Shear and longitudinal ultrasonic measurements of solid fat dispersions

Abstract

Dispersions of coating fat in corn oil (2.5-12.5 wt%) were prepared following two different protocols: Type A dispersions had an average crystal size of 30-36 µm, whereas type B dispersions were less than 1 µm. In both dispersions the fat crystals were aggregated into larger structures (up to 80 µm). The longitudinal ultrasonic properties (i.e., velocity, attenuation, and reflectance) were linearly related to the solid fat content, but only attenuation was sensitive to the different microstructures. The velocity and reflectance measurements were modeled using the Urick equation. Shear ultrasonic reflectance and oscillatory viscometry were used to measure the dynamic viscosity of all dispersions. According to both methods, type B samples were always more viscous than type A at a similar solids content. The correlation between the two techniques was good (r 2 > 0.99), but the numeric agreement was different for both systems.

Influence of Ultrasonic Waves on the Processing of Cotton with Cationic Softener

“…Large particles of softener are subjected to surface erosion (via cavitation collapse in the surrounding liquid) or particle size reduction (due to fission through interparticle collision or the collapse of cavitation bubbles formed on the surface). This causes the breaking of agglomerates and aggregates in the softener solution [35][36][37][38].…”

Optimizing the use of power ultrasound to decrease turbidity in whey protein suspensions

“…In the food industry, ultrasound has been used to monitor (Saggin & Coupland, 2004;McClements & Povey, 1992, McClements, Povey, Jury, & Betsanis, 1990Martini, Herrera, & Marangoni, 2005;Martini, Bertoli, Herrera, Neeson, & Marangoni, 2005a,b: Ueno, Sakata, Takeuchi, & Sato, 2002Ueno, Ristic, Higaki, & Sato, 2003) and induce (Higaki, Ueno, Koyano, & Sato, 2001;Martini, Suzuki, & Hartel, 2008) lipid crystallization, to induce the crystallization of sugars and ice (Chow, Blindt, Chivers, & Povey, 2003;, to evaluate the rheology of food materials (Mert & Campanella, 2007;Maleky, Campos, & Marangoni, 2007), and to reduce the size of polysaccharide molecules (Wu, Zivanovic, Hayes, & Weiss, 2008;Kasaai, Arul, & Charlet, 2008;Kjartansson, Zivanovic, Kristbergsson, & Weiss, 2006;Baxter, Zivanovic, & Weiss, 2005). Other potential food applications of US include pasteurization, emulsification, de-foaming, and de-gassing of soft food materials.…”

In situ monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics

“…A number of publications have demonstrated the usefulness of ultrasound in food research, including particle size determination, creaming, crystallization, and aggregation phenomena in emulsions (2,3). Ultrasound also has been used to characterize the rheological behavior of solid fat dispersions and xanthan/sucrose mixtures (4,5) and to calculate the percentage of frozen material in foods (6). The ultrasonic velocity of a fatty material increases as its solid fat content (SFC) increases; hence, ultrasonic velocity measurements can be used to determine SFC of emulsions and bulk fats (7)(8)(9)(10)(11)(12)(13).…”