Abstract
Changes in relevant quality attributes for the food industry were monitored in Saccharina latissima following pre-treatment (PT), freezing and thawing. The evaluation included the monitoring of qualitative indicators (dry weight, drip loss, texture, colour) and microbial status over a 15-month storage period, as well as the characterization of the nutrient profile. Freezing without PT led to extensive drip loss upon thawing (15 to 24 % of the initial weight) as well as structural alterations reflected by textural changes. The resulting liquid fraction contains water-soluble compounds including minerals (predominantly K), carbohydrates (mainly mannitol) and some proteins and free amino acids. Among the tested PTs, steaming resulted in reduced drip loss and higher nutrient retention compared to freshwater blanching and salting. Stable levels of fucoxanthin pigment in steamed samples along with evidence from the characterization of liquid fractions (i.e., drip loss upon thawing) by nuclear magnetic resonance (NMR) indicate that this treatment inactivates enzymes responsible for the degradation of sensitive compounds. The iodine content of fresh S. latissima may limit its use as food ingredient. Steamed S. latissima was lower in iodine than the untreated control but higher than those of blanched and salted samples. The blanching and salting treatments also resulted in extensive losses of soluble compounds highlighting the compromise between iodine content reduction and nutrient retention in kelp processing. The presented data is directly relevant to kelp producers and food manufacturers in establishing processing methods in commercial production of the kelp S. latissima.