Search

Palm olein has been commercially used as frying medium in batch deep-fat frying. During frying, the oil usually deteriorates due to the exposure to high temperature. In this study, a fluorescence spectroscopy technique was applied to monitor the deterioration of refined, bleached, and deodorized palm olein (RBDPO) in batch deep-fat frying. 22.5 kg of French fries were used as the frying material. In 30 batches, the french fries were intermittently fried at 185 ± 5°C for eight hours a day over five consecutive days capturing 40 hours. The fluorescence intensity of the RBDPO was recorded with excitation at 390 nm and resulting emission of 465 nm. The fluorescence intensity of the RBDPO over five days of frying decreased considering the wavelength range of emission 430-640 nm and excitation 360-430 nm. The decreased in intensity of fluorescence emission and excitation spectra were inversely correlated with the FFA content of the oil samples. This study demonstrates the potential of fluorescence spectroscopy in monitoring the deterioration of RBDPO during batch deep-fat frying. [ABSTRACT FROM AUTHOR]

Degradation and deterioration of crude palm oil (CPO) is a major concern in the palm oil industry because it could affect the quality of palm oil products. The development of rapid and non-destructive measuring techniques is needed to enhance the efficiency of palm oil quality monitoring. This study used dielectric spectroscopy to detect possible sludge contamination in CPO. Dielectric properties of CPO were measured at different temperatures and sludge contamination levels using a liquid dielectric test fixture that was connected to an impedance analyzer with frequencies ranging from 3 to 30 MHz. The variations in dielectric properties were analyzed using ANOVA and Duncan's multiple range test. Principal component regression (PCR) and partial least squares (PLS) analysis were used for model development to predict sludge contamination. The results showed that there was a significant difference in dielectric constant as the temperature increased from 28°C to 55°C (p < 0.0001). The dielectric constant also increased from 3.01 to 63.53 with increasing contamination levels. Generally, there were significant differences between the dielectric constants of pure and contaminated CPO (p < 0.0001). The PCR and PLS calibration models showed good prediction ability of sludge contamination at different temperature levels. The classification of sludge contamination yielded very strong correlation, with r² values ranging from 0.91 to 0.98. The best result was obtained at 28°C with the lowest value of standard error cross-validation (SECV) of 1.04%. The results showed that dielectric spectroscopy has strong potential for CPO quality monitoring. [ABSTRACT FROM AUTHOR]

The response surface method was applied in this study to improve cellulase production from oil palm empty fruit bunch (OPEFB) by Botryosphaeria rhodina. An experimental design based on a two-level factorial was employed to screen the significant environmental factors for cellulase production. The locally isolated fungus Botryosphaeria rhodina was cultivated on OPEFB under solid-state fermentation (SSF). From the analysis of variance (ANOVA), the initial moisture content, amount of substrate, and initial pH of nutrient supplied in the SSF system significantly influenced cellulase production. Then the optimization of the variables was done using the response surface method according to central composite design (CCD). Botryosphaeria rhodina exhibited its best performance with a high predicted value of FPase enzyme production (17.95 U/g) when the initial moisture content was at 24.32%, initial pH of nutrient was 5.96, and 3.98 g of substrate was present. The statistical optimization from actual experiment resulted in a significant increment of FPase production from 3.26 to 17.91 U/g (5.49-fold). High cellulase production at low moisture content is a very rare condition for fungi cultured in solid-state fermentation. [ABSTRACT FROM PUBLISHER]

This study was conducted to evaluate antimicrobial properties of ethanolic extracts of the leaves of Nephelium lappaceum, Curcuma longa, Cinnamomun cassia, Durio zibethinus, Vitex trifolia, Amaranthus tricolor, Syzygium samarangense and Manihot esculenta. Antibacterial properties of the extracts were studied against fifteen strains of different gram positive and gram negative pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Vibrio para, and Escherichia coli using the agar disk diffusion method. Among the tested extracts, only Amaranthus tricolor exhibited specific inhibition of one of the tested bacteria; Bacillus cereus. Using the microdilution method, its minimum inhibitory concentration (MIC) value was determined to be 20 mg/mL. [ABSTRACT FROM AUTHOR]