DSC Melting Profile of Cold-Pressed Hemp Seed Oil as an Authenticity Fingerprint Influenced by Scanning Rate

Featured Application Current study evaluated the possibility of using melting profiles obtained by differential scanning calorimetry (DSC) for cold-pressed hemp seed oil authentication. It was shown that during phase transition, the heating rate had a significant influence on the thermal behavior of the oil, as manifested by a different shape of the melting profile. Only in the case of a higher scanning rate of 5 degrees C/min was the similarity of curve shapes for all Henola cultivar oils observed, which can be utilized in analytics for profiling. Multivariate data analysis, such as PCA and LDA, showed that DSC parameters enabled distinction of the oils in terms of the seed quality used for pressing (fresh vs. stored). Among the variety of edible cold-pressed oils on the market, hemp seed oil is becoming increasingly popular among scientists and consumers due to its plethora of nutritional compounds. In this study, the goal was to examine the thermal characteristics of cold-pressed hemp seed oil pressed from seeds of the Henola cultivar procured by five different suppliers in two different seasons. This aim of this research was to establish how various scanning rates can affect the unique thermal profile of cold-pressed hemp seed oil in terms of an authenticity assessment. The melting transition was manifested by curves with four peaks for all hemp seed oils; however, they differed for each scanning rate in terms of the shape and peak intensity. Comparing the curves obtained at heating rates of 1 and 2 degrees C/min, noticeable differences were observed in the melting transition parameters between hemp seed oils, showing that small differences in fatty acid composition can cause changes in DSC profiles. In contrast, at a scanning rate 5 degrees C/min, the melting curves were similar for all hemp seed oils. It was also observed that for all the scanning rates, there was a strong negative correlation between the total content of polyunsaturated fatty acids (Sigma PUFAs) and the peak temperature of the three peaks (T(m)2, T(m)3, and T(m)4). The most abundant fatty acids were PUFAs, i.e., linoleic acid (C18:2), with contents ranging from 47 to 55%; and alpha-linolenic acid (C 18:3 n-3), with contents ranging from 17 to 25%. The application of linear discriminant analysis (LDA) enabled a discriminant model to be built based on the DSC data obtained for differentiation of oils pressed from fresh and stored seeds.

Automated summary

This study examined the possibility of using DSC melting profiles to authenticate cold-pressed hemp seed oil. The results showed that the heating rate had a significant influence on the thermal behavior of the oil, allowing for differentiation of different types of hemp seed oil. Multivariate data analysis demonstrated that DSC parameters could distinguish oils pressed from different qualities of seeds. The aim of the research was to assess the authenticity of cold-pressed hemp seed oil through its thermal characteristics at various scanning rates.