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Cyclamate is an artificial sweetener with high sweetness and low calories, and is a common sugar substitute for weight control and diabetic patients. However, excessive cyclamate consumption is associated with various health disorders, and hence it is prohibited as a food additive in many countries around the world. The current research proposes a light-shading reaction microfluidic PMMA/paper detection (MPD) system for determining the cyclamate concentration in food. In the current system, inject 10 μL of the extracted sodium cyclamate sample into the sample chamber of the MPD device, perform the diazotization reaction under shading conditions, and then suck it into the detection area through a paper strip, which consists of a paper chip embedded with modified Bratton-Marshall reagent. Once the paper chip is thoroughly wetted, the MPD device is inserted into a microanalysis box, where a fuchsia azo reaction compound is produced through heating at 40 °C for 3 min. The reaction complex is observed by a camera and the reaction image is wirelessly transmitted to a smartphone, and the concentration of sodium cyclamate is measured through the self-developed grayscale software. The results obtained for the sodium cyclamate samples with a concentration in the range of 50-1000 ppm show that the measured gray value changes linearly with the sodium cyclamate concentration, and the correlation coefficient (R

Extracts of Siraitia grosvenorii (Swingle), in Chinese known as Luo Han Guo (LHG), is authorized for use as a natural sweetener. LHG is rich in mogroside V that contains five glucoses, but also contains mogroside IIIE and analogues with fewer than three glucose units that cause an unpleasant aftertaste, limiting the use of the extract. Snailase was applied here to convert mogroside V in LHG extract in favor of siamenoside I formation, the sweetest mogroside with a taste similar to sucrose. For application, snailase was immobilized by adsorption to NKA (a macroporous resin), resulting in 10.9 U per g of adsorbed protein. Reuse of the NKA-adsorbed snailase was demonstrated for four cycles, and a continuous production of improved LHG extract at a 0.5 L scale had a productivity of 68.4 g/(L⋅day). The resulting product containing over 50% siamenoside I displayed an improved taste profile with satisfying safety toward HEK293T cells.

Thaumatin is an intensely sweet-tasting protein. Its sweetness persists when heated under acidic conditions, but disappears when heated at a pH above 7.0. To clarify how the structural features of thaumatin resist insoluble aggregation during heating under acidic conditions, we analysed its crystal structure obtained at pH 4.0, 6.0, and 8.0. Simultaneously, the melting temperature (Tm) at these pH levels was determined using differential scanning fluorimetry. At pH 4.0, the Tm of thaumatin was substantially lower and the overall B-factor value of its structure was higher than those at pH 6.0. Interestingly, the relative B-factor values for most lysine residues decreased as the pH reduced. These results suggest that the overall structure at pH 4.0 becomes flexible but the relative flexibility of some regions is lower than that at pH 6.0. Thus, the reduction in relative flexibility might play an important role in preventing thermal aggregation, thereby maintaining the sweetness.

In this study, terebinth coffee formulations were prepared with whole or skimmed milk with or without sugar/sweetener in order to study the matrix effect on the bioaccessibility of terebinth polyphenols. Quercetin glycosides and catechin were the major flavonoids identified in the terebinth formulations, whereas gallic, protocatechuic, syringic and ellagic acids were determined as the non-flavonoid compounds. The in vitro gastrointestinal digestion model results revealed that addition of whole milk to terebinth coffee increased the total bioaccessible flavonoids significantly (45%) (p 0.05), whereas skim milk addition did not result in any significant change. Furthermore, antioxidant capacity results measured with CUPRAC assay showed that addition of milk alone or together with sugar/sweetener increases the bioaccessibility of terebinth coffee antioxidants (36-70%) (p 0.05). Overall, terebinth coffee + whole milk + sugar formulation was found to contain the highest amount of bioaccessible flavonoid and non-flavonoid compounds (42.71-47.07 mg/100 g).

Knowing the mechanism of action of sweet taste receptors is important for the design of new, healthy sweeteners. However, little is known about the structures and recognition mechanisms of these receptors. 28 sweeteners were assessed by molecular docking, and 8 typical sweeteners were chosen to construct sweetener-T1R2-membrane systems to analyze interactions between receptor and sweeteners. Natural sweeteners with low-intensity sweetness, such as fructose and xylitol, were released from the Venus flytrap domain at ∼30 ns, with displacements greater than 50 Å. In contrast, artificial neotame and advantame bound stably to the receptor, within 5 Å. Van der Waals interactions were significant in high-intensity sweetener systems, imparting an energy difference of over 15 kcal/mol between neotame (artificial sweetener) and fructose (natural). These results provide a deeper understanding of the mechanisms of sweetener function and offer a new direction for the design of sweeteners.

Stevioside (ST) is currently considered as a highly-demanded natural and zero-caloric replacer of sucrose with several health-promoting properties. Nonetheless, its bitter aftertaste limits its use in the food industry. Herein, glucosyl steviosides were synthesized using primarily a food-grade lactic acid bacteria, Leuconostoc kimchii dextransucrase and conversion yield (%) was 40.3%. A glucose moiety was transferred stereo-selectively to ST by α-1,6-linkage and this is the first report about obtaining rebaudioside A (Reb-A) like glucosyl stevioside-2 (STG-2). Glucosyl steviosides revealed greatly improved stability up to 120 °C and remained stable over 32.1% and 58.12% in the pH (1.4) compared with 30.55% of ST. Moreover, the glucosylated steviosides improved the stability, reaching 95% after 30 days and Reb-A like compound (STG-2) especially exhibited higher stability in commercial beverages. Furthermore, the glucosyl steviosides showed over 1.92- and 2.24-fold decreases than that of enzymatically modified ST in the glucose generation rate test.

The purpose of this study was to elucidate the chemical basis for the sweet property produced by Gynostemma pentaphyllum and find new natural high-potency (HP) sweeteners. Sixteen new compounds (gypenosides YN 1-16) were obtained by sensory-guided isolation and identification, in which fifteen of them were sweet-tasting constituents with sweetness intensities 10-100 times higher than that of sucrose evaluated by human sensory panel test. Their structures were established by 1D and 2D nuclear magnetic resonance spectra, mass spectroscopy, infrared spectroscopy, UV-visible spectroscopy, and chemical method. Gypenoside YN 4 was the sweetest compound with a concentration of 15.504 ± 1.343 mg/kg, while gypenoside YN 12 has the highest concentration (1397.674 ± 12.948 mg/kg), as shown by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Structure-activity relationship analysis implied that the compounds' sweetness intensity was associated with side-chain substitutions at C-20 or the number of glucosyl groups at C-3. These new plant-derived natural products may be potential natural sweeteners.

The development of safe artificial sweeteners has attracted considerable interest in the food industry. Previous machine learning (ML) studies based on quantitative structure-activity relationships have provided some molecular principles for predicting sweetness, but these models can be improved via the chemical recognition of sweetness active factors. Our ML model, a soft-vote ensemble model that has a light gradient boosting machine and uses both layered fingerprints and alvaDesc molecular descriptor features, demonstrates state-of-the-art performance, with an AUROC score of 0.961. Based on an analysis of feature importance and dataset, we identified that the number of nitrogen atoms that serve as hydrogen bond donors in molecules can play an essential role in determining sweetness. These results potentially provide an advanced understanding of the relationship between molecular structure and sweetness, which can be used to design new sweeteners based on molecular structural dependence.

Parabens are compounds used as chemical preservatives in cosmetics, drugs, and food. Some can cause adverse effects on human health. In this study, a square wave voltammetric method using a glassy carbon electrode was developed for simultaneous determination of methyl, ethyl, propyl, and butyl parabens in sweeteners. To overcome the strong overlap of voltammetric signals caused by calibrated and uncalibrated constituents, unfolded partial least squares with residual bilinearization (U-PLS/RBL) was used. The U-PLS/RBL calibration model was constructed and evaluated using a validation set obtained using a Taguchi design. Satisfactory and unbiased results were obtained with a linear response in the range of 0.78–4.48 μmol L−1 and recoveries from 82.64% to 121.77%. As far as the authors know, a voltammetric method that simultaneously determines four parabens in complex samples such as sweeteners without any previous pretreatment has not yet been reported in the literature.

Surface active agents derived from the non-toxic sweetener sucralose and fatty acids of different chain length were synthesized. Obtained compounds were characterized chemically and with regard to their properties as emulsifying agents, antimicrobial preservatives and fat-soluble sweeteners. Results show that sucralose-fatty acid esters are possible multi-purpose additives, compatible with both cosmetic and edible emulsions, as well as purely oil-based, waterless formulations. Their relative effectiveness in those applications varies, and is highly dependent on the fatty acid chain length, with hydrophobic/hydrophilic character strongly impacting both emulsifying and antimicrobial properties. While the structural differences between sucrose and sucralose proved to be enough to push all of the newly synthesized compounds out of the detergent/solubilizer category of surfactants, the retention of the substrate's high sweetness is an indication that non-bitter compounds with washing capabilities are possible to obtain.

Brown sugar (non-centrifugal cane sugar) is popular for its pleasant caramel-like aroma and sweetness. Vacuum simultaneous steam distillation and extraction (V-SDE) and gas chromatography-mass spectrometry (GC-MS) was used to study the volatile fraction of brown sugar. To further determine the aroma-active compounds in brown sugar, gas chromatography-mass spectrometry-olfactometry (GC-MS-O) were used in conjunction with aroma extraction dilution analysis (AEDA), odor activity values (OAVs), and sensory evaluation to analyze the effects of the key aroma-active compounds on sweetness. A total of 37 aroma-active compounds were obtained, mainly including ketones, pyrazines, alkanes, phenols and alcohols, which contributed caramel, sweet and fruity notes to brown sugar. Among them, furfural, benzeneacetaldehyde, 2,3-butanedione, β-damascenone, 2-methoxyphenol, dihydro-2-methyl-3(2H)-furanone, 2-furanmethanol and butyrolactone could significantly enhance the sweetness of sugar solution because of the congruency of the aroma attributes and sweetness.

In this study, we present a framework comprises of several independent modules which are built upon data based (structure activity relationship and classification model) and structure (molecular docking) based for identifying possible sweeteners from a vast database of natural molecules. A large database, Universal Natural Products Database (UNPD) consisting of 213,210 compounds was screened using the developed framework. At first, 10,184 molecules structurally similar to the known sweeteners were identified in the database. Further, 1924 molecules from these screened molecules were classified as sweet molecules. The shortlisted 1354 molecules were subjected to ADMET analysis. Finally, 60 molecules were arrived at with no toxicity and acceptable oral bioavailability as potential sweetener candidates. Further, molecular docking of these molecules on sweet taste receptor performed to obtain their binding energy, binding sites and correlation with sweetness index. The developed framework offers a convenient route for fast screening of molecules prior to synthesis and testing.

In response to growing concerns about the consumption of artificial sweeteners, the demand for natural sweeteners has recently increased. Mogroside V is a common natural sweetener extracted from the fruit of Siraitia grosvenorii, but its taste should be improved for marketability. Here, we screened various microbes for the ability to perform selective hydrolysis of glycosidic bonds in mogroside V, converting it to siamenoside I, which has a higher sweetening power and better taste than other mogrosides. Dekkera bruxellensis showed the most promising results in the screen, and the Exg1 gene (coding for a β-glucosidase) of D. bruxellensis was cloned and purified. We then used HPLC-MS/MS to assess the β-glucosidase activity of purified enzymes on p-nitrophenyl β-glucoside and mogroside V. The results demonstrated that D. bruxellensis had a unique enzyme that can selectively hydrolyze mogrol glycosides and promote the conversion of the natural sweetener mogroside V to siamenoside I.

The rising awareness about the adverse health effects of high sugar consumption has led to regulatory amendments for triggering sugar reduction in food products. Sugar reduction in yogurt is a challenging endeavor due to the changes in taste, flavor, texture, maintenance of food functionality, shelf-life, cost and consumer acceptability. A review of the scientific literature, patents, and web articles revealed several approaches being explored by the dairy industry to reduce the sugar addition. A careful assessment of these strategies and their critical analysis is presented in this review. The strategies for sugar reduction involve multifaceted approaches including the use of alternative low-calorie sweeteners, honey, fruit preparations, novel cultures, lactase addition, inulin fiber addition, and flavor interventions. Much of the work so far has focused on development of low-calorie alternative sweeteners, and novel sweeteners-based solutions are evolving. The use of food structuring approaches remains to be explored for sugar reduction in yogurt.

Quantitative structure activity relationship (QSAR) models appear to be an ideal tool for quick screening of promising candidates from a vast library of molecules, which can then be further designed, synthesized and tested using a combination of rigorous first principle simulations, such as molecular docking, molecular dynamics simulation and experiments. In this study, QSAR models have been built with an extensive dataset of 487 compounds to predict the sweetness potency relative to sucrose (ranging 0.2–220,000). The whole dataset was randomly split into training and test sets in a 70:30 ratio. The models were developed using Genetic Function Approximation (Rtest2 = 0.832) and Artificial Neural Network (Rtest2 = 0.831). Our models thus offer a convenient route for fast screening of molecules prior to synthesis and testing. Additionally, this study can supplement a molecular modelling approach to improve binding of molecules with sweet taste receptors, leading to design of novel sweeteners.

Nowadays, computational approaches have drawn more and more attention when exploring the relationship between sweetness and chemical structure instead of traditional experimental tests. In this work, we proposed a novel multi-layer sweetness evaluation system based on machine learning methods. It can be used to evaluate sweet properties of compounds with different chemical spaces and categories, including natural, artificial, carbohydrate, non-carbohydrate, nutritive and non-nutritive ones, suitable for different application scenarios. Furthermore, it provided quantitative predictions of sweetness. In addition, sweetness-related chemical basis and structure transforming rules were obtained by using molecular cloud and matched molecular pair analysis (MMPA) methods. This work systematically improved the data quality, explored the best machine learning algorithm and molecular characterizing strategy, and finally obtained robust models to establish a multi-layer prediction system (available at: https://github.com/ifyoungnet/ChemSweet ). We hope that this study could facilitate food scientists with efficient screening and precise development of high-quality sweeteners.

Food producers have leaned towards alternative natural and synthetic sweeteners in food formulations to satisfy market demands. Even so, several synthetic sweeteners (e.g., aspartame, saccharin, sucralose) are becoming less popular due to health-related concerns, lower nutritional values, and controversies around their safety. Conversely, natural sweeteners confer favourable customer perceptions due to their association to a healthier lifestyle and higher nutritional values. This article discusses the evidence of natural sweeteners in the available commercial products. A comprehensive review of natural sweeteners is presented, which includes their resources, properties and extraction methods, as well as a discussion on several emerging technologies that offer improvements to the traditional extraction methods. Finally, the progress of natural sweeteners in the food industry is assessed, and the commercial food products containing these natural sweeteners are mentioned.

Leaves of a new variety of Stevia rebaudiana with a high content of rebaudioside A were pretreated with ethanol. The ethanolic extract showed high antioxidant potential and 39 compounds were identified, by UPLC/HRMS, among them one not yet mentioned in the literature for stevia leaves. From the in natura leaves and pretreated leaves, the conditions of aqueous extraction of steviol glycosides were investigated using response surface methodology. The aqueous extracts obtained were purified by ion exchange chromatography techniques and membrane separation methods. The recuperation of steviol glycosides was 4.02g for pretreated leaves and 2.20g for in natura leaves. The level of purity was, respectively, 87% and 84.8%. The results obtained demonstrate that pretreatment increases the yield and purity level of stevia sweeteners by the use of environmentally friendly methodologies and the final product presented acceptable sensory characteristics.

Sunflower butter use as an allergen-free alternative to tree and legume nut butter in baking is limited by chlorogenic acid induced greening that occurs at alkaline pH. Limited information is available on controlling this greening in a food matrix. This study examined how different liquid sweeteners and relative humidity influenced greening of sunflower butter cookies. Doughs had similar initial pH (7.52-7.66) which increased to 8.44-9.13 after baking as ranked: xylitol>maple syrup>corn syrup>honey>agave syrup. Cookies made with maple syrup had the highest moisture and greening corresponding with lowest free chlorogenic acid. The % greening followed the same trend as greening intensity, and was positively correlated (r=0.9101) with chlorogenic-lysine adduct content. Our findings provide an ingredient solution to controlling greening, as results demonstrate that greening can be promoted with high relative humidity storage, and use of high moisture and pH ingredients. Unwanted greening can be inhibited by simply changing the liquid sweetener.

A comparative study of the bioaccessibility of bioactive compounds and antioxidant capacity in a fruit juice-Stevia rebaudiana mixture processed by pulsed electric fields (PEF), high voltage electrical discharges (HVED) and ultrasound (USN) technology at two equivalent energy inputs (32–256 kJ/kg) was made using an in vitro model. Ascorbic acid was not detected following intestinal digestion, while HVED, PEF and USN treatments increased total carotenoid bioaccessibility. HVED at an energy input of 32 kJ/kg improved bioaccessibility of phenolic compounds (34.2%), anthocyanins (31.0%) and antioxidant capacity (35.8%, 29.1%, 31.9%, for TEAC, ORAC and DPPH assay, respectively) compared to untreated sample. This was also observed for PEF treated samples at an energy input of 256 kJ/kg (37.0%, 15.6%, 29.4%, 26.5%, 23.5% for phenolics, anthocyanins, and antioxidant capacity using TEAC, ORAC and DPPH method, respectively). Consequently, pulsed electric technologies (HVED and PEF) show good prospects for enhanced bioaccessibility of compounds with putative health benefit.

Sucralose is widely used as non-caloric intense artificial sweetener. It was previously considered to be thermally stable and safe. This was based on studies performed in the early 1990s. However, significant concerns have been raised more recently regarding the physicochemical stability of sucralose at high temperatures in the context of food processing. Over the last decades different independently performed studies indicated that sucralose is decomposed at high temperatures, e.g. through cooking. This - in turn - was considered to be associated with the formation of chlorinated potentially toxic compounds, such as chloropropanols and dioxins. In this review, the literature on thermal stability of sucralose and the generation of potentially toxic compounds was assessed and comparatively discussed. Considering the validity of published data, we conclude that sucralose can be degraded at high temperatures, e.g. during cooking or baking of sucralose-containing foods. As a consequence potentially toxic chlorinated compounds might be generated.

High content of steviol glycosides in stevia leaves is a cause of their high popularity as. a natural sweetener of various sugar-free food products. Stevioside (13-[(2-O-β- d -glucopyranosyl-β- d -glucopyranosyl)oxy]-ent-kaur-16-en-19-oic acid β- d -glucopyranosyl ester) is one of the main steviol glycosides in stevia leaves known for its hydrolytic instability responsible for the formation of simple steviol glucosides (steviolbioside, rubusoside, steviol monoside) and steviol. However, the formation of hydroxy and alkoxy adducts of stevioside and of its hydrolysis products has not yet been reported. The performed experiments prove that water and alkoxy adducts are formed not only during temperature processing of stevioside but also of stevia and stevia-containing food products. Their quantities depend on environment pH, water concentration and food composition. Although they are formed in small amounts their biological activity is unknown and should be recognized.

Turanose, a potential novel sweetener in food industry, can be synthesized by Neisseria polysaccharea amylosucrase (NpAS). However, the malt-oligosaccharide byproduct affects the yield. In this study, the NpAS mutant G396S, which was expected to interfer with the extension of glucan by increasing steric hindrance, was obtained. The NpAS and G396S were heterologously expressed in Bacillus subtilis and enzyme properties were analyzed. Results showed that the polymerization activity of G396S was decreased. In addition, the mutant was used in the preparation of turanose. When using 2 M sucrose as substrate, the turanose yield reached 410.4 g·L−1, an increase of 61 g·L−1 compared with that of NpAS. When fructose was added, the optimal fructose concentration for G396S decreased from 0.75 M to 0.5 M. The turanose production reached 523 g·L−1 with the conversion rate of 76.5%. This study contributes the use of turanose in food industry.

Poor aqueous solubility of some minor steviol glycosides (SGs) has prevented their potential widespread usage as non-nutritional high intensity sweeteners in beverage industry. Rebaudioside B (reb B) is one of the minor SGs found in stevia leaf, and has a better taste quality than many of the major SGs. However, reb B suffers from poor aqueous solubility and low dissolution rate, which greatly limits its application, especially in beverages. In our effort to enhance its solubility by using natural means, we discovered that under certain conditions reb B forms hemihydrate crystal, which has much lower solubility and dissolution rate than commercial powder reb B product. The crystal was characterized by Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD). This may offer more insight into the interaction of SGs with water at molecular level, and therefore provide new guidance on current efforts to enhance the solubility of SGs.

The research aimed to study the effect of stevia, xylitol, and corn syrup on the physical, physicochemical, and sensory properties of velvet tamarind chewy candy (VTCC). The content of sweeteners was optimized using stevia (5.5–6%), xylitol (5.5–6%), and corn syrup (7.5–8.5%) by mixture design (d-optimal) with 3 centerpoints and response surface methodology (RSM). The sweeteners in optimized VTCC consisted of velvet tamarind powder (40.5%), water (40%), stevia (6%), xylitol (6%), and corn syrup (7.5%) which provided the approximation error between prediction and observation values: of color (a* and b*), hardness, adhesiveness, gumminess, bioactive activities, and sensory properties within the range of 0.07–9.69%. The optimized VTCC using stevia and xylitol can reduce the sugar content by up to 60%. The sensory preference scores of VTCC from consumer acceptance were slightly like (6.1–6.9) which indicated that the VTCC with stevia and xylitol can provide satisfaction in all evaluated attributes and can be applied to this concept to create fruit chewy candy using stevia and xylitol.

The low thermal stability of the sweet-tasting proteins limited their applications in food industry. Improve their thermal stability is the key to developing their applications in food processing. In the present study, saturation mutagenesis was performed on 4 sweet-tasting proteins, brazzein (988 mutations), curculin (2109 mutations), monellin (1824 mutations) and thaumatin (3933 mutations), using structural calculations in order to find more thermal stable mutations. The obtained results indicated that our calculated ΔΔG value (ΔΔG 0 stabilizing, ΔΔG 0 destabilizing) was a good predictor for predicting changes in thermal stability caused by mutations. Moreover, mutating the negatively charged residues to the other non-negatively charged amino acids was an efficient way to improve the thermal stability of the investigated sweet-tasting proteins. In addition, some promising mutations sites were identified for improving thermal stability using mutagenesis. This study provides useful information for future protein engineering to improve the thermal stability of the sweet-tasting proteins.

Artificial sweeteners have been widely used as replacements for sugars in foods. Rapid determination of artificial sweeteners contained in various foods are highly desirable for the routine analysis. Here, we report a robust approach based on direct analysis in real time coupled with QTRAP mass spectrometry to screen and quantitate simultaneously seven artificial sweeteners, including aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate and alitame in alcoholic drinks. The detection method merely involved a simple sample pretreatment process, with a good linearity, low limit of quantification, satisfied recovery and relative standard deviation for each target compound. More importantly, the approach is highly sensitive and accurate in monitoring the seven artificial sweeteners in whisky, Chinese liquors, beer and wines obtained from the supermarket. The results demonstrated that the approach described here could be suitable for large-scale application in routine quality control analysis of artificial sweeteners.

Two electrophoretic methods with contactless conductivity detection have been developed for determination of the content of rebaudioside A and stevioside in samples of sweeteners and beverages prepared from extracts of the plant Stevia rebaudiana Bertoni. The total content of rebaudioside A and stevioside can be determined in a fused silica capillary with an inner diameter of 10 μm and total length of 31.5 cm in optimised background electrolyte with the composition 170 mM H 3 BO 3 /LiOH (pH 9.0). The combined peak of the two glucosides is characterised by a migration time of 54 s, which completely separates it from EOF. INST coating solution in an amount of 0.5% v / v , which effectively suppresses the electroosmotic flow, was added to the background electrolyte for mutual separation of rebaudioside A and stevioside. The CE method with suppression of EOF is characterised by complete separation of rebaudioside A and stevioside, LOD is 0.3 mg/L (0.1 μM).

Glucosyl stevioside was synthesized via transglucosylation by dextransucrase from Leuconostoc citreum KM20 (LcDexT), forming α-d-glucosyl stevioside. A production yield of 94% was reached after 5days of LcDexT reaction at 30°C. Glucosyl stevioside induced a 2-fold improved quality of taste and sweetness, compared to stevioside. After 15days of storage at 25°C, 98% of glucosyl stevioside in an aqueous solution was present in a soluble form, compared to only 11% for stevioside or rebaudioside A. Furthermore, glucosyl stevioside exhibited a similar or improved stability in commercially available soft drinks, when compared to stevioside and rebaudioside A. These results suggest that glucosyl stevioside could serve as a highly pure and stable sweetener in soft drinks.

Rebaudioside-A is the second most abundant sweet diterpene glycoside (1-3%) present in the leaves of Stevia rebaudiana Bertoni, and is now being considered as a possible sucrose substitute due to its pleasant organoleptic properties and associated health benefits. In the present study, a novel in situ enzymatic transglycosylation of stevioside has been developed by pre-treating the stevia leaves with cellulase and adding soluble starch as the glucosyl donor. The results confirm that the transglycosylation of stevioside led to an enrichment in the rebaudioside-A content from 4% to 66%. This was further purified by multiple column chromatography to obtain 95% pure rebaudioside-A. The isolated rebaudioside-A showed concentration-dependent α-glucosidase inhibitory activity with IC50=35.01 μg/ml. Thus the study highlights the biotransformation of stevioside present in stevia leaves to rebaudioside-A by a simple, inexpensive and eco-friendly process that has commercial potential.

Quantitative and qualitative determination of sucrose from complex tastant mixtures using Cu foam electrode was investigated in this study. Cu foam was prepared and its three-dimensional (3-D) mesh structure was characterized by scanning electron microscopy (SEM). Cu foam was utilized as working electrode in three-electrode electrochemical system. Cyclic voltammetry (CV) scanning results exhibited the oxidation procedure of sucrose on Cu foam electrode. Amperometric i-t scanning results indicated that Cu foam electrode selectively responded to sucrose from four tastant mixtures with low limit of detection (LOD) of 35.34 μM, 49.85 μM, 45.89 μM, and 26.81 μM, respectively. The existence of quinine, NaCl, citric acid (CA) and their mixtures had no effect on sucrose detection. Furthermore, mixtures containing different tastants could be discriminated by non-linear double-layered cascaded series stochastic resonance (DCSSR) output signal-to-noise ratio (SNR) eigen peak parameters of CV measurement data. The proposed method provides a promising way for sweetener analysis of commercial food.

The aim of this study was to describe the changes in phenolic compounds, antioxidant activity and colour of sour cherry puree supplemented with different natural sweeteners (sucrose, palm sugar, erythritol, xylitol, steviol glycoside, Luo Han Kuo), and natural prebiotic (inulin). A total of 18 types of polyphenolic compounds were assessed in the following sour cherry puree by LC-MS-QTof analysis, before and after 6 months of storage at 4 °C and 30 °C. Total phenolics determined by UPLC-PDA-FL was 1179.6 mg/100 g dm. In samples with addition of sweeteners the content of phenolic compounds ranged from 1133.1 (puree with steviol glycoside) to 725.6 mg/100 g dm (puree with erythritol), and the content of these compounds strongly affected on antioxidant activity. After 6-month storage, protective effects of some additives (palm sugar, erythritol, steviol glycoside, xylitol and inulin) on the polyphenol content, especially on anthocyanins and consequently on colour, and antioxidant activity were noticed. The results showed that some natural sweeteners might be interesting from a nutritional as well as commercial and pharmaceutical perspective.

Potato accumulates large amounts of soluble sugar during cold storage periods. However, a system based understanding of this process is still largely unknown. Here, we compared the dynamic cold-responded transcriptome of genotypes between cold-induced sweetening resistant (CIS-R) and cold-induced sweetening sensitive (CIS-S) in tubers. Comparative transcriptome revealed that activating the pathways of starch degradation, sucrose synthesis and hydrolysis could be common strategies in response to cold in both genotypes. Moreover, the variation in sugar accumulation between genotypes may be due to genetic differences in cold response, which could be mainly explained: CIS-R genotype was active in starch synthesis and attenuated in sucrose hydrolysis by promoting the coordinate expression of aseries ofgenes involved in starch-sugar interconversion. Additionally, transcription factors, the candidate master regulators of starch-sugar interconversion, were discussed. Taken together, this work has provided an avenue for studying the mechanism involved in the regulation of the CIS resistance.

Stevioside is the main and the sweetest glycoside of stevia plant. It is attractive as a natural sweetener to diabetics and others on carbohydrate-controlled diets. This paper discusses the stability of stevioside under food processing conditions. It was found that stevioside was transformed not only to rubusoside, steviolbioside, steviol monoside and steviol but also to previously unknown stevioside α-anomer and rubusoside α-anomer. Those two identified stevioside transformation products are formed not only during the heating of acidic, neutral and alkaline stevioside standard solutions and stevia leaves suspensions in water and ethanol/water solvents but also during the processing of foods containing stevia. Apart from presenting the new compounds, the paper additionally shows that the recombination of sugar moiety with steviolbioside molecule in MS/ESI source can occur. The effect of molecule recombination in the MS source is known from the literature; however, it has not been reported previously in relation to stevioside derivatives.

Fourier transform infrared (FTIR) spectroscopy calibrations were developed to simultaneously determine the multianalytes of five artificial sweeteners, including sodium cyclamate, sucralose, sodium saccharin, acesulfame-K and aspartame. By combining the pretreatment of the spectrum and principal component analysis, 131 feature wavenumbers were extracted from the full spectral range for modelling to qualitative and quantitative analysis. Compared to random forest, k nearest neighbour and linear discriminant analysis, support vector machine model had better predictivity, indicating the most effective identification performance. Furthermore, multivariate calibration models based on partial least squares regression were constructed for quantifying any combinations of the five artificial sweeteners, and validated by prediction data sets. As shown by the good agreement between the proposed method and the reference HPLC for the determination of the sweeteners in beverage samples, a promising and rapid tool based on FTIR spectroscopy, coupled with chemometrics, has been performed to identify and objectively quantify artificial sweeteners.

This study investigated sucrose catabolism during cold-induced sweetening (CIS) and its impact on the quality of sweet potato chips of cultivars with varied levels of tolerance to cold during storage at 6 and 13 °C. In contrast to cultivar Beauregard, cultivar BRS Rubissol and BRS Cuia were cold-sensitive exhibiting intense symptoms of chilling injury at 6 °C. CIS in the sensitive cultivars BRS Rubissol and BRS Cuia was characterized by low accumulation of reducing sugar (RS), high non-reducing sugars content, low invertase activity and high sucrose synthase (SuSy) activity. In the tolerant cultivar Beauregard, the high content of RS was due to high invertases activity. In the three cultivars, the darkening of chips was more influenced by the non-reducing sugars, instead of RS. Our results suggest that SuSy was induced by cold stress in cold-sensitive cultivar, but did not contribute to the CIS in sweet potato.

Effects of various co-pigment sources [gallic acid (GA) and the extracts of rose leaf (RLE), cherry stem (CSE), pomegranate rind (PRE) and sour cherry stem (SCSE)] on anthocyanins and colour in strawberry nectars (SNs), sweetened with sucrose (SNS), maltose syrup (SNM) and honey (SNH), were investigated during storage at 20 °C. Honey elicited the highest stabilities of anthocyanins, hyperchromic and bathochromic effects in SNs containing all co-pigment sources, except for PRE. PRE co-pigments were composed of mainly tannins which could interact with SNs proteins and honey proline. As a result of these interactions, PRE co-pigments could not show significant contribution to protection of SN anthocyanins and colour. Among co-pigment sources, SCSE caused the highest stabilities of anthocyanins, hyperchromic effect and colour density, regardless of sweetener used. Interactions between SCSE phenolic acids, and pelargonidin-3-glucoside and pelargonidin-3-rutinoside resulted in the most stable co-pigmentation effect. Thus, SCSE should be preferred in beverages containing pelargonidin-based anthocyanins.

Steviol glycosides are intense natural sweeteners used in foods and beverages. Their acceptable daily intake, expressed as steviol equivalents, is set at 0-4 mg/kg body weight. We report the development and validation of a RP-HPLC method with fluorometric detection of derivatized isosteviol, formed by acid hydrolysis of steviol glycosides. Dihydroisosteviol was used as an internal standard. Using this method, the amount of steviol equivalents in commercial steviol glycoside mixtures and different foods can be directly quantified. The method was successfully tested on strawberry jam, low-fat milk, soft drink, yogurt and a commercial mixture of steviol glycosides. Calibration curves were linear between 0.01 and 1.61 mM steviol equivalents, with a quantification limit of 0.2 nmol. The % RSD of intra-day precision varied between 0.4% and 4%, whereas inter-day precision varied between 0.4% and 5%, for high and medium concentrations, and between 3% and 8% for low concentrations. Accuracy of the analysis varied between 99% and 115%.

Exposure of the naturally-occurring sweetener monatin to light and metal ions results in loss of both parent monatin and total indole (monatin plus monatin lactone/lactam) in mock beverage solutions, with an accompanying decrease in sweetness. In this study potential protective strategies to prevent degradation were investigated. Metal ion chelating resin, or the chelators EDTA and desferrioxamine decreased monatin and indole loss for solutions kept either in darkness or exposed to light. Tannic acid and Chinese bayberry extract both afforded protection, but this did not arise from a light filtering effect. Plastics with defined absorbance characteristics provided protection with this being wavelength dependent; yellow transparent PET plastic was most effective. The contribution of these interventions (metal ion removal/binding; antioxidant; light absorption) was additive, with combinations providing the greatest protective effect against monatin and indole loss. These results indicate that it is possible to minimise monatin degradation by appropriate choices of treatments, additives and container.