The effects of microbial transglutaminase (MTGase) cross-linking on the physicochemical characteristics of individual caseins were investigated. MTGase was used to modify three major individual caseins, namely, κ-casein (κ-CN), α_S-casein (α_S-CN) and β-casein (β-CN). The SDS-PAGE analysis revealed that MTGase-induced cross-linking occurred during the reaction and that some components with high molecular weights (>130 kDa) were formed from the individual proteins κ-CN, α_S-CN and β-CN. Scanning electron microscopy (SEM) and particle size analysis respectively demonstrated that the κ-CN, α_S-CN and β-CN particle diameters and protein microstructures were larger and polymerized after MTGase cross-linking. The polymerized κ-CN (~749.9 nm) was smaller than that of β-CN (~7909.3 nm) and α_S-CN (~7909.3 nm). The enzyme kinetics results showed K_M values of 3.04 × 10⁻⁶, 2.37 × 10⁻⁴ and 8.90 × 10⁻³ M for κ-CN, α_S-CN and β-CN, respectively, and, furthermore, k_cat values of 5.17 × 10⁻⁴, 1.92 × 10⁻³ and 4.76 × 10⁻² 1/s, for κ-CN, α_S-CN and β-CN, respectively. Our results revealed that the cross-linking of β-CN catalyzed by MTGase was faster than that of α_S-CN or κ-CN. Overall, the polymers that formed in the individual caseins in the presence of MTGase presented a higher molecular weight and larger particles.

A heat and mass-transfer model coupled with reaction kinetics was developed to simulate frying. Obtaining an accurate mathematical model of the Maillard reaction and the heat and mass transfer is crucial for predicting the transient acrylamide formation, temperature, and water content in French fries. The objective of this study was to mitigate the formation of acrylamide in a potato strip by adopting a temperature step frying approach (TSFA). A considerable increase in the water content and a decrease in the temperature and acrylamide formation were observed in a potato strip fried with the TSFA compared with a potato strip fried without the TSFA process. The acrylamide content in a potato strip when fried using the TSFA decreased considerably to 57% of that in a potato strip fried without using the TSFA. Simulation of the acrylamide distribution in a potato strip revealed that the crust contains the highest amount of acrylamide. The proposed model can be successfully used to obtain high-quality products, mitigate acrylamide formation, and save energy.

The working principle of enzyme-based biofuel cells (EBFCs) is the same as that of conventional fuel cells. In an EBFC system, the electricity-production process is very intricate. Analysis requires a mathematical model that can adequately describe the EBFC and predict its performance. This paper develops a dynamic model simulating the discharge performance of the anode for which supported glucose oxidase and mediator immobilize in the EBFC. The dynamic transport behavior of substrate, redox state (ROS) of enzyme, enzyme-substrate complex, and the mediator creates different potential changes inside the anode. The potential-step method illustrates the dynamic phenomena of substrate diffusion, ROS of enzyme, production of enzyme-substrate complex, and reduction of the mediator with different potential changes.

The aim of this research was to investigate the effects of the addition of 0.5% hydroxymethylfurfural (HMF) and low molecular chitosan on acrylamide and HMF formation in a food model system, which contains 0.5% glucose, asparagine, and HMF within 30 min of heating at 180 °C. At an interval of 10 min, all solutions were evaluated in the following aspects: reducing sugar, asparagine, acrylamide, HMF content, pH, Maillard reaction products, kinematic viscosity, and color. After heating for 10 min, the kinematic viscosity of solutions containing chitosan reduced significantly. The values of the acrylamide, HMF, and absorbance increased at OD₂₉₄ and OD₄₂₀ (optical density measured at 294 nm and 420 nm) of solutions. Experimental results showed that low-molecular-weight chitosan might be hydrolyzed into much lower molecular weight, followed by the decrease in kinematic viscosity of the solution at pH lower than 6 and the increase in the formation of acrylamide after heating for 30 min.

The development of an effective drying performance of the fluidized bed dryer (FBD) is crucial to reduce drying costs. The objective of this study was to investigate the drying performance of wheat germ (WG) with different time-temperature combinations in the FBD. The WG was dried at different set temperatures of 80, 100 and 120 °C. The moisture content (MC) and water activity (WA) of WG were measured. A mathematical model was proposed to develop an optimal drying condition. The changes in the MC of WG during drying in the FBD could be divided into the decreased period, the dynamic equilibrium period and the increased period. The product temperature of 45 °C and WA of 0.3 of WG drying could be attained by different time-temperature combinations. The mathematical model, which was developed in conjunction with different time-temperature combinations, could predict the dehydration time and the condensation time of WG for optimization the drying conditions. The WG dehydration at the heating stage and the WG condensation at the cooling stage could also be evaluated by the dehydration flux and the condensation flux, respectively. The optimal drying performance of WG exists in a compromise between promoting dehydration and reducing condensation. Information obtained from the analysis of dehydration flux and condensation flux with experimental data and simulation gave the guidelines for performing an effective drying of WG in the FBD.

The fat content of fried pork rinds is high, and alternative frying helps reduce the oil content and maintain their texture and taste. Different frying methods such as microwave-assisted, traditional deep frying and vacuum frying on the breaking force, color, microstructure, water loss and oil absorption attributes of fried pork rinds were evaluated in this study. The fat content of microwave-assisted and vacuum-fried pork rinds was lower (24.2 g/100 g dry weight basis (db) and 17.1 g/100 g db, respectively) than that (35.6 g/100 g db) of traditional deep-fat frying. Non-uniform, holy and irregular surface microstructures were obtained by vacuum frying due to rapid mass transfer at low pressure. The first-order kinetic models of water loss and oil absorption of traditional and microwave-assisted frying of pork rinds were established. Microwave frying caused a faster moisture loss rate, shorter frying time and lower pork rind oil content, makes it an attractive substitute for traditional deep-fat frying.