Critical quality constraints of sensory attributes in frankfurter-type sausages, to be applied in optimization models

A new method for constructing constraints and optimizing sensory attributes of a frankfurter-type sausage is presented. Small batches of 87 sausages with different biochemical composition and meat content were produced. The colour and firmness were instrumentally measured and modelled as mathematical functions of biochemical composition and muscle content. Ten varieties was selected based on these colour and firmness measurements and subsequently produced in larger quantities and served to consumers in order to identify acceptability limits for colour and firmness parameters of sausage. These limits together with the mathematical functions were used as quality constraints in an overall nonlinear optimization model, to find least-cost formulas that provide sausages with acceptable sensory quality to the consumer. Consumer acceptability limits of lightness defined as 60% purchase criterion were found to be between 62 and 68 (L*-CIE colour scale), based on a selection of five sausage samples. For firmness this was more complicated because of a high content of connective tissue in some of the sausage samples. It was possible to achieve the lightness and firmness preferred by the consumers without satisfying the legal restrictions for biochemical composition. In addition, the formula costs less when the solution fulfils consumer restrictions instead of legal restrictions.