High Pressure Homogenization Pretreatment Research Articles

Effect of high-pressure homogenization pretreatment on gelation behavior and physicochemical, rheological and structural properties of sesame protein isolate with glucono-δ-lactone

This study investigated the gelation of sesame protein isolate induced by high-pressure homogenization (HPH) with glucono-δ-lactone (GDL) acidification, focusing on the effect of pressures on gelation behavior and physicochemical, rheological and microstructural properties of the resulting gels. The HPH significantly affected the acidification kinetic parameters such as Vmax, Tmax, T5, and T4.5. The maximum Vmax (0.062 pH units/min) value was determined in the sample treated with 100 MPa, and T4.5 was decreased by 30 min with HPH at 50 and 100 MPa pressures. The particle size of sesame protein decreased with the homogenization pressure increased, and this played a role in the formation of lower particle size aggregates after gelation. The highest water holding capacity (69.02%) and gel strength (7.9 g) were reached with a pressure at 100 and 150 MPa, respectively. While a significant increase in the whiteness index of gels was observed by increasing pressure up to 100 MPa, the highest total color difference (ΔE) was detected at 50 MPa. The G′ value of the samples tended to increase with gelation time and with the high pressure applied, indicating a significant improvement in the elasticity of the gels. All gel samples exhibit shear-thinning behavior. Hydrophobic interactions were dominant in the gel samples, and the highest value (8.28 mg/g) was determined in the sample prehomogenized at 100 MPa. This study revealed that the gelation properties of sesame protein induced by GDL can be improved with HPH and that 100 MPa pressure application is ideal.

Enhancing Cutin Extraction Efficiency from Industrially Derived Tomato Processing Residues by High-Pressure Homogenization.

This study primarily aimed to enhance the extraction of cutin from industrial tomato peel residues. Initially, the conventional extraction process was optimized using response surface methodology (RSM). Subsequently, high-pressure homogenization (HPH) was introduced to improve extraction efficiency and sustainability. The optimization process focused on determining the optimal conditions for conventional extraction via chemical hydrolysis, including temperature (100-130 °C), time (15-120 min), and NaOH concentration (1-3%). The optimized conditions, determined as 130 °C, 120 min, and 3% NaOH solution, yielded a maximum cutin extraction of 32.5%. Furthermore, the results indicated that applying HPH pre-treatment to tomato peels before alkaline hydrolysis significantly increased the cutin extraction yield, reaching 46.1%. This represents an approximately 42% increase compared to the conventional process. Importantly, HPH pre-treatment enabled cutin extraction under milder conditions using a 2% NaOH solution, reducing NaOH usage by 33%, while still achieving a substantial cutin yield of 45.6%. FT-IR analysis confirmed that cutin obtained via both conventional and HPH-assisted extraction exhibited similar chemical structures, indicating that the main chemical groups and structure of cutin remained unaltered by HPH treatment. Furthermore, cutin extracts from both conventional and HPH-assisted extraction demonstrated thermal stability up to approximately 200 °C, with less than 5% weight loss according to TGA analysis. These findings underscore the potential of HPH technology to significantly enhance cutin extraction yield from tomato peel residues while utilizing milder chemical hydrolysis conditions, thereby promoting a more sustainable and efficient cutin extraction process.

Effects of high-pressure homogenization and ultrasound on the composition, structure, and physicochemical properties of proteins extracted from Nannochloropsis Oceania

This study examined the effects of high-pressure homogenization (HPH) and ultrasonication pre-treatment on the structural and physicochemical properties of proteins extracted from defatted Nannochloropsis Oceania biomass (DNOB). HPH treatment was found to enhance the solubility of protein extracted from DNOB compared to ultrasound, where samples pretreated with three passes (3P) of HPH exhibited lower solubility than two passes (2P). The morphology of extracted samples was visualized by scanning electron microscopy, which HPH pre-treatment, especially with more passes, were able to breakdown DNOB into fragments. Alternatively, more holes were displayed on the surface of the extracts pretreated with ultrasound especially when higher amplitude applied. The particle size of extracts from HPH3P (129.5 µm) significant dropped from HPH2P (314.25 µm), where samples pretreated with ultrasound at 20 % amplitude (US20) also decreased in particle size compared to 40 % amplitude (US40), from 115.25 µm to 78.22 µm. Protein flexibility of DNOB extracts were enhanced by both HPH2P and HPH3P but decreased for ultrasound samples. β-sheets were found to be the most abundant protein secondary structure for all samples, where samples treated with HPH3P contained the highest percentage of β-sheets (72 %) than control, HPH2P, ultrasonication at 20 and 40 % amplitude (52–62 %). The high percentage of β-sheets found in HPH3P sample also contributed to its outstanding emulsifying properties which stood out among all, especially at concentrations over 1 mg/ml. Results obtained from this study helped to direct the application of DNOB extracts as functional food ingredient for future food innovation.

Evaluation of high-pressure homogenization as a pretreatment for the extraction and drying of 6-gingerol from ginger

6-Gingerol is the major biologically active component found in the ginger rhizome, and this study investigated the effect of high-pressure homogenization pretreatment on the recovery of 6-gingerol.

Conversion of Materials and Energy in Anaerobic Digestion of Sewage Sludge with High-Pressure Homogenization Pretreatment

High pressure homogenization (HPH) pretreatment can improve sludge anaerobic digestion; however, the relationship among the material, energy conversion, and gas production efficiency was unclear under different operating conditions in sludge anaerobic digestion by HPH pretreatment. In this study, the performance of HPH pretreatment before sludge anaerobic digestion was investigated, and the relationship among the material, energy conversion, and gas production efficiency was explored. HPH pretreatment induced organic solubilization, and a maximum soluble chemical oxygen demand (SCOD)/total chemical oxygen demand (TCOD) of about 30% was achieved. Results showed that HPH pretreatment significantly improved the biogas production of sludge anaerobic digestion; the maximum increase in CH4 yield was 57%; and the anaerobic digestion period was shortened by about 10 days. The ratio of CH4 yield increment to volatile dissolved solids (VDS) increment was 0.21 mL/mg. The CH4 yield increment of 1 L/g volatile solid (VS) required a specific energy of 0.10 MJ/kg total solid (TS) by increasing the pressure with one cycle and 0.72 MJ/kg TS by increasing the cycle at 60 MPa. The minimum additive energy consumption of HPH pretreatment was 125 J/mL CH4 yield increment at 20 MPa with one cycle. Considering CH4 yield improvement and energy conservation, HPH pretreatment should maintain a pressure of no more than 60 MPa in one cycle. This study provides a theoretical reference for the practical application of HPH pretreatment in anaerobic digestion. HPH holds promise as a potential strategy for sewage sludge pretreatment to produce CH4 in anaerobic digestion.

Structural and Physical Properties of Alginate Pretreated by High-Pressure Homogenization.

To develop a high-efficient extraction method, we investigated the use of high-pressure homogenization (HPH) as a novel pretreatment technology for the extraction of sodium alginate (SA) from Laminaria japonica. After the single-factor experiment, the results demonstrated that under the conditions of 100 MPa HPH pressure, 4 cycles, pH 6.0, and 0.5% EDTA for 3.0 h, the optimized extraction yield of HPH reached 34%. To further clarify the effect on the structural properties of HPH-extracted SA, we conducted comprehensive analysis using SEM, FTIR, MRS, NMR, XRD, TGA, and a T-AOC assay. Our findings revealed that HPH pretreatment significantly disrupted the structure of L. japonica cells and reduced their crystallinity to 76.27%. Furthermore, the antioxidant activity of HPH-extracted SA reached 0.02942 mgVceq∙mg-1. Therefore, the HPH pretreatment method is a potential strategy for the extraction of alginate.

Kinetics of high pressure homogenization assisted protein extraction from Chlorella pyrenoidosa

Protein extraction kinetics from microalga Chlorella pyrenoidosa by applying High Pressure Homogenization pretreatment was studied. Untreated and treated (400–800 bar, 1 and 4 passes) aqueous microalgal suspensions were incubated at 20–40 °C for up to 24 h. A four-pass treatment at 800 bar caused maximization of carbohydrate (103 mg carbohydrates/g dry biomass immediately after treatment) and protein recovery (382.0 mg proteins/g dry biomass after extraction at 40 °C for 24 h). Protein characteristic extraction time was significantly dependent on pretreatment conditions and extraction temperature (5.16 h for untreated sample at 20 °C vs. 1.34 h for 800 bar/4 passes treated biomass at 40 °C). A combination of a two-hour ethanolic extraction at 60 °C prior to a six-hour aqueous extraction from biomass treated at 800 bar/4 passes maximized chlorophyll separation (16.3 mg chlorophylls/g dry biomass) and led to aqueous extracts of high protein content (764.7 mg proteins/g dry extract).

Impact of high-pressure homogenization pretreatment on recovery of curcumin from turmeric by different combinations of extraction and drying methods

This study reports the effect of different extraction and drying techniques in the recovery of curcumin, where the impact of the pre-treatment step on turmeric rhizome using high-pressure homogenization (HPH) was evaluated. Soxhlet extraction (SE) and ultrasound-assisted extraction (UAE) followed by drying (oven drying, vacuum drying, and freeze drying) were applied to HPH-treated and control (non-HPH) samples. The HPH treatment condition of 100 MPa for 10 cycles demonstrated the lowest particle sizes in the turmeric suspensions and the highest curcumin content in the aqueous supernatant. It was also found that HPH treatment increased the release of curcumin from the freeze-dried turmeric extracts obtained from SE (+76.2%) and UAE (+57.5%). Besides, freeze drying was the best drying method demonstrating higher antioxidant activity of extracts than other thermal drying methods. The total phenolic content was increased by about 65.5% upon HPH treatment on turmeric extract obtained from UAE followed by vacuum drying.

Using high-pressure homogenization as a potential method to pretreat soybean protein isolate: Effect on conformation changes and rheological properties of its acid-induced gel

This study evaluated the conformational changes and rheological properties of acid-induced gels of insoluble soybean protein isolate (SPI) pretreated with high-pressure homogenization (HPH) under different pressure and cycles. Results showed that HPH pretreatment destroyed the spatial structure of the insoluble SPI, significantly decreased the particle size of the SPI dispersion, and increased the SH content. Through the characterization of its acid-induced gelation product, the best ability to withstand small strains (< 3%) of gel was found in a single HPH cycle under 100 MPa. The SPI gels with a relatively compact structure transformed from strain stiffening to strain softening with the strain increased, and it provided satisfactory stability to withstand large-amplitude oscillatory shear in three-time HPH cycles under 100 MPa. Meanwhile, SPI gels exhibited a more chaos spatial topology network after HPH pretreatment through fractal analysis, and the gels eventually exhibited “soft gel” and shear-thinning behavior with HPH pretreatment. This provides an evidence for the beneficial effect of HPH on the structural homogenization and subsequent gel formation stability of protein gels, and explores its potential applications in the food industry.

Combining high pressure homogenization with free nitrous acid pretreatment to improve anaerobic digestion of sewage sludge.

Single pretreatment of sewage sludge, either physical, chemical or biological, has its own drawbacks in term of poor sanitization, energy intensity and high operational and capital cost. To tackle these drawbacks, combined high pressure homogenization (HPH) and free nitrous acid (FNA) pretreatment for sludge solubilization and further biodegradation in anaerobic digestion was investigated. Synergistic effect of combined HPH (40MPa) and FNA (2.49mg/L) pretreatment (HPH-FNA) for improving anaerobic digestion was evaluated, and its effect on archaeal and bacterial community structure was analyzed. Compared with single HPH and FNA pretreatments, HPH-FNA pretreatment efficiently solubilized wasted activated sludge (WAS), subsequently improved anaerobic digestion. Cumulative biogas production from sewage sludge pretreated with HPH-FNA was 154%, 108% and 284% more than that with single pretreatment of FNA, HPH and raw sludge, respectively. In addition, volumetric biogas production of combined pretreatment system (815ml) was more than the sum from single pretreatment (710ml). Methane content in biogas for raw sludge, FNA, HPH and HPH-FNA pretreated sludge was 45%, 51%, 55% and 65%, respectively. Illumina MiSeq sequencing analysis revealed that HPH-FNA pretreatment promoted bacterial growth of phyla Bacteroidetes, Firmicutes and Synergistetes and archaeal genera Methanospirillum and Methanosaeta. Overall, combined HPH-FNA pretreatment of sewage sludge, prior to anaerobic digestion, is an environmentally-friendly and potentially economic technology.

Cellulose Isolation from Tomato Pomace Pretreated by High-Pressure Homogenization.

This work proposes a biorefinery approach for the utilization of agri-food residues, such as tomato pomace (TP), through combining chemical hydrolysis with high-pressure homogenization (HPH), aiming to achieve the isolation of cellulose with tailored morphological properties from underused lignocellulose feedstocks, along with the valorization of the value-added compounds contained in the biomass. Cellulose was isolated from TP using sequential chemical hydrolysis in combination with mechanical pretreatment through HPH. The chemical and structural features of cellulose isolated from TP pretreated by HPH were compared with cellulose isolated from untreated TP through light scattering for particle size distribution, optical and scanning electron microscopy, and Fourier-transform infrared spectroscopy (FT-IR) analysis. HPH pretreatment (80 MPa, 10 passes) not only promoted a slight increase in the yield of cellulose extraction (+9%) but contributed to directly obtaining defibrillated cellulose particles, characterized by smaller irregular domains containing elongated needle-like fibers. Moreover, the selected mild chemical process produced side streams rich in bioactive molecules, evaluated in terms of total phenols and reducing activity. The liquors recovered from acid hydrolysis of TP exhibited a higher biological activity than those obtained through a conventional extraction (80% v/v acetone, 25 °C, 24 h at 180 rpm).

Biostimulants obtained after pilot-scale high-pressure homogenization of Scenedesmus sp. grown in pig manure

Microalgae are becoming an important source of high-value products such as biostimulants, biopesticides, and other low-value products such as biofertilizers or aquafeed (fatty acids and carotenoids), among others. However, extracting the biomolecules contained in the microalgae cells is difficult due to the structure and composition of the microalgal cell wall. To overcome this difficulty, mechanical cell disruption methods, such as high-pressure homogenization (HPH), can be applied to facilitate the extraction of the compounds of interest.This work focuses on optimizing the extraction of biostimulants from microalgae biomass and obtaining amino acid concentrates that can be used in several applications. The research aims to study the effect of HPH pretreatment on the production of these different bioproducts using Scenedesmus sp. biomass grown in pig sludge as the raw material.For each product, the HPH pretreatment of the wet biomass must be optimized to select the optimal conditions and the number of passes. Soft treatment of the wet biomass at 200 bar is sufficient to observe a 10% increase in the germination index (GI) of watercress seeds, while greater treatment intensities reduce the GI with respect to the untreated biomass, possibly because this increases the concentration of the molecules responsible for the bioactivity, thus causing a toxic effect on the seeds. In the case of the amino acid concentrates, better results were obtained at 600 bar, achieving a hydrolysis level of 72.9%. Lastly, the concentrations of the phenolic compounds and the salicylic acid, related with enhanced biostimulant activity, were determined using spectrophotometric methods and High-Performance Liquid Chromatography- diode array (HPLC), respectively.

Anaerobic digestion of sewage sludge pretreated by high pressure homogenization using expanded granular sludge blanket reactor: Feasibility, operation optimization and microbial community

Biogas production via anaerobic digestion from sewage sludge have been investigated in different reactors. However, the efficient conversion of sewage sludge into biogas via continuous operational reactor with short retention time, have been overlooked. Considering the liquid-like property of sewage sludge pretreated by high pressure homogenization (HPH), in this study, the biogas production from HPH-pretreated sewage sludge was investigated in an expanded granular sludge blanket (EGSB) reactor for 219 d. Under optimized hydraulic retention time (HRT) of 6 d, upflow velocity of 4 m/h and organic loading rate (OLR) of 1.66 kg total chemical oxygen demand (TCOD)/(m3·d), the raw sludge was digested with a biogas production, methane content in biogas, TCOD and volatile solid (VS) removal of 215 mL/(gTCOD)·d, 52 %, 43 % and 35 %, respectively. After sludge HPH pretreatment, the HRT was shortened to 5 d due to the sludge disintegration of 24 % and enhanced growth of acetolastic Methanosaeta and hydrogenotrophic Methanolinea, subsequently, the biogas production, methane content in biogas, TCOD and VS removal increased to 240 mL/(gTCOD)·d, 57 %, and 58 % and 43 %, respectively. Abundance of dominant bacterial phylum Chloroflexi and archaeal genera Methanosaeta significantly increased for the improvement of organic biodegradation and methane production, respectively, reflecting the successful EGSB operation. Due to the good performances of EGSB reactor for the anaerobic digestion of HPH-pretreated sewage sludge, the combined HPH-pretreatment and EGSB reactor is promising to be applied in sustainable wastewater treatment plants.

Consequences of dynamic high-pressure homogenization pretreatment on the physicochemical and functional characteristics of citric acid-treated whey protein isolate

This study investigated the physicochemical and functional characteristics of citric acid (CA)-treated whey protein isolate (WPI) by dynamic high-pressure homogenization (DHPH) at different pressure levels (0, 25, 50, 75, and 100 MPa, 3 cycles). The number of macromolecular polymers increased in CA-treated WPI with DHPH at 0–100 MPa by the analysis of molecular size distributions. DHPH can reduce the particle size of WPI and CA-treated WPI. Additionally, the content of free sulfhydryl groups and surface hydrophobicity of WPI and CA-treated WPI increased after DHPH treatment (p < 0.05). Also, DHPH promoted gel formation in the CA-treated WPI, with the gel hardness increased by 43.66% after DPHP pretreatment at 100 MPa (p < 0.05). Meanwhile, after DPHP pretreatment at 100 MPa, emulsifying activity index (EAI) of CA-treated WPI and WPI increased by 13.15% and 27.36%, respectively (p < 0.05). Thus, DHPH pretreatment could enhance the degree of crosslinking of the CA-treated WPI and improve its gel and emulsifying properties, broaden the application of WPI in food processing.

Physicochemical and emulsifying properties of orange fibers stabilized oil-in-water emulsions

The present work aimed to evaluate the physical and techno-functional property and microstructure of freeze-dried orange pulp and peel powders modified by high-pressure homogenization (HPH) treatment, and their emulsifying properties of oil-in-water emulsions treated with HPH. For orange pulp and peel powders, HPH pre-treatment was found to significantly reduce bulk density and increase the water and oil holding capacity (P < 0.05) of orange pulp and peel powders, and the particles appeared to have flake-like shape. When orange-pulp and peel dispersions were subjected to HPH treatment, all samples showed significant decreases in particle size and increases in ζ-potential (P < 0.05), and could maintain higher stability with extended storage time. Furthermore, Confocal Laser Scanning Microscopy (CLSM) also revealed that emulsion destabilization occurred with increased storage time due to oil-droplet aggregation and coalescence. The results indicated that emulsion stability was improved by HPH treatments, probably due to a steric or electrostatic repulsion against flocculation or coalescence of oil droplets, and orange fibers, particularly orange pulp are suitable feedstock as natural emulsifiers.

Beneficial effects of high-pressure homogenization on the dispersion stability of aqueous hydrolysate from Mytilus edulis

Owing to the formation of aggregation and gelation during storage, certain proteins and peptides exhibit limited applications in aqueous protein food products. The purpose of this study was to investigate the influence of homogenization and xanthan gum addition on the dispersion stability of Mytilus edulis hydrolysate (PHM). High-pressure homogenization (HPH) at 360 and 40 bar in the first and second values, respectively, and adding xanthan gum at a concentration of 1 mg/mL showed significantly improvement on the stability of the PHM solution. PHM-xanthan gum solutions (PHMX) showed the highest polypeptide precipitation rate and turbidity retention rate compared with those of PHM. Moreover, the centrifugal precipitation rate of PHMX without HPH was higher than that of homogeneous PHMX. After HPH treatment at 400 bar, the percentage of smaller particles in PHM and PHMX was increased, the aqueous system became more uniform, and the fluorescence intensity reached its maximum. HPH pre-treatment improved the polypeptide dispersion stability and turbidity retention rate of PHM and PHMX and reduced the fluorescence intensity. The interactions of xanthan gum and polypeptide render the network microstructure more uniform under the conditions of homogenization, thus improving the dispersion stability of PHMX solutions. Therefore, under the premise of adding xanthan gum, HPH can better enhance the dispersion stability of the polypeptide in PHM.

Enhancement of high pressure homogenization pretreatment on biogas production from sewage sludge: a review

Enhancement of high pressure homogenization pretreatment on biogas production from sewage sludge: a review

Structure and characterization of laccase-crosslinked α-lactalbumin: Impacts of high pressure homogenization pretreatment

The effect of high pressure homogenization (HPH) pretreatments (0, 20, 40, 60, 80, 100, and 120 MPa for 4 cycles) on structure, physicochemical properties and functionality of laccase-treated α-lactalbumin (α-LA) was examined in this experimental study. Mass spectrometry and gel filtration chromatography revealed that monomers of laccase-treated α-LA decreased remarkably, and oligomers (dimers, trimers and tetramers) and polymers were formed with homogenization pressures ranging from 0 to 120 MPa. The HPH treatment exposed more α-LA tyrosine residues, which were further catalyzed by laccase to form dityrosine. Additionally, fourier transform infrared spectroscopy indicated that there were lower α-helix and higher random coil contents in laccase-treated α-LA with increasing homogenization pressure. The HPH pretreatment increased the emulsifying and gel properties of laccase-treated α-LA. Thus, the HPH pretreatment enhanced the crosslinking degree of laccase-treated α-LA as well as its functionality.

Contribution of solid and liquid fractions of sewage sludge pretreated by high pressure homogenization to biogas production

High pressure homogenization (HPH) pretreatment can effectively enhance anaerobic sludge digestion. In order to understand the corresponding mechanisms, different homogenization pressures were applied on sewage sludge, and solid and liquid fractions were separately digested to clarify contribution of solid and liquid fractions to biogas production. Results showed that the methane was mainly produced from solid fraction, and methane yield was increased with the increase of pretreatment pressure. The biogas and methane production from sludge (digested without solid–liquid separation) was 17% and 45% higher than the sum of that from solid and liquid fractions (digested separately) under a pressure of 40 MPa, respectively. This indicated that the sludge liquid fraction synergistically improved the biodegradation of sludge solids. The improvement of anaerobic digestion was attributed to organic release by sludge disintegration, sludge disruption and further increase of particle surface area. The methane production was linear with effectiveness of HPH pretreatment.

High-Pressure Homogenization Pre-Treatment Improved Functional Properties of Oyster Protein Isolate Hydrolysates.

The effects of HPH (high-pressure homogenization) pre-treatment on the functional properties of OPIH (oyster protein isolates hydrolysates) were studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles, solubility, particle size distribution, zeta potential, surface hydrophobicity, emulsifying activity index and microstructure of emulsions were analyzed. Results indicated that HPH pre-treatment increased the accessibility of OPI to trypsin hydrolysis, resulting in decease in particle size, increase in solubility, absolute zeta potential, surface hydrophobicity and emulsifying activity index. In addition, HPH pre-treated OPIH emulsions became more uniform and the particle size of droplets decreased. These results revealed that HPH pre-treatment has the potential to modify the functional properties of OPIH.