Abstract

Background:
The Muslim population is very concerned about halal food. Nowadays, there is a growing awareness among consumers regarding the adulteration of food. High-quality Gabus fish oil (halal) is very susceptible to being adulterated with Pork oil (non-halal) by unethical producers to gain greater profits.

Aim:
The research objective was to employ FTIR-ATR Spectroscopy and GC-MS in combination with chemometrics for the analysis of pork oil adulteration in Gabus fish oil.

Methods:
Extraction of Gabus fish oil using the pressing method and pork oil using the soxhlet method. The oil components extracted were then analysed using FTIR-ATR Spectroscopy combined with chemometrics of LDA (Linear Discriminant Analysis) and multivariate calibrations of PLS (Partial Least Square) and PCR (Principle Component Regression) using optimised conditions. The GC-MS data from methyl esther were processed using chemometrics Principal Component Analysis (PCA) to group Gabus fish oil, pork oil and palm oil.

Results:
The absorbance values at wavenumbers regions of 1500-1000 cm-1 were selected for discrimination between Gabus fish oil and Gabus fish oil adulterated with pork oil using chemometrics of LDA. LDA applied to the same wavenumbers region utilized in the quantitative analysis successfully classified Gabus fish oil, pork oil, and a Gabus-pork oil mixture with an accuracy of 100%. The prediction of pork oil was successfully determined using multivariate calibrations of PLS and PCR using optimised conditions. There are three fatty acid markers found in Gabus fish oil caprylate acid, pentadecanoic acid and arachidate acid. PCA was applied for data GC-MS interpretation. Analysis by PCA was able to cluster and discriminate Gabus fish oil, pork oil and palm oil.

Conclusion:
FTIR-ATR spectroscopy and GC-MS coupled with chemometrics is a rapid and accurate method for detecting and quantifying pork oil in Gabus fish oil for halal authentication.

Key words: Halal authentication, Gabus fish oil, FTIR spectroscopy, GC-MS, Chemometrics