Mild blanching prior to pH-shift processing of Saccharina latissima retains protein extraction yields and amino acid levels of extracts while minimizing iodine content

•Proteins were extracted from soaked and blanched (12/45/80 °C) sugar kelp.•Only blanching-45 °C gave similar yield and protein purity as the control biomass.•Blanching decreased protein solubility due to a higher ratio of large peptides/proteins.•Blanching-induced lowering of ionic strength increased protein precipitation.•Iodine still limits consumption of all produced protein extracts.