Nowadays, tropical plants oils (e.g. palm oil and coconut oil) are extensively used in consumer products, especially in infant formulas. However, there is a lack of statistical data about the levels of mineral oil in tropical oils, including saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH). In this study, we reported a survey of MOSH/MOAH in tropical oils. Meanwhile, we provided an effective strategy to reduce the content of MOSH/MOAH. A total of 708 tropical plant oils were collected from five tropical countries for this survey. The highest quantifiable MOSH and MOAH concentrations were up to 455.99 mg kg-1 and 78.87 mg kg-1, respectively. Thereinto, MOSH was ubiquitous in almost all the tested samples. The distribution of sub-fractions for MOSH was centered at C25-C35 and C35-C40 for most crude and refined oils. After distillation, the MOH sub-fraction ≤C40 could be removed effectively, but there was no effect on the sub-fraction >C40.

Free phytosterols (PS) and phytosterol esters (PSE) usually coexist in natural oils, which significantly affect the crystallization behavior of oil. However, the phase behaviors of PS/PSE mixtures in oils and their roles on the crystallization behavior of oil are still unclear. In this study, the dissolution and crystallization behaviors of PS/PSE mixtures in medium chain triglyceride (MCT) were studied, and the synergistic mechanism of PS/PSE mixtures on the crystallization behaviors of MCT was further clarified. The results showed that when the mass ratio of PS: PSE was greater than 3: 7, PS/PSE mixtures recrystallized a new urchin-like crystal structure, which was different from PS spherical or PSE plate-like crystal structure, in MCT. The new urchin-like PS/PSE crystal had a larger surface area, and its melting point was between PS and PSE. It also showed the synergistic ability to promote the crystallization nucleation of MCT. When the total content of PS and PSE was 1 wt%, and the mass ratio of PS: PSE was 5: 5, the crystallization peak temperature of PS/PSE/MCT was 12 ºC higher than that of virgin MCT, 2.5 ºC higher than that of PSE/MCT, and 10.3 ºC higher than that of PS/MCT. These results not only provide a method for obtaining new crystal structure of phytosterols, but also have great significance for controlling the crystallization behaviors of oils by precisely adjusting the nutritional composition of oils.

Trans fatty acids (TFA) have been shown to be associated with various health disorders. The major source of dietary TFA is high-temperature deodorization of vegetable oils. In this study, precision minimal deodorization was proposed to obtain healthier zero-TFA vegetable oils. Dual columns with dual temperatures (DCDT) deodorizer was designed, transformed and industrially implemented among dozens of plants. Also the deodorization temperatures were optimized and customized respectively for four kinds of vegetable oil (soybean oil and rapeseed oil: tray column 205°C and packed column 225°C, maize oil and sunflower seed oil: tray column 210°C and packed column 230°C). Four kinds of oils can all achieve zero-TFA by DCDT deodorization at the customized temperatures, and meanwhile oil qualities and shelf life stabilities were compared with corresponding conventional refining oils. The initial FFA and color were a little higher than conventional refining oils, however, they showed no significant differences in odors and shelf life stability, which indicated a good and stable oil quality of zero-TFA oils for future industrial productions and sales.