FTIR spectroscopy in combination with multivariate calibration of Partial Least Square (PLS) has been developed for quantification of curcumin in the ethanolic extracts of Curcuma longa Linn and Curcuma xanthorriza Roxb. The optimization was done by selecting the best wavenumbers regions capable of providing the high coefficient of determination (R 2) and low values of Root Mean Square Error of Calibration (RMSEC). Finally, wavenumbers region of 2000-950 cmG 1 was selected for prediction of curcumin in the extracts. The correlation between actual values of curcumin determined by HPLC and FTIR predicted values using FTIR spectroscopy combined with PLS in ethanolic extract of C. longa and C. xanthorriza at 2000-950 cmG 1 revealed R 2 values of 0.96 and 0.99, respectively. The RMSEC values obtained are 0.299 and 0.089 for C. longa and C. xanthorriza, respectively. The high value of R 2 and low value of RMSEC indicated the high accuracy and precision of FTIR spectroscopy for quantification of curcumin in the extracts. These results indicated that FTIR spectroscopy combined with PLS is an alternative technique for determination of curcumin in Curcuma species. The developed method (FTIR spectroscopy) is rapid, no sample preparation and not involving excessive solvents and reagents.
The identifications of species in meat products have created interests since these foods became the target of forgery and fraud in the market. The presence of pork in food products is not allowed for the Muslim community. Hence, an analysis is necessary to detect the presence of pork in processed meat products, such as in dendeng (dried meat) product. Real time polymerase chain reaction using mitochondrial displacement loop686 and cytochrome b (cytb) gene primers was used to identify specific pork DNA among other four types of DNA species; namely beef, chicken, goat, and horse. This method was also used to identify pork DNA in the laboratory processed pork-beef dendeng as well as commercial dendeng from market. The results showed that real time polymerase chain reaction using displacement loop686 and cytb gene primers were able specifically to distinguish between pork DNA and the other species. The lowest concentration of 0.5% of pork DNA in a mixture of pork-beef processed products of dendeng was able to be detected by both primers with the product amplification of 114 and 134 bp (base pair) for the displacement loop686 and 149 bp for cytb gene, respectively. High sensitivity was also obtained when both primers were applied with the lowest detection limit of 5 pg/µL pork DNA. The results of the six commercial dendeng amplification using both primers showed no amplified products present, meaning that these products do not contain porcine DNA.
The substitution of rat meat (non-halal meat) in beef-based sausage products is illegal practice. This study was aimed to develop Fourier transform infrared (FTIR) spectroscopy in combination with chemometrics for analysis of rat meat in sausage employing three different lipid extraction techniques. Lipid was extracted from the sausages using Bligh and Dyer, Folch, and Soxhlet methods. The lipid extracted was then analyzed using FTIR spectroscopy combined with chemometrics of principal component analysis (PCA) and partial least square (PLS) calibration. The absorbance values at wavenumbers region of 750-1800 cm −1 were selected in PCA for classification and PLS modeling for quantification. PCA was successfully used to classify rat meat and beef lipids extracted by the three lipid extraction methods. The coefficient of determination (R 2 ) and root mean square error of calibration (RMSEC) during PLS calibration modeling on lipid extracted from beef-rat meat sausages using Bligh and Dyer, Folch, and Soxhlet method were 0.945 and 2.73%; 0.991 and 1.73%; 0.992 and 1.69%, respectively. The validation study showed that R 2 and root mean square error of prediction values for the correlation between actual value of rat meat and FTIR predicted value using lipids extracted by Folch and Soxhlet method were 0.458 and 18.90%, and 0.983 and 4.21%, respectively. Statistical analysis using independent t-test (p = 0.95) showed that there were significant differences on the content of some fatty acids of beef lipid and rat lipid as determined using gas chromatography. The contents of fatty acids of C12:0, C16:0, C16:1 cis 9, and C18:0 in rat lipid were higher than those in beef lipid, and the otherwise was observed for fatty acids of C14:1 cis 9, C15:0, C17:0, C17:1 cis 10, unsaturated C18, and C21:0. The difference in lipid composition, as indicated in FTIR spectra profiles and fatty acid composition, can be used as fingerprint technique for analysis of rat meat in beef sausage for halal authentication purpose.
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