https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47992 Leptospermum petersonii is an aromatic native Australian plant that has been traditionally used as a medicine and a tea; however, its application in food products is increasing. The aim of this study was to investigate the most suitable and energy-efficient drying conditions to retain phenolic compounds, antioxidant properties, and, color in dried Leptospermum petersonii leaves. In this study, six drying techniques were investigated including hot air, vacuum, microwave, freeze, sun, and shade. Results showed that freeze-drying retained maximum color, phenolic compounds, and, antioxidant capacity, however, it consumed the most time and energy. Conversely, microwave drying (960 W, 0.1 hr) used the least amount of time and energy yet retained the second-highest levels of phenolics and antioxidant capacity. In conclusion, microwave drying is suggested for large-scale drying. This method is economical and it is approximately 480 times and 1,700 times more time and energy efficient compared to freeze-drying.]]> Tue 14 Feb 2023 15:04:58 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49461 Thu 18 May 2023 12:40:14 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34478 Catharanthus roseus (L.) G. Don (C. roseus) is well known as an important medicinal plant, with compounds such as the vinca alkaloids isolated for their anticancer activity. As such, it is important to determine the effective solvent for bioactive compound extraction from this plant and the suitable drying methods for preparation of starting material. The aims of this study were to determine the effect of extraction solvents and drying methods on bioactive compounds and antioxidant properties of C. roseus. Water was found to be the optimal solvent for phenolic and flavonoid extraction; whereas, methanol was the best solvent for saponin and proanthocyanidin extraction. The data also revealed that vacuum drying at 50°C was suitable for drying the leaf and the flower which contained high levels of phenolics and flavonoids, while infrared drying at 35°C was recommended for drying the stem and the root which had high saponin content. Practical applications: This study suggested that different parts of C. roseus had different suitable thermal drying methods. For the leaf and the flower, vacuum drying at 50°C was the optimal drying method, whereas infrared drying at 35°C was suitable for drying the stem and the root. These drying conditions can be easily applied for preparation of dried plant parts with high levels of bioactive compounds in the large scale. Importantly, the data indicated that the stem and the root of C. roseus which were considered as waste when the leaf was used for exploiting alkaloids, possessed great content of saponins. Therefore, these parts can be further used for isolation and purification of saponins.]]> Fri 03 Dec 2021 10:35:25 AEDT ]]>