Repeated freeze-thaw (FT) cycles deteriorate the quality of frozen dough by disrupting the structural integrity of gluten and starch macromolecules. This study systematically investigated the effects of preheating temperatures (45 degrees C-65 degrees C) and FT cycles (0-8) on the quality and macromolecular characteristics of non-fermented dough to identify the optimal temperature window and elucidate the underlying mechanisms. The results demonstrated that while all doughs exhibited a degradation in textural and rheological properties with increasing FT cycles, a distinct temperature-dependent effect was evident. Preheating at 50 degrees C-55 degrees C proved more effective in mitigating dough degradation, outperforming treatment at 45 degrees C, whereas treatments at 60 degrees C and 65 degrees C resulted in significant quality loss. The enhancement mechanism was primarily attributed to the optimal preheating (50 degrees C-55 degrees C), which reinforced the gluten network by promoting disulfide bond formation, evidenced at the initial state (FT-0) by increased glutenin macropolymer (GMP) content and decreased free sulfhydryl (-SH) levels compared to the control. This reinforced matrix restricted water mobility and physically hindered starch recrystallization during FT cycles. This research elucidates the temperature-dependent mechanism by which moderate thermal pretreatment enhances the FT stability of non-fermented dough, establishing a clear structurefunction relationship for gluten and starch macromolecules. Moreover, it provides a scientific basis for innovative strategies aimed at improving frozen dough quality and facilitating the development of new frozen flour products.

Frozen dough technology faces two major challenges: loss of yeast viability caused by freezing damage, and uncontrolled fermentation due to delayed freezing or temperature rise during thawing. In this study, a thermo-responsive double-layered microcapsule based on shellac and hydroxypropyl methylcellulose (HPMC) was developed to achieve cryoprotection and controlled release of yeast. Active dry yeast was encapsulated with HPMC (30 mPa·s) via a wet powder-layering method (loading capacity: 76.15%; survival after subsequent ethanol exposure: 93.25%). The outer shellac layer was plasticized with tributyl citrate (TBC), where 7.5% TBC was identified as the optimal concentration. Dynamic mechanical analysis (DMA) showed that the formulation with 7.5% TBC maintained relatively high rigidity at frozen storage temperatures. In contrast, it underwent significant softening within the proofing temperature range (35-40 °C). Dynamic vapor sorption (DVS) results showed that this group exhibited the lowest moisture absorption rate at 25 °C and enhanced moisture absorption response at 40 °C. Optical microscopy and spectrophotometric turbidity analysis verified that the rehydration of HPMC-yeast cores generated substantial volumetric expansion and internal swelling stress, triggering a temperature-dependent ductile shell deformation and rupture in the 7.5% TBC group, which was superior to the brittle fracture of the 0% TBC group. In frozen dough applications, the microcapsules effectively suppressed premature fermentation during cold holding, realized a controlled "delayed activation-concentrated fermentation" behavior, and preserved yeast survival at 86.47% after 6 freeze-thaw cycles (compared to 59.48% in the unencapsulated control). This encapsulation strategy provides a high-performance solution for stable, controllable frozen fermented products.

Iron yam (Dioscorea opposita Thunb.) is widely valued as a medicinal and food resource but is highly susceptible to enzymatic browning due to its abundant polyphenol oxidase (PPO), which severely degrades its processing quality. To address these issues, this study developed a novel simultaneous blanching system and systematically compared the effects of radio frequency blanching (RF), 100 degrees C saturated steam blanching (SS), 110 degrees C superheated steam blanching (SSB), and RF combined with steam blanching (RF + SS and RF + SSB) on PPO inactivation, heating uniformity, physicochemical properties, and microstructure of iron yams. The heating uniformity indices (lambda) values of RF + SS (0.058-0.068) and RF + SSB (0.055-0.062) were significantly lower than other treatments (P < 0.05), indicating more uniform temperature distribution. Under the same PPO inactivation conditions, the RF + SSB group had shorter processing time (45 s), better color (Delta E = 3.26 +/- 0.62) texture, Vitamin C (82.50 +/- 1.64 %) retention of yam, and a lower relative electrolyte leakage (REL) (63.1 %). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations further revealed that RF + SSB caused minimal cell disruption. RF combined with steam blanching is an innovative and promising blanching method to enhance the enzyme inactivation efficiency and quality of fruits and vegetables, which is important for fruit and vegetable processing.

The sodium alginate (SA) edible coating containing cinnamon essential oil microcapsules (CEOM) was produced to extend the shelf life of fresh chicken breast. The microcapsules, with a core/wall ratio of 1:4, achieved a maximum encapsulation efficiency of 72.21% and an average particle size of 4.73 mu m. Hydrogen bonding was identified as the primary interaction between cinnamon essential oil (CEO) and gum Arabic. CEOM demonstrated excellent storage stability at 4 degrees C for 7 days and exhibited strong antibacterial activity against Escherichia coli and Staphyloccocus aureus, with minimum inhibitory concentrations of 10.000 and 5.000 mg/mL, respectively. Incorporating CEOM into SA coatings could reduce weight loss, pH changes, total viable counts, and total volatile base nitrogen levels. The SA-CEOM-3.0 coating extended the shelf life of chicken breasts to 3 days, maintaining desirable texture, odour, and overall acceptability. These findings reveal that SA-CEOM coatings are a promising antibacterial solution for meat preservation.

Peanuts continue to be processed using traditional, time-intensive methods, such as frying. This study explored microwave or radio frequency preheating combined with oven roasting to reduce processing time while maintaining product quality. Compared with dry-fried peanut kernel (DFPK) samples that take 18 min to reach 90 °C, microwave-preheated and oven-roasted peanut kernel (MWPK) samples reached 130 °C in 70 s, and radio frequency-preheated and oven-roasted peanut kernel (RFPK) samples reached 130 °C in 180 s. Sensory evaluation was used to optimize oven roasting conditions, with MWPK samples receiving higher scores than RFPK and DFPK samples. Volatile compound analysis, which was conducted using headspace solid-phase microextraction-gas chromatography-mass spectrometry, revealed 2,5-dimethyl-pyrazine and 2-ethyl-3-methyl-pyrazine as the primary aromatic compounds generated during the Maillard reaction. The optimal process involved 70 s of microwave preheating followed by oven roasting at 130 °C for 5 min. Overall, this process yielded high-quality peanut kernels while reducing processing time and energy consumption.

Stewed goat meat is a common dish in northwestern China, but research on how spices synergistic effects influence its flavor is limited. This study investigated the effects of five Chinese traditional spices (peppercorn, ginger, dried chili, thyme, red onion) on stewed goat meat flavor. The results showed that free amino acids content in peppercorn, ginger, and thyme groups decreased to 77.66 %, 81.85 % and 84.82 %, respectively, compared to the spiceless group. The spices combination (GT group) demonstrated synergistic effects, increasing the equivalent umami concentration in meat to 0.13 g MSG/100 g while suppressing sourness and bitterness. Volatile analysis identified 80 compounds in the GT group, enriched with terpenes. Furthermore, the GT group significantly inhibited lipid oxidation, yielding the highest total free fatty acids content (251.08 mg/100 g). This study provided a strong theoretical foundation for further improving the flavor of stewed goat meat, satisfying consumer demands for high-quality food.

This study elucidated the mechanism through which radio frequency explosion puffing (RFEP) improved the texture of purple sweet potato chips by inducing multiscale structural changes. Higher energy inputs and pressures resulted in higher crispness, porosity, acceptability, and lower bulk density. RFEP disrupted hydrogen bonding, hydrophobic interactions, and ionic bonding within the flour, resulting in partial separation of starch and protein. This process decreased the short-range ordering and the LF-β-sheet and β-turn contents, despite the primary structure of proteins remaining intact. These changes led to a looser flour structure and a decrease in storage modulus. Notably, storage modulus, short-range ordering, LF-β-sheet, and β-turn parameters were significantly negatively correlated with crispness and porosity and positively correlated with bulk density. Taking the processing costs into account, the optimum puffing conditions were determined as a pressure of 0.2 MPa, a puffing temperature of 90 οC and a holding time of 0 min.

High internal phase emulsions (HIPEs) enriched with carotenoids were prepared using one-step shearing method, with the assistance of sodium casein(SC)-sucrose esters(SE), to further improve the stability of natural carotenoids. We investigated the properties of HIPEs with diverse SC-SE concentrations and ratios. Results indicated that the combination of SC-SE concentrations at 10 % and 12.5 % and ratios at 1:1 and 2:1 shows significant improvements in HIPEs stability. Notably, the stable network structure was formed in the HIPEs system by increasing electrostatic interactions and hydrogen bonds between SC and SE. Observations using Cryo-SEM further showed that the oil droplets in HIPEs were spaced apart by a dense three-dimensional mesh structure, and uniform filamentous protrusions were formed on the surface of oil droplets. HIPEs exhibited ideal cold storage and heat resistance, and the retention rates of zeaxanthetin dipalmitate (ZDP) were 95.48 % and 78.60 % respectively, after being heated at 100 degrees C for 3 cycles and exposed to ultraviolet light at 4 degrees C for 28 days. In vitro digestion results showed ZDP in the system had good slow-release performance. This could provide a new perspective for developing delivery systems for fat-soluble active ingredients requiring slow-release performance or functional foods with satiety.

Radiofrequency explosion puffing (RFEP) effectively improved the texture of original-cut purple sweet potato chips and the characteristics of cell-wall polysaccharides at various energy levels (85, 90 and 95 °C) and puffing pressures (0.1, 0.2 and 0.285 MPa). Increased ratio frequency (RF) energy input and puffing pressure resulted in a larger puffing volume, while also decreasing hardness and the retention rate of anthocyanin. The RF heating and puffing process promoted the partial conversion of Na2CO3-soluble pectin (NSP) into water-soluble pectin (WSP), promoting the de-esterification of WSP and chelate-soluble pectin (CSP). These changes were accompanied by the depolymerization of pectin chains and their side chains, as well as a decrease in molecular weight (Mw), collectively contributing to a looser pectin structure with diminished apparent viscosity. Volume ratio showed a highly significant positive correlation with the WSP content, and the branching density of WSP and NSP. Conversely, hardness and retention rate of anthocyanin showed a strong positive relationship with Mw, the degree of esterification, the linearity of the pectin fractions, and the contribution of the rhamnogalacturonan-I domain the three types of pectin. For optimal processing efficiency and cost-effectiveness, the puffing conditions were determined to be 0.2 MPa and 90 °C.

The effects of sugar boiling pretreatment (SBP) with different maltitol concentrations (20 %, 30 %, and 40 %) and boiling time (0 - 6 min) on the physicochemical and functional properties of purple sweet potato flour and the radiofrequency explosion puffing (RFEP) quality were investigated. The results showed that the volume ratio, crispness, anthocyanin retention rate and overall acceptability of the samples were maximized after boiling for 6 min at 40 % maltitol concentration achieving increases of 78.63 %, 437.50 %, 392.25 % and 552.94 %, respectively compared to the control (p < 0.05). Fourier transform-infrared spectroscopy and X-ray diffraction analyses revealed that the flour underwent hydrogen bond breaking and formed hydrogen bonds with maltitol at high temperatures, forming maltitol starch-protein / lipid complexes, resulting in decreased crystallinity, shortrange ordering, random coil,-helix and enthalpy, while the non-crystalline region area and-sheet increased. Additionally, the viscosity and storage modulus of the flour increased following pregelatinization. Conversely, as maltitol concentration increased, both viscosity and storage modulus decreased, facilitating the expansion of puffing volume due to the instantaneous total drainage of water upon pressure release. Furthermore, SBP effectively preserved the color and anthocyanin content of the chips. These findings may provide valuable insights for regulating oil-free puffing quality of starchy foods.

The effects of radio frequency (RF) and hot water blanching on polyphenol oxidase (PPO) activity, physicochemical properties, and microstructure of iron yams were investigated. The heating rate of RF was the largest, and the heating uniformity was the best at the electrode gap of 160 mm and the material height of 90 mm. The residual activity of PPO was significantly reduced from 49.95% to 4.21%, whereas the RF heating temperature (65-85 degrees C) increased (p < 0.05). The color and texture of yams treated with RF blanching were better preserved compared with those of hot water blanching at a similar degree of enzyme inactivation. The microstructure showed that these changes in physicochemical properties were caused by cellular damage. The surface cells of yams were more severely damaged than the center cells after hot water blanching at 95 degrees C for 3 min. Moreover, the surface cells after hot water blanching also showed more damage than the cells after RF blanching. Thus, RF blanching is a technique with development potential in the food industry.

Due to the lack of corresponding analysis on appropriate mapping operator between two grids, high-order two-grid difference algorithms are rarely studied. In this paper, we firstly discuss the boundedness of a local bi-cubic Lagrange interpolation operator. And then, taking the semilinear parabolic equation as an example, we first construct a variable-step high-order nonlinear difference algorithm using compact difference technique in space and the second-order backward differentiation formula (BDF2) with variable temporal stepsize in time. With the help of discrete orthogonal convolution (DOC) kernels and a cut-off numerical technique, the unique solvability and corresponding error estimates of the high-order nonlinear difference scheme are established under assumptions that the temporal stepsize ratio satisfies rk < 4.8645 and the maximum temporal stepsize satisfies tau = o(h^1/2 ). Then, an efficient two-grid high-order difference algorithm is developed by combining a small-scale variable-step high-order nonlinear difference algorithm on the coarse grid and a large-scale variable-step high-order linearized difference algorithm on the fine grid, in which the constructed piecewise bi-cubic Lagrange interpolation mapping operator is adopted to project the coarse-grid solution to the fine grid. Under the same temporal stepsize ratio restriction rk < 4.8645 and a weaker maximum temporal stepsize condition tau = o(H^1.2 ), optimal fourth-order in space and second-order in time error estimates of the two-grid difference scheme is established if the coarse-fine grid stepsizes satisfy H = O(h^4/7). Finally, several numerical experiments are carried out to demonstrate the effectiveness and efficiency of the proposed scheme.

The effects of radiofrequency (RF) heating on the activity, structure, and surface hydrophobicity of mushroom polyphenol oxidase (PPO) were examined and four kinetic models of inactivation (First-order model, Weibull model, Logistic model and Bi-phasic model) were fitted. The results demonstrated that RF heating could effectively inactivate PPO, logistic and Bi-phasic model attained the best fit. The circular dichroism (CD) and fluorescence spectroscopy spectra revealed that RF heating at 65 degrees C for 180 s caused changes in the secondary and tertiary structures of PPO, reducing the alpha-helix content from 38.5% to 30.3% and red-shifting the emission peak wavelength of the maximum fluorescence intensity from 318 nm to 321 nm. RF heating also caused a significant enhancement of the surface hydrophobicity of the PPO (P < 0.05). The color test results showed that RF heating could inhibit the browning of mushrooms (P < 0.05). Thus, RF heating is an effective technique for the inactivation of enzymes and further research should be performed on RF heating applications to inactivate enzymes in the food industry.

Radio frequency (RF) heating is a novel technology applied to drying and puffing. In the previous study, the optimal conditions for RF drying and puffing of composite purple sweet potato chips were 60% initial moisture content, 1 mm sample thickness, and 110 mm electrode gap. The effects of RF treatment temperature (50-110 degrees C) on the quality, physicochemical properties, and starch structure of composite purple sweet potato chips were further studied in this research. With the increase in RF treatment temperature, the protein, starch, and anthocyanin content in the samples were significantly reduced. However, the reducing sugar content, gelatinization degree, water absorption index (WAI), and water soluble index (WSI) were greatly improved. No new functional groups were produced after RF treatment. The starch changed from A-type to B-type crystal structure at temperature of 65 degrees C, which may result in the formation of a new double helix structure. Moreover, a larger irregular structure was observed at low temperatures of 50-65 degrees C, while this structure disintegrated into debris at high temperatures of 80-110 degrees C. This study provided a theoretical foundation for applying RF drying and puffing technology to starchy foods.

Radio frequency explosion puffing (RFEP) is a novel oil-free puffing technique used to produce crispy textured and nutritious puffed snacks. This study aimed to investigate the effects of freezing at different temperatures (-20 °C, -40 °C, -80 °C) for14 h and freezing times (1 and 2 times) on the cellular structure of purple sweet potato and the quality of RFEP chips. The analysis of cell microstructure, conductivity, and rheology revealed that higher freezing temperatures and more freezing times resulted in increased damage to the cellular structure, leading to greater cell membrane permeability and decreased cell wall stiffness. However, excessive damage to cellular structure caused tissue structure to collapse. Compared with the control group (4 °C), the RFEP sample pre-frozen once at -40 °C had a 47.13 % increase in puffing ratio and a 61.93 % increase in crispness, while hardness decreased by 23.44 % (p < 0.05). There was no significant change in anthocyanin retention or color difference. X-ray microtomography demonstrated that the RFEP sample pre-frozen once at -40 °C exhibited a more homogeneous morphology and uniform pore distribution, resulting in the highest overall acceptability. In conclusion, freezing pre-treatment before RFEP can significantly enhance the puffing quality, making this an effective method for preparing oil-free puffing products for fruits and vegetables.

Radio frequency (RF) heating has been utilized to investigate sterilization techniques, but the mechanism of sterilization via RF heating, particularly on Bacillus cereus (B. cereus), has not been thoroughly examined. In this paper, sterilization processes and potential bactericidal mechanisms of B. cereus using RF were investigated. The best heating and sterilization efficiency was achieved at (Electrode gap 130 mm, conductivity of bacterial suspension 0.1 S/m, volume of bacterial suspension 40 mL). Heating a suspension of B. cereus to 90 °C in 80 s using RF reduced the number of viable bacteria by 4.87 logarithms. At the cellular level, there was a significant leakage of nucleic acids and proteins from the bacterial cells. Additionally, the integrity of the cell membrane was severely damaged, with a decrease in ATP concentration of 2.08 mM, Na, K-ATPase activity to 10.7 (U/109 cells), and Ca, Mg-ATPase activity to 11.6 (U/109 cells). At the molecular level, transcriptomics analysis showed that RF heating of B. cereus to 65 °C produced 650 more differentially expressed genes (DEGs) compared with RF heating to 45 °C. The GO annotation analysis indicated that the majority of differentially expressed genes (DEGs) were predominantly associated with cellular components. KEGG metabolic analysis showed enrichment in microbial metabolism in diverse environments, etc. This study investigated the potential bactericidal mechanism of B. cereus using RF, and provided some theoretical basis for the research of the sterilization of B. cereus.

A new method based on dielectric properties has been developed to distinguish blended soy sauce from fermented soy sauce. Fifty samples of pure fermented soy sauce and blended soy sauce with different contents of hydrolyzed vegetable protein (HVP) were prepared. The dielectric constant and dielectric loss factor of all soy sauce samples in the 30 MHz–3,000MHz frequency range were measured using an impedance analyzer. The sample set was divided into a correction set and a prediction set using the joint x-y distances (SPXY) algorithm, and the partial least squares (PLS) and support vector machine (SVM) models were adopted to distinguish the different samples. The effects of selecting characteristic variables on model prediction using the full spectra (FS), principal component analysis (PCA), and successive projection algorithm (SPA) were compared. Results indicate that the discriminant effect of the PLS model was better than that of the SVM model overall. The SPA–PLS model had the best predictive performance among the six developmental models. The correlation coefficients of the correction set and prediction set were 0.9205 and 0.9096, respectively. The root mean square error of the calibration set was 1.3699 and that of the prediction set was 1.5950. The study demonstrated that the combination of dielectric spectra and stoichiometry can be utilized to determine whether soy sauce has been adulterated.

A large-capacity radio frequency (RF) rotation heating system was employed in this study to heat dried black fungus, and hot air was used for assistance treatment. The effects of electrode gap, rotation rate and hot air on the uniformity of RF heating of dried black fungus were explored. The optimal heating process parameters were obtained, and the sterilization effect was validated. The results showed that the rotation system could significantly enhance the RF heating uniformity of black fungus (P > 0.05). The optimal heating process for heating a large-capacity (480 g) black fungus was to utilize RF heating assisted by 70 C-degrees hot air with an electrode gap of 175 mm and a rotation rate of 60 rpm, followed by 30 min of heat preservation at 70( degrees )C hot air with a rotation rate of 40 rpm. After the entire sterilization treatment, the heating uniformity index lambda of black fungus was reduced to 0.027 +/- 0.004, the total plate count decreased by 3 log CFU/g, and the moisture content dropped to below 13 %. The ideal RF heating uniformity and sterilization effect of black fungus were obtained in this study through the simultaneous use of hot air and rotation, providing a theoretical foundation for the application of RF technology in the processing of black fungus.