Estimating the effect of different factors on the digestive bioaccessibility of protein by the Senegalese sole (Solea senegalensis); combination of response surface methodology and in vitro assays

Abstract

The present work uses a novel approach to develop a mathematical model explaining the effect of three main factors - temperature, total reaction time and enzyme:substrate ratio - in the hydrolysis of protein by the intestinal enzymes of the Senegalese sole. The methodology combines a factorial design based in the Response Surface Methodology and in vitro digestibility assays adapted to the physiology and culture conditions of the species. The model revealed that, within the physiological ranges considered in the study, the efficiency of protein hydrolysis by the intestinal enzymes of the sole was linearly correlated to two of the selected factors; directly to incubation time and inversely to the amount of substrate. The effect of temperature was not linear but quadratic, hence showing a maximum at 23°C. The information obtained can be used as a tool to maximize the biological response under variable conditions and may orientate some on-farm feeding practices.