Deactivation Method Research Articles

Paper‐Based RNase Digestion toward Viral Nucleic Acid Self‐Tests

AbstractHome‐based Nucleic Acid Amplification Tests (NAATs) for viral infections would be an important step to improve public health, but sample preparation remains an important obstacle, particularly for the protection of target RNA from RNases in samples. Here, a new method for RNase deactivation in saliva samples is presented. This method uses Proteinase K (PK) immobilized on nitrocellulose membrane to store and deliver the enzyme, capable of digesting nucleases present in the sample. The immobilized PK is also separated from the amplification reagents, so that it does not disrupt DNA amplification, thus omitting the need for heat‐deactivation or dilution steps. Treatment by PK nitrocellulose at 50 °C dramatically decreases the RNase activity of RNase A, in diluted saliva samples, and even shows promising results at 42 °C. The potential of this method to protect RNA from digestion is further demonstrated, by pretreating diluted saliva samples spiked with Influenza Virus A (IVA) genomic RNA, which allows its amplification and colorimetric detection by lateral flow strips. In the absence of PK pretreatment, the RNA is digested by RNase, which leads to false negative results. These findings show that immobilized PK enables the integration of sample preparation of viral samples toward home‐based NAATs.

Battery Deactivation for Safe and Efficient Recycling

With the substantial increase in the demand for lithium-ion batteries (LIBs) for the adoption of electrification to reduce CO2 emission, safe and efficient recycling of spent LIBs is essential to utilize LIBs sustainably1. In hydrometallurgy-based or direct LIB recycling systems, which are expected to become mainstream in the future because of their low environmental impacts, deactivation is a crucial pretreatment step to safely handle LIBs during the processes2, 3. However, a common deactivation method, in which an external short circuit is induced using electronic loads or conductive liquid, cannot deactivate LIBs with disconnected electrical circuits or metallic Li plating on the negative electrode surface, despite their high safety risks.We propose the advanced deactivation method, injecting a redox mediator (RM) solution inside the LIBs. The RM delivers electrons from the negative electrode to the positive electrode by cycling the reduction and oxidation on the negative and positive electrodes, respectively (redox shuttle reaction), resulting in discharging LIBs. In other words, the RM causes a short circuit inside the LIB. Therefore, it is possible to discharge a LIB that cannot be discharged externally, for example, a LIB with disconnected electrical circuits due to a safety device operation. Furthermore, the RM can strip Li metal plated on the negative electrode even though it is “dead lithium.” This unique characteristic contributes to the improvement in the safety and the Li collection rate in the recycling processes. Additionally, in this presentation, the deactivation mechanism of LIBs and its relationship with the electrochemical properties of the RMs will be discussed. The present findings will be beneficial and helpful for designing RMs for deactivation of more and more diversified spent LIBs. References J. Neumann, et al.: "Recycling of Lithium‐Ion Batteries—Current State of the Art, Circular Economy, and Next Generation Recycling" Adv. Energy Mater. 12, (2022). A. Kwade, et al.: "Recycling of lithium-ion batteries" The LithoRec Way, Switzerland: Springler International Publishing AG (2018). H. Rouhi, et al.: "Voltage behavior in lithium-ion batteries after electrochemical discharge and its implications on the safety of recycling processes" Journal of Energy Storage 35, (2021).

A quanta-independent approach for the assessment of strategies to reduce the risk of airborne infection

The Wells-Riley model is extensively used for retrospective and prospective modelling of the risk of airborne transmission of infection in indoor spaces. It is also used when examining the efficacy of various removal and deactivation methods for airborne infectious aerosols in the indoor environment, which is crucial when selecting the most effective infection control technologies. The problem is that the large variation in viral load between individuals makes the Wells-Riley model output very sensitive to the input parameters and may yield a flawed prediction of risk. The absolute infection risk estimated with this model can range from nearly 0 % to 100 % depending on the viral load, even when all other factors, such as removal mechanisms and room geometry, remain unchanged. We therefore propose a novel method that removes this sensitivity to viral load. We define a quanta-independent maximum absolute before-after difference in infection risk that is independent of quanta factors like viral load, physical activity, or the dose-response relationships. The input data needed for a non-steady-state calculation are just the removal rates, room volume, and occupancy duration. Under steady-state conditions the approach provides an elegant solution that is only dependent on removal mechanisms before and after applying infection control measures. We applied this method to compare the impact of relative humidity, ventilation rate and its effectiveness, filtering efficiency, and the use of ultraviolet germicidal irradiation on the infection risk. The results demonstrate that the method provides a comprehensive understanding of the impact of infection control strategies on the risk of airborne infection, enabling rational decisions to be made regarding the most effective strategies in a specific context. The proposed method thus provides a practical tool for mitigation of airborne infection risk.

The structure of deposited coke on hydrocracking and reforming catalysts: Coke deactivation and kinetics

AbstractThis comprehensive study investigates the structural deposition of coke, particularly its association with sulphides, in spent hydrocracking and reforming catalysts, leveraging advanced kinetic modelling and characterization techniques. Its objective is to elucidate coke removal kinetics, offering insights into optimizing catalyst regeneration. Utilizing thermogravimetric analysis, spectroscopic methods, and modelling, the research outlines the characteristics and kinetic behaviour of coke during regeneration. The novelty aspect of this study is the use of a reaction‐based model for accurate kinetic analysis and identifying optimal conditions for coke removal. The study recognized both hydrogen‐deficient and hydrogen‐rich amorphous coke, alongside graphitic coke spent catalysts. Thermogravimetric analysis revealed that coke constitutes ~23.8% and 4.6% of the total weight in hydrocracking and reforming catalysts, respectively. The traditional model‐free method for deactivation was found inadequate in predicting coke in the spent reforming catalyst, likely due to the presence of low‐temperature hydrocarbons of soft coke within the catalyst pores. In contrast, a reaction model‐based deactivation approach yielded more consistent evaluations for soft and hard coke of spent catalyst. For the spent hydrocracking catalyst, the estimated activation energies for coke decomposition were 41.56 and 128.97 kJ/mol for soft and hard coke, respectively, during regeneration. Although the coke in the spent reforming catalyst displayed similar temperature trends for decomposition, the average activation energies were 52.61 and 128.62 kJ/mol for soft and hard coke, respectively. The theoretical results from the multi‐reaction model for coke decomposition are consistent with the experimental results for both catalysts.

An Efficient Early-breaking-estimation and Tree-splitting Missing RFID Tag Identification Protocol

Retailers grapple with inventory losses primarily due to missing items, prompting the need for efficient missing tag identification methods in large-scale RFID systems. Among them, few works considered the effect of unexpected unknown tags on the missing tag identification process. With the presence of unknown tags, some missing tags may be falsely identified as present. Thus, the system’s reliability is hardly guaranteed. To resolve these challenges, we propose an efficient early-breaking-estimation and tree-splitting-based missing tag identification (ETMTI) protocol for large-scale RFID systems. ETMTI employs innovative early-breaking-estimation and deactivation methods to swiftly handle unknown tags. Subsequently, a tree-splitting-based missing tag identification method is proposed, employing a B-ary splitting tree, to rapidly identify missing tags. Additionally, a bit-tracking response strategy is implemented to reduce processing time. Theoretical analysis is conducted to determine optimal parameters for ETMTI. Simulation results illustrate that our proposed ETMTI protocol significantly outperforms benchmark methods, offering a shorter processing time and a lower false negative rate.

Cover Image

AbstractThe image emphasizes the innovative strategy of the trap freezing deactivation (TFD) method, as well as numerous applications of the device in X‐ray detection, in the region of medical imaging, security check, scientific research, and space exploration. It also includes popular West Lake views, such as “Remnant Snow on the Broken Bridge” and “Three Ponds Mirroring the Moon”, representing the beauty of nature integrated with science.The inspiration for the design originates from a renowned Chinese painting, which depicts the life of the ancient and modern scholar who resided by the West Lake in Hangzhou. They both immersed themselves in beloved passions in the plum blossom and perovskite, while embracing a hopeful and imaginative outlook towards the future. When the past and present converge, they are in perfect harmony. image

Food Allergens: When Friends Become Foes-Caveats and Opportunities for Oral Immunotherapy Based on Deactivation Methods.

Food allergies represent a serious health concern and, since the 1990s, they have risen gradually in high-income countries. Unfortunately, the problem is complex because genetic, epigenetic, and environmental factors may be collectively involved. Prevention and diagnoses have not yet evolved into efficacious therapies. Identification and control of allergens present in edible substances hold promise for multi-purpose biomedical approaches, including oral immunotherapy. This review highlights recent studies and methods to modify the otherwise innocuous native proteins in most subjects, and how oral treatments targeting immune responses could help cancel out the potential risks in hypersensitive individuals, especially children. We have focused on some physical methods that can easily be conducted, along with chemo-enzymatic modifications of allergens by means of peptides and phytochemicals in particular. The latter, accessible from naturally-occurring substances, provide an added value to hypoallergenic matrices employing vegetal wastes, a point where food chemistry meets sustainable goals as well.

Comparison of Two Lab Simulation Methods of Multiple Heavy Metal Contamination on FCC Catalysts

Qualitative and quantitative description are key to solving the problem of heavy metal contamination on fluid catalytic cracking (FCC) catalysts. The loading efficiencies for different metals were compared for the two lab simulation methods of Multi-Cyclic Deactivation (MCD) and Advanced Catalyst Evaluation (ACE), and the microcatalytic performance of metal-contaminated catalysts was evaluated using an ACE Model C device. The results show that the MCD and ACE methods both obtain extremely high data accuracy, indicating that they can be used to ensure the parallel reliability of experimental results. The typical operating parameters for hydrothermal aging and metals loading can be adjusted to suit different metal types and content targets for either of these two simulation methods. Compared with an equilibrium catalyst from an industrial unit, the MCD method has the advantages of basic hydrothermal aging treatment with less metal loading efficiency, while the ACE method has an accurate metal amount and high loading efficiency for metal contamination, with a metal balance recovery rate above 99.5% at similar activation to the equilibrium catalyst. When used with a reasonable and effective metal pretreatment scheme, these two laboratory simulation methods can be used to evaluate new commercial catalysts and in fundamental experiments for the improvement of FCC catalysts for removal of metal contamination.

Effects of enzyme deactivation conditions on the structure, bound phenol content and antioxidant property of phenol modified Tartary buckwheat protein hydrolysate

In this study, the effects of different enzyme deactivation methods (80, 100, 4 °C and pH 6.0) on the structural characteristics, bound polyphenol content and antioxidant activity of buckwheat protein hydrolyzate-phenol complex (BHP) were investigated. Alcalase was selected for enzymolysis. Amino acid analysis showed that glutamic acid was the most important amino acid in hydrolysate. Molecular weight distribution analysis showed that the hydrolysis can be completed at 3 h. After enzyme deactivation treatment, all hydrolysates were dialyzed to remove aggregates/enzymes (15 kDa). Fourier transform infrared spectroscopy (FTIR) analysis revealed that the characteristic peaks of BHP shifted after treatment. The fluorescence spectra and surface hydrophobicity (Ho) showed that the corresponding values of BHP increased significantly when deactivated at 80 °C and pH 6.0, decreased at 100 °C and remained no change at 4 °C. The content of total bound polyphenol increased when treated at 80 and 4 °C, and decreased at 100 °C and pH 6.0. Meanwhile, the results showed that all BHP have high antioxidant capacity. This work can provide more support for the systematic evaluation of enzyme deactivation methods containing phenolic hydrolysates.

Evaluation of a clinical method for selective electrode deactivation in cochlear implant programming.

Cochlear implants are a neural prosthesis used to restore the perception of hearing in individuals with severe-to-profound hearing loss by stimulating the auditory nerve with electrical current through a surgically implanted electrode array. The integrity of the interface between the implanted electrode array and the auditory nerve contributes to the variability in outcomes experienced by cochlear implant users. Strategies to identify and eliminate poorly encoding electrodes have been found to be effective in improving outcomes with the device, but application is limited in a clinical setting. The purpose of this study was to evaluate a clinical method used to identify and selectively deactivate cochlear implants (CI) electrodes related to poor electrode-neural interface. Thirteen adult CI users participated in a pitch ranking task to identify indiscriminate electrode pairs. Electrodes associated with indiscriminate pairs were selectively deactivated, creating an individualized experimental program. Speech perception was evaluated in the baseline condition and with the experimental program before and after an acclimation period. Participant preference responses were recorded at each visit. Statistically significant improvements using the experimental program were found in at least one measure of speech perception at the individual level in four out of 13 participants when tested before acclimation. Following an acclimation period, ten out of 13 participants demonstrated statistically significant improvements in at least one measure of speech perception. Statistically significant improvements were found with the experimental program at the group level for both monosyllabic words (p = 0.006) and sentences in noise (p = 0.020). Additionally, ten participants preferred the experimental program prior to the acclimation period and eleven preferred the experimental program following the acclimation period. Results from this study suggest that electrode deactivation may yield improvement in speech perception following an acclimation period. A majority of CI users in our study reported a preference for the experimental program. This method proved to be a suitable clinical strategy for identifying and deactivating poorly encoding electrodes in adult CI users.

Deactivation and Regeneration of Palladium Catalysts for Hydrogenation Debenzylation of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-Hexaazaisowurtzitane (HBIW)

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, also known as CL-20) is an important energetic compound. As one of the representatives of the third generation of energetic materials, it has an excellent performance, providing broad application prospects for the development of new weapons and equipment. The synthesis of CL-20 is usually obtained from 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (HBIW) through two catalytic hydrogenolysis and debenzylation reactions, followed by nitration. The most critical step is the hydrogenolysis debenzyl-acetylation process of HBIW because this process requires a large amount of expensive palladium-based catalyst, and the catalyst is completely deactivated after one use. In response to this problem, there is no suitable solution at present, resulting in the high cost of the entire synthesis process. Therefore, reducing the production cost of CL-20 by increasing the catalyst stability is one of the current research priorities. By using AAS, XRD, XPS, TEM, BET, TG and other characterization techniques, the reasons for catalyst deactivation were explored. Studies have shown that the main reason for catalyst deactivation is that a large number of blockages accumulate in the pores of the catalyst after the reaction, which greatly weakens the transfer of the reactant HBIW, intermediate substances, and product 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADBIW) in the catalyst pores, and the blockage may block the active site of the catalyst. A regeneration treatment method for catalyst deactivation was developed. This method uses chloroform and glacial acetic acid as reagents, which, when combined with stirring and ultrasonic operation, finally restores the activity of the Pd(OH)2/C catalyst. The BET and TG parameters of the regenerated catalyst indicate that catalyst textural and structural properties have greatly recovered, indicating that this treatment method can remove the blockages in the catalyst pores.

DEACTIVATION OF IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS AT DISTANCE FOR THE DIGNITY OF DYING (THE 4D STUDY)

DEACTIVATION OF IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS AT DISTANCE FOR THE DIGNITY OF DYING (THE 4D STUDY)

Dry needling in triceps surae muscles and its influence on pressure pain threshold and lower limb posture in active elderly women: a randomized, blinded controlled clinical trial

Background: Aging leads to the loss of anatomical structures and physiological processes such as postural stability. Poor postural control leads to a shift in the center of gravity, thus overloading the musculature. Muscles overloaded due to postural changes do not show enough muscle contraction, causing the appearance of trigger points (TP). Among the PG deactivation methods, the Dry Needling (DN) has been shown to be a good response method in clinical practice. Objective: To analyze the immediate effect of DN on pressure pain threshold (PPT) of latent trigger points of the sural triceps muscles, in order to verify whether there is improvement in the posture of the lower limbs of active elderly women. Methods: A randomized, controlled and blind clinical trial (patients) was carried out. The sample consisted of physically active elderly women from the community. Divided into two groups: DN Group (DNG) and Control Group (CG). Both groups underwent an initial assessment, treatment (DNG) or sham (CG), and reassessment. The tests were: pressure algometer and biophotogrammetry. Data were analyzed from Normality using the Shapiro-Wilk test. The characterization of the sample was analyzed by multivariate analysis of variance (MANOVA) for comparison between groups. For inter and intragroup analysis, mixed Anova with post hoc Bonferroni was used. The level of significance used was p<0.05. Results: The PPT showed an increase in the intragroup analysis for the right (14.03%) and left (14.92%) sides in the GDN group, as for the intergroup analysis, the results of the reassessment were higher in the DNG group compared to the GC. Regarding the posture of the lower limbs, there was no significant improvement in the intergroup and intragroup analyses. Conclusion: The present study demonstrated that the application of Dry Needling in PG in the sural triceps musculature presents an increase in the pressure pain threshold, however, only one session of the technique application was not enough to present a significant improvement in the posture of the lower limbs. of active elderly women. Search registered on the ReBEC (Brazilian Registry of Clinical Trials) platform under the number RBR-97sqsb.

Экспериментальный анализ элементного состава материалов для изготовления газогенераторов модулей подушек безопасности автомобиля

The airbag is a part of the Supplementary Restraint System; along with the safety belt, it is the most important system that protects the driver and passengers if the vehicle collides with static or moving objects. Certain interrelated studies and measures are required so as to develop scientific, technical, design and technological foundations for producing airbag modules for various vehicle types: for example, determining the range of suitable domestic materials and alloys, as well as the compositions of pyrotechnic gas-generating charges to manufacture gas generators. We experimentally evaluated mechanical properties and elemental composition of materials that gas generator parts consist of, which allowed us to establish their domestic analogues. We determined the elemental chemical composition of pyrotechnic gas-generating charges (main and auxiliary) and the primer igniter charge. We used the following methods in our work: an experimental full-scale airbag module deactivation method for subsequently decomposing gas generators to obtain the necessary sample parts to investigate; a method for determining the microhardness of material samples to subsequently evaluate their ultimate tensile strengths; finally, laser-induced breakdown spectroscopy, X-ray fluorescence spectrometry, X-ray and infrared spectroscopy, ion and liquid chromatography, Raman spectroscopy and nuclear magnetic resonance to determine the elemental composition of materials

Parallel Cloth Simulation Using OpenGL Shading Language

The primary goal of cloth simulation is to express object behavior in a realistic manner and achieve real-time performance by following the fundamental concept of physic. In general, the mass–spring system is applied to real-time cloth simulation with three types of springs. However, hard spring cloth simulation using the mass–spring system requires a small integration time-step in order to use a large stiffness coefficient. Furthermore, to obtain stable behavior, constraint enforcement is used instead of maintenance of the force of each spring. Constraint force computation involves a large sparse linear solving operation. Due to the large computation, we implement a cloth simulation using adaptive constraint activation and deactivation techniques that involve the mass–spring system and constraint enforcement method to prevent excessive elongation of cloth. At the same time, when the length of the spring is stretched or compressed over a defined threshold, adaptive constraint activation and deactivation method deactivates the spring and generate the implicit constraint. Traditional method that uses a serial process of the Central Processing Unit (CPU) to solve the system in every frame cannot handle the complex structure of clothmodel in real-time. Our simulation utilizes the Graphic Processing Unit (GPU) parallel processing with compute shader in OpenGL Shading Language (GLSL) to solve the system effectively. In this paper, we design and implement parallel method for cloth simulation, and experiment on the performance and behavior comparison of the mass–spring system, constraint enforcement, and adaptive constraint activation and deactivation techniques the using GPU-based parallel method.

Development of decontamination and detergents for the nuclear industry

At the enterprises of the radiochemical industry in the world, the task is to clean the technological and research equipment, overalls, and personnel from contamination with radioactive products. This task is especially relevant in case of emergencies, for example, such as an accident at a nuclear power plant in Fukushima, Japan. A review of the deactivation methods currently used is reviewed. It has been shown that the most typical pollutants are mixtures of radionuclides 137Cs, 144Ce, 144Pr, 90Sr, and 239Pu. All these elements are prone to the formation of chelate complexes. Therefore, complexing substances should be an essential component of deactivation solutions that form stable, water-soluble complex compounds with these radionuclides. When creating the recipe, we chose those complexing agents with the most persistent complex compounds with the expected pollutants. For research and testing in real conditions, we have prepared three types of technical detergents of various compositions with the code name MDS for decontaminating various surfaces, equipment, and workwear. The composition of these preparations consists mainly of an optimized mixture of surfactants, complexing agents, corrosion inhibitors, and processing aids. The studies were conducted to evaluate the possibility of using these funds for deactivation of premises, equipment, washing clothes in the Federal Unitary Enterprise "Mayak" and at its branch NIKIET in town Zarechny at Beloyarskyaya Nuclear Power Station in Russia. The effectiveness of deactivation was judged by the amount of residual contamination of the surface of the samples. The deactivating ability of MDS preparations for stainless, carbon steel, and plastic contaminated with β- and α-emitting nuclides was tested. The possibility of using MDS detergents for the deactivation of platinum ampoules stored as radioactive waste was assessed. The possibility of using MDS detergents for the deactivation of fabric materials, including underwear and work clothes, was also evaluated. The tests showed the high efficiency of the developed detergent MDS compared to the existing and currently used deactivation agents.

Distribution of Iron on FCC Catalyst and Its Effect on Catalyst Performance.

The effects of different iron contamination content on the formation of iron nodules and the performance of FCC catalysts have been studied by cyclic deactivation treatment using iron naphthenate. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, and SEM. The catalysts’ performance was evaluated by the Advanced Cracking Evaluation device. It has been found that there will be obvious nodulation on the catalyst when the iron concentration exceeds 7,400 μg/g. With the iron deposition from 53 μg/g to 11,690 μg/g, the crystal structure of zeolite will not be destroyed by iron. The surface area and pore volume of the catalyst decreased significantly; the surface area decreased from 125.3 m2/g to 91.0 m2/g, and the pore volume decreased from 0.21 cm3/g to 0.16 cm3/g. The studies also showed that the increase of iron deposition will lead to the decrease of catalytic reaction efficiency. With the iron deposition from 53 μg/g to 11,690 μg/g, the conversion decreased by 4.83%. Under the same 78 wt.% conversion, bottoms yield and coke yield increased by 2.15% and 1.31%, while gasoline yield and LCO yield decreased by 2.59% and 2.16%, respectively. The real state of the industrial iron contaminated equilibrium catalyst can be mimicked by using the cyclic deactivation method.

Crashed Electric Vehicle Handling and Recommendations—State of the Art in Germany

In the near future, electric powered vehicles will represent a major part of the road traffic. Accordingly, there will be a natural increase of accidents involving electric vehicles. There are not many cases of such accidents yet and therefore the experience and correct handling are still partially open points for the involved parties, such as the rescue services for example. The aim of this work is to provide a complete overview of the accident handling sequence in Germany, starting with the damaged vehicle on site and moving on to the risks and challenges for the stakeholders, such as transport and recycling companies. Arising from the developed overview, a handling recommendation for yet undiscussed points is given. Especially, different extinguishing and deactivation methods are compared and discussed. Due to a lack of a common live-feed from battery data on site, other criteria have to be taken into account to assess the state of the battery. The wrecked vehicle—including the high voltage system—needs to be in a definite safe state at the handover to a towing service. Depending on the case, different options for securing the vehicle will be considered in this work.

A Comparison of Laboratory Simulation Methods of Iron Contamination for FCC Catalysts

Two different methods of simulating iron contamination in a laboratory were studied. The catalysts were characterized using X-ray diffraction, N2 adsorption–desorption, and SEM-EDS. The catalyst performance was evaluated using an advanced cracking evaluation device. It was found that iron was evenly distributed in the catalyst prepared using the Mitchell impregnation method and no obvious iron nodules were found on the surface of the catalyst. Iron on the impregnated catalyst led to a strong dehydrogenation capacity and a slight decrease in the conversion and bottoms selectivity. The studies also showed that iron was mainly in the range of 1–5 μm from the edge of the catalyst prepared using the cycle deactivation method. Iron nodules could be easily observed on the surface of the catalyst. The retention of the surface structure in the alumina-rich areas and the collapse of the surface structure in the silica-rich areas resulted in a continuous nodule morphology, which was similar to the highly iron-contaminated equilibrium catalyst. Iron nodules on the cyclic-deactivated catalyst led to a significant decrease in conversion, an extremely high bottoms yield, and a small increase in the dehydrogenation capacity. The nodules and distribution of iron on the equilibrium catalyst could be better simulated by using the cyclic deactivation method.

Effect of cold and hot enzyme deactivation on the structural and functional properties of rice dreg protein hydrolysates

This study explored the effect of three different enzyme deactivation treatments: 4 °C slow cold deactivation (RDPH-(4 °C)), −18 °C rapid cold deactivation (RDPH-(−18 °C)) and 100 °C water bath (RDPH-(100 °C)), compared to that without enzyme deactivation (RDPH-(control)) on the structural and functional properties of rice dreg protein hydrolysates (RDPHs). The RDPHs from the different enzyme deactivation methods led to significant differences in the degree of hydrolysis, surface hydrophobicity, average particle size, intrinsic fluorescence and emulsion stability. FTIR analysis revealed that the strength of RDPH-(100 °C) spectrum peaks decreased significantly. All samples showed high solubility (>85%) and potent antioxidant capacity: DPPH (~90%), ABTS (~99%), and reducing power (0.86–1.03). Among the hydrolysates evaluated, the RDPH-(100 °C) led to the lowest reducing power and hydroxyl radical scavenging activity. Results reported here will be instrumental for the development of rice protein-based products and in the optimization and scale up of manufacturing process.