Shelf Lifetime Research Articles

Relationship of season with milk characteristics, yield, and shelf life of cheese in a hot climate

E Objective: the objective of the study was to identify whether there is a relationship between the environmental conditions of high temperature and humidity with the parameters of cheese yield and shelf life of Oaxaca-type cheese, made throughout two different times of the year, delimited by environmental temperature, in the Mexicali Valley, Baja California, Mexico. Design/ Methodology/ Approach: from January to November, ambient temperature and relative humidity, characteristics of the milk used at the time of reception (temperature, acidity, density, somatic cell count and microorganism count), yield, and shelf life of the cheese were recorded. These variables were related to season (summer and winter) and to different Temperature and Humidity Index– THI intervals. An analysis of variance was performed, also, the relationship among sets of variables by Pearson correlation, and the multiple mean difference with the Tukey test (p ≤ 0.05). Results: significant differences were observed in the density, acidity, temperature, somatic cell count and cheese yield of milk due to the effect of the time of year. In addition, an 11% decrease in cheese yield was found as the maximum THI exceeded 77 units. The shelf life showed positive significant difference (p ≤ 0.05) when milk was pasteurized, but it was not affected by the THI. Limitations/ Implications of the study: this study was limited to a single period of analysis; so, it is necessary to monitor, and include additional milk quality variables. Conclusions: heat environmental conditions negatively impact the characteristics of the milk, therefore reducing the yield of Oaxaca-type cheese. The microbiological characteristics are unfavorable during the hot season; the pasteurization of milk is the main factor that increases the shelf life of the cheese.

PEDOT:PSS-Free Quantum-Dot Light-Emitting Diode with Enhanced Efficiency and Stability.

Although high-performance quantum-dot light-emitting diodes (QLEDs) have been achieved, their stability is still limited due to the use of unstable PEDOT:PSS as the hole injection layer (HIL). Here, we developed a PEDOT:PSS-free QLED by using a binary PTAA:F4-TCNQ HIL. Because the PTAA, with a highest occupied molecular orbital (HOMO) level of ∼5.20 eV, can facilitate hole injection from ITO to the hole transport layer, and the F4-TCNQ can act as the electron acceptor dopant to improve the hole density and hole mobility of PTAA, the PTAA:F4-TCNQ HIL can exhibit excellent hole injection capability. As a result, the PEDOT:PSS-free QLED can exhibit a high EQE of 24.19% and an impressive brightness of 367,200 cd/m2, which are significantly higher than those of conventional QLEDs. Moreover, due to the improvement of device performance and the removal of PEDOT:PSS, the PEDOT:PSS-free QLED can also exhibit a high T95 operational lifetime of 4206 h at 1000 cd/m2 and an excellent T80 shelf lifetime of 207.41 h at 136400 cd/m2, which are about 1.6- and 3.3-fold those of conventional QLEDs, respectively. We believe that the demonstrated PEDOT:PSS-free QLED, with higher performance and stability, will promote the practical application of QLEDs in displays.

Development of bio-active cotton fabric coated with betalain extract as encapsulating agent for active packaging textiles

The development of bio-active cotton fabric based on natural polymers and pigments has been a significant material for biodegradable textile packaging in recent years. Betalain extracted (BE) from Red beet root (RBR) is a rich source of natural pigments and has potential health benefits as an antioxidant and in biological activities which used as food, beverage, and drug colorant. However, BE pigments are photochromically unstable and have interest applications, thereby motivating the use of microencapsulation technology to maintain their stability and increase their shelf lifetime. Thus, in the present work Incorporating BE into gelatinized corn starch (GS) and Arabic gum (AG) for manufacturing stabilized BE microcapsules with tunable antioxidant and biological properties by freeze-drying method. The produced encapsulating agent (EA) powders were analyzed by scanning electron microscope (SEM) for particle morphology and FTIR of selected EA was carried out. Monitoring of coloring strength values (K/S) and Color parameters before and after storage as well as storage stability of these microcapsules at different pH’s was also studied. The current study was performed to design multifunctional cotton fabric, for this purpose the cotton fabric was treated with keratin to improve its affinity toward 100 % BE, with and without (BE) EA were determined using a pad dry process. The chemical properties, physical properties, mechanical properties, thermal stability, and functional properties of the coated fabrics with and without (BE) as well as color parameters were determined. The results showed that the fabric coated with 100 % BE and 30 % BE incorporating or encapsulating with 60 % GS and 10 % AG exhibited good mechanical properties, excellent thermal stability, and significant antioxidant and antimicrobial activity compared to the uncoated fabric. The antioxidant release of BTE from the fabric coated with 60/10/30 EA was controlled by diffusion. According to the results, the developed multifunctional coated fabrics with BE encapsulating agent can be considered as a good potential material for active packaging textiles for various applications.

Temperature endurable face-sealing polyisobutylene film with contactable liquid desiccant for the encapsulation of OLEDs

We propose a face-sealed encapsulation solution with simple process and low cost. The polyisobutylene encapsulation patch mixed with calcium oxide particles is attached to the surface of the OLEDs that is exposed to the hygroscopic agent in a face-sealing manner. We find that this encapsulation scheme exhibited excellent waterproof performance. The encapsulated OLED has a long shelf lifetime in water under high temperature conditions, which is manifested in a long underwater shelf lifetime of T95 (luminance drops to 95 % of the initial luminance) of over 336 h at 60°C. We believe that this encapsulating technology can be applied to other organic optoelectronic devices, and the face-sealed encapsulating patch is flexible. This strategy can be extended to roll-to-roll processes to expand the application of flexible organic optoelectronic devices underwater.

Improving the air stability of flexible top-emitting organic light-emitting diodes

Flexible organic light-emitting diodes (OLEDs) are promising light sources for biomedical applications. However, the use of these flexible devices has been restricted by their short shelf lifetimes due to poor ambient stability. Here, the fabrication of a long-lived flexible OLED is reported by replacing air-sensitive metals such as aluminum, and alkali metals used as n dopants, with silver. In addition, to achieve stable and efficient flexible OLEDs we tuned the optical cavity length to the second-order interference maximum. The device design has simple encapsulation and leads to an improvement in the air stability of flexible OLEDs which show a shelf lifetime of greater than 130 days whereas the conventional structure exhibits degradation after only 12 days. The proposed design for making flexible OLEDs demonstrates a great potential for using the devices for wearable bioelectronic applications.

Novel disposable screen-printed sensors based on copper oxide nanoparticles for sensitive voltammetric assay of antazoline

The fabrication and electroanalytical validation of a novel homemade screen-printed carbon electrode enriched with copper oxide nanoparticles (CuONPs/SPCEs) were demonstrated for sensitive and selective voltammetric determination antazoline (ANT) in eye drop solution and spiked serum samples. With a reported electrocatalytic activity, CuONPs catalyzed the oxidation of ANT at the electrode surface showing an irreversible anodic oxidation peak at 0.9 V under a diffusion-controlled electrode reaction. Based on the electroanalytical and molecular orbital calculation studies, oxidation of ANT molecule undergoes via oxidation of the aliphatic nitrogen atom within the ANT moiety. Linear calibration curves were illustrated covering the ANT concentration ranged from 0.01 to 3.819 µg mL−1 with and limit of detection 3 ng mL−1. The fabricated sensors enriched with CuONPs exhibited high fabrication and measurement reproducibility with a prolonged shelf lifetime (6 months). The electroanalytical approach presented adequate sensitivity and selectivity with a short analysis time, applying low-cost instrumentation and simple pretreatment protocol avoiding handling hazardous organic solvents. Trace ANT was monitored in the presence of different interfering species, degradation products, and xylometazoline hydrochloride (ZYL) in the co-formulated ophthalmic pharmaceutical samples. The CuONPs based voltammetric sensors were introduced as a reliable eco-friendly analytical tool for monitoring ANT in ophthalmic solutions and biological fluids with acceptable recovery values.

Novel Deliberately Sensitive and Selective Tetrahydrozoline Voltammetric Sensors Integrated with a Copper Oxide Nanoparticle/Zeolite Platform.

The present study introduced a novel disposable screen-printed carbon electrodes (SPCEs) modified with copper oxide/zeolite nanostructures for eco-friendly selective differential pulse voltammetric quantification of tetrahydrozoline (THZ) in eyedrop samples and biological fluids. Modification of the electrode matrix with copper oxide nanoparticles/zeolite nanostructures (CuONPs/ZY) with their effective and synergistic electrocatalytic activity enhanced the electrode performance against electrooxidation of THZ at 0.960 V in BR at pH 9.0 with a diffusion-controlled reaction mechanism. The tentative oxidation mechanism based on molecular orbital calculations postulates the oxidation of THZ molecules through oxidation of a nitrogen atom five-membered ring and the participation of two electrons/protons in the electrode reaction. Linear calibration curves were illustrated within a wide THZ concentration range from 0.24 to 57.2 μg mL-1 recording a limit of detection (LOD) value of 0.0799 μg mL-1. The CuONPs/ZY/SPEs exhibited improved performance compared with the sole reported THZ sensor-based gold film-plated carbon paste electrodes, in addition to their high reproducibility of fabrication and measurement and prolonged shelf lifetime. Tetrahydrozoline was successfully assayed in the presence of excipients, degradation products, and chloramphenicol. The presented voltammetric sensor can be considered as an eco-friendly and reliable analytical approach for monitoring THZ residues in eye drop samples and biological fluids with high recovery compared with the official pharmacopeial analytical protocol. The presented sensors were assessed according to an EcoScale tool and also compared with the reported THZ sensor.

Confronting positions: para- vs. meta-functionalization in triindole for p-type air-stable OTFTs

The 5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole core, namely triindole, is well-known for its prominent hole-transporting properties and air stability. The functionalization of this core is also rather versatile, which allows the modulation of its properties by anchoring targeted scaffolds to different positions, e.g. 3,8,13 (para with respect to the nitrogens), 2,7,12 (analogously meta) or the nitrogen heteroatoms. Therefore, triindole excels as a pivotal semiconductor to be exploited in long-lasting organic thin-film transistors (OTFTs). This report aims to shed light on the effect of functionalizing whether para or meta positions with sulfurated moieties, in the pursuit of an enhanced performance in OTFTs. Remarkably, meta-substituted derivatives outshone their para- counterparts in terms of thermal, optical, intermolecular arrangement and semiconductor properties, claiming mobility values up to 2 × 10−3 cm2 V−1 s−1 and a shelf lifetime beyond the analyzed period of 5 months. Analysis of the thin films by grazing incidence X-ray diffraction (GIRXD) and atomic force microscopy (AFM) revealed that the meta-substitution also induces a higher degree of order and better morphology, further corroborating the potential of this structural approach.

PbS Quantum Dots Ink with Months-Long Shelf-Lifetime Enabling Scalable and Efficient Short-Wavelength Infrared Photodetectors.

The phase-transfer ligand exchange of PbS quantum dots (QDs) has substantially simplified device fabrication giving hope for future industrial exploitation. However, this technique when applied to QDs of large size (>4nm) gives rise to inks with poor colloidal stability, thus hindering the development of QDs photodetectors in short-wavelength infrared range. Here, it is demonstrated that methylammonium lead iodide ligands can provide sufficient passivation of PbS QDs of size up to 6.7nm, enabling inks with a minimum of ten-week shelf-life time, as proven by optical absorption and solution-small angle X-ray scattering. Furthermore, the maximum linear electron mobility of 4.7×10-2cm2V-1s-1 is measured in field-effect transistors fabricated with fresh inks, while transistors fabricated with the same solution after ten-week storage retain 74% of the average starting electron mobility, demonstrating the outstanding quality both of the fresh and aged inks. Finally, photodetectors fabricated via blade-coating exhibit 76% external quantum efficiency at 1300nm and 1.8×1012Jones specific detectivity, values comparable with devices fabricated using ink with lower stability and wasteful methods such as spin-coating.

Stability-indicating UPLC assay coupled with mass spectrometry for the analysis of vilanterol degradation products in human urine

Vilanterol is a once-daily dose inhaler prescribed for asthma and chronic obstructive pulmonary disease. This study involved an investigation of vilanterol stability under acidic, basic, oxidative, thermal, and photolytic stress conditions. UPLC method was developed and validated for the analysis of vilanterol with its degradants. The drug was stable under photolytic and thermal stress conditions and degraded under acidic, basic, and oxidative stress conditions. Degradation kinetics was performed for acidic, basic and oxidative stress conditions. Kinetics parameters, K, half-life time (t1/2) and shelf-life time (t90) were assessed, and the degradation followed first order reaction. The method was linear from 0.10 to 100.00 µg mL−1 with accuracy, inter-day and intra-day precision from 99.45 to 100.02%, 0.391–0.694 and 0.041–0.345, respectively. Mass spectrometry was employed to elucidate the structure of the degradants, and the results revealed that certain degradation products were comparable to vilanterol metabolites. The World Anti-Doping Agency has prohibited the presence of vilanterol and its metabolites in athletes’ urine except for exercise bronchoconstriction with limited dose. So, quantification of vilanterol in the presence of its degradants was performed in human urine. The results revealed that the method was linear in range of 1.00 to 100.00 µg mL−1. Samples collection and experimental protocol was performed according to the guidelines of the Research Ethics Committee of the Faculty of Pharmacy, the British University in Egypt with approval No. CH-2305.

Effect of chitosan/plant oils edible coatings on minimally processed peach quality during storage

The edible coatings are capable to extend the shelf-life of minimally processed fruits and reduce the synthetic packaging’s waste. The used coating materials are obtained from renewable plant sources and byproducts of the food production. In addition, they are functional active ingredients. In this study, low-molecular weight fungal chitosan-based coatings with plant oil emulsions were used for coating of sliced peach. For characterization of the differently coated fruit pieces physical, physicochemical, microbiological and sensorial properties were examined during refrigeration. The used coatings extended the shelf-life time up to 10 days and the coated fruits had acceptable sensory parameters even at the end of the storage.

Factors Limiting Shelf Life of a Tomato-Oil Homogenate (Salmorejo) Pasteurised via Conventional and Radiofrequency Continuous Heating and Packed in Polyethylene Bottles.

Salmorejo is a tomato-oil cold puree commercialized as a "fresh-like" product requiring mild pasteurisation and chill storage to reach a suitable shelf lifetime. The objective of this study was to study the factors which limit the shelf life of salmorejo pasteurised via conventional or radiofrequency continuous heating, packed in high-density polyethylene bottles, and kept at refrigeration. The pasteurised-chilled salmorejo reached a long shelf life (4 months) compared to that of pasteurised tomato juices or purees. Mesophilic and pathogenic bacteria were easily inhibited in this acidic product. Salmorejo mainly showed oxidative and subsequent sensory changes. Initial enzyme oxidation was associated with some adverse effects (loss of vitamin C and lipid oxidation) at the first month, although there were no sensory implications. Salmorejo remained stable at the physicochemical and sensory levels for the following 3 months, though colour and viscosity changes could be measured with instruments. Between the fourth and fifth month, salmorejo showed clear signs of deterioration, including changes in appearance (slight browning and loss of smooth surface), odour/flavour (loss of freshness and homogenisation), and consistency (thinning trend). The shelf life of salmorejo is limited by long-term oxidative deterioration and their sensory implications.

Insights into the volatile flavor and quality profiles of loquat (Eriobotrya japonica Lindl.) during shelf-life via HS-GC-IMS, E-nose, and E-tongue

Loquat fruits are among the most popular Chinese fruits because of their unique taste and aroma. The quality profiles of these fruits during 18 days of shelf-life at 20 °C were elucidated by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), E-nose, and E-tongue. During shelf-life period, the properties and variations of 43 (20 aldehydes, 7 esters, 6 ketones, 1 alcohol, and 1 furan) volatile flavored compounds were determined by GC-IMS, which showed that the contents of methyl 3-methyl butanoate, ethyl acetate, and dimethyl ketone gradually decrease with prolonged shelf-life time, while (E)-2-heptenal, heptanal, (E)-2-pentenal, 1-penten-3-one 3-pentanone and 2-pentylfuran increase. The PCA based on the signal intensity of GC-IMS and E-nose, revealed that loquat fruits are well distinguished at different shelf-life times. The taste profile alternates as the storage time increases, along with higher pH, and lower amounts of total soluble solids, vitamin C, and total phenolics. The visual plots of GC-IMS, E-nose, and E-tongue had good consistency, and they characterized the aroma characteristics of loquat fruits well during different shelf-life periods. The findings of this research provide a useful understanding of the flavors of loquat fruits during their prolonged shelf-life, and a potential research basis for advancements in the loquat industry.

Impact of Bird Cherry (Prunus padus) Extracts on the Oxidative Stability of a Model O/W Linoleic Acid Emulsion

The delivery and uptake of adequate doses of a number of active compounds, including selected saturated and unsaturated fatty acids (frequently in the form of emulsion systems), is crucial to maintaining a healthy diet. The susceptibility of acids to oxidation and the time stability of emulsions are factors limiting their shelf life and storage time. Those parameters could be improved using selected additives, including antioxidants. In this study, we examined the influence of different bird cherry extracts (varying in the content amounts of bioactive compounds) on the oxidative stability of a model O/W linoleic acid emulsion, using C11-BODIPY581/591 as a fluorescent indicator. We also examined the effect of these extracts on the physicochemical properties of the emulsions and the time stability of the produced emulsion using the dynamic laser scattering technique. The antioxidative efficacy of extracts differed significantly, depending on the extraction method and conditions. The observed differences in the results could be attributed to variations in the specific compositions of the extracts used, which were more or less rich in terms of antioxidants or their synergistic effects. Our results indicated that acetone extract was the most effective with regard to both the oxidation stability and time degradation tests of the emulsions produced. Moreover, the addition of gallic acid did not always have a positive effect on the abovementioned properties.

Firmness prediction of 'Rocha' pear based on non-destructive methods and shelf-life using PLS-regression modeling

Knowledge of fruit firmness in the distribution chain is essential for stakeholders, including producers, agri-food industries, and consumers. In recent years, there has been a general interest in predicting ripening-related firmness with non-destructive techniques. The objective of this study was to create a model, based on non-destructive methods that assess directly critical physiological parameters and quality attributes related to ripening, along with shelf-life time, to predict firmness of 'Rocha' pear (Pyrus communis L.), a protected designation of origin (PDO) commodity. Hereto, pear firmness profile was assessed for ten days at room temperature, after removal from different storage periods at cold conditions. Ripening was evaluated based on color alterations, ethylene production, and respiration rate. Pear firmness decreased drastically over time, concomitant with the yellowing of the fruit skin and increased ethylene production and respiration rate. These characteristics and shelf-life time were correlated with firmness by applying the Partial Least Squares (PLS) procedure to develop a mathematical model for predicting pear firmness during ripening. The model explained 89 % of the firmness variance during ripening and, after validation, showed high accuracy (R2 = 0.87). To the best of our knowledge, this is the first time that these physiological parameters, directly related to ripening-firmness, have been used to predict pear firmness using non-destructive measurements of the samples.

A mixed-integer linear programming model for sustainable blood supply chain problems with shelf-life time and multiple blood types

The blood supply chain (BSC) is a complex system with optimization challenges, whose activities impact carbon emissions and the environment, especially with regard to the disposal of expired blood bag waste. This study proposes a new mixed-integer linear programming (MILP) model that considers multiple echelons, multiple blood types, transportation and production emissions, and blood bag shelf life to maximize profit in the blood supply chain system. The model is applied to a real-world case study. The research results confirmed that the model could mitigate the BSC challenges. We also conducted sensitivity analysis of patient demand parameters, blood production capacity, selling price, and shelf life to investigate the impact of the key factors affecting the total profit, costs, carbon emissions, and number of obsolete products.

Characteristics of Margarine Produced from Palm Stearin and Tilapia (Oreochromis niloticus) Oil with Carrageenan as Emulsifier

One of the tilapia waste produced is offal. The content contained in the innards of tilapia contains a lot of fat which can be used as raw material for making fish oil. Fish oil plays an important role in health because it contains a source of omega 3. The application of fish oil into margarine can be used in the manufacture of bakery products. Making margarine requires an emulsion stability, which functions so that oil and water can mix. One of the emulsion stability that can be used is carrageenan. The purpose of this study was to determine the effect of using carrageenan on the stability of the emulsion on the physical properties of margarine and to determine the best concentration. This study used a completely randomized design (CRD), using one factor, namely the carrageenan concentration of 0.1; 0.2 and 0.3. The test parameters observed were water content test, spreadability test, texture test, melting point slip test, emulsion stability and hedonic test. The result shows that carrageenan plays a significant role as an emulsifier agent for the tilapia oil based margarine as it enhances the physical chracteristics of margarine. The best test results at a concentration of 0.3% with a water content value of 14.64%. The results for the basting power were 3.93%, while the slip melting point test was 33.80ᵒC, the stability test results were 93.07%, the hedonic test was 7.37 < µ < 7.76. The research suggests that there should be further analysis of margarine shelf-life time and fatty acid composition.

Metal Oxide Interlayers Enable Lower-Cost Electrodes in PbS QD Solar Cells

PbS quantum dots (QDs) are an emerging light-absorbing material for thin-film solar cells. However, state-of-the-art solar cell architectures rely on a gold electrode, which raises material costs to 3× more than the 2030 US DOE SunShot target module price. Here, we enable both aluminum and copper electrodes to replace gold through a NiOx interlayer. An additional indium tin oxide (ITO) buffer layer between the NiOx interlayer and electrode further enables longer shelf lifetimes. By combining these layers, we lower electrode material costs in PbS QD solar cells by a factor of 130000 without compromising power conversion efficiency or stability.

Classification of early mechanical damage over time in pears based on hyperspectral imaging and transfer learning.

Mechanical damage of fresh fruit caused by compression and collision during harvesting and transportation is an urgent problem in the agricultural industry. The purpose of this work was to detect early mechanical damage of pears using hyperspectral imaging technology and advanced modeling techniques of transfer learning and convolutional neural networks. The visible/near-infrared hyperspectral imaging system was applied to obtain the intact and damaged pears at three time points (2, 12, and 24h) after compression or collision damage. After the hyperspectral images were preprocessed and feature-extracted, ImageNet was used to pre-train ConvNeXt network, and then, transfer learning strategy was applied from compression damage to collision damage to build the T_ConvNeXt model for classification. The results showed that the test set accuracy of fine-tuned ConvNeXt model was 96.88% for compression damage time. For the classification of collision damage time, the test set accuracy of T_ConvNeXt network reached 96.61% and was 3.64% higher than the fine-tuned ConvNeXt network. The number of training samples was proportionally reduced to verify the superiority of the T_ConvNeXt model, and the model was compared with conventional machine learning algorithms. This study achieved the classification of mechanical damage over time and achieved a generalized model for different damage types. The accurate prediction of pear damage time is crucial for determining proper storage conditions and shelf-life time. PRACTICAL APPLICATION: The T_ConvNeXt model proposed in this paper transferred from compression damage to collision damage effectively promoted the generality of the damage time classification model. Guidelines for choosing an effective shelf life from a commercial aspect were presented.

Design of Dendritic Promesogenic Ligands for Liquid Crystal-Nanoparticle Hybrid Systems

Liquid crystal-nanoparticle (LC-NP) hybrid systems allow synergistic interactions between LC matrixes with anisotropic alignment and NP dopants with versatile functionalities. A uniform, well-dispersed, and highly stable thermotropic LC-NP mixture paves the way for further applications. In this work, a linear promesogenic ligand and two types of dendritic promesogenic ligands with alkyl or oligo ethylene glycol (OEG) chains are designed and synthesized to facilitate incorporating NPs into the thermotropic 4-cyano-4′-pentylbiphenyl (5CB) LC matrix. A comparison study between the linear and the dendritic ligands on the capability to promote miscibility and stability of NPs in LCs is conducted. Miscibility test results show that the linear ligand and the OEG-chained dendrimer both perform well in uniformly dispersing NPs in LCs. Dynamic assemblies of NPs assisted by dendritic ligands and driven by aligning and equilibrating of mesogens are captured, showing the potential of manipulating the assembly of NPs through external thermal stimuli. The stability test shows that both types of dendrimers can significantly enhance the shelf-life time and thermal stability of NPs compared to the linear ligand. In particular, Au NPs capped with OEG-chained dendrimers are stable in 5CB for 6 months at room temperature and over 10 h at 50 °C. The synthesis of dendritic ligands is highly modulated and can be generalized onto NPs with different dimensions and properties. Tied by the dendritic promesogenic ligands, this LC-NP hybrid system with good uniformity and stability could be further applied to tunable optical displays, responsive materials, etc.