Effect of Curcumin on Physicochemical and Gel Properties of Pork Myofibrillar Proteins under Oxidative Condition

To explore the effects of different curcumin concentrations on the gel properties of pork myofibrillar proteins (MPs), changes in gel whiteness, cooking loss, water retention capacity, texture, dynamic rheology, intermolecular forces, microstructure, and protein electropherograms were evaluated after being treated with different concentrations of curcumin (0, 5, 10, 15 and 20 μmol/L) in a simulated oxidative system with 5 mmol/L H2O2. The results indicated that the addition of curcumin benefited the formation of a more stable and compact protein gel network structure and alleviated gel softening, structure loosening, decreased water-holding capacity, increased cooking loss and other problems caused by oxidation. Additionally, the rheological characterization revealed that the addition of curcumin enhanced both storage modulus (G’) and loss modulus (G”) of MP gels under oxidative conditions, thereby promoting the formation of elastic gels with stable three-dimensional network structures and improving the gel characteristics of MPs. Moreover, higher curcumin concentration within a certain range was more beneficial for gel formation

Effects of Portulaca oleracea Extracts on Gelation and Emulsification Properties of Pork Myofibrillar Proteins

This study aimed to investigate the effects of Portulaca oleracea extracts (PE) on the gelation and emulsification properties of pork myofibrillar proteins (MPs). A myofibrillar protein-Fenton oxidation system (0.0049 g/L FeCl3, 0.0176 g/L ascorbic acid, 5 mmol/L H2O2) was established, and different concentrations of PE (0.00, 2.00, 4.00, 8.00 mg/mL) were added. The changes in gelation and emulsification properties of MPs were analyzed to assess the impact of PE on the functional characteristics of MPs in pork tenderloin under oxidative conditions. The results demonstrated that PE significantly reduced the cooking loss of the gel (P<0.01) and improved its water-holding capacity (P<0.01) compared with the oxidation control group. Specifically at a concentration of 4.00 mg/mL, the addition of PE resulted in a 6.72% decrease in cooking loss and a 11.98% increase in water-holding capacity compared with the oxidation control group. However, the addition of PE led to a significant decrease in the whiteness of the gel (P<0.05), with the degree of whiteness being inversely related to the concentration of PE. Furthermore, the addition of PE increased the storage modulus (G') and loss modulus (G'') of the gel. At a concentration of 4.00 mg/mL PE, the microscopic structure of the gel exhibited greater regularity and order than that after oxidation, with an increase of 10.10% in hardness and 7.16% in elasticity. SDS-PAGE results indicated that the cross-linking between PE and proteins could be reduced, and PE significantly enhanced the emulsifying activity and emulsifying stability of the proteins (P<0.01). Overall, based on the comprehensive findings, it can be concluded that 4.00 mg/mL PE effectively inhibits the oxidation of MPs and improves the functional characteristics of proteins

A case report of neurosyphilis coexisting with a positive MOG antibody manifested as optic neuritis

BackgroundNeurosyphilis refers to an infection of the central nervous system by Treponema pallidum. The clinical manifestations of neurosyphilis are diverse, making it easy to miss or misdiagnose. Anti-myelin oligodendrocyte glycoprotein antibody-associated disease is a recently defined immune-mediated inflammatory demyelinating central nervous system disease. Few studies have reported the coexistence of the two diseases.Case presentationThis case report presents a 37 years-old male patient with neurosyphilis manifested as optic neuritis with a positive myelin oligodendrocyte glycoprotein (MOG) antibody. This patient received intravenous administration of 3.2 million units of procaine penicillin every 4 h for 2 weeks, followed by a two-week intramuscular injection of benzathine penicillin. Additionally, methylprednisolone sodium succinate was administered intravenously at 1,000 mg/day, gradually reduced to 500 mg/day and 240 mg/day every 3 days. Subsequently, prednisone tablets at a dosage of 60 mg/day were orally administered, with a gradual reduction of 5 mg/day every 3 days until reaching a dosage of 30 mg/day. The patient’s visual acuity was improved after 26 days of hospitalization. However, the visual field and color vision did not. At 3 months of follow-up, the symptoms remained unchanged despite the patient continued taking oral prednisone tablets at a dosage of 30 mg/day.ConclusionNeurosyphilis could be a potential triggering factor for MOGAD. In patients with neurosyphilis, it is strongly recommended to perform testing for MOG antibody along with other brain disease antibodies

Overview of Human Walking Induced Energy Harvesting Technologies and Its Possibility for Walking Robotics

This study is mainly to provide an overview of human walking induced energy harvest. Focusing on the proportion of all energy sources provided by daily activity, the available human walking induced energy is divided with respect to the generation principle. The extensive research on harvesting energy results from body vibration, inertial element, and foot press to convert into electricity is overviewed. Over the past decades, various smart materials have been employed to achieve energy conversion. Generators based on electromagnetic induction or the triboelectric effect were developed and integrated. Small captured power and low overall efficiency are criticized. The concept of human walking energy harvest is extended into the wearable walking robotics using other mediums, such as fluid, to transmit power instead of electricity. By comparison, it is indicated that less energy conversion links are involved in energy regeneration of such applications and expected to guarantee less loss and higher efficiency. Meanwhile, in order to overcome the shortage of relatively low power output, comments are made that the harvester should be capable of adaptation under the condition that the mechanical energy of lower limb and feet is subject to change in different gait phases so as to maximize the collected energy

Effects of <i>Gnaphalium affine</i> Extract on the Gel Properties of •OH-Induced Oxidation of Myofibrillar Proteins

This study aimed to investigate the effect of Gnaphalium affine extract (GAE) (0.04, 0.2 and 1 mg/g protein) on the gel properties of porcine myofibrillar proteins (MPs) in a simulated Fenton oxidation system, using tea polyphenols (TPs) at similar concentrations of 0.04, 0.2, and 1 mg/g protein, respectively, as a contrast. The findings revealed that as the TP concentration increased, the water retention of MP gels decreased significantly (p p p < 0.05) by 33.32% compared with the oxidized control group, suggesting that low and medium GAE concentrations support MP gel formation. A texture profile analysis indicated that an appropriate GAE concentration improved gel structure and texture. Dynamic rheological characterization revealed that low concentrations of TP (0.04 mg/g protein) and low and medium concentrations of GAE (0.04 and 0.2 mg/g protein) strengthened the protein gel system. Conversely, high concentrations of TP and GAE (1.0 mg/g protein) damaged the protein gel system or even promoted the collapse of the gel system. Scanning electron microscopy revealed that higher TP concentrations disrupted the gel, whereas low and medium GAE concentrations maintained a more continuous and complete gel network structure compared with the oxidized control group. This indicates that an appropriate GAE concentration could effectively hinder the destruction of the gel network structure by oxidation. Therefore, based on the obtained results, 0.2 mg/g protein is recommended as the ideal concentration of GAE to be used in actual meat processing to regulate the oxidization and gel properties of meat products