Search Results (98)

Stevia rebaudiana leaves and extracts need to be promptly dried after harvest to prevent microbial activity and preserve their bioactive compounds, including glycosides, flavonoids, and essential oils. Effective drying also reduces moisture and volume, which lowers packaging, storage, and transportation costs. Therefore, innovative drying methods are necessary to maintain stevia’s physicochemical, sensory, and nutritional properties for functional food formulations. This review evaluates various drying technologies for stevia leaves and extracts, including convective hot air, infrared, vacuum, microwave, freeze, and shade drying, and their impacts on product quality and energy efficiency. It also explores the growing applications of dried and extracted stevia in food products. By comparing different drying methods and highlighting the benefits of stevia in these food formulations, this investigation aims to identify future research directions and optimization strategies for utilizing stevia as a natural sweetener and functional ingredient. Convective hot air drying at higher temperatures was found to be the most energy-efficient, though several studies have reported moderate degradation of key bioactive compounds such as stevioside and rebaudioside A, particularly at elevated temperatures and extended drying times. Infrared drying enhanced antimicrobial activity but resulted in lower levels of polyphenols and antioxidants. Vacuum drying effectively preserved anti-inflammatory compounds like flavonoids. Microwave drying presented strong protection of antioxidant activity and superior particle morphology. Freeze drying, while less energy-efficient, was the most effective at retaining antioxidants, polyphenols, and volatile compounds. Shade drying, though time-consuming, maintained high levels of polyphenols, flavonoids, and essential oils. Advanced techniques like spray drying and electrospraying have been reported to enhance the sensory qualities and stability of stevia extracts, making them ideal for food applications such as dairy and baked products, confectionery, syrups, snacks, jams, preserves, and meat products. Overall, stevia not only serves as a natural, zero-calorie sweetener but also contributes to improved health benefits and product quality in these diverse food formulations. Full article

Sweetness is a key dimension of sensory experience in food, and variations in the type and concentration of sweeteners can elicit distinct brain responses. In this study, electroencephalography (EEG) was employed to systematically evaluate neural activity elicited by different concentrations of sucrose solutions (1%, 3%, 5%, and 7%) and by non-nutritive sweeteners matched in perceived sweetness to a 7% sucrose solution (10% erythritol, 0.0133% sucralose, and 0.0368% stevioside). The results revealed that an increased sucrose concentration was associated with progressively weaker EEG signal intensity, suggesting that the brain can effectively distinguish sweetness intensity. Under iso-sweet conditions, different types of sweeteners induced significantly distinct EEG patterns, indicating that the nature of the sweetener modulates flavor perception at the neural level. Further analysis showed increases in both δ- and α-band power following sweet taste stimulation, with prominent activations observed in the frontal, parietal, and right temporal regions. These findings demonstrate the utility of EEG in detecting subtle differences in brain responses to sweeteners, offering new insights into the neural mechanisms underlying sweet taste perception. Full article

In this study, the decomposition processes of tabletop sweeteners based on steviol glycosides were investigated to determine the kinetic parameters of activation energy (E_a) and the logarithm of the pre-exponential factor (ln A) based on the converted fraction (α). These parameters were assessed using the Friedman and Ozawa–Flynn–Wall isoconversion methods with the NETZSCH Kinetics Neo software and the Model Free package. This study also aimed to explore the probable mechanism of the thermal decomposition of these materials. The thermal degradation of the samples was carried out in a temperature range of 150 to 400 °C under nitrogen flow, with heating rates of 5, 10, and 20 °C min⁻¹. The results indicated that both stevioside and steviol glycoside (E3) samples require higher energy to initiate their decomposition. Furthermore, the samples based on steviol glycosides exhibited distinct probable decomposition mechanisms: a model of two consecutive reactions followed by two competitive reactions for stevioside (FnFnFnFn model), three consecutive stages for the steviol glycoside sample (FnCnFn model), two consecutive stages for the steviol glycoside + erythritol sample (FnCn model), and three consecutive stages for the steviol glycoside + xylitol sample (FnFnFn model). Full article

This study investigated the effects of several light spectra on Stevia rebaudiana, analysing growth parameters, yield, and physiological responses within a controlled-environment agriculture (CEA) system. The experimental design involved different light treatments, including specific combinations of blue (435 nm and 450 nm), red (663 nm), and ultraviolet (UV) wavelengths (365 nm), to determine their impact on morphological development and biochemical properties, particularly focusing on the production of the sweetening compounds stevioside and rebaudioside A. Stevia rebaudiana plants cultivated from cuttings sourced from a reputable UK nursery (Gardener’s Dream Ltd., Glasgow, UK) were subjected to these spectral treatments over a period of five weeks under vertical farming conditions. Physiological measurements, such as chlorophyll fluorescence (Fv/Fm), stomatal conductance, and leaf temperature, were recorded, alongside growth metrics (plant height, leaf area, and biomass). This study also incorporated high-performance liquid chromatography (HPLC) to quantitatively analyse the influence of the light treatments on the sweetener concentration. The results demonstrated that targeted LED spectra, particularly those that include UV light and blue light (435 nm), significantly nhanced both the quantitative and qualitative attributes of stevia growth, indicating that strategic light management can markedly improve the nutritional and commercial yields of Stevia rebaudiana. This research contributes to the optimisation of light conditions in vertical farming systems, aiming to enhance agricultural efficiency and reduce the reliance on imported stevia by maximising local production capabilities. Full article

The purpose of this research is to identify and characterize lactic acid bacteria (LAB) species in bee bread produced by honey bees (Apis Cerana) in the east mountain area of Suzhou, China. We isolated three strains, Apilactobacillus kunkeei (S1), Lactiplantibacillus plantarum (S2), and Lacticaseibacillus pentosus (S3), with S2 producing the highest amount of lactic acid. Phylogenetic analysis indicated that these isolates, along with the type strain, formed a distinct sub-cluster within the LAB group. The strains exhibited non-hemolytic activity, lacked functional virulence factors, demonstrated high acid and bile tolerance, strong adhesion to intestinal cells, and antimicrobial activity against pathogens, collectively indicating their safety and high probiotic potential for therapeutic applications. Our studies demonstrated that S2 and S3 grew well in the presence of stevia leaf powder and steviosides, while S1 showed reduced growth and inhibitory effects. Importantly, the stevia-fermented strains exhibited strong probiotic potential along with significant antidiabetic, antioxidant, and antifungal properties in vitro. These findings highlight their potential applications in the food, feed, and pharmaceutical industries. Future research should focus on in vivo experiments to validate these results and evaluate compatibility among the strains before their application in functional foods. Full article

This study compared the effects of seed treatment with low-pressure cold plasma (CP) and atmospheric dielectric barrier discharge (DBD) plasma on morpho-biochemical traits in Stevia rabaudiana Bertoni plants cultivated by two methods: in soil and aeroponics. We investigated the impact of the treatments on the germination, plant growth, and content of secondary metabolites, namely steviol glycosides (SGs), rebaudioside A (RebA), and stevioside (Stev), as well as phenolic compounds and flavonoids. Seeds were treated for 2, 5, and 7 min with CP or DBD and 5 min with vacuum six days before sowing. All growth parameters in aeroponics exceeded the parameters of seedlings in the corresponding groups cultivated in soil. Seed treatments stimulated SGs biosynthesis in seedlings grown in soil, except for CP7. Although there were no stimulating effects of seed treatments on SGs in aeroponics, overall SG concentrations were considerably higher compared to plants cultivated in soil: the RebA+Stev concentration was 1.8–2-fold higher in the control, V5-, and CP-treated groups, and 1.3-fold higher in the DBD5 and DBD7 groups. Thus, aeroponic cultivation has the potential to improve the growth and synthesis of SGs in stevia, while a combination of aeroponics with seed treatments only increases the content of antioxidants and antioxidant activity. Full article

The use of in vitro cultures in plant breeding allows for obtaining cultivars with improved properties. In the case of Stevia rebaudiana Bert., genotypes with an appropriate rebaudioside A/stevioside ratio are desirable. The use of indirect organogenesis allows for the induction of somaclonal variation, which, consequently, results in obtaining variability within the regenerants. The Murashige and Skoog medium containing 4.0 mg × dm⁻³ 6-benzylaminopurine (BAP), 2.0 mg × dm⁻³ 1-naphthaleneacetic acid (NAA), and 2.0 mg × dm⁻³ 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in obtaining plants that were biochemically and genetically diverse. The obtained regenerants were characterized by an increased content of rebaudioside A and a better rebaudioside A/stevioside ratio. Genetic analysis using SCoT (start-codon-targeted) markers showed their diversity at the molecular level. Moreover, this study showed that genotype multiplication through six subsequent re-cultures does not cause variability at the genotype level and does not affect the steviol glycoside profile. This study is the first report on obtaining genotypes with higher rebaudioside A content and a more attractive rebaudioside A to stevioside ratio through the use of in vitro cultures. The improved regenerants can be used as parents in hybridization programs or directly as valuable new genotypes. Full article

Peptide aggregation inevitably occurs during hydrolysis, and insoluble peptide aggregates (ISPA) are used as feed for animals due to their poor water solubility and unpleasant bitter flavor. Ultrasound was used to fabricate soy peptide nanoparticles by reassembling ISPA, followed by spray-drying encapsulation to develop low-bitterness peptide microcapsules with soluble soybean polysaccharide (SSPS) and stevioside (STE) as wall materials. Powder properties, bitter taste, and the morphology of the microcapsules were evaluated. The formation of soluble peptide nanoparticles (<200 nm) was observed after ultrasound due to the reassembly of ISPA through the disruption of non-covalent intermolecular interactions. A gradual reduction in bitter taste was observed with increasing ultrasonic time. Moreover, spray-drying encapsulation with STE could effectively improve the flowability and wettability of the microcapsule powder owing to the rapid migration of surface-active STE to the atomized droplet surface, as evidenced by the lower angle of repose and wettability time. Peptide microcapsules with STE (spherical particles with smooth surfaces) exhibited lower density and reduced bitterness because STE (0–0.1%, w/w) exhibited an excellent bitter-masking effect. With high STE concentrations (>0.5%, w/w), microcapsules exhibited a higher bitter taste than unencapsulated peptides due to the increased surface distribution of STE on the microcapsules. These results provide an effective technique to improve the physicochemical properties of ISPA. Full article

Non-nutritive sweeteners (NNS) have been investigated for their potential to improve feed palatability and growth performance in pigs, although their use in swine production remains limited. This systematic review evaluates the effects of NNS on pigs, drawing from 18 studies published between 1990 and 2024. Following the PRISMA guidelines and using the PICOS framework, a total of 448 papers were initially identified, of which 18 met the inclusion criteria for review. The results are mixed: some studies suggest that NNS like stevioside, sucralose, and neotame may improve performance and reduce diarrhea, while others show limited or no effects. The impact of NNS on gut microbiota is similarly inconsistent, with some sweeteners promoting beneficial bacterial growth, while others show minimal changes in microbial diversity. This review emphasizes the need for more research to clarify the effects of NNS in pigs, particularly the mechanisms behind their influence on growth and gut health. Additionally, further studies are needed to determine optimal dosages and assess the long-term impacts of NNS on pig immune function and overall health. The findings highlight the current gaps in knowledge and suggest that more evidence is needed to understand the role of NNS in swine nutrition. Full article

Stevioside is a secondary metabolite of diterpenoid glycoside production in plants. It has been used as a natural sweetener in various foods because of its high sweetness and low-calorie content. In this study, we constructed a Saccharomyces cerevisiae strain for the complete synthesis of stevioside using a metabolic engineering strategy. Firstly, the synthesis pathway of steviol was modularly constructed in S. cerevisiae BY4742, and the precursor pathway was strengthened. The yield of steviol was used as an indicator to investigate the expression effect of different sources of diterpene synthases under different combinations, and the strains with further improved steviol yield were screened. Secondly, glycosyltransferases were heterologously expressed in this strain to produce stevioside, the sequence of glycosyltransferase expression was optimized, and the uridine diphosphate-glucose (UDP-Glc) supply was enhanced. Finally, the results showed that the strain SST-302III-ST2 produced 164.89 mg/L of stevioside in a shake flask experiment, and the yield of stevioside reached 1104.49 mg/L in an experiment employing a 10 L bioreactor with batch feeding, which was the highest yield reported. We constructed strains with a high production of stevioside, thus laying the foundation for the production of other classes of steviol glycosides and holding good prospects for application and promotion. Full article

Human amoebiasis still represents a major health problem worldwide. Metronidazole has been used as the most common drug to treat the disease; however, it is also known that the drug causes undesirable side effects. This has led to the search for new pharmacological alternatives which include phytochemical compounds with antiamoebic effects. We analyzed the amoebicidal activity of stevioside (STV), a diterpene glycoside present in Stevia rebaudiana, on trophozoites of E. histolytica. Different concentrations of STV were tested, and an inhibitory concentration of 50% of cell viability (IC₅₀) was determined with an exposition of 9.53 mM for 24 h. Trophozoites exposed to STV showed morphological changes evidenced by the decrease in the basic structures related to the movement and adherence to the substrate, as well as ultrastructural features characterized by a loss of regularity on the cell membrane, an increase in cytoplasmic granularity, and an increase in apparent autophagic vacuoles. Also, the decrease in cysteine protease expression and the proteolytic activity of trophozoites to degrade the cell monolayer were analyzed. A histological analysis of hamster livers inoculated with trophozoites and treated with STV showed changes related to the granulomatous reaction of the liver parenchymal tissue. Our results constitute the first report related to the possible use of STV as a therapeutic alternative in amoebiasis. Full article

Stevia rebaudiana Bertoni is a plant native to South America that has gathered much interest in recent decades thanks to diterpene glycosides, called steviosides, which it produces. These compounds are characterised by their sweetness, which is 250–300 times higher than saccharose, and they contain almost no caloric value. Stevia is currently also grown outside the South American continent, in various countries characterised by warm weather. This research aimed to determine whether it is viable to grow Stevia rebaudiana plants in Poland, a country characterised by a cooler climate than the native regions for stevia plants. Additionally, the impact of adding various dosages and forms of nitrogen fertiliser was analysed. It was determined that Stevia rebaudiana grown in Poland is characterised by a rather low concentration of steviosides, although proper nitrogen fertilisation can improve various characteristics of the grown plants. The addition of 100 kg or 150 kg of nitrogen per hectare of the field in the form of urea or ammonium nitrate increased the yield of the stevia plants. The stevioside content can be increased by applying fertilisation using 100 kg or 150 kg of nitrogen per hectare in the form of ammonium sulfate. The total yield of the stevia plants grown in Poland was lower than the yield typically recorded in warmer countries, and the low concentration of steviosides in the plant suggests that more research about growing Stevia rebaudiana in Poland would be needed to develop profitable methods of stevia cultivation. Full article

Steviosides extracted from the leaves of the plant Stevia rebaudiana are increasingly used in the food industry as natural low-calorie sweeteners. Phthalates in food are often assumed to arise from food containers or packaging materials. Here, experiments were carried out to identify the potential sources of DMP, DBP, DIBP, and DEHP in the leaves of stevioside through investigation of their content in native stevioside tissues, soils, and associated agronomic materials. The results show that phthalate contamination was present in all the samples tested, and the influence of regional factors at the provincial level on the content of plasticizers in stevia leaves was not significant. Phthalates in stevia leaves can be absorbed into the plant body through leaves and roots. Using resin removal, the phthalate content in stevioside glycosides was reduced to less than 0.05 ppm, and some indicators were far lower than the limit standard in EU food. Full article

Starting from isosteviol, a series of diterpenoid 1,3-aminoalcohol derivatives were prepared via stereoselective transformations. The acid-catalysed hydrolysis and rearrangement of natural stevioside produced isosteviol, which was transformed into the key intermediate methyl ester. In the next step, an 1,3-aminoalcohol library was prepared by the reductive amination of the intermediate 3-hydroxyaldehyde obtained from isosteviol in a two-step synthesis. To study the effect of the carboxylate ester function at position 4, the free carboxylic acid, benzyl ester and acryloyl ester analogues were prepared as elongated derivatives in comparison with our earlier results in this field. The antiproliferative activity of compounds against human tumour cell lines (A2780, HeLa, MCF-7 and MDA-MB-231) was investigated. In our preliminary study, the 1,3-aminoalcohol function with N-benzyl or (1H-imidazol-1-yl)-propyl substitution and benzyl ester moiety seemed essential for the reliable antiproliferative activity. The results obtained could be a good starting point to further functionalisation towards more efficient antiproliferative diterpenes. Full article