Consumer Acceptability of Melanosis Levels in Western Rock Lobster by Visual Evaluation

Abstract

               A number of food products undergo browning due to enzymatic reactions that occur during processing and storage. The browning reaction has an important influence on food quality and is therefore of great importance to the food industry. The objectives of the research were to identify a visual evaluation method for determining consumer acceptability and to use the method to conduct a consumer study on acceptability of melanosis levels in western rock lobster.

              Twenty photographs of lobsters containing melanosis at various stages were selected according to the colour intensity and the area of blackening. Four extra photographs having no indication of melanosis was used as a blind control. Sixty-nine volunteers assessed the degree of acceptability of melanosis level with respect to area, colour intensity and overall acceptability on a graphic line scale. A spectrophotometer was also used to measure the colour intensity of all the photographs used in the study. The correlation between the visual colour evaluation and instrumental methods was demonstrated. There were significantly difference among samples when evaluation of area, colour intensity and overall
acceptability. 

              Consumer acceptability of melanosis levels in western rock lobster is based on area and colour intensity. Melanosis levels were found to be accepted only when occurring in a small area with low intensity. The results obtained from the consumer study showed a high correlation with spectrophotometer colour measurement (r=0.71) which indicated that the instrumental data were related to the sensory perception.