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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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Human C, De Beer D, Bowles S, Joubert E. Effect of electrospraying conditions on the properties of aspalathin‐Eudragit S100 nanoparticles and assessment of orogastrointestinal stability and membrane permeability. FOOD FRONTIERS 2022. [DOI: 10.1002/fft2.131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Chantelle Human
- Plant Bioactives Group, Post‐Harvest and Agro‐Processing Technologies Agricultural Research Council Infruitec‐Nietvoorbij Stellenbosch South Africa
| | - Dalene De Beer
- Plant Bioactives Group, Post‐Harvest and Agro‐Processing Technologies Agricultural Research Council Infruitec‐Nietvoorbij Stellenbosch South Africa
- Department of Food Science Stellenbosch University Stellenbosch South Africa
| | - Sandra Bowles
- Biomedical Research and Innovation Platform South African Medical Research Council Bellville South Africa
- Department of Ophthalmology University of Auckland Private Bag 92019 Auckland 1142 New Zealand
| | - Elizabeth Joubert
- Plant Bioactives Group, Post‐Harvest and Agro‐Processing Technologies Agricultural Research Council Infruitec‐Nietvoorbij Stellenbosch South Africa
- Department of Food Science Stellenbosch University Stellenbosch South Africa
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Akinfenwa AO, Abdul NS, Docrat FT, Marnewick JL, Luckay RC, Hussein AA. Cytotoxic Effects of Phytomediated Silver and Gold Nanoparticles Synthesised from Rooibos (Aspalathus linearis), and Aspalathin. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112460. [PMID: 34834822 PMCID: PMC8620073 DOI: 10.3390/plants10112460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 05/05/2023]
Abstract
The green chemistry approach has continuously been applied for the synthesis of functional nanomaterials to reduce waste, environmental hazards, and the use of toxic chemicals among other reasons. Bioactive natural compounds have been found great potential in this regard and are used to improve the stability, activity, and biodistribution of metal nanoparticles (MNPs). Aspalathin (ASP) from Aspalathus linearis (rooibos) has a well-defined pharmacological profile and functional groups capable of both reducing and capping agents in the synthesis of metallic nanoparticles (NP). This study provides the first report of the phytomediated synthesis of gold and silver nanoparticles (AuNPs/AgNPs) via ASP and the green rooibos (GR) extract. The study demonstrated a green chemistry approach to the biosynthesis of nanoparticles of GR-AuNPs, ASP-AuNPs, GR-AgNPs, and ASP-AgNPs. The results showed that GR and ASP could act both as reducing and stabilising agents in the formation of crystalline, with different shapes and dispersity of NPs in the ranges of 1.6-6.7 nm for AgNPs and 7.5-12.5 nm for the AuNPs. However, the ASP NPs were less stable in selected biogenic media compared to GR NPs and were later stabilised with polyethene glycol. The cytotoxicity studies showed that GR-AgNPs were the most cytotoxic against SH-SY5Y and HepG2 with IC50 108.8 and 183.4 μg/mL, respectively. The cellular uptake analysis showed a high uptake of AuNPs and indicated that AgNPs of rooibos at a lower dose (1.3-1.5 μg/mL) is favourable for its anticancer potential. This study is a contribution to plant-mediated metallic nanoparticles using a pure single compound that can be further developed for targeted drug delivery for cancer cells treatments in the coming years.
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Affiliation(s)
- Akeem O. Akinfenwa
- Department of Chemistry, Cape Peninsula University of Technology, Bellville 7535, South Africa;
| | - Naeem S. Abdul
- Applied Microbial and Health Biotechnology Institute, Cape Peninsula University of Technology, Bellville 7535, South Africa; (N.S.A.); (F.T.D.); (J.L.M.)
| | - Fathima T. Docrat
- Applied Microbial and Health Biotechnology Institute, Cape Peninsula University of Technology, Bellville 7535, South Africa; (N.S.A.); (F.T.D.); (J.L.M.)
| | - Jeanine L. Marnewick
- Applied Microbial and Health Biotechnology Institute, Cape Peninsula University of Technology, Bellville 7535, South Africa; (N.S.A.); (F.T.D.); (J.L.M.)
| | - Robbie C. Luckay
- Chemistry & Polymer Science Department, Stellenbosch University, Matieland, Stellenbosch 7602, South Africa;
| | - Ahmed A. Hussein
- Department of Chemistry, Cape Peninsula University of Technology, Bellville 7535, South Africa;
- Correspondence: ; Tel.: +27-21-959-6193; Fax: +27-21-959-3055
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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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Mabuza N, Kinfe HH, Godeto TW, Ambushe AA. Estimated Contributions of Rooibos Tea to the Daily Manganese and Zinc Intakes Determined in Tea Leaves and Tea Infusions by Inductively Coupled Plasma-Mass Spectrometry. Biol Trace Elem Res 2021; 199:1145-1152. [PMID: 32557112 DOI: 10.1007/s12011-020-02211-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 05/19/2020] [Indexed: 01/13/2023]
Abstract
Rooibos tea, scientific name Aspalathus linearis, is a popular tea grown in South Africa and consumed worldwide for its unique taste and presumed health benefits. There is a growing interest in using rooibos tea as a supplement for the deficiency of metallic nutrients in South Africa. In this study, the total concentrations of manganese (Mn) and zinc (Zn) in acid-digested tea leaves and the corresponding tea infusions were determined by inductively coupled plasma-mass spectrometry (ICP-MS) to estimate the contribution of rooibos tea consumption to the recommended daily allowance (RDA) of Mn and Zn in consumers. The accuracy of microwave-assisted acid digestion and tea infusion methods were checked by analyzing INCT-TL-1 tea leaves certified reference material (CRM) and samples spiked with standards, respectively. Both methods yielded quantitative percentage recoveries for Mn and Zn. Rooibos tea leaves and the corresponding infusions are composed of higher levels of Mn than Zn where 40.9 to 85.7 μg Mn/g and 4.15 to 12.2 μg Zn/g were found in digested tea leaves and 11.8 to 30.2 μg Mn/g and 1.51 to 4.59 μg Zn/g in tea infusions. These results indicate the contribution of about 1.0 to 3.2% Mn and 0.03 to 0.08% Zn in males approximately ≥ 9 years of age and 1.3 to 3.8% Mn and 0.04 to 0.11% Zn in females of the same age group as males of the RDA from drinking a cup of tea obtained by infusing a 2-g bag of rooibos tea.
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Affiliation(s)
- Nombuzo Mabuza
- Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa
| | - Henok H Kinfe
- Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa
| | - Taddese W Godeto
- Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa
- Laboratory Services Branch, Ministry of the Environment, Conservation and Parks, M9P3V6, Toronto, ON, Canada
| | - Abayneh A Ambushe
- Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, 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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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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