Cold Storage Period Research Articles

Effect of cold storage on some biological and physiological performance of Adalia decempunctata L.

Adalia decempunctata (L.) is a common predator in agro ecosystems. Here, the effects of low-temperature storage on biological parameters, energy reserves, and antioxidant enzymes were investigated. Eggs, larvae, and pupae of this predator were maintained for 1-4weeks and adults for different days (20, 35, 50, and 65 d) at 4, 7, and 10°C in darkness and 70±5% R.H. After storage of 20days, the survival rate in male and female insects was >90% in 4, 7, and 10±1°C. In 65days, the highest survival rate for adult insects was recorded at 4°C. Effect of cold storage on the performance of adult's A. decempunctata was not statistically different for periods up to 35days, but decreased longer duration (65days). The female adults were able to tolerate the cold storage period by producing higher amounts of glucose and antioxidant enzymes, thus displaying a high survival rate. Based on our results, maintaining A. decempunctata adults at low temperatures (i.e. 4, 7, and 10°C) for 20 or 35days performed best without loss of quality.

Textural and rheological characterisation of yoghurts produced with cultures isolated from traditional back-slopped yoghurts

Cultures isolated from artisanal yoghurts were evaluated for yoghurt production with preserved traditional properties. In this context, the textural, microbiological, physicochemical properties, and acidification kinetics of experimental yoghurt samples were evaluated and compared with yoghurts produced from commercial starter cultures for a 28-day cold storage period. All yoghurt samples completed the fermentation at a similar time. However, the B1 and K2 isolates had higher viable cell performance during the storage period, and their yoghurts had counts of Lactobacillus bulgaricus and Streptococcus thermophilus similar to those of control yoghurt samples. Also, at the end of the storage, yoghurts produced from the new isolates had higher complex modulus (G∗) than the control, except K1 + B1 yoghurts. This study demonstrated that the best results related to these parameters were obtained in yoghurts of isolates B1 and K2, and they can be recommended as potential yoghurt starters.

Mitochondria-targeted antioxidant “MitoQ” improves rooster's cooled sperm quality indicators and reproductive performance

The cell membrane of rooster sperm is sensitive to cold due to the high content of polyunsaturated fatty acids, which are very susceptible to lipid peroxidation. The present study was conducted to determine the effect of different concentrations of the mitochondrial-targeting antioxidant “MitoQ” on sperm quality and fertility potential of chilled semen in roosters. Semen samples were collected from 10 roosters, diluted in Lake extender, assigned into 5 groups according to MitoQ concentrations (0, 1, 10, 100 and 1000 nM MitoQ) and stored at 5 °C up to 48 h. Motility, mitochondrial activity, viability, membrane integrity, and lipid peroxidation were assessed at 0, 24, and 48 h of cold storage periods. In addition, the fertility potential was assessed using 24 h-cooled semen samples. Our results showed that extender supplementation with MitoQ had no effect (P > 0.05) on chilled semen samples quality parameters at time 0, while at times 24 and 48 h storage, samples contained 100 nM MitoQ presented higher (P ≤ 0.05) total motility, progressive motility, viability and membrane integrity compared to the other groups. In addition, semen samples containing 10 and 100 nM MitoQ showed higher (P ≤ 0.05) mitochondrial activity and lower (P ≤ 0.05) lipid peroxidation than other groups at 24 and 48 h storage. Fertility rate was higher (P ≤ 0.05) when the hens were artificially inseminated with 24 h-chilled semen samples containing 100 nM MitoQ. In conclusion, supplementing Lake Extender with 100 nM MitoQ could be a helpful strategy to preserve chilled semen quality and fertility potential in the rooster.

Physicochemical and Sensory Properties of Czech Lager Beers with Increasing Original Wort Extract Values during Cold Storage.

The scope of the study was the evaluation of the selected physicochemical (O2 and CO2 contents, bitterness, color, total polyphenol content (TPC), turbidity, foaming stability) and sensory properties of Czech lager beer with different original wort extract (OWE) values (OWE of 10.0; 11.0; 11.5; 12.0% w/w) during a cold storage period of 6 months (4 ± 2 °C). The length of the cold storage period did not influence the values of dissolved O2 and CO2, bitterness, color and foam stability of the samples. Contrarily, the TPC, turbidity, and sensory attributes of the samples were affected by the course of cold storage. The OWE values did not affect the development of the parameters tested. All beer samples stored until the 5th month presented "very good" sensory characteristics. Cold storage of beer is advantageous in order to maintain its freshness and sensory attributes at the highest level for the final consumer.

Identification of metabolites associated with boiled potato sensory attributes in freshly harvested and stored potatoes

Modern potato breeding programmes have to balance agronomic and consumer preferences, as they seek to develop high yielding and nutritious potatoes that are tolerant to abiotic/biotic stresses. The recent focus on consumer preference has generated sensory data to assess potato flavour intensity, umami, sweetness, sourness, bitterness and mealiness in a panel of 60 cultivated and four wild potato accessions. The potato tubers were assessed immediately after harvest and after a five-week cold storage period. The cultivated accessions included diploid landraces of S. tuberosum L. Andigenum groups Phureja and Stenotonum, diploid hybrids of these, and advanced tetraploid breeding lines. The wild accessions represented tuber-bearing Solanum species, implicated in potato domestication. Sensory data highlighted 20 advanced breeding lines that were relatively weak in potato flavour, sweetness and umami before storage, but increased to the intensities of the landrace and hybrids bred from them after storage. The data observed 39 metabolites which were significantly different between storage times (on average ≥3-fold higher) and associated with sweetness, umami, bitterness and sourness tastes. A comparison to potatoes with high potato flavour emphasised that lower levels of specific metabolites associated with sweetness (e.g. glucose, fructose, glycine and serine), sourness (oxalic, ascorbic and citric acid) and umami (aspartic acid) were related to a higher rating for potato flavour. This corroborates the hypothesis, that perception of sensory traits is based on a complex metabolic composition in potato tubers. These data also indicate that metabolomic analysis can play an important role in augmenting future breeding programmes considering consumer traits.

Changes in phenolic content, composition, and antioxidant activity of blood oranges during cold and on-tree storage

Citrus fruits are rich in phenolic compounds that possess several health benefits. However, few studies have focused on the changes in phenolic compounds in citrus fruits during postharvest storage. This study dynamically monitored the phenolic content, components and antioxidant activity of ‘Tarocco’ blood oranges during a period of 12-week cold storage and on-tree storage, respectively. We investigated the alteration mechanism of phenolic compounds in blood oranges by evaluating phenylpropanoid pathway-related enzyme activities and gene expression. Results showed that flavanones were the main phenolic compounds in blood oranges. Both storage methods mainly stimulated the accumulation of phenolic acids to improve total phenolic content, which reached the maximum at week 12. Nonetheless, blood oranges had a higher phenolic content and antioxidant activity under on-tree storage than cold storage. Furthermore, the enzyme activities and gene expression of the phenylpropanoid pathway demonstrated that the accumulation of phenolics in blood oranges during storage was highly related to the activation of the phenylpropanoid pathway. These results demonstrate that on-tree storage is a potential approach for extending the supply period of blood orange from the perspective of phenolic compounds.

Influence of Cactus Pear Mucilage-Based Edible Coating on Marketability and Edibility Parameters of Minimally Processed Loquat Fruits

Loquat fruit, popular all over the world for its mild, subacid, and sweet taste, has been classified as a non-climacteric fruit with a very short postharvest life. The fruit decays quickly after harvest, and losses in titratable acidity, taste, and juiciness, and internal browning occurs rapidly during shelf life. The aim of our study was to assess the effects of cactus pear mucilage-based coating on quality, nutraceutical value, microbiological growth, and sensorial parameters of minimally processed white-flesh Martorana and orange-red-flesh Gigante Rossa loquat fruits during cold storage. The effect of mucilage edible coating on the postharvest life, qualitative attributes, and nutraceutical value of fruit were evaluated by coloring, firmness, total soluble solids content, titratable acidity, ascorbic acid, antioxidant activity, total phenols, and total carotenoids content. Our data showed a significant effect of mucilage coating on preserving quality, nutraceutical value, sensorial parameters, and improving postharvest life of minimally processed loquat fruits. Furthermore, coated fruits showed a significantly lower microbiological growth than uncoated loquat fruits during the cold storage period. Our study suggests that minimally processing coated loquat fruit could allow producers to also sell to the market loquat fruits that present large spotted areas in the epicarp, which are usually considered unmarketable.

Hormone profiling and heat-induced tolerance to cold stress in citrus fruit

The involvement of jasmonic acid (JA), different JA-related metabolites, salicylic acid (SA), indole-3-acetic acid (IAA) and abscisic acid (ABA) in the heat-induced cross-adaptation to chilling has been investigated in citrus fruit. The effects of heating ‘Fortune’ mandarins at 37 ºC, and storing them at a chilling temperature (2 ºC) after being exposed, or not, to a heat-conditioning treatment (3 d at 37 ºC) on the levels of these signalling molecules were examined. Jasmonate metabolism activation at 37 ºC was followed by that of SA, and then by a rise in IAA and a drop in ABA. Storage at 2 ºC transiently increased the contents of IAA, of the JA precursor, cis-(+)− 12-oxo-phytodienoic acid (OPDA), and of the JA-derivatives jasmonoyl-isoleucine (JAIle) and methyl jasmonate (MeJA), and decreased ABA in the non-conditioned fruit. The results also indicated that fruit were protected from developing chilling symptoms by virtue of the heat-conditioning treatment having higher JAIle levels than the non-conditioned fruit for very long cold storage periods, while the heat-induced rises in SA, OPDA and MeJA noted in the cold-stored fruit were transient.

Investigation of the physicochemical, antioxidant, rheological, and sensory properties of ricotta cheese enriched with free and nano-encapsulated broccoli sprout extract.

This study aimed to produce the functional ricotta cheese using broccoli sprouts extract (BSE) and to evaluate its physicochemical, antioxidant, rheological, and sensory properties. The BSE nano-liposome was nano-encapsulated into basil seed gum (BSG) and was incorporated into the ricotta cheese formulation in two forms of free and nano-capsules in two levels of 3% and 5% w/w. The measurements were conducted during a 15-day storage period at 4-6°C. The results showed that the titratable acidity, hardness, and chewiness of cheeses were increased and the pH, moisture, total phenol content (TPC), and antioxidant activity were decreased (p < .05). With the addition of BSE concentration, the TPC and antioxidant activity increased significantly (p < .05) and applying the nano-encapsulation method for BSE led to better preservation of bioactive compounds. Based on the rheological results, viscoelastic solid behavior and a weak gel were observed in all cheese samples. The results of sensory evaluation demonstrated that cheeses containing free extract had lower flavor and overall acceptability scores than other samples, which indicates that the nano-encapsulation covered the undesirable flavor of the BSE. Generally, during the 15-day cold storage period, the highest sensory acceptance and functional activity were related to the samples containing nano-encapsulated BSE, especially at the 5% level.

Long-term effect of a short pulse of dietary supplementation with algae on the quality of turbot (Scophthalmus maximus) frozen fillets

This study raises the question of the potential long-term effects of a feeding pulse with diets containing algal biomass on the quality of frozen turbot (Scophthalmus maximus) fillets. A feeding trial was carried out with this aim, in which juvenile turbot were fed during 60 d with six different experimental diets, two of which were enriched with the macroalgaeUlva rigida(U diets), the other two with a microalgae blend (M diets), plus a non-supplemented control diet (CT), and finally, a commercial aquafeed (COM). Two inclusion levels were considered in algae-enriched diets (50 and 100 g kg-1) so that they were designed as U5 and U10 forU. rigida, and M5 and M10 for microalgae-enriched diets. The duration of the feeding pulse with the functional diets was 60 days, and then, all specimens were fed with a COM diet for a further 150-d period until reaching a body size close to the commercial standard (approximately 750 g). Subsequently, fish were sacrificed; fillets were removed from the pigmented flank and kept at -20 °C for 5 months. Then, fillets were thawed and the muscle proximal composition and fatty acid profile were analyzed, and fillet quality parameters were assessed during a 10-d co\ld storage period at 4°C. The possible deferred effects of algae-enriched diets on fillet quality were compared with a control diet without algae (CT) and with a commercial diet (COM). Roughly, the results obtained indicated that a 60-d administration pulse of algae-enriched diets induced some long-term changes in both the nutritional and organoleptic quality of turbot fillets. In this regard, the algae-enriched aquafeeds improved the muscle antioxidant response throughout the cold storage period, prolonging the shelf life of thawed turbot fillets. In addition, in terms of consumers’ acceptability, this feeding pulse on pre-growing stage of the productive cycle was able to modify the skin and muscle pigmentation of fish of commercial size. Namely, the U10 diet increased the protein content, improved muscle texture, reduced fillet total lipid content, and favored muscle selective retention of n-3 polyunsaturated fatty acids. On the other hand, the strategy based on the early administration of a diet rich in fishmeal (CT) for 60 d, followed by feeding with commercial feed, also affected positively the quality of fillets, with values comparable to U10 specimens. Thus, the results obtained indicate that a two-month feeding pulse with algae-supplemented diets during pre-growing phase may represent a promising strategy to improve the nutritional and organoleptic quality of frozen turbot fillet, as well as to extend their shelf life during the post-thawing cold storage.

Effects of Freezing Lycorma delicatula Egg Masses on Nymph Emergence and Parasitization by Anastatus orientalis.

Lycorma delicatula (White) (Hemiptera: Fulgoridae), native to China, was first detected in Pennsylvania, U.S. in 2014. This polyphagous pest can feed on over 70 plant species including agricultural crops, like grapes, that have high economic value. Anastatus orientalis Yang and Choi (Hymenoptera: Eupelmidae) is an egg parasitoid associated with L. delicatula egg masses in China that is being evaluated for possible introduction into the U.S. for classical biological control of L. delicatula. In support of this program, the suitability of frozen L. delicatula eggs for parasitization by A. orientalis was evaluated in a quarantine laboratory. Host egg masses held for four different cold storage periods (5°C for <1, 4, 8 and 11 months) were frozen at -40°C for 1 hour or 24 hours and exposed to female A. orientalis for parasitization for seven days. Following this experimental exposure period, rates of L. delicatula nymph emergence and A. orientalis parasitism were assessed for each of the eight different cold storage treatments. Host acceptance and suitability of frozen L. delicatula eggs by A. orientalis was assessed in terms of percentage parasitism, offspring sex ratio, and hind tibia length of emerged parasitoids. Results indicated that L. delicatula nymphs failed to emerge from eggs that were exposed to -40°C for 1 hour and 24 hours and A. orientalis could successfully parasitize L. delicatula eggs regardless of cold storage and freezing treatment. These results add a new tool for long term maintenance of L. delicatula egg masses and rearing methods for egg parasitoids of this pest. Additionally, it may be possible to field deploy sentinel eggs of L. delicatula frozen at -40°C to survey for resident natural enemy species capable of parasitizing eggs of this pest in advance of anticipated L. delicatula invasions into new areas.

Comparison of the Effects of 5-Hydroxymethylfurfural in Milk Powder Matrix and Standard Water on Oxidative Stress System of Zebrafish.

5-Hydroxymethylfurfural (5-HMF) and furfural (FF) are products of the maillard reaction (MR) in milk powder and their safety is controversial. The concentration changes of 5-HMF and FF after a period of cold storage were determined by high-performance liquid chromatography (HPLC). Then, we compared the toxicity effects of 5-HMF (2, 20, or 200 μM) in milk powder matrix and standard water on the oxidative stress system of zebrafish embryos. The results showed that the concentration of 5-HMF was stable, and the concentration of FF degraded over time. 5-HMF-exposed zebrafish embryos had a LC50 value of 961 μM for 120 h. High-concentration of 5-HMF exposure resulted in developmental toxicity and induced oxidative stress. 5-HMF exposure resulted in low expression of gstr gene at 200 μM in both matrices. Moreover, sod, cat, gstr, and gpxla genes were differentially highly expressed in other groups or showed no significant difference. Residual levels in all groups were well below the exposed dose, with a maximum value of only 0.4‰. These results provided a theoretical basis for understanding the effects of 5-HMF exposure in milk powder matrix on the oxidative stress system and suggested that the presence of 5-HMF in our daily consumption of milk powder does not produce significant toxic effects and need not be overstressed.

Antioxidant, antibacterial, and antitumor activities of goat's stirred yoghurt fortified with carob molasses

This study investigated the effects of adding carob molasses at 5 %, 10 %, and 15 % on physicochemical, rheological, and biological activities such as antioxidant, antibacterial and antitumor activities, as well as microbiological and sensory properties of stirred yoghurt samples during the cold storage period. Increasing the concentration of carob molasses increased the content of total solids (TS), titratable acidity, yellowness /blueness values, antioxidant, antibacterial, cytotoxic activity, and overall acceptability. Still, it significantly decreased the samples' ash content and water holding capacity. Furthermore, carob molasses concentration significantly affected on the fat content, viscosity, whiteness, redness /greenness values, molds, and yeast counts. In contrast, it had no significant effect on protein content, pH values, and the count of Streptococcus thermophilus and Lactobacillus bulgaricus in the stirred yoghurt containing carob molasses. The energy-dispersive spectroscopy (EDS) microanalysis of stirred yoghurt containing carob molasses showed differences in elemental content among samples. The stirred yoghurt fortified with 15 % carob molasses had the highest overall acceptability in the sensory evaluation and exhibited a higher effect in decreasing the viability of the three tested human tumor cell lines compared to the control and other treatments.

The influence of cultivation system and modified atmosphere packaging on quality attributes of tomato fruit during cold storage

ABSTRACT This study aimed to assess the effects of cultivation system (organic and conventional) and modified atmosphere packaging (MAP) treatments on quality characteristics and bioactive compounds of tomato fruit (Solanum lycopersicum cv. Şencan 9) stored in cold storage conditions, at 8°C ± 0.5°C and 90% ± 5% relative humidity, for 21 days. At the end of the cold storage period, lower weight loss and respiration rates were measured in the organically produced fruit compared with the fruit produced in the conventional production system. On day 14 and 21 of storage, higher firmness was measured in the conventional- and organic-MAP treatments and in the conventional-unwrap treatment than in the organic-unwrap treatment. On day 7, L* and hue angle measured in organic-MAP were significantly higher than in the other treatments. At the end of the cold storage period, higher soluble solids content, vitamin C, total phenolics, total flavonoids, and antioxidant activity were recorded for the organic tomatoes, compared with the conventionally grown fruit. The highest and lowest concentrations of total flavonoids and antioxidant activity were determined in organic-MAP and conventional-unwrap treatments, respectively. In conclusion, it was shown that the quality of the tomatoes grown in the organic production system and stored in MAP maintained higher quality characteristics during the cold storage period.

Effect of Pupal Cold Storage on Reproductive Performance of Microplitis manilae (Hymenoptera: Braconidae), a Larval Parasitoid of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Simple SummaryParasitoids are one of the most important biological control agents, and there are increasing requirements for long-term breeding. It is critical to figure out the parasitoid biological properties and disclose the effects of cold storage on them to extend their longevity. In this study, we investigated the field parasitism rate and clarified the biological parameters of Microplitis manilae, a dominant larval parasitoid of Spodoptera frugiperda. Further analysis revealed that the pupal cold storage, including different storage temperatures, storage period and storage time, significantly affected the emergence rate, parasitism rate and longevity of wasp adults, and the optimal storage condition was middle-aged pupae stored at 10 °C for 5–10 d. These results provide a novel insight into the mass-rearing of M. manilae and contribute to the biological control using M. manilae against S. frugiperda.As a major invasive pest in China, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) has caused great damage to crops. Hymenopteran parasitoids, especially the braconid wasps, play crucial roles in depressing pest populations. However, there was little information about the ideal storage of parasitoids to achieve their mass-rearing. Here, we identified a dominant parasitoid of S. frugiperda, Microplitis manilae (Ashmead) (Hymenoptera: Braconidae), in the Hainan province of China with a field parasitism rate of 5.66–19.10%. The investigation of biological parameters revealed that the parasitism rate of M. manilae significantly decreased with an increase in both wasp adult longevity and host age, and the wasp of 1–3 d post eclosion performed best on the first instar of host larvae, showing the highest parasitism rate. We also discovered that the decreased temperature from 30 to 20 °C greatly extended the longevity of wasp adults, and a similar result was observed after feeding on 10% sucrose water compared with sterile water. Then, the effects of different pupal cold storage temperatures (4 and 10 °C), storage period (prepupa, middle-aged pupa, late-aged pupa) and storage time (5, 10 or 20 d) on the emergence rate, parasitism rate, female proportion and longevity of M. manilae were investigated. The results demonstrated that the middle-aged wasp pupae stored at 10 °C for 5–10 d possessed a stronger parasitic ability and longer longevity. These findings may promote the flexibility and efficacy of large-scale production of M. manilae, thus contributing to its biological field control against S. frugiperda.

Effect of Silver Nitrate (AgNO3) and Nano-Silver (Ag-NPs) on Physiological Characteristics of Grapes and Quality during Storage Period

The aim of this study was to evaluate the effects of silver nitrate (AgNO3) and nano-silver (Ag-NPs) on the physiological and biochemical characteristics, and quality of grape bunches during a cold storage period. For investigations, two varieties of grapes were used, Shine Muscat and Kyoho, with different concentrations of AgNO3 and Ag-NPs on post-harvest dipping. The data indicated that AgNO3 and Ag-NPs enhanced the fruits’ longevity and quality. Depending on the data analysis, it was found that the lowest weight loss value was obtained from Ag-NP treated grapes, followed by AgNO3 treated grapes, while the highest loss occurred in the control grapes. Immersion of grape bunches in Ag-NPs was the best application for maintenance of overall storage quality for both cultivars. In the same trend, treatment with Ag-NPs produced the best results for soluble solids content (SSC), titratable acidity (TA), malondialdehyde (MDA) content, polyphenol oxidase (PPO), pyrogallol peroxidase (POD), and pectin methylestraese activity (PME). It was concluded that Ag-NPs and AgNO3 were helpful in maintaining the quality of grape bunches up to 30 days, while grape bunches under control conditions were spoiled with 30 days of cold storage.

Physiological and sanitary quality of black bean seeds dependent on storage time and initial seed moisture content

Black beans (Phaseolus vulgaris L.) are a species of great importance for family farming, both for food security and socioeconomic activity. The objective of this work was to assess the physiological and sanitary viability of black bean seeds stored with different initial moisture contents and cold storage periods. It was used a completely randomized design, 3×5 (seed moisture levels: 10, 13 and 16%, and storage periods: 0, 3, 6, 9 and 12 months in cold rooms, with four repetitions). Black bean seeds belonging to variety IPR88 Uirapuru were grown in the municipality of Santa Maria, Brazil, harvested in March 2020, and stored in a cold room (15ºC and 40% RH) in Kraft paper bags (brown type, 1.0 kg). Physiological variables and sanitary quality were assessed through laboratory tests. According to the results, it was possible to verify that the physiological and sanitary quality of black beans were negatively affected with the increase of storage period, in all grades. However, it is possible to store these seeds with moisture contents of 10 or 13% for a period of up to nine months in a cold room, with a 70% germination quality.

Ultra-high pressure-assisted preparation of cowhide gelatin as a promising fat substitute: Improve the nutrition ratio and antioxidant capacity of beef patties

In this study, low-fat beef patties were prepared by replacing different proportions of beef fat (0, 25, 50, 75, and 100%) with ultra-high pressure–assisted cowhide gelatin. The quality characteristics, lipid oxidation, protein oxidation, and fatty acid profile of beef patties during cold storage at 4 ℃ (0, 7, 14, 21, and 28 days) were evaluated. The results showed that the addition of cowhide gelatin increased the protein content and reduced the fat content of beef patties. The saturated fatty acid (SFA) content of beef patties significantly reduced and the polyunsaturated fatty acid (PUFA) content significantly increased with the increase in the replacement ratio. Especially, the 100% substitution group had the highest PUFA content; the SFA content and the n-6/n-3 ratio could be reduced by about 56% and 31%, respectively. During the cold storage period, the moisture content of beef patties increased significantly, while the cooking loss was the opposite, with the increase in the fat replacement rate. The L* and a* values of raw patties prepared with gelatin were significantly higher than those in the control group. Furthermore, adding cowhide gelatin significantly reduced the thiobarbituric acid, peroxide, and carbonyl contents of patties, but increased their total sulfhydryl content throughout the refrigeration period. Thus, it was concluded that cowhide-based gelatin was a promising alternative to replace beef fat in low-fat beef patties.

Effects of active alginate edible coating enriched with hydroxyapatite-quercetin complexes during the cold storage of fresh chicken fillets

Alginate edible coatings enriched with quercetin glycosides and hydroxyapatite/quercetin complexes were evaluated as effective active coatings able to slow down the spoilage of fresh chicken fillets during the cold storage. Hydroxyapatite/quercetin complexes were preliminarily analysed by SEM, FTIR and zeta potential. Then alginate coatings were characterized for their ability to release quercetin in an aqueous medium which represents the base condition during the development of active edible food packaging. The microbiological parameters (total viable count, psychotropics bacteria count, Pseudomonas spp. and Enterobacteriaceae), measured during the cold storage period at 6 °C, highlighted the capability of alginate coatings with hydroxyapatite/quercetin glucosides complexes to significantly inhibit the growth of spoilage bacteria, as well as the total volatile basic nitrogen during the cold storage period of 11 days. Likewise, the texture, colour and sensory parameters pointed out a positive effect of quercetin when complexed with hydroxyapatite to maintain the quality of fresh chicken fillet during the storage.

Examining the individual and additive effects of cold storage and CO2 narcosis on queen survival and reproduction in bumble bees

Diapause is a pre-programmed arrest of development allowing insects to survive in unfavorable environments. In adult insects, diapause termination is often followed by a reallocation of macronutrients and a transition to reproduction, and in some insects, this transition can be achieved using narcosis with CO2. However, whether CO2narcosis and diapause act in concert to affect reproduction remains unknown. Here, we investigated the separated and combined effects of diapause and CO2on female reproduction in queens of the common eastern bumble bee Bombus impatiens. Queens were treated with CO2 following a cold storage period (zero days, two weeks, two and four months) and were compared with untreated queens at the same timepoints for survival, colony initiation, egg-laying latency, and offspring production. We found that both CO2 and a period of at least two months in cold storage induced a transition to egg laying in gynes, and as expected, survival decreased with cold storage length. When CO2 and cold storage were combined, CO2narcosis positively affected egg laying in the earlier timepoints but its impact diminished following a longer cold storage. These data suggest that the impacts of CO2narcosis and cold storage are partially additive, and application of CO2 is effective only after a short cold storage. It further demonstrates that CO2 has complex effects on insect reproduction that are independent from diapause.