A novel non-centrifugal sugar prepared from tiger nut (Cyperus esculentus L.) meal: Preparation methods and comparison with sugarcane.

The lack of research on the rich sucrose in tiger nut meal has been a major obstruction to the comprehensive utilization of tiger nut (Cyperus esculentus L.). In this study, for the first time, tiger nut meal was used to producing non-centrifugal sugar (NCS). Three samples - NCS-W1 (NCS prepared by water extraction and concentrated at 115 °C), NCS-W2 (NCS prepared by water extraction and concentrated at 135 °C), and NCS-E (NCS prepared by 70 % ethanol-water extraction and concentrated at 115 °C) were obtained, with yields of 14.25-14.59 %. These samples and sugarcane NCS products (NCS-C1, NCS-C2, NCS-L) were compared and analyzed in terms of color, pH, turbidity, soluble solid content, and proximate composition. Their Fourier-transformed infrared spectra, crystal patterns, and thermal stabilities were also analyzed. The NCS-W1, -W2, and -E showed excellent performance, and they were better than sugarcane NCS products in terms of free radical scavenging ability and cytoprotective effects. Differences in phenolic acid composition, flavonoid composition, amino acid, mineral content, and vitamins C and E content were also analyzed. This work demonstrates that tiger nut meal might be a new source of NCS. As such it would contribute to the full utilization of tiger nut.

A Heat and Mass Transfer Model of Peanut Convective Drying Based on a Two-Component Structure.

In order to optimize the convective drying process parameters of peanuts and to provide a theoretical basis for the scientific use of energy in the drying process, this study took single-particle peanuts as the research object and analyzed the heat and mass transfer process during convective drying. In addition, a 3D two-component moisture heat transfer model for peanuts was constructed based on the mass balance and heat balance theorem. Moreover, the changes in the internal temperature and concentration fields of peanut pods during the whole drying process were investigated by simulations using COMSOL Multiphysics. The model was validated by thin-layer drying experiments, compared with the one-component model, and combined with low-field NMR technology to further analyze the internal moisture distribution state of peanut kernel drying process. The results show that both models can effectively simulate the peanut thin-layer drying process, and consistency is found between the experimental and simulated values, with the maximum errors of 10.25%, 9.10%, and 7.60% between the simulated moisture content and the experimental values for the two-component model, peanut shell, and peanut kernel models, respectively. Free water and part of the weakly bound water was the main water lost by peanuts during the drying process, the change in oil content was small, and the bound water content was basically unchanged. The results of the study provide a theoretical basis to accurately predict the moisture content within different components of peanuts and reveal the mechanism of moisture and heat migration during the drying process of peanut pods.

Corrigendum: Characterization of structure and antioxidant activity of polysaccharides from sesame seed hull.

[This corrects the article DOI: 10.3389/fnut.2022.928972.].

Characterization of Structure and Antioxidant Activity of Polysaccharides From Sesame Seed Hull.

Sesame seed hull is the major by-product of sesame seed processing and is rich in polysaccharides. In this work, sesame hull polysaccharides (SHP) were extracted by ultrasound-assisted alkali extraction methods with a yield of 6.49%. Three purified polysaccharide fractions were obtained after decolorization, deproteinization, and column chromatography. Then, their main composition and antioxidant activity were investigated. The dominant fraction was SHP-2 with a yield of 3.78%. It was composed of galacturonic acid (51.3%), glucuronic acid (13.8%), rhamnose (8.9%), glucose (8.4%), and others. The linkage types of SHP-2 have the α-D-GalpA-(1,4)-linked, α-D-GlcpA-(1,2)-linked, ß-T-D-Rhap-linked, ß-D-Glcp-(1,6)-linked, ß-T-D-Galp-linked, α-L-Xylp-(1,4)-linked, α-L-Araf-(1,3,5)-linked, and ß-D-Manp-(1,4)-linked. This study might provide some useful basic data for developing applications for sesame seed hull polysaccharides in the food and pharmaceutical industries.

l-Cysteine directing synthesis of BiOBr nanosheets for efficient cefazolin photodegradation: The pivotal role of thiol.

Cefazolin (CFZ) is widely present in the wastewater treatment effluents and in receiving waters and has caused severe impacts to the ecosystem. CFZ degradation by photocatalysis has attracted increasing attention due to its eco-friendly features. Herein, we presented a green synthesis strategy for a highly active BiOBr photocatalyst for CFZ removal with L-cysteine as a directing agent, and the role of thiol in cysteine for facets control and morphology regulation was discussed. We found that the photoactivity of cysteine-induced BiOBr nanosheet was much higher than those prepared by using arginine and glycine as directing agent. Further experiments showed that the cysteine preferentially coordinated Bi3+ with thiol rather than carboxyl. The strong interactions of thiol group with the external surface of the BiOBr crystals stabilize the small crystals that have high surface energy without the cysteine. Such a chemical environment favors forming BiOBr crystalline with small size of high surface area and oriented growth in [110] direction, which facilitates the photogenerated electron-hole separation to achieve significantly promoted photocatalytic activity. Moreover, the cysteine-directed BiOBr nanosheets displayed good photoreactivity to more pollutants (i.e. rhodamine B, cefradine and cefoperazone sodium) and excellent reusability as verified via seven consecutive recycle experiments. The proper photocatalyst dosage (0.4 g/L), relatively acidic water environment (pH 3.4) and high temperature (35 °C) would be beneficial to CFZ photodegrdation by BiOBr. Also, the CFZ photodegradation mechanism and degradation pathway were also proposed by combining radical trapping experiments and electron spin resonance (ESR) test with LC-MS analysis in the photocatalytic process.

Effects of ultrasonic vacuum drying on the drying kinetics, dynamic moisture distribution, and microstructure of honey drying process.

The aim of this study was to study the strengthening effect of ultrasonic vacuum technique on the drying kinetics, moisture distribution, and microstructure of honey using low-field nuclear magnetic resonance and scanning electron microscopy. Results showed that ultrasonic vacuum drying technique could substantially shorten the drying time from 600 to 60 min, compared with vacuum drying. The sonochemical effects of ultrasonic vacuum drying were enhanced with the increased ultrasonic power and were more obvious in the initial stage of drying. This finding is consistent with the effective water diffusion coefficient results. The non-linear fitting analysis of experimental data on seven kinds of thin-layer drying mathematical models showed that logarithmic model is more suitable for describing the law of moisture change in honey during ultrasonic vacuum drying than the other models because of its higher regression coefficient value (≥0.99) and smaller reduced chi-square and root mean square error values (≤0.01). In addition, low-field nuclear magnetic resonance results showed that the increase in ultrasonic power accelerated the migration of bound water to immobilized water in honey samples. Scanning electron microscopy results showed that the porous structure formed by increasing the ultrasonic power is also conducive to the rapid migration and drying of moisture. In conclusion, ultrasonic vacuum drying technique is an effective and safe way for drying viscous materials compared with vacuum drying technique.

Characterization and macrophage immunomodulatory activity of two polysaccharides from the flowers of Paeonia suffruticosa Andr.

Paeonia suffruticosa Andr. has a long history of cultivation in China and its flower possesses high nutritional and medicinal value. Characterization and macrophage immunomodulatory activity of the two polysaccharides from the flowers of Paeonia suffruticosa Andr., PSAP-1 and PSAP-2, purified by anion exchange chromatography followed by size exclusion chromatography, were investigated in the present study. Results showed that PSAP-1, with a molecular weight of 155 kDa, was mainly composed of glucuronic acid, glucose, arabinose and galactose with molar percentages of 0.83, 11.53, 18.98 and 68.96% respectively, and PSAP-2, with a molecular weight of 210 kDa, consisted of rhamnose, galacturonic acid, glucose, arabinose and galactose with molar percentages of 9.13, 8.35, 12.20, 14.75 and 55.57% respectively. Immunostimulatory activity evaluation in vitro revealed that the PSAP-1 and PSAP-2 could significantly stimulate the proliferation of Raw264.7 cells in dose-dependent manner and further activate Raw264.7 cells by releasing immunoactive molecules such as nitric oxide, tumor necrosis factor (TNF)-α and interleukin (IL)-6. In addition, PSAP-2 had higher immunomodulatory activity than PSAP-1. The above results suggested that both PSAP-1 and PSAP-2 had potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent in medicine or functional food fields.

Effects of low molecular sugars on the retrogradation of tapioca starch gels during storage.

The effects of low molecular sugars (sucrose, glucose and trehalose) on the retrogradation of tapioca starch (TS) gels stored at 4°C for different periods were examined with different methods. Decrease in melting enthalpy (ΔHmelt) were obtained through differential scanning calorimetry analysis. Analysis of decrease in crystallization rate constant (k) and increase in semi-crystallization time (τ1/2) results obtained from retrogradation kinetics indicated that low molecular sugars could retard the retrogradation of TS gels and further revealed trehalose as the best inhibitor among the sugars used in this study. Fourier transform infrared (FTIR) analysis indicated that the intensity ratio of 1047 to 1022 cm-1 was increased with the addition of sugars in the order of trehalose > sucrose > glucose. Decrease in hardness parameters and increase in springiness parameters obtained from texture profile analysis (TPA) analysis also indicated that low molecular sugars could retard the retrogradation of TS gels. The results of FTIR and TPA showed a consistent sugar effect on starch retrogradation with those of DSC and retrogradation kinetics analysis.

MRT letter: localization of endogenous hydrogen peroxide by modified processes of sample preparation for transmission electron microscope in Escherichia coli.

The bacterial endogenous hydrogen peroxide (H(2)O(2)) was detected cytochemically by its reaction with cerium chloride (CeCl(3)) to produce electron-dense deposits of cerium perhydroxides. The sequence of fixation and CeCl(3) staining of H(2)O(2) in the processing of transmission electron microscope (TEM) sample preparation is crucial to the localization of endogenous H(2)O(2) in Escherichia coli. In this study, results confirmed that the process that fixation simultaneously with CeCl(3) staining provided optimum effects for H(2)O(2) localization in E. coli. The modified process of TEM provides very efficient protection for H(2)O(2) localization and more accurate quantization for the H(2)O(2) accumulation in bacterial cells.

Evaluation of the sedative and hypnotic effects of Eucommiol in Eucommia.

The purpose of this study was to evaluate the sedative and hypnotic effects of Eucommiol, a monomer compound extracted from male Eucommia flowers using a system solvent method. Eucommiol shows significant effects in mice, including reduced spontaneous activity, and increased the sleep ratio or lengthened the sleep time with a subthreshold or superthreshold dose of pentobarbital sodium, respectively. In addition, could effectively shorten sleep latency, reduce convulsion rate and prolong convulsion latency. These findings intensely indicated that Eucommiol has excellent sedative and hypnotic effects.

Effect of juice and fermented vinegar from Hovenia dulcis peduncles on chronically alcohol-induced liver damage in mice.

The protective effects of juice and fermented vinegar from Hovenia dulcis peduncles on chronically ethanol-induced biochemical changes in male mice were investigated. Administration of ethanol (50%, v/v, 10 mL kg⁻¹) to mice for 6 weeks induced liver damage with a significant increase (P < 0.01) of the liver index, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyl transferase (γ-GT) in the serum and the hepatic lipid peroxidation (LPO) level. In contrast, administration of juice or fermented vinegar from Hovenia dulcis peduncles (10 mL kg⁻¹ bw) along with alcohol significantly (P < 0.05) decreased the activities of the enzymes (AST, ALT and γ-GT), liver index, concentrations of triglyceride (TG) and total cholesterol (TCH) in the serum and the hepatic TG and LPO levels. Mice treated with juice or fermented vinegar from Hovenia dulcis peduncles showed better profiles of the antioxidant systems with relatively higher glutathione (GSH) content, total superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. All these results were accompanied by histological observations in liver. The results demonstrate that both of the juice and fermented vinegar from Hovenia dulcis peduncles have beneficial effects in reducing the adverse effect of alcohol.

Modeling the QSAR of ACE-Inhibitory Peptides with ANN and Its Applied Illustration.

A quantitative structure-activity relationship (QSAR) model of angiotensin-converting enzyme- (ACE-) inhibitory peptides was built with an artificial neural network (ANN) approach based on structural or activity data of 58 dipeptides (including peptide activity, hydrophilic amino acids content, three-dimensional shape, size, and electrical parameters), the overall correlation coefficient of the predicted versus actual data points is R = 0.928, and the model was applied in ACE-inhibitory peptides preparation from defatted wheat germ protein (DWGP). According to the QSAR model, the C-terminal of the peptide was found to have principal importance on ACE-inhibitory activity, that is, if the C-terminal is hydrophobic amino acid, the peptide's ACE-inhibitory activity will be high, and proteins which contain abundant hydrophobic amino acids are suitable to produce ACE-inhibitory peptides. According to the model, DWGP is a good protein material to produce ACE-inhibitory peptides because it contains 42.84% of hydrophobic amino acids, and structural information analysis from the QSAR model showed that proteases of Alcalase and Neutrase were suitable candidates for ACE-inhibitory peptides preparation from DWGP. Considering higher DH and similar ACE-inhibitory activity of hydrolysate compared with Neutrase, Alcalase was finally selected through experimental study.

Effect of energy-gathered ultrasound on Alcalase.

This research was to explore the mechanism of ultrasonic impact on protease activity. The effects of energy-gathered ultrasound on the activity, kinetics, thermodynamics and molecular structure of Alcalase were investigated with the aid of the chemical reaction kinetics model, Arrhenius equation, Eyring transition state theory, fluorescence spectroscopy and circular dichroism (CD) spectroscopy. Results showed that ultrasound had effect on the activity of Alcalase. The highest Alcalase activity was achieved when the sample was treated with energy-gathered ultrasound at 80 W for 4 min, under which the enzyme activity was increased by 5.8% over the control. After the treatment, thermodynamics parameters Ea, ΔH, ΔS and ΔG were reduced by 70.0%, 75.8%, 34.0% and 1.3%, respectively. Besides, fluorescence and CD spectra revealed that the ultrasonic treatment had increased the number of tryptophan on Alcalase surface slightly, increased number of α-helix by 5.2%, and reduced the number of random coil by 13.6%.