|2015||Vuong QV, Zammit N, Munro BR, Murchie S, Bowyer MC, Scarlett CJ, 'Effect of Drying Conditions on Physicochemical and Antioxidant Properties of V itex Agnus-Castus Leaves', Journal of Food Processing and Preservation, n/a-n/a (2015)|
|2015||Nguyen VT, Vuong QV, Bowyer MC, Altena IAV, Scarlett CJ, 'Effects of Different Drying Methods on Bioactive Compound Yield and Antioxidant Capacity of Phyllanthus amarus', Drying Technology, 150211123721006-150211123721006 (2015)|
|2015||Vuong QV, Van TN, Dang TT, Bhuyan DJ, Goldsmith CD, Sadeqzadeh E, et al., 'Optimization of ultrasound-assisted extraction conditions for euphol from the medicinal plant, Euphorbia tirucalli, using response surface methodology', INDUSTRIAL CROPS AND PRODUCTS, 63 197-202 (2015)|
|2015||Nguyen VT, Bowyer MC, Vuong QV, Altena IA, Scarlett CJ, 'Phytochemicals and antioxidant capacity of Xao tam phan (Paramignya trimera) root as affected by various solvents and extraction methods', Industrial Crops and Products, 67 192-200 (2015)|
Xao tam phan (. Paramignya trimera (Oliv.) Guillaum) is a Vietnamese traditionally medicinal plant used in the treatment of numerous cancers. The preparation of Xao tam phan extracts including solvent type and extraction method have significant effects on extraction efficiency, phytochemical profile and biological activity. This study aimed to investigate the effects of five various solvents (water, acetonitrile, methanol, ethyl acetate and hexane) and three different extraction methods (conventional, ultrasound-assisted and microwave-assisted) on phytochemical yield and antioxidant capacity of P. trimera root from Vietnam. The results indicate that methanol extracted the maximal yield of phytochemicals from P. trimera and exhibited the greatest antioxidant capacity, with eleven compounds were identified and quantified. Microwave-assisted extraction produced the maximal phytochemical yields (except for total flavonoids) and antioxidant capacity, when compared to conventional and ultrasound-assisted extractions. These data reveal that the use of methanol and microwave-assisted extraction are recommended for extraction of biologically active phytochemicals from P. trimera root for application in the nutraceutical and/or pharmaceutical industries.
|2015||Vuong QV, Hirun S, Chuen TLK, Goldsmith CD, Murchie S, Bowyer MC, et al., 'Antioxidant and anticancer capacity of saponin-enriched Carica papaya leaf extracts', International Journal of Food Science and Technology, 50 169-177 (2015)|
Summary: The papaya (Carica papaya) leaf (PL) contains high levels of saponins and polyphenolic compounds, and historically, it has been used as a folk medicine for numerous ailments, including cancer. PL is traditionally prepared by hot water extraction; however, optimised extraction conditions have not been assessed. This study optimised conditions for the extraction of saponins from PL and assessed their antioxidant capacity and antipancreatic cancer activity. Optimisation was achieved using response surface methodology. Saponins and total phenolic compounds were assessed for their antioxidant, free radical scavenging, ion-reducing capacity, and antipancreatic cancer activity. Optimal aqueous extraction conditions were 85 Â°C, 25 min. and a water-to-leaf ratio of 20:1 mL g-1. Ethanol extracts demonstrated higher antioxidant, free radical scavenging and ion-reducing capacity, as well as antipancreatic cancer activity. This study revealed that the PL contains numerous bioactive compounds, with significant anticancer activity warranting further studies on the isolation and characterisation of individual bioactive compounds from the PL.
|2015||Vuong QV, Hirun S, Chuen TLK, Goldsmith CD, Munro B, Bowyer MC, et al., 'Physicochemical, antioxidant and anti-cancer activity of a Eucalyptus robusta (Sm.) leaf aqueous extract', INDUSTRIAL CROPS AND PRODUCTS, 64 167-174 (2015)|
|2015||Vuong QV, Hirun S, Chuen TLK, Goldsmith CD, Murchie S, Bowyer MC, et al., 'Antioxidant and anticancer capacity of saponin-enriched Carica papaya leaf extracts', INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY, 50 169-177 (2015)|
|2015||Hirun S, Choi J-H, Ayarungsaritkul J, Pawsaut C, Sutthiwanjampa C, Vuong QV, et al., 'Optimization of far-infrared vacuum drying conditions for Miang leaves (Camellia sinensis var. assamica) using response surface methodology', Food Science and Biotechnology, 24 461-469 (2015)|
Far-infrared (FIR) vacuum is an advanced drying technique that has recently been applied in food processing. Optimal drying conditions for processing tea from Miang leaves using FIR vacuum drying were investigated. Response surface methodology with a central composite design was used to design, analyze, and predict the optimal time and temperature conditions for FIR vacuum drying, taking into account the physicochemical properties of Miang leaves. When the temperature increased from 50 to 65Â°C and the time from 60 to 120 min, the amount of epicatechin, epicatechin gallate, epigallocatechin gallate, and total catechins significantly (p<0.05) increased while the moisture content and water activity significantly (p<0.05) decreased, compared with controls. The physicochemical properties of dried Miang leaves were significantly (p>0.05) influenced by time and temperature, compared with controls. Drying conditions of 65Â°C for 120 min are recommended for optimization of drying.
|2015||Bhuyan DJ, Quan VV, Chalmers AC, van Altena IA, Bowyer MC, Scarlett CJ, 'Microwave-assisted extraction of Eucalyptus robusta leaf for the optimal yield of total phenolic compounds', INDUSTRIAL CROPS AND PRODUCTS, 69 290-299 (2015)|
|2015||Nguyen VT, Van Vuong Q, Bowyer MC, Van Altena IA, Scarlett CJ, 'Effects of Different Drying Methods on Bioactive Compound Yield and Antioxidant Capacity of Phyllanthus amarus', Drying Technology, 33 1006-1017 (2015)|
Phyllanthus amarus (P. amarus) has been used as a herbal medicine, particularly for liver support, in many countries and its extracts have been shown to possess potent antioxidant and anticancer properties in vitro. The preparation of dried sample is crucial for further extraction and isolation of phytochemicals. In this study, the effects of six different drying methods (hot air, low-temperature air, infrared, microwave, sun, and vacuum drying) on the phytochemical yield and antioxidant capacity were determined to identify the optimal drying method for P. amarus. The results showed that different drying methods, as well as different drying conditions within each method, significantly affected phytochemical yield and antioxidant capacity of P. amarus extracts. Infrared drying at 30Â°C was the best method for both retention of bioactive compound yield and antioxidant capacity of P. amarus extract, with 12 compounds were identified. In contrast, low-temperature-air drying at 25Â°C not only required the longest drying time but also significantly reduced the levels of bioactive compounds and antioxidant capacity of P. amarus. Therefore, infrared drying at 30Â°C is suggested for drying P. amarus for subsequent assessment of bioactivity.
|2015||Vuong QV, Zammit N, Munro BR, Murchie S, Bowyer MC, Scarlett CJ, 'Effect of drying conditions on physicochemical and antioxidant properties of vitex agnus-castus leaves', Journal of Food Processing and Preservation, (2015)|
Vitex agnus-castus (VitexAC) leaves have been used for medicinal purposes for many years. Drying is important to prepare starting materials for further processing, as it is associated with production cost and quality of the materials. Herein, the effects of five different drying conditions on the physical, chemical and antioxidant properties of VitexAC were evaluated. The results showed that 30% of dried leaves with moisture content of less than 7% could be produced from fresh leaves. VitexAC leaves dried by freeze and vacuum drying at 65C had higher levels of bioactive compounds as well as higher antioxidant capacity in comparison with other drying conditions, revealing that these drying conditions are more suitable for drying VitexAC leaves. However, freeze drying is costly and time-consuming; thus, vacuum drying at 65C is suggested for drying the VitexAC leaves as the starting materials for further processing steps. Practical Applications: As drying is an important process to prepare starting materials for further processing steps, it is important to compare different drying methods to identify the most suitable method with low cost and less effect on material quality. The results showed that inappropriate drying conditions resulted in big loss of bioactive compounds and antioxidant capacity. Vacuum drying at 65C was found to be the most suitable method, which can be easily applied for drying Vitex agnus-castus leaves in the industrial scale.
|2015||Vuong QV, Chalmers AC, Jyoti Bhuyan D, Bowyer MC, Scarlett CJ, 'Botanical, Phytochemical, and Anticancer Properties of the Eucalyptus Species.', Chem Biodivers, 12 907-924 (2015)|
|2014||Tan SP, Vuong QV, Stathopoulos CE, Parks SE, Roach PD, 'Optimized Aqueous Extraction of Saponins from Bitter Melon for Production of a Saponin-Enriched Bitter Melon Powder', Journal of Food Science, 79 (2014) [C1]|
Bitter melon, Momordica charantia L. (Cucurbitaceae), aqueous extracts are proposed to have health-promoting properties due to their content of saponins and their antioxidant activity. However, the optimal conditions for the aqueous extraction of saponins from bitter melon and the effects of spray drying have not been established. Therefore, this study aimed to optimize the aqueous extraction of the saponins from bitter melon, using response surface methodology, prepare a powder using spray drying, and compare the powder's physical properties, components, and antioxidant capacity with aqueous and ethanol freeze-dried bitter melon powders and a commercial powder. The optimal aqueous extraction conditions were determined to be 40 Â°C for 15 min and the water-to-sample ratio was chosen to be 20:1 mL/g. For many of its physical properties, components, and antioxidant capacity, the aqueous spray-dried powder was comparable to the aqueous and ethanol freeze-dried bitter melon powders and the commercial powder. The optimal conditions for the aqueous extraction of saponins from bitter melon followed by spray drying gave a high quality powder in terms of saponins and antioxidant activity. Â© 2014 Institute of Food TechnologistsÂ®.
|2014||Vuong QV, Hirun S, Phillips PA, Chuen TLK, Bowyer MC, Goldsmith CD, Scarlett CJ, 'Fruit-derived phenolic compounds and pancreatic cancer: Perspectives from Australian native fruits', JOURNAL OF ETHNOPHARMACOLOGY, 152 227-242 (2014) [C1]|
|2014||Hirun S, Utama-ang N, Vuong QV, Scarlett CJ, 'Investigating the Commercial Microwave Vacuum Drying Conditions on Physicochemical Properties and Radical Scavenging Ability of Thai Green Tea', DRYING TECHNOLOGY, 32 47-54 (2014) [C1]|
|2014||Vuong QV, 'Epidemiological Evidence Linking Tea Consumption to Human Health: A Review', Critical Reviews in Food Science and Nutrition, 54 523-536 (2014) [C1]|
Tea has been widely consumed around the world for thousands of years and drinking tea is a daily habit for people of all ages. Tea is a major source of flavanoids, which have become well known as antioxidants. Tea also contains caffeine and theanine, which have been found to associate with health benefits. Many animal and epidemiological studies have been conducted to investigate the link between tea consumption and human health. However, common questions that arise about tea consumption include: whether all teas are the same, why drinking tea is linked with health benefits, how do the different ways of tea preparation impact on availability of tea components, how much and how long a person should consume tea to obtain health benefits, and whether there is any negative health effect associated with drinking tea. To answer these questions, this paper outlines the tea components and their link to human health, discusses major factors affecting availability of tea components in a tea cup, and reviews the latest epidemiological evidence linking tea consumption to human health. Â© 2014 Copyright Taylor and Francis Group, LLC.
|2014||Vuong QV, Roach PD, 'Caffeine in Green Tea: Its Removal and Isolation', SEPARATION AND PURIFICATION REVIEWS, 43 155-174 (2014) [C1]|
|2014||Vuong QV, Sadeqzadeh E, Hirun S, Goldsmith CD, Zammitt N, Bowyer MB, et al., 'Phenolic Compounds, Antioxidant and Anti-Cancer Properties of the Australian Maroon Bush Scaevola spinescens (Goodeniaceae)', Journal of Bioanalysis & Biomedicine, S12 (2014) [C1]|
|2014||Vuong QV, Hirun S, Chuen TLK, Goldsmith CD, Bowyer MC, Chalmers AC, et al., 'Physicochemical composition, antioxidant and anti-proliferative capacity of a lilly pilly (Syzygium paniculatum) extract', Journal of Herbal Medicine, 4 134-140 (2014) [C1]|
Lilly pilly (LP) fruit (Syzygium paniculatum Gaertn.) is widely grown in eastern Australia and has been used as food by indigenous Australians. However, there is limited information on its bioactivity. This study investigated the physicochemical and antioxidant properties of the crude fruit extract, identified its bioactive compounds and also assessed its potential anti-proliferative effect on pancreatic cancer cells. Our data showed that the LP extract was water-soluble and possessed a total phenolic content of 96 mg of gallic acid equivalents (GAE)/g, flavonoid levels of 52 mg catechin equivalents (CAE)/g, proanthocyanidin levels of 29 mg CAE/g. Several phenolic compounds such as gallic acid, chlorogenic acid, catechin and epicatechin were identified in the LP extract with levels of 0.39, 2.35, 0.47 and 2.9 mg/g, respectively. Results from six different antioxidant assays revealed that the LP extract pocessed potent antioxidant and free radical scavenging capacity. Although antioxidant capacity of the extract was lower than that of vitamin E, vitamin C and BHT, it could be significantly improved if the extract was to be further purified. We also showed that the LP extract (200 Âµg/mL) significantly reduced the viability of MiaPaCa-2 and ASPC-1 pancreatic cancer cells to levels comparable to that of the chemotherapeutic agent gemcitabine. For this reason lilly pilly should be further investigated for its health promoting and potential anti-cancer benefits, particularly for pancreatic cancer. Â© 2014 Elsevier GmbH.
|2014||Goldsmith C, Vuong Q, Stathopoulos C, Roach P, Scarlett C, 'Optimization of the Aqueous Extraction of Phenolic Compounds from Olive Leaves', Antioxidants, 3 700-712 (2014) [C1]|
|2014||Vuong Q, Goldsmith C, Dang T, Nguyen V, Bhuyan D, Sadeqzadeh E, et al., 'Optimisation of Ultrasound-Assisted Extraction Conditions for Phenolic Content and Antioxidant Capacity from Euphorbia tirucalli Using Response Surface Methodology', Antioxidants, 3 604-617 (2014) [C1]|
|2013||Vuong QV, Golding JB, Nguyen MH, Roach PD, 'Preparation of decaffeinated and high caffeine powders from green tea', Powder Technology, 233 169-175 (2013) [C1]|
The aims of this study were to develop optimal conditions for decaffeination and spray drying procedures to produce decaffeinated and high caffeine powders from green tea (Camellia sinensis). Blanching the tea leaves with water at 100. Â°C for 4. min at a water-to-tea ratio of 20:1. mL/g removed 83% of the caffeine while retaining 94% of the catechins. The optimal spray drying conditions, which gave the highest yield of green tea powder and the highest concentrations of the naturally occurring epistructured catechins were found to be 180. Â°C for the inlet temperature and 115. Â°C for the outlet temperature. Using these optimal conditions, a decaffeinated green tea powder (7 mg/g caffeine) and a high caffeine powder (95. mg/g) were produced. These two green tea powders had excellent physical properties and could be used as instant teas by consumers or utilized in the food, cosmetic and nutraceutical industries. Â© 2012 Elsevier B.V.
|2013||Vuong QV, Golding JB, Stathopoulos CE, Roach PD, 'Effects of aqueous brewing solution pH on the extraction of the major green tea constituents', Food Research International, 53 713-719 (2013) [C1]|
The pH of the aqueous brewing solution was maintained at values ranging from 1 to 9 during the green tea extraction and the effects on the tea's extracted constituents were studied. The epistructured catechins were stable under acidic conditions but epimerized or degraded at pH. =. 6. The extractable solids contained more epistructured catechins at pHs 3-5 but more non-epistructured catechins at pHs 6-7. More tea cream was obtained at pH 1 but the concentration of catechins, caffeine and theanine was low in this fraction. Therefore, to maximize the extraction of the epistructured catechins and to minimize their epimerization and degradation and to maximize the extraction of caffeine and theanine, the results suggest that the pH should be maintained between 3 and 5.3 during the aqueous brewing process. Â© 2012 Elsevier Ltd.
|2013||Vuong QV, Hirun S, Roach PD, Bowyer MC, Phillips PA, Scarlett CJ, 'Effect of extraction conditions on total phenolic compounds and antioxidant activities of Carica papaya leaf aqueous extracts', JOURNAL OF HERBAL MEDICINE, 3 104-111 (2013) [C1]|
|2012||Vuong QV, Golding J, Nguyen MH, Roach PD, 'Production of caffeinated and decaffeinated green tea catechin powders from underutilised old tea leaves', Journal of Food Engineering, 110 1-8 (2012) [C1]|
|2012||Vuong QV, Tan SP, Stathopoulos C, Roach PD, 'Improved extraction of green tea components from teabags using the microwave oven', Journal of Food Composition and Analysis, 27 95-101 (2012) [C1]|
|2011||Vuong QV, Stathopoulos C, Golding J, Nguyen MH, Roach PD, 'Optimum conditions for the water extraction of L -theanine from green tea', Journal of Separation Science, 34 2468-2474 (2011) [C1]|| |
|2011||Vuong QV, Golding J, Stathopoulos C, Nguyen MH, Roach PD, 'Optimizing conditions for the extraction of catechins from green tea using hot water', Journal of Separation Science, 34 3099-3106 (2011) [C1]|| |
|2011||Vuong QV, Nguyen V, Golding J, Roach PD, 'The content of bioactive constituents as a quality index for Vietnamese teas', International Food Research Journal, 18 329-336 (2011) [C1]|| |
|2011||Vuong QV, Durel M, Roach PD, Stathopoulos C, 'Preliminary study on the fortification of tofu with green tea catechins', International Food Research Journal, 18 1553-1557 (2011) [C1]|| |
|2011||Vuong QV, Stathopoulos C, Nguyen MH, Golding J, Roach PD, 'Isolation of green tea catechins and their utilization in the food industry', Food Reviews International, 27 227-247 (2011) [C1]|| |
|2011||Vuong QV, Bowyer MC, Roach PD, 'L-Theanine: Properties, synthesis and isolation from tea', Journal of the Science of Food and Agriculture, 91 1931-1939 (2011) [C1]|
|2010||Vuong QV, Golding J, Nguyen MH, Roach PD, 'Extraction and isolation of catechins from tea', Journal of Separation Science, 33 3415-3428 (2010) [C1]|| |