Shelf Life Research Articles

Acetic and citric acids effect the type II secretion system and decrease the metabolic activities of salmon spoilage-related Rahnella aquatilis KM05

Rahnella aquatilis causes seafoods to spoil by metabolizing sulfur-containing amino acids and/or proteins, producing H2S in products. The type II secretion system (T2SS) regulates the transport of proteases from the cytoplasm to the surrounding environment and promotes bacterial growth at low temperatures. To prevent premature fish spoilage, new solutions for inhibiting the T2SS of bacteria should be researched. In this study, global transcriptome sequencing was used to analyze the spoilage properties of R. aquatilis KM05. Two of the mapped genes/coding sequences (CDSs) were matched to the T2SS, namely, qspF and gspE, and four of the genes/CDSs, namely, ftsH, rseP, ptrA and pepN, were matched to metalloproteases or peptidases in R. aquatilis KM05. Subinhibitory concentrations of citric (18 µM) and acetic (41 µM) acids caused downregulation of T2SS-related genes (range from − 1.0 to -4.5) and genes involved in the proteolytic activities of bacteria (range from − 0.5 to -4.0). The proteolytic activities of R. aquatilis KM05 in vitro were reduced by an average of 40%. The in situ experiments showed the antimicrobial properties of citric and acetic acids against R. aquatilis KM05; the addition of an acidulant to salmon fillets limited microbial growth. Citric and acetic acids extend the shelf life of fish-based products and prevent food waste.

Indole Schiff Base Complex: Synthesis and Optical Binding Investigation with Biogenic Amines.

Biogenic amines, produced by bacterial enzymatic reactions in food storage or processing, serve as indicators in food processing industries to assess food quality and freshness. Biogenic amines also often associated with various health problems, including abnormal immune responses and gastrointestinal disease. Previously, salphen base complexes have been reported but still exhibited low fluorescence enhancement upon biogenic amines. This research focused on synthesizing and characterizing new Zn(II) Schiff base complex with indole sidechain to enhance the fluorescence property and exploring their binding behaviour with the biogenic amines, which were phenylethylamine and cadaverine. The Zn(II) indole Schiff base complex's structure was verified by diverse spectroscopic techniques. Then, the binding behaviours between the Zn(II) indole Schiff base complex with the biogenic amines were analyzed using UV-Vis, fluorescence spectroscopy, and Job's plot analysis. UV-Vis binding study results indicated that the synthesized complexes could bind stronger with phenylethylamine than cadaverine, with binding constant, Kb= (8.21 ± 0.58) × 104 M- 1 and (2.506 ± 0.004) × 104 M- 1 respectively. Moreover, Zn(II) indole Schiff base complex-phenylethylamine binding also generated higher fluorescence enhancement than cadaverine, which were 54% and 51% respectively. Based on Job's plot analysis, the complex and biogenic amines were bound in the ratio of 1:1. To conclude, the synthesized complex has promising potential as a sensing material for biogenic amines detection in food. The complex is recommended to be deployed in the development of solid-state fluorescence sensor for biogenic amines detection for monitoring the food spoilage in the food industry in the future.

Development of an amperometric biosensor that can determine the amount of glucose in the blood using the glucose oxidase enzyme: Preparation of polyaniline-polypyrrole-poly(sodium-4-styrenesulfonate) film.

In this study, a new amperometric biosensor was developed for glucose determination. For this purpose, polyaniline-polypyrrole-poly(sodium-4-styrenesulfonate) film was prepared by electropolymerization of aniline and pyrrole with poly(sodium-4-styrenesulfonate) on a platinum plate. The best working conditions of the polyaniline-polypyrrole-poly(sodium-4-styrenesulfonate) film were determined. The glucose oxidase enzyme was immobilized by the entrapment method in polyaniline-polypyrrole-poly(sodium-4-styrenesulfonate) film. Glucose determination was made based on the oxidation of hydrogen peroxide, which is formed as a result of the enzymatic reaction on the surface of the prepared biosensor at +0.40V. The working range for the glucose determination of the biosensor was determined. The effects of pH and temperature on the response of the glucose biosensor were investigated. The reusability and shelf life of the biosensor were determined. The effects of interference in biological environments on the response of the biosensor were investigated. Glucose determination was made in the biological fluid (blood) with the prepared biosensor. This study has a feature that sheds light on biosensor studies to be developed for the detection of substances in the human body, such as glucose, uric acid, and urea. This article will set an example for future scientific research on the development of a sensor for other biological fluids in the human body, such as the sensor developed for blood samples. In addition, this developed sensor provides an innovation that improves the quality of life of patients by allowing them to constantly monitor their glucose levels and intervene when necessary.

Antimicrobial activity of eight plant essential oils having antioxidant property against spoilage microbes.

To identify efficient, broad-spectrum, and non-toxic preservatives for natural agricultural products, eight essential oils were screened for high inhibitory and antioxidant activities against spoilage microbes. The zone of inhibition test and minimum inhibitory concentration (MIC) assay were performed to assess the antimicrobial activity of eight essential oils against B. subtilis, S. aureus, Penicillium, Saccharomyces, and E. coli. Among the eight essential oils, garlic and rose essential oils exhibited the best inhibitory effects, their MICs against the spoilage microbes were 40-640 μL/L and 10-320 μL/L, respectively. In addition, the antioxidant activities of eight essential oils were compared using the DPPH and ABTS radical-scavenging assays and the reducing power assay. eight essential oils had antioxidant capacity, among which rosemary, thyme, rose, and tea tree essential oils performed best. Moreover, the combination of thyme and rose exerted stronger antioxidant activity. Therefore, the concentrations of rose and garlic, and thyme essential oils were optimized using response surface methodology to obtain the optimal composite ratios, which were 1254 μL/L, 640 μL/L, and 1228 μL/L for rose, garlic, and thyme, respectively. The DPPH free radical-scavenging rate detected using this formulation was 50.2%, basically consistent with the prediction. Zone of inhibition diameters with the compound essential oil, against five spoilage microbes, were all greater than 45mm. The essential oil combination had high antimicrobial, against agricultural product spoilage microbes, and antioxidant activities.

Enrichment of Bakery Products with Antioxidant and Dietary Fiber Ingredients Obtained from Spent Coffee Ground

Spent Coffee Ground (SCG) is the main coffee industry by-product, rich in dietary fibers and polyphenols. The extractable material of SCG was fractionated, and the phenolic compounds were identified and quantified. Chlorogenic and neochlorogenic acids were identified as the main phenolic components, and the Total Phenolic Content (TPC) of SCG was determined to be 2.16% (dry SCG basis). Furthermore, SCG was characterized in terms of Total Dietary Fiber content, which amounted to 66%. The SCG was valorized for the development of a bakery product (cookie) enhanced with fiber and bioactive polyphenols. Cookies were produced with the addition of 4% and 7% dry and defatted SCG (baked cookie basis). The produced cookie prototypes presented TPC and dietary fiber dependent on the addition level of SCG. TPC values were determined at 588 and 1017 ppm, while dietary fiber values were at 2.7 and 4.6%, respectively. The shelf life of the cookies was monitored over 143 days at three different temperatures (25 °C, 35 °C, and 45 °C) in terms of texture (hardness), color, Peroxide Value (PV), and TPC. It was observed that the PV value significantly increased in samples with incorporated SCG, stored at 45 °C, while in those stored at 25 °C and 35 °C, PV remained at low levels. The TPC of the SCG-enriched samples remained practically constant during the shelf life analysis, while color and hardness increased (mathematically modeled). SCG-added cookies were characterized by increased darkness, increased hardness, and a mild (desirable) coffee flavor. The overall sensory impression scores for 0%, 4%, and 7% SCG-added cookies were 7.5, 8.0, and 8.2, respectively. Based on sensory evaluation test results, the shelf lives of 0%, 4%, and 7% SCG at 25 °C were 359, 435, and 471 days, respectively. Overall, SCG is a potentially valuable ingredient that can be used to develop innovative food (baked) products with enhanced nutritional value and increased shelf life.

Quality and safety of cheese shipped to the United Arab Emirates

During an examination of 3299 cheeses imported into the United Arab Emirates (UAE) from 2017 to 2021 for compliance with regulations regarding moisture and fat content, microbial quality, acidity, the presence of quinoline (a non-permitted colorant), sorbic acid, and the presence of rust discoloration, it was found that 91% of cheeses were compliant with UAE legislation. However, 9% were in violation of one or more of the mandated quality parameters, suggesting that adulteration had occurred. Within product categories the greatest level of non-conformity at 13% was noted for processed cheese, primarily due to violations caused by high moisture and low-fat content. This is important because moisture levels in processed cheese can influence its texture and shelf life. The microbial assessment of cheese showed that 85.7% of semi-hard and 77.5% of soft cheeses had non-compliant levels of E. coli. It was notable that 21.8% of non-compliant products originated from Turkey. Cheeses from Germany had the lowest level of non-conformity at 0.6%. This study illustrates the need for border scrutiny to include physicochemical examinations of cheese samples. The current initiative aims to promote the need for equity in global trade and to prevent the marketing of adulterated food items.Graphical

Leveraging Observations of Untrained Panelists to Screen for Quality of Fresh-Cut Romaine Lettuce

Fresh-cut romaine lettuce’s high perishability challenges ready-to-eat (RTE) salad production. Selecting cultivars less prone to browning and decay is crucial for extending shelf life. Traditional quality evaluation methods using instrumentation and trained panelists are time-consuming and logistically complex. This study investigated the effectiveness of untrained volunteers in assessing fresh-cut romaine lettuce quality. Given that the average consumer in the USA is familiar with the flavor characteristics of romaine lettuce, this study proposed to investigate the value of having untrained volunteers discern the quality of fresh-cut romaine lettuce. Therefore, six romaine lettuce accessions (Green Forest, King Henry, Parris Island Cos, PI 491224, SM13-R2, and Sun Valley) were assessed for sensory quality attributes (browning, green color, decay, and overall quality) and compared with instrumentation analyses (gas composition including O2 and CO2, electrolyte leakage, and color). The results showed significant quality differences (p < 0.05) among the accessions, with some seasonal variability. Very importantly, the consumers’ (n = 159) assessments revealed similar results to those produced by either instrumentation or a trained panel. The consumers provided sensory scores that allowed for the grouping of accessions based on their postharvest quality, which efficiently matched their pedigree relationship. In conclusion, ad hoc consumer panels can be an effective way to characterize the quality of romaine lettuce for RTE salads.

Evaluation of Differences in Capacity of Nutrient Content Accumulation between two Ecotypes of Lotus (Nelumbo Nucifera) due to Environmental Difference in Tropical and Temperate Regions

Environmental fluctuations can amplify variations even in clonal plants. However, it is unclear whether these differences in environmental conditions can alter physiological activities of two different ecotypes of lotus. We intended to evaluate whether the difference in nutrient content accumulation capability between two ecotypes is different because of the different geographical distribution. The present study revealed us a substantial difference in capacity of nutrient accumulation of lotus (Nelumbo nucifera) due to environmental difference in tropical and temperate zone. The moisture content of lotus in the tropical region was 8.25%, whereas the temperate region was 86.04%.Maintaining a low moisture content might extend the shelf life of the seed. Crude protein and crude fibres levels were found to be high in tropical lotus (24.4% and 3.15%, respectively) and low in temperate lotus (17.50% and 2.00%). Growth amplifying environmental conditions leads to increase in production of protein content. The tropical lotus has the largest crude lipid content (3.68%), whereas the temperate lotus had the lowest (1.90%).Because of the presence of big rhizomes in temperate lotus, the amount of Ash content produced (8.00%) was about double that of tropical lotus (4.03%). Overall, the tropical lotus ecotype had the highest nutrient content accumulation for crude protein, crude fibres and crude lipids. However, temperate lotus has the highest moisture and ash content.

Nanocomposite Coatings of Pectin and Oxide Zinc Nanoparticles to Increase Papaya Shelf Life

Nanocomposite coatings functionalized with antimicrobial nanoparticles could be a promising alternative for the postharvest preservation of fruits. This study aimed to develop nanocomposite coatings based on pectin incorporated with zinc oxide (NPZ) nanoparticles to preserve the postharvest quality of papaya fruits. The coatings were prepared using pectin (3%) and NPZ (0%–0.4%). The materials were characterized for water-related properties (water solubility and water vapor permeability) as well as physical, mechanical, morphological, rheological, and structural properties. The coatings were applied to papaya fruits, which were analyzed for weight loss, firmness, titratable acidity, and soluble solids over nine days of storage. Incorporating NPZ (0%–0.4%) did not affect the films’ water solubility and vapor permeability. However, films with NPZ exhibited lower mechanical properties than pure pectin films. Rheological behavior testing indicated that the pectin solution was a Newtonian fluid, whereas pectin solutions with zinc nanoparticles were non-Newtonian fluids. The pectin coating with 0.2% NPZ was the most effective in preserving the postharvest quality of papaya by reducing fruit weight loss and acidity content. Therefore, the developed coatings incorporated with NPZ showed promise for the postharvest preservation of papaya fruits.

Research progress on the effects of postharvest storage methods on melon quality

Background As an important global agricultural cash crop, melon has a long history of cultivation and a wide planting area. The physiological metabolism of melon after harvest is relatively strong; if not properly stored, melon is easily invaded by external pathogens during transportation, resulting in economic losses and greatly limiting its production, development and market supply. Therefore, the storage and freshness of melon are the main challenges in realizing the annual supply of melon, so postharvest storage has received increasing amounts of attention from researchers. Methods This study used academic, PubMed, and Web of Science resources to retrieve keywords related to postharvest storage and melon quality; read, refined, classified, and sorted the retrieved literature; sorted and summarized the relevant research results; and finally completed this article. Results This article reviews the mechanism and effects of physical, chemical and biological preservation techniques on the sensory quality, compound contents and respiratory physiological activities of different varieties of melon fruits. When maintaining normal metabolism and not producing physiological disorders, melon inhibits cell wall metabolism, reactive oxygen species metabolism and the ethylene biosynthesis pathway, etc., to the greatest extent during postharvest storage, thereby reducing the material consumption of fruits, delaying the ripening and senescence process, and prolonging the postharvest life and shelf life. Conclusion The literature provides a theoretical basis for postharvest preservation technology in the melon industry in the future and provides corresponding guidance for the development of the melon industry.

Recent Progress on the Application of Chitosan, Starch and Chitosan–Starch Composites for Meat Preservation—A Mini Review

The preservation of meat via sustainable methods and packaging is an area of continued interest driven by the need to address food security. The use of biomaterial films and coatings has gained significant attention due to their non-toxicity and biodegradability compared with conventional synthetic films. Starch and chitosan are sustainable sources for the preparation of films/coatings owing to their relatively low cost, natural abundance derived from numerous sources, biocompatibility, biodegradability, and antimicrobial, antioxidant, and film-forming attributes. These remarkable features have notably increased the shelf life of meat by inhibiting lipid oxidation and microbial activity in food products. Furthermore, recent studies have successfully incorporated binary biopolymer (starch and chitosan) systems to combine their beneficial properties upon composite formation. This literature review from 2020 to the present reveals that chitosan- and starch-based films and coatings have potential to contribute to enhanced food security and safety measures whilst reducing environmental issues and improving sustainability, compared with conventional synthetic materials.

Advances in space food processing: From farm to outer space

Space is the final frontier and mankind has long desired to explore the vast expanse of the universe in the pursuit of finding new worlds. The need for nutritious and long-lasting food during deep space missions have however, been an impediment to this quest. Although challenging, researchers from different public and private space organizations and institutes have come together striving hard to develop food processes, product quality and safety protocols for advancing the field of space foods. Even NASA has proposed nanomaterial-based packaging to preserve space foods longer than 5 years. Therefore, a fresh outlook is required on processing and packaging technologies currently adopted for the preparation of space foods. This review provides an overview of the inception of space foods followed by its physico-chemical and microbiological quality considerations, and processing and packaging technologies. The market opportunities available for space foods has also been covered highlighting the major players in the space food processing sector. Literature review indicates that freeze-drying has been used as a space food preservation technology of choice for years, but the combination of high-pressure processing and thermal treatment is now gaining attention due to its potential in extending the shelf life of space foods upto 5 years. Besides, 3D printing has also emerged as an economically viable technology for producing more nutritious and organoleptically appealing space foods. Currently, the major constraint for space food research is simulating the environment of space for testing food processes and packaging materials which could be explored.

Comparative growth kinetics of Listeria monocytogenes and Salmonella enterica on dehydrated enoki and wood ear mushrooms during rehydration and storage

Specialty mushrooms have been implicated in foodborne illness outbreaks in the U.S. in recent years. These mushrooms are available to consumers in both their fresh and dried states. Dehydrating mushrooms is a convenient way to increase shelf life. The dehydration process results in a lowered water activity (aw) of the commodity, creating an environment where both spoilage and pathogenic bacteria cannot proliferate. Prior to food preparation and consumption, these mushrooms are typically rehydrated and possibly stored for later use which could lead to increased levels of pathogens. This study examined the survival and growth of Listeria monocytogenes and Salmonella enterica on dehydrated enoki and wood ear mushrooms during rehydration and subsequent storage. Mushrooms were heat dehydrated, inoculated at 3 log CFU/g, and rehydrated at either 5 or 25°C for 2 h. Rehydrated mushrooms were stored at 5, 10, or 25°C for up to 14 d. L. monocytogenes and S. enterica survived on enoki and wood ear mushroom types during rehydration at 5 and 25°C, with populations often <2.39 log CFU/g. During subsequent storage, no growth was observed on wood ear mushrooms, regardless of the rehydration or storage temperature, with populations remaining <2.39 log CFU/g for both pathogens. When stored at 5°C, no growth was observed for either pathogen on enoki mushrooms. During storage at 10 and 25°C, pathogen growth rates and populations after 14 d were generally significantly higher on the enoki mushrooms rehydrated at 25°C; the highest growth rate (3.56 ± 0.75 log CFU/g/d) and population (9.48 ± 0.62 log CFU/g) after 14 d for either pathogen was observed by S. enterica at 25°C storage temperature. Results indicate a marked difference in pathogen survival and proliferation on the two specialty mushrooms examined in this study and highlight the need for individual product assessments. Data can be used to assist in informing guidelines for time and temperature control for the safety of rehydrated mushrooms.

Alginate composite films incorporated with Zn-based inorganic antimicrobials for food packaging: Effects of morphology.

Biopolymers-based food packaging materials have drawn attention as potential candidates for substitution of petroleum-based materials. In this study, composite alginate films were developed by incorporating Zn-based antimicrobials to overcome the intrinsic disadvantages of alginates that hinder their wide applications. Antimicrobials with different morphologies (nanoplatelets, nanorods, and nanospheres) were employed to investigate the effects of antimicrobials' morphology on antibacterial, thermal, mechanical, and barrier performance of composite alginate films. Meanwhile, morphological and structural characterizations were carried out to explore the interactions between antimicrobials and alginate matrix. Results indicated that films with nanospheres exhibited superior antibacterial property, while those with one-dimensional nanorods possessed better mechanical and barrier performance. Besides, preliminary test on fresh-cut potatoes and chicken breasts indicated that the composite films showed potential in extending shelf life of foods. By incorporating antimicrobials with three different morphologies, this study provides particular insights into improving properties of composite packaging materials.

Early Detection of Food Safety and Spoilage Incidents Based on Live Microbiome Profiling and PMA-qPCR Monitoring of Indicators

The early detection of spoilage microorganisms and food pathogens is of paramount importance in food production systems. We propose a novel strategy for the early detection of food production defects, harnessing the product microbiome. We hypothesize that by establishing microbiome datasets of proper and defective batches, indicator bacteria signaling production errors can be identified and targeted for rapid quantification as part of routine practice. Using the production process of pastrami as a model, we characterized its live microbiome profiles throughout the production stages and in the final product, using propidium monoazide treatment followed by 16S rDNA sequencing. Pastrami demonstrated product-specific and consistent microbiome profiles predominated by Serratia and Vibrionimonas, with distinct microbial signatures across the production stages. Based on the established microbiome dataset, we were able to detect shifts in the microbiome profile of a defective batch produced under lactate deficiency. The most substantial changes were observed as increased relative abundances of Vibrio and Lactobacillus, which were subsequently defined as potential lactate-deficiency indicators. PMA-qPCR efficiently detected increased levels of these species, thus proving useful in rapidly pinpointing the production defect. This approach offers the possibility of the in-house detection of defective production events with same-day results, promoting safer food production systems.

Antioxidant and antimicrobial activities of Myrtus communis essential oils in cold-stored lactic butter.

The use of natural antioxidants and antimicrobials in dairy production can increase the variety of dairy-based products. In this study, the antioxidant and antimicrobial changes in lactic butter samples made from heat-treated creams and enriched with M. communis essential oils (EOs) were investigated. The best lactic butter properties were achieved by optimizing the process at 70 and 80 °C. M. communis EOs decreased lipid oxidation and spoilage microorganism growth in lactic butter during cold storage. M. communis EOs have antioxidant and antimicrobial activity in lactic butter equal to that of ascorbyl palmitate. α-Pinene, p-cymene, limonene, 3-carene, 1,8-cineol, β-linalool, α-terpineol and myretenol are the major contributors to the antioxidant and antimicrobial activities of M. communis EOs. They exhibit antioxidant activity by neutralizing free radicals by donating hydrogen or acting as termination enhancers, and antimicrobial activity by disruption of cell membranes, which may result in the leakage of macromolecules or the loss of essential metabolites, ultimately leading to cell death during the storage of lactic butter samples. The addition of M. communis EOs improves lactic butter stability equal to that of ascorbyl palmitate, and may be applied as a natural and effective preservative to maintain butter from lipid oxidation and microbial spoilage and enhance its safety. The growing recognition of the health benefits of natural antioxidants, as opposed to synthetic ones, has led to the development of new applications for natural antioxidants. In this regard, M. communis L. EOs can be used to enhance the shelf stability of cold-stored lactic butter. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sustainable processing technologies (pulsed light, electrolysed water and ozonation) for microbial decontamination of muscle foods

Considering the high perishable nature of muscle foods (fish, poultry and red meat) and wide diversity in spoilage microorganisms responsible for spoilage, the prevalence of pathogenic microorganisms in muscle food spoilage is significant. There has been extensive coverage on the emergence of antibiotic resistance in food spoilage microbes in recent years. Chemical preservatives have been extensively employed for the preservation of muscle foods although they have been found to cause toxicity and are not environmentally sustainable. Nevertheless, the scientific community has shown a growing interest in recent breakthroughs in the utilization of innovative clean-label technologies for the preservation of muscle meals, owing to their sustainable characteristics. Among them pulsed light, electrolysed water and ozonation have been under wide exploration. The evaluated sustainable technologies have been found to effectively inhibit the microbial spoilage and reduce the development of antimicrobial resistance. This review discusses potentiality of sustainable technologies in preserving muscle foods with minimal deteriorative impact.

Changes in raspberry sensory quality after harvest as affected by CO2 atmospheres

CO2 atmospheres have the potential to influence raspberry (Rubus idaeus L.) sensory quality after harvest. Our study determined the optimal postharvest atmosphere to extend shelf life without negatively impacting sensory quality. Raspberry fruit were stored at 5 ℃ in 15, 8, 5 or 0.03 kPa CO2 in combination with 6, 13, 16 or 21 kPa O2, respectively. A trained sensory panel conducted a descriptive sensory evaluation of the raspberry fruit after 5, 10, and 13 d of storage. Raspberries stored in 15 kPa CO2 with 6 kPa O2 (15 kPa) atmosphere followed by that in 8 kPa CO2 with 13 kPa O2 (8 kPa) atmosphere had higher firmness than that in 5 kPa CO2 with 16 kPa O2 (5 kPa) and 0.03 kPa CO2 with 21 kPa O2 (0.03 kPa) atmosphere. Panelists found that raspberries stored in 8 kPa and 15 kPa CO2 atmosphere had the least off-flavor and highest tartness. Raspberries stored in 8 kPa scored highest in raspberry flavor with substantial juiciness and sweetness scores. The fermentative volatiles acetaldehyde and ethanol were higher in raspberries stored in 15 kPa despite the low off-flavor scores, while most other raspberry volatiles decreased with increasing CO2 concentration, including flavor-related volatiles α-ionone, α-terpineol, limonene and linalool. After 10 d, the quality of raspberries stored in 0.03 kPa or 5 kPa atmosphere had degraded considerably. While 15 kPa atmosphere prolonged shelf life the longest, 8 kPa atmosphere prolonged shelf life to 10 d while maintaining sensory quality and was the best overall atmosphere.

Wax Patterns, Textural Properties, and Quality Attributes of Two Eggplant (Solanum melongena L.) Cultivars during Storage

Two eggplant cultivars (Brigitte and Dalong) were stored under ambient conditions for 8 days to examine the postharvest quality and shelf life. Results indicated that the respiration rate, firmness and springiness, and nutritional quality of both eggplant cultivars decreased with the extension of shelf life. On the contrary, opposite trends were observed in weight loss, gumminess, and chewiness of eggplant fruits. In addition, the weight loss of ‘Brigitte’ eggplant fruits was 3.3% and 6.9% lower compared with ‘Dalong’ eggplant fruits at 4 and 8 days after storage. Thicknesses of epidermal cells and the stratum corneum, the epicuticular wax content of ‘Brigitte eggplant fruits increased by 42.9%, 766.7%, and 58.8% compared with ‘Dalong’ eggplant fruits, respectively, with a concomitant increase in the dense wax layer structure. In conclusion, the storage tolerance of ‘Brigitte’ eggplant fruits was higher than that of ‘Dalong’ eggplant fruits due to the higher epicuticular wax content and dense wax layer structure.

Preparation and properties of PCL coaxial electrospinning films with shell loaded with CEO and core coated LEO nanoemulsions

During storage and transportation, the reduction of microbial contamination and management of the exudation of fluids from the fish can effectively mitigate spoilage and degradation of fish fillets. In this work, the coaxial electrospinning films loaded with natural plant preservatives, namely laurel essential oil (LEO) and clove essential oil (CEO), were prepared by the coaxial electrospinning method synergistic with nanoemulsion techniques, and the hydrophilic preservation pads were prepared. The morphology of the film fiber is clear, without beads or damage, with fiber diameters falling within the 230–260 nm range. It has a distinct core–shell structure, exceptional thermal stability, and strong antibacterial and antioxidant properties. The core–shell structure of the fiber subtly regulates the release of preservatives and significantly improves the utilization efficiency. At the same time, the synergistic use of two essential oils can reduce the amount while amplifying their effectiveness. The pads significantly slowed down the increase of key indicators of spoilage, such as total viable count (TVC), pH, thiobarbituric acid reactive substances (TBA), and total volatile base nitrogen (TVB-N), during the storage of the fish fillets. Furthermore, the pads effectively slowed down the decline in water-holding capacity, the deterioration of textural qualities, and the negative changes in the microstructure of the fish muscle. Ultimately, the pads notably delayed the spoilage of fish fillets, extending their shelf life from 5 d to 9 d. The efficient utilization of biological preservatives in this film can provide technical support for the development of food preservation materials.