Natural Low-calorie Sweetener Research Articles

Insight into the interaction and binding mechanism of a natural nonnutritive sweetener mogroside V with soybean protein isolates based on multi-spectroscopic techniques and computational simulations

As a natural low-calorie sweetener, Mogroside V (Mog-V) has gradually become one of the alternatives to sucrose with superior health attributes. However, Mog-V will bring unpleasant aftertastes when exceeding a threshold concentration. To investigate the possibility of soy protein isolates (SPIs), namely β-conglycinin (7S), and glycinin (11S) as flavor-improving agents of Mog-V, the binding mechanism between Mog-V and SPIs was explored through multi-spectroscopy, particle size, zeta potential, and computational simulation. The results of the multi-spectroscopic experiments indicated that Mog-V enhanced the fluorescence of 7S/11S protein in a static mode. The binding affinity of 7S-Mog-V was greater compared with 11S-Mog-V. Particle size and zeta potential analysis revealed that the interaction could promote aggregation of 7S/11S protein with different stability. Furthermore, computational simulations further confirmed that Mog-V could interact with the 7S/11S protein in different ways. This research provides a theoretical foundation for the development and application of SPI to improve the flavor of Mog-V, opening a new avenue for further expanding the market demand for Mog-V.

Low-Dose Stevia (Rebaudioside A) Consumption Perturbs Gut Microbiota and the Mesolimbic Dopamine Reward System.

Stevia is a natural low-calorie sweetener that is growing in popularity in food and beverage products. Despite its widespread use, little is understood of its impact on the gut microbiota, an important environmental factor that can mediate metabolism and subsequent obesity and disease risk. Furthermore, given previous reports of dysbiosis with some artificial low-calorie sweeteners, we wanted to understand whether prebiotic consumption could rescue potential stevia-mediated changes in gut microbiota. Three-week old male Sprague–Dawley rats were randomized to consume: (1) Water (CTR); (2) Rebaudioside A (STV); (3) prebiotic (PRE); (4) Rebaudioside A + prebiotic (SP) (n = 8/group) for 9 weeks. Rebaudioside was added to drinking water and prebiotic oligofructose-enriched inulin added to control diet (10%). Body weight and feces were collected weekly and food and fluid intake biweekly. Oral glucose and insulin tolerance tests, gut permeability tests, dual X-ray absorptiometry, and tissue harvest were performed at age 12 weeks. Rebaudioside A consumption alone did not alter weight gain or glucose tolerance compared to CTR. Rebaudioside A did, however, alter gut microbiota composition and reduce nucleus accumbens tyrosine hydroxylase and dopamine transporter mRNA levels compared to CTR. Prebiotic animals, alone or with Rebaudioside A, had reduced fat mass, food intake, and gut permeability and cecal SCFA concentration. Adding Rebaudioside A did not interfere with the benefits of the prebiotic except for a significant reduction in cecal weight. Long-term low-dose Rebaudioside A consumption had little effect on glucose metabolism and weight gain; however, its impact on gut microbial taxa should be further examined in populations exhibiting dysbiosis such as obesity.

Potential antagonistic phylloplane fungi from Stevia rebaudiana Bert. as bio-control of aerial blight disease caused by Rhizoctonia solani

Stevia rebaudiana Bert. is, a natural low calorie sweetener, subjected to isolate potential fungal antagonist. Phylloplane fungi were used as biocontrol of aerial blight disease caused by Rhizoctonia solani. A survey of fungal pathogens of S. rebaudiana was conducted in three different regions of Uttarakhand state. R. solani was the causative agent of aerial blight on Stevia leaves and found pathogenic to the weed. The morphological study and antagonistic tests were executed in this study. Twenty-two fungal species were isolated and tested as antagonist against R. solani. Trichoderma hamatum, Aspergillus sp., Curvularia lunata and Emericella nidulans antagonised R. solani by overgrowing on it. Metabolites produced by thirteen fungal species affected the pathogen by antibiosis. This finding showed that T. hamatum and Aspergillus sp. exhibited the highest antagonist effects on R. solani and could be helpful in the management of aerial blight disease of Stevia.

Chemistry and analytical techniques for ent-kaurene-glycosides of Stevia rebaudiana Bertoni - A review

The Stevia genus encompasses about 200 herbs and shrubs species. Stevia rebaudiana, one of the members has gained commercial importance as a natural low calorie sweetener, due to the presence of high con-centration of stevioside and rebaudioside - A (25% to 45% of stevioside content) in the leaves. The major processes involved in the production and quantification of steviol glycosides are extraction, purification and estimation. Various extraction methods have been used for extraction of steviol glycosides in the world. The extraction methods of steviol glycosides mostly differed at the stage of clarification of extracts. The present study is an attempt to summarize the scattered literature and reports on a single podium. Moreover, it also depicts up to date literature regarding numerous extraction, purification and quantitative estimation methods for steviol glycosides

Morphological and anatomical study of stevia leaves (Stevia rebaudiana (Bertoni) Hemsley)

Topicality . Stevia rebaudiana (Bertoni) Hemsley is a perennial plant that originates from Paraguay and southern Brazil. In Ukraine the plant is cultivated. Stevia is a natural low-calorie sweetener with a wide range of health care properties. It is used as a hypoglycemic, anticarcinogenic, antioxidant, bactericidal, antiviral, anti-inflammatory and antihypertensive agent. Aim . The aim of our study was to analyse the morphological and anatomical structure of Stevia rebaudiana (Bertoni) Hemsley leaves. Materials and methods . Stevia leaves were harvested on the research area of the cultural flora department of M. M. Gryshko National botanical garden NAS of Ukraine during the mass blossoming of plants in 2016. Specimens production was carried out by conventional methods. We used a microscope MC 10 (glasses X5, X10, 15, lenses X10, X40). Photomicrographs were made with a camera Samsung PL50. We analysed the agents of epidermis from the surface (edge, the middle of the upper and lower sides of the leaf blade, its cross cut), cross cuts of a petiole. Results and discussion . Morphological structure : leaves are opposite, short, without stipules, lanceolate or ovoid, with a serrated edge, gently wrapped down. Reticulated nervation. The leaf is more pubescent on the lower side, over the nerves and along the edge of the leaf blade. The leaves are more pubescent on the top of the plant. The colour of the leaf blade on top is green and on bottom is a little lighter. The taste is sweet, spicy with a slightly bitter aftertaste. The smell is pleasant, fragrant. Microscopic analysis: epidermis of a leaf blade is covered with multicellular hairs and glands. The cells of the upper epidermis are with thin, sinuous walls, few stomata, anisocytic type. Many simple hairs of different thickness and length. The cells of the lower epidermis have sinuous walls and stroke cuticle, many stomata. The anatomical structure of the blade is amfistomatic, dorsiventral. On cross cuts the petiole is oval, with a small notch on the adaxial side and with small side wings. The main area of the petiole takes parenchyma. The leading system of the petiole consists of five rounded vascular bundles: one central, two lateral of about the same size and two small, located closer to the wings of the petiole. Bundles are collateral, with a small area of the phloem, small, without the mechanical elements. The epidermis of a petiole is with hairs and glands. Conclusions . The main morphological and anatomical characteristics of Stevia rebaudiana (Bertoni) Hemsley leaves were found on the basis of macro and microscopic analysis, that were used during the drafting of the quality control methods project on a new herb “Stevia leaves”.

Quality attributes of reduced-sugar Iranian traditional sweet bread containing stevioside

The objective of this study was to investigate the suitability of stevioside, a natural low-calorie sweetener, as a replacement for sucrose in Iranian sweet bread. A sucrose containing sweet bread recipe was prepared as the control. Sucrose was replaced with stevioside at 0, 50 and 100% levels. The baked breads were evaluated for physical, chemical, textural and sensory analyses. Results indicated that the stevioside replacement had no significant effects (P < 0.05) on ash, fat and protein contents of sweet breads but the pH and moisture content increased significantly. Moreover L* and b* values of final product were increased whilst a* value was decreased. For 50% sucrose replacement, the appearance, colour, texture, flavour and overall acceptability were comparable to those of the control (sample with 0% stevioside) with an about 11% calorie markdown. This study provides information on how sugar substitution by stevioside affects the properties of the Iranian traditional sweet bread quality. Data reported on the physical, chemical, textural and sensory properties of sweet bread are important in the development of new low-calorie products.

Confectionery gels: Effects of low calorie sweeteners on the rheological properties and microstructure of fish gelatin

Low calorie sweeteners, such as xylitol and stevia, are being used for confectionery gels. Xylitol is digested using the human’s glucose pathway and stevia is a natural low calorie sweetener. However, the microstructure and rheological properties of fish gelatin (FG) confectionery gels with these sweeteners has not been studied. Therefore, the effects of xylitol or stevia at 0, 1, 3, 5, 10 and 20% on the rheological properties and microstructure of FG (6.67% w/w) were studied. The addition of xylitol at low concentrations (i.e., 3–5%) increased the gel strength. However, the gel strength decreased upon further addition of xylitol, likely due to the xylitol preventing gel network formation. The gel strength decreased as stevia increased, which might be attributed to an antagonism that prevents fish gelatin from forming three dimensional network structures. Fourier transform infrared (FTIR) spectroscopy showed that the overall intensities of Amides A, B, I, II, III and the Fingerprint region increased with increasing concentrations of xylitol and stevia, suggesting decreased molecular order. Xylitol had more pronounced effects than stevia, which probably was related to its greater solubility and number of OH groups.

High‐level extracellular expression of inulin fructotransferase in Pichia pastoris for DFA III production

Inulin fructotransferase (IFTase) catalyzes inulin conversion to difructose anhydride (DFA III), which is a natural low-calorie sweetener. Although heterologous expression of IFTase was achieved in Escherichia coli, the extracellular enzyme activity was very low, which limited the commercialization of IFTase. Active IFTase of about 43 kDa molecular mass of subunit was extracellularly expressed by Pichia pastoris and was greatly regulated by the IFTase gene copy number integrated into the P. pastoris genome and by the methanol concentration in the induction phase. Under optimized culture conditions, multicopy P. pastoris exhibited a maximum extracellular IFTase activity of 105.4 U mL(-1) in a 5 L fermenter, which was 8.9-fold the activity in shake flasks and 5.3-fold that obtained from wild-type strain. IFTase was expressed in a eukaryotic P. pastoris system for the first time and achieved high-level extracellular expression using a high-cell-density fed-batch cultivation strategy. This demonstrated that P. pastoris was a good candidate for potential DFA III production as a novel IFTase expression system.

Sensory Characteristics and Relative Sweetness of Tagatose and Other Sweeteners

The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener with various functional properties, compared to other sweeteners (sucrose, sucralose, erythritol, rebaudioside A), over a wide range of sweetness commonly found in foods and beverages (3% to 20% sucrose [w/v]). A total of 34 subjects evaluated aqueous solutions of the 5 sweeteners for the perceived intensities of sweetness, bitterness, astringency, chemical-like sensations, and sweet aftertaste, using the general version of the Labeled Magnitude Scale. The relationship between the physical concentrations of the sweeteners and their perceived sweetness (that is, psychophysical functions) was derived to quantify the relative sweetness and potency of the sweeteners. The results suggest that tagatose elicits a sweet taste without undesirable qualities (bitterness, astringency, chemical-like sensations). Out of the 5 sweeteners tested, rebaudioside A was the only sweetener with notable bitterness and chemical-like sensations, which became progressively intense with increasing concentration (P < 0.001). In terms of perceived sweetness intensity, the bulk sweeteners (tagatose, erythritol, sucrose) had similar sweetness growth rates (slopes > 1), whereas the high-potency sweeteners (sucralose, rebaudioside A) yielded much flatter sweetness functions (slopes < 1). Because the sweetness of tagatose and sucrose grew at near-identical rates (slope = 1.41 and 1.40, respectively), tagatose produced about the same relative sweetness to sucrose across the concentrations tested. However, the relative sweetness of other sweeteners to sucrose was highly concentration dependent. Consequently, sweetness potencies of other sweeteners varied across the concentrations tested, ranging from 0.50 to 0.78 for erythritol, 220 to 1900 for sucralose, and 300 to 440 for rebaudioside A, while tagatose was estimated to be approximately 0.90 times as potent as sucrose irrespective of concentration. The present study investigated the sensory characteristics and relative sweetness of tagatose, an emerging natural low-calorie sweetener, compared to other sweeteners. Study results suggest that tagatose elicits a sweet taste without undesirable qualities over a wide range of concentrations. Tagatose produced about the same relative sweetness to sucrose across the concentrations tested, while the relative sweetness of other sweeteners was highly concentration dependent. The present data provide a general guideline when considering the use of tagatose and other sweeteners in foods and beverages.

Efficient and rapid protein expression and purification of small high disulfide containing sweet protein brazzein in E. coli

Brazzein protein comes from an edible fruit, which has a long history of being a staple in the local human diet in Africa. The attractive features of brazzein as a potential commercial sweetener include its small size (53 amino acid residues), its stability over wide ranges of temperature and pH, and the similarity of its sweetness to sucrose. Heterologous production of brazzein is complicated by the fact that the protein contains four disulfide bridges and requires a specific N-terminal sequence. Our previous protocol for producing the protein from Escherichia coli involved several steps with low overall yield: expression as a fusion protein, denaturation and renaturation, oxidation of the cysteines, and cleavage by cyanogen bromide at an engineered methionine adjacent to the desired N-terminus. The new protocol described here, which is much faster and leads to a higher yield of native protein, involves the production of brazzein in E. coli as a fusion with SUMO. The isolated protein product contains the brazzein domain folded with correct disulfide bonds formed and is then cleaved with a specific SUMO protease to liberate native brazzein. This protocol represents an important advancement that will enable more efficient research into the interaction between brazzein and the receptor as well as investigations to test the potential of brazzein as a commercially viable natural low calorie sweetener.