Seed oils, not as nutritionally fit, are better than you think. Cold-pressed oils have a shorter shelf life, expelled by a cold-pressed method, whereas refined oils with a longer shelf-life use heat/chemicals to alter their chemical makeup.
Cold-pressed method, nothing is taken out nor it is wasted. Deep earthy color and the viscosity is thicker. This is what you would use with heavy flavored ingredients and raw vegetables, and you only need just a little since the flavor is more intense. You would use this for bread dipping, charcuterie, olives, light tapas-style meals. Once they are expelled, its shelf life is short and the flavor goes stale, and then rancid. Where the color would go from deep rich to brown and oxidized with a bad smell.
Refinery process, strips nutrients and has deep golden or lighter color and the viscosity is thinner. High smoking point for deep sautés and deep-frying for wok cooking and deep-fry machines. Tastes of the oil is never discovered since it doesn't get absorbed in the food, and you can use a lot of it. These have longer shelf lives since they are refined under heat, call it pasteurization, but when they are past their date they will go rancid, and have a bad taste. The color would go dark yellow, and sometimes the oil is like that already so it can be undetected.
What are some examples of seed oils?
Seed oils include soybean, safflower, sunflower, sesame, grapeseed, rapeseed, corn, vegetable, and canola.
What can you do with seed oils?
With a high smoking point, soybean, sunflower, corn, vegetable, and canola are best for deep frying. Sesame and grapeseed oils are flavorful in salad dressings and a great addition to light sautés or tasty as finishing oils. With their intense flavors, a slight drizzle is best.
How are flavored finishing oils used?
A slight drizzle of flavored finishing seed oils like pumpkin, cumin, and specialty seeds are game changers to sauteed veggies or topped on popcorn.
Some oils on the "unhealthy list," such as cottonseed, palm, and palm kernel, have a bad rap. You can use them sparingly if you have them in your cupboard, then step away from purchasing them afterward. You can find cottonseed, palm, and palm kernel oils in junk foods like pizza and potato chips, processed foods, and specific cultural foods. "Palm oil, a hot button for controversy, is not environmentally friendly and contributes to deforestation in some countries, ultimately leaving animals without shelter." ( https://www.wwf.org.uk/updates/8-things-know-about-palm-oil) Keep in mind these are fats, and they are some of these oils that are still not healthy in large quantities, always balance.