Pretreatment Methods Research Articles

Investigation of near infrared and Raman fibre optic process sensors for protein determination in milk protein concentrate

This study investigated the potential of two fibre optic process sensors based on near infrared (NIR) or Raman spectroscopic technology for protein measurement in milk protein concentrate (MPC). Partial least squares (PLS) models were developed using NIR, Raman, and fusion of NIR and Raman spectra data. Calibration models developed were optimized by selecting different spectral pre-treatment methods and spectral regions. Overall, the three optimal models (NIR, Raman, fused NIR and Raman) yielded R2p values >0.9 and RMSEP values in the range of 0.168–0.185 %. The optimised fusion model outperformed all Raman models and had a similar protein prediction accuracy (R2p = 0.911 and RMSEP = 0.178 %) compared to the optimised NIR model (R2p = 0.917 and RMSEP =0.168 %). Results of the study demonstrated that both NIR and Raman process probes can be used as process analytical technology (PAT) tools for inline protein measurements of MPC post membrane filtration.

Impact of ultrasonic pretreatment on the color and antioxidant capacity of vacuum freeze-dried strawberries

To enhance the color quality and antioxidant potential of vacuum-freeze-dried strawberry tablets, ultrasonic waves were used as a freezing pretreatment. Results revealed that the * values of freeze − dried strawberries following ultrasonic pretreatment improved significantly by ∼60% and the C* values increased by 34.36%–51.65%. These findings suggest that ultrasonic pretreatment results in a brighter coloration of the strawberry samples. The ultrasound − assisted freezing treatment groups exhibited a significantly higher free radical scavenging ability compared with the nonultrasonic treatment group. This enhancement was attributed to the ultrasonic pretreatment, which increased the concentrations of total phenolic compounds, flavonoids, and anthocyanins, and effectively inhibited the activities of polyphenol oxidase and peroxidase, thereby reducing the content of red pigment in the strawberry samples. Furthermore, confocal laser scanning microscopy revealed a uniform distribution of sugar within the samples following ultrasonic treatment. Cluster analysis indicated that the primary indices influencing the color of the samples were total phenolic content and peroxidase activity. Therefore, the ultrasonic pretreatment method effectively enhances product color, inhibits enzyme activity, and increases anthocyanin content. This technology holds promising development prospects.

The matrix effect derived from proteins in fluorescence detection for ciprofloxacin residues in eggs

Based on the previously developed Al3+/CuNCs probe, the matrix effect (ME) derived from protein was investigated in the fluorescence determination of fluoroquinolones (FQs) residues in eggs, and a sample pretreatment method was established to rapidly reduce the ME. Molecular docking results indicated that the three main egg proteins and FQs were bound by hydrogen bond, van der Waals force, and alkyl groups, leading to the loss of FQs response signal, and then produced ME. After trichloroacetic acid treatment, the mean particle size of egg matrix decreased, the protein secondary structure changed, and the crystal structure was destroyed. The corresponding ME of the supernatant obtained by centrifugation was only 0.7 %. The standard addition experiment confirmed that the proposed pretreatment method improved the accuracy and reliability of the fluorescence probe. This work is helpful to promote the practical application of fluorescence analysis in the rapid monitoring of food safety hazard factors.

Extraction and Characterization of Microcrystalline Cellulose (MCC) from Durian Rind for Biocomposite Application

The scientific community has become interested in cellulose extraction from agro-industrial wastes because they contain large quantities of cellulose and are being researched globally due to their application. Cellulose extracted from these wastes offers varying characteristics and structures depending on the specific source. In this study, microcrystalline cellulose (MCC) was extracted from different parts of the durian husk through acid hydrolysis with various concentrations of oxalic acid and cellulose-to-acid ratios. The durian husk underwent a pretreatment method involving bleaching and alkaline treatment. The characteristics of MCC, such as functional group, morphology, and crystallinity, were studied. The findings indicated that lignin was successfully removed through pretreatment. However, traces of hemicellulose were still detected in a few samples. The extracted MCCs demonstrated a diameter range from 6.237 to 25.38 μm and crystallinity within the range of 71.43–78.30%. Polycaprolactone (PCL)-based biocomposites with different MCC weights (0.2, 0.5, and 1.0 wt%) were fabricated, and the performance was evaluated through tensile testing and biodegradability tests. The addition of 1.0 wt% MCC enhanced the tensile strength by 22%. SEM analysis revealed the cross-section fracture surface of the biocomposite, indicating the contribution of the MCC during pull-out. Meanwhile, the biodegradability of the biocomposite increased with the addition of MCC, indicating that the MCC-based biocomposite was fully biodegradable.

Pre-treatment of waste hydrated cement used for replacement of fine aggregate using amine-based CO2 solvent

In the realm of construction and demolition (C&D) waste, a small fraction of hydrated cement waste is typically repurposed to generate supplementary cementitious material or filler for concrete. However, the conventional method of utilizing it in powder form demands significant energy consumption to achieve the necessary fineness. Therefore, this study proposes a method to use a waste-hydrated cement paste as a fine aggregate as well as the pre-treatment method to enhance its properties. The pre-treatment involves carbonating hydrated cement in a fully CO2-dissolved amine-based CO2 solvent, specifically a monoethanolamine (MEA) solution. This process eliminates vulnerable phases, such as calcium hydroxide, resulting in a higher compressive strength of mortar when incorporating the treated hydrated cement as fine aggregate. Notably, the use of fully CO2-dissolved 1% and 10% MEA solutions during carbonation demonstrates superior performance and increased CO2 uptake. Additionally, the developed pre-treatment method uses MEA CO2 solvent directly, commonly utilized for CO2 capture in industrial flue gas. It is an alternative for solvent regeneration without the need for a heating process, potentially reducing overall energy consumption.

Enhanced production of bioethanol through supercritical carbon dioxide-mediated pretreatment and saccharification of dewaxed bagasse

The pretreatment and saccharification of dewaxed bagasse (DWB) has been investigated under various reaction conditions ranging 2000 to 3200 psi, at 70 ± 1 °C in supercritical carbon dioxide (SCC). This has been in attempt to transform the DWB into fermentable sugar and bioethanol in high yields. The effect of SCC mediated pretreatment and enzymatic hydrolysis on structural and morphological alterations in DWB has been ascertained through diverse analytical methods. The sugar has been released through cellulase (40 FPU/mL) mediated enzymatic hydrolysis of pretreated DWB in sodium acetate buffer (pH 4.7) within 1 h at SCC 2800 psi, 70 ± 1 °C. The released sugar was subsequently fermented in the presence of yeast (Saccharomyces crevices, 135 CFU) at 28 ± 1 °C over 72 h to afford the bioethanol. The SCC mediated process conducted in acetic acid:water media (1:1) at 2800 psi, 70 ± 1 °C over 6 h has afforded the pretreated DWB with maximum yield towards the production of fermentable sugar and bioethanol. The production of fermentable sugar and bioethanol has been electrochemically estimated through cyclic voltammetry (CV) and square wave voltammetry (SWV) over glassy carbon electrode in KOH (0.1 M). The electrochemical methods were found selective and in close agreement for estimation of the yields (%) of fermentable sugars and bioethanol. The yield (%) of fermentable sugar estimated from CV and SWV were 80.10 ± 5.34 and 79.00 ± 5.09 respectively. Whereas the yield (%) of bioethanol estimated from CV and SWV were 81.30 ± 2.78% and 78.6 ± 1.25% respectively. Present investigation delivers a SCC mediated green and sustainable method of pretreatment of DWB to afford the enhanced saccharification, to produce bioethanol in high yields.

Preparation and evaluation of Fe3O4@C@NiCo-LDH@CDs composites for magnetic solid-phase extraction of trace endocrine disruptors.

The widespread use of endocrine disruptors (EDPs) has certain potential hazards to organisms and environments, and it is particularly important to develop effective pretreatment methods before detection of EDPs in complex samples. In this work, a novel magnetic nanocomposite decorated with layered double hydroxides (LDHs) and carbon dots (CDs) was designed and prepared for magnetic solid-phase extraction (MSPE) of EDPs (bisphenol S, bisphenol F, bisphenol A, bisphenol AF, diethylstilbestrol and 4-cumylphenol) combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. The prepared composites were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the adsorption mechanism towards these EDPs might be mainly based on hydrogen bonds and π-π conjugation. Under the optimized conditions, the proposed method showed limits of detection within 0.05-0.50 μg L-1 and limits of quantitation within 0.2-2.0 μg L-1, and good linearity (R2 ≥ 0.9975) was presented in the range of 0.2-200 μg L-1. Finally, the Fe3O4@C@NiCo-LDH@CDs composite-based MSPE-HPLC-UV method was applied for enrichment and determination of EDPs in water, milk, and tea beverage samples with recoveries in the range of 81.2-119.8% and relative standard deviations below 9.7%.

Microplastics in food: Occurrence, toxicity, green analytical detection methods and future challenges

The pervasive presence of microplastics (MPs) in the environment has raised significant concerns about their infiltration into the human food chain. In current review, the occurrence and distribution of MPs in various food matrices such as seafood, drinking water, fruits, vegetables, and beverages are discussed along with their potential routes of MPs entry into the human food chain. The toxicity of MPs on human health and different organs are discussed in brief. Current technological advancement and green analytical methods for the detection of MPs in food samples are compared, discussing their advantages and limitations. Green analytical methods, including stereomicroscopy, Fourier Transform Infrared spectroscopy, Raman spectroscopy, and enzymatic digestion, are evaluated for their efficacy and environmental impact. The Analytical Eco-Scale is used to assess the greenness of these methods. Challenges associated with MPs detection in food, such as complex food matrices, pretreatment methods, and variability in MPs concentrations, are addressed.

A novel microwave-assisted γ-valerolactone and glycolic acid pretreatment for green and sustainable production of hemp fibres

Hemp, a sustainable crop, offers superior material properties suitable for diverse applications. This study aims to produce hemp fibre using a green and sustainable pretreatment method, thus exploring a novel microwave-assisted pretreatment method using a γ-valerolactone (GVL) and glycolic acid (GA) solution system, referred to as the GVL/GA pretreatment method. By optimising solid loading and reaction time, we significantly reduced water usage (50 %) and energy consumption (61.5 %) while maintaining fibre quality. The pretreatment method effectively removed lignin (88.7 %) and hemicellulose (39.3 %) without damaging the cellulose structure. The pretreated samples demonstrated a 45.7 % increase in glucose yield. Additionally, the characterisation of pretreated fibres revealed impressive fineness (4.4 dtex) and tenacity (4.0 cN/dtex), and the crystal structure remained intact with increased crystallinity (86 %). The HSQC NMR analysis unveiled that lignin undergoes structural modifications, enabling efficient lignin removal. GVL/GA pretreatment promotes green chemistry by minimising environmental impact and waste, using renewable resources. It provides a sustainable alternative to traditional methods, contributing to a greener industry.

Facile fabrication of the immuno-MALDI-MS chip for the enrichment of abused drug in human urine integrated with MALDI-MS analysis

BackgroundDrug abuse can result in both physical and mental health issues for individuals, and can also contribute to broader societal problems. The number of drug abuse cases rose to 296 million in 2021. The sample pretreatment methods commonly employed typically require longer processing times and occasionally necessitate derivatization. Furthermore, with the increase in sample sizes, traditional chromatography-mass spectrometry methods for analyzing abused drugs were no longer sufficient to handle such numerous samples. In this study, immuno-MALDI-MS chip were fabricated for specific enrichment of illicit drugs, integrating with the rapid and accurate capabilities of MALDI-MS for high-throughput analysis of drug abuse. ResultsThe immuno-MALDI-MS chip was successfully prepared by coating an aluminum chip with antibody-conjugated boronic acid-modified gold nanoparticles. Ketamine, a frequently abused illicit drug, served as the proof of concept for this study. The immuno-MALDI-MS chip was employed to selectively enrich ketamine in human urine samples, facilitating direct MALDI-MS analysis with the addition of α-CHCA matrix solution. The challenge of detecting abused drugs, exacerbated by interfering peaks in the low m/z region from salts and small molecules in human urine samples, was successfully overcome. The developed method exhibited a wide linear range of 10–5000 ng/mL with a limit of detection of 3.3 ng/mL for ketamine. Notably, the proposed method enabled high-throughput screening and accurate confirmation of ketamine concentrations in suspects' urine samples within few minutes, requiring a minimal sample volume of 1 μL. The obtained data were in complete agreement with the previous GC/MS analysis. SignificanceA straightforward, cost-effective and sensitive method for the selective enrichment and absolute quantification of abused drugs was developed using a homemade immuno-MALDI-MS chip integrated with MALDI-MS analysis. This method combines the advantages of immunoassay and mass spectrometry, offering both speed and accuracy. The reported method for the quantification of ketamine in human urine offers a practical approach and has the potential to analyze emerging new psychoactive substances in the future.

Efficient conversion of corn stover to glucose using alkaline DBU synergized glycerol-based deep eutectic solvent under mild conditions

Efficient pretreatment is crucial for the high-value and effective conversion of lignocellulose. However, the current glycerol-based deep eutectic solvent (DES-Gly) pretreatment method requires high reaction temperatures, considerable solvent usage, and yields low conversion efficiency. In this study, we investigated the pretreatment of corn stover with 1,8-diazobicyclic [5.4.0] undeca-7-ene (DBU) synergized with DES-Gly, which significantly enhances the glucose yield from corn stover. The strong synergistic effect of DBU and DES-Gly effectively removes lignin and substantially increases glucose yield. Under optimal conditions, 95.27 % glucose conversion could be achieved, even with the addition of only 2 FPU/mL of cellulase. The physicochemical properties of the DES-Gly solution and pretreated corn stover were analyzed using FTIR, XRD, SEM, TGA, and 1 H NMR characterization techniques. In addition, DES-Gly and DBU synergy mechanisms are further explored. Our work provides a mild, efficient and low-cost DES-Gly-based pretreatment method, introducing a new way for the catalytic conversion of lignocellulose to sugar production.

Development of a magnetic separation method for rapid isolation and enrichment of bacteria in raw pork using chitosan functionalized magnetic Fe3O4@MIL-100(Fe) composites.

In this study, a pretreatment method based on a magnetic capture probe for the rapid isolation and enrichment of bacteria from raw pork was developed. The chitosan immobilized Fe3O4@MIL-100(Fe) was prepared as a capture probe for total bacterial counts through the electrostatic interaction of positively charged chitosan and the negatively charged substances on the surface of bacteria. The interference of matrix in pork samples on this method was studied and removed by differential centrifugation. The results showed the capture probe had a great selectivity binding and magnetic separation properties for the tested six common bacteria in pork. Under the optimal conditions, the capture efficiency of the bacteria (105 CFU mL-1) from pork surface samples was all above 90%. The capture efficiency of the bacteria in a homogenate system was greatly decreased due to the interference of sarcoplasmic protein and myofibrillar protein in pork. The matrix effect was mitigated by a differential centrifugation method, and the capture efficiency of all six bacteria was >80%. The developed magnetic separation method took 40min and showed good isolation and enrichment properties of bacteria. Thus, the proposed method is expected to provide a simple, convenient, and time-saving pretreatment method for the detection of total bacterial counts in pork.

Development of oriented microbial consortium-based compound enzyme strengthens food waste hydrolysis and antibiotic resistance genes removal: Deciphering of performance, metabolic pathways and microbial communities

Enzymatic hydrolysis has been considered as an eco-friendly pretreatment method for enhancing bioconversion process of food waste (FW). However, existing commercial enzymes and microbial monomer-based compound enzymes (MME) have the issues of uneven distribution of enzymatic activity and low matching degree with the components of FW, leading to low efficiency with enzymatic hydrolysis and removal of antibiotic resistance genes (ARGs). This study used FW as the substrate, under the co-culture system, produced a microbial consortium-based compound enzymes (MCE) with oriented and well-matching degree for FW hydrolysis and ARGs removal, of which the performance, metabolic pathways and microbial communities were also investigated in depth. Results showed that the best performance for ARGs was achieved by the MCE prepared by mixing 1:5 of Aspergillus oryzae and Aspergillus niger after 12 days fermentation. The highest soluble chemical oxygen demand (SCOD) concentration and ARGs removal could respectively reach 83.90 ± 1.67 g/L and 45.95% after MCE pretreatment. The analysis of metabolic pathways revealed that 1:5 MCE pretreatment strengthened the catalytic activity of carbohydrate-active enzymes, increased the abundances of genes involved in cellulose and starch degradation, polysaccharide synthesis, ATP binding cassette (ABC) transporters and global regulation, while decreased the abundances of genes involved in mating pair formation system, two-component regulatory systems and quorum sensing, thereby enhanced FW hydrolysis and restrained ARGs dissemination. Microbial community analysis further indicated that the 1:5 MCE pretreatment promoted growth, metabolism and richness of functional microbes, while inhibited the host microbes of ARGs. It is expected that this study can provide useful insights into understanding the fate of ARGs in food waste during MCE pretreatment process.

The Efficiency of Chemical and Electrochemical Coagulation Methods for Pretreatment of Wastewater from Underground Coal Gasification

This article compares chemical coagulation with electrocoagulation, two popular methods for the primary treatment of wastewater generated in the process of underground coal gasification (UCG). The primary aim was to determine which method is more effective in the removal of cyanide and sulphide ions, metals and metalloids, as well as organic compounds. In both cases, experiments were conducted in batch 1 dm3 reactors and using iron ions. Four types of coagulants were tested during the chemical coagulation study: FeCl2, FeSO4, Fe2(SO4)3, and FeCl3. In the electrocoagulation experiments, pure iron Armco steel was used to manufacture the sacrificial iron anode. Both processes were tested under a wide range of operating conditions (pH, time, Fe dose) to determine their maximum efficiency for treating UCG wastewater. It was found that, through electrocoagulation, a dose as low as 60 mg Fe/dm3 leads to >60% cyanide reduction and >98% sulphide removal efficiency, while for chemical coagulation, even a dose of 307 mg Fe/dm3 did not achieve more than 24% cyanide ion removal. Moreover, industrial chemical coagulants, especially when used in very high doses, can be a substantial source of cross-contamination with trace elements.

Life cycle assessment of tomato biomass residue anaerobic digestion preceded by ethanol-based organosolv and choline chloride-based deep eutectic solvent

Anaerobic digestion (AD) of lignocellulosic wastes (LW) has garnered substantial interest because of its notable energy and nutrient recovery, along with its potential for reducing greenhouse gas emissions. However, the LW is resistant to degradation, and its hydrolysis typically requires harsh conditions, hence the need for a pretreatment. Conducting a life cycle assessment (LCA) to evaluate the pretreatment of LW is an effective way to assess the environmental impacts associated with various pretreatment methods. This work evaluates and compares three scenarios for handling lignified tomato green waste (TGW), generated in the Greater of Agadir in Morocco, in terms of their environmental impacts and energy demand, using the LCA approach, performed with OpenLCA software. To achieve this aim, the impact of these scenarios on 11 indicators is studied. The analyzed management options include a base case scenario S0 where TGW undergoes a direct anaerobic digestion (AD), organosolv pretreatment of TGW followed by AD of the free-lignin fraction (S1), and choline chloride-based deep eutectic solvent (DES) delignification followed by AD of the free-lignin fraction (S2). The data used for the analysis comes from the Tamelast landfill, laboratory tests, literature, CML-IA baseline and Monte Carlo simulation calculations. The results obtained showed that the introduction of pretreatments in S1 and S2 mitigates significantly the environmental impact in different categories compared to S0. Scenario S2, with its enhanced recovery processes, shows the highest positive environmental contributions, despite its reliance on additional external electricity. S1 and S0 both respect energy circularity. Through this study, it has been demonstrated that chemical pretreatment of LW is energy, water and solvent-intensive and requires a large investment. It opens up perspectives for further works on pretreatment using natural DES technology, its development and its applications in the delignification of ligneous biomass on an industrial scale.

Effective catalytic conversion of cellulose pyrolysis into D-Allose via Al1-Fe5 nano-catalysts

This research has made significant advancements in the field of high-value bio-oil production, specifically focusing on the synthesis of the rare sugar D-Allose. Notably, synthesizing D-Allose through cellulose pyrolysis has long been challenging due to its high synthetic difficulty, which has limited related studies. By employing a one-pot synthesis approach using Alx-Fey nano-catalysts prepared through a unique cellulose pretreatment method, this experiment successfully achieved efficient generation of D-Allose during rapid pyrolysis. Systematic experimentation demonstrated that at 330 °C with the Al1-Fe5 nano-catalyst, the yield of D-Allose from cellulose pyrolysis reached an impressive 50.69 %, accompanied by a detection of 14.35 % furfural in the bio-oil. This breakthrough not only significantly contributes to the high-value utilization of bio-oil but also provides robust support for further development in this area. Simultaneously, the success of this research extends beyond high-value bio-oil utilization and makes a substantial impact on both the scientific community and industry.

Determination of leaf nitrogen content in apple and jujube by near-infrared spectroscopy

The nitrogen content of apple leaves and jujube leaves is an important index to judge the growth and development of apple trees and jujube trees to a certain extent. The prediction performance of the two samples was compared between different models for leaf nitrogen content, respectively. The near-infrared absorption spectra of 287 apple leaf samples and 192 jujube leaf samples were collected. After eliminating the outliers by Mahalanobis distance method, the remaining spectral data were processed by six different preprocessing methods. BP neural network (BP), random forest regression (RF), least partial squares (PLS), K-Nearest Neighbor (KNN), and support vector regression (SVR) were compared to establish prediction models of nitrogen content in apple leaves and jujube leaves. The results showed that the determination coefficient (R2), root mean square error (RMSE) and residual prediction deviation (RPD) of the models established by different combined pretreatment methods were compared among the five methods. Compared with the performance of the other four models, the modeling method of SG + SD + CARS + RF was suitable for the prediction of nitrogen content in apple leaves, and its modeling set R2 was 0.85408, RMSE was 0.082188, and RPD was 2.5864. The validation set R2 is 0.75527, RMSE is 0.099028, RPD is 2.1956. The modeling method of FD + CARS + PLS was suitable for the prediction of nitrogen content in jujube leaves. The modeling set R2 was 0.7954, RMSE was 0.14558, and RPD was 2.4264; the validation set R2 is 0.81348, RMSE is 0.089217, and RPD is 2.4552.In the prediction modeling of apple leaf nitrogen content in the characteristic band, the model quality of RF was better than the other four prediction models. The model quality of PLS in predictive modeling of nitrogen content of jujube leaves in characteristic bands is superior to the other four predictive models, These results provide a reference for the use of near-infrared spectroscopy to determine whether apple trees and jujube trees are deficient in nutrients.

Lactic acid bacteria‐fermented Chlamydomonas reinhardtii as an innovative ingredient to produce microalgae‐enriched steamed bread

AbstractBackground and ObjectivesChlamydomonas reinhardtii (C. reinhardtii) is recognized as a sustainable source of high‐quality protein. This study aimed to assess the potential application of C. reinhardtii for producing microalgae‐fortified steamed bread. To reduce the inherent green color and volatile compounds of the microalgae, lactic acid bacteria (LAB) fermentation was applied as a pretreatment method for C. reinhardtii. Subsequently, both unfermented (unFC) and fermented C. reinhardtii (FC) were added to steamed bread formulations (4%, 8%, 12%, and 16% wheat flour substitution).FindingsThe results showed that the incorporation of unFC into steamed bread had a dose‐dependent negative impact on the dough fermentation performance and the quality of steamed bread, including volume, texture, and sensory attributes, rendering the steamed bread unacceptable. Fermentation altered the amino acid profile of C. reinhardtii, caused the color to shift from green to red (a*, −14.7 vs. 7.0), and reduced unpleasant volatile components. Further, fermentation reduced the negative impact of microalgae incorporation, especially at substitution levels of 4% and 8%, which manifested as an increased dough fermentation volume and improved bread volume with reduced crumb firmness of the steamed bread. However, in sensory analysis, the steamed bread that contained 4% FC had an overall acceptability similar to the control sample.ConclusionsMicroalgae‐enriched steamed bread could be produced by incorporating up to 4% FC to improve its nutritional profiles while maintaining overall sensory acceptability by the consumers.Significance and NoveltyLAB fermentation of C. reinhardtii is a feasible strategy to address the sensory and structural challenges that hinder the incorporation of algae into food products.

Hyperspectral Imaging Combined with Deep Transfer Learning to Evaluate Flavonoids Content in Ginkgo biloba Leaves.

Ginkgo biloba is a famous economic tree. Ginkgo leaves have been utilized as raw materials for medicines and health products due to their rich active ingredient composition, especially flavonoids. Since the routine measurement of total flavones is time-consuming and destructive, rapid, non-destructive detection of total flavones in ginkgo leaves is of significant importance to producers and consumers. Hyperspectral imaging technology is a rapid and non-destructive technique for determining the total flavonoid content. In this study, we discuss five modeling methods, and three spectral preprocessing methods are discussed. Bayesian Ridge (BR) and multiplicative scatter correction (MCS) were selected as the best model and the best pretreatment method, respectively. The spectral prediction results based on the BR + MCS treatment were very accurate (RTest2 = 0.87; RMSETest = 1.03 mg/g), showing a high correlation with the analytical measurements. In addition, we also found that the more and deeper the leaf cracks, the higher the flavonoid content, which helps to evaluate leaf quality more quickly and easily. In short, hyperspectral imaging is an effective technique for rapid and accurate determination of total flavonoids in ginkgo leaves and has great potential for developing an online quality detection system for ginkgo leaves.

An eco-friendly one-step pretreatment method for the synthesis of electroless coating on magnesium alloy

Using a one-step pretreatment process, this study synthesized an environmentally friendly and cost-effective electroless Ni-W-P coating on the AZ31 magnesium alloy. Aqueous iron (II) sulfate treatment was used as a replacement for conventional pretreatment in the electroless coating on magnesium alloy. Using ammonia solution in the plating bath results in micro-pits in the coating, and cracks appear on the surface after a certain time of deposition. The deposition rate of the coatings was around 10 and 7 μmh−1 from plating baths with and without ammonia, respectively. Coatings from baths without ammonia (T2), on the other hand, have no pits and can develop thick coatings, whereas coatings from baths with ammonia (T1) can only form deposits up to 10 μm thick. The atomic structure of both coatings exhibits a mixture of microcrystalline and amorphous phases. The coatings T1 and T2 showed an adhesion strength of 6 ± 0.24 and 8.1 ± 0.15 MPa, respectively. Both T1 and T2 coatings have significantly higher corrosion resistance and microhardness than the base alloy.