Iodine Value and Fatty Acids Determination on Pig Fat Samples by FT-NIR Spectroscopy: Benefits of Variable Selection in the Perspective of Industrial Applications

Abstract

In this work, FT-NIR spectroscopy was employed to determine iodine value (IV) and fatty acids (FA) content of pig fat samples, through the combined use of signal preprocessing, multivariate calibration, and variable selection methods. In particular, the main focus was on the use of variable selection methods, both in order to improve the predictive performance of the calibration models, and to identify relevant wavelengths that could be subsequently used for the development of simple, fast, and cheap hand-held devices, able to measure IV and FA content directly on the fat without the need of any sample pretreatment. Firstly, for each property of interest, partial least squares (PLS) multivariate calibration models were calculated considering the whole spectral range and testing different signal preprocessing methods. Then, once chosen the optimal signal preprocessing method, a two-step variable selection procedure was applied. In the first step, the interval-PLS variable selection algorithm was used to calculate a set of calibration models, whose outcomes were considered altogether in the second step, in order to select the optimal calibration model. The variable selection procedure allowed to lower the number of spectral variables retained by the model, and often led to an increase of the performance in prediction of the external test set samples

Investigations on a novel collector for anionic reverse flotation separation of quartz from iron ores

“…4 (a) and (b), respectively. Iodine value (IV) is an index of the degree of unsaturation of a fatty tissue: the more the tissue is rich in saturated fatty acids, the lower is the IV value, and vice versa (Foca et al, 2016). The number of double bonds of fatty acid are crucial for the determination of IV (Kyriakidis and Katsiloulis, 2000).…”

European Local Pig Breeds - Diversity and Performance. A study of project TREASURE

“…For what regards fatty acid composition, the interpretation of the collected information is again difficult due to the important differences among studies with respect to diet and feeding, final body weight and age, and fatness, all these factors affecting fatty acid composition of tissues. Although it is difficult to make comparisons due to the differences in rearing and management conditions, the collected data indicate that local pig breeds in general exhibit higher proportion of monounsaturated fatty acids (MUFA) and lower proportion of polyunsaturated fatty acids (PUFA) as compared to the fatty acid profiles generally reported in conventional pig breeds [27][28][29]. The proportion of MUFA is mainly above 50% and PUFA below 12-13% in fatty acid profiles of intramuscular and back fat for the breeds considered, although in that respect, some of the breeds are closer to the conventional ones ( Figure 6).…”

Non-Destructive Spectroscopic Techniques and Multivariate Analysis for Assessment of Fat Quality in Pork and Pork Products: A Review

“…On intact subcutaneous fat, interval PLSR (iPLSR) was used by Sørensen, et al [ 59 ] to calibrate a NIRS for IV prediction in unmelted fat obtaining high values of coefficient of determination. Foca, et al [ 60 ] also considered the importance of variable selection in the perspective of developing robust models necessary for predicting the IV and FAs of intact pork fat. By the combination of signal processing and iPLSR, a two-step variable selection was applied to select the most informative variables that provide the most correlation with the NIR spectral data.…”