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Kim Y, Lee S, Jin M, Choi YA, Choi JK, Kwon TK, Khang D, Kim SH. Aspalathin, a Primary Rooibos Flavonoid, Alleviates Mast Cell-Mediated Allergic Inflammation by the Inhibition of FcεRI Signaling Pathway. Inflammation 2024:10.1007/s10753-024-02034-1. [PMID: 38777857 DOI: 10.1007/s10753-024-02034-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/25/2024]
Abstract
Mast cells are primary cells initiating allergic inflammation by the release of various allergic mediators, such as histamine and pro-inflammatory cytokines. Aspalathin (ASP) is the predominant flavonoid found exclusively in rooibos, an herb that has been traditionally used in allergy relief therapy. In the present study, we investigated the beneficial effects of ASP on mast cell-mediated allergic inflammation. For in vivo study, two well-known mast cell-mediated local and systemic allergic inflammation mouse models were used: passive cutaneous anaphylaxis (PCA) and active systemic anaphylaxis mouse models (ASA). Oral administration of ASP dose-dependently suppressed immunoglobulin (Ig)E-mediated PCA responses evidenced by Evans blue extravasation, ear thickening, and mast cell degranulation. ASP also significantly mitigated ovalbumin-induced ASA responses, including hypothermia, histamine secretion, and the production of IgE and interleukin-4. Notably, ASP was more effective in suppressing allergic inflammation than nothofagin, another prominent flavonoid known as an anti-allergic component of rooibos. The regulatory mechanism of mast cell activation by ASP was clarified using mast cell line and primary cultured mast cells (RBL-2H3 and mouse bone marrow-derived mast cells). ASP reduced IgE-stimulated mast cells degranulation and intracellular calcium influx by the inhibition of FcεRI signaling pathway (Lyn, Fyn, and Syk). Moreover, ASP reduced pro-inflammatory cytokine expressions by inhibiting two major transcription factors, nuclear factor of activated T cells and nuclear factor-κB. Collectively, we proposed that ASP could be a potential therapeutic candidate for the treatment of mast cell-mediated allergic inflammatory diseases.
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Affiliation(s)
- Yeyoung Kim
- Department of Pharmacology, School of Medicine, CMRI, Kyungpook National University, Daegu, 41944, Republic of Korea
| | - Soyoung Lee
- Immunoregulatory Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 56212, Republic of Korea
| | - Meiling Jin
- Department of Pharmacology, School of Medicine, Yanbian National University, Yanji, 133001, China
| | - Young-Ae Choi
- Department of Pharmacology, School of Medicine, CMRI, Kyungpook National University, Daegu, 41944, Republic of Korea
| | - Jin Kyeong Choi
- Department of Immunology, Jeonbuk National University Medical School, Jeonju, 54896, Republic of Korea
| | - Taeg Kyu Kwon
- Department of Immunology, School of Medicine, Keimyung University, Daegu, 42601, Republic of Korea
| | - Dongwoo Khang
- Department of Physiology, School of Medicine, Gachon University, Incheon, 21999, Republic of Korea.
| | - Sang-Hyun Kim
- Department of Pharmacology, School of Medicine, CMRI, Kyungpook National University, Daegu, 41944, Republic of Korea.
- Department of Physiology, School of Medicine, Gachon University, Incheon, 21999, Republic of Korea.
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de Beer D, Beelders T, Human C, Joubert E. Assessment of the stability of compounds belonging to neglected phenolic classes and flavonoid sub-classes using reaction kinetic modeling. Crit Rev Food Sci Nutr 2023; 63:11802-11829. [PMID: 35833472 DOI: 10.1080/10408398.2022.2096561] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Phenolic compounds are known to degrade and/or undergo changes during food production and storage. Reaction kinetic modeling is generally used to define kinetic parameters of a food system and predict changes during thermal processing and storage. Data for phenolic acids and flavonoids, such as anthocyanins and flavan-3-ols, have been reviewed in detail, but the flavonoid sub-classes, dihydrochalcones and flavanones, have been mostly neglected. Other neglected phenolic classes are xanthones and benzophenones. The stability of these types of compounds is important as they are present in fruits and exposed to heat when processed into juice and jam. Other sources of the compounds are herbal teas, which are also subjected to thermal processing, either during the primary processing of the plant material, or the production of extracts for use as food ingredients. The theoretical background is given to understand the review of literature on these classes/sub-classes. Results of research on kinetic modeling are discussed in detail, while research on compound stability without the application of reaction kinetic modeling is briefly mentioned to provide context. The studies discussed included those focusing on heating during the processing and storage of model solutions, liquid foods, plant material, dried extracts, and extracts formulated with other food ingredients.
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Affiliation(s)
- Dalene de Beer
- Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Stellenbosch, South Africa
- Department of Food Science, Stellenbosch University, Stellenbosch, South Africa
| | - Theresa Beelders
- Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Stellenbosch, South Africa
- Department of Food Science, Stellenbosch University, Stellenbosch, South Africa
| | - Chantelle Human
- Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Stellenbosch, South Africa
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Stellenbosch, South Africa
- Department of Food Science, Stellenbosch University, Stellenbosch, South Africa
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de Beer D, Human C, van der Rijst M, Joubert E. Reaction kinetics of aspalathin degradation and flavanone isomer formation in aqueous model solutions: Effect of temperature, pH and metal chelators. Food Res Int 2023; 172:113188. [PMID: 37689940 DOI: 10.1016/j.foodres.2023.113188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/19/2023] [Accepted: 06/27/2023] [Indexed: 09/11/2023]
Abstract
The poor stability of aspalathin in aqueous solutions is a major challenge in delivering a shelf-stable ready-to-drink (RTD) green rooibos iced tea. The kinetics of aspalathin degradation and the formation of eriodictyol glucoside isomers [(S/R)-6-β-D-glucopyranosyleriodictyol and (S/R)-8-β-D-glucopyranosyleriodictyol] in aqueous buffers were modeled to understand and predict aspalathin losses during heat processing. The effects of temperature and pH on the rate constants of aspalathin degradation and eriodictyol glucoside isomer formation were determined in a 0.1 M phosphate buffer with 5.7 mM citric acid. The zero-order model best described the reaction kinetics of aspalathin degradation and eriodictyol glucoside isomer formation. Increasing the temperature and pH increased the reaction rate constants. The activation energies of the reactions were much lower at pH 6 than at pH 4, indicating that pH affected the temperature dependence of the reactions. The 8-C-glucosyl eriodictyol derivatives (RE8G and SE8G) formed at much lower rates than the 6-C-glucosyl eriodictyol derivatives (RE6G and SE6G). The metal chelators, citric acid, citrate and EDTA, drastically reduced the reaction rate constants, indicating the catalytic role of metal ions in aspalathin autoxidation. The results of the study could assist manufacturers to improve the shelf life of rooibos RTD beverages by changing the formulation and adjusting heat processing conditions.
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Affiliation(s)
- Dalene de Beer
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
| | - Chantelle Human
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
| | - Marieta van der Rijst
- Biometry Unit, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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Sae-leaw T, Aluko RE, Chantakun K, Benjakul S. Physicochemical, Antioxidant and Sensory Properties of Ready-to-drink Chrysanthemum Tea Fortified with Hydrolyzed Collagen from Salmon Scale Ossein. JOURNAL OF AQUATIC FOOD PRODUCT TECHNOLOGY 2021. [DOI: 10.1080/10498850.2021.1974632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Thanasak Sae-leaw
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand
| | - Rotimi E. Aluko
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kasidate Chantakun
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand
| | - Soottawat Benjakul
- International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Songkhla, Thailand
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Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder-Assessment of Physical, Chemical, and Sensory Properties. Molecules 2021; 26:molecules26175260. [PMID: 34500693 PMCID: PMC8433966 DOI: 10.3390/molecules26175260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
Green rooibos extract (GRE), shown to improve hyperglycemia and HDL/LDL blood cholesterol, has potential as a nutraceutical beverage ingredient. The main bioactive compound of the extract is aspalathin, a C-glucosyl dihydrochalcone. The study aimed to determine the effect of common iced tea ingredients (citric acid, ascorbic acid, and xylitol) on the stability of GRE, microencapsulated with inulin for production of a powdered beverage. The stability of the powder mixtures stored in semi-permeable (5 months) and impermeable (12 months) single-serve packaging at 30 °C and 40 °C/65% relative humidity was assessed. More pronounced clumping and darkening of the powders, in combination with higher first order reaction rate constants for dihydrochalcone degradation, indicated the negative effect of higher storage temperature and an increase in moisture content when stored in the semi-permeable packaging. These changes were further increased by the addition of crystalline ingredients, especially citric acid monohydrate. The sensory profile of the powders (reconstituted to beverage strength iced tea solutions) changed with storage from a predominant green-vegetal aroma to a fruity-sweet aroma, especially when stored at 40 °C/65% RH in the semi-permeable packaging. The change in the sensory profile of the powder mixtures could be attributed to a decrease in volatile compounds such as 2-hexenal, (Z)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E,Z)-2,6-nonadienal and (E)-2-decenal associated with "green-like" aromas, rather than an increase in fruity and sweet aroma-impact compounds. Green rooibos extract powders would require storage at temperatures ≤ 30 °C and protection against moisture uptake to be chemically and physically shelf-stable and maintain their sensory profiles.
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Sun CC, Li Y, Yin ZP, Zhang QF. Physicochemical properties of dihydromyricetin and the effects of ascorbic acid on its stability and bioavailability. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2021; 101:3862-3869. [PMID: 33336364 DOI: 10.1002/jsfa.11022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 12/09/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactive effects. However, the physicochemical properties of DMY related to its bioavailability, especially its stability, are unclear. RESULTS The effects of pH, temperature, metal ions and ascorbic acid (AA) on the stability of DMY were studied using high-performance liquid chromatography (HPLC). The bioavailability of DMY in the presence and absence of AA was compared. Dihydromyricetin was unstable in weak alkaline solutions, and the degradation was significantly accelerated in the presence of Cu2+ and Fe3+ . The degradation process followed the first-order kinetic model. The degradation rate constant (k) increased with increasing pH and temperature. The remaining DMY was only 49% of its initial concnentration after 4 h in simulated intestinal fluid (SIF) at 37 °C. However, by supplementing with AA, the degradation of DMY was rarely occured within 6 h. The solubility of DMY at pH 3-5 was about 750 μg mL-1 , slightly increasing to 853 μg mL-1 at pH 6. Pharmacokinetic studies showed that the bioavailability of DMY increased from 0.122% to 0.341% by supplementing with AA (10% of DMY). CONCLUSION The degradation of DMY is one reason for its poor bioavailability. The presence of AA could significantly improve the stability of DMY, and further improve its bioavailability in rats. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Cui-Cui Sun
- Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China
| | - Ying Li
- Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China
| | - Zhong-Ping Yin
- Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China
| | - Qing-Feng Zhang
- Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, China
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Human C, Danton O, De Beer D, Maruyama T, Alexander L, Malherbe C, Hamburger M, Joubert E. Identification of a novel di-C-glycosyl dihydrochalcone and the thermal stability of polyphenols in model ready-to-drink beverage solutions with Cyclopia subternata extract as functional ingredient. Food Chem 2021; 351:129273. [PMID: 33662907 DOI: 10.1016/j.foodchem.2021.129273] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/29/2021] [Accepted: 01/30/2021] [Indexed: 11/15/2022]
Abstract
Heat processing of ready-to-drink beverages is required to ensure a microbiologically safe product, however, this can result in the loss of bioactive compounds responsible for functionality. The objective of this study was to establish the thermal stability of a novel dihydrochalcone, 3',5'-di-β-d-glucopyranosyl-3-hydroxyphloretin (2), 3',5'-di-β-d-glucopyranosylphloretin (3) and other Cyclopia subternata phenolic compounds, in model solutions with or without citric acid and ascorbic acid. The solutions were heated at 93, 121 and 135 °C, relevant to pasteurisation, commercial sterilisation and ultra-high temperature (UHT) pasteurisation, respectively. For most compounds, the acids decreased the second order reaction rate constants, up to 27 times. Compound 2 (46.29 ± 0.53 (g/100 g)-1 h-1), and to a lesser extent compound 3 (5.94 ± 0.01 (g/100 g)-1 h-1) were the most thermo-unstable compounds when treated at 135 °C without added acids. Even though differential effects were observed for compounds at different temperatures and formulations, overall, the phenolic compounds were most stable under UHT pasteurisation conditions.
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Affiliation(s)
- Chantelle Human
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
| | - Ombeline Danton
- Pharmaceutical Biology, Pharmacenter, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Dalene De Beer
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch), 7600, South Africa
| | - Takuma Maruyama
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Lara Alexander
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch), 7600, South Africa
| | - Christiaan Malherbe
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
| | - Matthias Hamburger
- Pharmaceutical Biology, Pharmacenter, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch), 7600, South Africa.
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Alaşalvar H, Çam M. Ready to drink iced teas from microencapsulated spearmint (Mentha spicata L.) and peppermint (Mentha piperita L.) extracts: physicochemical, bioactive and sensory characterization. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2020. [DOI: 10.1007/s11694-020-00386-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Human C, De Beer D, Van Der Rijst M, Aucamp M, Joubert E. Electrospraying as a suitable method for nanoencapsulation of the hydrophilic bioactive dihydrochalcone, aspalathin. Food Chem 2018; 276:467-474. [PMID: 30409621 DOI: 10.1016/j.foodchem.2018.10.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/21/2018] [Accepted: 10/03/2018] [Indexed: 12/11/2022]
Abstract
The bioactive hydrophilic dihydrochalcone, aspalathin, has poor stability and bioavailability hampering its use in functional food ingredients with standardised aspalathin content. The aim of the study was to produce nanoparticles with controlled release to overcome these obstacles. Nanoencapsulation was investigated using both natural (chitosan and lecithin) and synthetic (poly(lactide-co-glycolide) and Eudragit S100® (ES100)) polymers by suitable conventional methods and electrospraying for all polymers. All polymer-method combinations produced particles smaller than 1.1 µm. Electrospraying produced more favourable results than conventional methods for the synthetic polymers, resulting in spherical particles with higher (p < 0.05) encapsulation efficiencies (>50%) and loading capacities (>10%). Opposite trends were observed for natural polymers. An in vitro release study revealed biphasic aspalathin release profiles at pH 7.4 with ES100 electrosprayed nanoparticles having the slowest (p < 0.05) release rate (1.67 h-1). Overall, ES100 electrosprayed nanoparticles showed the most favourable combination of parameters.
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Affiliation(s)
- Chantelle Human
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (Infruitec-Nietvoorbij), Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7600, South Africa
| | - Dalene De Beer
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (Infruitec-Nietvoorbij), Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7600, South Africa.
| | - Marieta Van Der Rijst
- Biometry Unit, Agricultural Research Council, Private Bag X5026, Stellenbosch 7599, South Africa
| | - Marique Aucamp
- School of Pharmacy, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (Infruitec-Nietvoorbij), Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7600, South Africa
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Miller N, De Beer D, Aucamp M, Malherbe CJ, Joubert E. Inulin as microencapsulating agent improves physicochemical properties of spray-dried aspalathin-rich green rooibos (Aspalathus linearis) extract with α-glucosidase inhibitory activity. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.07.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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de Beer D, Pauck CE, Aucamp M, Liebenberg W, Stieger N, van der Rijst M, Joubert E. Phenolic and physicochemical stability of a functional beverage powder mixture during storage: effect of the microencapsulant inulin and food ingredients. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:2925-2934. [PMID: 29168179 DOI: 10.1002/jsfa.8787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/06/2017] [Accepted: 11/18/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The need for a convenience herbal iced tea product with reduced kilojoules merited investigation of the shelf-life of powder mixtures containing a green Cyclopia subternata Vogel (honeybush) extract with proven blood glucose-lowering activity and alternative sweetener mixture. RESULTS Prior to long-term storage testing, the wettability of powder mixtures containing food ingredients and the compatibility of their components were confirmed using the static sessile drop method and isothermal microcalorimetry, respectively. The powders packed in semi-sealed containers remained stable during storage at 25 °C/60% relative humidity (RH) for 6 months, except for small losses of specific phenolic compounds, namely mangiferin, isomangiferin, 3-β-d-glucopyranosyliriflophenone, vicenin-2 and 3',5'-di-β-d-glucopyranosylphloretin, especially when both citric acid and ascorbic acid were present. These acids drastically increased the degradation of phenolic compounds under accelerated storage conditions (40 °C/75% RH). Accelerated storage also caused changes in the appearance of powders and the colour of the reconstituted beverage solutions. Increased moisture content and aw of the powders, as well as moisture released due to dehydration of citric acid monohydrate, contributed to these changes. CONCLUSION A low-kilojoule honeybush iced tea powder mixture will retain its functional phenolic compounds and physicochemical properties during shelf-life storage at 25 °C for 6 months. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Dalene de Beer
- Plant Bioactives Group, Post-Harvest and Agro-processing Technologies, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch, South Africa
- Department of Food Science, Stellenbosch University, Matieland, Stellenbosch, South Africa
| | - Claire E Pauck
- Department of Food Science, Stellenbosch University, Matieland, Stellenbosch, South Africa
| | - Marique Aucamp
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | - Wilna Liebenberg
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | - Nicole Stieger
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | - Marieta van der Rijst
- Biometry Unit, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch, South Africa
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest and Agro-processing Technologies, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch, South Africa
- Department of Food Science, Stellenbosch University, Matieland, Stellenbosch, South Africa
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Han Z, Achilonu MC, Kendrekar PS, Joubert E, Ferreira D, Bonnet SL, van der Westhuizen JH. Concise and scalable synthesis of aspalathin, a powerful plasma sugar-lowering natural product. JOURNAL OF NATURAL PRODUCTS 2014; 77:583-588. [PMID: 24354397 DOI: 10.1021/np4008443] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Aspalathin (1), a dihydrochalcone C-glucoside, exhibits powerful plasma sugar-lowering properties and thus potentially could be used to treat diabetes. Small quantities occur in rooibos tea, manufactured via fermentation of the leaves of Aspalathus linearis, hence necessitating the need for an efficient and concise synthesis. Efforts to synthesize aspalathin (1) via coupling of a glucose donor to the nucleophilic phloroglucinol ring of the dihydrochalcone moiety have invariably failed, presumably because of ring deactivation by the electron-withdrawing carbonyl group. Reduction of the carbonyl group of a chalcone (15) and coupling of the resulting 1,3-diarylpropane (16) to tetra-O-benzyl-β-D-glucopyranose afforded the C-glucosyl-1,3-diarylpropane (17). Regiospecific benzylic oxidation regenerated the carbonyl group and afforded the per-O-methylaspalathin (1a) quantitatively. This method was not successful with the per-O-benzyl-protected dihydrochalcone. However, the nucleophilicity of the phenolic hydroxy groups of the dihydrochalcone or its acetophenone precursor is not diminished by the carbonyl group. Thus, glucosylation of the di-O-benzylacetophenone (5c) at -40 °C afforded the α-O-glucoside (19) in 86% yield. Raising the temperature allowed facile BF3-catalyzed rearrangement to the β-C-glucoside (6b), which upon hydrogenation, afforded aspalathin (1) in 80% overall yield [based on the usage of di-O-benzylphloroacetophenone (5c) and tetra-O-benzyl-1α-fluoro-β-D-glucose (2e)].
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Affiliation(s)
- Ze Han
- Department of Chemistry, University of the Free State , Nelson Mandela Avenue, Bloemfontein, 9301, South Africa
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de Beer D, Joubert E, Viljoen M, Manley M. Enhancing aspalathin stability in rooibos (Aspalathus linearis) ready-to-drink iced teas during storage: the role of nano-emulsification and beverage ingredients, citric and ascorbic acids. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2012; 92:274-82. [PMID: 21780136 DOI: 10.1002/jsfa.4571] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/17/2011] [Accepted: 06/19/2011] [Indexed: 05/22/2023]
Abstract
BACKGROUND The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready-to-drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin-enriched green rooibos extract (GR) and aspalathin-enriched green rooibos extract ascorbic acid solubilisate (GR-solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS Storage of iced tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR iced tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso-orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR iced tea formulations. Improved stability of aspalathin was noted in iced tea containing GR-solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos iced teas. CONCLUSION Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix.
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Affiliation(s)
- Dalene de Beer
- Agricultural Research Council (Infruitec-Nietvoorbij Institute), Post-Harvest and Wine Technology Division, Private Bag X5026, Stellenbosch 7599, South Africa.
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