Effect of electron beam irradiation on raw goat milk: microbiological, physicochemical and protein structural analysis.

BACKGROUND: Goat milk is considered a nutritionally superior resource, owing to its advantageous nutritional attributes. Nevertheless, it is susceptible to spoilage and the persistence of pathogens. Electron beam irradiation stands as a promising non-thermal processing technique capable of prolonging shelf life with minimal residue and a high degree of automation. RESULTS: The effects of electron beam irradiation (2, 3, 5, and 7 kGy) on microorganisms, physicochemical properties, and protein structure of goat milk compared with conventional pasteurized goat milk (PGM) was evaluated. It was found that a 2 kGy electron beam irradiation reduces the total microbial count of goat milk by 6-logs, and the irradiated goat milk protein secondary structure showed a significant decrease in ɑ-helix content. Low irradiation doses led to microaggregation and crosslinking. In contrast, high doses (≥ 5 kGy) slightly disrupted the aggregates and decreased the particle size, disrupting the microscopic surface structure of goat milk, verified by scanning electron microscopy and confocal laser scanning microscopy. CONCLUSION: The irradiation of goat milk with a 2 kGy electron beam may effectively inactivate harmful microorganisms in the milk and maintain/or improve the physicochemical quality and protein structure of goat milk compared to thermal pasteurization. © 2024 Society of Chemical Industry.

Effect of electron beam irradiation on the structural characteristics and functional properties of goat's milk casein.

The effects of electron beam irradiation (EBI) at different doses (0, 2, 4, 6, 8, and 10 kGy) were investigated on the structural and functional properties of casein, including their interrelationship. A gradual reduction in the α-helix content of the secondary structure (as a stable structure) indicates that casein under EBI treatment mainly undergoes fragmentation and aggregation from a structural perspective. Furthermore, the hydrophobic group and tryptophan in the tertiary structure were exposed, which opened up the internal structure of the protein. In addition, a continuously increasing irradiation dose led to casein aggregation, as confirmed by electron microscopy. The structural changes affected its functional properties, such as solubility, emulsification, foaming, and rheological properties, all of which increased first and subsequently decreased. Finally, at irradiation doses of 4-6 kGy, casein was modified to exhibit optimal functional properties, which enhanced its food processing value and performance.

X-rays irradiation maintains redox homeostasis and regulates energy metabolism of fresh figs (Ficus carica L. Siluhongyu).

In this study, figs were irradiated with X-rays doses of 1.0, 3.0, and 5.0 kGy and stored at 4 °C for 20 d to evaluate effects of X-ray on redox homeostasis and energy metabolism in figs. Non-irradiated figs were recorded as control group. Results indicated that 3.0 kGy X-rays delayed fig color discoloration by inhibiting the ΔE* values. The electrolyte leakage, MDA and O2-· levels of figs were significantly alleviated. Energy metabolism assay revealed that 3.0 kGy X-rays could significantly maintain higher activities of H+-ATPase, Ca2+-ATPase, SDH, CCO, G6PDH and 6PGDH of figs. 3.0 kGy X-rays also retained mitochondria membrane integrity of figs. Furthermore, 3.0 kGy X-rays resulted in 26.09 % higher NADK activity and 16.30 % lower NADH content than the control. The study proves that X-ray irradiation can be used as figs preservation means to maintain redox homeostasis and regulate energy metabolism, thus lengthening the shelf life of figs.

Comparative investigation of the effects of electron beam and X-ray irradiation on potato starch: Structure and functional properties.

Electron beam (particle radiation) and X-ray (electromagnetic radiation) without radioisotope in the application of material modification have received increasing attention in the last decade. To clarify the effect of electron beam and X-ray on the morphology, crystalline structure and functional properties of starch, potato starch was irradiated using electron beam and X-ray at 2, 5, 10, 20 and 30 kGy, respectively. Electron beam and X-ray treatment increased the amylose content of starch. The surface morphology of starch did not change at lower doses (< 5 kGy), but starch granules were aggregated with the increase of doses. All treatments decreased crystallinity, viscosity and swelling power but increased solubility and stability properties. The effects of electron beam and X-ray on the starch had a similar trend. Unlike X-ray, electron beam destructed the crystallinity of starch to a lesser extent, thereby increasing thermal stability and freeze-thaw stability. Furthermore, X-ray irradiation at higher doses (> 10 kGy) resulted in outstanding anti-retrogradation properties of starch compared with electron beam treatment. Thus, particle and electromagnetic irradiation displayed an excellent ability to modify starch with respective specific characteristics, which expands the potential application of these irradiations in the starch industry.

Lipidomics reveals alterations of lipid composition and molecular nutrition in irradiated marble beef.

Electron beam irradiation can effectively inhibit microbial growth, but the changes of lipid during irradiation have not been comprehensively analyzed in marble beef. Here, UHPLC-MS/MS was used to detect lipids changes of irradiated marble beef. A total of 1032 lipids were identified and classified into 3 lipid classes and 8 subclasses in irradiated marble beef. 9 lipid biomarkers were screened with increasing irradiation dose. 122 differential lipids were generated and involved in 4 metabolic pathways included Glycerophospholipid metabolism, Linoleic acid metabolism, alpha-Linolenic acid metabolism and Arachidonic acid metabolism though PC(18:0/14:0), PE(16:0/16:0) and PE(18:0/16:0) in irradiated. Our results showed that irradiation had effect on the lipid of marbled beef, but the increase of irradiation dose from 2.5 kGy to 4.5 kGy had little effect on lipids. These results help us to understand the dynamic changes of irradiated meat lipids and lay a foundation for the application of irradiation in meat preservation.

Inactivation of two SARS-CoV-2 virus surrogates by electron beam irradiation on large yellow croaker slices and their packaging surfaces.

The detection of infectious SARS-CoV-2 in food and food packaging associated with the cold chain has raised concerns about the possible transmission pathway of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in foods transported through cold-chain logistics and the need for novel decontamination strategies. In this study, the effect of electron beam (E-beam) irradiation on the inactivation of two SARS-CoV-2surrogate, viruses porcine epidemic diarrhea virus (PEDV) and porcine transmissible gastroenteritis virus (TGEV), in culture medium and food substrate, and on food substrate were investigated. The causes of virus inactivation were also investigated by transmission electron microscopy (TEM) and Quantitative Real-time PCR (QRT-PCR). Samples packed inside and outside, including virus-inoculated large yellow croaker and virus suspensions, were irradiated with E-beam irradiation (2, 4, 6, 8, 10 kGy) under refrigerated (0 °C)and frozen (-18 °C) conditions. The titers of both viruses in suspension and fish decreased significantly (P < 0.05) with increasing doses of E-beam irradiation. The maximum D10 value of both viruses in suspension and fish was 1.24 kGy. E-beam irradiation at doses below 10 kGy was found to destroy the spike proteins of both SARS-CoV-2 surrogate viruses by transmission electron microscopy (TEM) and negative staining of thin-sectioned specimens, rendering them uninfectious. E-beam irradiation at doses greater than 10 kGy was also found to degrade viral genomic RNA by qRT-PCR. There were no significant differences in color, pH, TVB-N, TBARS, and sensory properties of irradiated fish samples at doses below 10 kGy. These findings suggested that E-beam irradiation has the potential to be developed as an efficient non-thermal treatment to reduce SARS-CoV-2 contamination in foods transported through cold chain foods to reduce the risk of SARS-CoV-2 infection in humans through the cold chain.

A new pre-gelatinized starch preparing by spray drying and electron beam irradiation of oat starch.

As a green and safe physical technology, irradiation is increasingly used to improve starch properties. In the study, oat starch was pre-gelatinized at 70 °C followed by spray drying. Subsequently, the spray-dried starch (SDS) was exposed to electron beam (e-beam) irradiation at different doses to obtain new pre-gelatinized starch. Spray drying caused a decrement in the ratio of long B3 chains and the molecular weight of starch. Spray-dried starch (SDS) slightly increased solubility and swelling power than native starch. When SDS was subjected to e-beam irradiation, its solubility and swelling power increased dramatically, but the pasting viscosities, gelatinization temperatures, apparent viscosity, storage modulus (G') and lost modulus (G″) reduced. The depolymerization of starch molecules and the breakage of amylopectin chains might be responsible for changing the physicochemical properties of e-beam irradiated starch. These results showed that spray drying combined with e-beam irradiation would potentially produce new pre-gelatinized starch.

Design of the Artificial Intelligence Vocal System for Music Education by Using Speech Recognition Simulation.

At present, computer technology is not limited to the network but to many aspects of spread out, including artificial intelligence technology, signal processing technology, speech recognition technology, and so on which have been better developed, and music teaching has also obtained certain achievements. If the detected speech data have no other clutter in the speech, then the endpoint detection can achieve ideal results. The music education system includes the development of four dimensions: WEB terminal, mobile terminal, web interface, and database. Using the powerful functions of computers, such as computing functions and processing functions, combined with advanced intelligent technology and related equipment, the intelligent learning model based on computer technology is established. It can be applied in college teaching, combined with the actual needs of current college music teaching, corresponding to the curriculum and teaching plan issued by the school, combined with the design of online learning system and reasonable use of computer technology to build a vocal music education system. The intelligent system can improve the requirements of vocal music education management level, teaching organization ability, and teaching platform operation ability.

Electron beam irradiation regulates the structure and functionality of ball-milled corn starch: The related mechanism.

The ball milling (BM), electron beam irradiation (EBI), the combination of them, and their effects on granules morphology, multiscale structure, physicochemical properties, and digestibility of corn starch are discussed in this paper. Both BM and EBI reduced crystallinity, amylopectin molecular weight (Mw), pasting viscosities, gelatinization temperatures, and resistant starch (RS) content, but increased amylose Mw and rapidly digestible starch content. BM treatment damages the starch granules, which makes them easier to attack by free radicals of subsequent EBI treatment. In addition, the BM pretreatment promoted starch chain depolymerization and crystalline structure destruction, reinforcing the joint effect of subsequent EBI treatment. Therefore, BM-EBI-starches exhibited lessened crystallinity, amylopectin Mw, pasting viscosities, gelatinization temperatures, enthalpy and RS content than native and single-treated starch. This paper would like to reference potential industrial applications of BM and EBI technologies to modify starch.

Effects of Penicillium expansum infection on the quality and flavor of yellow flesh kiwifruit during cold storage.

This study aimed to assess the effects of Penicillium expansum (P. expansum) infection on the quality and flavor of Jinmi (JM) and Jinyan (JY) kiwifruit. Kiwifruit were inoculated with P. expansum and stored at 0 ± 1°C, and the changes in quality indicators and volatile substances (VCs) at different stages of disease were determined. Results showed that in wound-inoculated kiwifruit, the soluble solid content (SSC) increased. Conversely, their titratable acidity and vitamin C (VC) content, firmness, lightness, and saturation decreased. The taste-related parameters and nutritional value of kiwifruit declined after infection. VCs such as ethanol, 3-methyl-1-butanol, and 2-methylisoborneol were detected only in the diseased fruit and gradually increased as the disease aggravated, suggesting that they may be the main sources of odor during P. expansum infection. Therefore, VCs detection can be used to determine possible P. expansum infection, as well as the degree of infection in kiwifruit. PRACTICAL APPLICATIONS: In practical application, we can use the results of this study to determine possible Penicillium expansum infection, as well as the degree of infection in kiwifruit according to the indicators such as volatile substances. Kiwifruit enterprises can use the nondestructive detection model established in this study to screen out the kiwifruit infected with P. expansum more efficiently, quickly, and accurately, in order to prevent harm to the health of consumers.

Expression and clinical significance of HSP27 and its phosphorylation in lower extremity arteriosclerosis obliterans.

OBJECTIVES: This study set out to analyze the difference of heat shock protein 27 (HSP27) and its phosphorylation in patients with lower extremity arteriosclerosis obliterans (LEASO) at different stages. This research also examined their clinical significance in this disease. METHODS: Blood samples from 60 patients with LEASO were collected and divided into two groups according to ankle-brachial index (ABI): group A (ABI ≤ 0.43) and group B (ABI > 0.43). The expression of HSP27 in each stage of Fontaine was measured by ELISA, and the difference of HSP27 concentration and ABI between the two groups was analyzed. Meanwhile, three normal femoral artery specimens (normal group) and three atherosclerotic femoral artery specimens (lesion group) were collected, and HSP27 and its Phospho-HSP27 (Ser15), Phospho-HSP27 (Ser78) and Phospho-HSP27 (Ser82) were detected by western blotting. The data of the protein level between the normal group and the lesion group was made a statistical analysis. RESULTS: HSP27 concentration in group A was (40.73 ± 15.99) ng/ml, and ABI was 0.26 ± 0.20. HSP27 concentration in group B was (66.30 ± 24.70) ng/ml, and ABI was 0.64 ± 0.20. The protein expression of HSP27 and its phosphorylation in the normal group was 0.82 ± 0.13, 0.66 ± 0.12, 0.91 ± 0.24 and 0.90 ± 0.16, respectively; the protein expression of the lesion group was 0.45 ± 0.08, 0.42 ± 0.09, 0.39 ± 0.12 and 0.58 ± 0.11. CONCLUSION: Patients with higher LEASO Fontaine stage and lower ABI had a lower HSP27 concentration. Serum HSP27 concentration was negatively correlated with the severity of LEASO, while HSP27 concentration was positively correlated with ABI value. The content of HSP27 and its phosphorylation of lesion group is significantly lower than that of normal group, which may be closely related to the occurrence and development of atherosclerosis.

Difference of resistance to postharvest blue mold between Hongyang and Qihong kiwifruits.

This study aimed to reveal the physiological mechanism of resistance to postharvest blue mold of kiwifruit. Hongyang and Qihong kiwifruits were inoculated with Penicillium expansum (P. expansum) and stored at low temperature (0 ±â€¯1 °C). The disease incidence and lesion diameter, activities of defense-related enzymes, and contents of defense-related substance of Hongyang and Qihong kiwifruits were also compared, combined with the observation of fruit pericarp structure by scanning electron microscopy. Results showed that the disease resistance of Hongyang was stronger than that of Qihong with late onset, low incidence, and small lesion diameter. And Hongyang kiwifruit showed a high biochemical resistance after inoculation with P. expansum. The epidermis structure of Hongyang kiwifruit had typical disease resistance characteristics with a dense epidermis structure, orderly cell arrangement, and less obvious microcracks. The strong biochemical resistance, dense, and complete epidermis structure of Hongyang fundamentally guarantee its strong resistance to diseases.

[Experimental study on adhesiveness of osteoblasts and vascular endothelial cells from rat BMSCs co-cultured on allogeneic freeze-dried partially bone in vitro].

OBJECTIVE: To investigate the adhesiveness of osteoblasts and vascular endothelial cells from rat BMSCs. METHODS: The BMSCs were isolated from 4-week-old SD co-cultured on allogeneic freeze-dried partially bone in vitro. rats (weighing 100-110 g) and cultured in vitro. The third generation of BMSCs were induced into osteoblasts and vascular endothelial cells. The osteoblasts and vascular endothelial cells after being induced for 7 days in a ratio of 1 to 1 were directly co-cultured (experimental group), while the second generation of uninduced BMSCs was used as a control (control group). The growth and proliferation ability were analyzed by MTT examination and the growth curve was drawn at 1-8 days. The osteoblasts and vascular endothelial cells after being induced for 14 days were implanted in the allogeneic freeze-dried partially bone coated by 20% Col I or not at different densities (0.25 x 10(6)/mL, 0.50 x 10(6)/mL, 1.00 x 10(6)/mL, 2.00 x 10(6)/mL, 4.00 x 10(6)/mL), as modified group and unmodified group, the cell adherence rate was calculated after 24 hours. These two kinds of cells were implanted in the pre-disposal treated allogeneic freeze-dried partially bone and observed by scanning electron microscope. RESULTS: ALP staining of osteoblasts showed that there were blue grains in cytoplasm at 7 days. CD31 and CD34 immunocytochemical staining of vascular endothelial cell showed that there were positive signals in the cytoplasm at 14 days. The MTT test showed that the proliferation level of the experimental group was lower than those of the control group. There were significant differences in absorbance value between two group from 3 days to 8 days (P < 0.05). The cell adherence rate increased with increasing seeding density when the seeding density was (0.25-1.00) x 10(6)/mL. The cell adherence rate reached the peak when the seeding density was 1.00 x 10(6)/mL. The cell adherence rate decreased when the seeding density was more than 2.00 x 106/mL. There were significant differences in cell adherence rate between modified group and unmodified group at different seeding densities (P < 0.05). The proliferation of the osteoblasts and endothelial cells presented better growth and histocompatibility under scanning electron microscope. CONCLUSION: The growing behavior of two kinds of cells is good in the allogeneic freeze-dried partially bone coated by 20% Col I, which can be used in reconstruction of vascularized tissue engineered bone.

[Experimental study on tissue engineering platelet lysates in the promotion of bone reconstruction].

OBJECTIVE: To evaluate the effects of tissue engineered allogeneic platelet lysates (PL) upon bone reconstruction. METHODS: After preparation of recombinant material with PL, allogeneic decalcified bone granules (ADBG) and collagen type I (CG), 30 healthy Wistar rats were used to prepare the bilateral bone defects in femoral condyles. The defects were filled with equivalent PL/ADBG/CG, ADBG/CG and CG in different groups of A, B and C (with 10 rats each) respectively. At 4 weeks, the defect reconstruction was evaluated with radiology, histology, immunology and biomechanics. RESULTS: (1) The X-ray showed that bone density in group A (4.18 +/- 0.96) was close to that of normal bone and it was significantly higher than that in group B (2.36 +/- 0.87) and group C (1.09 +/- 0.55) (P < 0.01). (2) In comparisons with B and C, the histological assay revealed that there were markedly more activities of new bone formation and more implanted bone granules surviving without significant lymphocyte infiltration, as well as more osteoclastic bone resorption in group A. The bone histomorphometric assay showed the newly formed bone area in group A (286.73 +/- 17.22) was significantly higher than that in group B (94.34 +/- 33.56) and group C (19.12 +/- 14.53) (P < 0.01). (3) Anti-press mechanical measures showed that the destructive load in A, B, C and normal control group was 259.63 +/- 34.57, 187.90 +/- 21.07, 91.33 +/- 26.58 and 311.93 +/- 82.45 respectively. The destructive energy in A, B, C and normal control group was 10.82 +/- 1.44, 7.83 +/- 0.88, 3.81 +/- 1.11 and 12.97 +/- 3.43 respectively. These results showed either destructive load or destructive energy in group A was markedly higher than that in group B and group C with significant difference (P < 0.01), but still lower than that in normal controls (P < 0.01). (4) Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3+CD4+CD8-, CD3+CD8+CD4- and the ratio of CD4/CD8 showed no significance difference within these three groups as well as normal controls. CONCLUSION: Tissue engineering PL (PL/ADBG/CG) is capable of accelerating the regenerative repair of bone defect and promoting the bone regeneration and osetointergretion of allograft bone after transplantation.