摘要：
According to the methodical examination of the physicochemical, sensory, and antioxidant properties of flavored yogurts which fortified with different amounts of Lentinula edodes stipe (LES), we found that the LES was beneficial to improve some physicochemical (pH, viable lactic acid bacteria density, and syneresis) and sensory properties (fermented odor and taste quality), and the antioxidant activity (ABTS and DPPH radical scavenging activity) of the plain yogurt, which has the potential to be used in functional yogurt. The results above were also helpful for the rational utilization of LES toward value‐added products. Abstract The Lentinula edodes stipe (LES), a by‐product of L. edodes fruiting body processing, is rich in dietary fiber, protein, and polysaccharides, which can be served as the functional ingredient in dairy products. In this study, stirred yogurts fortified with 1%, 2%, and 3% LES were prepared, and the effects of LES on the changes in color, pH, titratable acidity (TA), viable lactic acid bacteria (LAB) cells, syneresis, viscosity, texture, and antioxidant activity of the flavored yogurt were monitored at the beginning and the end of storage. The LES decreased the lightness, increased the red–green color values and yellow–blue color values, decreased the pH values, and increased the contents of TA, the viable LAB cells, and the antioxidant activity of yogurt samples in a dose‐dependent manner. The addition of LES showed double‐edged effects on the texture of yogurt, which significantly reduced firmness and viscosity but decreased the syneresis. Compared with plain yogurt, the 2% LES‐fortified yogurt exhibited similar index values of texture parameters and higher scores of the appearance, fermented odor, taste quality, and overall acceptance, suggesting that this might be the optimal dose for industrial production. After cold storage for 28 days, pH values of all yogurt samples further decreased with increasing of TA. Interestingly, syneresis of LES‐fortified yogurt decreased and the viable LAB cells and antioxidant activity of 3% LES‐fortified yogurt slightly decreased. Therefore, LES is beneficial to improve physicochemical, sensory, and antioxidant properties of yogurt, which has the potential to be used in functional dairy products.
摘要：
An unrecorded wild mushroom Lactarius hatsudake from Nanyue mountainous region in China was identified. Subsequently, comparative investigation on the nutritional value, elemental bioaccumulation, and antioxidant activity was performed in the fruiting body (FB) and mycelium (MY) samples of this species. It revealed that the contents of moisture (87.66 & PLUSMN; 0.16 g/100 g fw) and ash (6.97 & PLUSMN; 0.16 g/100 g dw) were significantly higher in FB, and the total carbohydrate, fat, and protein concentrations of FB were similar to those in MY. Among nutritionally important elements, FB possessed higher concentrations of potassium (37808.61 & PLUSMN; 1237.38 mg/kg dw), iron (470.69 & PLUSMN; 85.54 mg/kg dw), and zinc (136.13 & PLUSMN; 5.16 mg/kg dw), whereas MY was a better source of magnesium (1481.76 & PLUSMN; 18.03 mg/kg dw), calcium (2203.87 & PLUSMN; 69.61 mg/kg dw), and sodium (277.44 & PLUSMN; 22.93 mg/kg dw). According to the health risk estimation, FB might pose an aluminum-related health problem when a prolonged period of exposure, while MY was risk-free for consumers. The results of antioxidant capacity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2 & PRIME;-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays) in FB and MY were within the range of 104.19 & PLUSMN; 5.70 mg ascorbic acid equivalents (AAE)/g to 169.50 & PLUSMN; 4.94 mg AAE/g, and half maximal effective concentration EC50 values ranged from 0.23 & PLUSMN; 0.01 mg/ mL to 0.62 & PLUSMN; 0.05 mg/mL. The aqueous extracts of MY demonstrated a strong ABTS radical scavenging capacity with the highest AAE value.
摘要：
In this paper, a nanocomposite of cuprous oxide and electrochemically reduced graphene oxide (Cu2O-ERGO) was prepared by a simple and low-cost method; hereby, a new method for the electrochemical determination of tryptophan (Trp) by this composite modified glassy carbon electrode (GCE) is proposed. The prepared materials and modified electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and cyclic voltammetry (CV). The results showed that Cu2O-ERGO/GCE had good electrocatalytic activity for Trp. The effects of supporting electrolyte, scanning rate, accumulation potential, and accumulation time on the determination of Trp were studied. Under the optimum experimental conditions, Trp was quantitatively analyzed by square-wave voltammetry (SWV). The oxidation peak current of Trp had a good linear relationship with its concentration in the range of 0.02-20 M, and the detection limit was 0.01 M (S/N = 3). In addition, the modified electrode has high sensitivity, good repeatability, and long-term stability. Finally, the proposed method has been successfully applied in the determination of Trp concentration in practical samples.
作者机构：
[He, Quanguo; Li, Guangli; Tian, Yaling; Wu, Yiyong; Liu, Jun] Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Hunan Prov Key Lab Funct Met Organ Cpds, Hengyang 421008, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Hengyang 421008, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.;[He, Quanguo; Deng, Peihong; Deng, PH; Chen, Dongchu] Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Peoples R China.
通讯机构：
[Deng, Peihong] H;[Deng, PH; Chen, DC] F;Hengyang Normal Univ, Hunan Prov Key Lab Funct Met Organ Cpds, Hengyang 421008, Peoples R China.;Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Hengyang 421008, Peoples R China.;Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.
摘要：
In this paper, a tryptophan (Trp) molecularly imprinted chitosan film was prepared on the surface of an acetylene black paste electrode using chitosan as the functional polymer, Trp as the template molecule and sulfuric acid as the crosslinking agent. The surface morphologies of non-imprinted and imprinted electrodes were characterized by scanning electron microscopy (SEM). The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy. Some factors affecting the performance of the imprinted electrode such as the concentration of chitosan, the mass ratio of chitosan to Trp, the dropping amount of the chitosan-Trp mixture, the solution pH, and the accumulation potential and time were discussed. The experimental results show that the imprinted electrode exhibit good affinity and selectivity for Trp. The dynamic linear ranges of 0.01-4 mu M, 4-20 mu M and 20-100 mu M were obtained by second derivative linear sweep voltammetry, and the detection limit was calculated to be 8.0 nM. The use of the imprinted electrode provides an effective method for eliminating the interference of potentially interfering substances. In addition, the sensor has high sensitivity, reproducibility and stability, and can be used for the determination of Trp in pharmaceutical preparations and human serum samples.
作者机构：
[He, Quanguo; Li, Guangli; Tian, Yaling; Wu, Yiyong; Liu, Jun] Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Hengyang 421008, Peoples R China.;[He, Quanguo; Tian, Yaling; Deng, Peihong; Wu, Yiyong] Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.;[He, Quanguo; Chen, Dongchu] Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Peoples R China.
通讯机构：
[Deng, Peihong] H;[Chen, Dongchu] F;Hengyang Normal Univ, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Peoples R China.;Hengyang Normal Univ, Key Lab Funct Organometall Mat Hunan Prov Univ, Hengyang 421008, Peoples R China.;Hengyang Normal Univ, Dept Chem & Mat Sci, Hengyang 421008, Peoples R China.
摘要：
The morphology or shape of nanomaterials plays an important role in functional applications, especially in the electrochemical sensing performance of nanocomposites modified electrodes. Herein, the morphology-dependent electrochemical sensing properties of MnO2-reduced graphene oxide/glass carbon electrode (MnO2-RGO/GCE) toward dopamine detection were investigated. Firstly, various morphologies of nanoscale MnO2, including MnO2 nanowires (MnO2 NWs), MnO2 nanorods (MnO2 NRs), and MnO2 nanotubes (MnO2 NTs), were synthesized under different hydrothermal conditions. Then the corresponding MnO2-RGO/GCEs were fabricated via drop-casting and the subsequent electrochemical reduction method. The oxidation peak currents increase with the electrochemical activity area following the order of MnO2 NWs-RGO/GCE, MnO2 NTs-RGO/GCE, and MnO2 NRs-RGO/GCE. The spatial models for MnO2 NWs, MnO2 NTs, and MnO2 NRs are established and accordingly compared by their specific surface area, explaining well the evident difference in electrochemical responses. Therefore, the MnO2 NWs-RGO/GCE is selected for dopamine detection due to its better electrochemical sensing performance. The response peak current is found to be linear with dopamine concentration in the range of 8.0 × 10−8 mol/L–1.0 × 10−6 mol/L and 1.0 × 10−6 mol/L–8.0 × 10−5 mol/L with a lower detection limit of 1 × 10−9 mol/L (S/N = 3). Finally, MnO2 NWs-RGO/GCE is successfully used for the determination of dopamine injection samples, with a recovery of 99.6–103%. These findings are of great significance for understanding the relationship between unlimited nanoparticle structure manipulation and performance improvement.
