Rapid determination of the storage time of cold-pressed berry seed oils using flash gas chromatography E-Nose coupled with chemometrics

Abstract

Since oils containing a high content of polyunsaturated fatty acids are susceptible to oxidation, it is necessary to monitor the degree of deterioration during storage, e.g. by measuring the volatile compounds. This study aimed to assess volatile profiles of berry seed oils in terms of the authenticity and the deterioration assessment using flash gas chromatography (FGC E-Nose) combined with chemometrics. Berry seed oils (raspberry, blackcurrant, strawberry, chokeberry), obtained from three different suppliers and stored for a one year in brown bottles at room temperature, were analysed after 0, 3, 6, 9 and 12 months of storage. Principal component analysis enabled separation of oil samples by different berry types, suppliers and storage times. To predict the storage time, partial least square (PLS) models were built for each type of berry oil. Determination coefficients (R2) in cross-validation ranged from 0.842 (RMSECV = 1.69 months) to 0.969 (RMSECV = 0.75 months). Selecting the specific regions of chromatograms improved the residual prediction deviation (RPD) to values between 2.8 and 5.7, which indicated the suitability of the PLS models to predict the storage time in the quality control of berry oils.