sunflower oil production
Sunflower seed belongs to oil seed with shell, with oil content of 22-40%. At present, there are two kinds of sunflower seeds: one is small sunflower seed used as oil seed, whose shell is thin, and the whole seed contains as high as 40-50% oil; the other kind is a large particle seed which is mainly for food purposes, whose oil content is about 22-35%. After shelling, the oil content of oil sunflower kernel is higher, which is about 40-67.8%, while protein content is 26-30.4%, and crude fiber content is 1.76-6%.
Sunflower seed oil contains about 80-86% of unsaturated fatty acid, so it is nutrient-rich and suitable for eaten raw. At the same time, the oil cake after pre-pressing contains up to 40-53% protein. Although it is reported that such protein contains a small amount of phenolic compounds (3-3.5%) and about 70% of it is chlorogenic acid and other harmful substances, but if processed by damp-heat treatment is a good protein resources.
How to make sunflower oil?There are 3 kinds of sunflower oil processing technology: 1. once pressing (sunflower seed kernel contains <18% shell); 2. Twice pressing (sunflower seed kernel contains less than 1-1.3% shell); 3. Pre-pressing extraction (pre-pressed sunflower seed oil cake residue oil content 12-15%).
Sunflower seed petreatment requirements
1. The necessity of shelling before pressing: reasonably reduce impurity and shell content can have great effect on oil yield, especially the shell content is worthy of more attention. Theoretically, pressing oil with sunflower seed shell is unreasonable, this is because:
- The shell has high wax content (0.4-10.7%% of the total amount of shell, accounting for about 75% of the whole seed wax content). If pressing with shell, the sunflower oil will contain more wax that pressing without shell. The oil produced with shell contains up to 0.02-0.35%wax, while the removal of sunflower seed shell will decrease this value to only 0.011-0.015%. too much wax will impact oil refining.
- The shell absorbs oil, so it is easy to cause oil loss. It is measured that, in the pressed pulp, the oil content of the shell is almost double that of cake itself. For example, in the pre-pressed oil cake whose residual oil content is 10-13%, the oil content of the shell is 24-28%; while in the oil cake whose residual oil content is 5%, the oil content of the shell is 8-9%.
- The sunflower seed shell contains up to 60% of coarse fiber, so it will affect feed and edible value. At the same time, too much shell content will increase the wear of oil press.
2. Shelling equipment: there are many kinds of shelling equipments, while the disk sunflower seed dehuller is the most widely used one. Its peeling rate is high. If you want to improve the peeling rate, you should maintain the water content at 7-8% and seed uniformity. Usually you should also pay attention to adjusting the sunflower seed dehuller rotating speed according to the raw material moisture.
3. In the process of flaking and steam cooking, we should pay attention to the regulation of water content, in order to prevent the dry roller in flaking and gelatinization in the steam cooking process.
The characteristics of sunflower seed oil pressing
Sunflower seeds oil pressing: sunflower seed kernel is soft, and like other soft oil seeds (such as peanut kernel), it has low fiber content, therefore it is easy to form oil cake or block, and the cake is solid and easy to plug the oil line. No matter you choose hydraulic oil press machine or screw sunflower seed oil press, you must pay attention to reduce water content, especially in once pressing process. While in pre-pressing process, the entry temperature should not be too high.
For once pressing, the compression ratio of screw oil press barrel shall be higher than that of pre-pressing, and the pressure in pressing chamber shall also be high. To achieve the above result, in addition to changing the barrel structure or use different types of oil presses, mixing a certain amount of fiber shell (such as chaff or 10-20% of its own shell) is also conducive to form a high pressing chamber pressure.
The twice sunflower oil pressing process: there are generally two kinds of configurations, namely: pre pressing and secondary pressing (with screw oil press); pre-pressing and hydraulic oil press second pressing. The processing parameter of hydraulic oil press is similar to that of peanut oil pressing. The particle size of sunflower seed oil pre-pressing shall not excess 1.5 mm.