Interactions between size reduction and thermal processes during treatment of animal by-products
¹Competence Centre of Food and Fermentation Technologies Akadeemia tee15A, 12618 Tallinn, Estonia; *Correspondence: urmas@tftak.eu
²Institute of Veterinary Medicine and Animal Sciences Estonian University ofLife Science, Kreutzwaldi 64, EE51014 Tartu, Estonia
Abstract:
Animal by-products from slaughterhouses often go through a process known asrendering to economically recover protein sources. Common raw material treatmenttechnologies are: pre-handling; reduction of the size of raw material particles; thermal treatmentwith pressure or sub-pressure impact; natural or artificial chemical treatment; fractionation(percolating, straining, centrifuging with or without thermal treatment, etc.) and handling ofmaterial fractions (dehydrating; defatting; demineralisation, etc.).Thermal treatment is a long-term process that lasts up to 90 minutes – and is the primarydisadvantage of known solutions because hot processing influences the natural properties ofproteins contained in the raw materials rendering them less valuable.Size-reduction is the most power-intensive phase rendering technologies when reproduciblegrinding conditions, short grinding times, precise results, and loss-free operation are required.The size reduction ratio of the material influences the effectiveness of the following treatmentstages (thermal impact and others) and quantitatively affects the extraction intensity ofcomponents from the pre-treated material.To maximise the efficiency of heat treatment and fractionation operations on by-products forfood, feeding, or technical purposes it is necessary to optimally design the technologicalequipment to fit within the specific requirements of the particular cooking and renderingapplication.The knowledge gained from this project will be used by designers and equipment producers ofcooking, frying, and other heat treatment systems for food, feed and technical purposes.This information will enable more accurate determination of heating times corresponding to theprocessed material properties and batch loads. Key words: animal by-products, meat-bone raw material, rendering, crushing ratio andfineness, heat treatment, heat transfer coefficients.
Key words:
fish and other food industries (Ockerman &, Processing technologies used in meat