Determination and Validation of Discrete Element Model Parameters of Soybeans with Various Moisture Content for the Discharge Simulation from a Cylindrical Model Silo

This study investigates the physical parameters that affect the flow patterns of soybeans with various moisture content (12% to 60%) at varying orifice sizes (20, 40, and 60 mm) in a cylindrical silo. The flow conditions required to obtain a steady mass flow during discharge were evaluated via experiments and three-dimensional discrete element method (DEM) simulation. The discharged mass flow rates at different flow conditions provided the critical size of the orifice. If the reduced diameter (Dred) of an orifice is >5.59, the flow showed a steady state. Based on the mass flow index (MFI), the flow patterns at 40% and 60% moisture content at 40 and 60 mm orifice sizes, respectively, showed funnel flows. although these flow conditions were satisfied to maintain a steady flow. The maximum wall pressure for the funnel flow showed the location of the interlocking phenomenon where the stagnant zone began during discharging. DEM simulation was validated through the mass profiles using the parameters obtained by the experiments. This study demonstrates that the experimental and analytical results with DEM simulation predict the flow behaviors of soybeans well at various moisture contents. These results are useful for designing silos for continuous food processing

The effect of intermittent drying on the cracking ratio of soybeans (Glycine max) at different relative humidity using reaction engineering approach modeling

Intermittent drying (ID) was applied to reduce soybean cracking because of the low moisture gradient and little thermal stress on soybeans during their tempering period. The drying temperature and relative humidity (RH) for the drying and tempering periods were 35°C and 20% and 25°C and 43%, respectively. The intermittency (α) of the drying was defined as the ratio of the drying period to the duration of the drying and tempering periods, and it varied at α = 1, 0.5, 0.4, and 0.25 to evaluate the drying characteristics and the soybeans’ quality. Intermittency processes redistributed the moisture in the soybean so that the low thermal stress was applied to the soybeans. The percentage of cracked grains increased with increasing the duration of drying period and decreasing tempering period. The moisture content and temperature changes during drying of soybeans were well fitted by reaction engineering approach (REA) modeling. Additionally, the physics that describe the soybeans’ drying behavior during ID were explained by the model parameters obtained from the REA modeling, such as the surface relative humidity and the surface water vapor concentration. ID showed the highest drying efficiency at α = 0.25 regarding the total drying time (13,800 s, i.e., the shortest drying time) and the lowest cracking ratio (<2.18%)

Effects of Container Design on the Temperature and Moisture Content Distribution in Pork Patties during Microwave Heating: Experiment and Numerical Simulation

Effects of the container design on the heat transfer rate and food quality during microwave heating were explored and validated with numerical simulations and experiments. The uniformity of moisture content and temperature was investigated, and to describe microwave heating patterns, a simulation model was created. Pork patties with different moisture and salt contents were heated in three different containers (center and edge-perforated lid as well as without lid) to achieve 80 °C using a domestic microwave oven. Compared to the center or mid-way positions, the temperatures at the edge of the patties rose quickly. By containing the evaporated vapor from the heated pork patties inside the container, the container with a center-perforated lid decreased the heating rate and non-uniformity in temperature and moisture content. A simplified numerical model for the electromagnetics, heat, and momentum transfer coupling simulation was developed to understand the moisture and temperature distribution of the pork patties after microwave heating. Heating uniformity and the final quality of the pork patties could be improved by a container with a center-perforated lid. The proposed model was able to describe the microwave warming process for ready-to-eat products; thus, it is a useful tool for designing microwavable ready meals

Effect of moisture uptake on the texture of dried laver Porphyra. (Nori) studied by mechanical characterization and NMR measurement

Mechanical property measurements, 1H T2 measurement by low-field (LF) NMR and 13C T1 measurement by high-resolution cross polarization/magic angle spinning (CP/MAS) solid-state NMR were carried out to evaluate the structural changes of Nori upon moisture uptake.The texture of dry Nori changed to be tough and then soft upon moisture uptake. The increase of 1H T2 and decrease of 13C T1 were observed with an increase of moisture content indicating the increase of the molecular mobility of Nori components.The results of the LF-NMR suggested that the increase of mobility of the inert protons in rigid components is more dominated than that of the labile protons in soft components when Nori becomes the soggy state, whereas the mobility of the soft part increases more by moisture uptake when Nori becomes the wet state. The changes of molecular mobility of each main component (proteins and porphyran) were well depicted by the 13C T1 measurement, which represented the hydration of porphyran and proteins in the pulps and binder part.The change of mechanical properties of Nori was successfully elucidated with the NMR relaxation measurements.公開日: 2022-10-0

Effects of Potato Protein Isolated Using Ethanol on the Gelation and Anti-Proteolytic Properties in Pacific Whiting Surimi

Pacific whiting is a primary species utilized for surimi processing in the Pacific Northwest of the US. However, endogenous protease in Pacific whiting surimi deteriorates the quality during slow cooking. The demand for clean-labeled and economically competitive protease inhibitors has been increasing. In the present study, the anti-proteolytic effect of potato protein isolate (PPI), a by-product from the potato starch industry, prepared using 20% ethanol on the endogenous protease activity of Pacific whiting (PW) surimi was investigated. The ohmic heating method was carried out for a better assessment of the anti-proteolytic activity of inhibitors. A factorial design was carried out in which the independent variables were the four types of inhibitors and their concentration (0, 0.5, 1, 2, and 3% w/w) at two heating conditions. The heating condition was used as a blocking factor. All experiments were randomized within each block. The addition of 2% PPI which demonstrated the highest anti-proteolytic activity among five different concentrations significantly increased the breaking force, penetration distance, and water retention ability of PW surimi gel as the endogenous proteases were effectively inhibited when heated ohmically at 60 °C for 30 min prior to heating up to 90 °C. In addition, SDS-PAGE disclosed that PPI successfully retained the intensity of myofibrillar heavy chain (MHC) protein of PW surimi gels even under the condition at which proteases could be activated at 60 °C. The whiteness of gels was not negatively affected by the addition of PPI. Comparing all samples, a denser and more ordered microstructure was obtained when PPI was added. A similar trend was found from the fractal dimension (Df) of the PPI-added gel’s microstructure. Therefore, PPI could be an effective and non-allergenic protease inhibitor in PW surimi leading to retaining the integrity of high gel quality

Evaluating the Mechanical Response of Agarose-Xanthan Mixture Gels Using Tensile Testing, Numerical Simulation, and a Large Amplitude Oscillatory Shear (LAOS) Approach

Large deformation stress response characteristics of hydrocolloid mixture gel systems were investigated based on texture and rheological measurements. Agarose and xanthan mixtures at different ratios (1:0, 0.75:0.25, and 0.5:0.5) were chosen as the model systems. A decrease in failure stress from 2.65 to 1.82 MPa and an increase in failure strain from 0.08 to 0.13 with higher xanthan ratios were obtained based on the ring tensile test, indicating that xanthan molecules could improve the flexibility of the agarose network. The gels showed severe water loss by compression, particularly for the pure agarose gel (6.74%). Compared to the compression test, the gels presented low water loss after the ring tensile test (<1.3%) indicating that the ring tensile test could calculate the correct stress–strain relationship. Digital image correlation (DIC) and numerical simulation revealed that agarose-xanthan gel systems possess a deformation behavior with homogeneous strain distribution before failure. Elastic and viscous Lissajous–Bowditch curves from the large amplitude oscillatory shear (LAOS) measurement at different strains and frequencies elucidated that the agarose-xanthan gel was dominated by the agarose structure with a similar magnitude of elasticity at a low frequency. The large deformation approach from this study has great potential for elucidating and understanding the structure of food and biopolymer gels

Using Numerical Analysis to Develop a Retort Process to Enhance Antioxidant Activity and Physicochemical Properties of White Radish (Raphanus sativus L.) in Different-Sized Packages

Thermal processing of white radish using retort sterilization at different temperatures was investigated according to the dimension of the package. Four different samples with the same weight and volume were placed in packages with different dimensions. The degree of sterilization (i.e., F0-value) at the cold point targeted at 6 min was determined based on experimental data and heat transfer simulation. The sterilization time was considerably increased with a decrease in surface area to unit volume ratio (φ) at each temperature. The sterilization time for the sample with the highest φ (155.56) was approximately five times faster than the sample with the lowest φ (72.22) at all heating temperatures. Numerical simulation conducted with a proper heat transfer coefficient (h) showed mostly good agreement with the experimental data (RMSE < 2 °C). Changes in color and total phenolic content were higher for samples heated at higher temperatures. Hardness values of white radish samples measured for center and edge parts separately were more uniform for samples with a high φ. Results in this study suggest that optimizing heating conditions of root vegetables must consider their package dimensions to satisfy quality attributes after sterilization. Numerical simulation can be utilized as a useful tool to design the sterilization process

Stress and Strain Characteristics under the Large Deformation of Surimi Gel during Penetration and Extension Tests Using Digital Image Correlation and the Numerical Simulation Method

The stress and strain properties of surimi gels (72.49% moisture content) under large deformation were analyzed during penetration (cylindrical, conical, and spherical puncture) and extension (ring tensile) tests. Mechanical measurements were compared and validated using digital image correlation (DIC) and numerical simulations. The DIC and the finite element method reflected the influence of the probe shape and the surface area in contact with the gel during the measurements. In puncture tests, a larger probe surface increased the strain concentration at the puncture point. In the extension test, the strain distribution was symmetrical. The strain values observed during penetration tests were comparable in both the DIC and numerical simulation. The tensile failure characteristics observed in DIC and numerical simulations are similar to those found in the experiment. The study demonstrated that the extension method with the ring tensile device did not show a stress concentration during the measurement, and DIC and numerical simulation can be effective tools in analyzing the textural properties of surimi gel during the puncture and ring tensile tests

Effect of Moisture Content on the Grinding Process and Powder Properties in Food: A Review

Grinding is a staple size-reduction process to produce food powders in which the powdered form is chemically and microbiologically stable and convenient to use as end products or intermediate products. The moisture content of food materials before grinding is a particularly important factor, since it determines the materials’ physical properties and the powder properties, such as flowability after grinding. Generally, the moisture content of food materials is closely related to its energy requirement for grinding, because the energy expenditure required to create new surfaces varies. Grinding models used to analyze and predict the grinding characteristics, including energy, have been developed in many studies. The moisture content also influences powder flow properties. The inter-particle liquid bridges among the particles are due to the moisture in powders; therefore, the flowability of powders is interrupted because of the increase of the cohesiveness of the powder. Understanding the grinding characteristics related to various moisture contents is, theoretically and experimentally, an important cornerstone in optimizing the grinding processes used in food industries. In this review, comprehensive research of the effect of moisture content on the grinding process and powder properties is presented