Structural, material and antibacterial properties of quercetin incorporated soy protein isolate films and its binding behavior through molecular docking.

This study aimed to investigate the three different methods for the fabrication of quercetin (1%-3% w/w of protein) incorporated soy protein isolate (SPI) films and their effect on material properties. The quercetin incorporated SPI films prepared by these methods were characterized by Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectrophotometer, tensile properties, and water uptake and leaching properties. The cross-linking pattern was revealed by the FTIR spectrum that showed formation of an ester group because of interaction between the quercetin hydroxyl group and the carboxyl side chain of SPI amino acids. The tensile strength of SPI films were enhanced with the addition of quercetin as it increased to a maximum of 6.17 MPa while neat SPI film had tensile strength 4.13 MPa. The prepared films exhibit significant antibacterial activity against Listeria monocytogenes and Escherichia coli. The In-silico docking analysis demonstrates that covalent and non-covalent forces play crucial roles in binding interaction. It shows the formation of four hydrogen bonds, two salt bridges along with one pi-alkyl interaction. The simulation studies reflect the crucial amino acid residues involved in SPI-quercetin binding. The effect of quercetin binding with SPI on its stability and compactness is revealed by Root mean square deviation (RMSD) and radius of gyration studies.

The non-covalent and covalent interactions of whey proteins and saccharides: influencing factor and utilization in food.

During the application of Whey proteins (WPs), they often have complex interactions with saccharides (Ss), another important biopolymer in food substrate. The texture and sensory qualities of foods containing WPs and Ss are largely influenced by the interactions of WPs-Ss. Moreover, the combination of WPs and Ss is possible to produce many excellent functional properties including emulsifying properties and thermal stability. However, the interactions between WPs-Ss are complex and susceptible to some processing conditions. In addition, with different interaction ways, they can be applied in different fields. Therefore, the non-covalent interaction mechanisms between WPs-Ss are firstly summarized in detail, including electrostatic interaction, hydrogen bond, hydrophobic interaction, van der Waals force. Furthermore, the existence modes of WPs-Ss are introduced, including complex coacervates, soluble complexes, segregation, and co-solubility. The covalent interactions of WPs-Ss in food applications are often formed by Maillard reaction (dry or wet heat reaction) and occasionally through enzyme induction. Then, two common influencing factors, pH and temperature, on non-covalent/covalent bonds are introduced. Finally, the applications of WPs-Ss complexes and conjugations in improving WP stability, delivery system, and emulsification are described. This review can improve our understanding of the interactions between WPs-Ss and further promote their wider application.

Discovery of a novel spotted fever group Rickettsia, "Candidatus Rickettsia kedanie," in unfed larval chigger mites, Leptotrombidium scutellare.

Spotted fever group (SFG) rickettsia, the causative agent of SFG rickettsiosis, is predominantly carried by ticks, whereas Orientia tsutusgamushi, the causative agent of scrub typhus, is primarily transmitted by chigger mites in Japan. In this study, we attempted to isolate intracellular eubacteria from Leptotrombidium scutellare, a major vector of O. tsutsugamushi; moreover, we isolated an SFG rickettsia using a mosquito-derived cell line. Draft genome sequences of this unique isolate, by applying criteria for species delimitation, classified this isolate as a novel strain, proposed as "Rickettsia kedanie." Further genetic analysis identified conserved virulence factors, and the isolate successfully propagated in mammalian cells, suggesting its ability to cause diseases in humans. The presence of SFG rickettsia in unfed larvae implies potential dual-pathogen carriage and reflects a symbiotic relationship similar to that between the mites and O. tsutsugamushi, indicating possibility of its transovarial transmission from female adults. Furthermore, conserved genomic similarity of the novel isolate to known SFG rickettsia suggests potential multiple hosts, including chiggers and ticks. In the natural environment, ticks, chigger mites, and wild animals may carry new isolates, complicating the infection cycle and increasing the transmission risks to humans. This discovery challenges the conventional association of SFG rickettsia with ticks, emphasizing its implications for research and disease control. However, this study was confined to a particular species of chigger mites and geographic area, underscoring the necessity for additional studies to comprehend the ecological dynamics, host interactions, and health implications linked to this newly identified SFG rickettsia.

Genome-Resolved Metagenomics and Denitrifying Strain Isolation Reveal New Insights into Microbial Denitrification in the Deep Vadose Zone.

The heavy use of nitrogen fertilizer in intensive agricultural areas often leads to nitrate accumulation in subsurface soil and nitrate contamination in groundwater, which poses a serious risk to public health. Denitrifying microorganisms in the subsoil convert nitrate to gaseous forms of nitrogen, thereby mitigating the leaching of nitrate into groundwater. Here, we investigated denitrifying microorganisms in the deep vadose zone of a typical intensive agricultural area in China through microcosm enrichment, genome-resolved metagenomic analysis, and denitrifying bacteria isolation. A total of 1000 metagenome-assembled genomes (MAGs) were reconstructed, resulting in 98 high-quality, dereplicated MAGs that contained denitrification genes. Among them, 32 MAGs could not be taxonomically classified at the genus or species level, indicating that a broader spectrum of taxonomic groups is involved in subsoil denitrification than previously recognized. A denitrifier isolate library was constructed by using a strategy combining high-throughput and conventional cultivation techniques. Assessment of the denitrification characteristics of both the MAGs and isolates demonstrated the dominance of truncated denitrification. Functional screening revealed the highest denitrification activity in two complete denitrifiers belonging to the genus Pseudomonas. These findings greatly expand the current knowledge of the composition and function of denitrifying microorganisms in subsoils. The constructed isolate library provided the first pool of subsoil-denitrifying microorganisms that could facilitate the development of microbe-based technologies for nitrate attenuation in groundwater.

Histopathologic evaluation system of African swine fever in wild boar infected with high (Arm07) and low virulence (Lv17/WB/Riel) isolates.

To understand the clinicopathological forms of African swine fever (ASF) in wild boar, it is crucial to possess a basic knowledge of the biological characteristics of the currently circulating ASF virus isolates. The aim of this work is to establish an accurate and comprehensive histopathologic grading system to standardize the assessment of the ASF lesions in wild boar. The study evaluated the differences between animals infected with a high virulence genotype II isolate (Arm07) (HVI) through intramuscular (IM) (n = 6) and contact-infected (n = 12) routes, alongside those orally infected with a low virulence isolate (Lv17/WB/Riel) (LVI) (n = 6). The assessment included clinical (CS), macroscopic (MS), and histopathologic (HS) scores, as well as viral loads in blood and tissues by real-time quantitative polymerase chain reaction (qPCR). Tissues examined included skin, lymph nodes, bone marrow, palatine tonsil, lungs, spleen, liver, kidneys, thymus, heart, adrenal glands, pancreas, urinary bladder, brain, and gastrointestinal and reproductive tracts. The HVI group exhibited a 100% mortality rate with elevated CS, MS, and HS values. Animals infected by contact (CS = 12; MS = 58.5; HS = 112) and those intramuscularly infected (CS = 14.8; MS = 47; HS = 104) demonstrated similar values, indicating that the route of infection does not decisively influence the severity of clinical and pathological signs. The LVI group showed a 0% mortality rate, an inconspicuous clinical form, minimal lesions (CS = 0; MS = 12; HS = 29), and a lower viral load. Histopathologic evaluation has proven valuable in advancing our comprehension of ASF pathogenesis in wild boar and paves the groundwork for further research investigating protective mechanisms in vaccinated animals.

Genomic characterization of an uncommon Delftia acidovorans isolate obtained from a Bulgarian immunocompetent outpatient diagnosed with bronchitis.

Delftia acidovorans is an aerobic, non-fermenting Gram-negative bacterium (NFGNB), found in soil, water and hospital environments. It is rarely clinically significant, most commonly affecting hospitalized or immunocompromised patients. The present study aimed to explore the genomic characteristics of a Bulgarian clinical D. acidovorans isolate (designated Dac759) in comparison to all strains of this species with available genomes in the NCBI Genome database (n = 34). Dac759 was obtained in 2021 from the sputum of a 65-year-old female immunocompetent outpatient with bronchitis. Species identification using MALDI-TOF mass spectrometry, antimicrobial susceptibility testing, whole-genome sequencing (WGS), and phylogenomic analysis were performed. The isolate demonstrated high-level resistance to colistin (16 mg L-1); resistance to gentamicin; reduced susceptibility to piperacillin, piperacillin-tazobactam, ceftazidime, cefepime, ciprofloxacin, and levofloxacin; and susceptibility to imipenem, meropenem, amikacin, and tobramycin. The observed genome size (6.43 Mb) and GC content (66.76%) were comparable with the accessible data from sequenced D. acidovorans genomes. A limited number of resistance determinants were identified in the assembled genome as follows: blaOXA-459, emrE, oqxB, and mexCD-oprJ. The phylogenomic analysis indicated a high heterogenicity of the included D. acidovorans genomes. In conclusion, to the best of our knowledge, this is the first documented case of a clinically relevant D. acidovorans isolate in Bulgaria. Unlike the majority of reports in the literature, Dac759 affected a patient with no malignancies or other preexisting comorbidities. With this in mind, its genome sequence is a valuable resource for the fundamental study of uncommon bacterial pathogens of public health importance.

Heat-stable whey protein isolate made using isoelectric precipitation and clarification.

Residual lipids (RL) in whey protein isolate (WPI) are detrimental to optimal functional applications (e.g., foaming and low turbidity) and contribute to off-flavor development during powder storage. The objective of this research was to prepare an experimental WPI by removing RL without using the traditional microfiltration process and compare its properties with commercially available WPI made using microfiltration and some other whey powders. We hypothesize that by adjusting the pH of whey to <5.0, we would be close to the isoelectric point of any remaining denatured proteins (DP) and phospholipoproteins (PLP), and therefore reduce electrostatic repulsion between these molecules. Furthermore, demineralization of the acidified whey protein solution by UF combined with diafiltration (DF) should reduce ionic hindrance to aggregation and thereby help with the aggregation of these DP as well as most RL; centrifugation or clarification could be used to remove these materials. Calcium should also be more extensively removed by this approach, which should improve the heat stability of the experimental WPI. Demineralization was achieved on a pilot scale by acidifying liquid (cheese) whey protein concentrate containing 34% protein (WPC-34) to pH 4.5 using HCl, and UF of the whey protein solution along with extensive DF using acidified (pH ∼3.5) reverse osmosis filtered water. Demineralized whey protein solution was adjusted to various combinations of pH (4.1-4.9), conductivities (500-2,000 µS/cm), and protein concentrations (1%-7%) and then centrifuged at 10,000 × g for 10 min. The effective sedimentation (precipitation) of RL in these treatments was estimated by measuring the turbidity of the supernatants. Maximum precipitation was observed at pH 4.5 to 4.7. Reducing conductivity via UF/DF increased the precipitation of RL due to reduced ionic hindrance to aggregation. Maximum sedimentation of RL was observed at protein concentrations ≤3% because of a higher density difference between the precipitate and serum phase. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis confirmed the sedimentation of phospholipoproteins, caseins, and DP upon isoelectric precipitation at pH ∼4.5, while native whey proteins or undenatured whey proteins remained soluble in the supernatant, unaffected by the pretreatment. To scale up the process, 750 L of fluid WPC-34 was acidified and demineralized by UF (volume concentration factor = 1.35) and DF until the permeate solids reached 0.1% (when desired demineralization was achieved), clarified using a pilot-scale desludging clarifier to remove RL, neutralized, ultrafiltered to concentrate the protein, and then spray-dried to produce an experimental WPI (91% protein and 1.8% fat on a dry basis [db]). In another trial, demineralized UF concentrate was clarified by gravity sedimentation and the supernatant was neutralized, ultrafiltered, and spray-dried to produce a second experimental WPI (91% protein and <1% fat db). These experimental WPI powders were compared with several commercially available WPI powders to assess functional properties such as solubility, heat stability, foamability and foam strength, gelation, and sensory attributes over accelerated storage. Experimental WPI had excellent functional properties, had low turbidity, were highly heat stable, and only developed very slight-to-slight off-flavors upon accelerated storage, and their properties were comparable to the WPI manufactured commercially using microfiltration even after accelerated storage.

Physicochemical properties of micellar casein retentates generated at different microfiltration temperatures.

Processing temperature has a significant influence on the composition and functionality of the resulting streams following microfiltration (MF) of skim milk. In this study, MF and diafiltration (DF) were performed at 4 or 50°C to produce ß-casein (ß-CN)-depleted and nondepleted (i.e., native casein profile) micellar casein isolate retentates, respectively. Microfiltration combined with extensive DF resulted in a 40% depletion of ß-CN at 4°C, whereas no ß-CN depletion occurred at 50°C. Microfiltration at 4°C led to higher transmission of calcium into permeates, with retentate generated at 4°C containing less total calcium compared with retentate generated at 50°C, based on the volume of retentate remaining. Higher heat stability at 120°C was measured for retentates generated at 4°C compared with those at 50°C, across all pH values measured. Retentates generated at 4°C also had significantly lower ionic calcium values at each pH compared with those generated at 50°C. Higher apparent viscosities at 4°C were measured for retentates generated at 4°C compared with retentates generated at 50°C, likely due to increased voluminosity of ß-CN-depleted casein micelles. The results of this study provide new information on how changing the composition of MF retentate, by appropriate control of processing temperature and DF, can alter physicochemical properties of casein micelles, with potential implications for ingredient functionality.

Identification and characterization of microorganisms isolated from noncompliant or atypical dairy products in Canada.

Despite good manufacturing practices and rigorous cleaning and sanitizing procedures established in dairy processing plants, microbiological contamination remains the main cause of products being noncompliant or atypical and hence not fit for human consumption. The objective of this study was to isolate, identify, and characterize bacteria, yeasts, and molds associated with substandard dairy products in Canada and to create a collection of reference isolates. In addition to conventional microbiological characterization, each isolate was tested for biofilm-forming ability and susceptibility to heat, antimicrobial agents, and common industrial disinfectants. Among the 105 microbial strains isolated from pasteurized milk, cream, and cheese samples, 24 bacterial isolates, belonging mainly to the genus Pseudomonas, were shown to be moderate or strong biofilm producers in 96-well plates and highly resistant to peracetic acid (100 ppm, 5 min contact time) and sodium hypochlorite (70 ppm, 5 min contact time). In addition, 56 bacterial isolates, including Acinetobacter baumannii, Enterobacter bugandensis, Klebsiella pneumoniae, and Pseudomonas spp., were found resistant to ampicillin, fosfomycin or ceftriaxone, while 14 others, such as Bacillus spp. and Macrococcus spp., withstood a heat treatment equivalent to low-temperature, long-time pasteurization (63°C for 30 min). This descriptive study provides new information on potential problematic microorganisms in dairies and will guide the development of novel control strategies intended to prevent and reduce microbiological contamination and the associated economic losses.

Alginate/whey protein isolate-based emulgel as an alternative margarine replacer in processed cheese: Impact on rheological, mechanical, nutritional, and sensory characteristics.

The effects of partial or full replacement of margarine by alginate/whey protein isolate-based olive oil emulgel on nutritional, physicochemical, mechanical, and rheological properties of processed cheese (PC) were investigated in this work. All formulated samples had the same amount of total fat, DM, and pH. According to the results of the fatty acids profile, the PC sample in which the margarine was fully replaced by the emulgel (EPC100) had the highest (49.84%) oleic acid content and showed a reduction of 23.7% in SFA compared with the control sample (EPC0; formulated just with margarine). In addition, EPC0 had the highest hardness among various cheese samples, which was also confirmed by its compact microstructure. Dynamic oscillatory measurements revealed that EPC100 had the highest crossover strain (or resistance to deformation). The high rigidity of this sample was related to the 3-dimensional structure of emulgel. According to the creep test results, EPC100 showed the lowest relative recovery (flowability). A high temperature dependency of viscoelastic moduli was observed in EPC0 at 42°C. No significant differences were observed between the color attributes and sensory properties of the various cheese samples. Alginate/whey protein isolate-based olive oil emulgel can be considered as a healthy margarine replacer in PC.

First report of leaf blight on pumpkin caused by Nigrospora sphaerica in China.

Pumpkin (Cucurbita moschata), which belongs to the gourd family (Cucurbitaceae), is widely planted throughout the world. In June 2023, many pumpkin plants (cv. Miben) displayed leaf blight and chlorosis in fields located in Suizhou (31.99°N, 113.02°E), Hubei Province, China. The disease incidence ranged from 30 to 40% in nine fields, 6.3 ha in total. The symptoms were irregularly shaped lesions that expanded along the mid-vein until the leaf turned brown and wilted. Fungal isolations were performed as described previously (Liu et al. 2023). Twenty pumpkin leaf samples with typical symptoms were collected and cut into 1 cm×1 cm pieces. The diseased tissue was surface-sterilized in 75% ethanol for 30 sec, plated on potato dextrose agar (PDA) medium and incubated at 25℃ for 3 days. Then, the emerging single fungal hyphal tip was transferred onto PDA plates to obtain purified isolates. A total of eighteen isolates on PDA plates were initially white and then developed to dark gray. The 5-day-old cultures growing on mung bean medium produced conidia that were black, single-celled, smooth, spherical or oblate, and ranged in size from 14.5 to 20.8 µm×13.3 to 20.5 µm (n=50). Therefore, the isolates were morphologically identified as Nigrospora sphaerica. Moreover, the genomic DNA of the isolates (HB-P1,HB-P2, and HB-P3) was extracted for amplification and sequencing of the regions of internal transcribed spacer (ITS) (White et al. 1990), nuclear large subunit rRNA (nLSU) (O'Donnell 1992; Rehner and Samuels 1994), and ß-tubulin (TUB2) (Glass and Donaldson 1995), with primers ITS1/ITS4, LROR/LR3, and Bt2a/Bt2b, respectively. Sequences were submitted to GenBank under accession numbers PP348112, PP348113, PP348114 (ITS), PP411414, PP411415, PP411416 (nLSU), and PP357438, PP357439, PP357440 (TUB2). BLASTn showed that the sequences ITS, nLSU, and TUB2 of HB-P1, HB-P2, and HB-P3 had >99% nucleotide identities ((ITS: 100%, 508/508 bp, MF996488.1; 99.8%, 506/507, ON326588.1; 100%, 500/500 ,MK748317.1), (nLSU: 99.83%, 573/574, KT462720.1; 99.83% , 574/575 bp, KT462720.1; 99.65%, 575/577, KT462720.1), and (TUB2: 100%, 388/388, MN719407.1; 99.74%, 387/388, MN719407.1; 100%, 387/387, MN719407.1)) with Nigrospora sphaerica, respectively. A multilocus (ITS, nLSU and TUB2) phylogenetic analysis indicated that the isolates were Nigrospora sphaerica. Pathogenicity of three isolates were tested on pumpkin plants (cv. Miben). Fifteen pumpkin plants were inoculated by spraying the leaves (1×106 spores/ml), respectively, and 10 pumpkin plants were treated with sterile water as a negative control. All plants were incubated in an artificial climate box (LongYue, ShangHai) at 25℃ for 12 days. The experiment was repeated three times. Twelve days later, the inoculated pumpkin plants developed symptoms of leaf blight, while the control plants remained healthy. Then, pathogens were re-isolated from the each leaf of inoculated pumpkin plants and not from the control plants. Nigrospora sphaerica has been previously reported to cause leaf spot on watermelon in Malaysia (Ismail and Abd Razak 2021). To our knowledge, this is the first report of N. sphaerica causing leaf blight on pumpkin in China. This new disease can cause leaf blight, which may affect pumpkin productivity.

Cross-Inoculation of Commercial Forestry, Amenity, and Horticulture Tree Species with Ceratocystis Isolates Collected from Different Host Species.

Ceratocystis manginecans has caused significant losses in forestry productivity in Indonesia and neighboring nations. It also infects horticultural trees, but the host range of individual isolates of C. manginecans is poorly studied. So, this study aimed to better understand the potential host range and evaluate aggressiveness against forestry and fruit tree species of C. manginecans isolated from various tree species in Indonesia. Five C. manginecans isolates, four from different tree species and one from the shot-hole borer Euwallacea perbrevis, were used to inoculate seven fruit and six forest tree species, including E. pellita and Acacia mangium. Many of the inoculated trees produced typical canker disease symptoms, such as rough, swollen, and cracked lesions on the bark, but some trees did not have any external symptoms. Mortality in the most susceptible clone of A. mangium was 40% within 8 weeks. Forest tree species were more susceptible than fruit trees, with the length of xylem discoloration ranging from 0.4 to 101 cm. In fruit trees, the average extent of xylem discoloration was lower, ranging from 0.4 to 20.5 cm; however, mortalities were recorded in two fruit tree species, Citrus microcarpa and Durio zibethinus. Host-isolate interaction was evident; isolate Ep106C from Eucalyptus pellita caused the greatest xylem discoloration in Citrus sp., whereas Hy163C from Hymenaea courbaril was the most damaging in D. zibethinus, Artocarpus heterophyllus, and Mangifera indica. Increasingly globalized food and fiber systems increase risk of disease spread, and the serious threat of C. manginecans incursions into countries where it is not present must be evaluated more thoroughly.

Whey Protein Isolate as a Substrate to Design Calendula officinalis Flower Extract Controlled-Release Materials.

The use of natural active substances and the development of new formulations are promising directions in the cosmetic and pharmacy industries. The primary purpose of this research was the production of microparticles based on whey protein isolate (WPI) and calcium alginate (ALG) containing Calendula officinalis flower extract and their incorporation into films composed of gelatin, WPI, and glycerol. Both swollen and dry microparticles were studied by optical microscopy and their sizes were measured. Water absorption by the microparticles, their loading capacity, and the release profile of flower extract were also characterized. The films were analyzed by mechanical tests (Young's modulus, tensile strength, elongation at break), swelling capacity, contact angle, and moisture content measurements. The presented data showed that the active ingredient was successfully enclosed in spherical microparticles and completely released after 75 min of incubation at 37 °C. The incorporation of the microparticles into polymer films caused a decrease in stiffness and tensile strength, simultaneously increasing the ductility of the samples. Moreover, the films containing microparticles displayed higher swelling ability and moisture content compared to those without them. Hence, the materials prepared in this study with Calendula officinalis flower extract encapsulated into polymeric microspheres can be a starting point for the development of new products intended for skin application; advantages include protection of the extract against external factors and a controlled release profile.

Enhancing Functional Properties and Protein Structure of Almond Protein Isolate Using High-Power Ultrasound Treatment.

The suitability of a given protein for use in food products depends heavily on characteristics such as foaming capacity, emulsifiability, and solubility, all of which are affected by the protein structure. Notably, protein structure, and thus characteristics related to food applications, can be altered by treatment with high-power ultrasound (HUS). Almonds are a promising source of high-quality vegetable protein for food products, but their physicochemical and functional properties remain largely unexplored, limiting their current applications in foods. Here, we tested the use of HUS on almond protein isolate (API) to determine the effects of this treatment on API functional properties. Aqueous almond protein suspensions were sonicated at varying power levels (200, 400, or 600 W) for two durations (15 or 30 min). The molecular structure, protein microstructure, solubility, and emulsifying and foaming properties of the resulting samples were then measured. The results showed that HUS treatment did not break API covalent bonds, but there were notable changes in the secondary protein structure composition, with the treated proteins showing a decrease in α-helices and ß-turns, and an increase in random coil structures as the result of protein unfolding. HUS treatment also increased the number of surface free sulfhydryl groups and decreased the intrinsic fluorescence intensity, indicating that the treatment also led to alterations in the tertiary protein structures. The particle size in aqueous suspensions was decreased in treated samples, indicating that HUS caused the dissociation of API aggregates. Finally, treated samples showed increased water solubility, emulsifying activity, emulsifying stability, foaming capacity, and foaming stability. This study demonstrated that HUS altered key physicochemical characteristics of API, improving critical functional properties including solubility and foaming and emulsifying capacities. This study also validated HUS as a safe and environmentally responsible tool for enhancing desirable functional characteristics of almond proteins, promoting their use in the food industry as a high-quality plant-based protein.

Adenosine Encapsulation and Characterization through Layer-by-Layer Assembly of Hydroxypropyl-ß-Cyclodextrin and Whey Protein Isolate as Wall Materials.

Adenosine, as a water-soluble active substance, has various pharmacological effects. This study proposes a layer-by-layer assembly method of composite wall materials, using hydroxypropyl-ß-cyclodextrin as the inner wall and whey protein isolate as the outer wall, to encapsulate adenosine within the core material, aiming to enhance adenosine microcapsules' stability through intermolecular interactions. By combining isothermal titration calorimetry with molecular modeling analysis, it was determined that the core material and the inner wall and the inner wall and the outer wall interact through intermolecular forces. Adenosine and hydroxypropyl-ß-cyclodextrin form an optimal 1:1 complex through hydrophobic interactions, while hydroxypropyl-ß-cyclodextrin and whey protein isolate interact through hydrogen bonds. The embedding rate of AD/Hp-ß-CD/WPI microcapsules was 36.80%, and the 24 h retention rate under the release behavior test was 76.09%. The method of preparing adenosine microcapsules using composite wall materials is environmentally friendly and shows broad application prospects in storage and delivery systems with sustained release properties.

Optimization of Ultrasound-Assisted Microwave Encapsulation of Peanut Oil in Protein-Polysaccharide Complex.

Research background: Peanut oil (Arachis hypogaea L.) is a rich source of unsaturated fatty acids. Its consumption has been reported to have biological effects on human health. Unsaturated, especially polyunsaturated fatty acids (PUFA) found in peanut oil are highly susceptible to oxidation, leading to the formation of harmful compounds during processing and storage. The aim of this study is to prevent the oxidation of peanut oil PUFA by encapsulation in a protein-polysaccharide complex using microwave drying. Experimental approach: The combined effect of corn starch (CS) and whey protein isolate (WPI) was evaluated for ultrasound-assisted microwave encapsulation of peanut oil to prevent oxidative degradation. The effect of independent parameters, viz. CS:WPI mass ratio (1:1 to 5:1), lecithin mass fraction (0-5 %), ultrasonication time (0-10 min) and microwave power (150-750 W) on the encapsulation of peanut oil was evaluated using response surface methodology (RSM). The process responses, viz. viscosity and stability of the emulsion, encapsulation efficiency, peroxide value, antioxidant activity, free fatty acids (FFA), moisture, angle of repose and flowability (Hausner ratio (HR) and Carr's Index (CI)) were recorded and analysed to optimize the independent variables. Results and conclusions: The viscosity of all emulsions prepared for encapsulation by ultrasonication ranged from 0.0069 to 0.0144 Pa·s and more than 90 % of prepared combinations were stable over 7 days. The observed encapsulation efficiency of peanut oil was 21.82-74.25 %. The encapsulation efficiency was significantly affected by the CS:WPI mass ratio and ultrasonication. The peroxide value, antioxidant activity and FFA ranged from 1.789 to 3.723 mg/kg oil, 19.81-72.62 % and 0.042-0.127 %, respectively. Physical properties such as moisture content, angle of repose, HR and CI were 1.94-8.70 %, 46.5-58.3°, 1.117-1.246 and 10.48-22.14 %, respectively. The physical properties were significantly affected by surface properties of the capsules. The higher efficiency (74.25 %) of peanut oil encapsulation was achieved under optimised conditions of CS:WPI mass ratio 1.25, 0.25 % lecithin, 9.99 min ultrasonication and 355.41 W microwave power. Novelty and scientific contribution: The results of this work contribute to the fields of food science and technology by providing a practical approach to preserving the nutritional quality of peanut oil and improving its stability through encapsulation, thereby promoting its potential health benefits to consumers and applications in various industries such as dairy and bakery.

The structural and functional properties of hemp protein isolate-epigallocatechin-3-gallate biopolymer covalent complex during heating.

BACKGROUND: It is well known that hemp proteins have the disadvantages of poor solubility and poor emulsification. To improve these shortcomings, an alkali covalent cross-linking method was used to prepare hemp protein isolate-epigallocatechin-3-gallate biopolymer (HPI-EGCG) and the effects of different heat treatment conditions on the structure and emulsifying properties of the HPI-EGCG covalent complex were studied. RESULTS: The secondary and tertiary structures, solubility, and emulsification ability of the HPI-EGCG complexes were evaluated using particle size, zeta potential, circular dichroism (CD), and fluorescence spectroscopy indices. The results showed that the absolute value of zeta potential of HPI-EGCG covalent complex was the largest, 18.6 mV, and the maximum binding amount of HPI to EGCG was 29.18 µmol g-1 . Under heat treatment at 25-35 °C, the α-helix content was reduced from 1.87% to 0%, and the ß-helix content was reduced from 82.79% to 0% after the covalent binding of HPI and EGCG. The solubility and emulsification properties of the HPI-EGCG covalent complexes were improved significantly, and the emulsification activity index (EAI) and emulsion stability index (ESI) were increased by 2.77-fold and 1.21-fold, respectively. CONCLUSION: A new HPI-EGCG covalent complex was developed in this study to provide a theoretical basis for the application of HPI-EGCG in food industry. © 2023 Society of Chemical Industry.

Effect of ultrasonic frequency on the structural and functional properties of pea protein isolation.

BACKGROUND: Pea protein, as a by-product of peas (Pisum sativum L.), is rich in a variety of essential amino acids that can meet the body's protein needs and is a valuable source of protein. Since the function of pea protein is closely related to its structure, pea protein has been subjected to different modifications in recent years to improve its application in food and to develop new products. RESULTS: The effects of sonication frequency (primary and secondary time) on pea protein isolate's (PPI's) structural and functional properties were investigated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that different sonication frequencies at the same power (600 W) treatment had no effect on PPI's molecular weight. Fourier-transform infrared spectroscopy revealed that treatment at different sonication frequencies caused secondary structural changes in PPI. The particle size distribution, foaming, stability, surface hydrophobicity, emulsification, and oxidation resistance of PPI were improved after primary and secondary sonication, but secondary sonication was not more effective than primary sonication for an extended period of time. CONCLUSION: Overall, ultrasound is able to improve the structural and functional properties of pea proteins within a suitable range. It provides a theoretical basis for elucidating the modification of the structure and function of plant proteins by ultrasound and lays the foundation for the development of plant proteins in food applications as well as development. © 2023 Society of Chemical Industry.

Fabrication of soy protein-polyphenol covalent complex nanoparticles with improved wettability to stabilize high-oil-phase curcumin emulsions.

BACKGROUND: Recent studies have shown that the wettability of protein-based emulsifiers is critical for emulsion stability. However, few studies have been conducted to investigate the effects of varying epigallocatechin gallate (EGCG) concentrations on the wettability of protein-based emulsifiers. Additionally, limited studies have examined the effectiveness of soy protein-EGCG covalent complex nanoparticles with improved wettability as emulsifiers for stabilizing high-oil-phase (≥ 30%) curcumin emulsions. RESULTS: Soy protein isolate (SPI)-EGCG complex nanoparticles (SPIEn) with improved wettability were fabricated to stabilize high-oil-phase curcumin emulsions. The results showed that EGCG forms covalent bonds with SPI, which changes its secondary structure, enhances its surface charge, and improves its wettability. Moreover, SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) exhibited a better three-phase contact angle (56.8 ± 0.3o) and zeta potential (-27 mV) than SPI. SPIEn-2.0 also facilitated the development of curcumin emulsion gels at an oil volume fraction of 0.5. Specifically, the enhanced network between droplets as a result of the packing effects and SPIEn-2.0 with inherent antioxidant function was more effective at inhibiting curcumin degradation during long-term storage and ultraviolet light exposure. CONCLUSION: The results of the present study indicate that SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) comprises the optimum conditions for fabricating emulsifiers with improved wettability. Additionally, SPIEn-0.2 can improve the physicochemical stability of high-oil-phase curcumin emulsions, suggesting a novel strategy to design and fabricate high-oil-phase emulsion for encapsulating bioactive compounds. © 2024 Society of Chemical Industry.

Effect of electron beam irradiation on glycosylation reaction and structural characterization of whey isolate protein.

BACKGROUND: Whey protein isolate (WPI) is a high-quality animal protein resource. The modification of WPI through physical, chemical and biological methods can substantially improve the functional properties of proteins. This study investigated the effect of electron beam irradiation (EBI) on the modification of WPI-xylose glycosylation. RESULTS: The degree of grafting and browning revealed that EBI promoted WPI glycosylation. The maximum emission wavelength of intrinsic fluorescence was red-shifted and the fluorescence intensity was reduced, suggesting that irradiation induced the unfolding of the WPI structure, thereby promoting glycosylation. Fourier-transformed infrared spectroscopy revealed that the covalent binding of the conjugates occurred on the introduction of the hydrophilic groups, resulting in decreased surface hydrophobicity. When compared with conventional wet-heat glycosylation, irradiation-assisted glycosylation improved the emulsifying activity of WPI from 179.76 ± 0.83 to 277.83 ± 1.44 m2 g-1, and the emulsifying and rheological properties improved. CONCLUSION: These results confirmed that EBI can increase the degree of WPI glycosylation and improve the functional properties of proteins, thereby laying a theoretical foundation for the further application of WPI. © 2024 Society of Chemical Industry.