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Lynch B, Wang T, Vo T, Tafazoli S, Ryder J. Safety evaluation of oubli fruit sweet protein (brazzein) derived from Komagataella phaffii, intended for use as a sweetener in food and beverages. TOXICOLOGY RESEARCH AND APPLICATION 2023. [DOI: 10.1177/23978473231151258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Naturally sweet proteins have no glycemic effect and offer a fundamentally new approach to sweetness and health for individuals seeking to reduce their added sugar intake. However, unlike many commercial sweeteners, little research has been performed on the potential safety implications of adding these uniquely sweet proteins to food and beverages. In this study, a naturally sweet protein found in the West African Oubli plant ( Pentadiplandra brazzeana), referred to as Oubli fruit sweet protein or brazzein, was expressed in Komagataella phaffii (formerly Pichia pastoris) and produced via precision fermentation, and a safety and risk assessment was undertaken for its use as a sweetener in food and beverages. Potential consumption levels of brazzein were estimated to be 3 mg/kg body weight/day based on the National Health and Nutrition Examination Survey. The safety of brazzein derived from K. phaffii was evaluated through in silico allergenicity, in vitro genotoxicity (reverse mutation and mammalian micronucleus assays), and a 90-day dietary oral toxicity study in rats. There was no indication of allergenicity in the in silico analyses. Brazzein was non-genotoxic in the in vitro assays and showed no adverse effects in the 90-day oral toxicity study up to the highest dose tested, where the no-observed-adverse-effect level (NOAEL) was 978 and 985 mg/kg body weight/day in males and females, respectively. The totality of evidence in the in silico allergenicity, in vitro genotoxicity, and 90-day dietary toxicity studies demonstrates that brazzein derived from K. phaffii is considered safe for use as a sweetener in food and beverages.
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Affiliation(s)
| | | | - Trung Vo
- Intertek, Mississauga, ON, Canada
| | | | - Jason Ryder
- Oobli Inc, Davis, CA, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
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Altunayar-Unsalan C, Unsalan O. Structural and anharmonic vibrational spectroscopic analysis of artificial sweetener alitame: A DFT study for molecular basis of sweet taste. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.131157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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3
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Zhong H, Huang J, Shang S, Yuan B. Evolutionary insights into umami, sweet, and bitter taste receptors in amphibians. Ecol Evol 2021; 11:18011-18025. [PMID: 35003653 PMCID: PMC8717283 DOI: 10.1002/ece3.8398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/06/2021] [Accepted: 11/11/2021] [Indexed: 12/19/2022] Open
Abstract
Umami and sweet sensations provide animals with important dietary information for detecting and consuming nutrients, whereas bitter sensation helps animals avoid potentially toxic or harmful substances. Enormous progress has been made toward animal sweet/umami taste receptor (Tas1r) and bitter taste receptor (Tas2r). However, information about amphibians is mainly scarce. This study attempted to delineate the repertoire of Tas1r/Tas2r genes by searching for currently available genome sequences in 14 amphibian species. This study identified 16 Tas1r1, 9 Tas1r2, and 9 Tas1r3 genes to be intact and another 17 Tas1r genes to be pseudogenes or absent in the 14 amphibians. According to the functional prediction of Tas1r genes, two species have lost sweet sensation and seven species have lost both umami and sweet sensations. Anurans possessed a large number of intact Tas2rs, ranging from 39 to 178. In contrast, caecilians possessed a contractive bitter taste repertoire, ranging from 4 to 19. Phylogenetic and reconciling analysis revealed that the repertoire of amphibian Tas1rs and Tas2rs was shaped by massive gene duplications and losses. No correlation was found between feeding preferences and the evolution of Tas1rs in amphibians. However, the expansion of Tas2rs may help amphibians adapt to both aquatic and terrestrial habitats. Bitter detection may have played an important role in the evolutionary adaptation of vertebrates in the transition from water to land.
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Affiliation(s)
- Huaming Zhong
- College of Biology and FoodShangqiu Normal UniversityShangqiuChina
| | - Jie Huang
- College of Biology and FoodShangqiu Normal UniversityShangqiuChina
| | - Shuai Shang
- College of Biological and Environmental EngineeringBinzhou UniversityBinzhouChina
| | - Baodong Yuan
- College of Biology and FoodShangqiu Normal UniversityShangqiuChina
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Koyama S, Kondo K, Ueha R, Kashiwadani H, Heinbockel T. Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia. Int J Mol Sci 2021; 22:8912. [PMID: 34445619 PMCID: PMC8396277 DOI: 10.3390/ijms22168912] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.
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Affiliation(s)
- Sachiko Koyama
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Kenji Kondo
- Department of Otolaryngology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan;
| | - Rumi Ueha
- Department of Otolaryngology, Faculty of Medicine, The University of Tokyo, Tokyo 113-8655, Japan;
- Swallowing Center, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Hideki Kashiwadani
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan;
| | - Thomas Heinbockel
- Department of Anatomy, College of Medicine, Howard University, Washington, DC 20059, USA
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Delfi M, Emendato A, Temussi PA, Picone D. Striking Dependence of Protein Sweetness on Water Quality: The Role of the Ionic Strength. Front Mol Biosci 2021; 8:705102. [PMID: 34368232 PMCID: PMC8339437 DOI: 10.3389/fmolb.2021.705102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/30/2021] [Indexed: 11/16/2022] Open
Abstract
Sweet proteins are the sweetest natural molecules. This aspect prompted several proposals for their use as food additives, mainly because the amounts to be added to food would be very small and safe for people suffering from sucrose-linked diseases. During studies of sweet proteins as food additives we found that their sweetness is affected by water salinity, while there is no influence on protein’s structure. Parallel tasting of small size sweeteners revealed no influence of the water quality. This result is explained by the interference of ionic strength with the mechanism of action of sweet proteins and provides an experimental validation of the wedge model for the interaction of proteins with the sweet receptor.
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Affiliation(s)
- Masoud Delfi
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Alessandro Emendato
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Piero Andrea Temussi
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Naples, Italy.,UK Dementia Research Institute at King's College London, The Maurice Wohl Institute, London, United Kingdom
| | - Delia Picone
- Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Naples, Italy
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von Molitor E, Riedel K, Krohn M, Hafner M, Rudolf R, Cesetti T. Sweet Taste Is Complex: Signaling Cascades and Circuits Involved in Sweet Sensation. Front Hum Neurosci 2021; 15:667709. [PMID: 34239428 PMCID: PMC8258107 DOI: 10.3389/fnhum.2021.667709] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 05/20/2021] [Indexed: 12/13/2022] Open
Abstract
Sweetness is the preferred taste of humans and many animals, likely because sugars are a primary source of energy. In many mammals, sweet compounds are sensed in the tongue by the gustatory organ, the taste buds. Here, a group of taste bud cells expresses a canonical sweet taste receptor, whose activation induces Ca2+ rise, cell depolarization and ATP release to communicate with afferent gustatory nerves. The discovery of the sweet taste receptor, 20 years ago, was a milestone in the understanding of sweet signal transduction and is described here from a historical perspective. Our review briefly summarizes the major findings of the canonical sweet taste pathway, and then focuses on molecular details, about the related downstream signaling, that are still elusive or have been neglected. In this context, we discuss evidence supporting the existence of an alternative pathway, independent of the sweet taste receptor, to sense sugars and its proposed role in glucose homeostasis. Further, given that sweet taste receptor expression has been reported in many other organs, the physiological role of these extraoral receptors is addressed. Finally, and along these lines, we expand on the multiple direct and indirect effects of sugars on the brain. In summary, the review tries to stimulate a comprehensive understanding of how sweet compounds signal to the brain upon taste bud cells activation, and how this gustatory process is integrated with gastro-intestinal sugar sensing to create a hedonic and metabolic representation of sugars, which finally drives our behavior. Understanding of this is indeed a crucial step in developing new strategies to prevent obesity and associated diseases.
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Affiliation(s)
- Elena von Molitor
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | | | | | - Mathias Hafner
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
| | - Rüdiger Rudolf
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Tiziana Cesetti
- Institute of Molecular and Cell Biology, Hochschule Mannheim, Mannheim, Germany
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Hashimoto M, Nakagita T, Misaka T. Recent progress in the use of diaziridine-based sweetener derivatives to elucidate the chemoreception mechanism of the sweet taste receptor. RSC Adv 2021; 11:32236-32247. [PMID: 35495529 PMCID: PMC9041848 DOI: 10.1039/d1ra04831g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/21/2021] [Indexed: 11/21/2022] Open
Abstract
The review summarized recent progress for the elucidation of the chemoreception mechanism of sweet taste receptor–sweetener interactions with photoaffinity labeling.
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Affiliation(s)
- Makoto Hashimoto
- Division of Applied Science, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan
| | - Tomoya Nakagita
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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8
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Structural analysis of saccharin in aqueous solution by NMR and supramolecular interactions with α-, β-, γ-cyclodextrins. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Oruc G, Varnali T, Bekiroglu S. Hydroxy protons as structural probes to reveal hydrogen bonding properties of polyols in aqueous solution by NMR spectroscopy. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Zhang HX, Sun G, Gu JL, Du ZZ. New Sweet-Tasting Oleanane-Type Triterpenoid Saponins from "Tugancao" (Derris eriocarpa How). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:2357-2363. [PMID: 28238265 DOI: 10.1021/acs.jafc.7b00137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
With the aim to investigate the sweet-tasting compounds in Derris eriocarpa How (a substitute for licorice in "Zhuang" and "Dai" ethnopharmacy in Guangxi and Yunnan provinces of China) as well as to ascertain why the stem of D. eriocarpa can be used to substitute for licorice in the sweetness taste aspect, taste sensory-guided fractionation was conducted to isolate sweet constituents from the extract of D. eriocarpa. Four sweet-tasting triterpenoid saponins were obtained, including millettiasaponin A (1) and three new saponins named derrisaponins A-C (2-4). The sweetness potency was evaluated by a human sensory panel test. The sweetness intensities of compounds 1-4 were determined to be approximately 150, 80, 2, and 0.5 times relative to sucrose at the concentration of 1%, respectively, of which compounds 1 and 2, with a free carboxyl group at the C-30 position, showed more potent sweetness intensity. In addition, compounds 1 and 2 showed no acute toxic activity at doses of 250 and 400 mg/kg of body weight, respectively, assessed through caudal vein injection to ICR mice. The contents of the sweetest compounds in stems were analyzed quantitatively as 352.80 mg/kg for compound 1 and 1887.60 mg/kg for compound 2 performed by ultra-performance liquid chromatography-tandem mass spectrometry.
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Affiliation(s)
- Hong-Xia Zhang
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming, Yunnan 650201, People's Republic of China
| | - Guo Sun
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming, Yunnan 650201, People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Jian-Long Gu
- Yunnan Tobacco Quality Inspection & Supervision Station , Kunming, Yunnan 650106, People's Republic of China
| | - Zhi-Zhi Du
- Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming, Yunnan 650201, People's Republic of China
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11
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Gerwig GJ, Te Poele EM, Dijkhuizen L, Kamerling JP. Stevia Glycosides: Chemical and Enzymatic Modifications of Their Carbohydrate Moieties to Improve the Sweet-Tasting Quality. Adv Carbohydr Chem Biochem 2016; 73:1-72. [PMID: 27816105 DOI: 10.1016/bs.accb.2016.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Stevia glycosides, extracted from the leaves of the plant Stevia rebaudiana Bertoni, display an amazing high degree of sweetness. As processed plant products, they are considered as excellent bio-alternatives for sucrose and artificial sweeteners. Being noncaloric and having beneficial properties for human health, they are the subject of an increasing number of studies for applications in food and pharmacy. However, one of the main obstacles for the successful commercialization of Stevia sweeteners, especially in food, is their slight bitter aftertaste and astringency. These undesirable properties may be reduced or eliminated by modifying the carbohydrate moieties of the steviol glycosides. A promising procedure is to subject steviol glycosides to enzymatic glycosylation, thereby introducing additional monosaccharide residues into the molecules. Depending on the number and positions of the monosaccharide units, the taste quality and sweetness potency of the compounds will vary. Many studies have been performed already, and this review summarizes the structures of native steviol glycosides and the recent data of modifications of the carbohydrate moieties that have been published to provide an overview of the current progress.
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Affiliation(s)
- Gerrit J Gerwig
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| | - Evelien M Te Poele
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| | - Lubbert Dijkhuizen
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| | - Johannis P Kamerling
- Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
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12
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13
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Gal J. The Discovery of Stereoselectivity at Biological Receptors: Arnaldo Piutti and the Taste of the Asparagine Enantiomers-History and Analysis on the 125th Anniversary. Chirality 2012; 24:959-76. [DOI: 10.1002/chir.22071] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 04/12/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Joseph Gal
- Departments of Medicine and Pathology; University of Colorado School of Medicine; Aurora; Colorado
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14
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Dörrich S, Falgner S, Schweeberg S, Burschka C, Brodin P, Wissing BM, Basta B, Schell P, Bauer U, Tacke R. Silicon-Containing Dipeptidic Aspartame and Neotame Analogues. Organometallics 2012. [DOI: 10.1021/om300442e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steffen Dörrich
- Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
| | - Steffen Falgner
- Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
| | - Sarah Schweeberg
- Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
| | - Christian Burschka
- Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
| | - Peter Brodin
- AstraZeneca, R&D Mölndal, Pepparedsleden 1, S-43183 Mölndal, Sweden
| | | | - Babro Basta
- AstraZeneca, R&D Mölndal, Pepparedsleden 1, S-43183 Mölndal, Sweden
| | - Peter Schell
- AstraZeneca, R&D Mölndal, Pepparedsleden 1, S-43183 Mölndal, Sweden
| | - Udo Bauer
- AstraZeneca, R&D Mölndal, Pepparedsleden 1, S-43183 Mölndal, Sweden
| | - Reinhold Tacke
- Institut für Anorganische Chemie, Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
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15
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Fitch C, Keim KS. Position of the Academy of Nutrition and Dietetics: use of nutritive and nonnutritive sweeteners. J Acad Nutr Diet 2012; 112:739-58. [PMID: 22709780 DOI: 10.1016/j.jand.2012.03.009] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Indexed: 12/26/2022]
Abstract
It is the position of the Academy of Nutrition and Dietetics that consumers can safely enjoy a range of nutritive sweeteners and nonnutritive sweeteners (NNS) when consumed within an eating plan that is guided by current federal nutrition recommendations, such as the Dietary Guidelines for Americans and the Dietary Reference Intakes, as well as individual health goals and personal preference. A preference for sweet taste is innate and sweeteners can increase the pleasure of eating. Nutritive sweeteners contain carbohydrate and provide energy. They occur naturally in foods or may be added in food processing or by consumers before consumption. Higher intake of added sugars is associated with higher energy intake and lower diet quality, which can increase the risk for obesity, prediabetes, type 2 diabetes, and cardiovascular disease. On average, adults in the United States consume 14.6% of energy from added sugars. Polyols (also referred to as sugar alcohols) add sweetness with less energy and may reduce risk for dental caries. Foods containing polyols and/or no added sugars can, within food labeling guidelines, be labeled as sugar-free. NNS are those that sweeten with minimal or no carbohydrate or energy. They are regulated by the Food and Drug Administration as food additives or generally recognized as safe. The Food and Drug Administration approval process includes determination of probable intake, cumulative effect from all uses, and toxicology studies in animals. Seven NNS are approved for use in the United States: acesulfame K, aspartame, luo han guo fruit extract, neotame, saccharin, stevia, and sucralose. They have different functional properties that may affect perceived taste or use in different food applications. All NNS approved for use in the United States are determined to be safe.
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Affiliation(s)
- Cindy Fitch
- West Virginia University, Morgantown, WV, USA
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16
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Li X, Bachmanov AA, Maehashi K, Li W, Lim R, Brand JG, Beauchamp GK, Reed DR, Thai C, Floriano WB. Sweet taste receptor gene variation and aspartame taste in primates and other species. Chem Senses 2011; 36:453-75. [PMID: 21414996 DOI: 10.1093/chemse/bjq145] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Aspartame is a sweetener added to foods and beverages as a low-calorie sugar replacement. Unlike sugars, which are apparently perceived as sweet and desirable by a range of mammals, the ability to taste aspartame varies, with humans, apes, and Old World monkeys perceiving aspartame as sweet but not other primate species. To investigate whether the ability to perceive the sweetness of aspartame correlates with variations in the DNA sequence of the genes encoding sweet taste receptor proteins, T1R2 and T1R3, we sequenced these genes in 9 aspartame taster and nontaster primate species. We then compared these sequences with sequences of their orthologs in 4 other nontasters species. We identified 9 variant sites in the gene encoding T1R2 and 32 variant sites in the gene encoding T1R3 that distinguish aspartame tasters and nontasters. Molecular docking of aspartame to computer-generated models of the T1R2 + T1R3 receptor dimer suggests that species variation at a secondary, allosteric binding site in the T1R2 protein is the most likely origin of differences in perception of the sweetness of aspartame. These results identified a previously unknown site of aspartame interaction with the sweet receptor and suggest that the ability to taste aspartame might have developed during evolution to exploit a specialized food niche.
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Affiliation(s)
- Xia Li
- Monell Chemical Senses Center, Philadelphia, PA 19104, USA
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17
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DuBois GE. Validity of early indirect models of taste active sites and advances in new taste technologies enabled by improved models. FLAVOUR FRAG J 2011. [DOI: 10.1002/ffj.2042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Grant E DuBois
- Research and Technologies Department; The Coca-Cola Company; Atlanta; GA 30313; USA
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18
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Behrens M, Meyerhof W, Hellfritsch C, Hofmann T. Moleküle und biologische Mechanismen des Süß- und Umamigeschmacks. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201002094] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Behrens M, Meyerhof W, Hellfritsch C, Hofmann T. Sweet and Umami Taste: Natural Products, Their Chemosensory Targets, and Beyond. Angew Chem Int Ed Engl 2011; 50:2220-42. [DOI: 10.1002/anie.201002094] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Indexed: 11/11/2022]
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20
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Abstract
A greater understanding of the molecular mechanisms of sweet taste has profound significance for the food industry as well as for consumers. Understanding the mechanism by which sweet taste is elicited by saccharides, peptides, and proteins will assist science and industry in their search for sweet substances with fewer negative health effects. The original AH-B theories have been supplanted by detailed structural models. Recent identification of the human sweet receptor as a dimeric G-protein coupled receptor comprising T1R2 and T1R3 subunits has greatly increased the understanding of the mechanisms involved in sweet molecule binding and sweet taste transduction. This review discusses early theories of the sweet receptor, recent research of sweetener chemoreception of nonprotein and protein ligands, homology modeling, the transduction pathway, the possibility of the sweet receptor functioning allosterically, as well as the implications of allelic variation.
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Affiliation(s)
- B Meyers
- NutraSweet Co., Chicago, IL 60654, USA
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21
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Kellett GL, Brot-Laroche E, Mace OJ, Leturque A. Sugar absorption in the intestine: the role of GLUT2. Annu Rev Nutr 2008; 28:35-54. [PMID: 18393659 DOI: 10.1146/annurev.nutr.28.061807.155518] [Citation(s) in RCA: 325] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Intestinal glucose absorption comprises two components. One is classical active absorption mediated by the Na+/glucose cotransporter. The other is a diffusive component, formerly attributed to paracellular flow. Recent evidence, however, indicates that the diffusive component is mediated by the transient insertion of glucose transporter type 2 (GLUT2) into the apical membrane. This apical GLUT2 pathway of intestinal sugar absorption is present in species from insect to human, providing a major route at high sugar concentrations. The pathway is regulated by rapid trafficking of GLUT2 to the apical membrane induced by glucose during assimilation of a meal. Apical GLUT2 is therefore a target for multiple short-term and long-term nutrient-sensing mechanisms. These include regulation by a newly recognized pathway of calcium absorption through the nonclassical neuroendocrine l-type channel Cav1.3 operating during digestion, activation of intestinal sweet taste receptors by natural sugars and artificial sweeteners, paracrine and endocrine hormones, especially insulin and GLP-2, and stress. Permanent apical GLUT2, resulting in increased sugar absorption, is a characteristic of experimental diabetes and of insulin-resistant states induced by fructose and fat. The nutritional consequences of apical and basolateral GLUT2 regulation are discussed in the context of Western diet, processed foods containing artificial sweeteners, obesity, and diabetes.
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Affiliation(s)
- George L Kellett
- Department of Biology (Area 3), The University of York, York YO10 5YW, United Kingdom.
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Tanrikulu Y, Schneider G. Pseudoreceptor models in drug design: bridging ligand- and receptor-based virtual screening. Nat Rev Drug Discov 2008; 7:667-77. [DOI: 10.1038/nrd2615] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gray JC, Habtemariam A, Winnig M, Meyerhof W, Sadler PJ. Sweetening ruthenium and osmium: organometallic arene complexes containing aspartame. J Biol Inorg Chem 2008; 13:1111-20. [PMID: 18553111 DOI: 10.1007/s00775-008-0396-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 05/25/2008] [Indexed: 11/27/2022]
Abstract
The novel organometallic sandwich complexes [(eta(6)-p-cymene)Ru(eta(6)-aspartame)](OTf)(2) (1) (OTf = trifluoromethanesulfonate) and [(eta(6)-p-cymene)Os(eta(6)-aspartame)](OTf)(2) (2) incorporating the artificial sweetener aspartame have been synthesised and characterised. A number of properties of aspartame were found to be altered on binding to either metal. The pK(a) values of both the carboxyl and the amino groups of aspartame are lowered by between 0.35 and 0.57 pH units, causing partial deprotonation of the amino group at pH 7.4 (physiological pH). The rate of degradation of aspartame to 3,6-dioxo-5-phenylmethylpiperazine acetic acid (diketopiperazine) increased over threefold from 0.12 to 0.36 h(-1) for 1, and to 0.43 h(-1) for 2. Furthermore, the reduction potential of the ligand shifted from -1.133 to -0.619 V for 2. For the ruthenium complex 1 the process occurred in two steps, the first (at -0.38 V) within a biologically accessible range. This facilitates reactions with biological reductants such as ascorbate. Binding to and activation of the sweet taste receptor was not observed for these metal complexes up to concentrations of 1 mM. The factors which affect the ability of metal-bound aspartame to interact with the receptor site are discussed.
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Affiliation(s)
- Jennifer C Gray
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, UK
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Teixeira SCM, Blakeley MP, Leal RMF, Mitchell EP, Forsyth VT. A preliminary neutron crystallographic study of thaumatin. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:378-81. [PMID: 18453706 PMCID: PMC2376403 DOI: 10.1107/s1744309108008294] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Accepted: 03/26/2008] [Indexed: 11/10/2022]
Abstract
A preliminary neutron crystallographic study of the sweet protein thaumatin is presented. Large hydrogenated crystals were prepared in deuterated crystallization buffer using the gel-acupuncture method. Data were collected to a resolution of 2 A on the LADI-III diffractometer at the Institut Laue Langevin (ILL). The results demonstrate the feasibility of a full neutron crystallographic analysis of this structure aimed at providing relevant information on the location of H atoms, the distribution of charge on the protein surface and localized water in the structure. This information will be of interest for understanding the specificity of thaumatin-receptor interactions and will contribute to further understanding of the molecular mechanisms underlying the perception of taste.
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Affiliation(s)
- Susana C. M. Teixeira
- ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble, France
- Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
- EPSAM and ISTM, Keele University, Staffordshire ST5 5BG, England
| | | | - Ricardo M. F. Leal
- ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble, France
- Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
- EPSAM and ISTM, Keele University, Staffordshire ST5 5BG, England
- ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble, France
| | - Edward P. Mitchell
- EPSAM and ISTM, Keele University, Staffordshire ST5 5BG, England
- ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble, France
| | - V. Trevor Forsyth
- ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble, France
- Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
- EPSAM and ISTM, Keele University, Staffordshire ST5 5BG, England
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Roper SD. Signal transduction and information processing in mammalian taste buds. Pflugers Arch 2007; 454:759-76. [PMID: 17468883 PMCID: PMC3723147 DOI: 10.1007/s00424-007-0247-x] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2006] [Accepted: 01/04/2007] [Indexed: 10/23/2022]
Abstract
The molecular machinery for chemosensory transduction in taste buds has received considerable attention within the last decade. Consequently, we now know a great deal about sweet, bitter, and umami taste mechanisms and are gaining ground rapidly on salty and sour transduction. Sweet, bitter, and umami tastes are transduced by G-protein-coupled receptors. Salty taste may be transduced by epithelial Na channels similar to those found in renal tissues. Sour transduction appears to be initiated by intracellular acidification acting on acid-sensitive membrane proteins. Once a taste signal is generated in a taste cell, the subsequent steps involve secretion of neurotransmitters, including ATP and serotonin. It is now recognized that the cells responding to sweet, bitter, and umami taste stimuli do not possess synapses and instead secrete the neurotransmitter ATP via a novel mechanism not involving conventional vesicular exocytosis. ATP is believed to excite primary sensory afferent fibers that convey gustatory signals to the brain. In contrast, taste cells that do have synapses release serotonin in response to gustatory stimulation. The postsynaptic targets of serotonin have not yet been identified. Finally, ATP secreted from receptor cells also acts on neighboring taste cells to stimulate their release of serotonin. This suggests that there is important information processing and signal coding taking place in the mammalian taste bud after gustatory stimulation.
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Affiliation(s)
- Stephen D Roper
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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26
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Roper SD. Signal transduction and information processing in mammalian taste buds. PFLUGERS ARCHIV : EUROPEAN JOURNAL OF PHYSIOLOGY 2007. [PMID: 17468883 DOI: 10.1007/s00424‐007‐0247‐x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The molecular machinery for chemosensory transduction in taste buds has received considerable attention within the last decade. Consequently, we now know a great deal about sweet, bitter, and umami taste mechanisms and are gaining ground rapidly on salty and sour transduction. Sweet, bitter, and umami tastes are transduced by G-protein-coupled receptors. Salty taste may be transduced by epithelial Na channels similar to those found in renal tissues. Sour transduction appears to be initiated by intracellular acidification acting on acid-sensitive membrane proteins. Once a taste signal is generated in a taste cell, the subsequent steps involve secretion of neurotransmitters, including ATP and serotonin. It is now recognized that the cells responding to sweet, bitter, and umami taste stimuli do not possess synapses and instead secrete the neurotransmitter ATP via a novel mechanism not involving conventional vesicular exocytosis. ATP is believed to excite primary sensory afferent fibers that convey gustatory signals to the brain. In contrast, taste cells that do have synapses release serotonin in response to gustatory stimulation. The postsynaptic targets of serotonin have not yet been identified. Finally, ATP secreted from receptor cells also acts on neighboring taste cells to stimulate their release of serotonin. This suggests that there is important information processing and signal coding taking place in the mammalian taste bud after gustatory stimulation.
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Affiliation(s)
- Stephen D Roper
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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