Effect of Different Processing Methods on the Quality of Tomato Seed Oil

This study aimed to investigate the effects of four different preparation processes, namely, cold pressing, hot pressing, solvent extraction, and ultrasonic-assisted extraction, on physicochemical properties, fatty acid composition, and the contents of beneficial lipid concomitants and volatile components in tomato seed oil. The results showed that the contents of fatty acid, tocopherol and phytosterol in tomato seed oils obtained by different methods differed significantly (P < 0.05), with the highest total phenol content (88.43 mg/kg) being in the hot-pressed oil and the highest contents of tocopherol (707.26 mg/kg) and sterol (2442.66 mg/kg) being in that obtained by ultrasound-assisted extraction. The results of gas chromatography (GC) and Fourier transform infrared spectroscopy (FTIR) showed that extraction was more favorable for the retention of unsaturated fatty acids than pressing, and hot pressing was more likely to induce the production of secondary oxidation products such as aldehydes and ketones; by headspace-gas chromatography-mass spectrometry (HS-GC-MS), 38, 42, 32 and 32 volatile components were identified in the oil samples obtained by cold pressing, hot pressing, solvent extraction, and ultrasonic-assisted extraction, respectively, with the major ones being aldehydes (7.47–18.09 μg/g). By principal component analysis (PCA) and cluster heatmap analysis, the four samples were clearly distinguished from each other. The conclusion of this study can provide a theoretical basis for the quality control of tomato seed oil.