Stability of ascorbic acid and other vitamins in extruded fish feeds

Abstract

Alternative sources of ascorbic acid (vitamin C) have recently been proposed as a solution to the problem of instability of this vitamin in aquaculture feeds. Several of these forms were tested for stability in main types of feeds. In addition, the stability of other vitamins was investigated in a catfish feed. Ascorbyl monophosphate and ascorbyl polyphosphate were found to be quite stable, i.e. retentions were higher than 90% in the stored extruded feeds and above 85% in the stored semi-moist feeds. Coated forms of vitamin C were unstable. Retentions were around 50% after extrusion, and below 16% in the stored fish feeds. Losses of the other vitamins in the catfish diet were small. © 1994.