Pretreated Samples Research Articles

Calcium peroxide induced mechanical disintegration in acidic environment for efficient biogas and biopolymer generation from paper mill sludge

The proposed research envisioned to improve the accessibility of organics and hydrolysis of paper mill waste activated sludge for polyhydroxybutyrate production and anaerobic digestion. In order to fill this research gap an exploration has been made by adding lower dosage of calcium peroxide at acidic pH for the removal of exopolymeric substances thereby improving the disintegration efficacy. The results indicate that the calcium peroxide dosage of 0.06 g/g SS at pH 5 was optimum for floc fragmentation. The influence of floc fragmented sludge on disintegration by disperser shows the solubilization and solid decrement of 18.8% and 12.4% at the specific energy input of 4729.24 kJ/kg total solid. The impact of pretreated supernatant on polyhydroxybutyrate accumulation shows the maximum polyhydroxybutyrate content of 85.03 % while utilizing 60% (v/v) of pretreated sludge supernatant as a carbon source at 42 h. Subsequently, the settled sludge was directed towards an anaerobic biodegradability assay and found about 167 mL/g of chemical oxygen demand of biogas generation, which is higher than the crude sample (52 mL/g of chemical oxygen demand). The higher solubilization in pretreated sample reveals the easier accessibility of substrate by the microorganisms, thereby enhances bioenergy and valued product generation.

Alkaline pretreatment of a polymetallic sulfide (Fe-Pb-Mn) ore containing silver increases the efficiency of cyanidation by decreasing elemental sulfur content and by exposing sulfide surfaces

Polymetallic sulfide ores are often not amenable to cyanide leaching due to the presence of several elements and minerals capable of interfering with this process. Thus, various strategies, such as chemical pretreatments, are often studied to improve the efficiency of cyanidation. Beyond the results of such strategies, it is important to understand the changes occurring on the mineral samples during these pretreatments. Herein, an alkaline pretreatment was applied to a silver concentrate (∼8 kg Ag/t) composed of polymetallic sulfides (Fe-Pb-Mn), which increased the silver extraction during subsequent cyanidation from 40% to 80% and decreased the cyanide consumption in half (from approximately 60 to 30 kg NaCN/t). X-ray diffraction (XRD) and ICP-MS indicated that the pretreatment could remove significant amounts of elemental sulfur, which is a known cyanicidal agent. The dissolution of significant amounts of sulfur was confirmed by chemical analysis, which also demonstrated that the dissolution of iron, lead, manganese, and silver were negligible during pretreatment. At surface level, X-ray photoelectron spectroscopy (XPS) demonstrated that the pretreatment exposes fresh sulfide surfaces (e. g. pyrite). In addition, the XPS spectra indicated that the pretreatment facilitated the exposure of clean mineral surfaces. The presence of cleaner surfaces suggested a more uniform and less hindered diffusion of leaching agents through the mineral. Indeed, fitting the extraction data to the shrinking core model showed that pretreated samples featured a nearly ideal diffusion-controlled process, while in the case of untreated samples this fitting was less adequate. During cyanidation of both untreated and pretreated samples, lead build-up was detected on the surface (readsorption), which suggested that this phenomenon does not affect the efficiency of a leaching process. This study highlights the importance of combining bulk analytical methods with surface-sensitive techniques to obtain a more complete understanding of leaching processes.

Pretreatment with ChOH/Urea under mild conditions for the efficient deconstruction of poplar cell wall

In this study, DES consisting of Choline hydroxide (ChOH) and Urea (Ur) was used to pretreat poplar under mild conditions (60 ℃). The 72 h saccharification efficiency of the pretreated samples for 10 min was significantly improved (69.97 %), which amounted to a 2.4-fold increase in sugar yield over the raw material (29.89 %). The remarkable enhancement could be correlated to the topochemical and morphological changes occurring in poplar cell walls, including the removal of lignin and hemicelluloses, decreased crystallinity and microstructural disruption. Noteworthy, X-ray diffraction analysis showed that cellulose I underwent a crystallographic transformation from cellulose I to cellulose II during DES pretreatment. Our study demonstrated that ChOH/Ur pretreatment was quite effective in deconstructing poplar cell walls and increasing the enzymatic hydrolysis efficiency of cellulose under mild conditions.

Goat milk casein and protease sonication as a strategy to improve the proteolysis and functional properties of hydrolysates

This study investigated the impact of ultrasound (US) pretreatment on Alcalase and goat milk casein (GMC) to enhance GMC proteolysis. We assess the degree of hydrolysis (DH), TCA-soluble protein concentration, protein solubility and in vitro antioxidant activity. US pretreatment of Alcalase (40 °C/60 min) or GMC (60 °C/30 min) increased the relative enzyme activity by up to 15.6 and 18.1%, respectively. Hydrolysis using US pretreated samples increased the DH (up to 37%), and TCA-soluble protein concentration (up to 73%). This led to higher solubility (up to 37% at pH 4.0) and antioxidant activity (up to 37% in ABTS assay) of the hydrolysates after 180 min of reaction (p < 0.05). Our findings suggest Alcalase sonication as the best strategy to improve GMC proteolysis and the multifunctional properties of hydrolysates, due to the lower volume to be processed and performance similar to that observed after substrate sonication.

Optimization of rAAV capture step purification using SO3 monolith chromatography.

Adeno-associated virus (AAV) vectors are crucial tools for gene therapy applications. As AAVs are administered in vivo, stringent purity requirements must be met, necessitating the development of various downstream processing strategies in accordance with regulatory guidelines. In this context, we focus on the non-affinity serotype-independent recombinant AAV (rAAV) capture step, which involves the use of Convective Interaction Media (CIM) cation-exchange SO3 monoliths. We analyzed differentially pretreated viral samples obtained from the Sf9 cell line and applied these samples to the capture SO3 chromatography step. We conducted screening experiments using CIM SO3 0.05mL monolithic 96-well plates with buffers of varying pH, sodium chloride concentrations, and the inclusion of poloxamer 188, aiming to select the optimal binding mobile phase. Dynamic binding capacity was defined for different pretreatments and the optimal conditions were subsequently retested using the industrial purification CIMmultus line. The results demonstrated a high overall vector recovery (51%) and a significant reduction in impurities (99.98% for protein reduction and 99.25% for DNA reduction) using the selected capture step parameters, thereby confirming the successful optimization of the rAAV capture step in the downstream process using monoliths.

Drying characteristics of Cistanche deserticola with different pretreatment and degradation mechanism of phenylethanoid glycosides during drying

Cistanche deserticola (C. deserticola), a medicine food homology plant, has been widely cultivated, produced and processed, and has high commodity value. Due to the degradation of active components during the processing of C. deserticola caused by enzymatic browning, the aim of this paper is to evaluate the drying characteristics of C. deserticola with different pretreatments including steam, hot water and microwave treatment. Furthermore, the degradation mechanism of phenylethanoid glycoside (PhGs) by enzymatic reaction and thermal degradation during drying was revealed with a new perspective. The results showed that microwave pretreatment promoted the drying characteristics. The degradation rates of echinacoside (ECH) and acteoside (ACT) in untreated samples were 0.30–0.75 and 0.54–2.45 mg mL−1 h−1, respectively, which were significantly higher than those in thermal simulation systems and microwave pretreated sample systems. Interestingly, the degradation activation energy of PhGs in untreated samples was negative, indicating that the enzymatic reaction was a non-elementary reaction, and the pathway of the reaction was speculated.

Drying Kinetics, Effective Moisture Diffusivity, and Activation Energy of Osmotic Pretreated Hot-Air-Dried Paneer Cubes

Paneer is a heat-acid-coagulated dairy product, and it has a very low shelf life due to its higher moisture content of about more than 50% (w.b). Drying is the best option to reduce moisture, but it takes time and affects the nature of the product. Here, osmotic dehydration (OD) is applied as pretreatment prior to drying to preserve the color and textural changes and reduce the drying time. Commercial NaCl was chosen as osmotic agent. The paneer samples were taken as ( 2 cm × 2 cm × 2 cm ) cubes and pretreated with NaCl, viz., 6%, 12%, 22% w / v , and surface treatment. The pretreated paneer was dried at 50, 55, and 60°C in a hot-air dryer with constant air velocity of 0.25 m/s. The equilibrium moisture content level was higher in osmotic treated samples compared to the control sample with range between 12.46 and 16.64% (w.b). The osmotic pretreated sample had shortened drying time compared to the control sample. Effective moisture diffusivity and activation energy were calculated, and the osmotic pretreatment impacted positively on it. The drying parameters were fitted with models and found that the Midilli model was ( R 2 &gt; 0.99 ) best fit. The osmotic pretreated samples at 50°C drying temperature show ( P ≤ 0.01 ) better results in color, texture, and sensory profile of dried paneer, while pretreatment is not effective at 55 and 60°C drying temperatures. Except for the carbohydrate content, osmotic pretreated samples retain more fat and protein after the drying process. As a result, it can be concluded that osmotic pretreatment reduces the drying time and retains color, texture, and nutritional characteristics of dried paneer, especially at 50°C drying temperature.

A study of chloride pretreatment methods for enhancing strength of mortar by recycling Municipal Solid Waste Incineration (MSWI) bottom ash

This study explores four different ways (tap water, deionized water, sodium chloride, and seawater) as the pretreatment methods of Municipal Solid Waste Incineration (MSWI) bottom ash used in mortar. After incorporation of the bottom ash as partial replacement of fine aggregate, the mixtures were evaluated for compressive strength, heat of hydration, chloride content and shrinkage performance. The results reveal that all pretreated samples have comparable compressive strength at early age (day-7) and higher compressive strength at later age (day-120). Meanwhile, the pretreatment in tap water and deionized water can slightly reduce the chloride content, whereas the other two pretreatment methods induce extra chloride ions into the mixtures. The correlation between the chloride content and the peak temperature indicates the acceleration effect of chloride ions during hydration. In addition, all the specimens with pretreated MSWI aggregates have higher shrinkage regardless of pretreatment methods.

Molar masses and molar mass distributions of commercial regenerated cellulose materials and softwood dissolving pulp determined by SEC/MALLS

The molar masses and molar mass distributions of three commercial regenerated cellulose samples, viscose rayon, Tencel, and Bemliese (or cuprammonium nonwoven), have been determined by dissolution in 8% (w/w) lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) and subsequent size-exclusion chromatography with multi-angle laser-light scattering detection (SEC/MALLS). Before dissolution in LiCl/DMAc, the regenerated cellulose samples were pretreated by the following three methods: (1) soaking in ethylene diamine (EDA) and subsequent solvent exchange to N,N-dimethylacetamide (DMAc) through methanol, (2) soaking in water and subsequent solvent exchange to DMAc through ethanol, and (3) soaking in water and subsequent solvent exchange to tert-butyl alcohol through ethanol and freeze dying. The pretreated samples were dissolved in 8% (w/w) LiCl/DMAc by stirring the cellulose/LiCl/DMAc mixtures for 1–3 weeks followed by dilution to 1% (w/v) LiCl/DMAc for SEC/MALLS analysis. The EDA- and water-pretreated samples gave almost the same SEC-elution pattens and molar mass plots, resulting in similar number- and mass-average molar masses. However, the freeze-dried samples gave 10%‒20% lower mass recovery ratios than those obtained for the EDA- or water-pretreated samples, probably because of incomplete dissolution of the freeze-dried samples in 8% (w/w) LiCl/DMAc. The average mass-average degree of polymerization values of viscose rayon, Tencel, and Bemliese were 340, 530, and 880, respectively. The slopes of the conformation plots were 0.58–0.62, showing that all of the molecules in the three regenerated cellulose samples were dissolved in 1% (w/v) LiCl/DMAc, forming linear random-coil conformations.Graphical abstract

Cu3Si formed by vacuum evaporation deposition enhances hydrogenation of silicon tetrachloride

The efficient conversion of SiCl4 to SiHCl3 still presents considerable challenges for the Siemens process. The enhancement of solid-solid interaction between catalyst and silicon particles in hydrogenation of SiCl4 is viewed as a top priority. In this study, CuCl catalyst and silicon particles mixture heated at the vacuumized tube bomb reactor is found to be an effective pretreatment strategy for obtaining excellent catalytic performance as much as 21.2% under the optimum conditions. The vacuum evaporation deposition is favorable for the deposition uniformly of gaseous CuCl on the surfaces of silicon particles and the formation of Cu3Si. The moderate temperature and time of the vacuum evaporation deposition pretreatment will promote the growth of copper compounds and shorten the induction period of SiCl4 hydrogenation reaction. When CuCl and free copper of the pretreated sample are dissolved by NH4OH, the SiCl4 conversion still maintains 19.8%. Cu3Si is employed as the active phase expresses good catalytic performance where the conversion of SiCl4 is positively correlated with the content of Cu3Si.

Bioenergy production from pretreated rice straw in Nigeria: An analysis of novel three-stage anaerobic digestion for hydrogen and methane co-generation

The response to Nigeria's energy inadequacies and waste management issues is projected in this research to be achieved with hydrogen and methane co-produced from pretreated (PT) rice straw (RS) in a three-stage digestion process. This study also demonstrated a novel pretreatment (PTM) agent to improve biological energy recovery from RS. The objectives were accomplished using acidogenic and methanogenic procedures in batch, semi-continuous and continuous systems after pretreating RS with chemical/potash extract (PE) followed by a biological agent. At the same time, the energy assessments were done using data from the laboratory study and the literature. The research findings indicated that at the acidogenesis stage, specific hydrogen yield was insignificant when chemical agents and PE were employed alone. However, the daily H2 production increased when the PT RS residues were enzymatically hydrolysed with NaOH-PT (114 NmL H2 g−1 TS d−1) and PE-PT (103 NmL H2 g−1 TS d−1) RS substrates having the highest values at steady states and raw RS producing the least (30 NmL H2 g−1 TS d−1). In the methanogenesis phase, chemical/ PE PTM followed by enzymatic hydrolysis of RS improved the daily specific methane production by 18%, 31.7% and 41.5% for HCl, PE and NaOH-PT RS residues. The methane production efficiency was 80% for NaOH, 75% for PE, and 68% for HCl RS PT samples, while the raw RS was 48%. The total output energy expressed in electricity and thermal production using combined cooling, heat, and power (CCHP) showed that NaOH and PE-PT RS digesters gave the highest electricity (892.43 and 852.00 KWhelect. tonne-1 TS) and thermal (1194.10 and 1140 KWhtherm. tonne-1 TS) yield respectively. Similarly, the cooling fluid in KWhcool produced per tonne of TS RS was 835.57, 798.00 and 741.66 for NaOH, PE and HCl PT RS samples. Finally, whereas the Firmicutes, especially the Clostridium, Ruminococcus and Thermoanaerobacterium, were the dominant microbial community in acidogenic digestates, the Euryarchaeota typified by Methanobacterium, Methanosarcina and Methanosaeta were the principal phyla for most methanogenic reactors.

Effect of forging pretreatment on the microstructures and mechanical properties of the Al-Cu-Li alloy

The 2195 Al-Cu-Li alloy is widely utilized in the aerospace industry due to its lightweight nature and high strength. Consequently, gaining a comprehensive understanding of techniques to enhance its microstructural and mechanical properties is crucial for the consistent production of reliable and high-strength aerospace components. In this investigation, a pristine 2195 industrial ingot was subject to three distinct forging pretreatments: PT1, which involved a direct three upsetting and three stretching (3U3S) process; PT2, which combined double stage homogenization (DH) with 3U3S; and PT3, which involved DH along with six upsetting and six stretching (6U6S). Subsequent warm deformation and T8 aging treatment were applied to the pretreated forgings. The microstructure evolution during the processes and the final mechanical properties in three orthogonal dimensions were examined. The findings revealed that the combination of DH and multi-dimensional forging (MDF) facilitated the dissolution of non-equilibrium phases to a greater extent. Consequently, the main strengthening phase transformed from the T1 + δ` phase observed in PT1 to the denser T1 + little θ` phase observed in PT2 and PT3 after T8 aging treatment. Notably, the tensile strength and yield strength of PT2 and PT3 specimens increased by 20–30 MPa in all three directions. Moreover, the MDF process accelerated the recrystallization behavior from PT1 to PT3, resulting in a gradual reduction in the average grain size of the pretreated samples from 356 µm to 186 µm. Following warm forging and T8 aging, the grains exhibited a finer and equiaxed structure. Additionally, the coarse phase was identified as the primary source of transgranular cracking. The coarse phases within the matrix became more homogeneous and finer from PT1 to PT3, with a gradual decrease in their area fraction. On the fracture surfaces, the aggregation of coarse phases diminished. Consequently, the elongation in the z-direction improved, and the elongation anisotropy and standard deviation decreased in all three directions for PT3 specimens. The findings presented in this study provide valuable insights into the high-performance manufacturing of Al-Cu-Li alloys.

Conventional and microwave-assisted acid pretreatment of tea waste powder: analysis of functional groups using FTIR.

Tea waste powder (TWP) is one of the potential biomass waste to recover valuable chemicals and materials. The prime objective of this work is to investigate the role of acid pretreatment on TWP. Diluted acids (HCl, H3PO4, CH3COOH, and H2SO4) were used to soak the TWP to understand the role of acids on bond cleavage and chemicals formation. One gram of TWP was soaked in 100 mL of diluted acids for 24 h. The soaked samples were further subjected to a hot air oven (temperature: 80 °C, duration: 6 h), orbital shaking (shaking speed: 80-100 rpm, duration: 6 h), and microwave irradiation (microwave power: 100 W, duration: 10 min) to understand the synergistic effects of acids and mode of exposure. The pretreated solid samples and liquid samples were analyzed using FTIR to understand the presence of functional groups. The mass loss of TWP after treatment significantly varied with the type of acid and exposure mode used. In the orbital shaker, the mass loss was varied in the following order: H2SO4 (36%) > CH3COOH (32%) > H3PO4 (22%) > HCl (15%). In hot air oven, high mass loss was observed compared to orbital shaking [HCl (48%) > CH3COOH (37%) > H2SO4 (35%) > H3PO4 (33%)]. The mass loss in microwave irradiation is lower (19 to 25%) with all acids compared to orbital shaking. In the solid samples, O-H stretching, C-H stretching, C=O stretching, C=C stretching, -C-O-, and -C-OH- functional groups were noticed. Similarly, C=O and C=C peaks and C-O and -C-OH peaks were noticed in liquid samples. Interestingly, microwave irradiation showed promising results in 10 min of pretreatment, whereas orbital shaking and hot air oven pretreatments require 6 h to achieve the same result.

Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp.

To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper's ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low- cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity.

Effect of laser textured patterns on the interfacial characteristics and mechanical properties of 6061Al/GFRTP joints via hot-pressing

Joining metal and glass fiber reinforced thermoplastic composite (GFRTP) is advantageous for obtaining a lightweight structure. In this study, a hot-pressing joining of 6061 aluminum alloy (6061Al) and GFRTP was realized, and three textured patterns on the 6061Al surface were prepared by a nanosecond laser to enhance the bonding strength of two materials. The influence of laser textured patterns on the interfacial characteristics and mechanical properties of 6061Al/GFRTP joints was systematically investigated. The results implied that the surface roughness of 6061Al was increased and a better wettability of molten GFRTP was obtained after laser texturing. Besides, the strain distribution of laser textured joints was more uniform than the pretreated sample during tensile–shear loading. Furthermore, a transformation of fracture mode from the interface failure to the mixed failure occurred. Therefore, the mechanical properties of joints were significantly improved after laser texturing, which provided a solution method for joining metal to polymer.

Investigating the influence of plastic waste oils and acetone blends on diesel engine combustion, pollutants, morphological and size particles: Dehalogenation and catalytic pyrolysis of plastic waste

Most research into the treats of plastic wastes have concentrated mainly on single-exposure pathways or products. These practices fail to acknowledge that the complications of carbon particles from engines are produced not only by diesel but by any plastic oils due to the vast amount of contaminants. With the potential to significantly weaken the impact of contaminants, the present study investigates the effects of dehalogenation and catalytic pyrolysis on plastic waste, as well as the risks associated with plastic oil blends on diesel engine. Different types of washing were conducted to effectively dehalogenate plastic waste. After pretreatment, odor compounds were analyzed using GC–MS. Subsequently, various types of pretreated plastic samples underwent catalytic pyrolysis with a 5:1 ratio of HDPE to Al2O3·2SiO2·2H2O. Differences in physico-chemical properties and hydrocarbon compounds of oils were determined. Experiments were performed using different fuel blends in a diesel engine under steady-state conditions, and their effects on combustion, emissions, morphology, and size particles were analyzed. The results show that sample B exhibited a lower toxicity level of 1,3-butadiene compared to other samples, while acetone and terpenes represented the second and third-highest emission levels in flakes, respectively. Sample C started to degrade at low temperatures (<300 °C) due to carbon addition from ethyl acetate solvent into the tertiary carbon chain of the flakes. DAP3 fuel achieved a higher reaction due to its degree of unsaturation and lower viscosity, resulting in the formation of smaller fuel droplets at high injection pressure and heat release rate (HRR). Higher emission levels were observed by DAP1 and D100, exceeding the Euro 5/6 standard limits. However, DAP3 fuel resulted in an average reduction of ∼17.14% and 21.86% in CO and smoke emissions, respectively, accompanied by a slight decrease in NOx and HC levels. Conversely, there were inconsistencies in the emission results observed with DAP2. Compared to D100, both DAP1 and DAP2 exhibited a significant accumulation and coarse particles in the PM10 forms at a peak of ∼83 nm. Whereas the DAP3 showed a smaller mobility Dp with a low nucleation particle peak, which was prone to absorb the unburned HC soot and later change to accumulation mode particles.

Alkali assisted water treatment of aluminum promoting the growth of hydrated oxide film for energy conservation

Aluminum anodizing process consumes a lot of energy for ions migration in solid phase. Commonly, the aluminum foil is treated by boiling water to form crystalline γ'-Al2O3 for reducing the energy consumption. In order to improve water treatment, the alkaline buffer solution was used for promoting the growth of hydrated oxide film and contributed to formation of crystalline alumina. As a result, the obtained samples consumed 12.08% less energy during anodizing process compared with that of water treated samples. The hydrated oxide film was detected by means of morphological and electrochemical analysis, which indicated the alkaline treatment promoted generation of hydrated oxide film as well as formed dense anodic oxide film after anodizing. Furthermore, the pretreated samples owned denser anodic oxide film verified by X-ray diffraction and electrochemical analysis, which implied less production of alumina on the same electrical performance. Therefore, the alkaline solution treatment of aluminum/hydrated oxide film has a good prospect for getting rid of the limitation of high energy consumption in electrolytic capacitors industry.

Microwaves as sustainable approach for artificial ripening of date fruit cv. Khupra to reduce fruit waste

Date fruit ripening depends upon various factors, including climate, environment, soil type, air and humidity. Due to these factors, some cultivars of date fruit are unable to ripen on the trees and deteriorates. Thus a significant quantity of date fruit is wasted every year, which impose significant concerns on food security. Therefore, this study investigated the effect of microwave pre-treatment for ripening of dates. For this purpose, date fruits cv. Khupra at the Khalal stage were pretreated at different microwave power level (30, 50 and 80 W) and time (30, 40 and 50 s) combinations for the improved microstructural and compositional characteristics. Afterwards, the treated samples were stored at relative humidity (50 %) and temperature (50 °C). The data indicated that microwave pretreated dates retained better quality in comparison to sun dried samples. The microwave treated fruits exhibited TSS contents up to 60.3 ± 0.09 °Brix, a whiteness index of up to 15.4, and an antioxidant capacity of up to 78 ± 0.04 %. Texture profile analysis also revealed that the sundried fruits have more hardness of 724 ± 0.01 (g-force) compared to microwave pretreated samples which was supported by the Scanning electron microscopy analysis. Moreover, FTIR spectra readings indicated the presence of various dietary fiber components such as cellulose, lignin, hemicellulose, fructose, glucose, arabinose, glactomannans, pectins, and organic acids retained in microwave pretreated dates. In short, Microwave pretreatment can potentially replace the conventional sun drying method for production of superior quality ripened dates.

Effect of Preliminary Treatment by Pulsed Electric Fields and Blanching on the Quality of Fried Sweet Potato Chips.

The effects of pulsed electric fields (PEF) and blanching pretreatments on frying kinetics, oil content, color, texture, acrylamide (AA) content, and microstructure have been investigated in this paper. The total PEF pretreatment duration was tPEF = 0.2 s with an intensity of E = 1 kV/cm; blanching was studied at 85 °C for 5 min. The results demonstrated that pretreatment significantly reduced the moisture ratio and oil content by 25% and 40.33%, respectively. The total color change ΔE value of the pretreated samples was lower than that of the untreated samples. In addition, pretreatment increased the hardness of the sample after frying, and the AA content in the fried samples pretreated with PEF + blanching was reduced by approximately 46.10% (638 μg/kg). Finally, fried sweet potato chips obtained by the combined pretreatment exhibited a smoother and flatter cross-sectional microstructure.

Application of Central Composite Design and Superimposition Approach for Optimization of Drying Parameters of Pretreated Cassava Flour.

The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85-74.14 °C) and drying time (3.96-11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production.