Total Volatile Production Research Articles

Effects of CO2 on the physicochemical, microbial, and sensory properties of pork patties packaged under optimized O2 levels

The storage quality characteristics of fresh pork patties were investigated under 80% O2 modified atmosphere packaging (MAP80:20 = 80% O2/20% CO2) and 40% O2 MAP with various CO2 levels (MAP40:20 = 40% O2/20% CO2/40% N2; MAP40:40 = 40% O2/40% CO2/20% N2; MAP40:60 = 40% O2/60% CO2). Packaged patties were stored for 16 days at 4 °C to monitor their physicochemical (pH, instrumental color, oxidative stability, and fatty acid profile), microbial, and sensorial changes. Results suggested that decreasing O2 levels from 80% to 40% significantly inhibited the lipid oxidation of patties but led to a lower (P < 0.05) color stability. Elevating CO2 levels from 20% to 60% in combination with 40% O2 significantly suppressed bacterial growth and total volatile basic nitrogen production, and thus rendered patties with a better sensory quality and a similar meat color to 80% O2. However, increased CO2 levels promoted lipid oxidation through reducing the antioxidant capacity of patties, which was attributed to a CO2-induced reduction in superoxide dismutase and glutathione peroxidase activities during storage rather than a pH reduction or changes in fatty acid composition. Overall, 40% O2/40% CO2/20% N2 is a realistic alternative for pork patties to improve meat quality and extend the shelf-life to over 16 days.

Photodynamic inactivation of spoilers Pseudomonas lundensis and Brochothrix thermosphacta by food-grade curcumin and its application on ground beef

This study evaluated the bactericidal effects of curcumin-mediated photodynamic inactivation (PDI) combined with citric acid on meat spoilage bacteria, and their preservative effects of refrigerated beef. After treatment of PDI (60 μM curcumin and 33.01 J/cm2) combined with 0.5 mg/mL citric acid, the populations of Pseudomonas lundensis and Brochothrix thermosphacta in PBS solution were reduced by 3.07 and 6.14 log CFU/mL, respectively, compared to 0.31 and 1.39 log CFU/mL for PDI. Combined treatment enhanced reactive oxygen species (ROS) activity in the two strains, and damaged their cell morphology, especially B. thermosphacta. With increasing curcumin concentration, the growth rate of spoilage bacteria was significantly inhibited (P < 0.05), and the changes of dominant spoilage species in bacterial community were retarded in aerobic-packaged and vacuum-packaged ground beef at 4 °C. Compared to the control, trichloroacetic acid-soluble peptide and total volatile basic nitrogen production were greatly restrained, and changes in pH values and brown color were apparently reduced for the combined treatment, which could extend the shelf life by 2 days. These results suggested the synergistic potency of PDI combined with citric acid against spoilage bacteria in meat products.Industrial relevance: The proliferation and spread of some psychrotrophs are major causes of quality deterioration and cross-contamination in fresh meat during cold chain. This study revealed that photosensitized curcumin combined with citric acid significantly decreased the survival of two psychrotrophic spoilage bacteria and extended the shelf-life of ground beef. Thus, curcumin-based PDI provides a new insight for the development of efficient and economic preservation in the meat processing industry.

Volatile products generated from reactions between ozone and human skin lipids: A modelling estimation

Human surfaces have a significant influence on indoor air due to their interaction with ozone. The oxidation products of unsaturated fatty acids and triglycerides have not been systematically studied. In this investigation, the kinetic model (KM-SUB-Skin-Clothing) was used to simulate the interaction of ozone and human skin lipids, including squalene, unsaturated fatty acids and triglycerides for typical residential rooms. Based on a theoretical reaction mechanism, 21 volatile products and their concentrations were determined. The results indicate that acetone was the most abundant anticipated product, followed by 6-MHO, geranyl acetone, 4-OPA, and heptanal. When the window was closed, the sum of concentration of volatile products increased sharply and became higher than ozone over 1 h. The concentration of carbonyls was 3–6 ppb (∼2–8 times) higher than dicarbonyls. Total volatile products generated from squalene was 3–5 ppb (∼3–5 times) higher than those generated from unsaturated fatty acids and triglycerides.

Evaluation of Dry-Heat Cookery Method on Volatile Flavor Compound Development and Consumer Evaluation of Six Beef Muscles

The objective of this study was to determine the influence of dry-heat cookery on beef flavor development of multiple beef muscles. Beef strip loins, top sirloin butts, paired tenderloins, paired shoulder clods, and chuck rolls were collected from USDA Low Choice carcasses (Small00–Small100 marbling; N = 20). Subprimals were wet aged in the absence of light for 21 d at 0°C to 4°C. Subprimals were fabricated into 2.54-cm-thick steaks representative of the following muscles: Gluteus medius, Infraspinatus, Longissimus lumborum, Psoas major, Serratus ventralis, and Triceps brachii and randomly assigned to one of 4 dry-heat cookery methods: charbroiler grill (CHAR), clamshell grill (CLAM), convection oven (OVEN), and salamander broiler (SALA). Steaks were cooked to a medium degree of doneness (71°C) on the randomly assigned cooking method. Untrained consumer panelists (N = 300) evaluated each sample for flavor, tenderness, juiciness, and overall liking. No interactions were observed between cooking method and muscle (P ≥ 0.344) for any palatability traits evaluated. Consumers preferred CHAR steaks (P &amp;lt; 0.05) over CLAM steaks for flavor, tenderness, juiciness, and overall liking. Additionally, CLAM steaks were rated lower (P &amp;lt; 0.05) than all other methods for tenderness and juiciness. OVEN and SALA steaks were rated higher (P &amp;lt; 0.05) than CLAM steaks by consumers for tenderness and juiciness but were similar (P &amp;gt; 0.05) to CLAM steaks for overall liking. CHAR steaks produced a greater concentration of Maillard compounds compared with the other cooking methods. Steaks cooked using OVEN and SALA (P &amp;lt; 0.05) produced more lipid oxidation products. Additionally, CHAR steaks produced the greatest (P &amp;lt; 0.05) total volatile production compared with all other treatments, which may be a result of the combination of Maillard reaction products and the lipid degradation products.

AprD is important for extracellular proteolytic activity, physicochemical properties and spoilage potential in meat-borne Pseudomonas fragi

Pseudomonas fragi is a common spoilage agent of aerobically stored chilled meat. Its extracellular protease contributes to the spoilage of meat. AprD is considered an important component involved in the secretion of an alkaline extracellular protease in Pseudomonas. Thus, it is very possible that aprD plays an important role in spoilage regulation in P. fragi. The objective of the present study was to investigate the effects of aprD on bacterial proteolytic activity, biological properties, and in situ spoilage potential, as well as the mode of action of the protease AprA in spoiled meat. The results showed that aprD is important for surface-associated behaviors, as an ΔaprD mutant altered autoaggregation, swimming motility, and biofilm formation. aprD also contributes to the spoilage activities of P. fragi by affecting extracellular protease activity, total volatile basic nitrogen production, pH and the sensory traits of meat samples. These results highlight the presence of aprD-mediated regulation profiles in P. fragi and may provide new perspectives on chilled meat preservation.

97 Effects of alkalization treatment on chemical composition and in vitro ruminal fermentation of anaerobically stored rice stover

Abstract The objective of this trial was to evaluate the effects of urea and calcium hydroxide on the chemical composition and in vitro ruminal fermentation of rice stover. Rice stover was stored in polyethylene bags (35 × 25 cm, 350g per bag) with: (i) no additive (CON); (ii) 4% calcium hydroxide (CA, dry matter (DM) basis); (iii) 2.5% urea and 4% calcium hydroxide (UCA, DM basis); and (iv) 9% corn steep liquor and 2.5% urea and 4% calcium hydroxide (CUCA, DM basis). Dry matter were kept at the same level at 55% for all treatments. Totally, 36 bags (4 treatments × 3 store periods × 3 repeats) were prepared and stored at ambient temperature (25 ± 3 °C). The chemical composition was measured at day 7, 10 and 15 after storage. And the in vitro ruminal fermentation was tested in vitro at d 15. Date was subjected to two-way analysis of variance (ANOVA) with the fixed effects of treatments, times and treatments × times by using SPSS 24.0. All alkali treatments reduced neutral detergent fiber (NDF) and acid detergent fiber (ADF) content (P &amp;lt; 0.05), and increased the in vitro DM digestibility (IVDMD) of the rice stover compared with the CON. The in vitro NDF degradability (IVNDFD) and ADF degradability (IVADFD) were increased in UCA and CUCA rice stover (P &amp;lt; 0.05) compared to others. The highest acetic acid (AA), propionic acid (PA), butyric acid (BA), total volatile acids (TVFA) concentrations and 48-h cumulative gas production were observed in CUCA rice stover (P &amp;lt; 0.05). With the delay of storage time, dry matter (DM) and crude protein (CP) were decreased in CA and CUCA groups (P &amp;lt; 0.05). Results in this study suggested that 9% corn steep liquor and 2.5% urea and 4% calcium hydroxide might be an effective treatment combination.

Raspberry ketone supplements provided to immature male Queensland fruit fly, Bactrocera tryoni (Froggatt), increase the amount of volatiles in rectal glands

Raspberry ketone (RK) supplements provided together with sugar and yeast hydrolysate accelerate sexual maturation and increase mating success of Queensland fruit fly (‘Qfly’) males. However, the mechanisms underlying this enhanced mating ability are currently unknown. Volatiles are an important element of Qfly sexual calling and courtship and so changes in volatiles quantity or quality may be involved, and the present study investigated this possibility. Flies were fed a diet of sugar only (S) or yeast hydrolysate mixed with sugar (YH + S) (1:3) that contained 0% RK (control) and 5% RK (treated) for 2 days after emergence. Volatile compounds were extracted from rectal glands when flies were 6, 8, 10, 20, and 30 days old. Males fed on RK exhibited a significant increase in total volatile production in rectal glands compared to RK-unfed males (control). Males fed on RK with YH + S produced significantly higher amount of volatiles than males fed on RK with sugar only. Males fed on YH + S diet produced more volatiles in the presence of RK compared to males fed on YH + S diet only. Two compounds, N-(3-methylbutyl)acetamide and N-(3-methylbutyl)propanamide were dominant in endogenously produced rectal gland volatiles comprising ca. more than 90% of the total amount in both RK-fed and control males. Considering exogenous and endogenous compounds together, unaltered RK was dominant along with these two endogenous compounds in RK-fed males in rectal gland until 30 days of age in both diet groups.

Supplementation of diets with tannins from Chestnut wood or an extract from Stevia rebaudiana Bertoni and effects on in vitro rumen fermentation, protozoa count and methane production.

The aim of the trial was to evaluate the effect of dietary additions of Stevia rebaudiana Bertoni extract (SB) and Chestnut wood tannin (CWT) on the in vitro rumen fermentability, protozoal population and methane yield. Both plant products were tested at 3 different levels of inclusion (0.75, 1.50 and 3.00% of incubated dry matter, DM) in a total mixed ration (TMR) for ruminants by using rumen batch culture systems and a rumen inoculum collected from sheep. Total volatile fatty acid concentration, their proportions and gas production were not modified by the plant extracts inclusion, except a significant linear increment of gas production at 24hr for SB (p=.049). Ammonia concentration decreased (p<.05) of about 17% when 1.50 or 3.00% of CWT were included into TMR. Rumen protozoa population was depressed by the SB inclusion (p=.002) with a maximum reduction of 40% at the highest SB dosage, whereas CWT negatively affected total protozoa counts (-19%) only at the dose of 3.00%. In vitro DM and NDF degradability were not affected by the supplementation of SB and CWT, as well as the methane yield. Thus, the addition of SB and CWT decreases the in vitro protozoa population of the rumen with different intensity and without effects on fermentation parameters, apart from a reduction of nitrogen degradability caused by CWT. Despite the effect on protozoa, no decreasing effect on methane production was detected.

Effect of Chinese Rice Wine on the Endogenous Protease Activity, Myofibrillar Degradation, and Quality Characteristics in Topmouth Culter (Culter alburnus)

ABSTRACT The aim of this study was to investigate the influence of rice wine (Jinbiao, Yinbiao, Wunianchen, Nv’erhong) on the endogenous protease activity, myofibrillar degradation, and quality characteristics of topmouth culter (Culter alburnus). Rice wine had a pH of 4.3 and calcium ions ranging from 89.30 to 123.70 μg/mL. Nv’erhong rice wine had the highest total phenolic content of 583.38 μg gallic acid equivalent (GAE)/mL, while Wunianchen rice wine (WNC) showed the strongest total antioxidant capacity of 87.29 U/mL. WNC presented the optimum inhibitory effect on endogenous proteases of calpain and cathepsin B, D, and L, delaying the degradation of myosin heavy chain and α-actinin, which are important to muscle softening. The quality characteristic evaluation indicated that the addition of rice wine could maintain the hardness and chewiness, increase the springiness of the fish fillet, as well as inhibit the total volatile basic nitrogen production. These results suggest that rice wine had effects of inhibiting endogenous proteases, delaying myofibrillar degradation, and maintaining the sensory quality of topmouth culter.

Propionic acid bacteria enhance ruminal feed degradation and reduce methane production in vitro

ABSTRACT Thirty-one strains of propionic acid bacteria were screened for their effects on methane production and volatile fatty acid concentrations using in vitro assays of rumen fluid from Norwegian dairy cows and a grass silage–concentrate mixture as substrate. Nine of 31 strains were further analysed for effects on substrate degradation. Propionic acid bacteria led to reductions of up to 20% in methane production. Seven strains stimulated volatile fatty acid production, and in their presence in vitro substrate degradation tended to increase (P < .10). Most consistent results were found with Propionibacterium thoenii T159, which reduced methane production by 20% and caused 8% and 21% overall increases in substrate degradation and total volatile acid production, respectively (P < .05). Concomitant beneficial effects of a reduction in methane emissions and an increase in feed degradation suggest that this strain may be a promising tool for improving the productive performance of dairy cows.

Effects of inclusion of purple prairie clover (Dalea purpurea Vent.) with native cool-season grasses on in vitro fermentation and in situ digestibility of mixed forages

BackgroundIncorporation of legume species into native North American pastures is considered an effective method to increase native pasture productivity and improve the nutritive value of forage. This study evaluated the effects of inclusion of purple prairie clover (PPC, Dalea purpurea Vent.), a native legume forage, with native cool-season grasses on the in vitro fermentation and in situ digestibility of mixed forages.MethodsWhole plant PPC and mixtures of cool-season grasses were harvested when the PPC reached the vegetative (VEG), full flower (FL) and seedpod (SP) stages, and were combined in ratios (DM basis) of 0:100, 25:75, 50:50, 75:25 and 100:0 at each maturity. In vitro ruminal incubations using these mixtures were conducted for 48 h to determine gas production (GP), in vitro DM disappearance (IVDMD), total volatile fatty acids (VFA) and ammonia-N production. Mixtures of forages harvested when the PPC reached the FL stage and 50:50 mixture of forages harvested at VEG, FL and SP stages were incubated in the rumen of three heifers for 0, 2, 6, 12, 24, 48, 72 and 96 h to determine in situ degradabilities of DM, neutral detergent fibre (aNDF) and crude protein (CP).ResultsContents of aNDF and ADF increased (P < 0.01), while CP decreased (P < 0.001) as PPC matured. Concentrations of extractable condensed tannins in PPC ranked as FL > VEG > SP (P < 0.05). Regardless of PPC proportions in the mixture, GP decreased (P < 0.05) with increasing PPC maturity. Increasing PPC proportions linearly increased (P < 0.001) GP, IVDMD and total VFA at VEG, but linearly decreased (P < 0.001) them at SP. Irrespective of PPC maturity, ammonia-N production linearly increased (P < 0.01) with increasing proportions of PPC and the concentration was higher (P < 0.05) at VEG than at FL and SP stages. Increasing proportion of PPC at either maturity linearly increased (P < 0.001) molar percentage of acetate (A) and branched-chain VFA, but linearly decreased (P < 0.001) molar percentage of propionate (P), resulting in a linearly increase (P < 0.001) in the A:P ratio. Increasing FL PPC in the mixture linearly and quadratically (P < 0.01) increased a (soluble fraction), but linearly and quadratically decreased (P < 0.01) b (potentially degradable fraction) for DM and aNDF, resulting in linear (P < 0.05) and quadratic (P < 0.01) increases in DM and aNDF maximum potential degradabilities (a + b). Effective degradabilities of DM and aNDF were also linearly and quadratically increased (P < 0.05), and CP was quadratically increased (P < 0.05) with increasing FL PPC, with the greatest effective degradability being observed with ratios between 50:50 and 75:25. Ruminal maximum potential degradabilities of DM and aNDF decreased (P < 0.001) as the forage matured. Effective degradability of DM ranked as VEG > FL > SP (P < 0.001), whereas the effective degradability of aNDF was similar between VEG and FL and both were greater (P < 0.01) than SP.ConclusionsInclusion of vegetative PPC in a mixed forage diet resulted in the greatest digestibility and incorporation of PPC before seedpod stage with native grasses had a positive effect on ruminal fermentation. Effects of PPC on ruminal digestion depend on both the stage of maturity and its proportion in mixed legume-grass pastures. Pastures containing 50% of PPC in full flower stage would likely provide the greatest quality diet to grazing ruminants subject to potential animal selectivity.

Effects of Microalgae Species on In Vitro Rumen Fermentation Pattern and Methane Production

Abstract This experiment was conducted to establish the effects of two types of microalgae [Chlorella vulgaris (AI), C. variabilis (AII) and their combination (AI+AII)] with two substrates (wheat and corn silages) on rumen fermentation, gas and methane production. To each substrate, one of 3 algae treatment was supplemented at 0% and 25% of the total incubated dry matter. A series of 5 measurement points (3, 6, 12, 24 and 48 h) were completed and the gas production was monitored. The proximate and mineral composition of microalgae and substrates were examined. At 48 h incubation rumen fermentation variables and CH4 production were also assessed. When compared with wheat silage, corn silage caused an increase in gas production (P&lt;0.05). Ruminal gas production decreased in the algae groups when compared to the controls (0% algae, wheat and corn silages, P&lt;0.05). Among algae, C. vulgaris had the strongest effect, decreasing gas production by 34%. Among algae, the total volatile fatty acids (VFA) and CH4 production were found to be lower in C. variabilis (P&lt;0.001). Ammonia-N increased with the algae inclusion (P&lt;0.05). But, the ruminal gas production, pH, acetate, the total VFA, CH4 and rumen fermentation efficiency were not affected by the substrate and algae interaction (P&gt;0.05). The propionate was the highest (P&lt;0.05) for corn silage when incubated with C. vulgaris. Ruminal butyrate was the lowest for the wheat silage when incubated with the mixture of algae (P&lt;0.05). The NH3-N was the highest in corn silage when incubated with all algae types (P&lt;0.05). Careful selection and combination of substrate and algae may positively manipulate rumen fermentation and may inhibit CH4 production. Further research is needed to validate these results in vivo.

Characteristics of dehydration during rice husk pyrolysis and catalytic mechanism of dehydration reaction with NiO/γ-Al2O3 as catalyst

Dehydration is the first chemical reaction in biomass pyrolysis. The process of dehydration has great influence on the subsequent chemical reactions and product distribution. There is little research on dehydration characteristics of real biomass during pyrolysis. Therefore, in this study the dehydration characteristics were investigated using rice husk as the biomass representative in the pyrolysis experiments. On this basis, NiO/γ-Al2O3, was used as the catalyst for rice husk pyrolysis to study its catalytic mechanism for the dehydration reaction of biomass. Results of the pyrolysis experiments indicated that dehydration reaction mainly occurred in the temperature range of 250–350 °C, in which the mass of water produced was around 5.92% of the dry raw material. Through comparing the dehydration curve with thermogravimetric (TG) curve of rice husk, it was found that the dehydration was one of the primary reactions during the pyrolysis, and the accumulated water produced attained to 33.82 wt% of total volatile products of the pyrolysis at 400 °C. When catalyst NiO/γ-Al2O3 was used with NiO loading in the range of 5–20%, the production of water increased by 0.88–1.04 times at 350 °C under the pyrolysis condition in this study. The results of catalytic pyrolysis showed that γ-Al2O3 was the major active component for catalyzing the dehydration reactions. Through characterization of the catalysts by temperature programmed desorption of ammonia (NH3-TPD), X-ray diffraction (XRD), and scanning electron microscopy (SEM), it was found that the weak acid sites on γ-Al2O3 surface played the most important role in the catalytic dehydration reactions.

A Study on VS Removal Efficiency and Methane Emission in Combined Anaerobic Digestion of Livestock Manure and Food Waste

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane (CH4) from the anaerobic digestion process; and third, to promote CH4 production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), CH4 production, and biodegradability.

Enhancing the bioproduction of value-added aroma compounds via solid-state fermentation of sugarcane bagasse and sugar beet molasses: Operational strategies and scaling-up of the process

Bioproduction of generally recognized as safe (GRAS) products starting with low-cost raw materials has become significant in the biorefinery concept. Thus, the solid-state fermentation (SSF) of agro-industrial residues using GRAS strains appears as alternative to obtain aroma compounds. Here, the SSF of the mixture sugarcane bagasse/sugar beet molasses was used for producing a mixture of value-added fruit-like compounds. The study aimed to enhance the production and ester selectivity evaluating three operational strategies at three scales (0.5, 4.5 and 22 L) using non-sterilized residues. While the average total volatile production was 120 mgVol per gram of dry substrate (g−1ITS), fed-batch operation promoted the highest increases in the ester content up to 57 mgEst g−1ITS, an 88 and 59% more than in the static-batch and intermittent mixing modes respectively. Alternative operational strategies have compensated the scale-up adverse effects in the bioproduction, moving towards a sustainable large-scale application in a circular economy scheme.

Identification and expression patterns of alcohol dehydrogenase genes involving in ester volatile biosynthesis in pear fruit

AbstractAlcohol dehydrogenase (ADH) catalyzes the interconversion of aldehydes and their corresponding alcohols, and is a key enzyme in volatile ester biosynthesis. However, little is known regarding ADH and ADH encoding genes (ADHs) in pear. We identified 8 ADHs in the pear's genome (PbrADHs) by multiple sequences alignment. The PbrADHs were highly homologous in their coding regions, while were diversiform in structure. 9 introns were predicted in PbrADH3–PbrADH8, while 8 introns, generated through exon fusion and intron loss, were predicted in PbrADH1 and PbrADH2. To study the genetic regulation underlying aroma biogenesis in pear fruit, we determined the PbrADH transcripts, ADH activities and volatile contents of fruits during ripening stage for Nanguoli and Dangshansuli, two cultivars having different aroma characteristics. ADH activity was strongly associated with the transcription of ADH6 in the two cultivars during fruit ripening stage. The higher ester content paralleling to a higher ADH activity was detected in Nanguoli than in Dangshansuli, so it is induced that the lower ester content in Dangshansuli fruit may be the result of weak ADH activity. The present study revealed that total ADH activity and volatile ester production correlated with increased PbrADH6 transcript levels. PbrADH6 may contribute to ADH activity catalyzing aldehyde reduction and ester formation in pear fruit.

Pyrolysis of Huadian Oil Shale in an Infrared Heating Reactor

Pyrolysis of Huadian oil shale was investigated in a newly designed shallow fixed bed reactor mounted with infrared heating to clarify the pyrolysis behavior at different heating rates and pyrolysis temperatures under minimized secondary reactions to volatiles in an oil shale bed. The maximum shale oil recovery was obtained under the proper conditions of a heating rate of 0.5 °C/s, a pyrolysis temperature of about 550 °C, a reduced reaction pressure (0.6 atm in this work), and for a single-layer oil shale bed. The highest shale oil yield under such conditions was close to 100% of the Fischer Assay oil yield (11.10 wt % of dry basis). For the adopted infrared-heating reactor, increasing the heating rate decreased the shale oil yield but increased the gas production. The total hydrogen in volatile products including shale oil and pyrolysis gas increased with raising the heating rate, and the total volatile production was higher for the infrared quick heating pyrolysis (heating rate: 25 °C/s) than that for t...

Anthocyanins Based Indicator Sensor for Intelligent Packaging Application

Natural dyes extracted from the flower of rose and red cabbage were immobilized on filter paper as carrier to prepare a colorimetric sensor for application in intelligent packaging. Indicator sensor was based on natural flavonoids (anthocyanins) extracted from red cabbage and rose whose colour changed from red to green with increase in pH. On characterization of extracts by UV–Vis spectrophotometer, absorption maximum of 530 nm was observed which is ascribed to anthocyanin present in two extracts. The characteristics of sensor including response time, reproducibility, reversibility, stability towards light and the storage stability were also studied. Sensors were also kept in atmosphere of ammonia simulating total volatile basic nitrogen production which changed its colour from red to green with increase in pH. Since pH value of flesh foods concerns their freshness, the indicator sensor is expected to provide a convenient, non-destructive and visual method for flesh food spoilage in storage condition and also for the prediction of shelf life.

SARNET benchmark on Phébus FPT3 integral experiment on core degradation and fission product behaviour

The importance of computer simulations in the assessment of nuclear plant safety systems has increased dramatically during the last three decades. The systems of interest include existing or proposed systems that operate, for example, normal operation, in design basis accident conditions, and in severe accident scenario beyond the design basis. The role of computer simulations is especially critical if one is interested in the reliability, robustness, or safety of high consequence systems that cannot be physically tested in a fully representative environment. In the European 7th Framework SARNET project, European Commission (EC) co-funded from 2008 to 2013, the Phébus FPT3 experiment was chosen as a code benchmark exercise to assess the status of the various codes used for severe accident analyses in light water reactors.The aim of the benchmark was to assess the capability of computer codes to model in an integral way the physical processes taking place during a severe accident in a pressurised water reactor (PWR), starting from the initial stages of core degradation, fission product, actinide and structural material release, their transport through the primary circuit up to the behaviour of the released fission products in the containment.The FPT3 benchmark was well supported, with participation from 16 organisations in 11 countries, using 8 different codes. The temperature history of the fuel bundle and the total hydrogen production were well captured. No code was able to reproduce accurately the final bundle state, using as bulk fuel relocation temperature, the temperature of the first significant material relocation observed during the experiment. The total volatile fission product release was well simulated, but the kinetics were generally overestimated. Concerning the modelling of semi-volatile, low-volatile and structural material release, the models need improvement, notably for Mo and Ru for which a substantial difference between bundle and fuel release was experimentally observed, due to retention in the cooler upper part of the bundle. The retention in the primary circuit was not well predicted, this was due mainly the non-prototypic formation of a boron-rich blockage in the rising line of the FPT3 steam generator, simulated in the circuit as a single external cooled U tube. The deposition mechanism and the volatility of some elements (Te, Cs, I) could be better predicted.Containment vessel thermal hydraulics, designed in the experiment to be well-mixed, were well calculated. Concerning the containment aerosol depletion rate, only stand-alone cases (in which the input data were derived from experimental data) provided acceptable results, whilst the integral cases (in which the input data came from circuit calculations) tended to largely overestimate the total aerosol airborne mass entering the containment.The disagreement of the calculated total aerosol airborne mass in the containment vessel with the measured one is due to the combination of a general underestimation of the overall circuit retention and overestimation of fission product and structural material release.Calculation of iodine chemistry in the containment turned out to be a major challenge. Its quality strongly depends on the correct prediction of chemistry speciation in the integral codes. The major difficulties are related to the presence of high fraction of iodine in gaseous form in the primary circuit during the test, which is not correctly reproduced by the codes. This inability of the codes compromised simulation of the observed iodine behaviour in the containment.In the benchmark a significant user effect was detected (different results being obtained by different users of the same code) which had to be taken into account in analysing the results. This article reports the benchmark results comparing the main parameters calculated and observed, summarising the results achieved, and identifying the areas in which understanding needs to be improved. Relevant experimental and theoretical work is under way to resolve the issues raised.

Regulation of Spoilage-Related Activities of S hewanella putrefaciens and S hewanella baltica by an Autoinducer-2 Analogue, (Z)-5-(Bromomethylene)furan-2(5H)-One

Shewanella putrefaciens (SHP) and S. baltica (SHB) are involved in spoilage of refrigerated shrimp (Litopenaeus vannamei). The bacteria possess the luxS gene and produce autoinducer-2 (AI-2). (Z)-5-(bromomethylene) furan-2(5H)-one (BMF), an AI-2 inhibitor, significantly (P < 0.05) decreased luxS expression and AI-2 activities of SHP and SHB. BMF inhibited extracellular proteolytic activities, but increased biofilm formation. Total volatile basic nitrogen production and emission levels of some sulfuric compounds (dimethyl trisulfide, sulphuric acid dibutyl ester, methanethiol and methyl disulfide), aldehydes and ketones (acetone, acetaldehyde, methyl-glyoxal aldehydes), and alcohols (2-methyl-2-propanol, 3-methyl-1-butanol, 2-ethylhexan-1-ol) in shrimp meat samples inoculated with SHP and SHB were significantly (P < 0.05) decreased by the BMF treatment. Practical Applications Our findings provide evidence for the potential application of AI-2 inhibitors in prolonging the shelf life of fresh shrimp meat.