Determination of the Fat Content of Beef using Microwave Methods
Special Symposium - Innovations in Food Technology (LMC Congress)
Modern Analysis: Chemical & Multivariate Analysis (Food-6a)
Keywords: Coaxial probe, fat content, meat, permittivity measurement, transmission line.
Beef products constitute an important group of meat products available in the market place. The fat content of beef is of considerable importance, both nutritionally and in terms of its perceived effects on eating qualities. Nutritionally, beef is an excellent source of the essential amino acids and of certain minerals, but considerable scientific evidence and public perception link the quantity of dietary fat intake to the development of coronary heard diseases and other illnesses. Therefore, a knowledge of the fat content of food materials is critical in many areas such as health assessment, nutritional labeling, food regulations and consumer protection for public health. Modern food handling and processing require rapid testing methods for quality control. Although chemical analysis methods are available for accurate fat content determination, there is a critical demand for the rapid in-line and low-cost determination of the fat content of food materials to provide a responsive control mechanism and efficient quality control system in food processes. In this research, experiments on beef with varying fat content have been undertaken to establish the feasibility of using microwave methods to determine the fat content of the beef.
The essence of microwave sensing relies on the wave/ material interaction, which is characterized by the relative complex permittivity. For water-containing foodstuffs in particular, microwave measurement is facilitated by the fact that the permittivity of water is much higher than organic compounds. The permittivity of a polar material, such as free water is described reasonably well by the Debye relation. Biologically, muscle tissue contains higher moisture content than fatty tissue. In this respect, the dielectric-based methods will have great potential to discriminate both respective tissues. The methods proposed in this paper derive the fat content in beef samples from the measurement of the relative complex permittivity at microwave frequencies.
Two methods are used to determine the relative complex permittivity; a transmission method and a reflection method. The relative complex permittivity is determined by calculation using the S-parameters, S21 (transmission) and S11 (reflection), measured using a vector network analyzer, a suitable cell or a probe.
The results obtained show a strong, almost linear relationship between both the real and imaginary parts of permittivity and the fat content of the meat. Plots of permittivity against fat content show good potential for the methods to be accurately calibrated.
* corresponding author : Prof Paul Ainsworth ( p.ainsworth@mmu.ac.uk)
Presented Thursday 20, 11:00 to 11:15, in session Modern Analysis: Chemical & Multivariate Analysis (Food-6a) Continued.
