Sweetness Potency Research Articles

ChemSweet: An AI-driven computational platform for next-gen sweetener discovery

Nowadays, the overconsumption of artificial sweeteners and their related adverse health impacts have proposed an urgent need to develop safe and healthy alternatives. Herein, we introduce ChemSweet, an AI-based platform for the rapid discovery of potential sweet molecules (http://chemsweet.ddai.tech) with the consideration of their physicochemical properties, sweetness profile, and health risks at the same time. Machine learning prediction models of four important physicochemical and four toxicity properties were established and integrated with the platform to evaluate the candidate molecules' biosafety and stability during the processing processes. Then, a new sweet taste prediction system was developed which ensures the sweet evaluation of six specific kinds of sweeteners. To facilitate the practical application of ChemSweet, the SuperNatural database was integrated for the rational screening of promising new sweeteners. We successfully identified 294 potential sweeteners that simultaneously meet the multiple anticipated criteria. We believe that ChemSweet will serve as a useful tool for identifying safe and healthy sweeteners while reducing the timeframe and high experimental costs.

Sweetness interaction between a novel glycosylated rebaudioside A and various sweeteners in a binary mixture system.

The present study investigated the sweetness interaction and the sensory characteristics of a novel glycosylated rebaudioside A (g-reb_A) when mixed with other sweeteners. Binary sweetener mixtures were formulated by mixing g-reb_A with four types of sweeteners (sucrose, aspartame, acesulfame-K, saccharin). The sweetness potencies of sweeteners were measured at various concentrations. G-reb_A was mixed with each of the four other sweeteners at the concentration ratio of 35:65 or 50:50 to match the sweetness of a 10% sucrose solution. A generic descriptive analysis was conducted to evaluate the binary samples compared to the 10% sucrose solution. Most binary mixtures exhibited an additive effect on sweetness. A marginal sweetness synergistic effect was observed when g-reb_A was mixed with sucrose at the 50:50 ratio. The sensory characteristics of the binary mixture depended on the type of sweetener mixed with g-reb_A. Mixtures of g-reb_Aacesulfame-K or g-reb_Asaccharin elicited significantly higher bitter taste than the other binary mixtures.

Effect of the consumption of brazzein and monellin, two recombinant sweet-tasting proteins, on rat gut microbiota.

Sweet-tasting proteins (SPs) are proteins of plant origin initially isolated from tropical fruits. They are thousands of times sweeter than sucrose and most artificial sweeteners. SPs are a class of proteins capable of causing a sweet taste sensation in humans when interacting with the T1R2/T1R3 receptor. SP thaumatin has already been introduced in the food industry in some countries. Other SPs, such as monellin and brazzein, are promising products. An important stage in researching SPs, in addition to confirming the absence of toxicity, mutagenicity, oncogenicity, and allergenic effects, is studying their influence on gut microbiota. In this paper we describe changes in the composition of rat gut microbiota after six months of consuming one of two recombinant SPs-brazzein or monellin. A full length 16S gene sequencing method was used for DNA library barcoding. The MaAsLin2 analysis results showed noticeable fluctuations in the relative abundances of Anaerocella delicata in brazzein-fed rat microbiota, and of Anaerutruncus rubiinfantis in monellin-fed rat microbiota, which, however, did not exceed the standard deviation. The sucrose-fed group was associated with an increase in the relative abundance of Faecalibaculum rodentium, which may contribute to obesity. Overall, prolonged consumption of the sweet proteins brazzein and monellin did not significantly change rat microbiota and did not result in the appearance of opportunistic microbiota. This provides additional evidence for the safety of these potential sweeteners.

Microbial-Driven Synthesis and Hydrolysis of Neohesperidin Dihydrochalcone: Biotransformation Process and Feasibility Investigation.

A novel yeast-mediated hydrogenation was developed for the synthesis of neohesperidin dihydrochalcone (NHDC) in high yields (over 83%). Moreover, whole-cell catalytic hydrolysis was also designed to hydrolyze NHDC into potential sweeteners, hesperetin dihydrochalcone-7-O-glucoside (HDC-G) and hesperetin dihydrochalcone (HDC). The biohydrogenation was further combined with whole-cell hydrolysis to achieve a one-pot two-step biosynthesis, utilizing yeast to hydrogenate C═C in the structure, while Aspergillus niger cells hydrolyze glycosides. The conversion of NHDC and the proportion of hydrolysis products could be controlled by adjusting the catalysts, the components of the reaction system, and the addition of glucose. Furthermore, yeast-mediated biotransformation demonstrated superior reaction stability and enhanced safety and employed more cost-effective catalysts compared to the traditional chemical hydrogenation of NHDC synthesis. This research not only provides a new route for NHDC production but also offers a safe and flexible one-pot cascade biosynthetic platform for the production of high-value compounds from citrus processing wastes.

Determination of Possible Adulteration and Quality Assessment in Commercial Honey.

This study aims to predict several quality traits in commercial honey samples simultaneously and to reveal possible honey adulteration using a field-deployable portable infrared spectrometer without any sample preparation. A total of one hundred and forty-seven commercial honey samples were purchased from local and online markets in Turkey and the United States of America (USA), and their soluble solids (°Brix), pH, free acidity, moisture, water activity (aw), glucose, fructose, sucrose, and hydroxymethyl furfural (HMF) contents were determined using reference methods. The HMF (n = 11 samples) and sucrose (n = 21) concentrations were higher than the regulatory limits in some tested samples. The exceeding HMF content may imply temperature abuse during storage and prolonged storing. On the other hand, high sucrose content may indicate possible adulteration with commercial sweeteners. Therefore, soft independent modeling of class analogies (SIMCA) analysis was conducted to reveal this potential sweetener adulteration in the samples, and the SIMCA model was able to identify all the flagged samples. The suggested FT-IR technique may be helpful in regulatory bodies in determining honey authenticity issues as well as assessing the quality characteristics of honey samples in a shorter period and at a lower cost.

Screening of elite germplasms for industrially valuable medicinal crop Stevia rebaudiana for stevioside and rebaudioside A production: An HPTLC-linked chemotaxonomic assessment

Stevia rebaudiana Bertoni (Asteraceae) is a South American perennial herb native to the Paraguay region. It is high-value commercial crop in the food industry because of an array of bioactive diterpenoid glycosides, the most important of which are the steviol glycosides, stevioside (Stev) and rebaudioside A (Reb A). Standardized extract from Stevia leaves, which is high in steviol glycosides, can be used as a high-potency sweetener. The current study proposes a high-performance thin layer chromatography (HPTLC) approach for estimating stevioside and rebaudioside that is rapid, verified, and repeatable. A collection of 32 chemotypes of Stevia rebaudiana were collected from 32 districts across nine Indian states. Stevioside and rebaudioside A content ranged between 1.43 - 5.88 % and 0.77 - 1.95 % respectively across 32 chemotypes of S. rebaudiana . Among all the studied samples, SrP1 chemotype was found to possess the highest quantity of stevioside (5.88 %) and rebaudioside A (1.95 %), followed by SrH11 (5.28 % Stev; 1.89 % Reb A) chemotypes obtained from Jalandhar, Punjab and Palampur, Himachal Pradesh respectively. Chemotype SrWb32 (1.43 % Stev; 0.77 % Reb A) collected from Bardhaman, West Bengal exhibited least amount of stevioside and rebaudioside A. The current fast, reproducible, and validated HPTLC method presents an efficacious toolkit to explore the quantitative variation in the stevioside and rebaudioside A contents in natural S. rebaudiana chemotypes. This methodology may be employed to screen high stevioside and rebaudioside A yielding elite genotypes for future propagation as well as commercialization of these highly potent sweeteners to deal with the ever-expanding demand for alternative yet natural sweeteners in food industries. • Thirty two populations or chemotypes of Stevia rebaudiana were analysed to detect steviol glycosides. • Chemotypes of the plant revealed altitudinal variation in steviosides and rebaudisides A content. • Elite chemotypes can further be used for propagation and commercial utilization.

Effects of NaCl on the interactions between neomethyl hesperidin dihydrochalcone and pork myofibrillar protein: Their relevance to gelation properties

Effects of sweetener neomethyl hesperidin dihydrochalcone (NHDC) on the gelation properties of myofibrillar protein (MP) at 0.2 M and 0.6 M NaCl were investigated. The results showed that addition of NHDC did not obviously change the cooking loss and strength of MP gels at 0.2 M NaCl. Whilst at 0.6 M NaCl, addition of high doses of NHDC (50–100 µM/g) remarkably increased cooking loss and decreased strength of MP gels. The expanded MP enhanced the interactions between NHDC and MP, leading to aggregation of MP as evidenced by the increasing particle size and the reducing solubility. The MP aggregates impeded hydrophobic interactions and disulfide bonds crosslinking in the gelation process, thereby damaged the gelation properties of MP at 0.6 M NaCl. This was supported by the poor network of MP gels observed by SEM. In the end, molecular docking elucidated the main types of interaction at molecular level, including hydrogen bonding and hydrophobicity. The results would provide guidance for NHDC as a potential sweetener in meat products.

Enhancing the thermostability of d-allulose 3-epimerase from Clostridium cellulolyticum H10 via directed evolution

d-allulose, the epimer at C-3 position of d-fructose, is a low-calorie functional rare sugar, which is regarded as one of the most potential sweeteners. At present, the main production method of d-allulose is epimerization of d-fructose by d-allulose 3-epimerase (DAE). However, industrial applications of DAE are still limited by its poor thermostability. Herein, directed evolution was applied to improve the thermostability of DAE from Clostridium cellulolyticum H10 (CcDAE). Two optimal mutants D281G and C289R, exhibiting 13.80-fold and 13.88-fold t1/2 values as that of wild type at 65 ℃, respectively, were obtained. To further enhance the thermostability, the triple mutant A107P/D281G/C289R was constructed after combination of mutants D281G, C289R, and previously identified thermostability-enhanced mutant A107P. The Tm and optimal temperature of triple mutant were increased by 14.39 ℃ and 5 ℃, respectively, compared to the wild type, meanwhile, the half-life of triple mutant was 58.85-fold as that of wild type at 65 ℃. Furthermore, the conversion rate of triple mutant was increased from 24.76% of wild type to 27.53% using 300 g/L d-fructose as substrate at 70 ℃. The effectiveness of directed evolution was verified and the triple mutant with enhanced thermostability had great application value in the large-scale production of d-allulose.

Effect of xylitol on the growth of Lactobacillus acidophilus for food and pharmaceutical applications / Efeito do xilitol no crescimento do Lactobacillus acidophilus em alimentos e aplicações farmacêuticas

The aim of this study was to compare the effect of different concentrations of xylitol on the Lactobacillus acidophilus (LA) growth from different origins: LA from a pharmaceutical supplement produced by Aché ® (LA1), LA lyophilized used in dairy fermented products produced by Sacco ® (LA2) and LA of manipulated pharmaceutical supplements of a local pharmacy of Cascavel-Paraná/Brazil (LA3). All of them were recommended to help the regulation of human intestinal flora. In MRS broth amounts of xylitol were added until final concentrations reached 3%, 8%, 12%, 15%, 18%, 25% and 40%. After sterilizing the medium, the standardized inoculum was added with subsequent incubation at 72 h in anaerobiosis. It was possible to conclude that xylitol influences the growth of LA and the higher concentrations of xylitol the lower growth of LA. LA3 growth 2x above than the other origins until 18% xylitol. This may favor the use of this strain for pharmaceutical preparations using xylitol. LA2 presented some advantages in relation to the pharmaceutical origin, since its growth in the presence of xylitol was faster, and this could indicate a possible greater amount of microorganisms in the intestinal tract in a short time. Over 12% were observed an inhibitory effect, by reducing the LA count below the recommended limit of 10 9 . This result is important, because as xylitol has the same sweetness potency of sucrose, it is believed that it may be used in different formulations until 12%, concentration commonly used as sweetener without significantly influencing the growth of Lactobacillus acidophilus .

New Glycosylated Dihydrochalcones Obtained by Biotransformation of 2'-Hydroxy-2-methylchalcone in Cultures of Entomopathogenic Filamentous Fungi.

Flavonoids, including chalcones, are more stable and bioavailable in the form of glycosylated and methylated derivatives. The combined chemical and biotechnological methods can be applied to obtain such compounds. In the present study, 2′-hydroxy-2-methylchalcone was synthesized and biotransformed in the cultures of entomopathogenic filamentous fungi Beauveria bassiana KCH J1.5, Isaria fumosorosea KCH J2 and Isaria farinosa KCH J2.6, which have been known for their extensive enzymatic system and ability to perform glycosylation of flavonoids. As a result, five new glycosylated dihydrochalcones were obtained. Biotransformation of 2′-hydroxy-2-methylchalcone by B. bassiana KCH J1.5 resulted in four glycosylated dihydrochalcones: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, 2′-hydroxy-2-hydroxymethyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside, and 2′,4-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. In the culture of I. fumosorosea KCH J2 only one product was formed—3-hydroxy-2-methyldihydrochalcone 2′-O-β-d-(4″-O-methyl)-glucopyranoside. Biotransformation performed by I. farinosa KCH J2.6 resulted in the formation of two products: 2′-hydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside and 2′,3-dihydroxy-2-methyldihydrochalcone 3′-O-β-d-(4″-O-methyl)-glucopyranoside. The structures of all obtained products were established based on the NMR spectroscopy. All products mentioned above may be used in further studies as potentially bioactive compounds with improved stability and bioavailability. These compounds can be considered as flavor enhancers and potential sweeteners.

Structural and anharmonic vibrational spectroscopic analysis of artificial sweetener alitame: A DFT study for molecular basis of sweet taste

Artificial sweeteners are synthetic and low-calorie food additives and used as sugar substitutes. Molecular basis of sweetness of them has not been fully defined and understood, yet. Alitame is among the high-intensity artificial sweeteners and has the 2000 times greater sweetness potency than that of sucrose. It is a dipeptide composed of L-aspartic acid and D-alanine with a terminal N-substituted tetra methylthietanyl-amine portion. The goal of this study was to determine alitame's molecular structure and its vibrational wavenumbers by means of quantum chemical computations and, to reveal whether there is a correlation between the sweetness of alitame and selected molecular descriptors, for the first time. Results demonstrated that a strong hydrogen bond of 1.702 Å was formed between aspartic portion backbone-side chain and C=O-OH moiety of alitame. Here, we suggest that the dihedral angles of −19.64° and 7.03° between two single NH groups and two adjacent C=O groups of alitame with respect to each other might be in association with the sweetness of alitame, for the first time. In addition, there is an inversely proportional relationship between the sweetness and the molecular shape index. In contrast, a directly proportional relationship was found between the sweetness and the total surface area. Understanding the molecular structure of such compounds and constructing a better molecular basis of sweetness may help to design further artificial sweeteners that will be important in particularly diabetes and obesity.

Searching for optimal low calorie sweetener blends in ternary & quaternary system

This study investigated the presence of sweetness synergism and sensory characteristics of ternary and quaternary low-calorie sweetener blends. The objective was to identify effective combinations showing sweetness synergism as well as sweetness properties similar to those of sucrose. Four types of bulk sweeteners (sucrose, allulose, tagatose, and erythritol) and potent sweeteners (sucralose and 3 rebaudiosides) were the samples of interest, and they were used to formulate 24 ternary and 47 quaternary mixtures. A descriptive analysis was applied to evaluate the sensory characteristics of these combinations. A 10% sucrose solution was included as a control when evaluating the sensory characteristics of all sweetener combination samples. Among the sweetener combinations, mixtures showing sweetness qualities similar to those of the sucrose control and those exhibiting sweetness synergism were identified. The results showed that including a larger number of combined sweeteners as well as a larger proportion of bulk sweeteners in the mixtures increased the likelihood of sweetness synergism and minimal off notes such as bitterness and astringency.

Relationships between the response of the sweet taste receptor, salivation toward sweeteners, and sweetness intensity.

Sweeteners are widely used in food products, and their sweetness potency is usually evaluated by comparing it with that of sucrose. This, however, has led to confusion as some sweeteners are evaluated based on their maximum value of sweet taste response, while others are evaluated by their threshold value. Here, we aimed to develop a novel nonverbal sweetness evaluation system through the sweet taste signal transduction by comparing the responses of the sweet taste receptor, salivation, taste intensity, and preference among six sweeteners. The hT1r2/hT1r3 sweet taste receptor responses represented the input signal of the sweet taste signal transduction, while salivation, sweet taste intensity, and participants' preferences represented the output signals by the gustatory–salivary reflex, primary gustatory cortex area, and the secondary gustatory cortex, respectively. Our results showed that the sweet taste receptor, sweet intensity, and salivary secretion responses were concentration‐dependent and expressed exponentially. Moreover, the results comparing coefficients showed 15–35 times more sensitivity between the response of hT1r2/hT1r3 and the salivation or the sweet taste intensity in non‐nutrient sweeteners. The preference graph curve was not exponential, suggesting that the sweetener preference was not related to the sweet taste receptor, salivation, or sweet taste intensity. These results may suggest that the sweet taste signal of the non‐nutritive sweeteners might be maintained by taste reception by hT1r2/hT1r3 to taste recognition in the primary gustatory area and that receptor responses and salivation could be used as indicators of sweetness intensity.

In-silico screening of database for finding potential sweet molecules: A combined data and structure based modeling approach

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.

Aldoxime Dehydratase Mutants as Improved Biocatalysts for a Sustainable Synthesis of Biorenewables-Based 2-Furonitrile

2-Furonitrile is an interesting nitrile product for the chemical industry due to its use as intermediate in the field of fine chemicals and pharmaceuticals or as a potential sweetener, as well as due to its access from biorenewables. As an alternative to current processes based on, e.g., the ammoxidation of furfural with ammonia as a gas phase reaction running at > 400 °C, we recently reported an enzymatic dehydration of 2-furfuryl aldoxime being obtained easily from furfural and hydroxylamine. However, improving the catalytic properties of the aldoxime dehydratase biocatalyst from Rhodococcus sp. YH3-3 (OxdYH3-3) in terms of activity and stability remained a challenge. In this contribution, the successful development of aldoxime dehydratase OxdYH3-3 mutants that were generated by directed evolution and its enhanced activity toward 2-furfuryl aldoxime is reported. The mutant OxdYH3-3 N266S showed an improved activity of up to six times higher than the wild type when utilizing a substrate concentration of 50–100 mM of 2-furfuryl aldoxime.

Improved expression of recombinant sweet-tasting brazzein using codon optimization and host change as new strategies

ABSTRACTThere is increased food industry attention to low-calorie natural sweeteners with good taste properties such as in plant-based sweet proteins. Brazzein is an attractive alternative to sucrose because of its intense sweetness, natural origin, and good stability at wide pH ranges and high temperature. In the present study, by using the minor form of brazzein as the basic sequence, the codon-optimized brazzein gene was designed based on appropriate GC content and preferred codon of E. coli. Then, the synthesized brazzein gene was cloned in pET28a vector and expressed in BL21(DE3) and SHuffle® T7 Express strains. Recombinant brazzein was expressed about 1.8 to 2.3 mg/L and 7.2 to 8.4 mg/L in BL21 (DE3) and SHuffle® T7 Express strain, respectively. Recombinant brazzein with His-tag lacked the sweetness. After the removal of the His-tag, it was shown that in addition to sweetness potency, the amount of brazzein proteins purified from SHuffle® T7 Express was higher than that from BL21. This improvement could be due to the better performance of SHuffle® T7 Express in the expression of the protein with high disulfide bridges and the effect of disulfide bonds on the sweetness of brazzein.

Effect of concentration range on the accuracy of measuring sweetness potencies of sweeteners

The main objective of the present study was to determine the effect of the concentration range of sweetener on the accuracy of sweetness potency, defined as the ratio of target sweetener and sucrose concentrations at equivalent sweetness intensity level (Wee, Tan, & Forde, 2018), measurement. Attempts were made to measure the sweetness potencies of two bulk sweeteners (powder allulose and liquefied allulose) and three intense sweeteners (sucralose, rebaudioside A, rebaudioside D) using a sucrose-sweetener combined (SSC) method. Three sets of sample combination were evaluated in three independent descriptive analysis testing sessions. One set of sweetener samples had a sucrose-equivalent concentration (SEC) range of 2–15%, wide range condition. The other two sample sets had narrower SEC ranges, of 1–9% for the narrow-range, low-concentration condition, and 8–16% for the narrow-range, high-concentration condition. All samples were evaluated by 10 trained panelists. Reference standards for sweetness intensities were provided during the testing sessions. Overall, the predicted sweetness potency measured over the wide concentration range was less accurate than that measured over the narrower range. Additionally, the results showed that the sweetness potencies were little affected by the concentration for bulk sweeteners, while the sweetness potencies changed dramatically for intense sweeteners. The SSC method was previously proposed for reducing the contextual bias caused by a range-frequency effect during sweetness intensity measurement. However, the present study has revealed that this method is not completely free from psychological biases and that the accuracy of measuring sweetness potency can be affected by the concentration range over which the panelist is evaluating. Thus, the concentration range of sample sets that are evaluated together should be determined carefully to ensure accurate measurement of sweetness.

E-Sweet: A Machine-Learning Based Platform for the Prediction of Sweetener and Its Relative Sweetness.

Artificial sweeteners (AS) can elicit the strong sweet sensation with the low or zero calorie, and are widely used to replace the nutritive sugar in the food and beverage industry. However, the safety issue of current AS is still controversial. Thus, it is imperative to develop more safe and potent AS. Due to the costly and laborious experimental-screening of AS, in-silico sweetener/sweetness prediction could provide a good avenue to identify the potential sweetener candidates before experiment. In this work, we curate the largest dataset of 530 sweeteners and 850 non-sweeteners, and collect the second largest dataset of 352 sweeteners with the relative sweetness (RS) from the literature. In light of these experimental datasets, we adopt five machine-learning methods and conformational-independent molecular fingerprints to derive the classification and regression models for the prediction of sweetener and its RS, respectively via the consensus strategy. Our best classification model achieves the 95% confidence intervals for the accuracy (0.91 ± 0.01), precision (0.90 ± 0.01), specificity (0.94 ± 0.01), sensitivity (0.86 ± 0.01), F1-score (0.88 ± 0.01), and NER (Non-error Rate: 0.90 ± 0.01) on the test set, which outperforms the model (NER = 0.85) of Rojas et al. in terms of NER, and our best regression model gives the 95% confidence intervals for the R2(test set) and ΔR2 [referring to |R2(test set)- R2(cross-validation)|] of 0.77 ± 0.01 and 0.03 ± 0.01, respectively, which is also better than the other works based on the conformation-independent 2D descriptors (e.g., 2D Dragon) according to R2(test set) and ΔR2. Our models are obtained by averaging over nineteen data-splitting schemes, and fully comply with the guidelines of Organization for Economic Cooperation and Development (OECD), which are not completely followed by the previous relevant works that are all on the basis of only one random data-splitting scheme for the cross-validation set and test set. Finally, we develop a user-friendly platform “e-Sweet” for the automatic prediction of sweetener and its corresponding RS. To our best knowledge, it is a first and free platform that can enable the experimental food scientists to exploit the current machine-learning methods to boost the discovery of more AS with the low or zero calorie content.

Physicochemical characterisation of oil palm (Elaeis guineensis) trunk syrup from the sap of different storage period as potential sweetener

Sap from the trunk of oil palm (Elaeis guineensis) was processed into syrup in this study. Physicochemical properties of syrups produced from the sap of freshly cut oil palm trunks (OPT0syrup) and sap of trunks stored for 60 days (OPT60syrup) at ambient temperature were compared to nipa palm syrup (Nsyrup), maple syrup (Msyrup), and two commercial glucose syrups (G1syrup and G2syrup). The total soluble solids for the syrups (OPT0sy, OPT60sy, Nsy, Msy, G1sy and G2sy) were in the range of 66 to 82 ˚Brix. The sugar analysis indicated that glucose was the main sugar for OPT0sy and OPT60sy as 367 and 300 mg/g, respectively, whereby sucrose was the foremost sugar for Nsy and Msy. The colour of the syrups was ranked from the darkest to the lightest; OPT60syrup > OPT0syrup > Msyrup > Nsyrup > G1syrup > G2syrup. OPT0syrup and OPT60syrup achieved reducing capacity of 825 and 886 mg GAE/100 g, respectively, significantly higher than other syrups. The free radical scavenging activities of OPT0syrup and OPT60syrup were 74% and 70%, respectively. In conclusion, the oil palm trunk syrup has similar physicochemical properties with the commercial syrups, and it has the potential to be an alternative to the commercial sweeteners with added nutritional benefits.

The Sweet Taste of Acarbose and Maltotriose: Relative Detection and Underlying Mechanism.

Although sweet-tasting saccharides possess similar molecular structures, their relative sweetness often varies to a considerable degree. Current understanding of saccharide structure/sweetness interrelationships is limited. Understanding how certain structural features of saccharides and/or saccharide analogs correlate to their relative sweetness can provide insight on the mechanisms underlying sweetness potency. Maltotriose is a short-chain glucose-based oligosaccharide, which we recently reported to elicit sweet taste. Acarbose, an α-glucosidase inhibitor, is a pseudo-saccharide that has an overall resemblance to a glucose-based oligosaccharide and thus may be viewed as a structural analog. During other studies, we recognized that acarbose can also elicit sweet taste. Here, we formally investigated the underlying taste detection mechanism of acarbose, while confirming our previous findings for maltotriose. We found that subjects could detect the sweet taste of acarbose and maltotriose in aqueous solutions but were not able to detect them in the presence of a sweet taste inhibitor lactisole. These findings support that both are ligands of the human sweet taste receptor, hT1R2/hT1R3. In a separate experiment, we measured the relative sweetness detection of acarbose, maltotriose, and other sweet-tasting mono- and disaccharides (glucose, fructose, maltose, and sucrose). Whereas maltotriose was found to have a similar discriminability profile to glucose and maltose, the discriminability of acarbose matched that of fructose at the concentrations tested (18, 32, and 56 mM). These findings are discussed in terms of how specific molecular features (e.g., degree of polymerization and monomer composition) may contribute to the relative sweetness of saccharides.