Pulsed electric field processing as an alternative to warm water treatment for the reduction of potentially toxic elements in Saccharina latissima

Sammendrag

The kelp Saccharina latissima is characterised by high iodine concentrations. This can lead to adverse health effects if consumed in excess and represents a market barrier for cultivated kelp as food. Other potentially toxic elements (PTEs), including arsenic, cadmium, lead, and mercury, may also be present, and their concentrations should be minimised to ensure safety compliance. Therefore, efficient processing methods for PTE reduction which retain flavour and nutritional value are needed. Warm water treatment (WWT) has been shown to reduce iodine concentrations significantly. However, it is energy-demanding. This study aimed to evaluate pulsed electric field (PEF) as an alternative to WWT for processing of S. latissima. Three levels of PEF were tested, determined by increasing pulse counts (200, 500, and 800). Chemical analyses of PTEs, minerals, and amino acids were used to calculate mass balances and true retention (TR) values to assess the impact of the processing on the nutritional value, flavour, and safety of the seaweed. PEF processing and WWT resulted in similar dry matter and mineral losses. PEF processing at the highest level resulted in a 25% reduction in iodine concentration. However, this was not significantly different from the 19% reduction in WWT samples. TR values indicated that PEF processing could be more efficient at removing lead content than WWT. Protein was better retained during PEF processing than WWT, especially at the lower levels. PEF processing at the highest level could be a low-energy alternative to blanching, with similar iodine reduction, higher protein retention and lower lead retention.