Effect of processing on antioxidative capacity of seafood muscle during a simulated gastrointestinal digestion

Abstract

Reactive oxygen species (ROS) are free radicals and non radical oxygen species which are unavoidably produced in the body. Oxidative stress represents a disturbance in the equilibrium status of pro-oxidants and antioxidants reactions in favor of the pro-oxidants. In living organisms and the condition can damage cellular lipids, proteins, or DNA. By far the most important defense mechanism against oxidation is the presence of antioxidants. The health aspects of seafood have primarily been linked to long-chained polyunsaturated fatty acids. However, numerous studies have reported that seafood contains additional beneficial bioactive compounds, such as antioxidants. The objectives of this study were to investigate changes in antioxidative capacity (AOC) of saithe and shrimp muscle during a simulated gastrointestinal digestion, in particular the effect of traditional household and industrial processing. The AOC of seafood muscle was evaluated by two the methods ORAC (oxygen radical absorbance capacity) and FRAP (ferric reducing antioxidant power). Additionally, the degree of hydrolysis during digestion was determined. Levels of free and total amino acids were also measured at selected time points. AOC of seafood muscle increased throughout the gastrointestinal digestion. The total increase at the end of digestion of the samples was between 20- and near 40- fold when measured by ORAC. The FRAP assay revealed a similar trend, only with significantly lower values. A concurrent rise in degree of hydrolysis was also recorded. The composition of amino acids in the muscles may be an important feature for the release and activity of the antioxidative species. The current study concludes that AOC of saithe and shrimp muscle increase throughout gastrointestinal digestion. Effects of household preparation of saithe were minimal to levels of AOC, and the processing of shrimps had virtually no effect to levels of AOC.