Storage Lives Research Articles

Biofumigation activities of volatile compounds from two Trichoderma afroharzianum strains against Fusarium infections in fresh chilies.

Two Fusarium fungi, F. oxysporum and F. proliferatum, have been recognized as major pathogenic fungi that cause postharvest decay of chili fruits. Ozone and some toxic chemicals are used to control pathogenic infections, leading to longer storage lives of agricultural commodities. However, these chemicals may pose some risks to the applicators and the environment. Therefore, alternative, easy-to-use fumigants for effective control of Fusarium infections in harvested fresh chilies are needed. Two endophytic fungi, Trichoderma afroharzianum strain MFLUCC19-0090 and T. afroharzianum strain MFLUCC19-0091, were isolated from Schefflera leucantha leaves. Their volatile compounds were investigated for antifungal activities against F. oxysporum and F. proliferatum. In vitro results showed that the volatile compounds produced by each strain inhibited pathogen growth. Additionally, the Trichoderma-derived volatile compounds significantly reduced Fusarium-related disease severity and incidence percentages in the inoculated fresh chilies. Antifungal properties of the volatile compounds were found to be specific to the species of the tested pathogens (MFLUCC19-0090 greatly suppressed F. oxysporum and MFLUCC19-0091 greatly suppressed F. proliferatum). Seventy-three volatile compounds were detected from both strains. Among the major volatile compounds detected, phenyl ethyl alcohol was found to possess the strongest antifungal activity against both pathogens. These Trichoderma-derived volatile compounds may be used as alternative fumigants for controlling Fusarium rot in harvested fresh chilies. The successful use of volatile compounds as biofumigants can prevent significant market losses and, more importantly, may reduce the health hazards caused by Fusarium-associated mycotoxin exposures among consumers. © 2021 Society of Chemical Industry.

Editorial: Seed Science and Technology. Volume 49 Issue 1 (2021)

At the time of writing, in the UK and Northwest Europe the wood anemone (Anemone nemorosa L., Ranunculaceae) is in full flower, as Spring gets under way. This common herbaceous perennial of woodland and hedgerows is a possibly somewhat extreme example of the challenges facing conservationists striving to preserve seeds of their native species, in all their diversity, ex situ in conventional seed banks. Its seeds will survive drying, but only after the achenes, still green when shed, are dispersed from the parent plant. Ali et al. (2007) observed an initial increase in desiccation tolerance, followed by a decline; and the proportion of seeds surviving desiccation and their increase in subsequent longevity coincided with the growth and development of their embryos ex planta. However, developmental arrest of the embryo was not required for the acquisition of desiccation tolerance, and continued growth and development of the embryo resulted in loss of desiccation tolerance, analogous to that seen in orthodox (sensu Roberts, 1973) seeds upon radicle emergence. Consequently, the window of desiccation tolerance and maximum potential longevity is comparatively short; and in nature occurs when seeds are on or close to the soil surface. Though the seeds can be air-dried with care and stored at sub-zero temperatures, high initial viabilities are difficult to achieve and their storage lives are short (ten years or less under conventional seed bank conditions); throwing doubt on the role of conventional seed banking as a means of long, or even medium-term ex situ conservation for this species. Furthermore, while A. nemorosa seeds, like those of many species from the Ranunculaceae, might be described as having morphological or morphophysiological dormancy (Baskin and Baskin, 2014), the observed lack of developmental arrest is somewhat at odds with most definitions of dormancy.

The Effects of Pore Size on Electrical Performance in Lithium-Thionyl Chloride Batteries

Lithium-thionyl chloride batteries possess the highest specific energies of all of those commercially available batteries. These batteries also have high operating voltages, with stable outputs, wide operating temperature ranges, long storage lives, and are of low cost. The main limitation of lithium-thionyl chloride batteries is the low discharge capacity at high discharge rates, which limits their commercial uses. In this study, a porous cathode carbon support was prepared by introducing ammonia bicarbonate as a pore-forming agent. The porous cathode carbon support that formed was systematically characterized by BET, SEM, and XRD. The porous carbon support was then assembled into an ER18505M battery system to characterize the electrochemical performance of the battery. The effect of pore structure on the electrochemical performance was determined and revealed the preparation of a high capacity lithium-thionyl chloride battery with a high discharge rate.

Growth of Carnobacterium spp. isolated from chilled vacuum-packaged meat under relevant acidic conditions

Carnobacterium spp. are frequently isolated from vacuum-packaged (VP) meat. Specific strains of Carnobacterium and their growth characteristics may be associated with the storage life of such products. This study investigated the growth of 44 Carnobacterium isolates obtained from VP meat cuts produced at three Canadian abattoirs (A, B and C) under the following conditions: pH 5.4, 6.2 and 7.4; lactic acid at 60 and 90 mM; acetic acid at 33.6 mM. Whole genome sequencing was performed for all 44 isolates and a core genome phylogenetic tree was created to identify strain variability among isolates from different abattoirs. The isolates were clustered into 11 groups. All isolates from abattoirs B and C were identified as C. divergens, while the isolates from abattoir A included both C. maltaromaticum and C. divergens at equal proportions. C. divergens isolates from abattoir A belonged to two phylogenetic groups and none of them was found in the phylogenetic groups containing isolates from abattoirs B or C. Whole genome sequencing revealed that identical strains were isolated from different samples obtained at the same abattoir. The mean growth rate and maximum population density of the C. maltaromaticum isolates were lower than those of the C. divergens isolates. C. divergens isolates from abattoir A had higher growth rates and maximum population density than those from abattoirs B and C. In conclusion, growth characteristic and whole genome analysis both demonstrated strain variability of Carnobacterium among abattoirs, which could be a result of the difference in the antimicrobial interventions used for carcasses at different abattoirs, and may be associated with different storage lives of VP meats produced from different abattoirs.

A new method for polydimethylsiloxane (PDMS) microfluidic chips to maintain vacuum-driven power using Parylene C

A novel method for making Parylene C-coated PDMS microfluidic chips is presented for the first time here. This method can maintain the vacuum-driven power of PDMS microfluidic chips for more than 30days. Parylene C membrane has quite low permeability to water vapor and gases such as nitrogen and oxygen. In addition, Parylene C membrane is transparent and has chemical inertness. Thus, the detection of reaction results on the chip would not be affected. The investigated results showed that a thicker Parylene C membrane and a thicker PDMS microfluidic chip resulted in a longer vacuum holding time. Digital polymerase chain reaction (dPCR) analyses were used to verify that the new method would not influence the biochemical analyses in these microfluidic chips. Furthermore, the evacuation process and Parylene C coating process can be carried out at the same time, and the operation is quite easy. This new method prolongs greatly the storage lives of vacuum-driven PDMS microfluidic chips, and will make them become widely accepted in point-of-care diagnostics.

Pre-harvest 1-methylcyclopropene application affects post-harvest physiology and storage life of the cut rose cv. Carola

We evaluated and optimized the effects of an alternative pre-harvest application of the non-toxic ethylene action inhibitor 1-methylcyclopropene (1-MCP)on the physiology and storage life of the cut rose (Rosa hybrida) cv. Carola. Cut rose was treated with a single pre-harvest liquid formula spray of 10 μL·L-11-MCP or a single treatment of a modified atmosphere packaging of 50-μm thick polyethylene film (PE50), or a combination of the two (1-MCP+PE50), and the effects on vase life, storage life, and cold storage senescence related physiological changes were evaluated. Cut rose subjected to the pre-harvest 1-MCP spray treatment had the longest storage life (26 days), while those subjected to PE50, 1-MCP+PE50, and the untreated control treatment had mean storage lives of 22, 19, and 16 days, respectively. Additionally, the pre-harvest 1-MCP spray treatment significantly extended the vase life of cold-stored flowers for zero or six days, by 27.08% and 42.55%, respectively. The pre-harvest spray treatment significantly suppressed respiration intensity, ethylene production, soluble protein degradation, 1-aminocyclopropane-1-carboxylic acid (ACC) production, and ACC oxidase activity. The 1-MCP+PE50 treatment compromised all the effects of the 1-MCP treatment except the effect on soluble protein content. We conclude that a pre-harvest 1-MCP spray treatment has positive effects on the vase life and storage longevity of cut rose, and that combining this treatment with a PE50 package diminishes these effects.

Effects of Cooling Delays at the Wholesale Market on the Quality of Fruit and Vegetables after Retail Marketing

In commercial practice, fruit and vegetables are often stored at wholesale markets or supermarket logistics centers at ambient temperatures for certain times before retail marketing. We examined the effects of keeping various fruits (apples, bananas, peaches and grapes) and vegetables (tomatoes, cucumbers, peppers and cabbages) for various periods of 0, 24, 48 or 72 h under cooling (6C), air conditioning (22C) or ambient temperatures (25–28C) on produce quality after a simulated retail marketing period of 3 days under air conditioning temperatures in the retail shop and 3 more days of refrigerated storage in the consumer's home. In general, prolonging the storage of the produce at the wholesale market, especially without proper cooling, led to increases in weight loss, decreases in firmness and flavor acceptability, changes in color, and increases in decay and physiological disorders. However, the observed effects depended on the tested produce. Practical Applications The present study demonstrated that in order to maintain produce quality and reduce postharvest losses, it is necessary to limit the storage of common commercial fruits and vegetables in wholesale markets or supermarket logistics centers to the minimum needed and not longer than 24 h. In case produce must be held in wholesale markets or supermarket logistics centers, it is necessary to store it at low cooling temperatures and not at air conditioning or ambient temperatures. Furthermore, we suggest that by means of proper logistics management, especially by ordering the proper amounts of produce, it will be possible to reduce the amounts of fruits and vegetables that are unnecessarily stored in wholesale markets or supermarket logistics centers, and thereby reduce the decline in quality and the extent of postharvest losses. Special attention must be given to susceptible produce with short storage lives, such as bananas, cucumbers and tomatoes.

Thermal kinetic performance and storage life analysis of a series of high-energy and green energetic materials

The thermal kinetic performance and storage life of tris(carbohydrazide)manganese(II) perchlorate (GTM), tris(carbohydrazide)nickel(II) perchlorate (GTN), tris(carbohydrazide)zinc(II) perchlorate (GTX), and tris(carbohydrazide)cadmium(II) perchlorate (GTG), as important high-energy and green materials, were carried out by the DSC, (thermogravimetric) TG, and a dynamic pressure measuring thermal analysis (DPTA) method. The thermal behavior, kinetics, thermal safety, and storage life of them were investigated. The results show that there are three mass-loss stages in TG curves, and one endothermic peak and two exothermic peaks in DSC curve for them. The first mass-loss stages are the melting processes, and the thermal decompositions have happened in this stage. The kinetic data were obtained from the DSC and TG curves by integral and differential methods. The most probable kinetic models and kinetic equations were suggested by polynomial fitting the kinetic data. The specific heat capacity was determined with theoretical calculation method, and then self-accelerating decomposition temperature (TSADT), thermal ignition temperature (TTIT), critical temperatures of thermal explosion (Tb), and the adiabatic time-to-explosion (tTIAD) are calculated, respectively. The storage lives of 0.01 % conversion rate for GTM, GTN, GTX, and GTG at 25 °C are 4.52a (annual), 9.26a 10.75a, and 7.57a. GTX is the most excellent carbohydrazide perchlorate.

Reducing domestic food waste by freezing at home

It is estimated that over 630,000 tonnes of ‘freezable’ food, worth up to £2.3 billion, are thrown away by UK consumers each year due to having passed labelled ‘use by’ dates or being perceived to have spoilt. Much of this food could instead have been frozen for later consumption, but research has shown that consumers are often uncertain about suitability of products for home freezing. A two-part study was therefore undertaken, starting with a literature and internet-based information review which found that although the majority of products are reported as suitable for home freezing, there is conflicting advice on some products and also marked differences between reported storage lives. As increased use of freezers would lead to greater energy consumption, the review was followed by an experimental assessment which found that the value and carbon dioxide emissions associated with the saved food far outweighed those associated with the additional energy.

Reducing domestic food waste by lowering home refrigerator temperatures

Domestic refrigerators often operate at temperatures which are higher than ideal for chilled food storage, with several studies finding averages around 7 °C. Reducing temperatures for example to 4 °C could significantly extend storage lives, giving greater opportunity for use before disposal. However, the savings in costs and emissions associated with reduced waste must be balanced against those associated with increased energy consumption at lower temperatures.Based on published storage lives of foods which are currently refrigerated and UK waste statistics, reducing from 7 °C to 4 °C could save £162.9 m of waste annually, with associated emissions of 270,000 tonnes CO2e. Including certain foods which are not always refrigerated and removing others which do not benefit from refrigeration, the estimated savings increased to £283.8 m and 578,383 tonnes CO2e. Based on experimental assessment, the costs and emissions associated with increased fridge energy consumption were considerably lower at £80.9 m and 367,411 tonnes CO2e.

The Effects of Adding Melamine at Different Resin Synthesis Points of Low Mole Ratio Urea-Melamine-Formaldehyde (UMF) Resins

Low mole ratio urea-melamine-formaldehyde (UMF) resins synthesized with 2.5% and 5.0% melamine levels added at the beginning, middle, and end points of the first alkaline step of the typical urea-formaldehyde (UF) resin synthesis procedure were compared with typical UMF resins synthesized with melamine additions made at the final alkaline step. Various resin analysis, particleboard preparation, physical performance, and formaldehyde emission level tests were carried out. UMF resins synthesized with melamine additions at the beginning of the first alkaline step showed adequate storage lives of 2 to 3 weeks, and their particleboard bonding tests showed small but significant improvements in water soak test values, while formaldehyde content values were slightly higher in comparison with typical UMF resins. The particleboards showed adequate board strength and the formaldehyde contents were relatively low to qualify for the E1 Class of European Standards. UMF resins synthesized with melamine addition made at the middle and end of the first alkaline step were highly turbid and showed chemical structure differences and very short storage lives and the resin synthesis procedures were concluded to be of little practical value.

Storage lives of Canadian vacuum packed boneless and bone-in cuts of beef

Storage lives of Canadian vacuum packed boneless and bone-in cuts of beef

Physico-chemical and sensory quality of fresh cut papaya (Carica papaya) packaged in micro-perforated polyvinyl chloride containers.

Papaya cubes at maturity stages, 5-45% yellow (more green than yellow) and 55-80% yellow (more yellow than green) were washed with 5% H2O2, drained and packaged in PVC trays having five, seven and ten micro-perforations and stored for 19days. PVC trays with 3mm diameter punch holes were used as the control. Based on physico-chemical properties, optimum maturity for papaya and micro-perforation level of PVC trays were determined. Effectiveness of citric acid in prevention of browning was also tested. Firmness and TSS changed significantly, on day 19. O2, CO2 and C2H4 concentration changed 2.4 to 4.2%, 23.4 to 5.9%, and 0 to 0.13% respectively, from day 3 to 19. pH and titratable acidity did not change significantly throughout the storage. Pretreated papaya cubes, packaged in PVC trays with ten micro-perforations, kept under 4°C had storage lives of 19days.

Research of Step-down Stress Accelerated Degradation Data Assessment Method of a Certain Type of Missile Tank

The performance degradation rates of the missile tank are generally time-varying functions uneasily evaluated by general classical evaluation methods. This paper develops a segmented nonlinear accelerated degradation model (SNADM) based on the equivalent method of accumulative damage theory, which tackles the problem that product life is difficult to be determined with degradation rate being a function of the variable of time. A segmented expression of the function of population accumulative degradation is derived. And combined with nonlinear function, an accelerated degradation function, i.e., SNADM is obtained. The parameters of the SNADM are identified by numerical iteration, and the statistical function of degradation track is extrapolated. The reliability function is determined through the type of random process of the degradation distribution. Then an evaluation of product storage life is undertaken by combining the statistical function of degradation track, reliability function and threshold. An example of a missile tank undergoes a step-down stress accelerated degradation test (SDSADT), in which the results with the SNADM and the classical method are evaluated and compared. The technology introduced is validated with the resultant coincidence of both evaluated and field storage lives.

Anomalous but useful behavior of epoxy adhesive system

Freeze storage of adhesives has been an industry-wide practice for a long time. However, when the technique was applied to an epoxy adhesive, anomalous, but very useful results were obtained. Among other observations, the study showed that freeze storage changes the final properties of the epoxy. The epoxy was applied as an adhesive in the sealing of a component. Among adhesive candidates that were evaluated, the epoxy EA9396 was preferentially selected because it is amenable to room temperature cure and consequently it exhibits less stress and fracture upon cure. The formulation was frozen at −43 °C for different periods of time. A cure schedule consisting of 16 h at room temperature followed by two hours at 65 °C imparted shore D hardness of 80, shear strength of about 1800 psi and an extent of cure of 82% to the adhesive regardless of the length of the freezing time. Rheometry analysis of the thawed frozen formulation showed an anomalous trend whereby the pot life increased immensely in direct proportion to the duration of the freezing time. In this study pot life implies the working life after the frozen formulation is thawed. A pot life of 85 min was observed for samples cold-stored for three weeks. This method would offer advantages in applications requiring long pot and cold storage lives. This paper provides an insight into this phenomenon.

Postharvest Longevity and Responsiveness of Guava Varieties with Distinctive Climacteric Behaviors to 1-Methylcyclopropene

The local guava (Psidium guajava) variety cultivated in Israel, named Ben Dov, emits a strong odor and suffers from a short postharvest life. To address these problems, we initiated a guava breeding program, and identified two new varieties, the pink-flesh King and the white/yellowish-flesh Omri, that have much better storage lives and emit fewer odors. Physiological characterization of their ripening process revealed that the traditional variety Ben Dov exhibited a classic climacteric behavior, whereas the new variety King had a suppressed-climacteric phenotype, and Omri was apparently nonclimacteric and did not exhibit any increases in respiration and ethylene production rates during ripening. Furthermore, differing concentrations of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) were required to inhibit ripening in the various varieties: a high 1-MCP concentration of 500 nL·L−1 was required to delay ripening and to prolong postharvest storage life of the climacteric variety Ben Dov; a moderate concentration of 250 nL·L−1 inhibited ripening of the suppressed-climacteric variety King; and a low concentration of just 100 nL·L−1 was sufficient to inhibit ripening of the nonclimacteric variety Omri. The results of this study indicate that different guava varieties may pursue distinctive climacteric behaviors: the suppressed-climacteric variety and, to a greater extent, the nonclimacteric variety, have longer storage lives and are more sensitive to 1-MCP than the traditional variety.

Postharvest Longevity and Responsiveness of Guava Varieties with Distinctive Climacteric Behaviors to 1-Methylcyclopropene

The local guava (Psidium guajava) variety cultivated in Israel, named Ben Dov, emits a strong odor and suffers from a short postharvest life. To address these problems, we initiated a guava breeding program, and identified two new varieties, the pink-flesh King and the white/yellowish-flesh Omri, that have much better storage lives and emit fewer odors. Physiological characterization of their ripening process revealed that the traditional variety Ben Dov exhibited a classic climacteric behavior, whereas the new variety King had a suppressed-climacteric phenotype, and Omri was apparently nonclimacteric and did not exhibit any increases in respiration and ethylene production rates during ripening. Furthermore, differing concentrations of the ethylene action inhibitor 1-methylcyclopropene (1-MCP) were required to inhibit ripening in the various varieties: a high 1-MCP concentration of 500 nL·L−1 was required to delay ripening and to prolong postharvest storage life of the climacteric variety Ben Dov; a moderate concentration of 250 nL·L−1 inhibited ripening of the suppressed-climacteric variety King; and a low concentration of just 100 nL·L−1 was sufficient to inhibit ripening of the nonclimacteric variety Omri. The results of this study indicate that different guava varieties may pursue distinctive climacteric behaviors: the suppressed-climacteric variety and, to a greater extent, the nonclimacteric variety, have longer storage lives and are more sensitive to 1-MCP than the traditional variety.

Relationship between plant stress tolerance, senescence and life span

Purpose of review: In many aerobic organisms, including fungi, yeasts, nematodes, fruit flies, mice and humans, it was found that increased resistance to stresses, especially oxidative stress, is correlated with extended longevity, which leads to the development of the “stress resistance” theory of aging. Nevertheless, very little is yet known regarding the accuracy of this theory in plants. Here we review recently accumulated evidence supporting the existence of tight correlation between stress tolerance and onset of senescence and determination of life span in plants, which supports the applicability of this theory to plants. Findings: Certain lines of evidence reveal the correlation between plant stress tolerance and regulation of senescence and life span. Firstly, it was found that the Arabidopsis delayed leaf senescence mutants ore1, ore3 and ore9 and the long-lived mutant gigantea exhibit enhanced tolerance to oxidative stresses. Secondly, transgenic cotton plants overexpressing the GF14 λ regulator gene and Arabidopsis plants overexpressing the CBF2 transcriptional activator gene are more tolerant to drought and freeze stresses, respectively, and also show delayed leaf senescence phenotypes and enhanced life spans. Thirdly, Arabidopsis mutants deficient in vitamin C (vtc1) or vitamin E (vte2) are sensitive to oxidative stress, and exhibit premature senescence and reduced seed longevity, respectively. Together, these findings suggest a tight link between stress resistance and longevity in plants, similar to what has been hypothesised in animals. Direction for future research: Confirmation of the correlation between plant stress tolerance and regulation of senescence and life span opens the possibility of using this knowledge in future research and in breeding programs in order to develop new horticultural cultivars with enhanced tolerance to environmental stresses that will most likely include phenotypes with extended longevity and delayed senescence. Such cultivars will obviously have much improved postharvest storage lives and will suffer less from damage caused by accelerated senescence.

Synergistic effects of modified atmosphere and minimal processing on the keeping quality of pre-cut papaya (Carica papaya L.)

SummaryPre-cut papaya is a highly perishable product and requires suitable pre-treatment and storage protocols for commercial utilisation. Papaya was peeled, cut into slices (5 cm 0.6 cm 0.7 cm) and surface sanitised with chlorinated water (0.1 g l–1). The slices were then subjected to minimal processing pre-treatments with a tissue firming agent (1 g l–1 CaCl2) for 10 min, anti-microbials (0.4 g l–1 potassium sorbate and 0.4 g l–1 sodium benzoate) and anti-browning agents (0.2 g l–1 ascorbic acid) for 30 min, followed by acidification (7.0 g l–1 citric acid) for 2 min. The pre-treated slices were kept under UV light (2.5 kJ m–2 for 10 min) and subsequently packed in a modified atmosphere (3% O2 + 6% CO2 + 91% N2) under partial vacuum (30 kPa), or in air, in polyethylene (PE) pouches (12 cm 10 cm; 25 µm thick; 100 g fill-weight) or in polyethylene terephthalate (PET) bottles (2 l; 500 g fill-weight) with a 2.25 cm2 silicone membrane diffusion window. Samples were stored at 6° ± 1°C and analysed for changes in their physico-chemical, microbiological and sensory attributes, along with their head-space gaseous composition. The pre-treatments acted synergistically with the modified atmospheres to stabilise the papaya slices, physiologically, as well as restricting the proliferation of microbes (e.g., total plate counts of coliforms, yeasts and moulds). Physiological stability was characterised by a significant (P < 0.05) reduction in respiration rate, reduced losses of texture and ascorbic acid, delayed increases in electrical conductivity and in colour co-ordinates, without impeding the sensory quality of the product. Pre-treated papaya slices, kept under different modified atmospheres, had storage lives of 44 – 60 d at 6° ± 1°C, which may facilitate bulk storage and long-distance transportation.

The use of a supercooling refrigerator improves the preservation of organ grafts

Current medical transplantation confronts major problems such as the shortage of donors and geographical restrictions that inhibit efficient utilization of finite donor organs within their storage lives. To overcome these issues, expanding organ preservation time has become a major concern. We investigated whether a strategy which best preserves organ grafts can be achieved by the use of a newly developed refrigerating chamber, which is capable of establishing a supercooled and unfrozen state stably by generating an electrostatic field in its inside. When adult rat organs such as heart, liver, and kidneys were stored in the supercooled conditions, the levels of major biochemical markers leaked from the preserved organs were significantly lower than in the ordinary hypothermic storage. No apparent tissue damages were observed histologically after the supercooled preservation. Our results suggest that the use of this supercooling refrigerator improves organ preservation and may provide an innovative technique for human organ transplantation.