Soybean Oil Processing Plant Manufacturers

Soybean oil processing — process requirements

Soybean oil processing differs from other vegetable oils in two important ways. First, soybeans have a relatively low oil content — approximately 18–22% oil in the whole bean. This means mechanical pressing alone is economically inefficient compared with oilseeds with 30–50% oil content (sunflower, rapeseed, groundnut), and most commercial soybean processing uses solvent extraction (using hexane) as the primary extraction method, or a pre-press followed by solvent extraction. The pre-press step mechanically extracts some oil (reducing the load on the solvent extractor) and prepares the soybean flakes for efficient hexane contact. Second, soybean crude oil is high in phospholipids (lecithin), which form a gum that must be removed early in the refining process. Degumming — treating the crude oil with water or acid to hydrate and precipitate the phospholipids — is an essential first step in soybean oil refining. Commercial soy lecithin is produced as a by-product of the degumming stage. The soybean meal by-product (containing 44–48% protein) is the world's most important source of protein for livestock feed.