Chemical interaction between white onion, as natural antioxidant, on shrimp stored under freezing

Abstract The impact of white onion as a natural antioxidant on the lipid profile of “Vila Franca” shrimp (Litopenaeus schmitti Burkenroad, 1938), during storage under freezing, was evaluated by changes in the composition of fatty acids, carotenoids, centesimal composition and phenols. The lipid content in the shrimp samples in natura and with white onion was dimmed after 45 days of storage under freezing. At zero time and during storage, lower levels of fatty acids were detected in the shrimp with addition of white onion. There was a reduction in the total carotenoid content of fresh and white onion shrimp samples after 45 days of storage, corresponding to 30% and 43%, respectively. After 90 days of storage, was detected a loss of 28%, in the samples with addition of white onion, in relation to 45 days. In spite of the linear increase in phenol content during storage, no positive correlation was observed between the concentrations of phenols and the antioxidant activity exerted by white onion, in relation to the profile of fatty acids and carotenoids of the food.