Refrigeration Storage Research Articles

Characteristic analysis of compressed air energy storage system based on intermediate cooling

With the shortage of traditional fossil energy and the aggravation of global warming, the demand for transformation from traditional fossil energy to renewable energy becomes more and more urgent. Compressed air energy storage technology is a guaranteed technology to overcome the time limit of renewable energy and achieve sustainable, efficient and large-scale application of renewable resources. In order to solve the traditional compressed air energy storage technology energy output variety is single, there is low grade energy waste defects. This paper presents a compressed air energy storage system based on intermediate cooling. Through the intercooler, the system adjusts the inlet temperature of the expander, improves the output cooling quality, and realizes the coupling operation of refrigeration and energy storage. This paper establishes a thermodynamic model of the system, analyzes the effects of ambient air temperature and inlet temperature of expander on system performance, and compares the energy efficiency ratio of the system with that of compressed air refrigeration system. The simulation results show that the system can adjust the inlet temperature of expander to increase the net power consumption and achieve high quality cooling output.

Evaluation of Different Techniques, including Modified Atmosphere, under Vacuum Packaging, Washing, and Latilactobacillus sakei as a Bioprotective Agent, to Increase the Shelf-Life of Fresh Gutted Sea Bass (Dicentrarchus labrax) and Sea Bream (Sparus aurata) Stored at 6 ± 2 °C.

Simple SummaryA method of increasing the shelf life of gutted sea bass and sea bream packaged under vacuum and stored at 6 ± 2 °C (simulating supermarkets and consumer fridges) through the use of bioprotective starter cultures was studied. An increase in the shelf life up until 14 days was observed by washing the gutted fish in water supplemented with a culture of Latilactobacillus sakei and dextrose (0.1%). L. sakei reduced the growth of specific spoilage microorganisms and consequently reduced the production of total volatile nitrogen and oxidized compounds.Fish meat is very perishable because of indigenous and microbial enzymes, which determine spoilage and shelf life. The deterioration processes, which lead to an important, sequential, and progressive modification of the initial state of freshness, are fast and depend on rearing, harvesting, slaughtering, handling, and storage conditions. Usually, the shelf life of gutted fish stored at 4 ± 2 °C under vacuum packaging (VP—1.0 bar) and modified atmosphere packaging (MAP, 70% N2, <1% O2, 30% CO2) is approximately 9 days. The aim of this work was to improve the shelf life and preserve the microbiological and sensory quality of farmed gutted sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) using different methods, including VP, MAP, and bioprotective culture containing Latilactobacillus sakei, until 12–14 days. Microbiological, physicochemical, and sensory quality indices were monitored to confirm the effectiveness of biopreservation on product quality during proper refrigeration (4 ± 2 °C) or abuse (6 ± 2 °C, simulating supermarkets and consumer fridges) storage period. Considering the quality indexes represented by Enterobacteriaceae, total volatile nitrogen (TVB-N), and malonaldehyde concentrations (TBARS) and the sensorial analysis, the VP samples were more acceptable than the MAP fish, even though the shelf-life of the VP and MAP fish was similar at about 12 days. The second phase of the work was to evaluate the shelf-life of both VP fish stored at 6 ± 2 °C, which simulates the normal abuse temperature of supermarkets or consumer fridges. Data confirmed the previous results and demonstrated, despite the abuse temperature of storage, a shelf-life of about 12 days. Finally, the third phase consisted of prolonging the shelf life until 14 days of storage at 6 ± 2 °C by washing the gutted sea bass and sea bream in a suspension of bioprotective starter (7 log CFU/mL) with or without the addition of dextrose (0.1%) and by VP packaging. The bioprotective culture reduced the growth of spoilage microorganisms. Consequently, the total volatile nitrogen (TVB-N) concentration in both fish species was low (<35 mg N/100 g). Nonprofessional and untrained evaluators confirmed the acceptability of the inoculated samples by sensorial analysis.

Development of a Stepwise Algorithm for Supercooling Storage of Pork Belly and Chicken Breast and Its Effect on Freshness.

Supercooling is the method of lowering the temperature of a foodstuff below its freezing point without phase transitions. This storage technique has a potential advantage for extending shelf life. Nevertheless, the supercooled state of food is thermodynamically unstable. To accomplish supercooling storage, slow cooling rate and minimized temperature fluctuation are necessary. Thus, a stepwise cooling algorithm was designed and applied in this study. Pork belly and chicken breast were stored at 3 °C, −18 °C (freezing), and supercooling treatment was applied to them for 12 days. All samples preserved their supercooled state and were unfrozen during the storage period. Overall, supercooled samples were advantageous in respect of drip loss compared to that of frozen samples, regardless of type of sample. Total volatile basic nitrogen, total aerobic account, and cooking loss of pork belly was higher than in the chicken breast due to the high fat retention in pork belly as compared to chicken breast, in particular, at refrigerated storage condition. Samples stored at supercooling treatment prevented increase in volatile basic nitrogen and microbial growth. Therefore, the supercooled state was successful when using stepwise algorithm, and it was effective at maintaining meat quality compared to freezing and refrigeration storage.

Electrocaloric effect and high energy storage efficiency in lead-free Ba0.95Ca0.05Ti0.89Sn0.11O3 ceramic elaborated by sol–gel method

Structural, dielectric, ferroelectric, energy storage properties, and electrocaloric effect were studied in lead-free ceramic Ba0.95Ca0.05Ti0.89Sn0.11O3 (BCTSn) elaborated by the sol–gel method. Phase purity structure was confirmed from X-ray data using the Rietveld refinement analysis which revealed the coexistence of tetragonal (P4mm) and orthorhombic (Amm2) symmetries at room temperature. Phase transitions were detected by dielectric and differential scanning calorimetry measurements. The energy storage properties were determined from P-E hysteresis, and the electrocaloric properties were calculated indirectly via the Maxwell approach. The large value of electrocaloric temperature change of ΔT = 0.807 K obtained at a relatively small electric field of 30 kV cm−1, and the high energy storage efficiency can make BCTSn ceramic a promising candidate for environmentally friendly refrigeration and energy storage applications.

A novel renewable energy storage system based on reversible SOFC, hydrogen storage, Rankine cycle and absorption refrigeration system

A global shift towards a more sustainable and eco-friendly future has prominently emphasized on the need to develop cleaner and renewable energy sources for various applications in our day-to-day life. A fuel cell is an electrochemical system that directly transforms the chemical energy of the fuel into electrical power without passing through any intermittent thermal layers. As a result, the Carnot's performance has no bearing on it. High efficiency and low noise pollution are some of the key advantages of fuel cells. Power generation from fuel cells can curtail costly transmission lines and minimize the losses during the transmission for a distributed system. Moreover, the power plant size is independent of fuel cell performance. The utilization of the trigeneration system increases the efficiency of high-temperature solid oxide fuel cell because the heat dissipated by the fuel cell is now utilized for cogeneration. In this paper, energy analysis of an integrated system consisting of a solid oxide fuel cell operating in fuel cell mode and electrolyser mode coupled with Rankine cycle, metal hydride system and absorption refrigeration system for power generation, heating and cooling applications has been performed. The study shows a significant improvement in the performance of the integrated plant compared to the power generation using combination of the solid oxide fuel cell and the Rankine cycle alone. It was found that the maximum efficiency in fuel cell mode occurs at an inlet flow temperature of 900 K. The net efficiency with and without organic Rankine cycle (ORC) in this case is estimated to be 44.41 % and 40%, respectively. However, maximum net efficiency occurs at a current density of 0.6 A/cm2, wherein efficiency with and without ORC is 46.54 % and 45.84%, respectively. In the electrolyser mode, the maximum overall efficiency of the system was observed to be 88.82 %.

The Effect of Peppermint Essential Oil and Nisin on Listeria monocytogenes Inoculated in Minced Meat of Silver Carp

Listeria monocytogenes is one of the most important food-borne pathogenic bacteria and now its control is the most important challenge in food industry plants. The aim of this study was to evaluate the effect of peppermint essential oil and Nisin in controlling the growth of L. monocytogenes in minced meat of silver carp in the first, L. monocytogenes bacteria (3log/g) were inoculated to minced meat of silver carp, then peppermint essential oil (0/005 to 4%) and Nisin (2.5 to 70 μg/g) were added to samples separately as well as in various concentrations in order to inhibit of L. monocytogenes bacteria. L. monocytogenes was counted in 0, 1, 3, 5, 7, 9, 12, 15, and 21 days during storage refrigerator. The results showed that in the separate concentration, adding 4 % of peppermint essential oil and 40 μg/g of Nisin on minced meat of silver carp were effective. On the other hand, the combination of 0.5 % peppermint essential oil and 40 μg/g of Nisin had excellent inhibitory effects on the growth of L. monocytogenes. Therefore, the results indicated that peppermint essential oil and Nisin could be used as a natural preservative in controlling and inhibiting of L. monocytogenes bacteria.

Ascertaining the refrigerated storage life of wheat bran and grape seed extract enriched meatballs (Goshtaba) under aerobic conditions

Three types of meatballs (Goshtaba) viz. control, dietary fiber (8% hydrated wheat bran) rich and anti-oxidant rich (0.1% grape seed extract) Goshtaba were prepared from good quality mutton, packaged in low density polyethylene pouches (LDPE-200µm gauge) and analyzed during its refrigerated storage (4±1◦C) to ascertain their aerobic refrigerated storage life. The emulsion stability and cooking yield of the dietary fiber rich product was improved. The pH of dietary fiber rich product increased significantly (P≤0.05), while as that of antioxidant rich Goshtaba decreased significantly (P≤0.05) with the increase in the storage period. The water activity of all the samples showed an increasing trend over the storage period. The microbial parameters (total plate count, psychrophilic count) increased during the storage period, but the values were decreased in the product fortified with grape seed extract (GSE), depicting an anti-microbial effect of GSE. The sensory quality was decreased in all the products with increase in storage life, but the rate of decline was slowest in GSE treated meatballs. It was concluded that the product treated with GSE as anti-oxidant source retained most of the desirable properties during the aerobic refrigerated storage for at least 26 days as against 17 days in case of other products.

Behaviour of Rista (meatballs cooked in spiced curry) under aerobic refrigerated storage conditions

The present study was conducted to study the effect of aerobic packaging system on the storage stability of Rista (meatballs cooked in spiced curry) under refrigeration temperature. A total of three types of Rista developed including: T0 as control Rista (lean meat: animal fat = 90:10 in the formulation), T1 as fiber rich Rista (lean meat: animal fat: Hydrated Wheat Bran=82:10:8 in the formulation) T2 as antioxidant rich Rista (lean meat: animal fat=90:10 in the formulation and fortified with 0.1% Grape Seed Extract) were packaged aerobically in LDPE pouches and stored at refrigeration temperature (4±1oC). The samples were analysed during storage (on days 0, 7, 10, 13, 16, 19). The results revealed that the emulsion stability (%), cooking yield (%), pH and water activity presenting the mean of 93.67, 95.61, 94.47; 91.59, 95.49, 93.38; 6.29, 6.65, 6.54 and 0.98, 0.99, 0.99 in T0, T1 and T2, respectively. The sensory values for various sensory parameters viz appearance, flavour, texture, saltiness and overall acceptability followed a decreasing trend with the storage. The microbial parameters like Standard Plate Count (SPC) increased significantly throughout the storage period; Total Psychrotrophic Count (TPSC) was detected from 13th day of storage and Coliform Count was not detected throughout the storage period. The observations concluded that the product can be stored in aerobically packaged LDPE pouches for 16 days without much change in physicochemical, microbiological and sensory properties at refrigerated storage.

Evaluation of Aerobically Packaged Fibre Enriched Low Fat Kadaknath Chicken Patties under Refrigeration Storage

The fibre enriched low fat kadaknath chicken patties were packaged aerobically and evaluated for storage stability under refrigeration. The pH, TBA and FFA values of treated patties were lower as compared to control throughout the storage. A progressive and significant (P<0.05) increment in the pH, TBA and FFA values of control as well as fibre enriched low fat kadaknath chicken patties were observed with the advancement of storage in aerobically kadaknath chicken patties. The total plate count (TPC) followed a significantly (P<0.05) increasing pattern from 0 to 12 day in aerobic packaging in control as well as fibre enriched low fat kadaknath chicken patties. The psychotropic counts as well as Yeast and Mold count under aerobic packaging were not detected up to 9 day of storage either in control or in fibre enriched low fat kadaknath chicken patties and these were detected on 12 day of storage. The coliform were not detected during the entire period of storage in aerobic packaging. Sensory attributes under storage study did not have any significant (P>0.05) difference between control and fibre enriched low fat kadaknath chicken patties on all storage days of aerobic packaging. The mean scores for all the sensory attributes for both control as well as fibre enriched low fat kadaknath chicken patties decreased gradually with increasing storage period. From the study it was concluded that the fibre enriched low fat kadaknath chicken patties may be considered as health full product which was very well stable and accepted up to 12 day in aerobic packaging under refrigeration.

Pretreatment optimization of tissue metabolomics in colorectal cancer.

To optimize the pretreatment method of colorectal cancer tissue samples for metabolomics research based on solid-phase nuclear magnetic resonance (NMR). The mucosal tissues of colorectal cancer were classified into five groups with a volume of 0.2 cm*0.2 cm*0.2 cm. The pretreatment methods for each group were as follows: I. Preservation with liquid nitrogen alone. Samples were also treated with liquid nitrogen for 10 (II), 20 (III), and 30 min (IV), respectively, immediately after isolation and then transferred to a -80℃ refrigerator; V. Only -80℃ refrigerator storage. No more than 30 minutes should pass between isolation and pretreatment of tumor samples. The tissue sample testing process was carried out on Bruker AVII-600 NMR Spectrometer. NMR signals were collected and analysed using partial least-squares discrimination analysis (PLS-DA) to explore the effects of different pretreatment methods on the metabolic changes of samples. The levels of pelargonic acid, stearic acid, D-Ribose, heptadecanoic acid, pyruvic acid, succinate, sarcosine, glycine, creatine, and L-lactate in the group I (only liquid nitrogen) were significantly lower than the other groups (p<0.05); the content of glycerophosphocholine in the group I (only liquid nitrogen) was lower than that in the other groups (p=0.055). These indicated that the glucose and choline phospholipid metabolism levels of the liquid nitrogen group were significantly lower than those of the other four groups. Liquid nitrogen storage can stop the metabolic process of glucose and choline phospholipid in colorectal cancer tissue samples in vitro, thus maintaining the metabolic state of tissue samples in vivo as much as possible.

Effect of Short-term Storage in a High-humidity Refrigerator on the Quality of Asparagus (&lt;i&gt;Asparagus officinalis&lt;/i&gt; L.) during Storage and Display

アスパラガス（Asparagus officinalis L.）は収穫後の代謝活性が非常に高く，品質を維持するには低温条件で貯蔵することが非常に重要である．本研究では，通常の冷蔵庫では困難な低温かつ高湿度条件を作り出す高湿度冷蔵庫による貯蔵がアスパラガスの若茎の重量，伸長および品質に及ぼす影響を調査した．高湿度冷蔵庫と冷蔵庫でアスパラガスを貯蔵し，経時的にそれらの重量と長さを調査した結果，貯蔵11時間以降，冷蔵庫区より高湿度冷蔵庫区で，若茎の重量と長さの減少量は有意に小さくなり，高湿度冷蔵庫が貯蔵中の若茎の重量減少抑制に有効であることが明らかとなった．次に，各試験区における貯蔵が販売所での陳列・棚持ち期間中の若茎の品質に及ぼす影響を明らかにするため，各冷蔵方式により0～72時間貯蔵した若茎を冷蔵ショーケースで3日間水につけて保管し，保管後の若茎の品質を調査した．その結果，両試験区間に大きな差は認められなかったものの，高湿度冷蔵庫での貯蔵は若茎の急激な重量の増減を抑制したことから，収穫直後の効果的な短期冷蔵技術であると考えられた．また，高湿度区では貯蔵時間が長くなるにつれ，保管後の若茎の重量と伸長量の増加量が小さくなり，糖度が高くなることが判明した．これは低温下での貯蔵が若茎の代謝活性を抑制し，それが若茎の伸長を抑制したことに起因すると考えられた．本研究の結果から，アスパラガスの貯蔵における高湿度冷蔵庫の有用性が示されるとともに，低温下での貯蔵時間が保管後の若茎の品質に影響を与える可能性が示された．この成果はアスパラガスの貯蔵・出荷の体系を考える上での有用な知見となると考えられる．

Silica Nanoparticles with Virus-Mimetic Spikes Enable Efficient siRNA Delivery In Vitro and In Vivo.

Oligonucleotide-based therapy has experienced remarkable development in the past 2 decades, but its broad applications are severely hampered by delivery vectors. Widely used viral vectors and lipid nanovectors are suffering from immune clearance after repeating usage or requiring refrigerated transportation and storage, respectively. In this work, amino-modified virus-mimetic spike silica nanoparticles (NH2-SSNs) were fabricated using a 1-pot surfactant-free approach with controlled spike lengths, which were demonstrated with excellent delivery performance and biosafety in nearly all cell types and mice. It indicated that NH2-SSNs entered cells by spike-dependent cell membrane docking and dynamin-dependent endocytosis. The positively charged spikes with proper length on the surface can facilitate the efficient encapsulation of RNAs, protect the loaded RNAs from degradation, and trigger an early endosome escape during intracellular trafficking, similarly to the cellular internalization mechanism of virions. Regarding the fantastic properties of NH2-SSNs in nucleic acid delivery, it revealed that nanoparticles with solid spikes on the surface would be excellent vehicles for gene therapy, presenting self-evident advantages in storage, transportation, modification, and quality control in large-scale production compared to lipid nanovectors.

Impact of government policies on individual choices of food and potential impact on outcomes and nutrition among vulnerable population during COVID-19 pandemic in low- to middle-income country: Literature review.

Corona Virus Disease 2019 (COVID-19) is a highly infectious disease which has affected almost all countries globally. The disease is caused by the corona virus, transmitted from human to human through droplet infection. The virus was first identified in China in December 2019, and spread worldwide. Despite the virus being highly infectious, there is no cure for coronavirus disease COVID-19. The current global approach in the fight against COVID-19 focuses on travel bans including border closures, restrictions on mass gatherings, and mass vaccination of all adults. However, the travel bans and border closures have shown to negatively affect availability, accessibility, and affordability of basic needs such as food, especially for populations in the low- to middle-income countries. This is so since a good percentage of population in low- to middle-income countries live on hand to mouth, and cannot afford adequate food stock to sustain them for a long period of time. In addition, there is a challenge to afford purchasing storage facilities such as refrigerators for storage of fresh foods. Therefore, the purpose of this narrative literature review is to unveil the impact of government policies on individual choices of food and potential impact on outcomes and nutrition in children, elderly and chronically ill individuals in the COVID-19 pandemic era in low- and middle-income countries from 2020 to 2021.

A comparative quality evaluation study on traditional and modified Wahan Mosdeng (Pork Vorta): An ethnic pork product of Tripura

Wahan Mosdeng is a traditional Tripuri dish, made with pork. This present study was conducted to developed an alternative form of Modified Wahan Mosdeng with a high shelf-life. Modified product was prepared by boiling the uniform 1.5 – 2 cm meat along with fatty tissue cut, in the presence of common salt, Ginger, Turmeric powder, with further addition of 1% vinegar, 2.5% solution of potassium sorbate and 75 µg/g of nisin. Prepared products were stored in refrigeration and frozen temperature separately. Different Physicochemical, microbiological, and sensory parameters were evaluated to get the differential picture between the target and the traditional product. The modified product showed significantly higher cooking yield along with low pH value in both refrigeration and frozen temperature. Collectively alternative form of Wahan Mosdeng recorded superior quality and was also highly acceptable even after 15 days of refrigeration storage and 30 days of frozen storage sample.

A REVIEW ON POST-HARVEST HANDLING PRACTICES OF TOMATO (LYCOPERSICUM ESCULENTUM)

To minimize post-harvest losses, tomato post-harvest handling procedures are crucial. The tomato (Lycopersicum esculentum) is one of the vegetables that is grown and consumed the most all over the world. A healthy, balanced diet includes tomatoes as well. Minerals, vitamins, vital amino acids, and antioxidant qualities are abundant in tomatoes. Tomatoes have a short shelf life and are extremely perishable. Post-harvest management procedures are therefore necessary to satisfy the rising population’s need for food while minimizing losses. Tomato post-harvest losses are primarily brought on by incorrect sorting and grading, in appropriate packaging, improper packaging without removing field heat, lack of storage facilities, and poor transportation. The quality and shelf life of tomato fruit is greatly impacted by handling procedures such as harvesting, precooling after harvest, washing and disinfecting, sorting and grading, packaging, storage, and transportation. Additionally, there are a variety of creative packaging and storage methods, including refrigeration storage, changed atmosphere packaging, and intelligent packaging. This review article mainly focuses on the different ways to reduce post-harvest losses of tomatoes thereby securing food security.

Uji Organoleptik dan Umur Simpan Soyghurt dengan Berbagai Konsentrasi Gula dan Waktu Inkubasi

One of fermented soybean (Glycine max L. Merr) products is soy milk, called as Thew Fu Sui by the community of Bangka Belitung. Soy milk product has unpleasant aroma or “langu” and need to be processed into alternative product such as yogurt. Soy milk yogurt (soyghurt) was made by utilizing the same bacteria in yogurt-making from animal milk including Streptococcus thermophillus and Lactobacillus bulgaricus. Sugar concentration and incubation time were the factors that influenced the fermentation process and product’s taste. This research was conducted to determine the level of people's preference for soyghurt by organoleptic assessment of color, taste, aroma and texture based on variation of sugar concentration and incubation time of soyghurt. Our study found that various additional sugar concentration and incubation time gave difference result in organoleptic test. Soyghurt with 10%, 12.5%, and 15% of sugar addition became more favorable among the participant. The incubation time of 8 hours, 12 hours, and 16 hours equally produced good fermentation results. Storage in refrigerator for 1 days could maintain its flavor, texture, colour and aroma, but changed after 2 days stored.

Alteration of Bioactive Compounds and Antioxidative Properties in Thermal, Ultra-High Pressure and Ultrasound Treated Maoberry (Antidesma Bunius L.) Juice during Refrigerated Storage

Maoberry (Antidesma bunius L.) is a tropical fruit locally referred to as “Mao-Luang” in Thailand. The fruit contains high amounts of ascorbic acid and phenolic compounds with antioxidative potential, which has demonstrated medicinal value in terms of anti-cancer and anti-diabetic effects. In this term, this research purposed to determine the changes of predominant bioactive phytochemicals, antioxidant capacity and microbiological quality of pasteurized (85ºC/1 min), pressurized (500 and 600 MPa/30ºC/30 min), and ultra-sonicated (20 kHz/60% and 80% amplitude/30 min) maoberry juices during storage at 4°C for 30 days. The results displayed that ascorbic acid, phenolic acids (gallic and vanillic acids), anthocyanins (cyanidin 3-o-glucoside and cyanidin 3-rutinoside), flavonoids [(+)-catechin and (˗)-epicatechin), 2,2-diphenyl-1-picryl hydrazyl hydrate (DPPH) radical inhibition and ferric reducing antioxidant power (FRAP) value in pressurized and ultra-sonicated juices displayed higher reduction rate during storage than those in pasteurized juice. Nevertheless, at the final stage of storage, both juices still contained higher levels of antioxidant compounds and properties than in thermally treated juice. All the treated samples were shown to reduce initial microbial load of fresh maoberry juice to a non-detectable amount, while maintaining their quality during prolonged refrigerated storage.

A Study Protocol to Assess the Effects of Storage on Blood Components and Packed Red Blood Cells in Blood Bank

Background: For preservation of Packed Red blood cells (PRBCs), the recommended optimum conditions includes storage at 2-60 C in specialised blood storage refrigerators. PRBCs are required for blood transfusions in some life-saving situations and can be stored for 42 days. But during this storage period, continuous degradation of RBCs occurs and oxygen carrying capacity gets reduced. These changes inadvertently affect the lifespan of stored RBCs. Therefore during this storage period, routine evaluation is recommended. This study aimed to assess the storage effects on Blood Component and internal quality control of packed red cells.&#x0D; Methodology: This Prospective Cohort study includes analysis of 50 Packed Red blood cells bags for RBC count, Haemoglobin and RBC indices. The analysis will be done on Day 1, Day 21 and Day 42 from the date of blood collection. The study will be carried in Jawaharlal Nehru Medical College Blood Centre and Department of Pathology, JNMC, AVBRH, Sawangi Meghe, Wardha. The data collected will be analysed using appropriate statistical tools.&#x0D; Expected Results: Haemoglobin and Red cell indices with the help of cell counter will be analysed. Effects of storage on packed red blood cells will be drawn from the analysis.

Live holding of red king crab (Paralithodes camtschaticus) and snow crab (Chionoecetes opilio) — Effect on microbial growth in processed leg meat during refrigerated storage

The red king crab (RKC, Paralithodes camtschaticus) and snow crab (SC, Chionoecetes opilio) are valuable decapods that can undergo live holding (LH) in onshore facilities before either live export or processing into two cooked-frozen sections (i.e., clusters). This study investigated the effect of the LH time (up to two months without feeding) and temperature (5│10 °C for RKC; 1│5 °C for SC) on the total viable psychrotrophic count (TVCP) and Pseudomonas spp. in the leg meat of cooked RKC and SC. The effect of freezing after cooking was also evaluated. The counts were determined during storage at 4 °C after cooking on the clusters undergoing either immediate refrigeration (IR) or 24-month frozen storage before refrigeration (FBR). In the RKC cooked leg meat, the LH temperature significantly affected the TVCP, with LH at 10 °C leading to higher counts, while the Pseudomonas spp. levels were mainly influenced by the freezing, with lower levels in FBR samples compared to their IR counterparts. In the SC cooked leg meat, the LH conditions did not significantly affect the counts, which were instead significantly lowered by the freezing. From an industrial and commercial standpoint, it can be concluded that LH of RKC at high temperature (10 °C) led to a shorter microbial shelf-life of cooked RKC clusters, with the clusters undergoing FBR showing longer microbial shelf-life than their IR counterparts. By contrast, with the mild cooking regime applied, the LH time and temperature of SC had a lower influence on the microbial shelf-life of cooked SC clusters than that given by the choice of the storage type (IR or FBR) after cooking.

Thymus vulgaris L. Essential Oil: Effect on Fatty Acids and Proteins Oxidation of Little Tuna (Euthynnus alletteratus) Minced during Refrigerated Storage

People are uncomfortable having their food chemically treated to boost its shelf life. Thus, Tunisian Thymus vulgaris Essential Oil (TVEO) were investigated in parallel with its capacity to limit fatty acids and proteins oxidation in tuna (Euthynnus alletteratus) minced during refrigeration storage (4°C). Our results revealed that for tuna preservation, the measured concentrations of PV, TBARS and TVB-N during different storage periods showed a good efficiency of this Essential Oil (EO) (3%) in limiting lipids and proteins oxidation of tuna flesh. Moreover, we observed increase in all batches which was significantly different (P&lt; 0.05) with lots treated with TVEO were the most conserved comparing to the BHT. Overall outcomes suggest that TVEO use for tuna conservation could represent a promising strategy to improve the qualitative characteristics as well as the safety of seafood.