Hydroxytyrosol extracts, olive oil and walnuts as functional components in chicken sausages.

BACKGROUND Olive oil, hydroxytyrosol and walnut can be considered ideal Mediterranean ingredients for their high polyphenolic content and healthy properties. Three extracts of hydroxytyrosol obtained using different extraction process (HXT 1, 2, 3) (50 ppm) were evaluated for use as antioxidants in eight different chicken sausage formulas enriched in polyunsaturated fatty acids (2.5 g/100 g walnut) or using extra virgin olive oil (20 g/100 g) as fat replacer. Lipid and protein oxidation, colour, emulsion stability, and the microstructure of the resulting chicken sausages were investigated and a sensory analysis was carried out. RESULTS The sausages with HXT extracts were found to decrease lipid oxidation and to lead to the loss of thiol groups compared with control sausages. Emulsion stability (capacity to hold water and fat) was greater in the sausages containing olive oil and walnut than in control sausages. In contrast, the HXT extracts produced high emulsion instability (increasing cooking losses). Sensory analysis suggested that two of the HXT extracts studied (HXT2 and HXT3) were unacceptable, while the acceptability of the other was similar to that of the control products. Sausages incorporating HXT showed different structures than control samples or sausages with olive oil, related to the composition of the emulsion. CONCLUSION These results suggest the possibility of replacing animal fat by olive oil and walnut in order to produce healthy meat products.