Optimization of waste quail eggshells as biocomposites for polyaniline in ammonia gas detection

A simple, cost-effective, and novel chemical sensor for ammonia (NH₃) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet-visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X-ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest NH₃ detection limit of 5.24 ppm with a linear correlation coefficient (R²) of close to unity (0.9932) between the signal and NH₃ gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward NH₃ gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of NH₃ gas detection for at least 4 cycles.     

Characteristics,Stability, and Release of Peanut Sprout Extracts in Powdered Microcapsules by Spray Drying

This study was carried out to investigate the characteristics of powdered microcapsules from peanut sprout extracts prepared by spray drying. The microcapsules were made from medium-chain triglyceride (MCT) as primary coating material and whey protein concentrate (WPC) or maltodextrin (MD) as selected secondary coating materials. The microcapsule studies conducted were microphotograph, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), particle size, moisture contents, sorption, zeta potential, storage stability, and in-vitro study. The surface of microcapsules coated with WPC were rough and smooth, and particle size ranged from 2.86 to 8.59 µm. An FT-IR study revealed that absorption bands at 1,537 and 1,657 cm^?1 of microcapsules can be attributed to the protein amide I and II bands of WPC overlapped by the conjugated C?C. The moisture content was 1.33% in the microcapsules coated with WPC. The moisture sorption increased until 18% at the 90% RH. The yield of peanut sprout extracts from microcapsules was 89.01%. In the in-vitro study, the microcapsules released 2.48 and 6.01% at pH 2.0 and 4.0, respectively, in simulated-gastric fluid, and 61.07 and 89.24% at pH 6.0 and 8.0, respectively, in simulated-intestinal fluid. The preservation rate of the microcapsules dropped down to 60.43% from 89.01% during six months of storage. The stability of peanut sprout extracts in the microcapsules was over 80% at 4 and 20°C during 10-day storage. The zeta-potential of microcapsules was stable with ?30 mV. Based on the data obtained from the present study, the powdered peanut-sprout-extract microcapsules coated with WPC exhibited high stability during storage. Therefore, the powdered microcapsules by spray drying may be useful as a functional ingredient.     

FTIR spectroscopic determination of soap in refined vegetable oils

A new analytical method was developed for the determination of soap in palm and groundnut oils by FTIR spectroscopy. Soap from 0 to 80 mg/kg oil was produced in situ in the oils by adding sodium hydroxide. The FTIR spectroscopy was with a sodium chloride transmission cell, and the partial least-squares statistical method was used to calibrate a model for each oil. The accuracy of the method was comparable to that of AOCS Method Cc17-95, with coefficients of determination (R ²) of 0.98 and 0.98 for both palm and groundnut oils. The standard errors of calibration were 1.84 and 1.36 for the two oils, respectively. The calibration models were cross-validated, and the R ² of cross-validation and standard errors of cross validation were computed. The standard deviation of the difference for repeatability of the FTIR method was better than that for the chemical method used for determining soap in palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy is a possible alternative to the standard wet chemical methods for rapid (2 min) and accurate routine determination of soap in chemically refined vegetable oils.     

Optimisation of enzymatic hydrolysis for concentration of squalene in palm fatty acid distillate

BACKGROUND: Squalene was concentrated from palm fatty acid distillate (PFAD) in this study using commercial immobilised Candida antarctica lipase (Novozyme 435^®). The PFAD was neutralised (NPFAD) using an alkali to liberate the free fatty acids and then hydrolysed at 65 ± 1 °C. The enzymatic hydrolysis on NPFAD was optimised using response surface methodology (RSM) before being neutralised again to obtain a concentrated squalene fraction. RESULTS: A five‐level, three‐factor central composite rotatable design was adopted to evaluate the effects of the enzymatic hydrolysis parameters reaction time (4–12 h), water content (50–70% w/w) and enzyme concentration (1.5–3.5% w/w) on the percentage yield of squalene concentration. The optimal reaction parameters for maximum yield of squalene concentration were identified from the respective contour plots. The optimal enzymatic hydrolysis conditions were a reaction time of 7.05 h, a water content of 61.40% w/w and an enzyme concentration of 2.23% w/w. CONCLUSION: RSM was used to determine the optimal conditions for enzymatic hydrolysis of NPFAD with C. antarctica lipase for maximum recovery of squalene which could be implemented on an industrial scale. Copyright © 2008 Society of Chemical Industry     

The effect of carotene extraction system on crude palm oil quality, carotene composition, and carotene stability during storage

Palm carotene was successfully concentrated from crude palm oil (CPO) by an adsorption process using a synthetic adsorbent followed by solvent extraction. Evaluation of feed CPO and CPO which underwent the carotene extraction process was conducted. The quality of CPO after the extraction process was slightly deteriorated in terms of free fatty acid, moisture content, impurities, peroxide value, anisidine value, discriminant function, and deterioration of bleachability index. However, the CPO still can be refined to produce refined, bleached, deodorized palm oil that meets the Palm Oil Refiners Association of Malaysia specifications. No extra cost was incurred by refining this CPO as the dosage of bleaching earth used was very similar to the refining of standard CPO. The triglyceride carbon number and fatty acid composition of CPO after going through the carotene extraction process were almost the same as CPO data. The major components of the carotene fraction were similar to CPO, which contains mainly α- and β-carotene. The carotene could be stored for at least 3 mon.     

A fourier transform infrared spectroscopic method for determining butylated hydroxytoluene in palm olein and palm oil

A simple, rapid, and direct FTIR spectroscopic method was developed for the determination of BHT content in refined, bleached, and deodorized (RBD) palm olein and RBD palm oil. The method used sodium chloride windows with a 50-mm transmission path. Fifty stripped oil samples of both RBD palm olein and RBD palm oil were spiked with known amounts of BHT concentrations up to 300 mg/kg (ppm). The data were separated into two sets for calibration and validation using partial least squares models. FTIR results for both oils correlated well with results obtained by the IUPAC HPLC-based method. For RBD palm olein, the coefficient of determination (R ²) was 0.9907 and the SE of calibration (SEC) was 8.47 ppm. For RBD palm oil, an R ² of 0.9848 and an SEC of 10.73 ppm were achieved. Because of the significant decrease in analysis time and reduction in solvent usage, this FTIR method for BHT is especially well suited for routine quality control applications in the palm oil industry.     

Lipase‐catalysed production and chemical composition of diacylglycerols from soybean oil deodoriser distillate

Diacylglycerols (DAG) were enzymatically produced by lipase‐catalysed esterification of glycerol with fatty acids from soybean oil deodoriser distillate (SODD). Effects of reaction parameters such as reaction time, temperature, enzyme type, enzyme load, substrate molar ratio and water content, as well as the effect of molecular sieves as water adsorbent were studied. Lipozyme RM IM was determined to be the most effective among the lipases screened. The following conditions yielded 69.9% DAG (all percentages are wt/wt): 4 h reaction time, 65 °C reaction temperature, 10% Lipozyme RM IM, 2.5:1 fatty acid to glycerol molar ratio, and 30% molecular sieves. DAG synthesis of 11.9% was still observed at 10% water content. After purification, the product oil contained 86.3% DAG. This oil consisted predominantly of 1,3‐diolein (19.1%), 1‐oleoyl‐3‐linoleoyl‐glycerol (18.2%) and 1‐oleoyl‐2‐linoleoyl‐glycerol (16.6%). The fatty acid profile of the oil was similar to that of refined, bleached and deodorised (RBD) soybean oil. The % ratio of 1,3‐ to 1,2‐positional isomers of DAG was at 56:44.     

Separation of squalene from palm fatty acid distillate using adsorption chromatography

A method to separate squalene from palm fatty acid distillate (PFAD) using neutralization‐hydrolysis‐neutralization before employing adsorption column chromatography was developed. Extraneous matters, especially free fatty acids (83.8%) and acylglycerols (12.7%), were first neutralized and removed before being subjected to hydrolysis by using commercially available, immobilized Candida antartica lipase, at 65 °C for 8 h. Neutralization followed by hydrolysis and repeated neutralization successfully concentrated squalene from an initial amount of 3.76% to 27.5%. Oil extracted from neutralized‐hydrolyzed‐neutralized PFAD was then passed through a Diaion HP‐20 column using reverse‐phase adsorption chromatography. Squalene was desorbed by hexane, with a recovery of 93%.     

Effect of absorbent in solid‐phase extraction on quantification of phospholipids in palm‐pressed fiber

Palm‐pressed fiber (PPF) is a by‐product of palm oil milling and it has been found to contain a high percentage of phospholipids (PL). The aim of this work was to evaluate the best solid‐phase extraction (SPE) method to purify PL from PPF. The purified PL were analyzed using high‐performance liquid chromatography (HPLC) with an evaporative light‐scattering detector (ELSD). The oil was extracted from PPF using the Folch method and classes of PL were purified using SPE. Different solvent phases and normal‐phase SPE cartridges [silica (Si), aminopropyl‐bonded silica (NH₂) and diol‐bonded silica (2OH)] at the same ratio of oil to sorbent mass were used to study the separation of PL from the extracted oil. The recovery of each standard PL was performed in a model oil system with the same amount of standard PL being added, and the repeatability of the SPE method was investigated. The isolation of PL by SPE diol cartridge and subsequent analysis by HPLC/ELSD have shown to be an accurate and reproducible analytical method for the determination of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and lysophosphatidylcholine in PPF. This method provided a high yield and rapid separation of PL in PPF with less contamination from other lipid groups.