Search

The objective of this study was to develop a numerical model to characterize wear behavior of solid fats with different crystalline networks. Wear behaviors of three different fats (cocoa butter [CB], anhydrous milk fat [AMF], and palm oil [PO]) crystallized at three temperatures (dependent on fat type) and two cooling rates (0.1 and 15 °C min−1) were evaluated under several normal forces (0.3–2.0 N) at room temperature (20 °C). A numerical model for penetration depth that accounted for both deformation and removal of material due to wear was developed. All models had mean absolute error

Soft solid foods commonly undergo processing steps such as extrusion, slicing, and shredding. Food tribological behaviors, especially wear behaviors, may be a good indication of their ability to be successfully sliced, shredded, or extruded. However, food wear behaviors are currently unknown. Thus, the objective of this study was to characterize the wear behavior of gels with different structures using a numerical model. Wear behaviors of whey protein isolate and κ-carrageenan gels were evaluated under several normal forces. An empirical model for penetration depth was developed that accounted for deformation due to applied force and removal of material. All models had mean absolute error

The glass transition temperature (Tg) is an important property that influences the processing and textural characteristics of candy. Measurement of Tg is done by comparably expensive and complex instruments. In this study, we tested a new system which uses capacitance thermal analysis (CTA) of candy trapped between stainless plates, as the system is caused to heat at an uncontrolled rate. The data of capacitance as a function of temperature were processed by a genetic algorithm (GA), and fitted to a three-section model to determine Tg. Tg of the candies were independently measured by DSC as a reference. The results showed that when the Tg of the candy was below ∼15 °C, the measurement from the GA-CTA was higher (2–3 °C) than that from DSC. However, if Tg of the candy was higher than 15 °C, the two methods gave similar values. GA based CTA provides a feasible new way to measure phase transitions in candies with relatively inexpensive equipment, and with less need for user interpretation of data.

Hydrogels are used in multiple industries; although hydrogel deformation and wear behaviors can be a good indicator for their functionality, there are no available models for characterizing hydrogel deformation–wear behaviors. This study characterized wear behaviors of casein (3–5% w/w, 200 mM NaCl), κ-carrageenan (0.8–1.2% w/w, 100 mM NaCl), and whey protein gels (13% w/w, 50–150 mM NaCl) at room temperature (20 °C) under several normal forces (0.1–1.5 N). A kernel-based model was used to characterize hydrogel wear behavior by separating the deformation–wear process deformation-dominant, constant wear rate, and failure regions. Higher normal force and lower polymer concentration showed higher constant wear rates and lower durability. The kernel model was able to characterize hydrogel wear-deformation behaviors and is useful for industrial applications.

Tomato puree was processed by continuous high-pressure (CHP) homogenization at 69–276 MPa, for 1–3 passes. Laser scattering and light microscopy showed CHP reduced the pulp particles to ∼10–100 μm, producing smaller and more uniform particles, with processing at 276 MPa and 2 passes producing greatest particle reduction. No differences in moisture or color were found due to different treatments. In general, G ′ > G ″ for all samples, suggesting a soft gel network. Both the storage modulus ( G ′) and loss modulus ( G ″) decreased with CHP pressure. G ′ decreased modestly with frequency between 0.1 and 2 Hz, and more dramatically between 2 and 30 Hz, with behavior characteristic of entangled polymers. In general, yield stress decreased with homogenization pressure, but increased with number of passes. CHP-treated samples had lower consistency and were less shear-thinning than the control. Repeated passes increased the consistency of CHP samples. The results suggest CHP processing produced smaller and more uniform particles, causing a reduced level of microstructure that contributes to elastic properties at small deformation.