Oxidative Stability of Chia Oil: Its Potential Application in Food

Abstract

Chia (Salvia hispanica L.) is a crop of high economic interest to the food industry due to its nutritional and health attributes. The high essential fatty acid contents of the chia seed make it a good source for commercial production of edible oil. Oil content is as high as 380 g/kg seed where the major constituents are triglycerides, in which polyunsaturated fatty acids, linoleic and α-linolenic acids are present in high amounts, 20.1 and 61.8% respectively. Omega-3 fatty acids play an essential role in physiology, especially during fetal and infant growth, and in the prevention of cardiovascular diseases; they are also antithrombotic, antiinflammatory and antiarrhythmic agents favoring plaque stabilization. Chia oil can be extracted easily by screw pressing. The highest oil recovery (261 g/kg seed) was achieved at 10.1 g/100g kernel moisture and 30°C pressing temperature. Fresh chia oil is very low in free fatty acid concentration (0.13 g oleic acid/g oil), hydroperoxides not being detected, k232 1.35 and k270 0.15; with an average content of total tocopherol of 717 mg/kg oil. Chia oil can be consumed directly as a salad dressing or incorporated into food products of mass consumption. Unsaturated fatty acids are chemically unstable in the presence of oxygen, light, moisture and heat, so, is important to know its oxidative stability in both systems. The addition of antioxidants and microencapsulation by spray-drying enhances stability of lipids and extends the shelf life of food containing them. Both can enhance their action under suitable storage conditions. The quality of Chia oil could be maintained at least up to 10-month (300 days) storage in containers with light barrier properties, together with the addition of ascorbyl palmitate and tocopherol, under room temperature conditions. Chia oil conservation by microencapsulation depends on the composition and structure of the established wall material, and also on the operating conditions during the production of these particles (homogenization, temperature, pH, pressure, humidity). Regarding oxidative stability, microencapsulation protects against chia oil oxidation during storage at least up to 3 months. This makes the incorporation of unsaturated fatty acids into food a significant challenge since their susceptibility to lipid oxidation and development of off-flavors affect the sensory properties of omega-3 and omega-6 fortified food.