Authentication ofNigella sativaSeed Oil in Binary and Ternary Mixtures with Corn Oil and Soybean Oil Using FTIR Spectroscopy Coupled with Partial Least Square

Abdul Rohman,Rizka Ariani

doi:10.1155/2013/740142

Abstract

Fourier transform infrared spectroscopy (FTIR) combined with multivariate calibration of partial least square (PLS) was developed and optimized for the analysis of Nigella seed oil (NSO) in binary and ternary mixtures with corn oil (CO) and soybean oil (SO). Based on PLS modeling performed, quantitative analysis of NSO in binary mixtures with CO carried out using the second derivative FTIR spectra at combined frequencies of 2977–3028, 1666–1739, and 740–1446 cm−1 revealed the highest value of coefficient of determination (R 2, 0.9984) and the lowest value of root mean square error of calibration (RMSEC, 1.34% v/v). NSO in binary mixtures with SO is successfully determined at the combined frequencies of 2985–3024 and 752–1755 cm−1 using the first derivative FTIR spectra with R 2 and RMSEC values of 0.9970 and 0.47% v/v, respectively. Meanwhile, the second derivative FTIR spectra at the combined frequencies of 2977–3028 cm−1, 1666–1739 cm−1, and 740–1446 cm−1 were selected for quantitative analysis of NSO in ternary mixture with CO and SO with R 2 and RMSEC values of 0.9993 and 0.86% v/v, respectively. The results showed that FTIR spectrophotometry is an accurate technique for the quantitative analysis of NSO in binary and ternary mixtures with CO and SO.

Highlights

Nigella sativa L. known as black cumin has been used for centuries, especially in the Middle East and Southeast Asia
Fourier transform infrared spectroscopy (FTIR) spectroscopy in combination with multivariate calibration has been used for authentication of extra virgin olive oil from palm oil [19], authentication of olive oil from some vegetable oils [20, 21], and classification and quantification of corn oil and sunflower oil in olive oil [22], as well as for authentication of Nigella sativa oil from grape seed oil [12]
The standard of fatty acid methyl esters (FAMEs) of 37 compounds was bought from Sigma Chemicals

Summary

Introduction

Nigella sativa L. known as black cumin has been used for centuries, especially in the Middle East and Southeast Asia. The mixing of incompatible materials can be associated with restrictions by certain religion, like adulteration oils with lard Several methods such as high performance liquid chromatography (HPLC) [14], carbon isotope ratio [15], and electronic nose [16] have been developed to detect the adulteration of edible oils. FTIR spectroscopy in combination with multivariate calibration has been used for authentication of extra virgin olive oil from palm oil [19], authentication of olive oil from some vegetable oils [20, 21], and classification and quantification of corn oil and sunflower oil in olive oil [22], as well as for authentication of Nigella sativa oil from grape seed oil [12].

Materials and Methods

Result and Discussion

Findings

Conclusion