Extra virgin olive oil (EVOO) is categorized as expensive oil due to high-quality nutritional value. Unfortunately, EVOO is easily adulterated with other low-quality edible oils. Therefore, this study was done to differentiate and analyze the adulteration of EVOO with other edible oils using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The study was used several edible oils included canola oil, corn oil, sunflower oil, and soybean oil as an adulterant for EVOO. The adulterant EVOO samples were prepared by mixing with dissimilar concentrations of the solely edible oils (20 %, 40 %, 60 % and 80 % (v/v)). The main functional groups of EVOO and other edible oils are O-H, C-H, C=C and C=O groups were assigned around 3500 cm-1, 2925 cm-1, 3006 cm-1 and 1745 cm-1 wavenumbers, respectively. From the comparison of EVOO and other adulterant edibles oil spectra, it showed that the EVOO has the lowest absorbance intensity at around 3006 cm-1 represented double bond which is closely related to the composition of oil sample. The adulteration of EVOO was evaluated by analysing the changes in the absorbance based on the linear regression analysis graph of the bands at 3006 and 2925 cm-1 and the limit of detection (LOD) was measured. The graph of A3008/A2925 with good relative coefficients (R2) and lower LOD is more favourable than the linear regression graph of A3006 versus percentage of edible oils added in EVOO. This study showed that ATR-FTIR spectroscopy is a convenient tool for analysing the adulteration of EVOO.
The cloud point extraction (CPE) method was developed to determine the zinc prior to Ultraviolet-visible (UV-Vis) spectrophotometry detection. Triton X-100was applied as extractant based on the complexation reaction of Zn(II) ions with ethylenediaminetetraacetic acid (EDTA). Under optimal conditions, the CPE was used to determine the concentration of zinc in canned food samples. The amounts of zinc found in the food samples were in the range of 0.005-0.007 mg/L with RSD of < 8 %. This confirmed that the proposed CPE method is suitable for the determination of zinc in food samples, indicating the concentration of zinc was within the permissible limit.
A simple and low
cost cloud point extraction (CPE) method was developed for the determination of
tartrazine in food samples by spectrophotometry detection at a wavelength 427.5 nm. The CPE was
performed by utilizing Tween 20 and sodium carbonate (Na 2 CO 3 ) as extractant and separation
accelerator, respectively. Fac tors that influenced CPE such as surfactant and salt concentrations, pH
and temperature were optimized in the context of extracting tartrazine from aqueous media. Under an
optimal condition, the proposed CPE was applied for the determination of tartrazine in sweets and
concentrated syrup juice, which represented food samples. A CPE UV Vis method showed linear
calibration within the range of 1 12 mg L 1 of tartrazine with a regression coefficient was 0.9957 . The limit of detection (LOD) and limit of quantifi cation (LOQ) of the method were 0.88 mg L 1 and 2.96
mg L 1 , respectively. The relative standard deviation (RSD) was found to be < 3.00 %. The amount of tartrazine found in food samples was 1.22 6.12 mg L 1 . The results showed that the proposed CPE
method was applicable for the determination of tartrazine in food samples and the tartrazine content in the food samples was permitted according to the guidelines from the European Food Safety Authority (EFSA)