Enzymatic extraction of oil from Baltic herring heads using protosubtilin G3x

Abstract

The article is devoted to the problem of rational and comprehensive use of fish raw materials, in particular, Baltic herring heads (sprat), and namely, obtaining biologically valuable oil. The purpose of the study is to substantiate rational modes of enzymatic extraction of food-grade oil from Baltic herring heads using the domestic enzyme protosubtilin G3x. The paper shows the dependence of the oil yield and its quality indicators on such factors as temperature and duration of enzymatic treatment. Both factors had a statistically significant effect on the amount of extracted fat and its spoilage indicators (acid and peroxide values). After 180 minutes of hydrolysis, the fat yield did not increase significantly regardless of the process temperature. The highest fat yield when using protosubtilin G3x (74.2%) was noted after 4 hours of hydrolysis at 50 °C, slightly less (72.3%) after 3 hours at the same temperature. By increasing the temperature to 60 °C, the process was intensified at the initial stage, but after 120 minutes of hydrolysis, no further decrease in the oil yield was recorded. The article presents the results of studies on the effect of the fineness of grinding of fish raw materials under a rational mode of the enzymatic hydrolysis process: temperature - 50 °C; duration – 180 min. The oil yield was 79.6% and 62.4% of its initial content for Baltic herring heads, ground, respectively, in a grinder and in a homogenizer. As a result of the studies, the following rational parameters for enzymatic extraction of fat using protosubtilin G3x have been established: temperature – 50 °C; duration – 3 hours. It has been shown that grinding fish heads in a grinder before extraction is the most rational method in comparison with cutting into pieces or processing in a cutter.