Extraction and oxidative stability of chia oil

BORDÓN, MARÍA GABRIELA; ROMINA BODOIRA; A. GONZÁLEZ; MARIA CECILIA PENCI; PABLO RIBOTTA; MARCELA MARTINEZ

Jornada; 1er. Encuentro de Investigación en Granos Iberoamericanos y 7º Seminario de Actualización en Chía; 2021

Introduction: Chia (Salvia hispanica L.) is a crop of high economic interest to the food industry due its nutritional and health attributes associated with the high content of omega-3 fatty acid. Chia seed contains between 0.25 and 0.38 g oil/g, where the major constituents are triglycerides, in which α-linolenic and linoleic fatty acids represents the 61.8 and 20.1 %, respectively. Chia oil can be consumed directly 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. Objective: The objectives of this research were to: i) study the effect of screw pressing extraction parameters on chia oil yield and quality; ii) evaluate the effectiveness of natural antioxidants alone and/or in combination and microencapsulation process on the oxidative stability of chia oil.Materials and Methods: Chia oil extraction was carried out using a Komet screw press (Model CA 59 G, IBG Monforts) (Martinez et al., 2012). The spray-drying and freeze-drying processes were performed in a laboratory-scale Mini Spray Dryer Büchi B-290 (Büchi Labortechnik AG) and in a freeze dryer (Rificor L-T8) (González et al., 2016), respectively. In all cases the oil chemical quality was evaluated. Results: The maximum oil yield was achieved under the following conditions, 0.113 g/g dry solidsseed moisture; 20 rpm pressing speed and 6 mm restriction die of the press. The oil chemical quality was not adversely affected by the extraction process. The oil storage in containers with light-barrier properties, together with the addition of ascorbyl palmitate and tocopherols (200 ppm each), could maintain chia oil quality at least up to 10 months under 25 °C. The microencapsulation process allowed obtaining omega-3 rich powders that can be used as ingredient for enriched foods. The oxidative stability during the storage of bulk and encapsulated chia oil for 90 days shows that wall matrix protects chia oil against oxidation.Conclusions: The screw pressing technology displayed chia oils with accepatable chemical quality. Microencapsulation procedure increased chia oil shelf life of about 30 to 48% during the storage period. This development provides important advances in order to evaluate the possibility of incorporating this oil into processed foods, particularly in baked products.Acknowledgement /Financial support: The authors acknowledge financial support from CONICET, FONCYT and SECyT-UNC.