2017

Vikman, Minna; Siipola, Virpi; Kanerva, Heimo; Slizyte, Rasa; Wikberg, Hanne

Large amounts of bones and trimmings are generated as a by-product of the poultry industry in mechanical deboning of chicken. These by-products are potential sources of valuable components such as proteins and nutrients. Enzymatic hydrolysis of animal by-products can be used to separate lipids and produce protein hydrolyzates resulting in the formation of insoluble sediment rich in phosphorus and nitrogen. In this study, the sediment from the enzymatic hydrolysis of by-product from mechanical deboning of chicken is hydrothermally treated to evaluate the possibility for nutrient recycling. Hydrothermal processing was performed at elevated temperature of 150°C and 220°C using water as the reaction medium with varying pH and time. The elemental composition of the liquid and solid fractions was measured after the treatments. With higher pH, the majority of phosphorus was distributed to the solid fraction while with pH 1 the majority of phosphorus was found in the liquid fraction. Nitrogen was concentrated in the liquid fraction in all processing conditions. The major part of the carbon was distributed to the liquid fraction.