Pressure Homogenization Research Articles

Effect of roasting and high-pressure homogenization on texture, rheology, and microstructure of walnut yogurt

The effect of roasting and high-pressure homogenization on the quality of yogurt made from peeled walnut kernels was explored in this study. The G' and G'' values of yogurt made from walnuts roasted at high temperatures were reduced. The water-holding capacity and hardness of walnut yogurt were reduced to 47.73% and 24.22 g, respectively. Increasing the homogenization pressure reduced the particle size of the walnut yogurt to 20.50 μm. Homogenized walnut milk at 150 MPa increased the viscosity, hardness, and consistency of yogurt product from 11.71 to 16.74 Pa.s, from 30.01 to 71.63 g and from 283.17 to 455.24 g·s, respectively. The confocal laser scanning microscope observation demonstrated a reduction in the size of fat and protein micelles in the homogenized yogurt samples, resulting in a compact structure. This study will contribute valuable scientific insights to the advancement of plant-based yogurt quality.

Thermal and Modern, Non-Thermal Method Induction as a Factor of Modification of Inulin Hydrogel Properties.

The aim of the study was to compare the properties of inulin hydrogels obtained with different methods, e.g., the traditional-thermal method and new, non-thermal methods, used in food production, like ultrasonic, high-pressure homogenization (HPH), and high hydrostatic pressures (HHPs). It was found that each of the compared induction methods allowed for obtaining inulin hydrogels. However, the use of non-thermal induction methods allows for obtaining a gel structure faster than in the case of thermal induction. In addition, hydrogels obtained with new, non-thermal methods differ from gels obtained with thermal treatment. They were characterized by higher stability (from 1.7 percent point-of-stability parameters for HHP 150 MPa to 18.8 for HPH II cycles) and in most cases, by improved microrheological properties-lower solid-liquid balance toward the solid phase, increased elasticity and viscosity indexes, and lowering the flow index. The gels obtained with the new, non-thermal method were also characterized by a more delicate structure, including lower firmness (the differences between thermal and non-thermal inductions were from 0.73 N for HHP at 500 MPa to 2.39 N for HHP at 150 MPa) and spreadability (the differences between thermal and non-thermal inductions were from 7.60 Ns for HHP at 500 MPa to 15.08 Ns for HHP at 150 MPa). The color of ultrasound-induced inulin gels, regarding the HPH and HHP technique, was darker (the differences in the L* parameter between thermal and non-thermal inductions were from 1.92 for HHP at 500 MPa to 4.37 for 10 min ultrasounds) and with a lower a* color parameter (the differences in the a* parameter between thermal and non-thermal inductions were from 0.16 for HHP at 500 MPa to 0.39 for HPH II cycles) and b* color parameter (the differences in the b* parameter between thermal and non-thermal inductions were from 1.69 for 5 min ultrasounds to 2.68 for HPH II cycles). It was also found that among the compared induction methods, the high-pressure technique has the greatest potential for modifying the properties of the created inulin hydrogels. Thanks to its application, depending on the amount of applied pressure, it was possible to obtain gels with very different characteristics, both delicate (i.e., soft and spreadable), using HHP at 150 MPa, and hard, using HHP at 500 MPa, the closest in characteristics to gels induced with the thermal method. This may allow the properties of hydrogels to be matched to the characteristics of the food matrix being created.

Hybrid ANFIS-PSO algorithm for estimation of the characteristics of porous vacuum preloaded air bearings and comparison performance of the intelligent algorithm with the ANN

Air bearings are commonly used in systems requiring high precision, including semiconductor manufacturing, optical and electronic devices, and aerospace systems, and the usage of vacuum preloading and porous material provides a homogeneous pressure distribution on the bearing surface. The prediction of the characteristics of these air bearings, such as air film thickness and location, is crucial for designing and optimizing the performance of the systems. They exhibit highly nonlinear behavior and are challenging to accurately predict their characteristics using conventional analytical or numerical techniques. In this study, the characteristics of vacuum preloaded porous air bearings are estimated using a hybrid ANFIS-PSO predictor soft computing method with a certain pressure (410 kPa), vacuum (50.8 kPa), and with three different diameters (50, 75 and 90 mm). The usage of different algorithms in the characteristics and selection and design criteria of air bearing has been applied. Six different cases are simulated with different input and output parameters to predict the air film thickness and location of the air bearing. The location of the air bearing has been determined with two angle parameters, α, and β. The dataset required for training and testing the algorithm was obtained through experimental study. In the training and testing process, 40 and 20 datasets were used, respectively. Before the starting analysis, a sensitivity analysis was executed to find optimum PSO parameters such as the number of particles, acceleration coefficients, number of membership functions, and inertia weight. The proposed hybrid ANFIS-PSO method was compared with classical ANFIS and ANN, and it showed better performance and a more accurate solution to estimate the characteristics of vacuum preloaded porous air bearings in both training and testing phases with the R2 of 0.9958 and MSE value of 0.102. The maximum training performance of the ANFIS-PSO is better than ANFIS and ANN with the ratio of 6.8% and 8.5%, respectively. On the other hand, the maximum testing performance of the ANFIS-PSO algorithm is higher than ANFIS and ANN, with the ratio of 22.2% and 24.1%, respectively.

Formation of casein and maltodextrin conjugates using shear and their effect on the stability of total nutrient emulsion based on homogenization

This study aimed to explore the desirable properties of casein and maltodextrin conjugates (PPCs) with simultaneously increased stability of total nutrient emulsion (TNE). Molecular interaction, stability, rheology and microstructure were analyzed. The results exhibited that the D[4,3] of PPCs increased by 169.34% at the shear time of 12 min and zeta-potential increased to 22.56 mV when the shear time was 4 min. The fluorescence spectrum and Raman spectrum analysis showed that the maximum emission wavelength of casein shifted from 347 nm to 336 nm, and the I760 value showed a decreasing trend (0.93–0.41), indicating that the molecular structure of casein stretches and opens under the influence of the shear force, and the hydrophobic groups inside casein are released into the polar environment. Furthermore, the stability index TSI decreases from 1.3 to 0.7, the change rate of backscattered light decreases to 0.6%, and the local particle concentration decreases, suggesting that the stability of the TNE enhanced with the increase of homogenization pressure in a suitable range. Meanwhile, the droplet particles are obviously smaller and there is no cluster phenomenon. After 28 days of storage, the homogeneous pressure of 80 MPa and 100 MPa makes the TNE have smaller TBARS values. This work provides a comprehensive explanation for preparing TNE based on shear and homogenization treatments.

Structure, bioavailability and physicochemical properties of icariin-soymilk nanoparticle

Soymilk is a natural nanocarrier. However, the performance of flavonoid-soymilk nano-complex remains unclear. In this work, icariin-soymilk nano-complexes (ISNCs) were successfully fabricated and characterized. The effects of high-pressure homogenization (HPH) treatment on structure and physicochemical properties of soymilk and nano-complexes were investigated. HPH treatment could significantly improve the surface hydrophobicity and interfacial activity of soymilk. The soymilk with HPH treatment could significantly improve the water solubility (20 folds), thermal stability and bioavailability of icariin. The highest encapsulation efficiency (93.28 %), loading capacity (39.09 µg/mg), ζ-potentia (absolute value, 31.20 mV) and bioavailability (72.14 %) were observed in HSI-200 (200 bar of homogenization pressure). While HSI-500 (500 bar of homogenization pressure) showed the smallest particle size (183.73 nm). ISNCs showed a rougher surface and an irregular lamellar structure with large amount of fine particles by using Cryo-SEM, suggesting that icariin was encapsulated in soymilk. These data supplied a novel strategy to improve the performance of icariin in functional foods.

Influence of heat treatment before and/or after high-pressure homogenization on the structure and emulsification properties of soybean protein isolate

This study investigates the effects of heat treatment before high-pressure homogenization (HHPH) and heat treatment after high-pressure homogenization (HPHH) at different pressures (20, 60, and 100 MPa) on the structural and emulsification properties of soy protein isolate (SPI). The results indicate that HHPH treatment increases the surface hydrophobicity (H0) of the SPI, reduces β-fold and irregular curls, leading to the formation of soluble aggregates, increased adsorbed protein content, and subsequent improvements in emulsification activity index (EAI) and emulsion stability index (ESI). In contrast, the HPHH treatment promoted the exchange of SH/SS bonds between protein molecules and facilitated the interaction of basic peptides and β-subunits, leading to larger particle sizes of the soluble aggregates compared to the HHPH-treated samples. However, excessive aggregation in HPHH-treated aggregates leads to decreased H0 and adsorbed protein content, and increased interfacial tension, negatively affecting the emulsification properties. Compared to the HPHH treatment, HHPH treatment at homogenization pressures of 20 to 100 MPa increases EAI and ESI by 5.81–29.6 % and 5.31–25.9 %, respectively. These findings provide a fundamental basis for soybean protein manufacturers to employ appropriate processing procedures aimed at improving emulsification properties.

Green preparation of cellulose nanofibers via high-pressure homogenization and their film-forming properties

Cellulose nanofibers (CNFs) have captured extensive recognition owing to their unparalleled properties and environmental-friendliness. Green preparation process is an important step in realizing the sustainable development of CNFs. Herein, CNFs were prepared via high-pressure homogenization using commercial microcrystalline cellulose (MCC) as raw material, and subsequently employed for CNF films production by vacuum filtration. A comprehensive investigation was conducted to explore the influence of the homogenization processes on the stability, rheological characteristics of CNF suspensions, and the resultant properties of CNF films. The results showed that with the increase of homogenization pressure and cycles, the aspect ratio of CNFs increased, the dispersion stability of CNF suspensions improved, and the mechanical properties, hydrophilicity, air barrier property, and light transmittance of CNF films ascended, correspondingly. Under the homogenization pressure of 1000 bar with 15 cycles, the CNF sample exhibited an aspect ratio of 87.8 and a zeta potential of − 23.9 mV. Moreover, the CNF displayed favorable film-forming characteristics, with a tensile strength of 67 MPa, an air permeability of 4.8 µm/Pa·s, and a light transmittance of 70.2%. This work generally provides an effective and eco-friendly process for the preparation of CNFs and CNF films with high performance, which might hold great promise in biodegradable packaging application.

Ejected microcrystals probe jammed states of droplets in cyclodextrin-based emulsions

The cyclodextrin (CD)-based emulsions exhibit complex instability behaviors such as rapid flocculation and creaming, and how to capture droplet dispersion states of the emulsions remains a great challenge. Here we prepare the CD-based emulsions with different oil-water volume ratios and CD concentrations by using high-pressure homogenization, and characterize the emulsion droplets by using optical microscopy and confocal laser scanning microscopy. We evaluate the effects of homogenization pressure on the stability of the emulsions, identify armored droplets with different surface features, measure interfacial concentrations of adsorbed ICs microcrystals, and observe ejection of the oil/CD inclusion complexes (ICs) microcrystals from the droplet surface. The droplet dispersion states are sensitive to the dynamic buildup and evolving morphologies of the interfacial microcrystals, and there are clear correlations between the properties of the ejected microcrystals and the characteristics of the emulsions. We ascribe the subsequent ejection of ICs microcrystals from the droplet surface to consolidation and deformation of the films formed between neighboring droplets. The ejection of the ICs microcrystals affords a simple method to detect the droplet-droplet interactions and phase transitions in the CD-based emulsions, which might be a generic feature in the broader context of the creaming processes of emulsions.

Enhancing starch nanocrystal production and evaluating their efficacy as fat replacers in ice cream: Investigating the influence of high pressure and ultrasonication

A preparation method involving the combination of high-pressure homogenization and ultrasound (HPH-US) techniques was employed to produce starch nanocrystals (NCs) from three botanical starch sources: chestnut, corn starch, and potato starch. The optimal conditions, determined using response surface methodology, consisted of a homogenization pressure of 60 MPa and ultrasound at 280 W for 30 min. The utilization of dynamic light scattering (DLS) and transmission electron microscopy (TEM) unveiled that the resulting starch particles exhibited nanometric dimensions ranging from 135.36 to 203.47 nm. The mechanical forces generated by the HPH-US treatment significantly enhanced the physicochemical properties of the starch NCs, leading to a partial disruption of the crystalline structure. Moreover, the potential application of the synthesized starch NCs as fat replacers (FRs) was investigated. As the degree of substitution increased, notable improvements were observed in the hardness and viscosity of ice cream, accompanied by a reduction in the melting rate. The overall sensory evaluation indicated that corn starch NCs held substantial promise as a viable alternative FR for enhancing the quality of ice cream.

Solubility models of CH4, CO2, and noble gases and their geological applications

Solubility models for CH4, CO2, and noble gases are widely used in Earth Sciences, playing pivotal roles in the study of homogenization pressure of inclusions, paleoclimate variation, gas migration and accumulation, formation of helium-rich gas plays, and the volumetric ratio of gas to water in reservoirs. This paper reviews solubility models of CH4, CO2, and noble gases in pure water and aqueous NaCl solutions. Specifically, the models with high accuracy and wide applicability are introduced in detail: (1) CH4 solubility model in aqueous solutions within the range of 0–250 °C, 0.1–200 MPa, and 0–6.0 mol/kg NaCl; (2) CO2 solubility model in aqueous solutions within the range of 0–450 °C, 0.1–150 MPa, and 0–4.5 mol/kg NaCl; (3) Models for calculating the solubility and Henry's constant of atmospheric noble gases within 0–80 °C range; (4) Models for calculating the Henry's constant of noble gases in pure water; (5) Solubility models of noble gases in aqueous solutions within the range of 0–65 °C, 0.1 MPa, and 0–5.8 mol/kg NaCl. The paper also presents some calculated results obtained using these models. The solubility models of CH4 and CO2 are complex yet highly accurate, with a broad range of applications. In contrast, the solubility models of noble gases exhibit relatively lower accuracy and a narrower application range, necessitating corrections. In the noble gases-CO2-H2O system, low-density CO2 has little effect on the solubility of noble gases, whereas high-density CO2 significantly influences their solubilities. Currently, accurately evaluating the solubility of CH4, CO2, and noble gases in their mixtures proves challenging, warranting further research into solubility models for gas mixtures.

Fabrication of nanoemulsion stabilized by high-pressure modified soy protein isolate-genistein for the encapsulation of lutein

In this study, we evaluated the interaction between high-pressure homogenization modified soybean isolate protein (HSPI) and genistein (GE), and constructed nanoemulsions for the co-encapsulated of GE and lutein using HSPI-GE as emulsifier. SPI formed complexes with GE mainly through hydrophobic interactions, and high-pressure homogenization treatment improved the interaction between SPI and GE. When the homogenization pressure was 120 MPa, the emulsification activity and emulsion stability indexes of HSPI-GE reached 196.71 m2g-1 and 237.98min, and the zeta potential of HSPI-GE nanoemulsion was −34.15 mV. Additionally, the encapsulation efficiency of HSPI-GE nanoemulsion was up to 93.88% and its storage stability was up to 66.01% after 20 d of storage. The HSPI-GE nanoemulsions achieved slow release of co-encapsulated GE and lutein and improved their bioaccessibility to 74.47% and 80.46% in in vitro simulated digestion. This work provides a theoretical basis for further studies on the application of HSPI-GE in lutein delivery systems.

The effect of homogenisation pressure on the microstructure of milk during evaporation and drying: particle-size distribution, electronic scanning microscopy, water activity and isotherm.

Homogenisation is a widely used technique in manufacturing powdered milk with a direct impact on product solubility, and the homogenisation pressure is a central attribute of this process. We aimed to understand the effect of increasing homogenisation pressures (0/0, 15/5, and 75/5 MPa, 1st/2nd stages) on particle-size distribution during homogenised whole milk powder manufacture and rehydration of the final product. The fluid milk was thermally treated, homogenised, concentrated by rotary evaporation, and then dried using a spray dryer. Particle size (Dv90) was monitored at all stages of the manufacturing process. The final product (milk powder) was analysed using particle-size distribution, electronic scanning microscopy, water activity, and isotherms. The results demonstrated that increasing the homogenisation pressure leads to milk powder with smaller particle size when rehydrated (Dv90 values: 6.08, 1.48 and 0.64 μm for 0, 20 and 80 MPa, respectively). Furthermore, the volume (%) of the particles in the 'sub-micro' region (smaller than 1.0 μm) presented an inversely proportional profile to the homogenisation pressure (homogenised fluid milk: 86.1, 29.3 and 2.4%; concentrated milk: 86.1, 26.5 and 5.7%, and reconstituted milk powder: 84.2, 31.8 and 10.9%). Surprisingly, this pattern was not observed in the SPAN value (which corresponds to the width or range of the size distribution based on the volume). Additionally, the increase in the homogenisation pressure did not affect the sorption isotherm pattern. These results demonstrate that increasing the homogenisation pressure decreases the particle size of the reconstituted powdered milk, indicating the potential for future studies on how this phenomenon affects its physicochemical and final product properties.

The effect of high-temperature heat treatment and homogenization on the microstructure of set yogurt curd networks.

Set yogurt's physical characteristics are greatly affected by the homogenization and heat treatment processes. In our previous study, set yogurt treated at 130°C and with the fat particle size reduced to ≤0.6 μm had equivalent curd strength, less syneresis and smoother texture than yogurt treated at 95°C. When investigating the mechanisms underlying yogurt's physical properties, it is important to evaluate the yogurt's microstructure. We conducted electron microscopy evaluations to investigate the mechanisms of changes in yogurt's physical properties caused by 130°C heat treatment and by a reduction in the fat globule size. We prepared yogurt mixtures by combining heat treatment at 95 and 130°C and homogenization pressure at 10 + 5 and 35 + 5 MPa and then fermented the mixtures in a common yogurt starter. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for the structural observations. Fine particles were observed on the surface of the casein micelles of the yogurt treated at 95°C, and the coalescence density between micelles was high. The surface of the yogurt treated at 130°C had few fine particles, and the coalescence density between micelles was low. The yogurt treated at 130°C with 35 + 5 MPa homogenization had low coalescence density between casein micelles, but smaller-particle-size fat globules increased the network density. Approximately 30% of the fat globules were estimated to be incorporated into the yogurt networks compared to the volume of casein micelles. We speculate that 130°C heat treatment alters the structure of whey protein on the surface of casein micelles and interferes with network formation, but reducing the size of fat globules reinforces the network as a pseudoprotein.

Encapsulation efficiency and fatty acid analysis of chia seed oil microencapsulated by freeze-drying using combinations of wall material

Chia seed oil (CSO) was encapsulated using whey protein concentrate (WPC) and modified tapioca starch (MTS) through freeze-drying. A central composite design was used to evaluate the effect of independent variables (MTS:WPC ratio, homogenization pressure, and oil content). Encapsulation efficiency (EE) and α-linolenic acid content (ALA) were evaluated for all runs. The results showed that higher MTS ratios led to maximum ALA retention, while higher WPC ratios led to maximum EE. The optimized conditions resulted in high EE (97 %), ALA content (59.54 %), and a Ω-3:Ω-6 ratio (3.34). The fatty acid composition, oxidative and thermal stability showed that the MTS:WPC ratio of 25:75 was the best combination for encapsulating CSO. The encapsulated CSO with a balanced Ω-3:Ω-6 ratio can be used as a functional ingredient in foods for health benefits.

A Method to Correct Steady-State Relative Permeability Measurements for Inhomogeneous Saturation Profiles in One-Dimensional Flow

AbstractTraditionally, steady-state relative permeability is calculated from measurements on small rock samples using Darcy’s law and assuming a homogenous saturation profile and constant capillary pressure. However, these assumptions are rarely correct as local inhomogeneities exist; furthermore, the wetting phase tends to be retained at the outlet–the so-called capillary end effect. We have introduced a new method that corrects the relative permeabilities, analytically, for an inhomogeneous saturation profile along the flow direction. The only data required are the measured pressure drops for different fractional flow values, an estimate of capillary pressure, and the saturation profiles. An optimization routine is applied to find the range of relative permeability values consistent with the uncertainty in the measured pressure. Assuming a homogenous saturation profile systematically underestimates the relative permeability and this effect is most marked for media where one of the phases is strongly wetting with a noticeable capillary end effect. Relative permeabilities from seven two-phase flow experiments in centimetre-scale samples with different wettability were corrected while reconciling some hitherto apparently contradictory results. We reproduce relative permeabilities of water-wet Bentheimer sandstone that are closer to other measurements in the literature on larger samples than the original analysis. Furthermore, we find that the water relative permeability during waterflooding a carbonate sample with a wide range of pore sizes can be high, due to good connectivity through the microporosity. For mixed-wet media with lower capillary pressure and less variable saturation profiles, the corrections are less significant.

New methods to reconstruct paleo-oil and gas compositions and P-T trapping conditions of hydrocarbon fluid inclusions in sedimentary basins

Accurate predictions of fluid composition and P-T trapping condition of hydrocarbon fluid inclusions (HFIs) is crucial to understand complex oil and gas charging history and accumulation mechanism. However, traditional P-T prediction methods are not enough powerful to get reliable results because of difficulty in direct composition measurement and great uncertainties in indirect composition prediction for single HFI. In this study, we collected 296 crude oil and 983 gas condensate fluids to develop new composition and trapping pressure (Pt) prediction models. Based on the measured fluid composition, saturation pressure (corresponding to homogenization pressure, Ph) and volume data, we firstly calibrate the Ph, the degree of bubble filling (Fv, at 20 °C) and isochores predictions for the measured fluids through matching saturation pressure and volume calibration and then established a standard fluid database with fluid composition, Ph, Fv and Pt. For the first time, a new hydrocarbon fluid composition prediction model was developed which is only function of Fv and homogenization temperature (Th) of HFIs. The new composition model allows directly predicting the entire fluid compositions from methane (C1) to heptane plus (C7+) fractions in HFI based on Fv and Th. Furthermore, we developed different Pt prediction models for varying fluid compositions and phase states of HFIs. For oil-bearing fluid inclusions which homogenize into liquid phase (OFIL) methane molar content is the only variable that is needed to predict Pt with a high degree of accuracy (8.2–12.3% for average absolute deviation, AAD). However, for gas condensate-bearing fluid inclusions (GCFI), more composition (C1–C7+) together with the physical property (molecular weight and specific gravity) of C7+ composition must be incorporated into the prediction model to obtain a better prediction accuracy of Pt. The new Pt prediction models give prediction accuracy of 11.2–17.6% (AAD) for GCFIL (homogenizing into liquid phase), and 15.9–22.8% (AAD) for GCFIG (homogenizing into gas phase). Our new composition and Pt prediction models can give the best and fastest predictions of hydrocarbon fluid composition and trapping condition and are of great significance for petroleum charging history reconstruction in sedimentary basins.

A homogeneous atmospheric pressure air plasma in a 10 mm gap based on a three-electrode configuration

Generation of atmospheric pressure homogeneous air plasma in a large gap (> 4 mm) is a challenge. In this study, an atmospheric pressure homogeneous air plasma generated in a gap up to 10 mm is reported, which is based on a three-electrode configuration, where a high-voltage (HV) electrode and a middle electrode form a surface dielectric barrier discharge (S-DBD), and together with the ground electrode form the main volume discharge. High-speed photographs confirm that the discharge in the main gap is homogeneous. The gas temperature of the plasma estimated from the N2(C3∏u-B3∏g) (Δv = −2) emission is about 320 K, which is close to room temperature. A detailed analysis shows that the discharge ignited between the HV electrode and the middle electrode is serving as an electron source, and the electrons deposited on the dielectric plate are due to the S-DBD along with the applied voltage generating a driving force, which results in a high concentration of seed electrons in the main gap and induces the homogeneous plasma. Further analysis shows that the electric field in the main gap is only about 18.45 kV·cm−1, which is much lower than the typical breakdown electric field of 30 kV·cm−1 for atmospheric pressure air discharge.

Effects of high-pressure homogenization on the physicochemical, foaming, and emulsifying properties of chickpea protein

In order to expand the utilization of chickpeas in various food products, this study investigated the effects of different homogenization pressures (0–150 MPa) and cycles (1–3) on the physicochemical, and functional properties of chickpea protein. After high-pressure homogenization (HPH) treatment, hydrophobic groups and sulfhydryl groups of chickpea protein was exposed which increased its surface hydrophobicity and decreased its total sulfhydryl content. SDS-PAGE analysis showed that the molecular weight of modified chickpea protein remained unchanged. The particle size and turbidity of chickpea protein significantly decreased with an increase in homogenization pressure and cycles. Furthermore, the solubility, foaming, and emulsifying properties of chickpea protein were all enhanced by HPH treatment. In addition, the emulsions prepared by modified chickpea protein showed better stability capacity due to its smaller particle size and higher zeta potential. Therefore, HPH might be an effective technique to improve the functional properties of chickpea protein.

Impact of non-thermal modifications on the physicochemical properties and functionality of litchi pomace dietary fibre

Pomace is frequently underestimated as a complex by-product. High pressure homogenisation (HPH), enzymatic hydrolysis (EH) and high hydrostatic pressure (HHP) modifications are applied to improve the functional properties of litchi pomace insoluble dietary fibre (LPDF). The relationships between physicochemical properties and structural alterations and digestibility of LPDF are studied. The results showed that HPH, EH and HHP changed the LPDF's microstructure, causing it to develop more porous structures. Meanwhile, HPH modification exhibited a remarkable effect on LPDF's water holding (15.6 g/g), water swelling (26.1 mL/g) and oil retention (5.4 g/g) capabilities, resulting in the change of the complexity of the neutral sugar side chain. Notably, the highest total phenol content (3.4 GAE mg/g) and antioxidant activities (DPPH 153.6, ABTS 188.9, FRAP 195.1 μmol Trolox/g) were also observed in LPDF modified with HPH. Moreover, the diversity of structural features and high affinity of modified LPDFs are conducive to its functional properties, i.e., inhibition of starch digestion. The remarkable potential of LPDF modified with HPH was attributed to the beneficial effects of dietary fibre on human health. As a result, litchi pomace could be a useful and effective source of functional fibres. The incorporation of litchi pomace into the human diet is still underexplored but is a promising alternative.

Production of microencapsulated enzyme-modified cheese (EMC) powder: Impact of wall material combinations, their concentrations, and homogenisation pressures

Enzyme-modified cheese (EMC) is a concentrated cheese flavour, and microencapsulation can improve its physical properties while preserving flavour. This study performed microencapsulation of EMC in two stages: emulsification and spray drying. Different combinations of proteins (sodium caseinate, whey protein concentrate) and carbohydrates (lactose, maltodextrin, oxidised starch) at varying homogenisation pressures (500, 1000, 2000 bar) were used to determine the most appropriate wall material combination, and emulsions with different concentrations of wall materials (23, 36.5, 50%) spray-dried to select the best microencapsulation formulation. Emulsion properties and the physical, chemical, and sensorial characteristics of the powders were evaluated. Microencapsulation enhanced the physical properties of powders, increased the drying yield, reduced the loss of free fatty acids, and increased the concentration of ester compounds. The best powder was produced using whey protein concentrate/lactose at a concentration of 50% of the total dry matter in the emulsion, with a homogenisation pressure of 500 bar.