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.
Soluble solid content (SSC) is one of the important traits that indicate the ripeness of banana fruits.
Determination of SSC for banana often requires destructive laboratory analysis on the fruit. An impedance measurement technique was investigated as a non-destructive approach for SSC determination of bananas. A pair of electrocardiogram (ECG) electrode connected to an impedance analyser board was used to measure the impedance value of bananas over the frequency of 19.5 to 20.5 KHz. The SSC measurement was conducted using a pocket refractometer and data was analysed to correlate SSC with impedance values. It was found that the mean of impedance, Z decreased from 10.01 to 99.93 KΩ at the frequency of 20 KHz, while the mean value of SSC increased from 0.58 to 4.93 % Brix from day 1 to day 8. The best correlation between impedance and SSC was found at 20 KHz, with the coefficient of determination, R2 of 0.87. This result indicates the potential of impedance measurement in predicting SSC of banana fruits.