Acoustic techniques to detect eye formation during ripening of Emmental type cheese

Abstract

For eye forming cheeses such as Emmental, Gouda, Maasdam and others, ripening is the critical stage in which eyes and other sensory properties develop. For this type of cheeses, it is relevant to detect when eyes appear and when they have reached their optimum size and number. This article presents an interdisciplinary approach to detect and monitor eye formation in Emmental type cheese by using an acoustic technique. Two digital signal processing methodologies were studied: first order momentum of the spectrum and signal cross-correlation. Acoustic results were compared with two destructive standard methods (texture analysis and humidity determination) and evaluation of photographs of cheese wheels cut in half. Results show that acoustic parameters allow to detect different stages of eye formation and their results are consistent with information obtained from cheese images. Acoustic evaluation proves to be a non-destructive method to monitor eye formation in Emmental type cheese ripening. Industrial relevanceThe development of non-destructive monitoring techniques for cheese ripening help manufacturers to monitor the ripening process without damaging cheese wheels in the process. In particular, for eye forming cheeses is relevant to detect when eyes form, and when they start to overgrow in order to stop ripening. Acoustic techniques are used along with destructive techniques in traditional cheesemaking to detect internal defects and assess the maturation stage of the product. In this work, we propose the systematization and analysis of the acoustic response to an impact on eye forming cheeses. Experiments were performed on Emmental type cheese wheels during their ripening. Results showed that cross correlation of acoustic signals and first order momentum of the acoustic spectrum help in detecting eye formation and when eyes start to overgrow in Emmental type cheese. This study is a first approach in developing a systematic, non-destructive acoustic monitoring technique that can be used by cheesemakers at industrial scale.