Effect of Macrocystis pyrifera scalding on water reusing from the pre treatment cycles

In the scalding pretreatment, food is immersed in water or steam at specific temperatures and times, inactivating enzymes, reducing microorganisms, and softening tissues. This requires a large volume of water and energy, and it can generate contaminated water, limiting its reuse. Macrocystis pyrifera is a brown macroalga distributed along the Chilean coast and can be used as human food. The content of As, Hg, Cd, and Pb (µm/100 g) in the process water was evaluated after each scalding cycle of M. pyrifera. During scalding, there was transfer of As from the macroalga to the process water, while the others elements were not significant. From the first to the third scalding cycle, transferred arsenic reached 1.206 mg/L. According to Chilean regulations, the maximum environmental concentration is 0.01 mg/L, limiting water reuse from the first scalding cycle. Scalding water with arsenic should not be used for other food production processes, nor should it be discharged into the environment, because the arsenic content transforms the process water into a liquid industrial waste. It is suggested to evaluate techniques to reduce the concentration of dissolved contaminants to enable reuse, within the framework of the circular economy, making blanching more sustainable.