High-pressure Homogenization Process Research Articles

Effect of different yeast-derived products on a red wine polyphenolic composition: influence of the wine age

The name “yeast-derived products” (YDPs) refers to different preparations obtained from yeast cells through various processes. These YDPs have different characteristics and applications in oenology, one being the improvement of the sensory properties of wines. This work aimed to identify the impact of YDPs obtained from different yeast strains and through different downstream inactivation processes on polyphenols in a red wine at different aging times. At an oenological dosage of 40 mg/L in a young wine, the addition of YDPs resulted in a variable decrease in total polyphenol index (TPI) (2 to 9 % depending on the YDPs) and a significant decrease in the precipitation of tannins (15 to 50 %) and high molecular weight (HMW) pigments (19 to 85 %) were obtained in the BSA assay, thus demonstrating the involvement of tannins and HMW pigments in interactions with the studied yeast-derived products. Pigment involvement led to a change in colour indices (L*a*b* and colour intensity), but in most cases this change was not visible to the human eye at the oenological dosage tested (40 mg/L). Experiments conducted on both the young wine and the same wine aged for three months using the same yeast-derived products, dosages and aging conditions revealed the influence of the chemical evolution of polyphenols on their interactions with YDPs. The significant variation observed in this study highlights the critical role of yeast selection and the yeast fragmentation downstream process on YDP efficiency. The high-pressure homogenisation (HPH) yeast fractions were shown to be more efficient than the corresponding whole yeast cells. Increasing the contact surface area between yeast cell constituents and wine matrix enabled by the HPH process may be a key strategy for enhancing the effectiveness of yeast derivatives in red wines, and in aged wines in particular, in which the phenolic compounds underwent changes and exhibited less interaction with the studied yeast-derived products. This research has contributed to increasing our understanding of and the potential for apply these processing aids in oenology.

Molecular motion behaviors of starch affect starch-polyphenol inclusion complex and digestibility among different stilbenes polyphenol structures

Starch-polyphenol V-type inclusion complex has become a hot topic due to its anti-digestibility and nutritional function. This paper aimed to explore the molecular motion behavior of starch affects starch-polyphenol inclusion complex and digestibility among different stilbene polyphenol structures (resveratrol (RA), pterostilbene (PB) and polydatin (PD) via the high-pressure homogenization (HPH) and heat moisture treatment (HMT) processes), which represented the fully extended and limited molecular motion behavior of starch, respectively. These results revealed distinct trends in complex formation among different stilbenes polyphenol structures, highlighting RA as particularly conducive to increasing single helix and V-type crystalline structures with the highest resistant starch (RS) content of 28.11 % due to its smaller steric hindrance. Novelty, in HPH environments with extended molecular motion behavior, the steric hindrance and hydrophobicity/CH-π interactions of polyphenols influence complex formation in the order of RA > PB > PD. Conversely, in HMT systems with limited molecular motion behavior, the limited movement of molecules emphasized the importance of hydrogen bond interactions between polyphenols and starch. Thus, the glucoside in PD enhanced its interaction with starch compared to methoxy-modified PB, leading to increased formation of inclusion complex with RS content of 18.61 %. Overall, these findings deepen the understanding of starch-polyphenol interactions.

Set yogurt incorporated with insoluble dietary fiber maintains non-sedimentation: Combined alkaline hydrogen peroxide modification and high-pressure homogenization process

Insoluble dietary fiber (IDF) settles in set yogurt due to its water insolubility. Making IDF non-settling in set yogurt without thickeners is the current objective. This study attempted to modify IDF with alkaline hydrogen peroxide (AHP) and combine it with a high-pressure homogenization (HPH) process to resolve the settling of IDF in set yogurt. The results showed that AHP-treated IDF (IDF-AHP) altered the structure of IDF, enhanced hydration properties, and had no hydrogen peroxide residue. Set yogurt incorporated with 1, 3, and 5% (w/w) IDF-AHP underwent a HPH process, resulting in non-settling IDF-AHP. The water retention, firmness, and cohesion of yogurt were improved, and the storage modulus (G′) increased during 28-day refrigeration. and the casein gel properties were improved. These results show that combining AHP with HPH treatment prevented the settling of IDF in yogurt and improved its texture. Further studies revealed that AHP and HPH were necessary to prevent IDF from settling in yogurt. This study confirms the applicability of the method and provides new ideas for the commercial production of IDF yogurt.

Effect of sesame protein isolate modified by high-pressure homogenization, high-intensity ultrasound, and high-pressure processing on the colloidal stability of sesame paste: Determination of physicochemical, rheological, microstructural properties and storage stability

In this study, sesame protein isolate modified with different emerging technologies, including high-pressure homogenization, high-intensity ultrasonication, and high-hydrostatic pressure, was applied to improve the stability of sesame paste. Sesame protein addition reduced the phase separation by up to 48% in sesame paste compared to the sample (control) without protein addition, and also significantly enhanced the firmness and spreadability. With the addition of sesame protein isolate, the sesame paste samples formed a denser and more compact appearance. The flow characteristics of samples were better fitted by the Herschel-Bulkley equation, and modifying the added protein also played an essential role in improving the flow properties of sesame paste samples. Phase separation and oxidative stability of sesame paste were significantly improved by the addition of modified protein. Overall, the results indicated that sesame protein modified with HPH technology has a significant potential to improve the quality of sesame paste and prevent phase separation.

Effect of Combined High-Pressure Homogenization and Biotechnological Processes on Chitin, Protein, and Antioxidant Activity of Cricket Powder-Based Ingredients

The main objective of this work was to evaluate the combined effect of a biotechnology process, based on selected yeast strains, and a high-pressure homogenization (HPH) treatment on the microbiological quality, structural organization of proteins, chitin content, and antioxidant activity of a mixture of cricket powder (Acheta domesticus) and water. Compared to untreated samples, the cricket matrix treated with HPH four times at 180 MPa promoted the growth of the inoculated Yarrowia lipolytica and Debaryomyces hansenii strains. HPH did not affect the concentration of chitin; however, the combination with microorganisms tended to reduce the content. Although the antioxidant activity increased from 0.52 to 0.68 TAC mM/TE after a 48 h incubation in the control, it was further improved by the combination of HPH and D. hansenii metabolism, reaching a value of 0.77 TAC mM/TE. The combination of the two approaches also promoted a reduction in the intensity of bands with molecular weights between 31 and 21.5 kDa in favor of bands with a lower molecular weight. In addition, HPH treatment reduced the number of accessible thiols, suggesting protein structure changes that may further impact the technological properties of cricket powder.

Complexation temperature regulated the structure and digestibility of pea starch–gallic acid complexes during high pressure homogenization

Formation of starch–polyphenol complexes by high pressure homogenization (HPH) is widely used to reduce starch digestibility and delay the postprandial glycemic response, thereby benefiting obesity and associated metabolic diseases. This study investigated the effect of complexation temperature on multi–scale structures, physicochemical and digestive properties of pea starch–gallic acid (PS–GA) complexes during HPH process, while also elucidating the corresponding molecular mechanism regulating in vitro digestibility. The results demonstrated that elevating complexation temperature from 30 °C to 100 °C promoted the interaction between PS and GA and reached a peak complex index of 9.22 % at 90 °C through non–covalent binding. The enhanced interaction led to the formation of ordered multi–scale structures within PS–GA complexes, characterized by larger particles that exhibited greater thermal stability and elastic properties. Consequently, the PS–GA complexes exhibited substantially reduced digestion rates with the content of resistant starch increased from 28.50 % to 38.26 %. The potential molecular mechanism underlying how complexation temperature regulated digestibility of PS–GA complexes might be attributed to the synergistic effect of the physical barriers from newly ordered structure and inhibitory effect of GA against digestive enzymes. Overall, our findings contribute to the advancement of current knowledge regarding starch–polyphenol interactions and promote the development of functional starches with low postprandial glycemic responses.

Microwave-assisted DES fabrication of lignin-containing cellulose nanofibrils and its derived composite conductive hydrogel

Deep eutectic solvents (DES) have been regarded as green solvents in the biorefinery of lignocellulosic biomass, but long duration time has severely limited efficiency. The microwave-assisted DES pretreatment along with enzymatic hydrolysis and high-pressure homogenization process was proposed to produce lignin-containing cellulose nanofibrils (LCNF) from corncob. Benefiting from microwave-assisted DES pretreatment, the duration time was greatly shortened; meanwhile the effects of different kinds of DES on the resultant LCNF were investigated. The results showed that, the microwave-assisted DES fabricated LCNF (M-LCNF) was successfully obtained, exhibiting good nano size, thermal stability, colloidal stability, and fluorescence. M-LCNF was further introduced into phytic acid (PA) enhanced poly(acrylamide-co-acrylic acid) (P(AM-co-AA)) network and constructed composite conductive hydrogels (PLP). The obtained hydrogels exhibited good mechanical strength, UV blocking ability, fluorescence, and conductivity. A simple battery assembled with the resultant PLP as electrolyte had an out voltage of 2.41 V. The composite conductive hydrogel showed good sensing performance towards different stimuli (e.g., stretching and compression) and human motions in real time. It is expected that this research would provide an alternative way for green fabrication of LCNF and potential application of LCNF in flexible sensors.

The Effect of High-Pressure Homogenization Conditions on the Physicochemical Properties and Stability of Designed Fluconazole-Loaded Ocular Nanoemulsions.

The growing interest in high-energy emulsification is a result of its scalability, which is important from an industrial perspective and allows for a more reproducible and efficient production of pharmaceutical formulations. The aim of this study was to evaluate the effect of composition, mainly a fixed surfactant/cosurfactant (Smix) ratio, their concentration, and the parameters of high-pressure homogenization (HPH) processing on the quality and stability of ophthalmic fluconazole-loaded nanoemulsions. After a physicochemical analysis of nanoemulsions containing 20% w/w of oil, as optimal conditions for the HPH process, three cycles at a pressure of 1000 bar were established, obtaining formulations with an average droplet diameter size in the range of 80.63-129.68 nm and PDI values below 0.25. While it was expected that an increasing cosurfactant concentration decreased the droplet size, in the case of formulations containing Tween 20 and 10% w/w of cosurfactants, "over-processing" was observed, identified by the droplet size and polydispersity index increase. Consecutively, the selected formulations were evaluated for in vitro drug release in Franz's cell, antifungal activity, and 30-day stability using NMR spectroscopy. An antifungal activity test showed no significant difference in the antifungal activity between optimal fluconazole-loaded nanoemulsions and a 0.3% aqueous drug solution, but previously, research showed that prepared formulations were characterized by a higher viscosity and satisfactory prolonged release compared to a control. In a 30-day stability study, it was observed that higher HLB values of the used surfactants decreased the stability of the formulations in the following order: Kolliphor EL, Tween 80, Tween 20. The NMR spectra confirmed that Kolliphor EL-based formulations ensured the higher stability of the nanoemulsion composition in comparison to Tween 80 and a better stabilizing effect of propylene glycol as a cosurfactant in comparison to PEG 200. Therefore, the optimization of HPH technology should be focused on the selection of Smix and the Smix:oil ratio in order to prepare stable formulations of high quality.

Enhancing pea protein isolate functionality: A comparative study of high-pressure homogenization, ultrasonic treatment, and combined processing techniques

Pea protein has attracted widespread attention due to its high nutritional value, low allergenicity, non-GMO status, and broad availability. However, compared to animal proteins, pea protein has inferior functional properties, which limits its application in the food industry. This study used pea protein isolate (PPI) as the main raw material and investigated the effects of high-pressure homogenization (HPH), ultrasonic treatment (US), and the combination of the two in different orders on the structure and function of PPI. The results showed that HPH or US promoted the transformation of PPI insoluble suspension into a uniform protein dispersion, significantly reducing particle size, unfolding the spatial structure, exposing more amino acid residues. These structural changes resulted in a substantial increase in the solubility, foaming capacity and emulsifying activity of PPI. Moreover, the combined treatments further impacted the properties of PPI, largely depending on the order of the processing steps; the combination of HPH-US exhibited the best functional characteristics.

Nanostructured Cellulose-Based Aerogels: Influence of Chemical/Mechanical Cascade Processes on Quality Index for Benchmarking Dye Pollutant Adsorbents in Wastewater Treatment.

(1) Background: Nanostructured cellulose has emerged as an efficient bio-adsorbent aerogel material, offering biocompatibility and renewable sourcing advantages. This study focuses on isolating (ligno)cellulose nanofibers ((L)CNFs) from barley straw and producing aerogels to develop sustainable and highly efficient decontamination systems. (2) Methods: (Ligno)cellulose pulp has been isolated from barley straw through a pulping process, and was subsequently deconstructed into nanofibers employing various pre-treatment methods (TEMPO-mediated oxidation process or PFI beater mechanical treatment) followed by the high-pressure homogenization (HPH) process. (3) Results: The aerogels made by (L)CNFs, with a higher crystallinity degree, larger aspect ratio, lower shrinkage rate, and higher Young's modulus than cellulose aerogels, successfully adsorb and remove organic dye pollutants from wastewater. (L)CNF-based aerogels, with a quality index (determined using four characterization parameters) above 70%, exhibited outstanding contaminant removal capacity over 80%. The high specific surface area of nanocellulose isolated using the TEMPO oxidation process significantly enhanced the affinity and interactions between hydroxyl and carboxyl groups of nanofibers and cationic groups of contaminants. The efficacy in adsorbing cationic dyes in wastewater onto the aerogels was verified by the Langmuir adsorption isotherm model. (4) Conclusions: This study offers insights into designing and applying advanced (L)CNF-based aerogels as efficient wastewater decontamination and environmental remediation platforms.

The effects of ultrasound and high pressure homogenization processes on physiochemical properties of hemp seed milk

One of the problems with plant-based milk drinks produced from seeds that are high in protein, such as hemp milk, is coagulating of the proteins with heat treatment. In this case, the effect of the interaction of the methods used in the production of hemp milk is unknown. This study aimed to evaluate the effect of ultrasound (US), high-pressure homogenization (HPH), and a combination of both on the physiochemical properties of hempseed milk production. The optimum conditions for the ultrasound and combined processes were determined using response surface methodology (RSM). In the HPH process (0–200 mPa), the control sample was statistically different (p<0.05) from the applied samples for the responses as L*, a*, b*, TPC, serum separation, and Dx(90). A prediction equation expressing L* response in terms of power and time was found for US-applied 13 trial runs. For HPH+US combined process with 20 trials, a* and Dx(90) responses were found statistically important (p<0.05) for prediction models. For prediction of the US process was determined as 45.86 amplitude with 4.96 min.

Dexamethasone acetate nanocrystals: characterization and dissolution studies in presence of polymorphic phases.

A drug with poor water-solubility, like Dexamethasone acetate, can present lower bioavailability conventional for pharmaceutical formulations, and the presence of polymorphs in the raw material can lead to drug quality problems. In this study, nanocrystals of dexamethasone acetate were synthesized by high pressure homogenizer (HPH) method in surfactant poloxamer 188 (P188) solid dispersion and the bioavailable in raw material with polymorphism presence was evaluated. The powder pre-suspension was prepared by the HPH process, and the nanoparticles formed were incorporated in P188 solutions. The nanocrystals formed were characterized by techniques of XRD, SEM, FTIR, thermal analysis by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), dynamic light scattering (DLS) to analyze the particle size and zeta potential, and in vitro evaluation by dissolution studies. The characterization techniques were adequate to show the presence of raw material with physical moisture between two dexamethasone acetate polymorphs. The nanocrystals formed in the presence of the P188 in the formulation showed a considerable increase in the rate of dissolution of the drug in the medium and in the size of the stable nanocrystals, even in the presence of dexamethasone acetate polymorphs. The results showed that it was possible to produce dexamethasone nanocrystals by HPH process with regular size by the presence of the small amount of P188 surfactant. This article presents a novelty in the development of dexamethasone nanoparticles that have different polymorphic forms in their physical composition.

Improvement in the Stability and Bioaccessibility of Carotenoid and Carotenoid Esters from a Papaya By-Product Using O/W Emulsions.

The aim of the present work was to improve the stability and bioaccessibility of carotenoids from green oil extracts obtained from papaya by-products using oil-in-water (O/W) emulsions. The effects of different concentrations of pectin (1%, 2%, and 3%), a high-molecular-size emulsifier, together with Tween 20, a low-molecular-size emulsifier, high-speed homogenization conditions (time: 2, 3, 4, and 5 min; rpm: 9500, 12,000, 14,000, and 16,000 rpm), and high-pressure homogenization (HPH) (100 MPa for five cycles) were evaluated to determine the optimal conditions for obtaining O/W stable emulsions with encapsulated carotenoids. Soybean, sunflower, and coconut oils were used to formulate these O/W emulsions. The bioaccessibility of the main individual encapsulated papaya carotenoids was evaluated using the INFOGEST digestion methodology. In addition, the microstructures (confocal and optical microscopy) of the O/W carotenoid emulsions and their behavior during in vitro digestion phases were studied. Sunflower O/W carotenoid emulsions showed smaller mean particle size, higher negative ζ-potential, and higher viscosity than soybean O/W emulsions. Particle size reduction in the O/W emulsions using the HPH process improved the bioaccessibility of papaya encapsulated carotenoids. In these O/W emulsions, depending on the vegetable oil, lycopene was the carotenoid with the highest bioaccessibility (71-64%), followed by (all-E)-β-carotene (18%), (all-E)-β-cryptoxanthin (15%), and (all-E)-β-cryptoxanthin laurate (7-4%). These results highlight the potential of using green carotenoid papaya extracts to formulate O/W emulsions to enhance carotenoid bioactivity by efficiently preventing degradation and increasing in vitro bioaccessibility.

Brazil Nut (Bertholletia excelsa) Beverage Processed by High-Pressure Homogenization: Changes in Main Components and Antioxidant Capacity during Cold Storage.

High-pressure homogenization (HPH) is an emerging technology for obtaining physical and microbial stability of plant-based milks, but there is little information on the effects of this technology on the phytochemical components of the processed plant food beverage and during its cold storage. The effect of three selected HPH treatments (180 MPa/25 °C, 150 MPa/55 °C, and 50 MPa/75 °C) and pasteurization (PAS) (63 °C, 20 min) on minor lipid constituents, total proteins, phenolic compounds, antioxidant capacity, and essential minerals of Brazil nut beverage (BNB) were studied. Additionally, the study of the possible changes in these constituents was carried out during cold storage at 5 °C for 21 days. The fatty acid profile (dominated by oleic acid and linoleic acid), free fatty acid content, protein, and essential minerals (notable source of Se and Cu) of the processed BNB remained almost stable to treatments (HPH and PAS). Specifically, reductions in squalene (22.7 to 26.4%) and γ-γ-tocopherol (28.4 to 36%) were observed in beverages processed via both non-thermal HPH and thermal PAS, but β-sitosterol remained unchanged. Total phenolics were reduced (24 to 30%) after both treatments, a factor that influenced the observed antioxidant capacity. The studied individual phenolics in BNB were gallic acid, catechin, epicatechin, catechin gallate, and ellagic acid, being the most abundant compounds. During cold storage (5 °C) up to 21 days, changes in the content of phytochemicals, minerals, and total proteins were not noticeable for any treated beverages, and no lipolysis processes were promoted. Therefore, after the application of HPH processing, Brazil nut beverage (BNB) maintained almost unaltered levels of bioactive compounds, essential minerals, total protein, and oxidative stability, remarkable characteristics for its potential development as a functional food.

Food Emulsion Gels from Plant-Based Ingredients: Formulation, Processing, and Potential Applications.

Recent advances in the understanding of formulations and processing techniques have allowed for greater freedom in plant-based emulsion gel design to better recreate conventional animal-based foods. The roles of plant-based proteins, polysaccharides, and lipids in the formulation of emulsion gels and relevant processing techniques such as high-pressure homogenization (HPH), ultrasound (UH), and microfluidization (MF), were discussed in correlation with the effects of varying HPH, UH, and MF processing parameters on emulsion gel properties. The characterization methods for plant-based emulsion gels to quantify their rheological, thermal, and textural properties, as well as gel microstructure, were presented with a focus on how they can be applied for food purposes. Finally, the potential applications of plant-based emulsion gels, such as dairy and meat alternatives, condiments, baked goods, and functional foods, were discussed with a focus on sensory properties and consumer acceptance. This study found that the implementation of plant-based emulsion gel in food is promising to date despite persisting challenges. This review will provide valuable insights for researchers and industry professionals looking to understand and utilize plant-based food emulsion gels.

The Impact of High-Pressure Homogenization and Thermal Processing on the Functional Properties of De-Fatted Chickpea Flour Dispersion

Defatted chickpea flour (DCF), a rich source of protein and starch, is frequently utilized in the food industry. Two crucial methods of modifying food materials are high-pressure homogenization (HPH) and heat treatment (HT). This study investigates the effect of co-treatment (HPH-HT) on the particle size, rheological behavior, and thermal characteristics of DCF suspensions. The results indicate that both HPH and HT can result in a more uniform distribution of particle size in the suspensions. The effect of HPH on G' was observed to be reductionary, whereas HT increased it. Nevertheless, the HPH-HT treatment further amplified G' (notably in high-concentration DCF), which demonstrates that the solid properties of DCF are improved. The apparent viscosity of the suspensions increased with individual and combined treatments, with the HPH-HT treatment of DCF12% exhibiting the most significant increase (from 0.005 to 9.5 Pa·s). The rheological behavior of DCF8% with HPH-HT treatment was found to be comparable to that of DCF12% treated only with HT. In conclusion, HPH-HT treatment shows a synergistic impact of HPH and HT on the rheological properties of DCF suspensions, however, it has limited effect on the particle size distribution and freeze-thaw stability.

Validation of High-Pressure Homogenization Process to Pasteurize Brazil Nut (Bertholletia excelsa) Beverages: Sensorial and Quality Characteristics during Cold Storage

The effect of high-pressure homogenization (HPH) on the inactivation of Escherichia coli and the stability of the quality properties of Brazil nut beverages were studied. E. coli was used as target microorganism to validate the HPH process (pressures from 50 to 180 MPa and inlet temperatures (Ti) from 25 to 75 °C). Cold storage (5 °C) for 21 days was conducted to establish the shelf-life of BN beverages, in terms of their microbiological, physical, physicochemical, and sensorial stability. HPH-treated samples were compared to pasteurized BN beverages (63 °C for 20 min). The combination of Ti and the pressure of the HPH process (50 to 150 MPa/75 °C and 180 MPa/25 °C) had a significant effect on E. coli inactivation (8.2 log CFU/mL). During storage at 5 °C, the growth of mesophilic aerobes in processed BN beverages was controlled by the HPH process. Oxidative stability (TBAR assay) and physicochemical properties (pH, acidity, and °Brix) were evaluated during cold storage, showing good stability. Additionally, HPH-treated beverages showed a reduction in their particle size and the formation of more stable protein aggregates, which favored the beverages’ whiteness (color). The HPH process could be an alternative to pasteurization to obtain Brazil nut beverages with an acceptable microbiological shelf life (≥21 days at 5 °C) and high-quality characteristics without the use of any additives.

Influence of High-Pressure Homogenization on the Physicochemical Properties and Betalain Pigments of Red Beetroot (Beta vulgaris L.) Juice.

High-pressure homogenization (HPH) is considered an innovative and modern method of processing and preserving liquid and semi-liquid foods. The aim of this research was to examine the impact of HPH processing on the content of betalain pigments and physicochemical properties of beetroot juice. Combinations of the following HPH parameters were tested: the pressure used (50, 100, 140 MPa), the number of cycles (1 and 3) and the applied cooling or no cooling. The physicochemical analysis of the obtained beetroot juices was based on the determination of the extract, acidity, turbidity, viscosity and color values. Use of higher pressures and a greater number of cycles reduces the turbidity (NTU) of the juice. Moreover, in order to maintain the highest possible extract content and a slight color change of the beetroot juice, it was crucial to perform sample cooling after the HPH process. The quantitative and qualitative profiles of betalains have been also determined in the juices. In terms of the content of betacyanins and betaxanthins, the highest values were found in untreated juice at 75.3 mg and 24.8 mg per 100 mL, respectively. The high-pressure homogenization process resulted in a decrease in the content of betacyanins in the range of 8.5-20.2% and of betaxanthins in the range of 6.5-15.0%, depending on the parameters used. Studies have shown that that the number of cycles was irrelevant, but an increase in pressure from 50 MPa to 100 or 140 MPa had a negative effect on pigment content. Additionally, juice cooling significantly limits the degradation of betalains in beetroot juice.

Surface Properties of Graffiti Coatings on Sensitive Surfaces Concerning Their Removal with Formulations Based on the Amino-Acid-Type Surfactants.

Water-in-oil (w/o) nanoemulsions stabilized with amino acid surfactants (AAS) are one example of nanotechnology detergents of the "brush on, wipe off"-type for removing graffiti coatings from different sensitive surfaces. The high-pressure homogenization (HPH) process was used to obtain the nanostructured fluids (NSFs), including the non-toxic and eco-friendly components such as AAS, esterified vegetable oils, and ethyl lactate. The most effective NSF detergent was determined by response surface methodology (RSM) optimization. Afterwards, several surface properties, i.e., topography, wettability, surface free energy, and the work of water adhesion to surfaces before and after their coverage with the black graffiti paint, as well as after the removal of the paint layers by the eco-remover, were determined. It was found that the removal of graffiti with the use of the NSF detergent is more dependent on the energetic properties and microporous structure of the paint coatings than on the properties of the substrates on which the layers were deposited. The use of NSFs and knowledge of the surface properties could enable the development of versatile detergents that would remove unwanted contamination from various surfaces easily and in a controlled way.

Properties of bacterial cellulose acetate nanocomposite with TiO2 nanoparticle and graphene reinforcement

Agricultural waste is considered a promising source for bacterial cellulose production. This study aims to observe the influence of TiO2 nanoparticles and graphene on the characteristic of bacterial cellulose acetate-based nanocomposite membranes for bacterial filtration in waters. Bacterial cellulose was produced from the pineapple peel waste using fermentation process. High-pressure homogenization process was applied to reduce bacterial nanocellulose size and esterification process was carried out to produce cellulose acetate. Nanocomposite membranes were synthesized with reinforcement of TiO2 nanoparticles 1 % and graphene nanopowder 1 %. The nanocomposite membrane was characterized using an FTIR, SEM, XRD, BET, tensile testing, and bacterial filtration effectiveness using the plate count method. The results showed that the main cellulose structure was identified at the diffraction angle 22° and the cellulose structure slightly changed at the peak of diffraction angles of 14° and 16°. In addition, the crystallinity of bacterial cellulose increased from 72.5 % to 75.9 %, and the functional group analysis showed that several peak shifts indicated a change in the functional group of membrane. Similarly, the surface morphology of membrane became rougher with the structure of mesoporous membrane. Moreover, adding TiO2 and graphene increases crystallinity and bacterial filtration effectiveness of nanocomposite membrane.