Analysis of the simultaneous measurement of acoustic phase velocity and stress-strain relationship in beef: An approach to Young's modulus

Abstract

Ultrasound is a tool that has two fields of study and application. On the one hand, the characterization of materials by means of low intensity ultrasound (LIU) and on the other, the modification of materials by applying high intensity ultrasound (HIU). In the last decades ultrasound has been applied in the food industry. The LIU is primarily applied as an evaluation system to determine the quality of food. In the meat industry, medical ultrasound has been used to check the status of meat postmortem. In some cases, also, acoustic properties such as acoustic phase velocity (APV) and attenuation are determined, which is a way of predicting the texture of the meat, where the nature and strain of the samples can modify the results of the velocity values acoustic phase. However, there is no precise information on how the strain of the sample could affect the measurements. The aim of this research was to determine the effect of sample strain (%), muscle (Longissimus thoracis, LT; Longissimus lumborum, LL and Psoas major, PM) and high intensity ultrasound (HIU, 0 or 90 W/cm2) application on LIU-APV [c, m/s] measures. The factors mentioned above significantly (P < 0.05) affected LIU-APV with no interaction effect. APV is related to meat texture, muscles considered as tender resulted in lower phase velocity. However, a better relation was observed with characteristic acoustic impedance (Z) and stress. Additionally, HIU pretreatment resulted in LIU-APV decrease of ≅ 41.6 m/s. Finally, sample strain affected LIU measures with an inverse trend, the lowest LIU-APV values were found at 40% sample deformation with a 10% of APV decrease ≅ 149 m/s. LIU contact conditions should be standardized to a level where the air in the sample and the ultrasonic sensor coupling can move without causing irreversible damage to the meat sample, ultrasonic gel is commonly used, in order to couple the tissue and sensor impedances.