Application of Natural Antioxidants from Strawberry Tree (Arbutus unedo L.) and Dog Rose (Rosa canina L.) to Frankfurters Subjected to Refrigerated Storage

The effect of the addition of natural antioxidants from strawberry tree (Arbutus unedo L.; AU) and dog rose (Rosa canina L.; RC), in frankfurters elaborated with or without the addition of antioxidant additives (sodium ascorbate and nitrite) was studied. Six different types of experimental frankfurters were prepared depending on the addition of phenolic-rich extracts from RC and AU and the presence (P) or absence (C) of antioxidant additives. Thiobarbituric acid reactive substances (TBARS)-numbers significantly increased during chilled storage of C-frankfurters while additives and fruit phenolics inhibited lipid oxidation in P-frankfurters. The amount of protein carbonyls significantly increased in all treatments except in P-AU frankfurters. The discoloration process that occurred during the chilled storage was reduced by the addition of substances with proven antioxidant activity (P-frankfurters). Texture characteristics as hardness, springiness, cohesiveness and gumminess also suffered a significant deterioration in C-frankfurters. The use of phenolic fruit extracts in combination with traditional antioxidant additives is a successful strategy to enhance the oxidative stability of frankfurters without modifying their color and texture properties.