Ultrafiltration for the recovery of proteins from surimi washing water

Abstract

The aim of this study was to evaluate the efficiency of the ultrafiltration process (UF) in the cleansing treatment of the tilapia surimi washing water and in the recovery of components. After producing surimi, the water generated in the washing operations was subjected to UF in a 30 kDa polyethersulfone membrane. Unfiltered washing waters and UF permeate and concentrate were analyzed for pH, total solids (TS) and fixed solids (FS), total proteins, and lipids. The chemical oxygen demand (COD) was determined in the original water and in the permeate. The concentrate was dehydrated in a spray dryer and analyzed for amino acids and carotenoids. The permeate showed a significant decrease in TS, proteins and COD, indicating that UF was efficient in removing the organic load from the waters. The percentage of protein recovery by UF was 93.12% and the dehydrated concentrate had all the essential amino acids, being leucine (5.47%), lysine (6.49%), valine (3.59%), and phenylalanine (3.68%) those with the highest concentrations, and also 0.67 mg/100 g of carotenoids. The application of UF has proved to be viable both in the recovery of valuable compounds and in the decontamination of water, contributing to the sustainability of the fish productive sector.

Practical Application: The application of ultrafiltration (UF) in the surimi washing waters reduced the organic matter, allowing their disposal and reuse in the industrial process, in addition to recovering potentially polluting substances. The proteins recovered by UF from the surimi washing waters contain all essential amino acids, suggesting its use as a supplement, both in the form of fortified foods and supplements itself, very popular among athletes and people with high physical activity.