Effects of blanching and freezing on antioxidant capacity of dulse (Palmaria palamata), gracilaria (Gracilaria tikvahiae), sugar kelp (Saccharina latissima) and winged kelp (Alaria esculenta)

A lot of attention has been given to analyzing antioxidants present in sea vegetables, focusing on dried products. Sea vegetable producers are now marketing minimally processed sea vegetable products including fresh and frozen salads, ‘ready to eat/cook’ blanched and salted fronds, and frozen prepared soups. However, effects of processing methods on bioactive compounds present in these value-added products have been scarcely investigated. Objectives of this research were to assess effects of blanching, freezing and short term frozen storage on the total phenolic content (TPC) and antioxidant capacity of four freshly harvested sea vegetables; gracilaria, dulse, sugar kelp and winged kelp. For the brown sea vegetables, differences in TPC and antioxidant capacity between the blades and stipes were also determined. Triplicate batches of sea vegetables were processed into four treatments: fresh, blanched, frozen, and blanched frozen. Samples were blanched at 80°C for 1 min and frozen storage was for 1 month. TPC, DPPH and FRAP were conducted on freeze-dried, ground samples. Data were analyzed using JMP 12.2 at significance level of 0.05 for ANOVA and Tukey’s HSD. Blanching significantly (p

Faculty Mentor: Denise Skonberg