Attempts of Physical Refining of Sterol-Rich Sunflower Press Oil to Obtain Minimally Processed Edible Oil

Nutrients in rice bran oil and their nutritional functions: a review

Rice is an important food crop throughout the world. Rice bran, the outer layer of rice grain, is a by-product generated during the rice milling process. Rice bran oil (RBO) is extracted from rice bran and has also become increasingly popular. RBO is considered to be one of the healthiest cooking oils due to its balanced proportion of fatty acids, as well as high content of γ-oryzanol together with phytosterols, vitamin E, wax ester, trace and macro elements, carotenoids, and phenolics. The existence of these compounds provides RBO with various functions, including hypotensive and hypolipidemic functions, antioxidant, anticancer, and immunomodulatory functions, antidiabetic function, anti-inflammatory and anti-allergenic functions, hepatoprotective activity function, and in preventing neurological diseases. Recently, research on the nutrients in RBO focused on the detection of nutrients, functions, and processing methods. However, the processing and utilization of rice bran remain sufficiently ineffective, and the processing steps will also affect the nutrients in RBO to different degrees. Therefore, this review focuses on the contents and nutritional functions of different nutrients in RBO and the possible effects of processing methods on nutrients.

The first stage of refining of post-fermentation corn oil with a high content of free fatty acids and phytosterols - Comparison of neutralisation by an ion-exchange resin without solvent and base neutralisation

Post-fermentation crude corn oil obtained as a by-product in the production of bioethanol from maize grains is characterized by a very high content of free fatty acids. Refining of post-fermentation corn oil will give a product that will be different from the refined oil obtained by extracting oil from corn germs. From the point of view of refining vegetable oils, the neutralisation of this oil is the most important process. Anionic ion-exchange resin was used in the research in a way to avoid the use of harmful organic solvents and a comparatively standard method of neutralising free fatty acids based on the use of a sodium hydroxide solution. Ion-exchange resin can be used in the processes of neutralising vegetable oil with an average content of free fatty acids, then the oil is neutralised in miscela. In the research, no organic solvent was used, but to reduce the flow resistance, a system based on an adjustable reduced pressure in the range of 300-50 mbar was used, to maintain a constant contact time of the oil with the resin in each cycle. The aim of the research was to obtain neutral oil with a high content of biologically active substances such as phytosterols and carotenoids. Both methods showed a reduction of free fatty acids up to 93-96 % and a similar refining loss of 18-19 %. The use of an ion-exchange resin allowed to obtain an oil in which the phytosterol content increased by 5 % for β-sitosterol, by 6.3 % for ϭ5-avenasterol, and the carotenoid content was reduced by 35 %. An increase in the number of fatty acids, such as 18:1 cis-oleic acid and 18:2 cis-linoleic, was observed.

Cleaner lipid processing: Supercritical carbon dioxide (Sc-CO2) and short path distillation

Today, regulations and consumer awareness demand production technologies with minimum impact on the environment and maximum utilization of available resources. In the field of lipids, two well-known technologies for avoiding the use of organic solvents and chemicals stand out: supercritical (Sc) fluids and short path distillation (SPD). To date, both technologies involve high operating costs that have limited their application to selected high value-added products which are high temperature sensitive. However, improvements in process control and materials make further implementation of these techniques possible. In this chapter, an integrative review has been carried out with the aim of compiling the literature on the application of these technologies to lipid extraction, micronization and fractionation of liquid mixtures. Special attention has been paid to the separation of compounds by both technologies: deacidification, partial purification of acylglycerol compounds, isolation of unsaponifiable compounds and separation of toxic and polluting compounds.

Loss in the Intrinsic Quality and the Antioxidant Activity of Sunflower (Helianthus annuus L.) Oil during an Industrial Refining Process

Minor compounds in vegetable oils are of health interest due to their powerful biological antioxidant properties. In order to extend the shelf life of sunflower oil, it is generally subjected to a refining process that can affect these desirable compounds. The main purpose of this study was to determine the effect of this chemical/physical refining process on selected minor components of sunflower oil in order to establish the nutritional quality and health properties of the oil. The oxidative stability, contents of fatty acids, tocopherols, phytosterols, reducing capacity, β-carotene, chlorophyll, and squalene were studied during six refining steps. Quantitative data showed the evolution of oil quality according to its degree of refinement. The results showed a significant decrease for all of the minor compounds analyzed, with losses in carotenoids of 98.6%, 8.5% in tocopherols, 19.5% in phytosterols and 45.0% in squalene. The highest reductions were recorded for the compounds that alter the most the visual aspects of the oil (waxes, carotenoids and chlorophylls) whereas reduction was limited for the compounds with no impact on the organoleptic quality. The losses in the compounds of health interest should be minimized by improving the refining processes and/or having a greater content of those molecules in crude oil by breeding new performing varieties.