Within the project: Improving the quality of meat products with on-line optical sensors, the Institute of AgriFood Research and Technology (IRTA) has worked together with the companies Boadas 1880 SA and Embotits Salgot SA. The objective is to study the viability of the Low-cost pocket NIR technology in order to obtain physical-chemical parameters on/in-line such as fat content, moisture, water activity of dry fermented meat products, so that they help ensure a regularity in its composition, as well as anticipating the emergence of technological or food safety problems. The project has studied with Boadas 1880 SA the most appropriate procedure to determine the fat and moisture content of two types of mass of dry fermented meat product (llonganissa and chorizo) in an industrial environment using the SCiO pocket NIR equipment. It is analysed how the error in the determination of these parameters varies depending on whether the spectrum is taken at the exit of the kneader or after reducing the particle size and homogenizing the sample of the mass by means of a mincer. With Embotits Salgot SA it has been studied how the taking of the NIR spectrum on the surface of a dry fermented meat product (fuet) during the drying process can help to interpret the water content and water activity.

In the case of llonganissa and chorizo, the results show that collecting the dough from the kneader and homogenizing it by chopping allows to reduce the error of prediction of the parameters of fat and moisture of the dough. However, it must be said that with the mass coming out of the kneader, a very good ratio of the NIR spectrum has also been obtained in both parameters in the Llonganissa Pagès product. In the case of the fuet, the results have given low prediction errors due to the determination of water activity on the surface and inside.

Predicting these parameters using the NIR may be useful for monitoring the drying process. A relationship between the water activity measured at the surface and that measured inside the product has been obtained. The estimation of the water activity inside the product from the NIR measurement on the surface is considered feasible as long as the initial characteristics of the product (composition, diameter, chopping, …) and the conditions of the process (temperature, relative humidity, ventilation) are the same in the different production batches that the measurement is to be made.