Production yield analysis in food processing. Applications in the French-fries and the poultry-processing industries

D.J. Somsen

Research output: Thesisexternal PhD, WU


Food processors face increasing demands to improve their raw material yield efficiency. To really understand the raw material yield efficiency of food processing, mass losses need to be divided in wanted (desired) and unwanted ones. The basic approach to increase the raw material yield efficiency is to mini mise unwanted mass losses at source. Wasting raw materials should be avoided, because the largest proportion of the overall business costs is associated with the purchase of raw materials. This wasting will therefore put the company's pro fit under pressure. From a sustainability point of view, it is also important to transform raw materials efficiently into final products. There is an increasing interest to find appropriate measures to track the yield efficiency of food processes in order to guide organisational actions to reduce unwanted mass losses. Many unwanted mass losses are hidden and need to be explored to make the management fully aware of these losses and the corresponding economic impact. Poor practice, poor maintenance, outdated equipment and technologies must first be visualised before they can be corrected.

A new dimensionless number (called Yield Index) was developed to measure the true raw material yield efficiency of a transformation process. To measure the Yield Index, a food processor should measure the actual production yield and compare this with the maximum production yield. However, for many food processors the maximum production yield is unknown because of the lack of knowledge. With a systematic approach and considerable research effort it is possible to build a model that can predict the maximum production yield with respect to raw material parameters, additions and final product specifications. This model can then be used to pinpoint unwanted mass losses in the production process. The thesis describes in a comprehensive way the development of two models to estimate the maximum production yield of French-fries production and poultry-processing (transforming broilers chickens into meat parts). These models were used in practice, to pinpoint unwanted mass losses during processing and based on this knowledge, both processes were improved significantly. Based on these two practical case studies a general system approach was developed to implement production yield analysis (PY A) in other types of food processes.

It was found that often a significant lack of knowledge in the true efficiency of the production processes exists. A PY A makes it possible to calculate the true yield efficiency of the process. This information is needed to convince management about the necessity to reduce unwanted losses. Not only to improve economics but also to improve aspects of modern sustainable food processing.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
  • Tramper, Hans, Promotor
  • Capelle, A., Promotor
Award date31 Mar 2004
Place of PublicationWageningen
Print ISBNs9789058089670
Publication statusPublished - 2004


  • food processing
  • yields
  • chips (French fries)
  • broilers
  • efficiency
  • raw materials
  • processing losses
  • models


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