1, 1. 5, 2, and 2. 5 mg. kg-1 soil) were applied to the soil planted with Stevia seedling under normal (well-watered) and drought stress condition (resulted from 10-day irrigation intervals), based on a factorial experiment with three replications. Drought stress significantly reduced the stevia leaf production and steviol glycosides (SVglys) content and compositions. Stevioside (Stev) and Rebaudioside A (Reb A) contents significantly decreased under drought stress and all concentrations of HA. On the other hand, HA (in concentrations more than 1. 5 mg. kg-1 soil) strongly increased leaf production in stevia and resulted in a significant increase in SVglys yield (44% in comparison with no HA). Results clearly demonstrated that although HA showed an inhibitory effect for SVglys content in stevia leaf, it can increase the SVglys yield through a remarkable increase in leaf growth in stevia, especially under drought stress condition.

Introduction  Sesame paste is a product that is obtained by mixing Ardeh obtained from peeling of Sesame seeds with sugar or other sweeteners and flavorants such as cardamom and vanilla. Each 100 grams of this nutritious product contains 558 kcal and providing 17% of the daily calcium need, 100% for iron and 26% for protein. Sesame cream /Ardeh cream provides 478 kcal per 100 grams. Ardeh cream is also a good alternative to chocolates with artificial colors, so it is a very good choice in cases of hypoglycemia, such as before the exam session of students or during heavy excersize such as mountaineering. Sugar substitutes are compounds that, like sugars, are used to sweeten foods, except that they are not digested without the need for metabolized insulin, or are digested sparingly and therefore have little caloric value. The diet products are usually based on reducing calorie intake, which today, the growing interest of people in eating healthy diet has led to an increase in their desire to consume low-calorie products. Patients with diseases caused by sugar consumption such as diabetes, hypertension and hyperlipidemia, osteoporosis, obesity, etc. tend to use artificial sweeteners such as saccharin, aspartame, cyclamate and acesulfame. Materials and Methods  Hydrogenated oil, Skim milk powder, Whey powder, Soy lecithin, Potassium dichromate, Ethanol, Ardeh , Erythritol, Isomalt Powder, Ribodioside a, Sugar  Stable micro histometer systems, Ballmer, Memmert model digital scale, Autoclave, Oven, N Hexane, Desiccator, Soxhlet device, 500 cc balloon, Peptone water, Dichlorine-Rose Bengal Chloramphenicol Agar (DG18), coax reagent, EC broth culture medium, lauryl sulfate culture medium, pH meter with measuring accuracy of 0.1%, 0.1 N sulfuric acid solution, Potassium sulfate, dioxide Selenium, boric acid solution, crystallized copper sulfate, aluminum plate were used in this study . First, to prepare a control sample, raw materials such as flour, oil and sugar were added to the mixer and mixed together, then the rest of the ingredients were added and mixed inside the machine to make the cream uniform and homogeneous. Then it was transferred to the filter and packed in the desired containers. Sugar substitutes were used for the rest of the samples. Results and Discussion   The prevalence of obesity and diabetes has increased dramatically in recent years, forcing consumers to look for low-calorie sweeteners. Replacing low-calorie sweeteners with sucrose results in low-calorie,  and healthy foods. The aim of this study was to present a new formulation using isomalt, ribadioside a, erythritol as sucrose substituents and to investigate its effect on chemical, physical and sensory properties of substituted samples compared to the control sample. The use of sucrose substituents was effective in improving some physicochemical properties of Ardeh so that the moisture content of the substituted samples increased. The results of histological examination also showed that the replaced samples had softer tissue than the control sample, which was due to the weakening of tissue stability by sucrose substitutes. The results of sensory properties based on aroma, taste, odor and texture also showed that sample 2 with the formula 25% sucrose, 6.25% isomalt, 0.003 ribodiozide obtained the highest score in terms of overall acceptance. The reason for the decrease in the general acceptance of the samples replaced with complete elimination of sucrose is the lack of regulation of the desired sweetness by these alternatives. The results of microbial analysis of samples also showed that sugar substitutes have no effect on the microbial properties of Ardeh. According to the obtained results, sample 2 with 25% sucrose, 6.25% isomalt, 0.003% ribodioside a is the best combination and a healthy and low calorie snack.

To study the effect of foliar application of proline and salicylic acid on steviol glycosides and phenolic of Stevia, an experiment was conducted based on a completely randomized block design in a factorial arrangement with three replications in the University of Zanjan. Foliar application of proline in three levels (0, 1, 2 mM) as well as salicylic acid (0, 0. 3, 0. 6 mM) were applied after establishment of transplants in the field three times with 10 days intervals. Results showed that salicylic acid and proline applications significantly influenced steviol glycosides, phenol and flavonoid. The treatment with salicylic acid had positive effects on all steviol glycosides, phenol and flavonoid, but proline only enhanced contents of glycosides stevioside, rebaudioside A, phenol and flavonoid. The highest average steviol glycosides stevioside (60. 32 mg/g dw), rebaudioside A (24. 14 mg/g dw) and total phenol (19. 94 mg/g dw) were recorded in 1 mM proline in combination with 0. 6 mM salicylic acid. The highest average flavonoid (10. 02 mg/g dw) in 0. 6 mM salicylic acid, and lowest average steviol glycosides and phenolic contents were observed in the control. Collectively, the results showed that application of proline and salicylic acid significantly improved production of active substances in Stevia rebaudiana.

The aim of this research was to produce functional cacao milk by the use of sugar substitutes that its sensory characteristics are similar to cacao milk containing sugar. Rebaudioside A, inulin, oligofructose and isomalt have been used as sugar substitutes in functional cacao milk. After producing 36 functional cacao milk samples with different formulations, treatment T1 (containing 65% rebaudioside A, 5%inulin, 10% oligofructose, 20%isomalt) and treatment T2 (containing 65% rebaudioside A, 10%inulin, 10%oligofructose, 15% isomalt were chosen. The other treatments were not accepted due to the bitter after-taste. The results of physicochemicall tests indicated that viscosity and pH of T1 and T2 samples were higher in comparison with control sample. The viscosity of treatments increased significantly during storage time (p<0.05). The results of pH tests revealed that pH decreased during storage time (p<0.05). There was no significant difference between acidity of samples in 1st and 3rd days (p>0.05). Meanwhiles, acidity of treatments increased significantly during storage time (p<0.05). The results of overall acceptability assessment showed that there was no significant difference between T1 and control treatments, while there was a significant difference between T2 and control samples (p<0.05). Also, treatment T1 gained more score in comparison with treatment T2; so, it can be concluded that treatment T1 was very similar to control treatment and it could be used in producing functional cacao milk.

Background: Rebaudioside A is one of the major diterpene glycosides found in Stevia had been reported to possess anti-hyperlipidemic effects. In this study, we explore the potential cholesterol-regulating mechanisms of Rebaudioside A in the human hepatoma (HepG2) cell line in comparison with simvastatin. Methods: Cells were incubated with Rebaudioside A at several concentrations (0-10 μ, M) to determine the cytotoxicity by the MTT assay. Cells were treated with selected dosage (1 and 5 μ, M) in further experiments. Total cellular lipid was extracted by Bligh and Dyer method and subjected to quantitative colorimetric assay. To illustrate the effect of Rebaudioside A on cellular lipid droplets and low-density lipoprotein receptors, treated cells were subjected to immunofluorescence microscopy. Finally, we investigated the expression of experimental gene patterns of cells in response to treatment. Results: In this study, cytotoxicity of Rebaudioside A was determined at 27. 72 μ, M. Treatment of cells with a higher concentration of Rebaudioside A promotes better hepatocellular cholesterol internalization and ameliorates cholesterol-regulating genes such as HMGCR, LDLR, and ACAT2. Conclusions: In conclusion, our data demonstrated that Rebaudioside A is capable to regulate cholesterol levels in HepG2 cells. Hence, we proposed that Rebaudioside A offers a potential alternative to statins for atherosclerosis therapy.

Stevia rebaudiana is an important medicinal plant that is used by people with diabetes because of its steviol glycosides such as stevioside and rebaudioside A. Considering the limitation of seed production in this plant and the time-consuming nature of its propagation by stem cuttings, the use of a hairy root culture can be a suitable strategy for the production of these compounds. In this study, after the production of hairy roots by Agrobacterium rhizogenes strain ATCC15834 and their proliferation, different concentrations of methyl jasmonate (0, 50, 100, 150, and 200 µM) and salicylic acid (0, 30, 60, 90, and 120 mg/L) were applied and sampling was done at different times (24, 48, 72, and 96 h). The use of 100 μM methyl jasmonate for 48 h resulted in the accumulation of 47.31 mg/g DW, the production of 134.30 mg/L stevioside, the accumulation of 45.11 mg/g DW, and the production of 128.41 mg/L rebaudioside A and the use of 200 μM caused the accumulation of 45.56 mg/g DW and production of 120.47 mg/L rebaudioside A. While, among the different concentrations of salicylic acid, only the use of 90 mg/L for 72 h increased the accumulation of rebaudioside A (68.36 mg/g DW), and the other concentrations had a negative effect on the accumulation and production of stevioside and rebaudioside A. In conclusion, these findings showed that methyl jasmonate and salicylic acid can inhibit the growth of hairy roots and instead enhance the accumulation and production of stevioside and rebaudioside A.

In order to investigate the effect of harvesting time (17 August and 17 September) and planting space (20, 25, 30 and 35 × 50 cm) on growth criteria, quantitative and qualitative yield of Stevia rebaudiana Bertoni, a factorial experiment based on randomized complete block design with three replications was carried out in Research Station of Department of Horticultural Science and Landscape Engineering, University of Tehran during years of 2013-2014. Based on results, planting space significantly affected the most measured traits except plant height, leaf to stem ratio and chlorophyll content. By decreasing of planting space from 35×50 to 20×50 cm, fresh and dry weight of the aerial part and leaf and yield of Stevioside and Rebaudioside A were increased. Also, harvesting time significantly affected the measured traits except chlorophyll content in which the highest plant height and diameter, fresh and dry weight of the aerial part and yield of Stevioside and Rebaudioside A were obtained at 17 September. Harvesting at 17 August caused the highest leaf to stem ratio. The interaction effect of planting space and harvesting time significantly affected leaf dry weight in which the highest leaf dry weight obtained by the planting space 20×50 cm and 25×50 cm at 17 September. There was no significant effect on chlorophyll content. In general, based on these results, planting space of 20 and 25 × 50 cm and harvesting time at 17 September compared to other treatments pronounced better for cultivation of Stevia in studied area of Karaj.

Introduction: Stevia might be used as a new source of sweetener but without containing sugar and is a suitable alternative to sucrose. It is important in health care and solving restrictions of sugar consumption by diabetics. Therefore the aim of this study is to evaluate the effect of arbuscular mycorrhizal fungi and rhizobium bacteria co-symbiosis on steviol glycosides content in herbal plant of stevia. Materials and Methods: The effect of mycorrhizal fungi in three and rhizobium bacteria in five concentrations were conducted on stevia through factorial experiment in randomized complete block design with three replications in research greenhouse of the faculty of Agriculture and Food at Tarbiat Modares University. Results: The results revealed that the effect of mycorrhizal fungi, rhizobium bacteria and its interactions were significant on all characteristics. The highest percent of stevioside and rebaudioside A glycosides was gained in b0f25 and b100f50 treatments, respectively. Conclusion: It is concluded that co-symbiosis of mycorrhizal fungi and rhizobium bacteria with stevia could efficiently improve the economical yield.

Kefir ice cream is a fermented dairy dessert made using kefir in the formulation of ice cream. The objective of this study was to produce kefir ice cream by use of low-calorie sweeteners including Rebaudioside A and isomalt in place of sucrose. Treatments A (control, only sugar), B (4 % isomalt and 10 % Rebaudioside A), C (6% isomalt and 20% Rebaudioside A), D (8% isomalt and 30% Rebaudioside A) and E (10% isomalt and 40% Rebaudioside A) were evaluated for physicochemical and sensory properties as well as probiotic bacteria count on 1, 30, 60 and 90 d. The results showed that by adding stevia and isomalt, acidity, viscosity and probiotic bacteria count significantly increased while pH and over run significantly decreased (P< 0. 05). During storage, the viability of probiotic bacteria, pH and over run significantly decreased while acidity and viscosity significantly increased (P<0. 05). Scores of flavor and total acceptance for treatments D and E were lower than those of other samples. Treatment C (6% isomalt and 20% Rebaudioside A) was selected as the superior one because in addition to having more desirable physicochemical characteristics compared to control sample, it showed no significant difference from control in sensory total acceptance and its probiotic bacteria count was higher than the limit recommended by International Dariy Federation (106 CFU/g).