The effect of refining process on the physicochemical properties and micronutrients of rapeseed oils

Abstract

Information on the physicochemical variability in rapeseed oil from different varieties during each refining process is lacking. Our purpose was to investigate the physicochemical properties, micronutrients and oxidative stability of the oil extracted from the five varieties of rapeseeds during their different stages of refining process. Increase in the acid value, peroxide value and p -anisidine value were detected in the refining, while content of tocopherols, sterols, β-carotene and phenols, which are regarded as important nutritional compounds diminished. Moreover, the loss rate of total phytosterols of all oils during neutralization (9.23–7.3%) and deodorization (9.97–8.27%) were higher than that of degumming (3.01–0.87%) and bleaching (2.75–1.18%). Deodorization affected total tocopherols contents the most, followed by bleaching, neutralization and degumming. There was a remarkable reduction in total content of phenol, β-carotene and oxygen radical absorbance of all oils during refining. The accumulated information can be used in looking for the optimum condition to meet the basic requirements for oil and minimize micronutrients losses so as to increase their market value.

Influence of refining processes on the bioactive composition, in vitro antioxidant capacity, and their correlation of perilla seed oil

“…The neutralization step led to an elimination of 11.3% of the remaining total phytosterols. Wu (2019) observed that the reduction of phytosterols was a result of micelle formation (of free sterols and soap) during neutralization. In addition, the losses in the degumming and bleaching steps were 6.6% and 1.9%, respectively.…”

“…The method used to analyze the content of phytosterols was based on the previous procedure with slight modifications (Wu et al., 2019). Accurately, 100 µg of 5α‐cholestane was diluted as an internal standard to a 2 mg/mL solution in chloroform.…”

“…The oxygen radical absorption capacity (ORAC) of PSO was measured based on the method described by Wu et al. (2019) with some modifications. Briefly, fluorescein was diluted in 75 mM phosphate buffer (pH 7.4) to 70 nM and stored at –20 °C.…”

Effect of the Refining Process on Total Hydroxytyrosol, Tyrosol, and Tocopherol Contents of Olive Oil

“…As already mentioned for phenolic compounds, for tocopherol only a few studies have evaluated the impact of the refining process on its content in olive oil samples, while most published articles are focused on other types of vegetable oils [30][31][32]. In general, a continuous decrease of tocopherol content has been observed during the refining procedure in sunflower, rapeseed, and soybean oils [6,33].…”

Chemical Profiling of Roasted Mustard Oils of Khokana, Nepal

“…Rapeseed oil is a major source of vegetable oil in the world. Its production is estimated at 27.71 million metric tons, the third just behind palm and soybean oil, supporting the 2018 official data of the United States Department of Agriculture [12]. It contains around 1.5-6% palmitic acid, around 0.5-3.1% stearic acid, around 28% oleic acid, around 11-23% linoleic acid, and around 5-13% linolenic acid [13].…”