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Prof. Elizabeth Joubert
Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council, Stellenbosch, South Africa Department of Food Science, Stellenbosch University, Stellenbosch, South Africa

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0 Nutraceuticals
0 Processing
0 Stability
0 composition
0 Herbal Tea

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Journal article
Published: 30 August 2021 in Molecules
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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.

ACS Style

Chantelle Human; Dalene de Beer; Magdalena Muller; Marieta van der Rijst; Marique Aucamp; Andreas Tredoux; André de Villiers; Elizabeth Joubert. Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder—Assessment of Physical, Chemical, and Sensory Properties. Molecules 2021, 26, 5260 .

AMA Style

Chantelle Human, Dalene de Beer, Magdalena Muller, Marieta van der Rijst, Marique Aucamp, Andreas Tredoux, André de Villiers, Elizabeth Joubert. Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder—Assessment of Physical, Chemical, and Sensory Properties. Molecules. 2021; 26 (17):5260.

Chicago/Turabian Style

Chantelle Human; Dalene de Beer; Magdalena Muller; Marieta van der Rijst; Marique Aucamp; Andreas Tredoux; André de Villiers; Elizabeth Joubert. 2021. "Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder—Assessment of Physical, Chemical, and Sensory Properties." Molecules 26, no. 17: 5260.

Research article
Published: 27 July 2021 in Journal of the Science of Food and Agriculture
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BACKGROUND Ultrafiltration of green honeybush (Cyclopia genistoides) extract results in a by-product (retentate). Application of further separation processes for recovery of polyphenols would entail creation of additional waste. Repurposing the retentate as a food flavour ingredient provides an alternative valorisation approach. RESULTS The retentate, suspended in water (270 g L−1), was heat-treated at 80 °C for 2, 4, 8 and 16 h, and at 90 °C for 2, 4, 6 and 8 h to change its sensory profile. The heat-treated retentate, diluted to beverage strength (2.15 g L−1), had prominent ‘grape/Muscat-like’ and ‘marmalade/citrus’ aroma and flavour notes. Overall, heating for ≤4 h increased the intensities of positive flavour and aroma notes, while reducing that of ‘green/grass’, ‘hay’ and bitterness, whereafter further heating only had a slight effect on the aroma profile at 80 °C (P < 0.05), but not at 90 °C (P ≥ 0.05). The heat treatments, 80 °C/4 h and 90 °C/4 h, were subsequently applied to different batches of retentate (n = 10) to accommodate the effect of natural product variation. Heating at 90 °C produced higher intensities of positive aroma attributes (P < 0.05), but was more detrimental to the phenolic stability, compared to 80 °C. CONCLUSION After heat treatment, the phenolic content of C. genistoides retentate, reconstituted to beverage strength, still fell within the range of a typical fermented honeybush leaf tea infusion. The change in phenolic composition will not diminish the benefit of an improved sensory profile for the retentate by-product through heating.

ACS Style

Neil Miller; Alicia Petrus; Erika Ilette Moelich; Magdalena Muller; Dalene de Beer; Marieta van der Rijst; Elizabeth Joubert. Heat treatment improves the sensory properties of the ultrafiltration by‐product of honeybush ( Cyclopia genistoides ) extract. Journal of the Science of Food and Agriculture 2021, 1 .

AMA Style

Neil Miller, Alicia Petrus, Erika Ilette Moelich, Magdalena Muller, Dalene de Beer, Marieta van der Rijst, Elizabeth Joubert. Heat treatment improves the sensory properties of the ultrafiltration by‐product of honeybush ( Cyclopia genistoides ) extract. Journal of the Science of Food and Agriculture. 2021; ():1.

Chicago/Turabian Style

Neil Miller; Alicia Petrus; Erika Ilette Moelich; Magdalena Muller; Dalene de Beer; Marieta van der Rijst; Elizabeth Joubert. 2021. "Heat treatment improves the sensory properties of the ultrafiltration by‐product of honeybush ( Cyclopia genistoides ) extract." Journal of the Science of Food and Agriculture , no. : 1.

Journal article
Published: 24 July 2021 in Journal of Food Composition and Analysis
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Low-chill requiring (LCR) apple cultivars provide the South African apple juice industry the opportunity to mitigate the effects of climate change on production. The juicing potential (yield and physicochemical properties) of six LCR and two pink-fleshed (PF) apple cultivars, harvested in 2018, were compared to that of commercial cultivars. In 2019, the phenolic and sensory profiles of the juice of the three most promising LCR cultivars were also compared to that of the two PF and commercial cultivars. LCR and PF cultivars had similar or lower juice yields and juice with lower sugar content than the commercial cultivars. LCR cultivars produced juice containing less polyphenols than PF cultivars (p < 0.05), but similar or higher amounts than commercial cultivars. Of the PF cultivars, KAZ 95−91 juice was higher in p-coumaroylquinic acid, flavan-3-ols and procyanidins, and TC3 juice had the higher chlorogenic acid concentration (p < 0.05), but similar flavonol and anthocyanin concentrations. The ‘litchi/pear’ and ‘strawberry’ aroma notes of Afri Glo (LCR) and TC3, respectively, could offer the consumer apple juice with new aroma profiles. The less sweet juice of LCR and PF cultivars could furthermore cater for health-conscious consumers.

ACS Style

J. Hermine Stander; Magdalena Muller; Elizabeth Joubert; Iwan F. Labuschagné; Dalene De Beer. Potential of low-chill requiring and pink-fleshed apple cultivars for cloudy juice production. Journal of Food Composition and Analysis 2021, 103, 104089 .

AMA Style

J. Hermine Stander, Magdalena Muller, Elizabeth Joubert, Iwan F. Labuschagné, Dalene De Beer. Potential of low-chill requiring and pink-fleshed apple cultivars for cloudy juice production. Journal of Food Composition and Analysis. 2021; 103 ():104089.

Chicago/Turabian Style

J. Hermine Stander; Magdalena Muller; Elizabeth Joubert; Iwan F. Labuschagné; Dalene De Beer. 2021. "Potential of low-chill requiring and pink-fleshed apple cultivars for cloudy juice production." Journal of Food Composition and Analysis 103, no. : 104089.

Journal article
Published: 21 July 2021 in Appetite
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Globally, the role of food labels in reducing non-communicable disease remains a point of debate. A particular area of contention is the use of health claims, an approach currently under consideration in South Africa - a developing country with vast socio-economic disparity. In the present study, in-depth interviews were conducted with 49 diverse stakeholders, including consumers and professionals from the food industry and other occupations, who shared their views about the use of health claims in a developing country context. The qualitative approach and inclusion of multiple perspectives that had not been motivated by a single stakeholder group added a novel view. Themes identified based on inductive analysis included: (i) practical barriers to label use; (ii) contextual and personal variables influencing engagement with label information; (iii) messaging preferences (for positively worded claims, compared to more cautionary statements); (iv) stakeholder complexities – mainly related to responsibility and trust; and (v) ambassadors to change. Findings indicate that there are persistent barriers to label use, such as challenges related to literacy and legibility. Furthermore, the socio-economic circumstances prevalent in South Africa drive large volumes of food sales in informal markets where labels are often not present. Unresolved questions about the substantiation and enforcement of health claims, combined with no solution being apparent for reaching consumers in the informal market, would limit the benefits that could be associated with the implementation of health claims at this point in time.

ACS Style

Melvi Todd; Timothy Guetterman; Gunnar Sigge; Elizabeth Joubert. Multi-stakeholder perspectives on food labeling and health claims: Qualitative insights from South Africa. Appetite 2021, 167, 105606 .

AMA Style

Melvi Todd, Timothy Guetterman, Gunnar Sigge, Elizabeth Joubert. Multi-stakeholder perspectives on food labeling and health claims: Qualitative insights from South Africa. Appetite. 2021; 167 ():105606.

Chicago/Turabian Style

Melvi Todd; Timothy Guetterman; Gunnar Sigge; Elizabeth Joubert. 2021. "Multi-stakeholder perspectives on food labeling and health claims: Qualitative insights from South Africa." Appetite 167, no. : 105606.

Journal article
Published: 20 July 2021 in Innovative Food Science & Emerging Technologies
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This study evaluated the bubble structure of freeze-dried dough and foam properties of bread produced from the roasted wheat flour by means of X-ray micro-computed tomography (μCT). Wheat was roasted at 90 °C and 86 Hz, of which the conditions was determined by means of a central composite design, and the flour used to produce dough proofed for 20- and 40 min as well as bread. The use of 10 g dough and bread samples enabled scanning at a much higher resolution. Roasting resulted in a decreased strut thickness of the bread, suggesting a finer crumb structure and softer texture, compared to the control. Porosity increases were observed for the roasted wheat samples. This suggested a slightly weaker gluten strength as was observed with the lower mixograph peak height. Roasting wheat, at the conditions determined by the central composite design, did not negatively affect the foam properties of the breads produced from the roasted wheat flour.

ACS Style

Zandré Germishuys; Marena Manley. X-ray micro-computed tomography evaluation of bubble structure of freeze-dried dough and foam properties of bread produced from roasted wheat flour. Innovative Food Science & Emerging Technologies 2021, 73, 102766 .

AMA Style

Zandré Germishuys, Marena Manley. X-ray micro-computed tomography evaluation of bubble structure of freeze-dried dough and foam properties of bread produced from roasted wheat flour. Innovative Food Science & Emerging Technologies. 2021; 73 ():102766.

Chicago/Turabian Style

Zandré Germishuys; Marena Manley. 2021. "X-ray micro-computed tomography evaluation of bubble structure of freeze-dried dough and foam properties of bread produced from roasted wheat flour." Innovative Food Science & Emerging Technologies 73, no. : 102766.

Journal article
Published: 16 June 2021 in Journal of Food Composition and Analysis
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The elemental analysis of tea is essential since it is a commonly consumed beverage around the world. In this paper, non-destructive energy dispersive X-ray fluorescence spectrometry (EDXRF) using a standardless method based on fundamental parameters was applied in honeybush and rooibos analysis. Tea samples were measured directly in the form of loose powders. The observed element concentrations (mg kg−1) were as follows: Ca (1260–3990), Cl (914–7710), K (2270–7190), Mg (374–2510), S (474–1320), P (183−1210), Si (303−1580), Al (92–765), Fe (67–514), Mn (26–163), Cr (1.8–20), Cu (2.2–11.5), Ni (1.1–5), Rb (0.8–8), Sr (5.4–24.5), Ti (4.1–39), and Zn (4.2–18.6). What is more, the determined concentrations (mg kg−1) of selected elements in rooibos and honeybush, are statistically different: Cl (2200–7710 rooibos and 913.7–2160 honeybush); Mg (1232–3465 rooibos and 535.9–1030 honeybush); P (388.0–1566 rooibos and 244.0–403.6 honeybush); Br (12.1–52.8 rooibos and 1.6–5.3 honeybush). Multivariate analysis of variance (ANOVA) was successfully applied to the data, showing statistical significance of the concentration differences for all the elements in both types of tea. The developed method provided good precision (RSD < 6%) with an accuracy of more than 90 %, and LOD ∼ 0.5 mg kg-1- for trace elements. The method was validated using suitable certified reference materials of tea (CRM).

ACS Style

Beata Zawisza; Marcin Musielak; Dalene de Beer; Elizabeth Joubert; Beata Walczak. Non-destructive elemental analysis of herbal teas from South Africa. Journal of Food Composition and Analysis 2021, 102, 104041 .

AMA Style

Beata Zawisza, Marcin Musielak, Dalene de Beer, Elizabeth Joubert, Beata Walczak. Non-destructive elemental analysis of herbal teas from South Africa. Journal of Food Composition and Analysis. 2021; 102 ():104041.

Chicago/Turabian Style

Beata Zawisza; Marcin Musielak; Dalene de Beer; Elizabeth Joubert; Beata Walczak. 2021. "Non-destructive elemental analysis of herbal teas from South Africa." Journal of Food Composition and Analysis 102, no. : 104041.

Research article
Published: 13 May 2021 in PLoS ONE
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Oral therapeutics used to treat type 2 diabetes and cardiovascular disease often fail to prevent the progression of disease and their comorbidities. Rooibos (Aspalathus linearis), an endemic South African plant used as an herbal tea, has demonstrated positive effects on glycemia and hypercholesterolemia. However, the treatment efficacy of rooibos extract in combination with conventional hypoglycemic and hypolipidemic medications on blood glucose and lipid profiles has not been established. This study aimed to investigate the effects of combining an aspalathin-rich green rooibos extract (Afriplex GRT™) with pioglitazone and atorvastatin, on blood glucose and lipid levels in obese diabetic (db/db) mice. Six-week-old male db/db mice and their nondiabetic lean littermate controls (db+) were divided into 8 experimental groups (n = 6/group). Db/db mice were treated daily either with pioglitazone (25 mg/kg), atorvastatin (80 mg/kg) and GRT (100 mg/kg), a combination of either drug with GRT or a combination of GRT-pioglitazone and atorvastatin for 5 weeks. Untreated vehicle controls were given dimethyl sulfoxide (0.1%) and phosphate buffered saline solution. At termination, serum and liver tissue were collected for lipid and gene expression analysis. Treatment with GRT, pioglitazone and atorvastatin combination effectively lowered fasting plasma glucose (FPG) levels in db/db mice (p = 0.02), whilst increasing body weight, liver weight, and reducing retroperitoneal fat weight. Atorvastatin monotherapy was effective at reducing cholesterol (from 4.00 ± 0.12 to 2.93 ± 0.13, p = 0.0003), LDL-C (from 0.58 ± 0.04 to 0.50 ± 0.00, p = 0.04), HDL-C (from 2.86 ± 0.05 to 2.50 ± 0.04, p = 0.0003) and TG (from 2.77 ± 0.50 to 1.48 ± 0.23, p = 0.04), compared to the untreated diabetic control. The hypotriglyceridemic effect of atorvastatin was enhanced when used in combination with both GRT and pioglitazone. The addition of pioglitazone to GRT significantly lowered FPG and TG. In db/db mice, Apoa1 was significantly downregulated in the liver, whilst Pparγ was significantly upregulated compared to their db+ counterparts. GRT monotherapy downregulated Apoa1 expression (p = 0.02). Atorvastatin combined with GRT significantly downregulated mRNA expression of Apoa1 (p = 0.03), whilst upregulating the expression of Pparγ (p = 0.03), Pparα (p = 0.002), Srebp1 (p = 0.002), and Fasn (p = 0.04). The GRT-pioglitazone-atorvastatin combination therapy downregulated Apoa1 (p = 0.006), whilst upregulating Fasn (p = 0.005), Pparα (p = 0.041), and Srebp1 (p = 0.03). Natural products can improve the efficacy of current drugs to prevent diabetes-associated complications. GRT in combination with pioglitazone enhanced the reduction of FPG, whilst the addition of atorvastatin to the combination, significantly lowered triglyceride levels. However, when GRT was used in combination with atorvastatin only cholesterol levels were affected. Although these results confirm both glucose- and lipoprotein-lowering biological effects of GRT in combination with pioglitazone and atorvastatin, increased expression of genes involved in lipogenesis, cholesterol, and fatty acid transport, β-oxidation, and synthesis and storage of fatty acids, may exacerbate the hepatotoxic effects of atorvastatin.

ACS Style

Oelfah Patel; Christo J. F. Muller; Elizabeth Joubert; Bernd Rosenkranz; Johan Louw; Charles Awortwe. Therapeutic effects of an aspalathin-rich green rooibos extract, pioglitazone and atorvastatin combination therapy in diabetic db/db mice. PLoS ONE 2021, 16, e0251069 .

AMA Style

Oelfah Patel, Christo J. F. Muller, Elizabeth Joubert, Bernd Rosenkranz, Johan Louw, Charles Awortwe. Therapeutic effects of an aspalathin-rich green rooibos extract, pioglitazone and atorvastatin combination therapy in diabetic db/db mice. PLoS ONE. 2021; 16 (5):e0251069.

Chicago/Turabian Style

Oelfah Patel; Christo J. F. Muller; Elizabeth Joubert; Bernd Rosenkranz; Johan Louw; Charles Awortwe. 2021. "Therapeutic effects of an aspalathin-rich green rooibos extract, pioglitazone and atorvastatin combination therapy in diabetic db/db mice." PLoS ONE 16, no. 5: e0251069.

Primer
Published: 25 February 2021 in Nature Reviews Methods Primers
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X-ray computed tomography (CT) can reveal the internal details of objects in three dimensions non-destructively. In this Primer, we outline the basic principles of CT and describe the ways in which a CT scan can be acquired using X-ray tubes and synchrotron sources, including the different possible contrast modes that can be exploited. We explain the process of computationally reconstructing three-dimensional (3D) images from 2D radiographs and how to segment the 3D images for subsequent visualization and quantification. Whereas CT is widely used in medical and heavy industrial contexts at relatively low resolutions, here we focus on the application of higher resolution X-ray CT across science and engineering. We consider the application of X-ray CT to study subjects across the materials, metrology and manufacturing, engineering, food, biological, geological and palaeontological sciences. We examine how CT can be used to follow the structural evolution of materials in three dimensions in real time or in a time-lapse manner, for example to follow materials manufacturing or the in-service behaviour and degradation of manufactured components. Finally, we consider the potential for radiation damage and common sources of imaging artefacts, discuss reproducibility issues and consider future advances and opportunities. This Primer on X-ray computed tomography explores the different experimental configurations for three-dimensional data acquisition as well as the fundamentals of three-dimensional data reconstruction, segmentation and analysis with examples across the physical and life sciences.

ACS Style

Philip J. Withers; Charles Bouman; Simone Carmignato; Veerle Cnudde; David Grimaldi; Charlotte K. Hagen; Eric Maire; Marena Manley; Anton Du Plessis; Stuart R. Stock. X-ray computed tomography. Nature Reviews Methods Primers 2021, 1, 1 -21.

AMA Style

Philip J. Withers, Charles Bouman, Simone Carmignato, Veerle Cnudde, David Grimaldi, Charlotte K. Hagen, Eric Maire, Marena Manley, Anton Du Plessis, Stuart R. Stock. X-ray computed tomography. Nature Reviews Methods Primers. 2021; 1 (1):1-21.

Chicago/Turabian Style

Philip J. Withers; Charles Bouman; Simone Carmignato; Veerle Cnudde; David Grimaldi; Charlotte K. Hagen; Eric Maire; Marena Manley; Anton Du Plessis; Stuart R. Stock. 2021. "X-ray computed tomography." Nature Reviews Methods Primers 1, no. 1: 1-21.

Review
Published: 18 February 2021 in Foods
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In recent years, meat authenticity awareness has increased and, in the fight to combat meat fraud, various analytical methods have been proposed and subsequently evaluated. Although these methods have shown the potential to detect low levels of adulteration with high reliability, they are destructive, time-consuming, labour-intensive, and expensive. Therefore, rendering them inappropriate for rapid analysis and early detection, particularly under the fast-paced production and processing environment of the meat industry. However, modern analytical methods could improve this process as the food industry moves towards methods that are non-destructive, non-invasive, simple, and on-line. This review investigates the feasibility of different non-destructive techniques used for processed meat authentication which could provide the meat industry with reliable and accurate real-time monitoring, in the near future.

ACS Style

Kiah Edwards; Marena Manley; Louwrens C. Hoffman; Paul J. Williams. Non-Destructive Spectroscopic and Imaging Techniques for the Detection of Processed Meat Fraud. Foods 2021, 10, 448 .

AMA Style

Kiah Edwards, Marena Manley, Louwrens C. Hoffman, Paul J. Williams. Non-Destructive Spectroscopic and Imaging Techniques for the Detection of Processed Meat Fraud. Foods. 2021; 10 (2):448.

Chicago/Turabian Style

Kiah Edwards; Marena Manley; Louwrens C. Hoffman; Paul J. Williams. 2021. "Non-Destructive Spectroscopic and Imaging Techniques for the Detection of Processed Meat Fraud." Foods 10, no. 2: 448.

Journal article
Published: 09 February 2021 in Food Chemistry
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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.

ACS Style

Chantelle Human; Ombeline Danton; Dalene De Beer; Takuma Maruyama; Lara Alexander; Christiaan Malherbe; Matthias Hamburger; Elizabeth Joubert. 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 Chemistry 2021, 351, 129273 .

AMA Style

Chantelle Human, Ombeline Danton, Dalene De Beer, Takuma Maruyama, Lara Alexander, Christiaan Malherbe, Matthias Hamburger, Elizabeth Joubert. 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 Chemistry. 2021; 351 ():129273.

Chicago/Turabian Style

Chantelle Human; Ombeline Danton; Dalene De Beer; Takuma Maruyama; Lara Alexander; Christiaan Malherbe; Matthias Hamburger; Elizabeth Joubert. 2021. "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 Chemistry 351, no. : 129273.

Journal article
Published: 04 February 2021 in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
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NIR spectroscopy combined with chemometric analysis has proven to be a rapid and cost-effective screening tool for the detection of syrup-adulterated honey. Processing and storage conditions which alter the chemical and physical state of honey may affect the spectra. The effects of age, storage temperature, syrup adulteration (10 and 20% w/w) and irradiation treatment on the NIR spectra of honey were investigated as a function of time with ANOVA-simultaneous component analysis (ASCA), an experimental design-focused exploratory data analysis method. The factors ‘time’, ‘temperature’ and ‘adulteration’ were found to have significant effects (p < 0.05), but no significant effect was observed for irradiation treatment. A significant interaction effect was found between factors ‘time’ and ‘adulteration’, with the greatest disparity between authentic and adulterated class signals found immediately after adulteration and decreasing within three months thereafter.

ACS Style

Alexandra Rust; Federico Marini; Mike Allsopp; Paul J. Williams; Marena Manley. Application of ANOVA-simultaneous component analysis to quantify and characterise effects of age, temperature, syrup adulteration and irradiation on near-infrared (NIR) spectral data of honey. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2021, 253, 119546 .

AMA Style

Alexandra Rust, Federico Marini, Mike Allsopp, Paul J. Williams, Marena Manley. Application of ANOVA-simultaneous component analysis to quantify and characterise effects of age, temperature, syrup adulteration and irradiation on near-infrared (NIR) spectral data of honey. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 2021; 253 ():119546.

Chicago/Turabian Style

Alexandra Rust; Federico Marini; Mike Allsopp; Paul J. Williams; Marena Manley. 2021. "Application of ANOVA-simultaneous component analysis to quantify and characterise effects of age, temperature, syrup adulteration and irradiation on near-infrared (NIR) spectral data of honey." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 253, no. : 119546.

Journal article
Published: 21 November 2020 in LWT
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Honeybush tea infusions, especially those prepared from Cyclopia genistoides, can be unacceptably bitter, given the association of this herbal tea with sweet taste. Infusions prepared from both ‘fermented’ (high-temperature oxidised) Cyclopia longifolia and C. genistoides contain high levels of the bitter xanthone, mangiferin, however, C. longifolia is generally less bitter than C. genistoides. The effect of phenolic changes during fermentation on the bitterness of infusions was determined for both species. The bitter intensity of the infusions was reduced by 34-68% for C. genistoides and 55-86% for C. longifolia. Fermentation affected the phenolic composition of the two species differently, notably the ratio of mangiferin to isomangiferin remained higher for C. genistoides. Bitterness prediction models for two data sets (126 fermented and green infusions; 122 fermented infusions) including variable selection based on phenolic content gave good performance (RMSECV < 5). Nine compounds, depending on the data set, were determined to be important for the models, including xanthones, benzophenones, flavones and flavanones. Mangiferin, two tetrahydroxyxanthone-di-O,C-hexose isomers, 3-β-D-glucopyranosyliriflophenone, vicenin-2 and scolymoside were common to both models. Future application of the model would be to screen large numbers of genotypes for the breeding of selections with low bitterness potential based on phenolic composition.

ACS Style

Lara Alexander; Erika Ilette Moelich; Dalene de Beer; Magdalena Muller; Beata Walczak; Elizabeth Joubert. High-temperature oxidation reduces the bitterness of honeybush infusions depending on changes in phenolic composition. LWT 2020, 139, 110608 .

AMA Style

Lara Alexander, Erika Ilette Moelich, Dalene de Beer, Magdalena Muller, Beata Walczak, Elizabeth Joubert. High-temperature oxidation reduces the bitterness of honeybush infusions depending on changes in phenolic composition. LWT. 2020; 139 ():110608.

Chicago/Turabian Style

Lara Alexander; Erika Ilette Moelich; Dalene de Beer; Magdalena Muller; Beata Walczak; Elizabeth Joubert. 2020. "High-temperature oxidation reduces the bitterness of honeybush infusions depending on changes in phenolic composition." LWT 139, no. : 110608.

Journal article
Published: 19 November 2020 in Food Control
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Rooibos (Aspalathus linearis) and honeybush (Cyclopia species) are popular indigenous herbal teas originating from South Africa. Both are enjoyed for their taste and aroma and more importantly, valued for their medicinal properties such as antioxidant, anti-diabetic, anti-inflammatory or immunomodulatory activity. In the European Union, rooibos and honeybush are protected as Geographical Indications. The Geographical Indication refers to products with unique characteristics that are related to their geographical origin. The authentication of products labelled as GIs is regarded as an issue of food quality and safety. Routine quality control procedures of GIs products prevent their fraud and counterfeiting on the market. However, techniques to determine adulteration or mislabelling of rooibos and honeybush do not exist yet. Therefore, in this study, the authentication of rooibos and honeybush based on their elemental composition was investigated. The methodology presented in this study combines energy-dispersive X-ray fluorescence spectrometry (EDXRF) for elemental analysis and a one-class classification approach. Elemental composition of plant material highly depends on soil on which the plant has been grown, but also on some other factors such as, e.g., atmospheric pollution, or plant metabolism. Determination of the elemental composition of the samples by EDXRF is non-destructive and does not require any complex sample preparation. One-class classification methods are well suited for authentication and origin verification problems. Based on the EDXRF data of samples from studied teas, individual class models were constructed for rooibos and honeybush. Several linear and nonlinear classification techniques were tested in order to find the model that handles the authentication task the best. For honeybush tea, the best classification results were obtained with the use of a nonlinear method based on Potential Functions. For rooibos tea, the highest classification outcomes were obtained by nonlinear One Class Partial Least Squares (OC-PLS) and the machine learning technique, Support Vector Domain Description (SVDD). The methodology implemented in the present study has the potential to be successfully applied for routine authentication of honeybush and rooibos teas.

ACS Style

Zuzanna Małyjurek; Beata Zawisza; Dalene de Beer; Elizabeth Joubert; Beata Walczak. Authentication of honeybush and rooibos herbal teas based on their elemental composition. Food Control 2020, 123, 107757 .

AMA Style

Zuzanna Małyjurek, Beata Zawisza, Dalene de Beer, Elizabeth Joubert, Beata Walczak. Authentication of honeybush and rooibos herbal teas based on their elemental composition. Food Control. 2020; 123 ():107757.

Chicago/Turabian Style

Zuzanna Małyjurek; Beata Zawisza; Dalene de Beer; Elizabeth Joubert; Beata Walczak. 2020. "Authentication of honeybush and rooibos herbal teas based on their elemental composition." Food Control 123, no. : 107757.

Chapter
Published: 14 November 2020 in Near-Infrared Spectroscopy
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The combination of speed, accuracy and simplicity provided by NIR spectroscopy ensured its use as a preferred quality control tool in the food and beverage industries. These applications are increasingly simplified by the availability of readily available factory calibrations. A challenge receiving increasing attention is that of the detection of food adulteration, and a large effort is being made to evaluate NIR spectroscopy as a suitable method. The recent trend towards miniaturisation of NIR instruments contributes to the technology becoming portable and more affordable. The trust put into NIR spectroscopy as an effective analytical tool in the food industry will remain. In addition, investigations into new and innovative applications to the benefit of the food industry are seen on a daily basis.

ACS Style

Marena Manley; Paul James Williams. Applications: Food Science. Near-Infrared Spectroscopy 2020, 347 -359.

AMA Style

Marena Manley, Paul James Williams. Applications: Food Science. Near-Infrared Spectroscopy. 2020; ():347-359.

Chicago/Turabian Style

Marena Manley; Paul James Williams. 2020. "Applications: Food Science." Near-Infrared Spectroscopy , no. : 347-359.

Original papers
Published: 03 November 2020 in Planta Medica
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Fractions of an ultrafiltered Cyclopia genistoides extract, respectively enriched in xanthones and benzophenones, were previously shown to inhibit mammalian α-glucosidase in vitro. The present study investigated ex vivo intestinal transport of these fractions, using excised porcine jejunal tissue, to determine whether the gut could be a predominant in vivo site of action. The major bioactive compounds, the xanthones (mangiferin, isomangiferin) and benzophenones (3-β-D-glucopyranosyliriflophenone, 3-β-D-glucopyranosyl-4-O-β-D-glucopyranosyliriflophenone) exhibited poor permeation in the absorptive direction with a relatively high efflux ratio (efflux ratio > 1). The efflux ratio of 3-β-D-glucopyranosyl-4-O-β-D-glucopyranosyliriflophenone (3.05) was similar to rhodamine 123 (2.99), a known substrate of intestinal P-glycoprotein 1 efflux transporters. Low epithelial membrane transport rates, coupled with efflux mechanisms, would effectively concentrate these bioactive compounds at the target site (gut lumen). Storage stability testing and moisture sorption assays of the xanthone-enriched fraction, benzophenone-enriched fraction, and ultrafiltered Cyclopia genistoides extract were performed to determine their susceptibility to physical and chemical degradation during storage. Hygroscopicity of the powders, indicated by moisture uptake, decreased in the order: benzophenone-enriched fraction (22.7%) > ultrafiltered Cyclopia genistoides extract (14.0%) > xanthone-enriched fraction (10.7%). 3-β-D-Glucopyranosylmaclurin, a minor benzophenone, was the least stable of the compounds, degrading faster in the benzophenone-enriched fraction than in ultrafiltered Cyclopia genistoides extract, suggesting that the ultrafiltered extract matrix may provide a degree of protection against chemical degradation. Compound degradation during 12 wk of storage at 40 °C in moisture-impermeable containers was best explained by first order reaction kinetics.

ACS Style

Neil Miller; Christiaan Johannes Malherbe; Werner Gerber; Josias H. Hamman; Marieta van der Rijst; Marique Aucamp; Elizabeth Joubert. Physicochemical Stability of Enriched Phenolic Fractions of Cyclopia genistoides and ex vivo Bi-directional Permeability of Major Xanthones and Benzophenones. Planta Medica 2020, 87, 325 -335.

AMA Style

Neil Miller, Christiaan Johannes Malherbe, Werner Gerber, Josias H. Hamman, Marieta van der Rijst, Marique Aucamp, Elizabeth Joubert. Physicochemical Stability of Enriched Phenolic Fractions of Cyclopia genistoides and ex vivo Bi-directional Permeability of Major Xanthones and Benzophenones. Planta Medica. 2020; 87 (04):325-335.

Chicago/Turabian Style

Neil Miller; Christiaan Johannes Malherbe; Werner Gerber; Josias H. Hamman; Marieta van der Rijst; Marique Aucamp; Elizabeth Joubert. 2020. "Physicochemical Stability of Enriched Phenolic Fractions of Cyclopia genistoides and ex vivo Bi-directional Permeability of Major Xanthones and Benzophenones." Planta Medica 87, no. 04: 325-335.

Journal article
Published: 23 October 2020 in Biology
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The traditional use of Aloe spp. for the purpose of wound healing has a long history and is widespread internationally. Recently, a hybrid aloe plant (Aloe muth-muth) has been cultivated by cross pollination between Aloe vera and Aloe ferox. The Aloe muth-muth plant has not yet been investigated for medicinal properties and provides an opportunity for potential biological activity, including wound healing. The aim of this study was to investigate the in vitro wound healing effects of both Aloe muth-muth gel and whole leaf material with the use of the immortalized human keratinocyte (HaCaT) cell line. Cell viability was conducted using methyl thiazolyl tetrazolium (MTT) assays. In vitro wound healing was tested on HaCaT cells using an established scratch assay method. The effect of Aloe muth-muth gel material on HaCaT cell migration was also investigated. Aloe muth-muth gel material exhibited statistically significantly (p < 0.05) higher percentage wound closure compared to the control at all three concentrations investigated. These findings confirm that this newly cultivated species, Aloe muth-muth, also possesses wound healing activity corresponding to that reported for the two species it is derived from, namely, Aloe vera and Aloe ferox. Therefore, Aloe muth-muth has the potential to be used in future wound therapeutics.

ACS Style

Morné Fouché; Clarissa Willers; Sias Hamman; Christiaan Malherbe; Jan Steenekamp. Wound Healing Effects of Aloe muth-muth: In Vitro Investigations Using Immortalized Human Keratinocytes (HaCaT). Biology 2020, 9, 350 .

AMA Style

Morné Fouché, Clarissa Willers, Sias Hamman, Christiaan Malherbe, Jan Steenekamp. Wound Healing Effects of Aloe muth-muth: In Vitro Investigations Using Immortalized Human Keratinocytes (HaCaT). Biology. 2020; 9 (11):350.

Chicago/Turabian Style

Morné Fouché; Clarissa Willers; Sias Hamman; Christiaan Malherbe; Jan Steenekamp. 2020. "Wound Healing Effects of Aloe muth-muth: In Vitro Investigations Using Immortalized Human Keratinocytes (HaCaT)." Biology 9, no. 11: 350.

Review article
Published: 13 October 2020 in Journal of Functional Foods
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The discourse regarding plant-based preservatives for food application has generally revolved around extracts from commercial fruits, vegetables, herbs and spices with indigenous fruits (IFs) on the periphery, with little investment into their valorisation. While being important food sources at community level, IFs and their byproducts are also incorporated into medicinal remedies, combating various diseases. Their ethnomedicinal usage indicates potent bioactive profile that alleviate effects of oxidative stress, which accompany disease in vivo. This is supported by in vitro antioxidant activity of the IFs and their byproducts. As such, the current review explores the potential of bioprospecting extracts from nine IFs and their byproducts as food antioxidants. Evidence presented shows that IFs have high content of bioactive compounds further translating to high antioxidant activity. Research gaps in information concerning in vitro bioactivity warrant further research to provide impetus for valorisation and food application of IFs.

ACS Style

Trust M. Pfukwa; Obert C. Chikwanha; Chenaimoyo L.F. Katiyatiya; Olaniyi A. Fawole; Marena Manley; Cletos Mapiye. Southern African indigenous fruits and their byproducts: Prospects as food antioxidants. Journal of Functional Foods 2020, 75, 104220 .

AMA Style

Trust M. Pfukwa, Obert C. Chikwanha, Chenaimoyo L.F. Katiyatiya, Olaniyi A. Fawole, Marena Manley, Cletos Mapiye. Southern African indigenous fruits and their byproducts: Prospects as food antioxidants. Journal of Functional Foods. 2020; 75 ():104220.

Chicago/Turabian Style

Trust M. Pfukwa; Obert C. Chikwanha; Chenaimoyo L.F. Katiyatiya; Olaniyi A. Fawole; Marena Manley; Cletos Mapiye. 2020. "Southern African indigenous fruits and their byproducts: Prospects as food antioxidants." Journal of Functional Foods 75, no. : 104220.

Research article
Published: 15 September 2020 in Nutrition and Cancer
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Differential anti-proliferative and pro-apoptotic effects of aqueous extracts of green rooibos (Rg; Aspalathus linearis) and green tea (GT; Camellia sinensis) and an aspalathin-enriched extract of green rooibos (GRE), were investigated in primary rat hepatocytes (PH) and human liver (HepG2) and colon (HT-29) cancer cells. Rooibos flavonoids, aspalathin and luteolin, and the green tea flavanol, epigallocatechin gallate (EGCG), were included to assess their contribution relative to their extract concentrations. GRE was the most effective in reducing cell growth parameters which was associated with a high total polyphenol content and high ferric reducing potential. Differential cell responses were noticed with HepG2 cells more sensitive than PH toward the induction of apoptosis by GRE. Luteolin induced apoptosis in PH and HepG2 cells while aspalathin lacked any effect. EGCG induced apoptosis in HepG2 cells while PH were resistant. HT-29 cells were resistant to apoptosis induction by the tea and pure flavonoids. Differences existed in the individual effects of the major rooibos and GT flavonoids against cell growth parameters compared to their equivalent concentrations in the extract mixtures. Diversity of the flavonoid constituents, physicochemical properties and cellular redox status governing cell survival are likely to explain the differential cell responses.

ACS Style

Sedicka Samodien; Maryna de Kock; Elizabeth Joubert; Sonja Swanevelder; Wentzel C. A. Gelderblom. Differential Cytotoxicity of Rooibos and Green Tea Extracts against Primary Rat Hepatocytes and Human Liver and Colon Cancer Cells – Causal Role of Major Flavonoids. Nutrition and Cancer 2020, 1 -15.

AMA Style

Sedicka Samodien, Maryna de Kock, Elizabeth Joubert, Sonja Swanevelder, Wentzel C. A. Gelderblom. Differential Cytotoxicity of Rooibos and Green Tea Extracts against Primary Rat Hepatocytes and Human Liver and Colon Cancer Cells – Causal Role of Major Flavonoids. Nutrition and Cancer. 2020; ():1-15.

Chicago/Turabian Style

Sedicka Samodien; Maryna de Kock; Elizabeth Joubert; Sonja Swanevelder; Wentzel C. A. Gelderblom. 2020. "Differential Cytotoxicity of Rooibos and Green Tea Extracts against Primary Rat Hepatocytes and Human Liver and Colon Cancer Cells – Causal Role of Major Flavonoids." Nutrition and Cancer , no. : 1-15.

Research article
Published: 17 August 2020 in Phytochemical Analysis
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Introduction The minor phenolic constituents of Cyclopia pubescens Eckl. & Zeyh. are unknown and one dimensional (1D) liquid chromatography (LC) is unable to provide sufficient separation. Methodology A two‐dimensional (2D) LC method incorporating normal‐phasehigh performance countercurrent chromatography (NP‐HPCCC) in the first dimension (1D) and reversed‐phase ultra‐high‐performance liquid chromatography (RP‐UHPLC) as the second dimension (2D) was developed. The analytical HPCCC method was subsequently scaled up to semi‐preparative mode and fractions pooled based on phenolic sub‐groups. The phenolic compounds in selected fractions were subsequently isolated using RP‐HPLC on a C18 column. Isolated compounds were identified by nuclear magnetic resonance (NMR) spectroscopy. The absolute configurations of compounds were determined by optical rotation and electronic circular dichroism spectra. Sugars were identified by gas chromatography‐mass spectrometry (GC–MS) analysis. Results The comprehensive off‐line 2D CCC × LC method gave a good spread of the phenolic compounds. Orthogonality calculated using both the convex hull and conditional entropy methods were 81%. High‐resolution mass spectrometric fragmentation spectra obtained from a quadrupole‐time‐of‐flight instrument and ultraviolet‐visible (UV‐vis) spectral data were used to (tentatively) identify 32 phenolic compounds from the analytical CCC fractions. Of the seven isolated compounds, (2S)‐5‐O‐[α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyl]eriodictyol (3) and (2S)‐5‐O‐[α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyl]‐5,7,3′,4′‐tetrahydroxyflavan (4) were newly identified in all plants. The other isolated compounds were identified as (2S)‐5‐O‐[α‐l‐rhamnopyranosyl‐(1 → 2)‐β‐d‐glucopyranosyl]naringenin (1), R‐neo‐eriocitrin (2), 3‐O‐α‐l‐arabinopyranosyl‐3,4‐dihydroxybenzoic acid (5), 4‐O‐β‐d‐glucopyranosyl‐Z‐4‐hydroxycinnamic acid (6) and 4‐(4′‐O‐β‐d‐glucopyranosyl‐4′‐hydroxy‐3′‐methoxyphenyl)‐2‐butanone (7). Conclusions Among the 32 compounds (tentatively) identified, only six were previously identified in Cyclopia pubescens using 1D LC. Most of the isolated compounds were also identified for the first time in Cyclopia spp., improving the knowledge of the minor phenolic compounds of this genus.

ACS Style

Nico A. Walters; Dalene De Beer; André De Villiers; Ombeline Danton; Matthias Hamburger; Elizabeth Joubert. Comprehensive off‐line CCC × LC‐DAD‐MS separation of Cyclopia pubescens Eckl. & Zeyh. phenolic compounds and structural elucidation of isolated compounds. Phytochemical Analysis 2020, 1 .

AMA Style

Nico A. Walters, Dalene De Beer, André De Villiers, Ombeline Danton, Matthias Hamburger, Elizabeth Joubert. Comprehensive off‐line CCC × LC‐DAD‐MS separation of Cyclopia pubescens Eckl. & Zeyh. phenolic compounds and structural elucidation of isolated compounds. Phytochemical Analysis. 2020; ():1.

Chicago/Turabian Style

Nico A. Walters; Dalene De Beer; André De Villiers; Ombeline Danton; Matthias Hamburger; Elizabeth Joubert. 2020. "Comprehensive off‐line CCC × LC‐DAD‐MS separation of Cyclopia pubescens Eckl. & Zeyh. phenolic compounds and structural elucidation of isolated compounds." Phytochemical Analysis , no. : 1.

Research article
Published: 07 August 2020 in Oxidative Medicine and Cellular Longevity
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Mitochondrial dysfunction plays a major role not only in the pathogenesis of many oxidative stress or age-related diseases such as neurodegenerative as well as mental disorders but also in normal aging. There is evidence that oxidative stress and mitochondrial dysfunction are the most upstream and common events in the pathomechanisms of neurodegeneration. Cyclopia species are endemic South African plants and some have a long tradition of use as herbal tea, known as honeybush tea. Extracts of the tea are gaining more scientific attention due to their phenolic composition. In the present study, we tested not only the in vitro mitochondria-enhancing properties of honeybush extracts under physiological conditions but also their ameliorative properties under oxidative stress situations. Hot water and ethanolic extracts of C. subternata, C. genistoides, and C. longifolia were investigated. Pretreatment of human neuroblastoma SH-SY5Y cells with honeybush extracts, at a concentration range of 0.1-1 ng/ml, had a beneficial effect on bioenergetics as it increased ATP production, respiration, and mitochondrial membrane potential (MMP) after 24 hours under physiological conditions. The aqueous extracts of C. subternata and C. genistoides, in particular, showed a protective effect by rescuing the bioenergetic and mitochondrial deficits under oxidative stress conditions (400 μM H2O2 for 3 hours). These findings indicate that honeybush extracts could constitute candidates for the prevention of oxidative stress with an impact on aging processes and age-related neurodegenerative disorders potentially leading to the development of a condition-specific nutraceutical.

ACS Style

Anastasia Agapouda; Veronika Butterweck; Matthias Hamburger; Dalene De Beer; Elizabeth Joubert; Anne Eckert. Honeybush Extracts (Cyclopia spp.) Rescue Mitochondrial Functions and Bioenergetics against Oxidative Injury. Oxidative Medicine and Cellular Longevity 2020, 2020, 1 -14.

AMA Style

Anastasia Agapouda, Veronika Butterweck, Matthias Hamburger, Dalene De Beer, Elizabeth Joubert, Anne Eckert. Honeybush Extracts (Cyclopia spp.) Rescue Mitochondrial Functions and Bioenergetics against Oxidative Injury. Oxidative Medicine and Cellular Longevity. 2020; 2020 ():1-14.

Chicago/Turabian Style

Anastasia Agapouda; Veronika Butterweck; Matthias Hamburger; Dalene De Beer; Elizabeth Joubert; Anne Eckert. 2020. "Honeybush Extracts (Cyclopia spp.) Rescue Mitochondrial Functions and Bioenergetics against Oxidative Injury." Oxidative Medicine and Cellular Longevity 2020, no. : 1-14.