The first step in processing sunflower is to properly prepare the seed for oil removal. The seed is cleaned using magnets to remove metal and screening to remove impurities that can interfere with the process. The seed can be dehulled by cracking and removing the shell or can be sent to pressing with the shell still intact. Prior to mechanical pressing, the seed is heated and dried. Mechanical pressing removes approximately half to three quarters of the oil prior to solvent extraction.
The seed is mechanically pressed (pre-pressed) to extract approximately half to three quarters of the available oil so that the solvent extraction can be run more efficiently. This is typical for seeds containing more than 20% oil. The solvent extraction process uses hexane or other solvents to wash the sunflower oil from the prepared flakes. The design of the equipment varies so that Crown can optimize the amount of solvent and bed depth needed to efficiently wash the flakes, the contact time of the solvent and flakes and the power and utilities needed to run the equipment. Sunflower is processed with the Model III Extractor.
Once the oil has been removed by the solvent, the solvent must be removed from both the flakes and the sunflower oil. Heat and steam are used to strip and recover the residual solvent from the flakes. A distillation system is used to recover the solvent from the sunflower oil. The desolventized flakes are then a product and ready for sale as a good source of protein. The sunflower oil can be further refined from a crude product to an edible product.
Oil Refining and Processing
Extracted and desolventized sunflower oil must be further processed to make an edible product. Edible oils are refined to improve the flavor, odor, color and stability using processes that degum, neutralize, bleach and deodorize the oil. These refining processes remove contaminants such as phosphatides, free fatty acids and pro-oxidants.
Further processing of oils and fats is sometimes desired. Some oils are winterized or dewaxed and some are modified to change melting characteristics. Byproducts may be further processed to create value-added products or reduce costs.
Biodiesel is a renewable fuel derived from fats and oils. Although any source of fat can be used, sunflower is one of the oils used in this industry.
There is a significant number of oleochemicals made from the byproducts of sunflower oil processing. Whether it’s glycerin from a biodiesel plant or fatty acids from a fat hydrolysis plant, Crown offers many different processes to add value to these fat byproducts.