Abstract
Achieving a homogeneous final salt content in salted meat products with anatomical integrity, such as loin or ham, represents a milestone due to salting is influenced by multiple product and process factors. Therefore, meat industry demands non-destructive techniques for quality control purposes in the salting process. The main aim of this work was to evaluate the feasibility of using low-intensity ultrasound for characterizing the salting process of pork meat products.
Individual muscles (Biceps femoris and Longissimus dorsi) and whole pieces (ham) were salted by brining (20% NaCl, w/w) and/or dry-salting at different times (up to 16 days) and 2 ºC. Moreover, samples with preset salt content were formulated from minced Biceps femoris. The ultrasonic velocity (1MHz) was measured before and after salting by through-transmission method. In addition, the salting process was on-line ultrasonically monitored by conducting through-transmission and pulse-echo measurements.
Salting involved an increase of the ultrasonic velocity due to the coupled water loss and salt gain, being the influence of salt gain larger than that of the water loss. For all the tested products, salting involved a similar increase of the ultrasonic velocity, approximately 13.6 m/s per 1% salt content increase (wet basis). The salt gain in Biceps femoris and Longissimus dorsi was estimated with an average prediction error of 0.48% (wet basis). The ultrasonic on-line monitoring of the salting process by only computing the time of flight could be considered a reliable tool for quality control purposes of individual muscles and whole meat pieces.
