Browsing by Author "Rotikko, Johanna"

The literature review dealed with the production of, and factors affecting the optimal processing of, traditional sauce base. Aspects of manufacturing relating to recycling and energy, such as recycling of animal by-products, were also discussed. The aim of the experimental work was to find a solution for the problem related to the opacity of the meat stock caused by a pressure cooking method. The key aim was to find the causes of opacity when the bones were pressure cooked (up to 1.5 bar) and to identify a method to prevent the occurrence of turbidity. Different cooking times, pressures and proteolytic enzyme combinations were evaluated during experimental studies. The goal was to obtain a beef-flavoured demi-glace sauce base broth with a bright appearance and as high a dry matter content as possible. Dry matter, total protein and connective tissue protein concentrations, pH and turbidity values were evaluated when comparing the results of the manufacturing methods and conditions. In addition, potential methods to improve the heat recovery systems were investigated. The dry matter of the broth consisted mainly of proteins. There was slightly faster increase in dry matter concentration at higher pressure than lower pressure. Addition of the proteolytic enzyme had the same effect. Based on this study the broth manufacturer must choose between a high gelatin content and turbidity when pursuing high dry matter content. The dry matter hydrolysed from bones by pressure cooking was almost exclusively collagen. Collagen dissolved in water while the rest of the bone proteins precipitated when heated. The construction of the heat recovery system in a small food processing company may be unprofitable. Improving energy efficiency in a small food company is challenging but possible if professionals accurately evaluate the conditions.