Optimum Storage Temperature Research Articles

Characterization of Partially Purified and Immobilized Protease Extracted from Silver Catfish (Pangasius Sutchi) Viscera

Viscera is known as one of the richest sources of proteolytic enzymes. However, the biggest problem regarding enzyme is the rapid deterioration and lose in functional properties due to inefficient treatment and improper storage condition. Therefore, in this study, protease from silver catfish viscera have been extracted, partially purified by acetone precipitation method and immobilized in the calcium alginate beads. Concentrations of 2.99% (w/v) sodium alginate and 0.30 M calcium chloride were used to produce the immobilized protease. Then, the partially purified and immobilized protease were characterized in different range of pH, temperature and storage period in order to establish a greater protease stability during storage and increase in its efficiency. Proteolytic activity of the partially purified and immobilized protease in the alginate beads were measured by using casein as a substrate. The highest proteolytic activity for partially purified protease was recorded at pH 4 (5709.76 CDU/mg) and 40 °C (6061.14 CDU/mg) and for immobilized protease at pH 5 (3987.85 CDU/mg) and 50 °C (4956.54 CDU/mg). For storage stability, the partially purified protease has optimum storage temperature at – 40 °C while the immobilized protease at 4 °C. At optimum storageondition, the partially purified protease and immobilized protease have storage efficiency of 17.44 and 24.50%, respectively until 6th days of storage. Overall, the results showed that immobilization of protease improved enzyme limitation such as proteolytic activity, stability and the purity.

Cold or Not So Cold?-Static Organ Preservation at 10 °C May Prolong Organ Preservation and Facilitate Transplant Logistics.

Cold or Not So Cold?-Static Organ Preservation at 10 °C May Prolong Organ Preservation and Facilitate Transplant Logistics.

Stability of Amylase Crude Powder from Aspergillus awamori KT-11 at Different Storage Temperatures

Amylase is one kind of biotechnology product that has been used in many sector industries. Production of amylase powder from Aspergillus awamori KT-11 has been optimized successfully in the previous study. However, the stability of its activity, which is crucial in industrial application, has not yet been well studied. This study aimed to investigate the stability of amylase crude powder activity from A. awamori KT-11 at different storage temperatures. Amylase crude powder was stored at 4oC and 25oC. For the stability test, the crude powder with optimum storage temperature was diluted with phosphate buffer pH 4.8 and stored at 4oC, 25oC, and -20oC. The results showed that the activity of amylase crude powder was stable at 25 oC after nine months of storage with total activity of 2807 U/mL. On the other hand, the amylase extract liquid enzyme shows better activity when stored at 4 oC (with total activity 1000 U/mL after four-week storage time) than stored at temperatures 25oC or -20 oC. The findings also showed that crude amylase liquid extracts are not stored in a negative temperature environment. This is beneficial to enterprises because it lowers the cost of obtaining negative temperatures and saves energy.

Postharvest performance interpretation and storage temperature optimization in some newly introduced melon hybrids

Temperature is a key factor in melon cold storage. Thus, optimizing storage temperature is an important goal in postharvest research. In this experiment, postharvest attributes of four inbred lines and five derivative hybrids were investigated under three storage temperatures (1, 4, and 12°C). Melon fruit were evaluated for their main characteristics directly after harvest and postharvest changes were monitored through cold storage period. Cluster analysis results showed that most of the hybrids clustered with their maternal parents illustrating the significant role of cytoplasmic inheritance for the studied traits. Similarly, principal component analysis clustered the studied types into three clusters according to their average postharvest behaviour. The best postharvest performance belonged to inodorus and cantalupensis netted melon with their intercrossing breeds. While the dudaim inbred line and its hybrid scored the highest postharvest changes. Response surface analysis showed that 1.8°C was the optimum storage temperature for inodorus and cantalupensis clusters, while 5.1°C was the best storage temperature of dudaim cluster. The results of the current study are similar to previous reports for optimum storage temperature in similar melon types.

Comparison of Optimal Storage Temperature and Collection Reagents for Living Bacterial Cells in Swab Samples

Comparison of Optimal Storage Temperature and Collection Reagents for Living Bacterial Cells in Swab Samples

СТВОРЕННЯ БАНКУ СЕЛЕКЦІЙНОГО МАТЕРІАЛУ

Аn important issue of the selection process is the preservation of the source and obtained material, especially cross-pollinated crops, which significantly lose their viability by inbreeding. Creating a bank of genetic resources using biotechnological methods will effectively solve this problem. The aim of the work was to determine the conditions for the formation of a genetic bank of valuable winter rye materials with changes in temperature and modeling of the nutrient medium for long-term disposal of cloned plants and the use of active collection of original and created forms in the selection process. To deposit the clones, a nutrient medium, which included macro- and microelements according to the Murashige-Skuga medium was used. The nutrient substrate modified with cytokinins and carbohydrates. The clones in culture rooms at a temperature of 6–12 °С and low light intensity (2 kLk) were stored. In the course of research the conditions of creation of an active collection of plants of winter rye with use of temperature restriction and modification of a nutrient medium are defined. A consistent technological scheme for the conversion of plant material into a state of relative anabiosis has been developed. It is proved that the optimal storage temperature for samples is 6 °С. Survival of plants at the specified temperature regime after 12 months of deposition on average by genotypes at the level of 78,2 % was recorded. Modification of the nutrient medium with agar-agar at a concentration of 12,0 g/l increases the proportion of viable clones to 81,3 %, and the introduction into the substrate of an increased concentration of growth regulators, in particular 6-BAP (2,0 mg/l) and sucrose 40,0 g/l and a gradual decrease in temperature to 10 °С prolongs the period of deposition of cloned plants without changing the substrate and the shelf life of breeding material in isolated crops. Using of biotechnological methods for the preservation and reproduction of valuable material intensifies the selection process of obtaining initial samples of winter rye.

Effects of Storage Temperature on Postharvest Quality of Malaysian Grown Fig (Ficus carica L.) cv. Ipoh Blue Giant

Fresh fig (Ficus carica L.) is delicate and perishable with short postharvest life. Generally, refrigeration is often used to prolong fruits’ shelf life. However, fruits from the tropical region are temperature-sensitive with an adverse impact on quality if stored below their critical temperature. Thus, this study was carried out to determine optimal storage temperature for Malaysian grown figs cv. Ipoh Blue Giant. Varying temperatures (5, 10 and 15 °C) were used to observe the responses of the fruit quality during zero, three, six, nine, 12 and 15 storage days. Results showed that respiration and ethylene production rates, weight loss, pH, titratable acidity and antioxidant activities (as assayed using 1,1-diphenyl-2-picryl-hydrazyl and 2,2’-azino-bis[3-ethyl-benzothiazoline-6-sulfonic acid]) of fresh figs were affected significantly by the interaction between storage temperatures and days. Fresh figs stored at 5 °C showed the lowest respiration rate among three storage temperatures during nine and 12 days of storage. Fresh figs kept at 5 °C experienced the least firmness and water loss compared with the ones stored at 10 and 15 °C indicating that 5 °C was beneficial in retaining the eating quality and prolonging the postharvest life of the fruit.

The coupled effect of light and temperature on dormancy release and germination of Pinus koraiensis seeds

Elucidating the regulatory mechanisms of environmental factors on seed dormancy and germination will provide guidance for tree regeneration. Toward understanding the coupled effect of light and temperature on dormancy release and germination of Pinus koraiensis seeds, we set up three light conditions (L200: 200 μmol m−2 s−1, L20: 20 μmol m−2 s−1, L0: 0 μ m−2 s−1) and four storage temperatures [T-5: − 5 °C (50 days), T5: − 5 °C (50 days) + 5 °C (50 days), T25: − 5 °C(50 days) + 5 °C (50 days) + 25 °C (50 days), T15: − 5 °C (50 days) + 5 °C (50 days) + 25 °C (50 days) + 15 °C (50 days)] using imbibed seeds, then quantified phytohormones gibberellic acid (GA3) and abscisic acid (ABA) during the stratification. Germination percentage (GP), mean germination time (TM), and germination value (GV) under 25/15 °C temperature and the three light conditions were then determined. Phytohormone levels and germination performances were significantly affected by light and temperature. No consistent trend was found between the phytohormone levels and GP caused by light levels. Under the three light conditions, ABA concentrations in the embryo and endosperm decreased as storage temperature shifted from T-5 to T25 and increased from T25 to T15; GA3 decreased in nearly all four storage temperatures. GP reached 40–60% in T25 storage without light irradiance. In the three light conditions, GP and GV were higher at T5 and T25 than at T-5 and T15; so T5 and T25 are considered as optimum storage temperatures for dormancy release and germination. At optimum temperatures, light (L200, L20) significantly increased the GP and GV compared with the dark (L0). At L200 and L20, significant negative correlations between GV and the ABA concentrations and positive correlations between GV and GA/ABA in the seed embryo were found. Temperature played a more important role in primary dormancy release and germination; light was unnecessary for primary dormancy release. Light facilitated seed germination at optimum temperatures. The dormancy release and germination of P. koraiensis seeds were controlled by a decrease in ABA concentrations or an increase in GA/ABA induced by temperature variations.

Evaluation of postharvest storability of Ponkan mandarins stored at different temperatures

Abstract The effects of storage temperature on postharvest storability, quality attributes and antioxidant enzyme activities of harvested Ponkan mandarins were investigated. Fresh fruits were randomly divided into four groups and stored at different temperatures [5 ± 1 °C (S5), 10 ± 1 °C (S10), 15 ± 1 °C (S15), and 20 ± 1 °C (S20 or control)] for 120 days. The results indicated that, compared with the control fruit, low-temperature storage at 10 °C significantly delayed the increase in fruit decay rate, weight loss, citrus colour index, respiration intensity, relative electrical conductivity, the accumulation of hydrogen peroxide and malondialdehyde, retarded the decline in L* value, retained high contents of total soluble solid, titratable acid, vitamin C, total phenol and total flavonoid, as well as higher activities of antioxidant enzymes – superoxide dismutase, catalase, peroxidase and ascorbic peroxidase. The principal component analysis results showed that low-temperature storage significantly maintained the postharvest quality of Ponkan mandarins, with fruit stored at 10 °C having no significant difference from the fruit stored at 5 °C, but markedly higher than those fruit stored at 15 °C. The comprehensive result of single-factor analysis and PCA showed that 10 °C could be used as the optimum storage temperature for improving the postharvest storability of Ponkan mandarins.

Utility of carboxylated poly L-lysine for the liquid storage of bottlenose dolphin semen

Assisted reproduction techniques are required to maintain a genetically diverse captive population of bottlenose dolphins. These techniques include semen preservation, and liquid storage has been proposed as a suitable alternative to cryopreservation, but the optimum conditions, in terms of temperature, duration, and media, have yet to be fully established. The aim of this study, therefore, was to determine the optimum temperature for the liquid storage of dolphin semen during a 14-day period and the usefulness of carboxylated poly-L-lysine (CPLL) as an additive to the semen extender used for the liquid storage. The semen was collected from a mature male dolphin housed at the Kagoshima Aquarium, Japan, transferred into a Beltsville (BF5F) extender, and analyzed for motility and characteristics after five-fold dilution. The optimum temperature was determined by evaluating sperm viability after liquid storage at 4, 17, or 36 °C, and the usefulness of CPLL was evaluated at concentrations of 0%, 0.5%, 1.0%, 2.0%, and 3.0% (v/v) at the optimum temperature. Sperm stored at 4 ℃ had a greater motility maintenance compared with samples stored at 17 or 36 ℃. The most efficacious storage regimen at various time points occurred when there was addition of CPLL at 1.0% (v/v) in terms of sperm motility and other relevant determinations, with this storage approach having greater efficacy that samples stored without CPLL. The most efficacious processes for preserving bottlenose dolphin sperm functions is storage at 4 °C and with there being semen extender supplementation of 1% CPLL.

Structural responses of energy storage pile foundations under thermal-mechanical loadings

Recently studies have investigated feasibilities to configure pile foundations as energy storage media using a small-scale compressed air energy storage technology. These studies consider that storage temperatures of compressed air can be lowered entirely down to ambient temperatures through a cooling process. This assumption may not be feasible and economical due to the efficiency of the cooling process. As an alternative option, a higher storage temperature can be allowed by reducing the cooling time, which can cause additional thermal-mechanical loadings to the pile foundation. This paper investigates structural responses of reinforced concrete pile foundations subjected to combined structural, compressed air pressure, and thermal-mechanical loadings through nonlinear dynamic heat transfer and thermal-mechanical analyses. Several parameters were studied, including pile spacing, pile inner diameters, and concrete grades. Analysis results show that thermal-mechanical loading can reduce critical tensile stresses and change stress distributions in the pile section originated from compressed air pressure. Design recommendations were made to determine an optimal storage temperature and an allowable loading cycle for the energy storage pile foundation.

Can Edible Coatings Maintain Sweet Pepper Quality after Prolonged Storage at Sub-Optimal Temperatures?

This work evaluated the efficacies of different coatings: chitosan, gelatin and chitosan-gelatin applied layer-by-layer (LbL); for maintaining the quality of sweet peppers that were stored for 3 weeks at a sub-optimal temperature (1.5 °C) and at an optimal storage temperature (7 °C). After the cold-storage period, fruits were kept under marketing conditions (21 °C) for 3 more days. An edible chitosan coating (2%) effectively alleviated chilling injury and the incidence of decay, and also preserved the nutritional quality of sweet peppers that were kept for 3 weeks at 1.5 °C plus 3 more days at 21 °C. The chitosan coating was more effective than the two other coatings. All three coating treatments significantly reduced external CO2 production, as compared to uncoated control fruit. Storage temperatures did not significantly affect external CO2 production, although CO2 production was slightly higher at 1.5 °C. The chitosan coating exhibited good CO2 gas permeability properties and the peppers coated with that material had lower respiration rates than those in the other two experimental treatments or the control. From a practical point of view, chitosan coating could replace the plastic bags previously found to alleviate chilling injury in peppers that are stored at 1.5 °C as a quarantine treatment.

A general procedure for predicting the remaining shelf life of nectarines and peaches for virtualization of the value chain

Decision-making along the supply chain requires accurate estimates of the remaining shelf life (RSHL) depending upon not only the initial storage conditions and duration but also aspects such as the variety or condition of the fruit at harvest. Offering ready-to-eat fruit on at the retail level, is a frequent marketing strategy in which management of shelf life is mandatory. The most widespread models, so-called generic shelf life models for estimating the RSHL gather the actual temperature series and the optimal storage temperature while assuming standard values for other parameters such Q10 or the reference shelf life. In this work, a general mathematical procedure, and corresponding algorithm are proposed to adjust the parameters of the generic RSHL model referring to several varieties of peaches and nectarines. Postharvest protocols are simulated to obtain ready-to-eat fruit for recently bred varieties. To this aim, temperature was recorded continuously throughout the postharvest protocol, while instrumental and sensory evaluations were taken at the end of each stage of the protocol. Outputs of a principal component analysis based on instrumental data allowed to i) identify the instrumental variables most relevant to sensory evaluation and corresponding evolution under shelf life conditions and ii) define a multidimensional estimator of shelf life. The particular values of this multidimensional estimator together with the temperature series are the basis to solve the equation that lead to specific values of Q10 and reference shelf life for each variety in the study. The average reference shelf life of peaches is bounded to 24 d, 30 % shorter (10 d less) than the average shelf life of nectarines. The Q10 values are bounded between 1.5 and 2.8, highlighting the varietal effects. Generally, Q10 values for peaches are indicative of a higher susceptibility to the breakage of the cold chain compared to nectarines.

Development of a process for large scale production of PfRH5 in E. coli expression system

The Plasmodium falciparum reticulocyte binding protein homologue 5 (PfRH5) has recently shown great promise to be developed as a vaccine candidate to prevent blood-stage malaria. However, because of its molecular complexity, most previous efforts were focused on expressing PfRH5 in its native and soluble form. Here, we describe the E. coli expression of full-length PfRH5 as inclusion bodies (IBs), followed by its high cell density fermentation at 1, 5 and 30 L scale. Denatured full-length PfRH5 was purified using a two-step chromatography process before being refolded using design of experiments (DoE). Refolded PfRH5 was further purified using size exclusion chromatography (SEC), recovering high purity antigen with an overall yield of 102 mg/L from fermentation cell harvest. Purified PfRH5 was further characterized using orthogonal analytical methods, and a short-term stability study revealed −80 °C as an optimum storage temperature. Moreover, refolded, and purified PfRH5, when formulated with adjuvant Glucopyranosyl A lipid stable emulsion (GLA-SE), elicited high antibody titers in BALB/c mice, proving its potential to neutralize the blood-stage malarial parasite. Here, we establish an E. coli-based process platform for the large-scale cGMP production of full-length PfRH5, enabling global malaria vaccine development efforts.

Fingerprinting diverse nanoporous materials for optimal hydrogen storage conditions using meta-learning.

Adsorptive hydrogen storage is a desirable technology for fuel cell vehicles, and efficiently identifying the optimal storage temperature requires modeling hydrogen loading as a continuous function of pressure and temperature. Using data obtained from high-throughput Monte Carlo simulations for zeolites, metal-organic frameworks, and hyper-cross-linked polymers, we develop a meta-learning model that jointly predicts the adsorption loading for multiple materials over wide ranges of pressure and temperature. Meta-learning gives higher accuracy and improved generalization compared to fitting a model separately to each material and allows us to identify the optimal hydrogen storage temperature with the highest working capacity for a given pressure difference. Materials with high optimal temperatures are found in close proximity in the fingerprint space and exhibit high isosteric heats of adsorption. Our method and results provide new guidelines toward the design of hydrogen storage materials and a new route to incorporate machine learning into high-throughput materials discovery.

Investigation of the optimum conditions for adsorptive hydrogen storage

Cryogenic adsorption using microporous materials is one of the emerging technologies for hydrogen storage in fuel cell vehicles. Metal–organic frameworks have been identified as suitable adsorbents exhibiting large hydrogen sorption at 77 K. With respect to technical realization, in this work, the deliverable capacity at the optimal storage temperature was determined for a series of MOFs in comparison to zeolite Ca-A. The deliverable capacity is defined as the amount of hydrogen released between a maximum tank pressure and a minimum back pressure and shows a maximum which defines the optimum operating temperature. This optimum operating temperature depends on the pore size of the adsorbent and the chemical properties of the surface. A number of materials are identified that exhibit optimal operating temperatures well above 100 K. A higher optimal storage temperature, however, typically results in a lower deliverable capacity.

Effect of storage temperature on the quality of kepok banana (Musa paradisiaca formatypica)

Kepok bananas are processed bananas that have ABB genotype, the letter B indicates that banana kepok has a stronger resistance to disease and chilling injury in cold temperatures storage. Storage at cold temperatures can extend the shelf life of bananas, because cold temperatures can slow down the respiration and enzymatic processes. The purpose of this study is to observe the effect of storage temperature on quality and shelf life, and to determine optimum storage temperature. The method used is storage temperature at room, 15oC and 10oC until the banana is damaged. The parameters observed were respiration patterns, weight loss, hardness, fruit skin color, total acid, vitamin C, pH, and total soluble solids. The results showed that bananas stored at cold temperatures (10oC and 15oC) can last up to 20 days while at room temperature only lasts for 10 days. Kepok bananas stored at 10oC have not shown symptoms of chilling injury.

Effect of temperature and relative humidity on the viability and longevity of eastern bracken (Pteridium aquilinum var. latiusculum) spores for long-term storage

Desiccation conditions and storage temperature are crucial factors for the successful long-term storage of fern spores. This study aimed to determine the optimal desiccation conditions and storage temperatures for the long-term survival of eastern bracken (Pteridium aquilinum var. latiusculum) spores. The effect of different storage temperatures (25°C, 4°C, −20°C, −80°C, and −196°C for up to 48 weeks) on spore germination and sporophyte development was investigated in collected spores. The germination percentage remained constant in all spores, except in those stored at −20°C and 25°C. Spores stored at −20°C had the lowest germination percentage and were almost completely nonviable. The collected spores were desiccated for one week at various relative humidity (RH) levels equilibrated using saturated salt solutions. The water content was measured in desiccated spores, and the spores were stored in liquid nitrogen for up to 48 weeks. The water content of the spores desiccated at 15–55% RH was 5.0–5.4%, and their germination percentage remained constant with storage time. Desiccation at 94% RH increased the spore water content to 9.5% and decreased the germination percentage. The relatively high water content in spores was not suitable for their long-term storage. Long-term survival of the spores can be achieved by desiccating the spores at low RH to adjust the spore water content to 5% prior to their storage at low temperature.

Determining the optimal storage time and temperature for performing platelet function assays and global hemostasis assays

Platelet function assays and global haemostasis assays are essential in diagnosing bleeding tendencies, with light transmission aggregometry (LTA) as golden standard. The Multiple Electrode Aggregation (Multiplate), platelet function assay (PFA) and rotational thromboelastometry (ROTEM) are mostly used as whole-blood screening tests. Currently, patients have to travel to specialized laboratories to undergo these tests, since specific expertise is required. Pre-analytical variables, like storage time and temperature during transport, are still considered to be the most vulnerable part of the process and may lead to discrepancies in the test results. We aim to give a first impression on the stability of blood samples from healthy volunteers during storage and investigate the effect of storage time (1, 3, 6 and 24 hours) and temperature (4°C, room temperature and 37°C) on the Multiplate, PFA, ROTEM and LTA test results. Our data indicated that, for the PFA, whole blood can be stored for 3 hours at room temperature. Whole blood used for the Multiplate and ROTEM can be stored for 6 hours of storage. For LTA, PRP and whole blood were stable up to 3 hours at 4°C or room temperature and 6 hours at room temperature, respectively.

Broad host range bacteriophages found in rhizosphere soil of a healthy tomato plant in Bulgaria

The urgent need of research of new approaches to control bacterial disease on economical important crops, focuses our attention on bacteriophages as alternative biocontrol agents. Thus, the purpose of this paper is to present the isolation and initial characterization of three bacteriophages (SfXv124t/1, 2 and 3) isolated from rhizosphere soil of a healthy tomato plant in Bulgaria that are capable to lyse three phytopathogenic bacteria. The initial characterization includes determination of: their host range, plaque morphology, optimal storage temperature of pure phage lysates, their sensitivity to UV light, thermal inactivation, optimal multiplicity of infection (MOI) and virion morphology. The obtained results showed that one of the phage isolates was capable to lyse wild strains from three phytopathogenic bacterial species: Xanthomonas vesicatoria, Xanthomonas euvesicatoria and Xanthomonas gardneri, and the two remaining phages were active against X. vesicatoria and X. euvesicatoria. On X. vesicatoria lawn, the phages produced the same plaque types that differed only in their size. Storage at 4 °C for 26 days did not lead to decrease in phage titer as opposed to storage at 28 °C followed by decrease to varying degree for all three phages. The results obtained after exposure of the phage lysates to sunlight (UVA + B) and UVC light in separate experiments showed that UVC had a potent phagocidal effect as after 50 min of exposure there were no viable phages in the samples. UVA an UVB had lethal effect for two of the phage isolates and absolutely no lethal effect for the third one as after 50 min of exposure to sunlight there was no decrease in the initial phage titer. Phage isolates were tested for their thermal inactivation after incubation of pure phage lysates at three different temperatures: 55 °C, 75 °C and 95 °C for a period of 10 and 30 min. The most lethal temperature turned out to be 95 °C as after 10 min there were no viable phages in the samples. Phage isolate SfXv124t/1 was the most susceptible as its titer decreased by 1 lg after 10 min of incubation at 55 °C and by another 1 lg after 30 min. The most thermally resistant isolate was SfXv124t/3 as its titer remained stable after 30 min of incubation at 55 °C and decreased only by lg after incubation at 75 °C for 10 min. The optimal MOI for SfXv124t/3 was 0,01 (tested range 0,01–100) with maximal phage titer, reported at the 24th hour of incubation. TEM micrographs of the same isolates reveals that it belongs to family Podoviridae.