Screening Lactic Acid Bacteria for Antimicrobial Compound Production

Lactic Acid Bacteria was known as potential probiotic used in food industries and dairy products and probable to produce antimicrobial compound that inhibit variety of microorganisms. The objectives of the research are to determine the optimum condition and glucose utilization in relation to antimicrobial compound production. Two species of Lactic Acid Bacteria namely Lactococcus and Lactobacillus were used as probiotic. The Lactic Acid Bacteria were fermentated in different medium, initial substrate pH and incubation temperature for the production of antimicrobial compound. The test organisms such as E.coli and Salmonella were selected as test organisms. Amongst the two species of Lactic Acid Bacteria, Lactococcus produced the highest amount of antimicrobial compound than Lactobacillus

Bio-polymer chitosan and corn starch with extract of hibiscus rosa-sinensis (hibiscus) as PH indicator for visually-smart food packaging

This study is focusing on the presence of pigments called anthocyanin in hibiscus, can be used as pH indicator as the pigments react with OH- ions before changing its color depending on the acidity or alkalinity of the surroundings. Hence, a system for pH monitoring based on chitosan, corn starch and phytochemical extract from Hibiscus rosa-sinensis (hibiscus), all inexpensively obtained from renewable sources is developed. Chitosan, corn starch and hibiscus extract were used to produce biopolymer pH indicator for smart food packaging. The system is then characterized by using FTIR, as well as light microscopy. In order to validate the use of this system as a meat spoilage detection sensor, application tests were conducted with chicken breasts. The results show that the system has good optical and morphological properties and is very sensitive to pH variations. During the application test, the system visually indicated pH changes. This shows a clear response to pH variation of the samples. Therefore, it has potential to be used as a visual indicator of the storage and consumption conditions of food

Establishment of physicochemical measurements of water polluting substances via flow perturbation gas chromatography

Spillage of water polluting substances via industrial disaster may cause pollution to our environment. Thus, reversed-flow gas chromatography (RF-GC) technique, which applies flow perturbation gas chromatography, was used to investigate the evaporation and estimate the diffusion coefficients of liquid pollutants. Selected alcohols (99.9% purity) and its mixtures were used as samples. The evaporating liquids (stationary phase) were carried out by carrier gas-nitrogen, 99.9% purity (mobile phase) to the detector. The findings of this work showed the physicochemical measurements may vary depending on the composition of water and alcohol mixtures, temperature of the mixtures, as well as the types of alcohol used. This study implies that there is a variation in the results based on the concentration, types and temperature of the liquids that may contribute in the references for future research in the area of environmental pollution analysis

Study the Effect of Imposing Surfactants toward the Evaporation of Low Molecular Weight Alcohol

In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the evaporation of low molecular weight alcohol. Evaporation rates as well as the diffusion rates of methanol are determined with a surfactant monolayer on the surface of the liquid; while nitrogen acts as carrier gas, at 313 K. The precision (>99.9) and accuracy of this investigation demonstrates the potential of current methodologies for environmental impact studies; this is further verified when the results are compared with the available literature. The varying evaporation rates of methanol in the presence of varying amounts of Triton X-100 reflects that application of surfactants do damper the evaporation rates of liquid pollutants; without interference with the former’s diffusion coefficients. High amounts of Triton X-100 are required for retardation of evaporation rates, suggesting the formation of a densely packed surface monolayer or the formation of an insoluble monolayer

FTIR and TGA analysis of biodegradable poly(lactic acid)/ treated kenaf bast fibre: effect of plasticizers

A biodegradable composite (PLA/KBF blends) was prepared using melt blending technique in a brabender mixer and characterized with FTIR and TGA analyzer. Five percent of triacetin and glycerol contents were used as plasticizers to plasticise PLA matrix. KBF was treated with 4% NaOH solution, while 30 wt% of fibre loading was used constantly for all the composite samples. From the FTIR analysis, the additions of triacetin and glycerol to PLA composites did not produce any significant difference, and there were no chemical changes in both the plasticized PLA with the treated and untreated KBF, respectively. Observation done on the TGA analysis revealed that both plasticizers did improve the thermal stability of the composites, and this might be due to the modification on the fibre surfaces, which further led to the delay in the degradation of the PLA matrix and to significant stabilization effect

Determination of some properties of used cooking oil using AAS, bomb calorimeter and GC-MS techniques

Most of the used cooking oil from households and catering premises in Malaysia will eventually ends up in wastewaters. It will be discharged to the surface of waters because no alternative steps were taken to overcome the waste from used cooking oil. As a component of wastewater, oil is classified together with fats and waxes as grease. This trend results in the generation of a vast waste stream that needs to be properly managed to avoid environmental damage. Thus, the information regarding on the waste cooking oil properties is needed to contribute knowledge for future research where the waste may reformed to value added product. Preliminary analysis of used cooking oil properties via GCMS using capillary column shows n-Hexadecanoic acid and Oleic acid as the major compounds present in the used frying oil. The analysis for determination of volatile and moisture content with 3 replicates show an average of 0.02% moisture and volatile content, which the experimental procedure was based on MPOB Test Methods

The role of tin and magnesium in assisting liquid phase sintering of aluminum (Al)

This study aims to investigate the effect of tin (Sn) and magnesium (Mg) on the sintering response of sintered Al. Although this topic has been extensively reported, details on the combined effect of Sn and Mg that function as sintering additives are still limited. The current study discusses the effect of the combined use of Sn and Mg to assist aluminium (Al) in liquid phase sintering via the powder metallurgy technique. The results demonstrated that the densities of sintered Al increased from 2.5397 to 2.575 g/cm3 as the Sn content increased from 1.5 to 2.5 wt. % respectively. Accordingly, the physical characteristics of sintered Al were transformed from black to silver, which confirmed the reduction in the oxygen content (oxide layer reduction) from 0.58 to 0.44 wt. % respectively. Additionally, the microstructure of the resultant sintered Al demonstrated that effective wetting by Sn addition was obtained at its maximum content of 2.5 wt. % with a greater micro pores reduction and better metallurgical bonding between Al particles. Therefore, the introduction of different Sn content, along with Mg element, was found to further improve the sintering response of the resultant sintered Al that consequently improved its densities and physical characteristics

Preliminary development of porous aluminum via powder metallurgy technique

Porous aluminum has been extensively studied, particularly in the field in which lightweight and high stiffness properties are essential. In this study, a preliminary investigation is performed to determine the optimum sintering temperature to develop porous aluminium by a powder metallurgy technique, using polymethylmethacrylate as a space holder. The effects of the sintering temperatures on the physical characteristics, oxidation level, microstructure and sintered density of the porous specimen are systematically evaluated. Based on the results, an increase in the sintering temperature from 580 °C to 600 °C changes the colour of the porous aluminum body from a silver‐like colour to a gold‐like colour, with some of the specimens encountering severe cracking, spalling and even collapsing. As such, the oxygen content is significantly increased from 0.45 wt.% to 2.14 wt. %, suggesting the oxidation phenomenon. In line with this, an obvious appearance of particle boundaries with less macro‐pores formation is also observed. Additionally, the sintered density of the porous specimen is found to reduce from 1.305 g/cm3 to 0.908 g/cm3. Therefore, fabrication of the resultant porous aluminium at 580 °C is an ideal condition in this study, owing to the ideal combination of physical characteristics, microstructure, oxidation level and sintered densit

Mechanical properties of gracilaria lichenoides reinforced bioplastic film

In this study, the mechanical properties of gracilaria lichenoides with additional of plasticizer and filler were evaluated. For samples with the addition of 5.5% of plasticizer, produced low tensile strength and this results is vice versa with elongation at break results. The tensile strength of the bioplastic continuously decreases from 14.8 to 2.7MPa as the plasticizer increases up from 1.5% to 5.5%. This phenomenon was analyses under scanning electron microscope (SEM), it shows that, the formation of pores and crystal agglomeration at sample with 5.5% glycerin. To alter these flaws, squid bone is introduce as filler to the bioplastic. Based on the analysis, additional of 6% filler content did alter the tensile strength up to 8 MPa with 3% of the elongation at break

Effects of phenolate ions on cationic micellar growth / Khalisanni Khalid

In this study, the effects of phenolate and its substituted ions on cationic micellar growth involving different alkyl substituted phenolate salts, MX and CTABr micelles in aqueous system were determined with the interest of investigating the relationship of ion-exchange constant to the micellar aggregation behavior by using rheological technique and microscopy analysis. By the use of psedophase micellar model, the value of micellar binding constant, (KS) of PSa- or PS- was determined in the absence and presence of inert salt. The non-linear least squares calculated value of KS0 (KS in the absence of inert salt) was found to be 6748 ± 435 M-1. This is the first study which describes the use of PSa- as a probe molecule to determine the values of RXBr or KXBr by using a semi-emperical spectrophotometric (SESp) method. The use of RXBr refers to the relative binding constant value where the KBr value of spherical micelles is used as a reference (denominator value is the binding constant of spherical micelles) and KXBr is refers to ion exchange constant value of nanoparticle aggregates (spherical/ wormlike/ vesicle). Since bromide ion has been considered as a reference counterion to determine binding constant of other counterions, the catalytic effects of CTABr/NaX/H2O (X=Br, Cl) nanoparticle catalysts on rate constant were investigated at [PS-] = 0.2 mM, [NaOH] = 30 mM, [Pip] = 100 mM at different [CTABr]. The results revealed that the values of kobs at [NaX]=0 and 6 mM ≤ [CTABr]T ≤ 10 mM were ten times smaller than the value of kobs at [CTABr]T=[NaX]=0 (X=Br, Cl). The investigation of the effects of substituted phenolate ions on cationic micellar growth were carried out for sodium phenolate (C6H5ONa), 2-ethyl sodium phenolate (2-ethyl C6H4ONa), 3-ethyl sodium phenolate (3-ethyl C6H4ONa), 4-ethyl sodium phenolate (4-ethyl C6H4ONa), 2-propyl sodium phenolate (2-propyl C6H4ONa), 4-propyl sodium phenolate (4-propyl C6H4ONa), 3-isopropyl sodium phenolate (3-isopropyl C6H4ONa) and 4-isopropyl sodium phenolate (4-isopropyl C6H4ONa) at [PS-] = 0.2 mM, [NaOH] = 30 mM, [Pip] = 100 mM, [CTABr] = 6, 10 and 15 mM respectively at 35°C. The RXBr values of counterions were 6.3, 24.0, 24.4, 32.3, 66.3, 145.9, 60.8 and 66.6 for phenolate ions (C6H5O-), 2-ethyl phenolate ions (2-etyl C6H4O-), 3-ethyl phenolate ions (3-ethyl C6H4O-), 4-ethyl phenolate ions (4-ethyl C6H4O-), 2-propyl phenolate ions (2-propyl C6H4O-), 4-propyl phenolate ions (4-propyl C6H4O-), 3-isopropyl phenolate ions (3-isopropyl C6H4O-) and 4-isopropyl phenolate ions (4-isopropyl C6H4O-) respectively. By means of the correlation between RXBr values and rheological analysis with the evident of microscopic studies at [CTABr] = 15 mM, the microstructures of micellar self assembly of flexible nanoparticles were found as follows for C6H5O- = spherical, 2-ethyl C6H4O- = spherical, 3-ethyl C6H4O- = spherical, 4-ethyl C6H4O- = wormlike, 2-propyl C6H4O- = vesicle, 4-propyl C6H4O- = rodlike, 3-isopropyl C6H4O- = vesicle and 4-isopropyl C6H4O- = wormlike. The findings revealed the increase of RXBr values lead to the changes of spherical micelles to wormlike, rodlike or vesicles micelles