What is the role of roasting in sesame oil production?

Sesame belongs to the genus Sesamum in the family Pedaliaceae, with about 40 species. It’s considered a potentially rich source of nutrition, containing 35–57% oil, 20–25% protein, 20–25% carbohydrates, and 5–6% minerals. Its oil content is higher than most known oil-bearing seeds, and sesame oil is widely regarded as an affordable and high-quality product.

The quality of sesame oil is closely related to seed selection. Ideal sesame seeds should be free of contamination, mold, pests, and should be of high quality. They should have a high oil content, consistent color, and be free from mud and impurities.

After selecting good sesame seeds, roasting is necessary. Roasting is a critical step in vegetable oil production, leading to physical, chemical, structural, and sensory changes. This process boosts oil yield, lignan content and antioxidant activity, nutritional value, composition, and sensory qualities — all influenced by roasting temperature. During roasting, the seeds become more brittle.

The goal of roasting is to remove moisture and enhance the sesame seeds’ aroma and taste. Typically, roasting is done at around 170°C for about 15 minutes. After roasting, the seeds should immediately be pressed. Unlike common vegetable oils, sesame oil is usually produced through a traditional cold pressing method. This involves cooling the roasted seeds to the appropriate pressing temperature before extraction.

Once extracted, the sesame oil must be filtered to remove foreign matter and ensure purity. Filtering can be done using cotton cloth, wool, or specialized filtration equipment.

Key considerations during sesame oil processing include:

Temperature Control:

Excessive roasting can degrade nutrients and affect oil quality, while pressing at high temperatures can alter taste and color.

Moisture Control:

Water content in the seeds negatively affects both roasting and pressing, reducing the final oil quality.

Hygienic Environment:

Clean equipment and processing areas are vital to ensure the safety of sesame oil.

By strictly controlling each step of the process, it’s possible to produce sesame oil that is both nutritious and uniquely flavorful.