ANTIOXIDANT POTENTIAL OF MALAYSIAN FRUIT EXTRACT (MYRISTICA FRAGRANS)

The aim of this experiment is to study the phytochemical content of Malaysian fruit (Myristica fragrans), commonly known as nutmeg. This study also includes the optimization of extraction conditions for both soxhlet and ultrasonic extraction to yield the highest total phenolic content, total flavonoid content and 2, 2-diphenyl picryl hydrazyl scavenging activity of nutmegs using Response surface methodology. Soxhlet extraction is carried out with different extraction time and type of solvent. However, ultrasonic-assisted extraction is carried out with different extraction time, concentration of solvent and temperature of ultrasonic water bath. It has been shown that the optimum value of total phenolic content, total flavonoid content and 2, 2-diphenyl picryl hydrazyl scavenging activity of soxhlet extraction on nutmegs are 12.290 mg, 17.09 mg and 95.837%, respectively with a desirability of 0.671. The optimum condition for soxhlet extraction of nutmegs to obtain optimum yield of total phenolic content, total flavonoid content and 2, 2-diphenyl picryl hydrazyl scavenging are by using methanol as solvent at 184 minutes extraction time. However, for the optimization value of total phenolic content, total flavonoid content and 2, 2- diphenyl picryl hydrazyl scavenging activity for ultrasonic- assisted extraction of nutmegs are 28.722 mg, 46.600 mg and 98.565%, respectively with a desirability of 0.977. The optimum condition for ultrasonic assisted extraction of nutmegs to obtain optimum yield of total phenolic content, total flavonoid content and 2, 2- diphenyl picryl hydrazyl scavenging are by extracting nutmeg at 40 minutes at 50 ℃ and at 40% ethanol concentration

REVIEW ON PRODUCTION OF BENZENE FROM PETROLEUM ASSOCIATED GAS BY DEHYDROAROMATIZATION, PARTIAL OXIDATION OF METHANE AND METHANOL-TO-AROMATICS PROCESSES

Benzene is the most basic aromatic compound, which possesses diverse applications in the chemical industry. Benzene is mainly used as an intermediate chemical for styrene in the manufacturing of plastic materials. The benzene derivatives such as styrene, cumene, cyclohexane and nitrobenzene are the four most significant products, which are highly dependent on the benzene demand. However, there is a huge gap between the supply and demand of benzene, and fluctuation of the market price of benzene is also noticeable in recent years. Primarily, benzene is produced as a by-product especially from steam crackers, production of p-xylene and also in oil refineries. This caused the demand of benzene to follow strictly on gasoline, ethylene and also p-xylene in particular. Hence, in this review, three important benzene process pathways are studied and compared based on its economic, safety and environmental aspects in order to allow researchers to understand and able to compare different route of benzene production in terms of sustainability aspects for an on-purpose build of a benzene production plant, which is more economically viable. Three identified process are benzene from ethane (ETB), methane dehydroaromatization: Non-oxidative process (NO-MDA) and natural gas via Methanol synthesis (MTB). NO-MDA process was found to be the most sustainable process among the above. The processes are based on the decision matrix method

FRACTIONATION OF HYDROLYZED MICROCRYSTALLINE CELLULOSE BY ULTRAFILTRATION MEMBRANE

Bioethanol process using cellulosic materials have been emerging an interesting field with a high potential of replacing petroleum-based fuel, as a future alternative. This work emphasised on improvement of enzymatic hydrolysis of alkaline NaOH-pretreated cellulose by applying an ultrafiltration membrane 10 kDa cutoff in order to minimise sugar inhibition on enzymes, reuse enzyme in hydrolysis and recover sugar for the subsequent fermentation. An improvement in the methodology of the enzymatic hydrolysis with ultrafiltration was made that the membrane was installed at the end of a tube connecting with a peristaltic pump to continuously remove glucose from hydrolysis reaction hence sugar was unable to inhibit enzyme activity and enzyme was retained inside the reactor for the reusing purpose. The combination of NaOH 1M alkaline pretreatment, enzymatic hydrolysis of cellulose with the optimum 3% enzyme dosage, ultrafiltration 10 kDa cutoff was evaluated to obtain the highest sugar concentration at 9 mg/ml after 6 hour hydrolysis. In comparison between hydrolysis with ultrafiltration and hydrolysis without ultrafiltration, the sugar concentration in hydrolysis with ultrafiltration was very much higher than that in hydrolysis without ultrafiltration in all enzyme dosages (1.5%, 3%, 6%). The hydrolysis with filtration produced a time profile in six hours with continuously significant increase in the sugar concentration. Only a small reduction initially for 1.5% dosage and no reduction in sugar concentration in 3% and 6% dosages. Hence the effect of product inhibition in hydrolysis was minimised as a result. In addition, a direct relationship between sugar concentration inside hydrolysis reactor, enzyme dosage and rate of sugar removal was observed during the hydrolysis process. Higher enzyme dosage in hydrolysis required a higher rate of sugar removal sufficiently to avoid inhibition in hydrolysis reaction

A REVIEW ON USING MEMBRANE REACTORS IN ENZYMATIC HYDROLYSIS OF CELLULOSE

Enzymatic hydrolysis of cellulose in the conventional batch reactors is severely affected by product inhibition due to the accumulation of glucose inside. The approach of using ultrafiltration membranes has created an effective way for simultaneously glucose removal and enzyme recovery with two main configurations of membrane reactors developed by many researchers. This short review aims at examining the main features of external loop and submerged membrane reactors, i.e. its operation conditions such as substrate concentration, enzyme to substrate ratio, and mixing which affect the performance of hydrolysis in term of conversion, glucose formation, concentration polarisation and fouling. Challenges of membrane reactors were realised as low output glucose concentration, unsuitable to run at high cellulose concentrations, and the total recovery of enzymes adsorbed in the solid cellulose and liquid hydrolysate. Besides that, other two new configurations (dialysis and the modified membrane reactor) are highlighted as very potential methods to not only effectively remove glucose for minimising product inhibition and recover enzymes but also able to handle higher cellulose concentrations form 10% or higher. Further research should focus on the degree of glucose removal from hydrolysis reaction membrane reactor systems, and operational feasibility in disposal of unconverted substrate after hydrolysis

Optimisation of spray drying operating conditions of Morinda citrifolia L. fruit extract using response surface methodology

A conventional solvent extract of Morinda citrifolia L. fruit was spray dried using adjuvant maltodextrin (5 wt.%). Spray drying was carried out according to the D-optimal design, and the independent variables selected were temperature and Mcore/Mwall. The spray drying process was optimised by using response surface methodology (RSM) for four different responses: moisture content (MC), DPPH scavenging activity, total phenolic content (TPC), and total flavonoid (TF). The effects of temperature and of the core to wall material ratio were found to be significant for all responses. The optimal spray drying condition for maltodextrin as binding material was found to be 1:1.5 (Mcore/Mwall, volume ratio of M. citrifolia L. extract to additive solution) at 95 °C. The experimental values of the response variables correspond well to the predicted values. The microparticles obtained in this study represent an interesting food additive for incorporation into functional foods due to the presence of antioxidants