Impact of Roasting to Total Phenolic, Flavonoid and Antioxidant Activities in Root, Bark and Leaf of Polyscias fruticosa

Polyscias fruticosabelongs to Araliaceae family widely cultivated in Vietnam. It is a medical plant highly valued recently owing to its diversified therapeutic functions. It’s exploited in all parts includingroot, bark and leaf for medicinal purposes. In the herbal tea production, the final step is normally ended with the roasting in order to improve its flavor and aroma. There’s a concern about the detrimental effect of thermal roasting to the stability of phytochemical constituents. In this research, we attempted to evaluate the reduction of total phenolic (mg GAE/100 g), total flavonoid (mg QE/100 g), DPPH radical-scavenging ability (mM TE/100 g), FRAP ferric reducing antioxidant power assay (mM TE/100 g) in root, bark and leaf of Polyscias fruticosa under different roasting conditions. All samples were steamed in vapor for 30 seconds before being dried by convective dryer at 45C for 6 hours to final moisture content around 12%. Then these samples would be roasted in different conditions (125/15; 130/12, 135/9, 140/6, 145/3, C/minutes). Our results revealed that roasting at 135/9C/minutes was appropriate to preserve the most phytochemical constituents

Mircowave-Assisted Extraction of Phytochemical Constituents in Roselle (Hibiscus sabdariffa L.)

Roselle (Hibiscus sabdariffaL.) is natural source of valuable components such as phenolics, flavonoids and anthocyanins. Anthocyaninis normally used in the food technology to replace synthetic pigments as well as medicinal properties due to antioxidants. Microwave irradiation is a feasible green solvent extraction method receiving great attention as it utilizes solvent at elevated temperature and controlled pressure conditions. Microwave extraction emerges as a promising inexpensive, simple and efficient technique. In our research, various variable like microwave power (20, 40, 60, 80, 100 W), microwave frequency (10, 20, 30, 40, 50 GHz), the micrwave irradiation duration (5, 10, 15, 20, 25 min), liquid to solid ratio (water: material, 2:1, 3:1, 4:1, 5:1, 6:1), extraction temperature (50, 55, 60, 65, 70C), number of extraction cycles (1, 2, 3, 4, 5) influencing to the microwave-assisted extraction of phytochemicals in roselle (Hibiscus sabdariffa L.)calyx were thoroughly examined. Total total phenolic (mg GAE/ 100g), total flavonoid (mg GE/ 100g), anthocyanin (mg/100g) were key indicators to define the optimal variable. Our resultsrevealed that microwave power at 80 W, frequency 40 GHz, duration 15 min, liquid to solid ratio 4:1, temperature 55C, 4 cycles of extraction were appropriate for extraction of phytochemical components inside roselle (Hibiscus sabdariffa L.)calyx

Degradation of Phytochemical and Antioxidant Capacity of Noni (Morinda Citrifolia L.) Pulp Tea during Drying and Roasting Treatment

Noni (Morinda citrifolia L.) fruitis highly evaluated asan important herb with a good source of natural antioxidant against various ailments as well as maintain overall good health. It’s normally disposed due to unpleasant aroma from the ripened fruit. There is limited literature mentioned to the decomposition of this valuable fruit during thermal processing. Hence this reseach aimed to evaluate the possible degradation of total phenolic (mg GAE/100 g), total flavonoid (mg QE/100 g), DPPH radical-scavenging ability (mM TE/100 g), FRAP ferric reducing antioxidantpower assay (mM TE/100 g) in raw, dried and roasted noni pulp tea. The highest contents of functional constituents and antioxidant capacity were noticed in the raw sample; meanwhile decreased dramatically in the roasted one. However, degradation of noni flavonol glycosides during roasting could produce aglycone metabolites, which in turn, may lead to increased bioavailability. Owing to degradation of phytochemical and antioxidant ability by harsh thermal treatment, it’s necessary to be careful in drying and roasting to limit detrimental effect in herbal noni tea production

Synergistic Effect of Acoustic and Vacuum Drying to Antioxidant Attributes of Cordyceps militaris

Acoustic drying allows the utilization of lower temperatures than conventional methodology in the drying process.Vacuum drying is one of the most energy demanding processes. Water evaporation also takes place at lower temperatures under vacuumand hence the product processing temperature can be significantly lower, offering higher product quality. Cordyceps militarisis a well-known entamophagus fungus with wonderful health benefits such as adaptogenic, aphrodisiac, anti-oxidant, anti-aging, neuroprotective, nootropic, immunomodulatory, anti-cancer and hepatoprotective role by its phytochemical constituents. This study focused on the synergistic effects of acoustic and vacuum drying on antioxidant properties of Cordyceps militaris. We noticed that acoustic drying at power 800 W in frequency 40kHz combined with vacuum drying at pressure -0.8 bar were suitable for dehydration of this valuable material. From this approach, a combination of acoustic and vacuum drying created a synergistic effect consuming less energy than single drying method because it can be performed at low temperature while maintaining the product quality and wholesomeness. Moisture content is partly removed by acoustic drying and further dehydration in a vacuum dryer to reduce moisture to a stable level