Protein removal from fish mince washwater using ohmic heating

Abstract

A static ohmic heating system was developed to remove protein from fish mince (threadfin bream) washwatercollected from a surimi production plant in order to improve water quality. The samples were heated under different electricfield strengths (EFS, 20, 25, and 30 V/cm) until reaching the desired temperature (50, 60, and 70oC), and further held at thattemperature for a certain time (0, 15, and 30 minutes). Heating the samples to 70oC resulted in a better protein removal whencompared to 50 and 60oC. After heating to 70oC, the samples were centrifuged. The analysis of the supernatant obtained showsthe reduction of protein, COD, BOD, TS, and TDS to 42%, 25%, 23%, 44%, and 61%, respectively. The electrical conductivityof the samples showed a linear relationship with temperature and the temperature demonstrated a parabolic relationshipwith heating time. EFS and holding time have no significant effect on protein removal.

Keywords

• electrical conductivity
• ohmic heating
• protein
• surimi
• wash-water
• waste recovery