Full physicochemical characterization of malic acid: Emphasis in the potential as food ingredient and application in pectin gels

Ionic-physical-chemical triple cross-linked all-biomass-based aerogel for thermal insulation applications

Aerogels, as a unique porous material, are expected to be used as insulation materials to solve the global environmental and energy crisis. Using chitosan, citric acid, pectin and phytic acid as raw materials, an all-biomass-based aerogel with high modulus was prepared by the triple strategy of ionic, physical and chemical cross-linking through directional freezing technique. Based on this three-dimensional network, the aerogel exhibited excellent compressive modulus (24.89 ± 1.76 MPa) over a wide temperature range and thermal insulation properties. In the presence of chitosan, citric acid and phytic acid, the aerogel obtained excellent fire safety (LOI value up to 31.2%) and antibacterial properties (antibacterial activity against Staphylococcus aureus and Escherichia coli reached 81.98% and 67.43%). In addition, the modified aerogel exhibited excellent hydrophobicity (hydrophobic angle of 146°) and oil-water separation properties. More importantly, the aerogel exhibited a biodegradation rate of up to 40.31% for 35 days due to its all-biomass nature. This work provides a green and sustainable strategy for the production of highly environmentally friendly thermal insulation materials with high strength, flame retardant, antibacterial and hydrophobic properties.

Araticum (Annona crassiflora Mart.): A critical review for the food industry

This review aimed to critically and comparatively analyze the physicochemical, proximate, nutritional, phytochemical composition, and bioactivities of araticum (Annona crassiflora Mart.) (AAc), a fruit from the Brazilian Cerrado. Additionally, the potential applications of this fruit in the food industry were reviewed. Data and information were collected from the Scopus, Web of Science, and Google Scholar databases. AAc, a fruit mainly studied in the Brazilian regions of Minas Gerais and Goiás, has well-documented physicochemical, proximate, and nutritional characteristics. It is rich in fiber, sugars, vitamins A and C, minerals, and oil, making it attractive to the food industry. However, there are research gaps, such as the impact of climatic conditions on the AAc chemical composition. Additional studies are needed, especially for the peel and seeds, and investigations of pre-treatments effect on the chemical composition are recommended. The application of AAc in food products is mainly limited to pulp, but there is potential for using peels and seeds. AAc is a rich source of phytochemical compounds with various biological properties, such as antioxidants, hepatoprotective, and antimicrobial activities. Future studies should explore other phytochemicals present in the fruit beyond phenolic compounds. The consumption of AAc can contribute to combating food insecurity malnutrition, and promoting the conservation of the Brazilian Cerrado.

Strong, tough, high-release, and antibacterial nanocellulose hydrogel for refrigerated chicken preservation

Enormous amounts of food resources are annually wasted because of microbial contamination, highlighting the critical role of effective food packaging in preventing such losses. However, traditional food packaging faces several limitations, such as low mechanical strength, poor fatigue resistance, and low water retention. In this study, we aimed to prepare nanocellulose hydrogels with enhanced stretchability, fatigue resistance, high water retention, and antibacterial properties using soy hull nanocellulose (SHNC), polyvinyl alcohol (PVA), sodium alginate (SA), and tannic acid (TA) as raw materials. These hydrogels were applied in food packaging to extend the shelf life of refrigerated chicken. The structure and properties (e.g., mechanical, antibacterial, and barrier properties) of these hydrogels were characterized using different techniques. Fourier-transform infrared spectroscopy revealed the presence of hydrogen and ester bonds in the hydrogels, whereas scanning electron microscopy revealed the three-dimensional network structure of the hydrogels. Mechanical testing demonstrated that the SHNC/PVA/SA/TA-2 hydrogel exhibited excellent tensile properties (elongation = 160 %), viscoelasticity (storage modulus of 1000 Pa), and mechanical strength (compressive strength = 10 kPa; tensile strength = 0.35 MPa). Moreover, under weak acidic and alkaline conditions, the ester bonds of the hydrogel broke down with an increase in pH, improving its swelling and release properties. The SHNC/PVA/SA/TA-2 hydrogel displayed an equilibrium swelling ratio exceeding 300 %, with a release rate of >80 % for the bioactive substance TA. Notably, antibacterial testing showed that the SHNC/PVA/SA/TA-2 hydrogel effectively deactivated Staphylococcus aureus and Escherichia coli, prolonging the shelf life of refrigerated chicken to 10 d. Therefore, the SHNC/PVA/SA/TA hydrogels can be used in food packaging to extend the shelf life of refrigerated meat products. Their cost-effectiveness and simple preparation make them suitable for various applications in the food industry.

Enhancing l-Malic Acid Production in Aspergillus niger via Natural Activation of sthA Gene Expression

The efficient production of l-malic acid using Aspergillus niger requires overcoming challenges in synthesis efficiency and excessive byproduct buildup. This study addresses these hurdles, improving the activity of NADH-dependent malate dehydrogenase (Mdh) in the early stages of the fermentation process. By employing a constitutive promoter to express the Escherichia coli sthA responsible for the transfer of reducing equivalents between NAD(H) and NADP(H) in A. niger, the l-malic acid production was significantly elevated. However, this resulted in conidiation defects of A. niger, limiting industrial viability. To mitigate this, we discovered and utilized the PmfsA promoter, enabling the specific expression of sthA during the fermentation stage. This conditional expression strain showed similar phenotypes to its parent strain while exhibiting exceptional performance in a 5 L fermenter. Notably, it achieved a 65.5% increase in productivity, reduced fermentation cycle by 1.5 days, and lowered succinic acid by 76.2%. This work marks a promising advancement in industrial l-malic acid synthesis via biological fermentation, showcasing the potential of synthetic biology in A. niger for broader applications.

Product contamination during mechanochemical synthesis of praziquantel co-crystal, polymeric dispersion and cyclodextrin complex

This paper aims to evaluate the product contamination by elemental impurities during the mechanochemical synthesis of praziquantel (PZQ) co-crystal, polymeric dispersion and cyclodextrin complex by grinding. To assess that, PZQ was co-ground with malic acid (MA), Poloxamer F-127 (F-127) and hydroxypropyl-β-cyclodextrin (HPβCD) in high-energy vibrational mills using stainless steel and agate grinding tools, applying different processing time (30 and 90 min). Differential scanning calorimetry and X-ray powder diffraction confirmed the formation of the targeted products, regardless of applied processing time and grinding tool type. After digestion of the solid powder products, the levels of selected elemental impurities were analysed by inductively coupled plasma mass spectrometry (ICP-MS). The analysis revealed that the content of Mg, Ca, and V are below the limit of quantification in all samples analysed. The contents of P and Na are not related to the type of ball mill and reaction time, but to the starting materials themselves, considering that Na is found in HPβCD and MA, while P was found in F-127. The detected Si impurities in the co-ground products can be related to the use of the agate balls and jars, while the presence of Cr and Fe can be related to the use of the stainless steel grinding tools. The risk assessment showed that the oral administration of the prepared co-ground products in quantities corresponding to regular PZQ oral doses resulted in only insignificant exposure to Cr. Finally, the use of agate grinding tools should be preferred, as administration of such products results in lower Cr exposure. The presented elemental impurities did not lead to any significant drug degradation as PZQ content at the end of the six-month testing period was still in the range of 95-105 % of the initial content. Regardless, ICP-MS analysis of the elemental impurities should be considered in regular quality control procedures in the development and production of novel pharmaceutical products prepared by grinding.

Pectin extracted from Premna Microphylla Turcz for preparation of a "sandwich" multi-property sensor film involved with deep eutectic solvent

An acidic deep eutectic solvent (DES, choline chloride/citric acid) was used to efficiently extract edible pectin from Premna microphylla Turcz (PMTP) and further prepare the film sensor with the purpose of "four birds with one stone" with the roles of extractant, coalescent, conductivity promoter and bacteriostatic agent. The optimized extraction process accorded with pseudo second-order kinetics, which was carried out at 78.2 °C for 1.29 h with the solid-liquid ratio of 1:34.66 g/mL with the yield up to 0.8210 g/g. After comprehensive characterizations of pectin product, a simple casting method was used to prepare the PMTP-DES based composite film. It showed that the composite film has promising compatibility, smooth surface, good breathability and ideal homogeneity. After 30 power on/power off cycles at 10 V, it exhibited satisfied conductivity stability. Moreover, the PMTP-DES film could be simply assembled as the flexible visual temperature sensor, with sensitive response at breathing or finger touch; it exhibited the highest sensitivity of 134 %/°C when the external temperature changed from 15 to 55 °C. Besides, the composite film also has preferable antimicrobial activity. The whole results and findings were aimed to contribute for the raw material, composition, preparation, and functions of the existing flexible functional materials.

Erosive potential of vitamin waters, herbal drinks, carbonated soft drinks, and fruit juices on human teeth: An in vitro investigation

Background

Dental erosion is the loss of dental hard tissues through the acid dissolution of tooth minerals. One of the major factors that cause erosion is the consumption of acidic food and drinks. This study investigated and compared the effect of vitamin waters, herbal beverages, carbonated soft drinks, and fruit juices on the loss of human dental hard tissue.

Methods

Human tooth samples were immersed in various drinks: vitamin waters, herbal beverages, carbonated soft drinks, and fruit juices. The pH value of each drink was measured using a pH meter. The weight of each sample was determined before and after six days of immersion in the tested drink, and the weight loss percentage was calculated. The exposed tooth surfaces were also examined under a scanning electron microscope.

Results

Most of the tested drinks were acidic and displayed pH values lower than the critical pH for enamel erosion. Significant weight loss of the tooth samples was found in all tested drink groups. Additionally, the samples immersed in fruit juices and herbal beverages exhibited significantly greater weight loss than those immersed in carbonated soft drinks. Scanning electron micrographs showed samples immersed in the tested drinks to demonstrate structural disintegration with occasional void spaces, except for samples immersed in Doi Kham® Lemongrass drink.

Conclusion

Most of the tested drinks have the potential to cause dissolution and destruction of dental hard tissues. Consumers should be aware that prolonged exposure to these drinks could lead to permanent loss of tooth mineral and dental erosion.

Powdered Beverage from Native Plants from Argentina (Zuccagnia punctata and Solanum betaceum) Obtained by Spray-Drying: A Promising Source of Antioxidant Compounds

In previous studies, the Argentinean native plants called Zuccagnia punctata (jarilla, pus pus, lata) and Solanum betaceum (chilto, tree tomato) were reported as new natural sources of antioxidant compounds, mainly chalcones, anthocyanins and rosmarinic acid derivates. The present study deals with the production of antioxidant beverages of Z. punctata (Zp) extract and chilto juice with honey as sweetener. A Zp extract and red chilto juice were obtained according to Food Code and characterized. The beverages were formulated by using maltodextrin (MD) with two dextrose equivalents (DE), 10 and 15, and then spray-dried at an inlet air temperature of 130 °C. The physicochemical, microscopical, phytochemical and functional characteristics of the powders were surveyed. The experiments carried out showed good physical properties for both formulations showing high water solubility with adequate features for handling, transport and storage. The chromatic parameters of both powdered beverages indicate orange-pink tones regardless of the wall material used. The total polyphenol and flavonoid content in the beverages were kept after spray-drying (92 and 100%, respectively). The anthocyanins were less stable under drying conditions (yield 58%). Both powdered beverages showed high scavenger capacity on ABTS^•+, HO^• and H₂O₂ (SC₅₀ between 3.29 to 41.05 µg GAE/mL) and were able to inhibit xanthine oxidase (XOD) activity (CI₅₀ between 91.35 and 114.43 µg GAE/mL). The beverages were neither toxic nor mutagenic in the concentration range with biological activity. The results obtained in the present work scientifically support the use of the powdered beverages of Argentinean native plants as antioxidant.

Synergistic Antimicrobial Activity of Magnetite and Vancomycin-Loaded Mesoporous Silica Embedded in Alginate Films

The aim of the present study was to obtain a hydrogel-based film as a carrier for the sustained and controlled release of vancomycin, an antibiotic commonly used in various types of infections. Considering the high-water solubility of vancomycin (>50 mg/mL) and the aqueous medium underlying the exudates, a prolonged release of vancomycin from an MCM-41 carrier was sought. The present work focused on the synthesis of malic acid coated magnetite (Fe3O4/malic) by co-precipitation, synthesis of MCM-41 by a sol-gel method and loading of MCM-41 with vancomycin, and their use in alginate films for wound dressing. The nanoparticles obtained were physically mixed and embedded in the alginate gel. Prior to incorporation, the nanoparticles were characterized by XRD, FT-IR and FT-Raman spectroscopy, TGA-DSC and DLS. The films were prepared by a simple casting method and were further cross-linked and examined for possible heterogeneities by means of FT-IR microscopy and SEM. The degree of swelling and the water vapor transmission rate were determined, considering their potential use as wound dressings. The obtained films show morpho-structural homogeneity, sustained release over 48 h and a strong synergistic enhancement of the antimicrobial activity as a consequence of the hybrid nature of these films. The antimicrobial efficacy was tested against S. aureus, two strains of E. faecalis (including vancomycin-resistant Enterococcus, VRE) and C. albicans. The incorporation of magnetite was also considered as an external triggering component in case the films were used as a magneto-responsive smart dressing to stimulate vancomycin diffusion.

High-Release, Residue-Free Polysaccharide Hydrogel for Refrigerated Food Preservation

Hundreds of millions of tons of food resources are wasted annually due to microbial contamination. Effective food packaging can prevent food contamination and wastage. However, traditional food packaging has the problem of low release of bioactive substances. This study aimed to prepare a pH-responsive polysaccharide hydrogel (GDPP) by double cross-linking of ester and hydrogen bonds that could result in a high release of bioactive substances and no residual peeling. The infrared results showed the existence of ester bonds in the hydrogel, and the scanning electron microscopy results showed the porous network structure of the hydrogel. The results of texture profile analysis and self-healing tests showed that GDPP-1 has good mechanical and self-healing properties. Moreover, the ester bond of the hydrogel broke in response to the pH in the environment, improving the swelling and release properties of the hydrogel. The equilibrium swelling ratio of GDPP-1 was greater than 1000%, and the release rate of bioactive substances was more than 80%. Notably, the results of peeling experiments showed that only 0.1 N external force was needed to separate the hydrogel from the salmon, and no residue was observed on the salmon surface. The final freshness test results showed that the hydrogel effectively prolonged the shelf life of refrigerated salmon for 3-6 days. These findings indicated that hydrogels could be used in food packaging to extend the shelf life of refrigerated food. Furthermore, their advantages of low cost and simple preparation can better meet the needs of food industry applications.

Antimicrobial Resistance and Recent Alternatives to Antibiotics for the Control of Bacterial Pathogens with an Emphasis on Foodborne Pathogens

Antimicrobial resistance (AMR) is one of the most important global public health problems. The imprudent use of antibiotics in humans and animals has resulted in the emergence of antibiotic-resistant bacteria. The dissemination of these strains and their resistant determinants could endanger antibiotic efficacy. Therefore, there is an urgent need to identify and develop novel strategies to combat antibiotic resistance. This review provides insights into the evolution and the mechanisms of AMR. Additionally, it discusses alternative approaches that might be used to control AMR, including probiotics, prebiotics, antimicrobial peptides, small molecules, organic acids, essential oils, bacteriophage, fecal transplants, and nanoparticles.

Opuntia ficus-indica Fruit: A Systematic Review of Its Phytochemicals and Pharmacological Activities

The use of Opuntia ficus-indica fruits in the agro-food sector is increasing for a multiplicity of players. This renewed interest is, in part, due to its organoleptic characteristics, nutritional value and health benefits. Furthermore, industries from different sectors intend to make use of its vast array of metabolites to be used in different fields. This trend represents an economic growth opportunity for several partners who could find new opportunities exploring non-conventional fruits, and such is the case for Opuntia ficus-indica. O. ficus-indica originates from Mexico, belongs to the Cactaceae family and is commonly known as opuntia, prickly pear or cactus pear. The species produces flowers, cladodes and fruits that are consumed either in raw or in processed products. Recent publications described that consumption of the fruit improves human health, exhibiting antioxidant activity and other relevant pharmacological activities through enzymatic and non-enzymatic mechanisms. Thus, we provide a systematic, scientific and rational review for researchers, consumers and other relevant stakeholders regarding the chemical composition and biological activities of O. ficus-indica fruits.

The Effect of Berry Pomace on Quality Changes of Beef Patties during Refrigerated Storage

This study aims to evaluate the ability of raspberry and blackberry pomace to inhibit lipid oxidation and prolong the refrigerated storage of beef patties. Berry pomace was incorporated into beef patties at the concentration of 1, 3, and 5%. Packed patties were stored for 9 days at 4 °C temperature and the quality of the meat was evaluated on the 0, 3rd, 6th, and 9th day. The natural mass loss during storage, the pH as well as the lipid oxidation were evaluated by thiobarbituric acid-reactive substance (TBARS) method. GC was used to determine the amount of fatty acids and e-nose, based on ultrafast gas chromatography, was used for the determination of volatile organic compounds in beef patties before and after the storage. The highest mass loss during refrigerated storage was observed in the control beef patties, while the berry pomace absorbed water and reduced the loss. The pomace additive influenced the decrease in the patties pH during the storage. Berry pomace can be very effective in relation to lipid oxidation, and as little as 1% of berry pomace influenced the decrease in the TBAR’s values in the patties stored for nine days by 3.06 and 2.42 times, depending on the pomace compared to the control patties. The use of berry pomace in meat products can reduce lipid oxidation, increase their fiber content and act as a thickener, as well as contribute to the usage of agri-food by-products.

Performance of broiler chicken on dietary supplementation of protected organic acids blend

1. The fatty acid coated organic acids blend was evaluated for its potential as a growth promoter.2. A six-week experiment was conducted following a completely randomised design. One-day old broiler chicks (n=384) were randomly divided into four dietary groups (eight replicates per group). Diet treatments were an unsupplemented basal diet or containing 0.3, 0.6, and 1 g/kg of a coated organic acid blend. Birds were evaluated for growth performance, carcass traits, immune-competence, total viable count, and gut villus height.3. The broiler chickens fed with 1 g/kg organic acids blend showed significantly higher body weight gain with improved feed conversion ratio and lower mortality than those fed the basal diet.4. The carcass traits vis. eviscerated yield, dressing percentage, breast yield and relative weight of giblets, were significantly better in the group fed with 1 g/kg coated organic acids blend with reduction in abdominal fat.5. Significantly higher cell-mediated, humoral immune responses and villi height with higher lymphoid organ weight (bursa and thymus) and a significant decrease in the total viable count were recorded in birds fed 1 g/kg organic acids blend.6. The results indicated that dietary inclusion of coated organic acids blend (1 g/kg) improved growth performance, carcass traits, immunity, and gut health in broiler chicken and reduced total viable count and abdominal fat, indicating its potential role as a promising growth promoter in poultry.

The effect of different chelators on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow

The aim of this study was to investigate the influence of various irrigants on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow to root dentin. Three slices (1.0 ± 0.1 mm) were prepared from the middle third of 20 human maxillary anterior teeth. On each dentin disc, three perpendicular simulated perforation holes with a standardized 0.8 mm diameter were created. The sections from the same root were distributed arbitrarily into three groups (n = 20) for smear layer removal procedure: ethylenediaminetetraacetic acid (EDTA), chitosan-based silver nanoparticles (AgNPs-chitosan), and maleic acid (MA). Afterwards, the holes were randomly filled with one of the three investigated cements. The samples were submitted to the push-out test using a universal measuring system. Kruskal-Wallis and Mann-Whitney U tests were used to assess statistical differences among the groups. When the results were evaluated, it was found that the types of cement and chelating agents significantly affected the dislocation resistance (P < 0.05). EDTA provided a higher dislocation resistance with the investigated cements in comparison to MA and AgNPs-chitosan (P < 0.05). Furthermore, it was observed that MTA Flow and MTA Angelus presented improved dislocation resistance values than the MTA Repair HP when used with EDTA (P < 0.05). The findings indicated that EDTA increased the dislodgement resistance of the investigated cements. In conclusion, when EDTA used, MTA Flow, and MTA Angelus showed higher dislocation resistance values.

Evaluation of easy-removing antioxidant films of chitosan with Melaleuca alternifolia essential oil

Chitosan - tea tree essential oil (TTEO) films were obtained as a new biodegradable material. Malic acid or lactic acid solvents were evaluated to obtain easy-removing films. The microstructure by SEM and FT-IR, the thermal properties by TGA/DSC, the mechanical properties, the water vapor permeability, the antioxidant (DPPH^• and ABTS^•+) activity and the optical properties of the formulated films were evaluated. A complete dissolution of the film in water was obtained. The elongation to break was higher in the films with malic acid (145.88-317.33%), comparing with those with lactic acid (25.54-44.08%). Chitosan film obtained in malic acid with TTEO showed the highest antioxidant activity. The colour and transparency of the samples did not suffer significant variations by TTEO addition. Films showed good UV-barrier properties, with a slightly improvement by TTEO addition. The films obtained showed a great potential for food packaging applications.