Effect Of Different Pretreatment Methods Research Articles

Effect of different pretreatment methods on the stability of pumpkin seed milk and potential mechanism

Pumpkin seeds represent a valuable source of plant protein and can be utilized in the production of plant-based milks. This study aims to investigate the effects of different pretreatment techniques on the stability of Pumpkin Seed Milk (PSM) and explore potential mechanisms. Raw pumpkin seeds underwent pretreatment through roasting, microwaving, and steaming to prepare PSM. Physiochemical attributes such as composition, storage stability, and particle size of PSM were evaluated. Results indicate that stability significantly improved at roasting temperatures of 160 °C, with the smallest particle size (305 ± 40 nm) and highest stability coefficient (0.710 ± 0.002) observed. Nutrient content in PSM remained largely unaffected at 160 °C. Protein oxidation levels, infrared, and fluorescence spectra analysis revealed that higher temperatures exacerbated the oxidation of pumpkin seed emulsion. Overall, roasting raw pumpkin seeds at 160 °C is suggested to enhance PSM quality while preserving nutrient content.

Effect of Different Pretreatment Methods on Drying Characteristics and Quality of Wolfberry (Lycium barbarum) by Radio Frequency-Hot Air Combined Segmented Drying

Effect of Different Pretreatment Methods on Drying Characteristics and Quality of Wolfberry (Lycium barbarum) by Radio Frequency-Hot Air Combined Segmented Drying

Comparison of different preparation methods for oxygen isotope determination of phosphate in mammal tooth enamel

AbstractWe tested several sample pre-treatment protocols for the study of oxygen isotope ratios in the phosphate phase of mammalian enamel of ten different fossil samples. We investigated the effect of different pre-treatment methods and the duration of the hydrogen fluoride treatment on enamel samples from skeletal phosphate with known δ18O values. The samples had been measured previously, so we could compare the ratios measured in our laboratory with the previous values to choose the best chemical preparation procedure. Four pre-soaking methods and two different time intervals of 2 mol dm−3 hydrogen fluoride treatment were compared during our experiments. In our experimental conditions, the distilled water wash and the 6 h of soaking in hydrogen fluoride gave the closest results to the expected δ-values. The steps of the tested preparation processes were repeated at least three times on each sample, so the reproducibility of the process could be also investigated.

Comparison of Different Surface Pre-Treatment on Mild Steel for Cobalt-Nickel-Iron Electroplating

Electroplating is extensively practiced in the industry to fabricate corrosion-protective coatings for steel in large-scale production. Mild steel easily rusts at ambient temperature thus surface pre-treatment is mandatory to eliminate rust and superficial scale from the steel. Pre-treatment ensures that the steel surface is free from contaminants, which may interfere with the surface quality of the protective coating. This research is done to investigate the effect of different pre-treatment methods on the surface quality of mild steel rings and cobalt-nickel-iron coated mild steel rings. These surfaces were achieved by polishing the ring and subjected to alkaline degreasing, followed by immersion in sulfuric acid or sodium chloride at 10 vol % concentration and different immersion times (50 s, 55 s, and 60 s). Direct electroplating was applied to fabricate the cobalt-nickel-iron coating. The surface morphology of metal substrate and coating after electroplating were tested by scanning electron microscope (SEM), energy dispersive X-Ray (EDS), Vickers hardness, and surface roughness tests. Both types of pre-treatments provided lower surface roughness on the metal substrate and resulted in full coatings without voids formation. The results showed that pre-treatment using sulfuric acid exhibited higher hardness and a smoother coating surface. Agglomerates and cracking were observed on the surface coating treated with sodium chloride.

Production of Sugar from Cassava Peel using Different Chemical Pre-treatment

Cassava peel has been a notable agricultural waste material to researchers because of its potential to produce sugar, a valuable product in the food, agricultural, and cosmetic industries. The peels constitute lignin, hemicellulose, and cellulose, also known as lignocellulosic biomass. Cassava peels must undergo a pre-treatment method to separate the lignocellulosic material effectively. This study aims to investigate the optimal chemical pre-treatment methods and optimal pre-treatment concentration to produce sugar from cassava peel. Cassava peels were pre-treated with sodium hydroxide, sulphuric acid, and methanol with a catalyst (organosolv). Then, enzymatic hydrolysis was performed using cellulase to hydrolyze cellulose to glucose. The glucose yield is quantified using Dinitrosalicylic Acid Assay and a portable blood glucometer. The results showed that pre-treatment using sodium hydroxide at a concentration of 0.05 M at 121°C for 15 minutes gave the highest glucose yield of 4.53±1.20 mg/ml. Glucose produced from 0.05 M sulphuric acid (H2SO4) and 0.2 M organosolv sodium methoxide (MeOH+NaOAc) were 3.55±0.68 mg/ml and 3.29±0.93 mg/ml, respectively. Statistical analysis showed that the effect of different pre-treatment methods and pre-treatment concentrations had a significant glucose yield (P<0.05). Similarly, there was a significant difference (P<0.05) in the glucose yield under different pre-treatment concentrations. Further study on mechanical-assisted chemical pre-treatment methods is recommended.

Investigating the effect of different pre-treatment methods on Raman spectra recorded with different excitation wavelengths

Raman reference libraries can be used for identification of components in unknown samples as Raman spectroscopy offers fingerprint information of the measured samples. Since Raman libraries often contain many different and/or highly similar spectra, it is important that the spectra are a reliable fingerprint for each compound. However, Raman spectra are highly sensitive to the experimental conditions, and the Raman spectra will change in different conditions even though the same sample is measured. Raman data pre-treatment minimizes the differences between Raman spectra arising from different experimental conditions. In this study, different combinations of pre-treatment methods are used to quantify the effect of each pre-treatment step in minimizing the differences between Raman spectra of the same sample in different experimental conditions, e.g., different excitation wavelengths. These different pre-treatment processes are evaluated for six solvents. The spectra differences between spectra recorded with three excitation wavelengths (532 nm, 633 nm, and 830 nm) are evaluated by angular difference index and the influence on a classification model is tested.The angular difference index of each spectrum after every data pre-treatment step shows a decreasing behavior. It could be demonstrated that wavenumber calibration has the largest effect on the differences between the Raman spectra. However, ω4 correction doesn’t have a significate effect in this dataset. The classification results show that the prediction accuracy is improving by doing data pre-treatment. In the dataset obtained in 633 nm a lower amount of pre-treatment steps is needed but in the dataset 830 nm more pre-treatment steps are needed for a high accuracy. The result shows that the choice of an optimal pre-treatment method or combination of methods strongly influences the analysis results, but is far from straightforward, since it depends on the characteristics of the data set and the goal of data analysis.

The effect of different pretreatment methods on jujube juice and lactic acid bacteria-fermented jujube juice

To obtain optimal juice-making methods, three pretreatment methods were selected to evaluate their effects on the quality characteristics of jujube juices before and after lactic acid bacteria fermentation. As a result, significant differences between all detected indicators were observed in fermented and unfermented jujube juices following different pretreatment methods. Jujube juices pretreated with hot water soaking (HS) had better color and higher levels of total sugar, reducing sugar and free amino acids than those pretreated with boiling water steeping (BS) and steam steaming (SS). Remarkably, similar tendencies were also found in the corresponding fermented jujube juices. In contrast, higher levels of total acids were found in all-jujube juices pretreated with BS. After lactic acid bacteria fermentation, however, all of the fermented jujube juices pretreated by the HS method displayed the highest total acid levels. As the major volatile components, the total levels of acids in the HS treatment were also significantly higher than those in the other two pretreatments. Sensory evaluation revealed that the fermented jujube juices after BS treatments showed relatively high acceptability among the panelists. These findings demonstrated valuable direction in improving the product quality of fermented jujube juice.

Chemical and Structural Elucidation of Lignin and Cellulose Isolated Using DES from Bagasse Based on Alkaline and Hydrothermal Pretreatment.

The separation of cellulose, hemicellulose, and lignin components using deep eutectic solvent, which is a green solvent, to obtain corresponding chemicals can realize the effective separation and high-value utilization of these components at low cost. In this study, we used waste biomass sugarcane bagasse as the raw material, choline chloride as the hydrogen bond acceptor, and lactic acid as the hydrogen bond donor to synthesize a deep eutectic solvent of choline chloride/lactic acid (L-DES) and treated sugarcane bagasse pretreated by alkali or hydrothermal methods to separate cellulose, hemicellulose, and lignin. In addition, we comparatively studied the effect of different pretreatment methods on lignin removal by DES and found that the lignin removal rate by L-DES after alkaline pretreatment was significantly higher than that after hydrothermal pretreatment, and the mechanism of action causing this difference is discussed.

Comparative study of pretreatment on microwave drying of Gala apples (Malus pumila): Effect of blanching, electric field and freezing

Microwave drying is particularly recommended for thermosensitive products such as food products in order to preserve all their properties. During drying, some fruits tend to oxidize and brown, losing flavor and vitamins A and C. To reduce oxidation and preserve the quality of the dried product, a pretreatment by placing the fruit in an acid solution (citric or ascorbic) is recommended. On the other hand, blanching, freezing and electric field treatment alters the cell structure, allowing moisture to escape more easily and products to rehydrate more quickly.An experimental study was conducted to see the effect of different pretreatment methods on the kinetics and quality of microwave-dried apple samples. For drying kinetics, no significant effect is observed for the blanched and electric field treated samples. However, a reduction in drying time by a value of 14.6–20.3% is observed for frozen samples. In other hand, the best quality (lowest ΔE, lowest BI, and highest WI) is observed for the sample blanched in 5% citric acid at 60 °C. Finally, the effect of the different pretreatment methods on the quality of the surface structure of the dried samples was studied by scanning the surface structure using Scanning Electron Microscope (SEM).

Effect of different pre-treatment methods on gasification properties of grass biomass

The effect of different pre-treatments method on the gasification efficiency of grass biomass have not previously been evaluated. In this study, the effect of three different pre-treatment methods on gasification properties of grass biomass was investigated under CO2 conditions. The pre-treatment methods were dry torrefaction, wet torrefaction, and leaching (chemical). The results obtained showed that the heating values increased by 2,77% in the leached grass, 8,3% in the dry torrefied grass and 13,5% in the wet torrefied grass. However, the wet torrefaction had the highest reactivity index of 0,25 followed by dry torrefaction 0,182, then leaching 0,156. The effect of the different pre-treatment on activation energy showed that the activation energy of raw grass biomass was reduced from 161,7 kJ/mol to 141.5 kJ/mol for leached grass, 124.3 kJ/mol for dry torrefied and 86.97 kJ/mol for wet torrefied grass. These results show that wet torrefaction can improve gasification properties significantly when compared to dry torrefaction and leaching. The pore structure and pore volume effect of treated biomass was likely the predominant reason for the better char reactivity and conversion during gasification of wet torrefied sample. The research supplied an insight into the effect of different pre-treatment methods on grass biomass gasification.

Effect of different pretreatment methods on pore structure of activated carbon

The effects of pretreatment on the pore structure of activated carbon were studied by the methods of water washing, acid washing, alkali washing and a combination of acid washing and alkali washing. It can be known from experiments that water washing has a cleaning effect on activated carbon, while acid washing helps to open the micropores of activated carbon and improve its porosity. Sodium hydroxide solution has an etching effect on activated carbon, which can increase the porosity and average particle size of activated carbon. All the pretreatment methods in this article can improve the adsorption capacity of activated carbon for nitrogen, and the pretreatment by dilute hydrochloric acid is tested to be the most effective.

Cathodically Pretreated AuNPs-BDD Electrode for Detection of Hexavalent Chromium.

Hexavalent chromium (Cr (VI)) has strong oxidizing properties and can result in strong carcinogenic effects on human bodies. Therefore, it is necessary to detect hexavalent chromium sensitively and accurately. This article proposes the gold nanoparticles (AuNPs)–boron-doped diamond (BDD) electrode for the direct determination of chromium with a green and simple detection process by cathodic stripping voltammetry. Gold nanoparticles are used to enhance the detection performance toward Cr (VI). The effect of different pretreatment methods on electrode modification has been studied, and the detection parameters have been optimized. With the optimized conditions, the AuNPs–BDD electrode presents a good linear behavior in a Cr (VI) concentration range of 10 to 1000 μg/L. A low limit of detection of 1.19 μg/L is achieved. The detection process is simple and environmentally friendly. The sensor has been tested for the detection of Cr (VI) in a real water sample with satisfactory results, which indicates potential application of the AuNPs–BDD electrode for the sensitive and onsite detection of Cr (VI).

Effect of Different Pre-treatment Methods on the Quality, Sensory Properties and Storability of Bambara Groundnut Spread

ABSTRACT Spreads are made from plant oil and similar to margarine but with lower fat. In this study, Bambara spreads (BS) were made from pre-treated Bambara groundnuts using two different methods which are boiling (BBS) and fermentation (BFS). Spreads made from soaked Bambara and soyean were included as reference samples. Objective color determination, sensory evaluation, microbial profile and storability at refrigeration temperature were carried out using standard methods. The results obtained showed that spread made from boiled Bambara groundnut (BBS) is the most spreadable, organoleptically accepted by panelists and it has low fat and higher protein content. The coliform counts of the spread samples initially declined, then increased from day 6 of refrigerated storage; bacterial counts remained fairly static but also increased by day 6. Boiling may be the most suitable pre-treatment for Bambara groundnut spread in order to obtain a lower fat content spread that will result in great health benefits.

Effect of different pretreatment methods on structural carbohydrates of kenaf fiber

The application of pretreatment on lignocellulosic biomass is considered as a critical step to alter the recalcitrant structure of biomass especially in bioconversion process. Different pretreatment may result in different modification effects which is important to be rationally evaluated before adoption in order to achieve high yield of end products. Therefore, this study was done to evaluate the effect of different pretreatment methods on kenaf in terms of their chemical and physical properties. Kenaf was subjected to alkaline pretreatment using 4.42% sodium hydroxide operated at 100 °C for 1 hour and acid pretreatment using 0.1% nitric acid which was run at 60 °C for 12 hours. Through characterization study, higher structural carbohydrates were found in alkaline pretreated kenaf compared to acid pretreated kenaf with 73.4% and 70.3% respectively. The SEM, XRD and FTIR analysis showed the significant different of biomass structure before and after pretreatment. From this study, pretreatment process has been verified can improve the biomass compositions to be utilized for chemicals production by disrupt the structure and remove lignin which can be proven by the increasing in structural carbohydrates and decreasing in lignin yield from this characterization study.

Hydrogen production and energy recovery from macroalgae Saccharina japonica by different pretreatment methods

Algae biomass is considered as a promising energy feedstock, and bioenergy recovery from algae can be significantly enhanced by pretreatment. This study compared the effect of different pretreatment methods, including heat, acid, base, heat-acid and heat-base on macroalgae Saccharina japonica, and dark fermentation was conducted to achieve a couple generation of bioenergy and biomaterials. All the pretreatment could enhance the hydrogen production and energy recovery from macroalgae, and the combined pretreatment showed significant advantage in organics solubilization. Heat-base pretreated macroalgae achieved the highest hydrogen yield (17.5 mL/g TSadded), while highest total energy conversion efficiency (35.4%) was obtained from heat-acid pretreated macroalgae, which was 2.1- and 2.9-fold compared to the control test. Hydrogen production can be further enhanced by microbial acclimation to high Na+ concentration to relieve its inhibition.

Effect of different pretreatment methods on sesame husk-based activated carbon for supercapacitors with aqueous and organic electrolytes

Sesame husks have been explored as a novel precursor to prepare high-performance activated carbons through two pretreatment processes coupled with KOH activation. The optimal structure of as-prepared carbon, which consisted of numerous micropores, well-defined mesopores, high specific surface of 2772 m2/g and large total pore volume of 1.206 cm3/g, is obtained via pre-carbonization and KOH activation. When applied in supercapacitors, the as-prepared carbon-based electrode achieves high specific capacitance of 301 F/g and 155 F/g in 6 M KOH aqueous electrolyte and 1 M Et4NBF4/PC organic electrolyte, respectively. Moreover, it also shows superior cycling stability of 94.9% and 92.5% capacitance retention after 10,000 cycles in KOH and Et4NBF4/PC electrolyte. Hence, this work makes the sesame husks act as a novel carbonaceous precursor and makes the pre-carbonization combined with KOH activation as an effective method for electrode materials in supercapacitor applications.

Study on the prediction of soil heavy metal elements content based on visible near-infrared spectroscopy

The estimation of soils heavy metal content can reflect the impending surroundings of surface, which lays theoretical foundation for using covered vegetation to monitor environment and investigate resource. In this study, the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb in 44 soil samples were collected from Fufeng County, Yangling County and Wugong County, Shaanxi Province and were used as data sources. ASD FieldSpec HR (350–2500nm), and then the NOR, MSC and SNV of the reflectance were pretreated, the first deviation, second deviation and reflectance reciprocal logarithmic transformation were carried out. The optimal spectroscopy estimation model of nine heavy metal elements of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb was established by regression method. Comparing the diffuse reflectance characteristics of different heavy metal contents and the effect of different pretreatment methods on the establishment of soil heavy metal spectral inversion model. The results of chemical analysis show that there was a serious Hg pollution in the study area, and the Cd content was close to the critical value. The results show that: (1) NOR, MSC and SNV were adopted for the acquisition of visible near-infrared. Combining differential transformation can improve the information of heavy metal elements in the soil, and use the correlation band energy Significantly improve the stability and predictability of the model. (2) The modeling accuracy of the optimal model of nine heavy metal spectra of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb by PLSR method were 0.70, 0.79, 0.69, 0.81, 0.86, 0.58, 0.55, 0.99, 0.62. (3) The optimal estimation model of different elements using different treatment methods has better stability and higher precision, and can realize the rapid prediction of nine kinds of heavy metal elements in this region.

Study on Hyperspectral Characteristics and Estimation Model of Soil Mercury Content

In this study, the mercury content of 44 soil samples in Guan Zhong area of Shaanxi Province was used as the data source, and the reflectance spectrum of soil was obtained by ASD Field Spec HR (350-2500 nm) Comparing the reflection characteristics of different contents and the effect of different pre-treatment methods on the establishment of soil heavy metal spectral inversion model. The first order differential, second order differential and reflectance logarithmic transformations were carried out after the pre-treatment of NOR, MSC and SNV, and the sensitive bands of reflectance and mercury content in different mathematical transformations were selected. A hyperspectral estimation model is established by regression method. The results of chemical analysis show that there is a serious Hg pollution in the study area. The results show that: (1) the reflectivity decreases with the increase of mercury content, and the sensitive regions of mercury are located at 392 ~ 455nm, 923nm ~ 1040nm and 1806nm ~ 1969nm. (2) The combination of NOR, MSC and SNV transformations combined with differential transformations can improve the information of heavy metal elements in the soil, and the combination of high correlation band can improve the stability and prediction ability of the model. (3) The partial least squares regression model based on the logarithm of the original reflectance is better and the precision is higher, Rc2 = 0.9912, RMSEC = 0.665; Rv2 = 0.9506, RMSEP = 1.93, which can achieve the mercury content in this region Quick forecast.

Investigation of different pretreatment methods of Mediterranean-type ecosystem agricultural residues: characterisation of pretreatment products, high-solids enzymatic hydrolysis and bioethanol production

ABSTRACTAgricultural and agro-industrial lignocellulosic residues represent an important renewable resource for the production of fuels and chemicals towards a bio-based economy. Olive pruning, vineyard pruning and almond shells are important residues from agricultural activities in Mediterranean-type ecosystems. In the current work, bioethanol production from the above three types of agro-residues was studied, focusing on the effect of different pretreatment methods on enzymatic saccharrification efficiency of cellulose and production of second-generation bioethanol. Dilute acid, hydrothermal and steam explosion pretreatments were compared in order to remove hemicellulose and facilitate the subsequent enzymatic hydrolysis of the hemicellulose-deficient biomass to glucose. Enzymatic hydrolysis was performed in a free-fall mixing reactor enabling high solids loading of 23% w/w. This allowed hydrolysis of up to 67% of available cellulose in almond shells and close to 50% in olive pruning samples, and facilitated high ethanol production in the subsequent fermentation step; the highest ethanol concentrations achieved were 47.8 g/L for almond shells after steam explosion and 42 g/L for hydrothermally pretreated olive pruning residue.

Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes.

A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, 13C-solid-state NMR and morphological alterations after pretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while during hydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.