Effect of rosemary extract on walnut oil (Juglans regia L.) oxidative stability microencapsulated by spray drying

MARTÍNEZ, MARCELA LILIAN; ROCCIA, PAOLA; LLABOT, JUAN MANUEL; PENCI, MARÍA CECILIA; MARÍN, MARÍA ANDREA; RIBOTTA, PABLO DANIEL; MAESTRI, DAMIAN

Congreso; IV Congreso Internacional de Ciencia y Tecnología de los Alimentos; 2012

The objective of this work was to evaluate the oxidative stability of microencapsulated walnut oil (WO), with and without -rosemary extract (RE)-, under prolonged storage conditions. Maltodextrin and hydroxypropyl methylcellulose were used as wall materials (WM). The solid yield and moisture content ranged between 28 and 36 % and 2.13 and 0.95% for microcapsules without and with RE, respectively. The average encapsulation efficiency was 0.71 g of oil encapsulated/g of total oil . The stability assay showed that initially, both microencapsulated and unmicroencapsulated samples (controls) did not present oxidative deterioration. However, after 90 days of storage, both WO microencapsulated and unmicroencapsulated, without and with 800 ppm of RE, showed significant increases in the formation of primary oxidation compounds, while the addition of 1600 ppm of RE effectively protected microencapsulated WO. Furthermore, the WO with 1600 ppm of RE not microencapsulated showed a significantly higher oxidative deterioration compared with it counterpart, demonstrating an additional protective effect associated with microencapsulation. These results indicate that the addition of 1600 ppm of RE to the encapsulated WO was the most effective protection way in such complex lipid system.