Longer Storage Periods Research Articles

Estimating the Physicochemical and Antioxidant Properties of Hardy Kiwi (Actinidia arguta) Treated with 1-Methylcyclopropene during Storage

In fruit storage, new methods are being sought to extend the distribution period while maintaining the highest quality parameters of the fruit, i.e., the physical and chemical characteristics of the fruit, but also the health-promoting properties. One method is to treat the fruit with 1-MCP, which effectively inhibits fruit ripening, since the main reasons for limiting the distribution of minikiwi fruit are rapid ripening and the loss of firmness. It is also highlighted that minikiwi is a source of antioxidants, which, as highly reactive compounds, are quickly degraded during storage. This study evaluates the effectiveness of using 1-MCP to reduce minikiwi softening and maintain the high antioxidant properties of the fruit. In the experiment, minikiwi fruits of the ‘Ananasnaya’ cultivar were used. After harvesting, the fruits were treated with 1-methylcyclopropene at a concentration of 0.65 µL/L. Fruits treated in this way were stored in ordinary cold storage (NA) and under low oxygen concentration (ULO) conditions for a period of 12 weeks. The fruits’ physicochemical properties, sugar and acid contents and antioxidant potential, which consisted of ascorbic acid, polyphenols, phenolic acids, flavonols and flavan-3-ols, were evaluated. The application of 1-MCP is effective in reducing the loss of firmness in the minikiwi during storage, but the blocking of minikiwi ripening by 1-MCP makes the fruit less sweet and more acidic. Fruits treated with 1-MCP had higher antioxidant activity and a higher content of biologically active compounds. The effect of 1-MCP is stronger for flavan-3-ols, but slightly weaker for phenolic acids. Fruits treated with 1-MCP have a higher antioxidant potential than untreated fruit after a long period of storage.

FAKTOR-FAKTOR YANG MEMPENGARUHI HARGA JUAL KARET DI DESA KEBUNJATI DI KECAMATAN SEMIDANG AJI KABUPATEN OKU

This study has directions to find out the factors that influence the selling price of rubber in Kebunjati Village, Semidang Aji District, OKU Regency. This research method was carried out using a quantitative method in which the research used multiple linear regression analysis. Data was obtained by distributing questionnaires and data obtained from rubber farmers in Kebunjati Village. The results of this study are the factors that influence the selling price of rubber in Kebunjati Village, namely there are 3 factors including: place of sale, rubber quality and slab storage time. Of the three factors that greatly influence, namely the place of sale and the quality of rubber with a significant level of 1% and one factor that has a significant effect on the selling price of rubber in Kebunjati Village, namely the long period of storage of slabs with a significant level of 30%.

Stability of pesticide residues in citrus fruits during storage

Introduction. Storage of selected samples before transportation to the laboratory and immediately before analysis is an important component in the process of product quality control and evaluation.
 Purpose of the work was to evaluate the degradation of pesticide active substances in real samples of citrus fruit left for long periods of storage in deep freezing conditions.
 Materials and methods. High-performance liquid chromatography with triple quadrupole mass detector (HPLC-MS/MS) was used to identify and quantify pesticide active substances. According to the method of analysis MUK 4.1.3657–20, cryogenic grinding of samples was carried out in a cutter using dry ice. Sample preparation was carried out using the QuEChERS technology. To extract analytes from a homogenized sample acetonitrile was used in the presence of salts containing citrate buffer, followed by purification of the extract by SPE.
 Results. In the studied samples of citrus, the analytes showed stability. Thirty months after storage of samples in deep freezing conditions (temperature not higher than –20 °C), the identified levels of active ingredients of the pesticides imazalil, pyrimethanil and prochloraz did not change by more than 20% compared to the previously detected concentrations. Insignificant amounts of imidacloprid, thiabendazole and pyriproxyfen, as well as traces of azoxystrobin and trifloxystrobin, detected in the study of samples, were also found in samples after long-term storage. 
 Limitation. The study is limited to the study of the stability of individual active substances found in real samples of citrus fruits intended for sale to the consumer.
 Conclusion. Proper storage of samples should ensure the preservation of the levels of active substances in the samples and exclude their change due to various processes (volatilization, enzymatic and hydrolytic decomposition, etc.), which requires the performance of preliminary experimental studies to assess their stability. The work showed the stability of residual quantities of imazalil, pyrimethanil, prochloraz, imidacloprid, thiabendazole, and pyriproxyfen in citrus fruit matrices under storage conditions in a freezer at not more than –20 °C for 30 months.

Impact of media culture, freeze-drying and storage conditions on preservation of Lacticaseibacillus paracasei 90: Viability and metabolic potential as a secondary culture in semi-hard cheese

Freeze-drying is the main process used to preserve lactic bacterial cultures at an industrial level; however, their viability and metabolic activity can be affected not only by the process per se but also by storage conditions. This study investigated the effect of freeze-drying and long-term storage (14 months) on the viability and metabolic activity of Lacticaseibacillus paracasei 90 (L90) grown in three culture media. The freeze-drying process did not influence its culturability and viability, regardless of the culture media used. The storage of the freeze-dried cultures at room temperature had a negative impact on viability, culturability and its ability to grow and acidify milk. However, L90 was able to withstand a long period of storage at low temperatures (14 months, 4 °C) and keep the technological features desirable of a ripening culture. Overall, the results demonstrate the robustness of this strain as a secondary culture in the food industry.

A comprehensive quality evaluation method of different medicinal parts of Physalis Calyx seu Fructus by fingerprints, chemometrics, antioxidant activity, network pharmacology and molecular docking.

Physalis Calyx seu Fructus (PCF) is a herb widely used in China for its function of clearing heat and detoxifying, benefitting the pharynx and reducing phlegm, both in health care and in tea drinking. However, the quality of its fruit and calyx is uneven and the storage period is short. Therefore, it is crucial to develop other parts of PCF with longer storage periods and obvious medicinal effects. Firstly, high-performance liquid chromatography was used to develop the fingerprint of different parts of PCF, and various chemometric analyses were conducted to screen out chemical markers. The calyxes of PCF were found to cluster together, distinct from the fruits, roots, stems and leaves. The active components of PCF were concentrated in the persistent calyxes, and flavonoids were mainly found in the persistent calyxes and leaves. Secondly, the extraction of persistent calyxes showed the strongest scavenging ability of DPPH and ABTS. Finally, the important chemical markers were verified by network pharmacological analysis and molecular docking. It provides a reference for the clinical application of PCF, and the obtained chemical markers offer a scientific basis for quality evaluation.

Methods for Long-Term Storage of Pure Cultures of Macrofungi

Basidiomycetous macrofungi have significant biotechnological potential and are promising objects for use in va-rious industrial sectors, such as food production, pharmaceuticals, the production of active compounds and polysaccharides. The industrial use of macrofungi implies the presence of large collections of cultures using sto-rage protocols that ensure the preservation of viability, reproduction, genetic stability and the ability to produce active compounds. With the expansion of the list of industrially used species, it is advisable to develop new protocols for the storage of strains and optimize the existing ones for new, promising types of macrofungi. It seems necessary to study in detail the effect of long periods of storage on morphological and cultural characteristics, genetic stability, enzymatic activity, and the ability to form sexual structures.

Microbial and chemical stability of Acheta domesticus powder during one year storage period at room temperature

The sustainability of food systems is of growing concern worldwide, so insects are a growing source of animal proteins for food and feed. Among insect species, the house cricket, Acheta domesticus, is a promising option from a sustainability point of view. This study aimed at evaluating both microbiological and chemical stability of A. domesticus powders during one year of storage at room temperature. Our study was conducted on cricket powders obtained by three different processes: drying at 80°C (P80), drying at 120°C (P120), and lyophilization (PL). Regarding microbiological profile, the pathogens Listeria monocytogenes and Salmonella were not detected, while total viable count and lactic acid bacteria tended to decrease during the storage period. Bacillus cereus was detected at low counts during the entire storage period, but only one replicate of P80 exceeded the limit set for A. domesticus by the European Commission Implementing Regulation 2017/2470. The measured protein contents of the cricket powders immediately after production ranged between 60.6 and 64.3%. The peroxide values were far higher than the limit established by the EU Regulation in all samples. Higher amounts of hexanal and pentanal were detected in P80 and P120 than in PL, indicating that oven drying could enhance lipid oxidation. In conclusion, a one year shelf-life can suitably be ascribed to the analyzed cricket powders from a microbiological point of view, but lacked chemical stability and had a clear early tendency toward rancidity. The samples dried at 120°C and lyophilized never exceeded the limit set by European Commission for B. cereus count in A. domesticus powder. In addition, lyophilized samples showed the lowest values of hexanal and pentanal, the aldehydes that are primarily responsible for the rancid smell. The oxidative status of the final products could be strongly influenced by the powder processing, so for this reason, edible insect species-specific post-rearing protocols should be implemented. These results open an interesting scenario for a long period of storage of insect powder in the absence of a cold chain, making the insect market an increasingly sustainable sector.

Molecular pathology quality control in Southeast Asia: Results of a multiregional quality assurance study from MASTER KEY Asia.

Tissue specimen quality assurance is a major issue of precision medicine for rare cancers. However, the laboratory standards and quality of pathological specimens prepared in Asian hospitals remain unknown. To understand the methods in Southeast Asian oncology hospitals and to clarify how pre-analytics affect the quality of formalin-fixed paraffin-embedded (FFPE) specimens, a questionnaire surveying pre-analytical procedures (Part I) was administered, quality assessment of immunohistochemistry (IHC) staining and DNA/RNA extracted from the representative FFPE specimens from each hospital (Part II) was conducted, and the quality of DNA/RNA extracted from FFPE of rare-cancer patients for genomic sequencing (Part III) was examined. Quality measurements for DNA/RNA included ΔΔCt, DV200, and cDNA yield. Six major cancer hospitals from Malaysia, Philippines, and Vietnam participated. One hospital showed unacceptable quality for the DNA/RNA assessment, but improved by revising laboratory procedures. Only 57% (n= 73) of the 128 rare-cancer patients' specimens met both DNA and RNA quality criteria for next-generation sequencing. Median DV200 was 80.7% and 64.3% for qualified and failed RNA, respectively. Median ΔΔCt was 1.25 for qualified and 4.89 for failed DNA. Longer storage period was significantly associated with poor DNA (fail to qualify ratio=1579:321 days, p< 0.001) and RNA (fail to qualify ratio=1070:280 days, p< 0.001). After improvement of pre-analytical factors, the qualification rate increased for hospitals A and E from 41.5% to 70.5% and 62.5% to 86%, respectively. This is the first report to elucidate the pre-analytical laboratory procedures of main Southeast Asian oncology hospitals. An external quality assessment program may improve factors associated with tumor FFPE specimen quality.

Selection improvement of apple tree assortment for southern horticulture

The paper presents the results of a long-term test of eight scab-immune apple varieties of domestic and foreign breeding under the conditions of North Caucasus region of Russia. The study was aimed at improving the assortment of apple trees in the Southern region of Russia on the basis of a comprehensive assessment of promising varieties of domestic and foreign breeding. The study objects included scab-immune apple varieties (Malus x domestica Borkh.) of various ecological and genetic origin: Carmen, Nika, Orphey and Margo (North Caucasian Federal Scientific Center of Horticulture, Viticulture, Wine-making together with Nationwide Research Institute for Horticultural Breeding, Russia), Mikhsan and Zarya Stavropoliya (Stavropol Experimental Horticulture Station together with Nationwide Research Institute for Horticultural Breeding, Russia), Modi (Italy), Florina (France). The common and up-to-date breeding programs and techniques developed with the assistance of Nationwide Research Institute for Horticultural Breeding were applied. Based on the long-term results of ecological testing of new scab-immune apple varieties of different origins under the conditions of the Republic of North Ossetia-Alania and Krasnodar Krai, the most valuable varieties for industrial use and for breeding process were identified. The following varieties were identified as promising for industrial use and breeding: varieties with a late flowering time – Margo and Orphey; varieties with a high average flowering score (4.5–5.0 points): Carmen, Modi, Orphey, Nika, Florina, Margo. It was found that all investigated varieties of apple trees can be attributed to the annual fruit-bearing; the periodicity of fruiting varied within 22.6–28.8 %. In 2020, in the conditions of North Ossetia-Alania the maximum yield was observed for the following scab-immune varieties: Margo (24.1 t/ha) and Modi (25.2 t/ha) on rootstock СK2; Mikhsan (19.2 t/ha) and Nika (20.6 t/ha) on rootstock MM106. In order to improve the assortment of the Southern region of Russia and to create modern intensive orchards, new varieties of apple of domestic breeding were recommended: Margo, Nika, Orphey and Modi (foreign breeding), which have high productivity, immunity to scab (based on Rvi-6 gene), better commerciality and a long period of fruit storage.

Immobilization of Alpha Acetolactate Decarboxylase in Hybrid Gelatin/Alginate Support for Application to Reduce Diacetyl Off-Flavor in Beer

Beer production is the largest among alcoholic beverages. Its production process is complex and demands several steps. Lager beers commonly present an off-flavor of butter that is due to the presence of diacetyl, and to avoid such a problem, a long period of maturation (3–5 weeks) is required. Another way is the application of (α-acetolactate decarboxylase) ALDC to accelerate the process. The objectives of the present work were to develop a low-cost support using gelatin, a residue from capsules from the nutraceutical industry, to immobilize the ALDC enzyme. For this, the yield, efficiency and activity recovered, and the stability of free and immobilized enzymes at different temperatures and pH were evaluated. To evaluate the capacity of immobilized enzymes when applied directly to beer and their operational stability, three concentrations of glutaraldehyde (1%, 2.5% and 5%) were tested in distilled water as a cross-linking agent. The best results obtained were 95.6%, 27.0% and 23.6%, respectively, for yield, efficiency and activity recovery. Immobilization provided a high activity over a wide pH range. The immobilized enzyme showed greater stability at temperatures of 50 and 60 °C. The immobilized derivative showed adequate reuse capacity, and its dehydrated form had excellent activity after long periods of storage.

Nanostructured Lipid Carriers Aimed to the Ocular Delivery of Mangiferin: In Vitro Evidence

Although mangiferin (MGN) is a natural antioxidant that could be a good candidate for the treatment of ocular diseases, its use in ophthalmology is strongly compromised due to its high lipophilicity. Its encapsulation in nanostructured lipid carriers (NLC) seems to be an interesting strategy for improving its ocular bioavailability. As reported in our previous work, MGN-NLC showed high ocular compatibility and fulfilled the nanotechnological requirements needed for ocular delivery. The aim of the present work was to investigate, in vitro and ex vivo, the capability of MGN-NLC to act as a potential drug delivery system for MGN ocular administration. The data obtained in vitro on arising retinal pigment epithelium cells (ARPE-19) did not show cytotoxic effects for blank NLC and MGN-NLC; likewise, MGN-NLC showed the maintenance of the antioxidant role of MGN by mitigating ROS (Reactive Oxygen Species) formation and GSH (glutathione) depletion induced by H2O2. In addition, the capacity of MGN-released to permeate through and accumulate into the ocular tissues was confirmed ex vivo using bovine corneas. Finally, the NLC suspension has been formulated as a freeze-dried powder using mannitol at a concentration of 3% (w/v) in order to optimize its storage for long periods of time. All this evidence suggests a potential application of MGN-NLC in the treatment of oxidative stress-related ocular diseases.

Effects of Long-Term Storage on the Biobanked Neonatal Dried Blood Spot Metabolome.

Over 2.5 million neonatal dried blood spots (DBS) are stored at the Danish National Biobank. These samples offer extraordinary possibilities for metabolomics research, including prediction of disease and understanding of underlying molecular mechanisms of disease development. Nevertheless, Danish neonatal DBS have been little explored in metabolomics studies. One question that remains underinvestigated is the long-term stability of the large number of metabolites typically assessed in untargeted metabolomics over long time periods of storage. Here, we investigate temporal trends of metabolites measured in 200 neonatal DBS collected over a time course of 10 years, using an untargeted liquid chromatography tandem mass spectrometry (LC-MS/MS) based metabolomics protocol. We found that a majority (71%) of the metabolome was stable during 10 years of storage at -20 °C. However, we found decreasing trends for lipid-related metabolites, such as glycerophosphocholines and acylcarnitines. A few metabolites, including glutathione and methionine, may be strongly influenced by storage, with changes in metabolite levels up to 0.1-0.2 standard deviation units per year. Our findings indicate that untargeted metabolomics of DBS samples, with long-term storage in biobanks, is suitable for retrospective epidemiological studies. We identify metabolites whose stability in DBS should be closely monitored in future studies of DBS samples with long-term storage.

The Stability Study of Electrochemical Aptasensor to Detect SARS-CoV-2 Spike Protein and Its Application for Clinical Samples of Nasopharyngeal Swab

The stability characteristics associated with the shelf life of a biosensor are rarely investigated, however, they are important factors for real applications. Stability is the variation in the detection signal over a long period of storage. This study aims to determine the effect of storage time on the stability of SARS-CoV-2 receptor binding domain (RBD) spike protein aptamers related to shelf life and the performance of an electrochemical aptasensor on clinical samples. The research method includes a stability study conducted using the accelerated stability method based on the Arrhenius equation at three variations of temperature and storage time. The electrochemical aptasensor's performance was evaluated on clinical samples of 32 nasopharyngeal swabs at biosafety level 3 and its potential on clinical saliva samples. The results indicated that the developed electrochemical aptasensor was stable for ± 15 days with a shelf life of 18, 17 and 16 days, respectively, at 25, 40 and 50 °C. This electrochemical aptasensor has the potential to be a Point of Care (POC) device for the clinical detection of SARS-CoV-2 because it can be tested on clinical samples of nasopharyngeal swabs and the results show its potential application to detect in clinical saliva samples.

Anaerobic Storage Completely Removes Suspected Fungal Pathogens but Increases Antibiotic Resistance Gene Levels in Swine Wastewater High in Sulfonamides.

Wastewater storage before reuse is regulated in some countries. Investigations of pathogens and antibiotic resistance genes (ARGs) during wastewater storage are necessary for lowering the risks for wastewater reuse but are still mostly lacking. This study aimed to investigate pathogens, including harmful plant pathogens, and ARGs during 180 d of swine wastewater (SWW) storage in an anaerobic storage experiment. The contents of total organic carbon and total nitrogen in SWW were found to consistently decrease with the extension of storage time. Bacterial abundance and fungal abundance significantly decreased with storage time, which may be mainly attributed to nutrient loss during storage and the long period of exposure to a high level (4653.2 μg/L) of sulfonamides in the SWW, which have an inhibitory effect. It was found that suspected bacterial pathogens (e.g., Escherichia-Shigella spp., Vibrio spp., Arcobacter spp., Clostridium_sensu_stricto_1 spp., and Pseudomonas spp.) and sulfonamide-resistant genes Sul1, Sul2, Sul3, and SulA tended to persist and even become enriched during SWW storage. Interestingly, some suspected plant fungal species (e.g., Fusarium spp., Ustilago spp. and Blumeria spp.) were detected in SWW. Fungi in the SWW, including threatening fungal pathogens, were completely removed after 60 d of anaerobic storage, indicating that storage could lower the risk of using SWW in crop production. The results clearly indicate that storage time is crucial for SWW properties, and long periods of anaerobic storage could lead to substantial nutrient loss and enrichment of bacterial pathogens and ARGs in SWW.

Development of Stable Pickering Emulsions with TEMPO-Oxidized Chitin Nanocrystals for Encapsulation of Quercetin.

Pickering emulsions stabilized by TEMPO-oxidized chitin nanocrystals (T-ChNCs) were developed for quercetin delivery. T-ChNCs were synthesized by TEMPO oxidation chitin and systematically characterized in terms of their physicochemical properties. T-ChNCs were rod-like with a length of 279.7 ± 11.5 nm and zeta potential around -56.1 ± 1.6 mV. The Pickering emulsions were analyzed through an optical microscope and CLSM. The results showed that the emulsion had a small droplet size (972.9 ± 86.0 to 1322.3 ± 447.7 nm), a high absolute zeta potential value (-48.2 ± 0.8 to -52.9 ± 1.9 mV) and a high encapsulation efficiency (quercetin: 79.6%). The emulsion stability was measured at different levels of T-ChNCs and pH values. The droplet size and zeta potential decreased with longer storage periods. The emulsions formed by T-ChNCs retarded the release of quercetin at half rate of that of the quercetin ethanol solution. These findings indicated that T-ChNCs are a promising candidate for effectively stabilizing Pickering emulsions and controlling release of quercetin.

Numerical analysis on lunar heat storage system: Multi-objective optimization, heat storage capacity, and thermal insulation performance

The long lunar night of 14 earth days without solar radiation has become the biggest obstacle to the continuous energy supply system day and night. The lunar base heat storage system is one of the best solutions because it is possible to transfer energy from day to night for power generation. However, due to the diversity of energy demands of the lunar base, it is inevitable to study the thermal storage performance of the heat storage system at different periods. In this paper, based on three objective parameters: effective time of heat storage (teff), heat storage capacity (Q), and system entropy increase (Sgen) of the heat storage process, a multi-objective optimization design of heat storage system is carried out. In addition, to solve the heat dissipation problem of the lunar night, the natural lunar regolith insulation layer was added to evaluate the heat storage and insulation of the lunar night. The results show that different types of the heat storage system can be obtained by changing the structure parameters. The heat storage efficiency of the heat storage system with a large radius is still 0.59 after a long period of heat storage. The minimum thickness of the varied-temperature layer can be reduced to 60 % of the height of the whole system. Additionally, the insulation layer can effectively reduce energy loss at night, but the effect of improving thermal insulation performance is limited when the insulation layer thickness is too thick.

Opposites Attract: Electrostatically Driven Loading of Antimicrobial Peptides into Phytoglycogen Nanocarriers.

Antimicrobial peptides, such as GL13K, have a high binding selectivity toward bacterial membranes, while not affecting healthy mammalian cells at therapeutic concentrations. However, delivery of these peptides is challenging since they are susceptible to proteolytic hydrolysis and exhibit poor cellular uptake. A protective nanocarrier is thus proposed to overcome these obstacles. We investigate the potential to employ biodegradable phytoglycogen nanoparticles as carriers for GL13K using a simple loading protocol based on electrostatic association rather than chemical conjugation, eliminating the need for control of chemical cleavage for release of the peptide in situ. Both the native (quasi-neutral) and carboxymethylated (anionic) phytoglycogen were evaluated for their colloidal stability, loading capacity, and release characteristics. We show that the anionic nanophytoglycogen carries a greater cationic GL13K load and exhibits slower release kinetics than native nanophytoglycogen. Isotope exchange measurements demonstrate that the antimicrobial peptide is entrapped in the pores of the dendritic-like macromolecule, which should provide the necessary protection for delivery. Importantly, the nanoformulations are active against a Pseudomonas aeruginosa clinical isolate at concentrations comparable to those of the free peptide and representative, small molecule antibiotics. The colloidal nanocarrier preserves peptide stability and antimicrobial activity, even after long periods of storage (at least 8 months).

Multilayer-structured carbon fiber fabric/graphene oxide/Fe3O4/epoxy composite for highly efficient mechanical and electromagnetic interference shielding

Nowadays, it is quite difficult to develop a facile, efficient, and easy large-scale production method to obtain the composite that can maintain a balance of Electromagnetic interference (EMI) shielding properties and mechanical properties. Herein, this work adopted the technology of electrohydrodynamic atomization deposition (EHDAD), layer-by-layer (LbL) assembly and heat-pressing to prepare carbon fiber fabric/graphene oxide/Fe3O4/epoxy (CFf/GO/Fe3O4/epoxy) composite. The research results show that the CFf/GO/Fe3O4/epoxy composite can maintain a good balance between mechanical and EMI performance. More specifically, the tensile strength of CFf/GO/Fe3O4/epoxy-4 composite can reach 565.1 MPa, which is higher than that of other composites reported previously. This can be attributed to the synergistic effect of covalent bonds and van der Waals forces improved the mechanical properties of the composite. Benefitting from the unique multi-layer structure and the synergistic effect of nanoparticles, the EMI shielding performance of CFf/GO/Fe3O4/epoxy composite can reach a maximum of 32.9 dB. The improvement of the EMI properties of composite was mainly attributed to the dielectric loss and magnetic loss. Surprisingly, the composite has excellent mechanical stability and EMI shielding stability even after long periods of storage. It is believed that this work opens up more possibilities to provide EMI shielding materials with outstanding mechanical properties.

Effects of Ionic Liquids on the Stabilization Process of Gold Nanoparticles.

Improving the stability of the gold nanoparticles (AuNPs) is an important challenge in nanoscience, given that the activity and ubiquitous application of the AuNPs in different fields depend largely on their stability in the solution phase. Ionic liquids (ILs) can be used as new alternatives in comparison to water and organic solvents due to their considerable properties to elevate the stability and resistance of the AuNPs against aggregation for a long period of storage. In this study, we employ molecular dynamics simulation and quantum chemistry calculations to investigate the effects of amino acid ILs ([BMIM][Gly], [BMIM][Leu], [BMIM][Pro], [BMIM][Val], and [BMIM][Ala]) on the stability and aggregation process of the AuNPs from the molecular viewpoint. Our results suggest that ILs can prevent AuNP aggregation. These ILs penetrate the solvation shell of the nanoparticles and by increasing the electrostatic repulsions on the surface of the AuNPs improve their stability against aggregation. Moreover, the [BMIM]+ cation is more effective on the stability of the AuNPs in comparison with the corresponding anions. The ring of the cation, due to the stronger interaction with the AuNPs compared to the side chain, contributes predominantly to the stability of the nanostructures. Our quantum chemistry calculations confirm that dispersion interactions between the cation and anions of the ILs and the surface of gold play a key role in the stability of the IL-AuNP complexes. [Leu]- anion has the strongest dispersion interactions with the metal surface and forms the most stable complex with the AuNPs. Overall, the results of this study offer new insights into the properties of amino acid ILs as effective agents to improve the stability of AuNPs for long-term storage.

The Impact of Raw Milk Quality, particularly Thermoduric, and Storage Temperatures on the Keeping Quality of Pasteurized Milk

Abstract This study was aimed to investigate the effect of raw milk qualities on their corresponding pasteurized milk stored at different chilled temperatures. Raw milk collected from two different sources, Banhong (BH) milk farm and Mae Tha (MT) collection center, were pasteurized at 78 ± 2ºC for 30 s and kept for 21 days at 4-8ºC. During the storage period, representatives of milk treatments were assessed for their chemical, microbiological and sensorial characteristics. Collected data revealed that there was only minor alteration for the chemical properties of pasteurized milk throughout the studied storage period. The microorganism numbers in the pasteurized milk were significantly increased during storage and higher at higher storage temperatures. Poorer microbial quality of raw milk, including thermoduric bacteria, strongly contributed to higher microbial load of the correspondence pasteurized milk during chilled storage. The coliform number of all the pasteurized milk samples was found to be below 1 cfu/ml during 21 days of storage, while no Escherichia coli, Listeria monocytogenes and Staphylococcus aureus was detected in the pasteurized milk samples. The appraisal of the sensory features of pasteurized milk, including color, flavor, odor, creamy taste, texture and overall acceptance, were gradually decreased with longer storage period. Keywords: Pasteurized milk, Storage temperatures, Raw milk, Microbial quality, Chemical properties