Impacts of different drying strategies on drying characteristics,the retention of bio-active ingredient and colour changes of dried Roselle

The drying kinetics of Roselle （Hibiscus sabdariffa L） of variety Terengganu （UMKL-1） and the quality attribution of Roselle were studied. The experiments were conducted using four different drying methods, including solar greenhouse drying （SD）, solar greenhouse with intermittent heat pump drying （SIHP）, hot air drying （HA） and heat pump drying （HP）. Among the four drying methods, HP achieved the highest drying rate at a range from 0.054 g H20-（g DM）-1. rain-1 to 0.212 g H20-（g DM）-1. rain 1 while SD had the lowest drying rate, measured at 0.042 g H2O. （g DM） 1.min- 1. The analysis on colour kinetics revealed that there is no significant colour loss （p 〉 0.05） observed from HP＇s dried Roselle. Greater amount of flavonoid compounds i.e. protocatechuic acid was found in SD and SIHP dried finished product whereas HP＇s dried Roselle contains higher percentage of catechin as compared to other drying methods.

Curcumin gum Arabic nanoparticles demonstrate potent antioxidant and cytotoxic properties in human cancer cells

The main purpose of the study was to enhance the stability and therapeutic effects of Curcumin(Cur)through nanoformulation with gum Arabic(GA)as a coating agent through an efficient synthetic approach.The antioxidant properties of the developed nanoparticles(Cur/GANPs)were assessed through several in vitro assays,such asβ-carotene bleaching activity,DPPH,and nitric oxide scavenging activities in addition to evaluating its inhibitory activity on angiotensinconverting enzyme(ACE).The cytotoxicity of Cur/GANPs was evaluated in vitro using different types of human cancer cells including breast cancer(MCF7,MDA-MB231),liver cancer(HepG2),and colon cancer(HT29)cells.The prepared particles displayed an elliptical shape with a size ranging between 20–260 nm and a potential difference of–15 mV.The Cur/GANPs exhibited significant antioxidant activity compared to free curcumin when using concentrations between 31.5 and 500μg/mL.The Cur/GANPs also had inhibited the growth of all cancer cell lines in a proportional trend with concentrations used.Hence,the encapsulation with gum Arabic has augmented the antioxidant and anti-neoplastic effects of Curcumin.Therefore,Cur/GANPs may have effective therapeutic properties in diseases attributed to oxidative stress like cancer and hypertension.

Low Temperature Growth of Vertically Aligned Carbon Nanotubes via Floating Catalyst Chemical Vapor Deposition Method

Synthesis of carbon nanotubes （CNTs） below 600℃ using supporting catalyst chemical vapor deposition method was reported by many research groups. However, the floating catalyst chemical vapor deposition received less attention due to imperfect nanotubes produced. In this work, the effects of varying the preheating temperature on the synthesis of CNT were investigated. The reaction temperature was set at 570℃. The preheating set temperature was varied from 150 to 400℃ at 50℃ interval. Three O-ring shape heating mantels were used as heating source for the preheater. In situ monitoring device was used to observe the temperature profile in the reactor. Benzene and ferrocene were used as the carbon source and catalyst precursor, respectively. Vertically aligned CNTs were synthesized when the preheating temperature was set at 400℃. When the preheating temperature was increased up to 400℃, both the length and the alignment of CNTs produced were improved.

Effects of temperature and solvent concentration on the solvent crystallization of palm-based dihydroxystearic acid with isopropyl alcohol

Palm-based dihydroxystearic acid of 69.55% purity was produced in a 500-kg-per-batch operation pilot plant and purified through solvent crystallization in a custom fabricated simultaneous batch crystallizer unit. The effects of temperature and solvent concentration on yield, particle size distribution and purity were studied. The purity was higher, while the yield and particle size were lower and smaller, respectively, at higher temperature and solvent concentration. The solvent crystallization process efficiency was rated at 66-69% when carried out with 70-80% isopropyl alcohol at 20℃.