Optimization of Cellulose Nanocrystal Isolation from Ayous Sawdust Using Response Surface Methodology

This study focuses on the extraction of cellulose nanocrystals (CNC), from microcrystalline cellulose (MCC), derived from Ayous sawdust. The process involves multiple steps and a large amount of chemical products. The objective of this research was to determine the effects of factors that impact the isolation process and to identify the optimal conditions for CNC isolation by using the response surface methodology. The factors that varied during the process were the quantity of MCC, the concentration of sulfuric acid, the hydrolysis time and temperature, and the ultrasonic treatment time. The response measured was the yield. The study found that with 5.80 g of microcrystalline cellulose, a sulfuric acid concentration of 63.50% (w/w), a hydrolysis time of 53 minutes, a hydrolysis temperature of 69˚C, and a sonication time of 19 minutes are the ideal conditions for isolation. The experimental yield achieved was (37.84 ± 0.99) %. The main factors influencing the process were the sulfuric acid concentration, hydrolysis time and temperature, with a significant influence (p < 0.05). Infrared characterization results showed that nanocrystals were indeed isolated. With a crystallinity of 35.23 and 79.74, respectively, for Ayous wood fiber and nanocrystalline cellulose were observed by X-ray diffraction, with the formation of type II cellulose, thermodynamically more stable than native cellulose type I.

A Field Survey to Assess the Consumption of <i>Nkang</i>for Standardization and Valorization in the North-West Region of Cameroon

In African communities, traditional beer drinking remains a unifying factor within its populations both socially, commercially, culturally, politically, in health and nutrition and for some ritual practices. In this research a field survey was carried out to investigate the consumption of corn beer and in particular Nkang in the North-West Region of Cameroon. The tools that were employed to carry out these investigations included face-to-face interviews and the use of properly designed questionnaires. Results from the survey showed that three types of maize-based beverages are drunk in the North-West Region of Cameroon, which are locally called Kwacha (whitish, most viscous and most turbid), Sha-ah (cream white, viscous and turbid) and Nkang (dark brown, least viscous and least turbid) in terms of colour, viscosity and turbidity. The percentage awareness of the existence of these beers from the sampled population gave the following values;60.9% for Kwacha, 100% for Sha-ah and 89.1% for Nkang. Nonetheless, 54.5% of the 60.9% of those who were aware of the existence of kwacha had at least tasted it. Also 98.2% out of the 100% for Sha-ah and 85.5% out of 89.1% for Nkang had tasted them, too. Nkang was found to be the most preferred to Sha-ah then Kwacha in that order by the consumers since Nkang is very tasteful, least alcoholic, least turbid, least viscous, has the most attractive colour than the others, has a significant impact on the culture of some localities in this region and as well as it is natural and nutritious. However, Nkang as well as the other two has varying organoleptic properties, unsatisfactory conservation and short shelf-life. Hence are consumed within a short period of time from their production. Because of the low alcoholic content of Nkang, the beverage is consumed by both adults (most elderly), children, those who have health problems and it is mostly preferred by some Christians though not frequently seen in the markets. It was equally observed that the little quantity of Nkang found in the markets is of poor quality which keeps dropping everyday thus an indication of its risk becoming extinct. Therefore, if Nkang is clarified and its quality improved, the problems can be solved as even attested by the consumers who say they will buy at even a higher price if clarify. As well as those who want it for their cultural reasons do not want it to face out too.

A Valorized Scheme for Failure Prediction Using ANFIS: Application to Train Track Breaking System

In the rolling stock sector, the ability to protect passengers, freight and services relies on heavy inborn maintenance. Initiating an accurate model suitable to foresee the change of attitude on components when operating rolling stock systems will assist in reducing lock down and favors heavy productivity. In that light, this paper showcases a suitable methodology to track degradation of components through the blinding of physic laws and artificial intelligent techniques. This model used to foresee failure deterioration rate and remaining useful life (RUL) speculation is case study to showcase its quality and perfection, within which behavioral data are obtained through simulated models initiated in Mathlab. For feature extraction and forecasting issues, different neuro-fuzzy inference systems are designed, learnt and authenticated with powerful outputs gained during this process.

Effect of Texture and Surface Chemistry of Palm Nut Hull Activated Carbon on the Adsorption of Pigments and Free Fatty Acids from Vegetable Oils

Activated carbons were produced from palm nut hull,which is a waste material of palm oil extraction industries.Activated carbons having various pore size distributions and surface composition were obtained by conventional carbonization method via the sulphuric acid solution pre-treatment method.The surface areas,mesopore volume and-OH groups of activated carbons increase with the increases of sulphuric acid solution concentration.The activated carbons obtained were tested for the adsorption of pigments and free fatty acids from palm oil and shea butter.It comes out from this study that the amount of adsorbate(i.e.pigments and free fatty acids)fixed increases with the increase of the adsorption temperature and with the increases of mesopore volume.Intraparticle diffusion,pseudo-first-order and pseudo-second-order kinetics models were used to analyze the kinetics data obtained at different temperatures(temperature range 60℃ to 90℃).Among the kinetics models used,the pseudo-second order was the best applicable model to describe the adsorption of oil pigments and free fatty acid onto activated carbons.The activation energies obtained by applying the Arrhenius equation for the adsorption of pigments were low(i.e.less than 40 kJ·mol^-1 for the both vegetables oils),indicating that the adsorption could be assigned to physisorption.

Antioxidant Activity of the Natural Flavonoid 7-Hydroxy-5,6,4’-trimethoxyflavone Isolated from the Leaves of Lippia rugosa A. Chev

Phytochemical studies and antioxidant activities were carried out on n-hexane, ethyl acetate, ethanol and methanol extracts of the leaves of Lippia rugosa A. Chev (Verbenaceae), a medicinal plant used traditionally in the Cameroonian savannah’s region to protect foodstuffs and to cure degenerative diseases. Results indicated that theses extracts contain terpenoids, phenolic and flavonoid compounds. Except the n-hexane extract, all of the obtained extracts exhibit antioxidant activities with the ethanol extract being the most effective with an inhibition percentage of 85.668% ± 1.233% and an inhibition concentration (IC50) of 58 μg/ml (R2 = 0.987, P < 0.01) at a concentration of 100 mg/ml. Chromatographic separation on silica gel of the ethanol extract led to the isolation of a pure organic compound which was characterized as 7-hydroxy-5,6,4'-trimethox- yflavone by extensive 1D and 2D NMR spectroscopy, a flavonoid exhibiting antioxidative activity with an inhibitory percentage of 25.506% ± 0.205% and inhibition concentration (IC50) of 221 μg/ml (R2 = 0.966, P < 0.01). This is the first time that 7-hydroxy-5,6,4'-trimethoxyflavone is being isolated from L. rugosa and its antioxidant activity evaluated.

In vitro assessment of the effect of microencapsulation techniques on the stability,bioaccessibility and bioavailability of mulberry leaf bioactive compounds

Mulberry(Morus alba L.)leaf extract is well-known for its health-promoting features.However,food processing conditions affect its bioactive profile,which could be limited by encapsulation.Nevertheless,assessing the impact of encapsulating techniques on the digestibility of embedded biocompounds requires further knowledge.Hence,the aimed of this study was to assess the effects of carrier materials and drying techniques on(i)bioaccessibility and bioavailability indexes,(ii)stability of nutraceuticals,and(iii)changes in antioxidant activities of mulberry leaf extract powder by using an in vitro oral-gastrointestinal digestion.Digestion was performed out at 37°C in darkness by shaking encapsulated extract with human saliva during 2 min,followed by 2 h of incubation with a pepsin-HCl mixture,then mixed for 2 h with bile salts and pancreatin.After digestion the samples were acidified and HPLC assayed.A significant(p<0.05)decrease in nutraceuticals content was noted during the intestinal phase with more reduction in gamma-aminobutyric acid(34.91–51.14%)compared to that of flavonols(16.58–28.90%),1-deoxynojirimycin(17.56–20.42%)and phenolic acids(0.53–0.67%)in the gastric digesta.Although encapsulation was observed to enhance the bioaccessibility,negative effects were found in terms of the bioefficiency and bioavailability.Furthermore,encapsulation techniques mostly affected the ion reducing capacity than the radical scavenging capacity.The outcomes suggested that carriers had a major effect on the digestibility and antioxidative activity,whilst the drying techniques mostly affect the bioaccessibility and bioavailability of the flavonols.