Entire Storage Period Research Articles

Improving the quality properties of soybean oil by using rice bran oil.

This study aims to study the effect of substituting soybean oil (SO) with rice bran oil (RBO) at different levels (25%, 50%, and 75%) on the physical and chemical properties, fatty acid composition, and oxidative stability of SO, also, study the effect of storing SO, RBO, and their blend oils at ambient temperature for a period of 12 months on the content of free fatty acids (% FFA), peroxide value (PV), and thiobarbituric acid (TBA). RBO demonstrated good quality, as evidenced by its initial low values of % FFA, PV, and TBA. Furthermore, RBO was found to be an excellent source of γ-oryzanol, whereas the other oils lacked this compound. Consequently, increasing the proportion of RBO in SO resulted in the least degradation, while pure SO exhibited the highest degree of degradation. Moreover, the blend oils demonstrated an inhibitory effect against oxidation, allowing for a prolonged storage period without the use of industrial antioxidants. Throughout the entire storage period, the % FFA and PV of all tested blend oil samples remained within the limits recommended for human consumption. TBA exhibited a similar trend to PV. However, an incremental increase in TBA values was observed as the storage period of the oils extended. In SO, TBA levels increased from 0.533 mg malonaldehyde/kg oil at the beginning to 1.446 mg malonaldehyde/kg oil after 12 months of storage. In RBO, TBA levels increased from 0.336 mg malonaldehyde/kg oil at the beginning to 0.882 mg malonaldehyde/kg oil after 12 months of storage.

Antioxidant Potential, Phenolic Content, and Nitrate/Nitrite Content in Various Lettuce Varieties

<p>Ten lettuce varieties are analyzed for antioxidant activity, total phenolic, nitrate, and nitrite contents, and the effects of harvest maturity and cold storage in selected varieties are determined. Antioxidant activity and total phenolic content (TPC) are the highest in Red Oak, Red Coral, Red Rapids, and Grand Rapids; intermediate in Green Oak, Green Cos, and Frillice Iceberg; and the lowest in Butterhead, Mini Green Cos, and Head lettuce. Nitrate content is the highest in Red Coral, while the other 9 varieties have comparably lower contents. Nitrite content is inadequate and does not differ with variety. Harvest maturity of 45 days after transplanting (DAT) produced the highest antioxidant activity and TPC, much higher in Red Bowl and Red Butterhead varieties than in Mini Green Cos, Butterhead, Frillice Iceberg, and Green Big Bowl varieties. Storage at 8<sup>o</sup>C for 21 days has no remarkable effects on antioxidant activity, TPC, nitrate, and nitrite contents. Stored Red Bowl lettuce has higher antioxidant activity and TPC than Butter-head and Green Big Bowl varieties. Nitrate content decreases at the end of storage, while nitrite content is below 1 mg/kg FW during the entire storage period, regardless of variety.</p>

Transcriptomic, metabolomic, and physiological analysis of two varieties of Chinese cabbage (Brassica rapa L. ssp. pekinensis) that differ in their storability

The storability of two different varieties of Chinese cabbage was evaluated. Results indicated that' Beijing New No.3′ (N3) exhibited longer storage life and better postharvest quality than' Beijing New No.1′ (N1). Relative to N1, N3 had a lower rate of fresh weight loss and rot development during the latter period of storage (125 days). Ethylene generation and the respiration rate of N3 cabbage were also lower than they were in N1 cabbage over the entire storage period. Chlorophyll (Chl) content was lower in N3 cabbage and the ACS, ACO and ACC enzyme activity were also lower than those in N1 cabbage. Additionally, the relative expression level of COL1, JAZ, MYC2, LOX, ACS, ACO, EBF, EIN3, ERF, and MKK in N1 Chinese cabbage increased, during storage in both varieties, while the relative expression of CDPK, COL1, CAML, and PAL decreased. These results provide valuable information on the storability and quality of Chinese cabbage, especially in relationship to plant hormone levels. The collective data indicate that N3 Chinese cabbage has better storability and postharvest quality than N1.

The shelf life of cooked sausages with reduced salt content

The aim of this study was to compare the microbiological quality of cooked sausages produced with a traditional salt content (2.1%) and reformulated batches with a salt content reduced to 1.7%. The reformulation was tested on two types of comminuted meat products – Špekáčky sausage with a diameter of up to 46 mm or Bologna-type sausages in diameter of 85 mm (Gothaj sausage) or 75 mm (Junior sausage). The total viable count (TVC) increased only slightly during the four-week storage (4 ± 1 °C) of all batches of Špekáčky sausage. Comparing batches 1.7 and 2.1, there is an evident difference in the number of CFU/g, with samples of Špekáčky 1.7 showing numbers of bacteria higher by approximately 1 logarithmic order throughout practically the entire storage period (P = 0.001). The population of lactic acid bacteria (LAB) remained well beneath a value of 5.0 log CFU/g even at the end of the experiment. For Bologna-type sausages, the TVC was either beneath the limit of detection or at its boundary in all samples. LAB were not detected during storage of Bologna-type sausages. The results confirmed that the proportion of salt in cooked sausages can be reduced to 1.7% without negatively affecting the shelf life or safety of the final products.

Supplementation of extender with chamuangone-enriched Garcinia cowa leaf extract improves quality parameters and longevity of cold-stored cat semen

BACKGROUND: Semen preservation by cooling is less expensive, simpler and results in less sperm damage than freezing does. However, spermatozoa can only be preserved for a short period due to the excessive formation of reactive oxygen species (ROS). Although several antioxidants can protect sperms from ROS damage during storage at low temperatures, the use of natural antioxidants derived from plants would be a better alternative. OBJECTIVE: To assess the effects of chamuangone, which can reduce oxidation reactions in cells, on cat semen quality after preservation at 4°C for 15 days. MATERIALS AND METHODS: Epididymal sperm samples were collected before being diluted with tris-citric-fructose-egg yolk (TCFE) extender containing different concentrations of chamuangone (0, 50, 100, 150 and 200 μg/mL) and preserved at 4°C. Semen samples were evaluated before chilling and then every 3 days after chilling for up to 15 days. Each sample was assessed for sperm motility, viability, DNA integrity, plasma membrane integrity and percentage of spermatozoa with intact acrosomes. RESULTS: A significantly higher sperm motility was observed in the group supplemented with 100 μg/mL chamuangone compared to the control after 6 days of storage. However, the chamuangone concentration at 200 μg/mL did not significantly increase the sperm motility when compared to the control for the entire storage period. CONCLUSION: 100 μg/mL chamuangone can improve sperm characteristics during 15 days of preservation at 4°C, keeping sperm alive (49.3 ± 5.2%) and moving (7.1 ± 2.4%). These results can be used for the development of breeding programs using technologically advanced reproductive procedures in domestic and wild cats.

Assessment of the Physicochemical, Antioxidant, Microbial, and Sensory Attributes of Yogurt-Style Products Enriched with Probiotic-Fermented Aronia melanocarpa Berry Juice.

The aim() of this study was to create() various formulations of yogurt enriched with freeze()-dried adjuncts, namely() (i) probiotic Lactobacillus plantarum ATCC 14917 culture(), and (ii) L. plantarum ATCC 14917 fermented black chokeberry juice, along with a commercial() starter culture(). The goal was to enhance() functionality and optimize the nutritional() value() of the products. These new yogurt-style() formulations were subsequently() compared with commercially produced yogurt. All products demonstrated() favorable() physicochemical properties, and the probiotic strain() consistently() maintained viable() levels exceeding 7 log() cfu/g throughout() the entire() storage() period(). The fermented milk produced with the adjunct-free L. plantarum cells, as well as the yogurt produced with the proposed() lactobacilli-fermented chokeberry juice, exhibited the highest lactic acid() production() (1.44 g/100 g yogurt by the end of storage()). Levels of syneresis were observed at lower() values() in yogurt produced with freeze()-dried fermented chokeberry juice. Yogurts prepared() with the lactobacilli-fermented freeze()-dried chokeberry juice displayed elevated total() phenolic content() and antioxidant capacity() (25.74 µg GAE/g and 69.05 µmol TE/100 g, respectively()). Furthermore, sensory tests revealed a distinctive() fruity flavor() in samples incorporating fermented juice. The results demonstrate() that probiotic L. plantarum-fermented chokeberry juice enhances() both the antioxidant capacity() and the viability of beneficial() bacteria() in yogurt while it can be readily() applied and commercialized, especially in the form of a freeze()-dried formulation.

Effect of modified okara insoluble dietary fibre on the quality of yoghurt

The aim of this study was to investigate the potential of adding soya bean dregs insoluble dietary fibre (IDF) modified by jet cavitation combined with cellulase to yoghurt to improve its functional properties (Yoghurt was prepared by adding 10 μL of yoghurt fermenter to 100 mL of milk, fermented to pH 4.5 in a constant temperature incubator at 42 °C, and then stored in a refrigerator at 4 °C after adding IDF separately). The results showed that the modified IDF had a rough structure with high water-holding capacity and sodium cholate adsorption capacity. The addition of modified IDF improved the pH, hardness, and elasticity of the yoghurt. During the entire storage period, the titratable acidity and whey precipitation rate of the modified IDF yoghurt gradually increased, and antioxidant activity gradually decreased, and its titratable acidity, whey precipitation rate, and antioxidant activity had a significant advantage compared with those of the blank group yoghurt. In conclusion, the modified soya bean dregs IDF-added yoghurt prepared by jet cavitation combined with the cellulase method has the potential for sodium cholate adsorption capacity and antioxidant activity, which can confer unique functional properties and improve the pH, texture, and reduce whey precipitation of yoghurt. This study provides a scientific basis for the application of soya bean dregs IDF as a fibre fortifier in yoghurt production and suggests innovative ideas for the design of functional dairy products.

Stability of antimicrobial, antioxidant, and functional properties of pectin‐based film incorporated with Thymus capitatus and Cinnamomum verum essential oils

AbstractBiopolymer‐based films present numerous environmental advantages. The current study aims to investigate the impact of storage time on the antimicrobial, antioxidant, and functional properties of pectin‐based films containing Thymus capitatus (TEO) and Cinnamomum verum (CEO) essential oils (EOs). Films were prepared using the solution casting method; their different properties were evaluated over 1 month at room temperature. Both types of films displayed strong antimicrobial activity against Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), and Salmonella typhimurium (S. typhimurium). Pectin‐based film incorporated with CEO displayed greater antioxidant activity than film incorporated with TEO. The two EOS increased the films' elongation at break and tensile strength. However, their moisture content and thickness decreased. The antibacterial and antioxidant activities of the CEO‐ and TEO‐based films decreased after 4 weeks of storage, while moisture content increased. However, the films' mechanical parameters remained stable during the entire storage period.

Microbiological indicators of quality and safety of hard rennet cheese with linseed content during storage

Food fortification is one of the most important processes for improving the nutritional quality and quantity of food products. Currently, the development of new recipes for dairy products is one of the driving forces of the dairy industry. The purpose of this study was to determine the suitability of the developed hard cheese with flax seeds for storage under the conditions defined by the standard. Microbiological studies were performed according to standard methods, which included the preparation of samples for the study, carrying out tenfold dilutions and sowing them on selective and storage media. Coliform bacteria and lactic acid microorganisms were determined according to DSTU 7357:2013, Salmonella and Listeria bacteria according to DSTU EN 12824:2004 and DSTU ISO 11290-1:2003, respectively. The developed Gouda-type hard cheese with flax seeds showed high microbiological indicators, which characterize its safety and quality, during storage at the temperature regime t... +5 ± 1 °C for 45 days. In particular, according to the amount of coliform bacteria, the product during 45 days of storage had a titer one order of magnitude higher than the maximum allowable limit (0.01 g), and according to the content of Staphylococcus aureus, it had an amount almost 20 times lower than the maximum allowable standard. Pathogenic microorganisms such as L. monocytogenes and Salmonella spp. were not detected in 25 g of the product during the entire storage period. At the end of the storage period, the number of lactic acid bacteria in the cheese was 8.0 ± 0.1 × 108 CFU/g. Therefore, the hard rennet cheese with flax seeds developed by us should show functional properties, both due to the content of flax seeds – a source of omega-3 fatty acids, and due to the vital activity of lactic acid microflora.

Effect of extract of ginger root and liquorice on the microbiological safety of mutton liver pâté

This work aimed to evaluate the effect of ginger root (Zingiber officinale) and liquorice (Glycyrrhiza glabra) extract in liver pates on their microbiological safety, water activity and pH values. Four samples of pates were produced: control (without extracts), variant 1 (addition of 1% liquorice root and 2% ginger root), variant 2 (2% liquorice root, 3% ginger root), variant 3 (3% liquorice root, 4% ginger root). The number of mesophilic aerobic and facultative anaerobic microorganisms, lactobacilli, moulds, yeasts, Staphylococcus aureus, Escherichia coli, and Salmonella on the day of production and after 1, 3, 6 and 12 months of storage were determined. According to the experimental data, the studied microbiological safety indicators were within the permissible standards during the entire period of storage. The lowest microflora growth was observed in variants 1 and 4. With increasing storage time of the samples, a decrease in the value of water activity and an increase in the pH value was observed. Sensory analysis showed a positive trend in pates' taste, texture, and aroma when introducing sheep fat and plant extracts into the recipe. According to the overall sensory analysis score, variant 2 received the highest score (8.5), while the control sample received the lowest score (7.9). The aroma, consistency and juiciness of the pâtés of variant 2 were significantly better (p <0.05). The studies confirmed the prospects of improving the microbiological stability of liver pâté using different combinations of plant extracts.

Effect of modified atmosphere packaging on the quality characteristics and bacterial community succession of super-chilled chicken meat in biopreservation

Microbial contamination and growth play an important role in the spoilage and quality loss of chicken meat. This study, therefore, aims to explore the effect of modified atmosphere packaging (MAP) on the quality characteristics and bacterial community succession of chicken meat in biopreservation under superchilling (−1 °C) conditions. In Group 3 (15% O₂/30% CO₂/55% N₂), the result revealed an enhancement in color, while reducing the total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), pH, total viable count (TVC), Pseudomonas count, lactic acid bacteria (LAB) count, and Enterobacteriaceae count were found in Group 1 (30% CO₂/70% N₂) in comparison to the control (CON) during 30 d of storage. The MAP chicken meat had a more intricate bacterial succession process than the CON, mainly because MAP can prolong the lag phase of microbial growth, thus inhibiting the growth of most microorganisms. During the entire storage period, Pseudomonas was the predominant bacterial flora of CON, while it was significantly inhibited in the MAP groups, with Serratia and Delftia being the most abundant. These results indicate that Group 1 was superior to other groups in preventing bacterial development and maintaining steady quality traits of chicken meat during the 30 d of storage period.

Applications of 1-methylcyclopropene concentrations and timing in relation to sunlight-related core browning in ‘Bartlett’ pears after extending regular-air storage

Core browning (CB) is a crucial physiological disorder that occurs in ‘Bartlett’ pears after excessive storage. Furthermore, environmental factors such as sunlight exposure cause serious related disorders during storage. 1-methylcyclopropene (1-MCP) positively delays the development of disorders, but results in poor eating quality at retail. Therefore, the primary purpose of this study was to evaluate whether sunlight exposure impacts the development of CB in ‘Bartlett’ pears and to develop optimal postharvest 1-MCP strategies for the pear industry to extend the fruit’s lifespan and deliver desirable eating quality to consumers that prefer melting texture. Over the course of a three-year evaluation, sunlight-exposed (SE) pears consistently displayed a higher CB index than the control and non-exposed (NE) pears after 150 d of regular-air (RA) storage at − 1.1 ± 0.5 °C plus 5 d at 20 ± 0.5 °C. The rapid development of CB was facilitated by decreases in ethylene production rate (EPR), peel chlorophyll content (PCC), and titratable acidity associated with increases in malondialdehyde and soluble o-quinones. Applying 0.15 and 0.3 μL L−1 1-MCP after 15 d of harvest completely protected the fruit from CB for up to 150 d of RA storage. However, these treated pears did not ripen. Lowering the 1-MCP concentration to 0.075 μL L−1 and postponing treatment to 60 d after harvest could control the CB index in the 1.53–2.33 range with a normal ripening process. For SE pears, the use of 0.15 μL L−1 1-MCP applied after 60 d of harvest reduced the CB index to 1.63 without impairing ripening capacity. It was difficult for the pear industry to monitor the EPR of 1-MCP-treated pears over the entire storage period. However, when the PCC of the treated pears fell to 0.4–0.5 IAD after 5 d of ripening, these pears could recover their ethylene generation capacity and softening behavior. Overall, the 0.15–0.075 μL L−1 1-MCP applied after 60 d of harvest provided great benefits in delaying CB development, improving storability, and retaining ripening capacity in SE ‘Bartlett’ pears following the prolonged RA storage.

Assessment of the bioactivity, preservation potential and sensory acceptance of a propolis extract applied in a functional fruit-herbal beverage

Functional foods and beverages can be defined as processed products that provide health benefits beyond the basic nutritional needs and reduce the risk of diseases. The design of functional products with improved shelf-life is a new challenge for the food industry. Therefore, this research aimed to: design a functional fruit-herbal beverage; compare the preservation effect of two preservatives (propolis extract and potassium sorbate) added in the beverages; evaluate the sensory characteristics of the newly designed beverages; observe the physico-chemical and microbiological changes during storage at 4℃ for 42 days. The results demonstrated that the addition of propolis extract (0.02%) in the beverage, increased the total polyphenols, total flavonoids and antioxidant activity, compared to the control beverage and the beverage containing potassium sorbate (0.05%). The results from microbiological analyses showed that potassium sorbate and propolis extract effectively inhibited the microbial growth in the treated beverages. However, the propolis extract in a lower concentration (0.02%) was as effective as potassium sorbate in a higher concentration (0.05%) during the entire storage period. Consequently, in addition to being a functional ingredient and a food enhancer, propolis is a prospective natural preservative, which can improve the shelf-life of the food products and beverages.

Physicochemical and bioactive constituents, microbial counts, and color components of spray-dried Syzygium cumini L. pulp powder stored in different packaging materials under two controlled environmental conditions.

Currently, the demand for functional food items that impart health benefits has been rising. Blackberry (Syzygium cumini L.) fruit has high anthocyanin content and other functional attributes. However, this seasonal fruit is highly perishable, and a large proportion of it goes unharvested and wasted worldwide. Spray drying of the fruit pulp can impart improved shelf life, ensuring long-term availability for consumers to exploit its health benefits. The storage quality varies according to the type of packaging material and the storage environment. Therefore, in this study, the shelf life span of the spray-dried Syzygium cumini L. pulp powder (SSCPP) was investigated during 6 months of storage under three types of packaging materials (i.e., polystyrene, metalized polyester, and 4-ply laminates) in a low-temperature environmental (LTE) and at ambient environmental conditions. The physicochemical stability of bioactive principles (TPC and TAC), microbial counts, and color components were analyzed at 0, 2, 4, and 6 months of storage. There was a significant gradual loss of dispersibility and solubility with an increase in flowability, bulk density, and wettability during the entire storage period for all three packaging materials. The TSS, pH, TPC, TAC, and microbial counts decreased in the SSCPP both at ambient and LTE conditions during the study. Among all the packaging materials, the 4-ply laminate was found to be the most appropriate and safe for storage of spray-dried SCPP at LTE conditions.

Evaluation of the storage longevity, postharvest quality, and sugar metabolism-related gene expression in two lines (N1 and N3) of Chinese cabbage during long-term storage

The quality and taste of ‘Beijing New 3′ (N3) and Beijing New 1′ (N1) Chinese cabbage was assessed using physiological indicators monitored during storage and by transcriptome profiling conducted at 0, 25, and 100 d of storage. Results indicated that N3 had better storage longevity and postharvest quality, relative to N1. Electrolyte leakage values in N3 increased at a slower rate than they did in N1 cabbage during the latter stages of storage (125 days), while ethylene levels and respiratory rates were also lower in N3 cabbage than in N1 cabbage during the entire period of storage. The N3 variety had a higher sugar content (mainly glucose and fructose) during storage than the N1 variety. The expression level of genes involved in sugar metabolism, such as hexokinase (HK), sucrose synthase (SUS), phosphofructokinase (PFK), fructose bisphosphate aldolase (FBA), PCKA (Phosphoenolpyruvate carboxykinase), ALDO (aldose), GAPDH (glyceraldehyde phosphate dehydrogenase), and ENO (Enolase) were higher in N3 than in N1, while the expression level of GPI (Glycosylphosphatidylinositol) and PGM (Phosphoglucomutase) was lower. These results provide valuable information on the quality and taste of Chinese cabbage, especially in relation to sugar metabolism, and indicated that N3 had better postharvest storage properties than N1.

Quality Evaluation of Mackerel Fillets Stored under Different Conditions by Hyperspectral Imaging Analysis.

This study was designed to compare the quality changes in mackerel fillets stored under different conditions by using hyperspectral imaging (HSI) techniques. Fillets packaged in vacuum were stored for six days under five different conditions: refrigerated at 4°C (R group); iced at 5±3°C (I group); kept at an ambient of 17±2°C (A group); frozen at -18°C for 24 h and thawed in a refrigerator at 4°C for 5 h on the sampling day (FTR group); FTR thawed in tap water instead of thawing in a refrigerator (FTW group). The FTR group had the lowest total bacterial count, drip loss, 2-thiobarbituric acid reactive substances, volatile basic nitrogen, and texture profile analysis values among groups during the entire storage period (p<0.05). Scanning electron microscopy revealed that the FTR group had less damage, while the other groups had shrunken muscle tissues. HSI integrated with the partial least squares model yielded reliable and efficient results, with high R2cv values, for several quality parameters of the mackerel fillets. Overall, the FTR group, involving freezing and thawing in a refrigerator, appears to be the most favorable option for maintaining the quality of mackerel fillets, which could be practically implemented in the industry. HSI is a suitable and effective technique for determining the quality of mackerel fillets stored under different conditions.

Hydroxypropyl Methylcellulose and Gum Arabic Composite Edible Coatings Amended with Geraniol to Control Postharvest Brown Rot and Maintain Quality of Cold-Stored Plums.

In this study, the effect of hydroxypropyl methylcellulose (HPMC) and gum Arabic (GA) edible coatings amended with 0.2% geraniol (GE) were evaluated for the control of brown rot, caused by Monilinia fructicola, on artificially inoculated plums (Prunus salicina Lindl., cv. Angeleno) stored for 5 weeks at 1 °C. Brown rot is the most important pre- and postharvest fungal disease of stone fruits, causing severe economic losses worldwide. Geraniol is an important constituent of many essential oils that can be obtained as a byproduct from different industrial procedures, such as those of the juice industry. Fruit postharvest quality was also evaluated after 5 and 8 weeks of storage at 1 °C, followed by 3 days at 7 °C plus 5 days at 20 °C, simulating packinghouse, transport, and retail shelf-life conditions, respectively. HPMC coatings containing 0.2% GE reduced the incidence and severity of brown rot by 37.5 and 64.8%, respectively, compared to uncoated fruit after 5 weeks of storage at 1 °C. HPMC-coated plums, with and without GE, showed the highest level of firmness, the lowest change in external peel color parameters (L*, a*, b*, C*, hue), and the lowest flesh bleeding compared to uncoated control and GA-coated samples throughout the entire storage period, which correlated with a higher gas barrier of these coatings without negatively affecting sensory quality. Furthermore, the HPMC-0.2% GE coating provided the highest gloss to coated plums, showing the potential of this coating as a safe and environmentally friendly alternative to conventional fungicides and waxes for brown rot control and quality maintenance of cold-stored plums.

Comparison of postharvest quality of Aralia elata shoot according to packaging methods

In this study, we aimed to evaluate the quality of Aralia elata shoots according to different packaging methods during storage at 2°C. The highest level of dehydration and wilting incidences were observed in polypropylene containers with polyvinyl chloride wrap (PP+PVC), and these levels continually increased during the entire storage period, compared to other packaging methods. The overall marketability of A. elata shoot packaged in polyethylene terephthalate container (PET) and PP with the mineral-coted functional warp (PP+F) constantly declined during storage with a similar level of 38.6 and 36.0% at 15 days in storage, respectively. PP with PET cover packaging (PP+PET) showed the lowest decay and wilting rates during the entire storage, and the wilting score at 10th day was 51.9, 58.0, 51.8% suppressed, as compared to PET, PP+PVC, and PP+F, respectively. Consequently PP+PET packaging effectively decreased the deterioration of A. elata and maintained marketability for 10 days of storage at 2°C.

The investigation of flocculation and deposition of heavy components in the crude oil tank based on experiment and molecular simulation

With the implementation of the “3060” carbon neutrality policy, the cancellation of external insulation has led to the increasingly serious deposition of heavy components in petroleum storage tanks. However, there are few studies on the flocculation and deposition behavior of industrial complex crude oil systems during the entire storage period in tanks. This study used an equivalent crude oil tank system to systematically investigate the flocculation and deposition behavior of industrial crude oil systems during storage. Static settling experiments were conducted for the entire storage period (32 days) to measure changes in oil parameters such as density, wax appearance temperature (WAT), gel point, and particle size at different heights in the tank. In addition, a full-component molecular system for crude oil was constructed, and molecular dynamics (MD) simulation was used to reveal the flocculation and aggregation mechanisms of heavy components in crude oil systems for the first time. The result showed that the maximum density difference between the upper and lower of the test tank is 14 kg/m3 and the marked stable time of sedimentation is 163 h. The maximum increment of the WAT appears at the bottom of the tank with the value increasing from 38.17 °C to 45.75 °C. The microscopic observations are consistent with the changes in macroscopic parameters. The wax is very prone to aggregation and wax crystals show a face-to-face sticking state. As for asphaltenes, the degree of aggregation is weaker than that of wax molecules, and the aggregation state mainly shows two manners: T-shape sticking and face-to-face sticking. This study can provide the theoretical basis for tackling the tank bottom sediment.

Microbial Inhibition by UV Radiation Combined with Nisin and Shelf-Life Extension of Tangerine Juice during Refrigerated Storage.

This study evaluated the efficiency of UV radiation doses (4.68-149.76 J/cm2) and nisin (50-200 ppm) and their combination in comparison with thermal pasteurization on the microbial inhibition kinetics and physicochemical properties of tangerine juice. It was noted that UV-149.76 J/cm2 and nisin (NS) at 200 ppm in conjunction exhibited the highest log reduction in spoilage and pathogenic microbes including Escherichia coli, Lactiplantibacillus plantarum, and Saccharomyces cerevisiae, yeast and molds, and total plate count in tangerine juice. Additionally, the first-order kinetic model provides a better fit for spoilage and pathogenic strains compared with the zero-order model (higher coefficient of determination, R2), particularly for E. coli. UV and NS showed insignificant effects (p > 0.05) on pH, TSS, and TA values compared with pasteurization. However, there were notable differences observed in color analysis, total phenolic compound, total flavonoid content, vitamin C, carotenoid content, and antioxidant activity using DPPH and FRAP assays. The optimized UV + NS samples were subjected to refrigerated storage for 21 days. The results revealed that during the entire storage period, the pH values and the TSS values slightly decreased, and the TA values increased in the treated samples. The UV + NS treatment insignificantly impacted the color properties. The total phenolic, total flavonoid, and carotenoid contents, and vitamin C decreased over time for all sample treatments, whereas the antioxidant properties exhibited varying outcomes, compared with an untreated control and pasteurization. Therefore, UV radiation and nisin (UV-149.76 J/cm2 + NS-200 ppm) in combination could serve as a viable alternative to traditional heat pasteurization of fruit juice during cold storage.