Assessment of thermal properties of hull-less pumpkin seeds using differential scanning calorimetry

Today, people are focusing on maintaining a healthy lifestyle and controlling what they eat. By choosing healthy snacks, we are able to avoid the negative consequences of regularly eating unhealthy food. For this reason, one of the most valued products may be the oil-rich hull-less pumpkin. Seeds are a great alternative to the snacks available on the market, but they can also be used to enrich dishes with characteristic features. These seeds can be eaten raw, dried, roasted or as an oil extracted from the seeds. The aim of this research was the analysis of hull-less pumpkin seeds, including the determination of theirmelting parameters using DSC thermal heating curves, and the crystallization parameters, using DSC cooling curves. Ten genetic varieties of hull-less pumpkin seeds were used to conduct the DSC heating and cooling analysis. Two peaks present on the DSC heating curves of seeds providedevidence of low-melting triacyclglycerols with polyunsaturated fatty acids (first peak), and a medium-melting fraction rich in triacyclglycerols with monounsaturated and saturated fatty acids (second peak). The third peak present on the heating DSC curves of pumpkin seeds was related to the decomposition of low-molecular weight saccharides and poly- and oligosaccharides. On crystallization curves, two exothermic peaks were observed. Two peaks indicated the crystallization temperature of the oil contained in the hull-less pumpkin seeds. A negative temperature of the peak on the heating curves indicated the presence of valuable unsaturated fatty acids. A lower peak temperature was evidence of the presence of fatty acids, with a greater number of unsaturated bonds. A similar pattern was observed for the cooling curves in relation to the fat crystallization process. An analysis of DSC heating and cooling curves showed the similarity of the thermal profiles of all of the samples with respect to each other, which suggestes a correlation between their thermal properties and chemical composition.