Wood Smokes Research Articles

The effect of liquid smoked flavourings and wood smoke on the quality of smoked mackerel fillets during chilled storage

This study was undertaken to evaluate the effects of liquid smoked flavourings and wood smoke on the sensory, color, texture, and lipid stability of smoked mackerel fillets for four weeks chilled storage. Fish fillets were smoked by two methods: (1) immersed in brine (1:1) containing 100 g/L NaCl at 0-5 °C for 3 hours, allowed to drain at room temperature (~20 °C) for 2 hours and smoked directly with wood smoke in a smoking chamber at 25 °C for 3 hours; (2) immersed in brine (1:1) containing 5 mL/L commercial liquid smoke flavourings and 60 g/L NaCl for 16 hours at 0-5 °C then dried at 25 °C for 2 hours in an oven. Smoked samples were then vacuum packed and stored chilled at -1 °C for one week, followed by 4±1°C for three weeks. The quality changes in sensory, color, texture, and lipid stability were observed after 0, 1, 2, 3 and 4 weeks of storage. The results showed that, smoked mackerel using commercial liquid smoked flavourings was higher in rancid flavour, lightness, redness, and yellowness but had less bitter odour and was softer than the wood smoked mackerel. The lipid oxidation was higher after the wood smoke process but was however rather stable during the chilled storage. In contrast, lipid oxidation in the liquid smoked products increased significantly during chilled storage. Keywords: Atlantic mackerel (Scomber scombrus), color, liquid smoked flavouring, lipid quality, sensory, texture, wood smoke

Impact of different smoke flavors on the quality of hermetically sealed green chili paste (Nam Prik Num)

This research examined how various smoke flavors such as powdered smoke, teak, and longan wood affected the quality of hermetically sealed green chili paste (Nam Prik Num). Teak and longan wood smoking produced a darker green color than the control and smoke powder samples. The smoky aroma had no impact on yield, pH, water release, or chemical composition. However, it did influence moisture content, lightness (L*), redness (a*), yellowness (b*), and water activity (aw) compared to control and smoke-flavored samples. The attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) showed structural changes, control with C-H groups at 2924 cm−1, and smoking introduced –COOR at 1744 cm−1, signifying flavor-induced alterations. The heightened peak hinted at a distinctive smoke aroma, deepening our understanding of molecular transformations. Sample smoke flavor compounds studied using a solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), included hydrocarbons, alcohol, aldehydes, ketones, esters, acids, and sulfide compounds, with sulfide compounds, alcohol, hydrocarbon, and alcohol compounds as the predominant volatiles. Nam Prik Num with smoke powder scored higher in appearance, color, aroma, taste, and texture than the control. Flavoring with smoke powder is more effective than charcoal grilling for adding smoky taste to Nam Prik Num.

Early Childhood in Marginalized Roma Communities: Health Risks and Health Outcomes.

This study aims to compare selected early childhood health risks and health outcomes of children from marginalized Roma communities (MRCs) in Slovakia with those of the majority. We obtained cross-sectional data from mother-child dyads from the majority (N = 109) and MRCs (N = 143) via questionnaires and from medical records. Socioeconomic status, health risks and health outcomes were compared using chi-square and Mann-Whitney U tests in SPSS. Mothers from MRCs reported significantly worse socioeconomic status. Air quality in the households in MRCs was significantly worse, affected by heating with stoves, burning fresh wood and indoor smoking. The diet composition of children from MRCs was characterized by shorter breastfeeding and unhealthy diet composition less fresh fruits and vegetables, more processed meat products, and sweet and salty snacks. Children from MRCs more often suffered from respiratory and diarrheal diseases, used antibiotics and were hospitalized. The health and healthy development of children living in MRCs is endangered by various poverty-related factors. Persistent differences in exposures and health in early childhood should be a priority goal of the state's social and health policies.

High loadings of carbonaceous aerosols from wood smoke in the atmosphere of Beijing from 2015 to 2017: Implications for energy transition policy

Recently, biomass has been regarded as a promising option for solid energy in China, which is promoted in the residential sector and firing power plants. We collected 200 PM2.5 samples (particulate matter with a aerodynamic diameter smaller than 2.5 μm) at multi-sites across Beijing from three individual sampling cases from 2015 to 2017. The levels of OC, OC fractions, EC, EC fractions, as well as K+ were measured. Then, we adopted the Positive Matrix Factorization 5.0 to apportion the sources of carbonaceous aerosols. The source apportionment results were compared with the estimates of source contribution using the bottom-up technical method with the latest emission inventories after the Action Plan was put into effect in 2013. Our results demonstrate that high pollution of carbonaceous aerosols originated from wood smoking based on the receptor modeling and bottom-up technical method in Beijing from 2015 to 2017. Future energy transition policy should focus on the technologies and regulations for reducing emissions from renewable biomass fuel combustion. This study highlights the importance of regulations that address emissions controls on fuels replacing coal combustion to meet the needs to mitigate air pollution from primary energy use.

Impact of the Smoking Process on Biogenic Amine Levels in Traditional Dry-Cured Chorizo

This study aimed to investigate the influence of various production stages on the quality and spoilage conditions of traditionally dry-cured chorizo. To accomplish this, we employed an experimental design that examined three key production parameters: the batch, the filling stage, and the food smoking process. The study was conducted in collaboration with a local producer who adheres to traditional curing methods utilizing oak wood smoke and heat. Biogenic amine levels were closely monitored throughout the process. This involved their extraction and derivatization through the salting-out technique, followed by identification and quantification using LC-ESI/MSn and HPLC-DAD, respectively. The findings suggest that both raw materials and the production process are well controlled during the filling stage. However, it became evident that the 14-day oak wood smoking period had a significant impact on biogenic amine formation, whose total mean values increased from 126 to 1385 mg kg−1, particularly with respect to putrescine (PUT), cadaverine (CAD), and tyramine (TYR), although these levels remained below the oral toxicity limit (2000 mg kg−1). Consequently, the concentration of these compounds can influence the quality and safety of traditionally dry-cured chorizos. Therefore, the combined levels of PUT, CAD, and TYR can serve as a valuable quality indicator for these products.

Reduction of Polychlorinated Biphenyls (PCB) In Fresh Fish from the Grand Lahou Lagoon for Healthy Consumption

The Grand Lahou lagoon system receives numerous spills from inland waters. This results in various forms of chemical pollution. Two species of fish most consumed by the Grand Lahou population are contaminated with high levels of Polychlorinated Biphenyls (PCBs). The objective of this study is to reduce the levels of PCBs in both fish species in order to provide consumers with healthy fish. The fish species most contaminated with PCBs, namely a type of catfish called ‘‘machoiron’’ (Chrysichthys sp.) and the mullet (Mugil sp.) were collected according to their weight (category 1:101-200g and category 2: 201-300g). Smoking has been proposed to reduce PCB levels. Thus two smoking techniques were used: smoking the fish traditionally using firewood as fuel and smoking on barbecue with charcoal. The level of PCB contamination in fish was determined by the gas chromatograph coupled with an electron capture detector (GC-ECD). The results obtained show that the smoking techniques used reduce the PCBi content. Wood smoking eliminates 98% of PCBs from fish compared to 88% for charcoal smoking.

Whey protein protects liver mitochondrial function against oxidative stress in rats exposed to acrolein.

Acrolein (AC) is one of the most toxic environmental pollutants, often associated with incomplete combustion of petrol, wood, and plastic, oil frying, and tobacco smoking, that causes oxidative damage to DNA and mitochondria. Considering that little is known about the protective effects of whey protein (WP) against AC-induced liver toxicity, the aim of our study was to learn more about them in respect to liver mitochondrial oxidative stress, respiratory enzymes, Krebs cycle enzymes, and adenosine triphosphate (ATP). To do that, we treated Sprague Dawley rats with daily doses of AC alone (5 mg/kg bw in 0.9 % NaCl solution), WP alone (200 mg/kg bw, in 0.9 % NaCl solution), or their combination by oral gavage for six days a week over 30 days. As expected, the AC group showed a drop in glutathione levels and antioxidant, transport chain, and tricarboxylic acid cycle enzyme activities and a significant rise in mitochondrial lipid peroxidation and protein carbonyl levels. Co-treatment with WP mitigated oxidative stress and improved enzyme activities. Judging by the measured parameters, WP reduced AC toxicity by improving bioenergetic mechanisms and eliminating oxidative stress.

Identification of aroma-active compounds in Cheddar cheese imparted by wood smoke

Cheddar cheese is the most popular cheese in the United States, and the demand for specialty categories of cheese, such as smoked cheese, are rising. The objective of this study was to characterize the flavor differences among Cheddar cheeses smoked with hickory, cherry, or apple woods, and to identify important aroma-active compounds contributing to these differences. First, the aroma-active compound profiles of hickory, cherry, and apple wood smokes were analyzed by solid-phase microextraction (SPME) gas chromatography-olfactometry (GCO) and gas chromatography-mass spectrometry (GC-MS). Subsequently, commercial Cheddar cheeses smoked with hickory, cherry, or apple woods, as well as an unsmoked control, were evaluated by a trained sensory panel and by SPME GCO and GC-MS to identify aroma-active compounds. Selected compounds were quantified with external standard curves. Seventy-eight aroma-active compounds were identified in wood smokes. Compounds included phenolics, carbonyls, and furans. The trained panel identified distinct sensory attributes and intensities among the 3 cheeses exposed to different wood smokes (P < 0.05). Hickory smoked cheeses had the highest intensities of flavors associated with characteristic "smokiness" including smoke aroma, overall smoke flavor intensity, and meaty, smoky flavor. Cherry wood smoked cheeses were distinguished by the presence of a fruity flavor. Apple wood smoked cheeses were characterized by the presence of a waxy, green flavor. Ninety-nine aroma-active compounds were identified in smoked cheeses. Phenol, guaiacol, 4-methylguaiacol, and syringol were identified as the most important compounds contributing to characteristic "smokiness." Benzyl alcohol contributed to the fruity flavor in cherry wood smoked cheeses, and 2-methyl-2-butenal and 2-ethylfuran were responsible for the waxy, green flavor identified in apple wood smoked cheeses. These smoke flavor compounds, in addition to diacetyl and acetoin, were deemed important to the flavor of cheeses in this study. Results from this study identified volatile aroma-active compounds contributing to differences in sensory perception among Cheddar cheeses smoked with different wood sources.

THE IMPACT OF STABLE FLIES (Stomoxys calcitrans L.) ON SMALL STOCK PRODUCTION IN BODIBENG, BOTHATOGO AND SEHITHWA IN THE NORTH WEST DISTRICT, BOTSWANA; A SURVEY STUDY

Stable fly, Stomoxys calcitrans L. (Diptera: Muscidae) is a globally recognized livestock pest of economic importance, which also attacks wild animals, pets and humans. These flies frequently feed on the forelegs of animals and can cause significant production losses and severe animal health and welfare concerns. This study investigated the impact of stable flies on small stock (sheep and goats) production and documented control measures adopted by farmers in Sehithwa, Bodibeng and Bothatogo villages in the North West District of Botswana. Simple Random Sampling was used to select 90 respondents in the study area. Data on demographic characteristics (i.e., age, sex, marital and educational status of the respondents), control measures against stable flies, time stable flies appeared, factors contributing to abundance of stable flies, and the role of government and private sector in the control of stable flies were collected and analysed using SAS. The Chi-square test of goodness of fit was used to show the unequal distribution of the frequencies of respondents among the categories for each variable. Results showed that wood smoking (53.33%) was the common control measure against stable flies followed by migration to unaffected areas (35.55%) and dipping (11.11%). Feeding activity of stable flies reached its peak in the evening (58.89%) followed by morning (31.11%), afternoon (6.67%) and the least was night (3.33%). Eighty-seven percent of respondents mentioned that stable fly contributed to poverty, starvation (16.67%) and loss of income (13.33%). It is concluded that stable flies affect livestock productivity and people’ livelihood; hence the need to adopt effective control measures. Control measures against these flies will be more effective when applied in the evening and morning.

Characterization and Storage Stability Study of Guava and Mango Wood Smoked Induced Spiced Cultured Milk (Raita)

A study was conducted to evaluate the effect of the smoking of raita with guava and mango wood on its functional properties and storage stability. The raita was smoked with guava and mango wood for 2.5, 5, 7.5, and 10 min in a closed chamber. The smoked raita was evaluated for change in titratable acidity (TA), pH, total phenolic content (TPC), antioxidant activity (DPPH), colour (L*, a*, and b*), and sensory attributes. Both guava and mango wood smoked samples didn’t show significant changes (P&lt;0.05) in TA, pH, TPC, and antioxidant activity. All colour values (L*, a* and b*) of smoked samples were significantly (P&lt;0.05) higher than the control sample, particularly, the yellowish attribute (b*) was very high in smoked samples. The sample that smoked for 7.5 min had very high overall acceptability scores in both kinds of wood and which is considered as an optimum smoking time for raita. The selected raita samples were stored for 9 days at 4°C and assessed for TA, pH, and standard plate count (SPC) at 3 days of interval. During the storage period, a significant reduction (P&lt;0.05) in pH and a significant increase (P&lt;0.05) in TA was seen till the 6th day of storage. The smoked samples had considerably lower SPC than the control sample and SPC was decreased significantly (P&lt;0.05) with an increase in storage days in all the samples. The preparation is simple and can be served in Pubs/Bars, Casual Dining Restaurants &amp; QSRs (Quick served restaurants).

Formaldehyde, acrolein and other carbonyls in dwellings of university students. Levels and source characterization

Fifteen carbonyl compounds were investigated in the living rooms and bedrooms of 25 university student flats in the urban area of Ciudad Real (Central Southern Spain) in wintertime. Carbonyls were sampled using Radiello ® passive samplers refilled in the laboratory according to the method described in ISO 16000-3 Standard. The most abundant carbonyls in the living rooms and bedrooms were formaldehyde, acetone, acetaldehyde, hexaldehyde and butyraldehyde. The median concentration levels in the living rooms and bedrooms were: 28.6 and 34.2 μg m−3 for formaldehyde, 18.3 and 23.1 μg m−3 for acetone, 14.3 and 15.8 μg m−3 for acetaldehyde, 11.4 and 14.1 μg m−3 for hexaldehyde and 10.8 and 12.4 μg m−3 for butyraldehyde. The median concentration of formaldehyde, benzaldehyde, valeraldehyde and hexaldehyde was significantly higher in the bedrooms than in the living rooms. Indoor concentrations were significantly higher than outdoor concentrations for all carbonyl measured, indicating that sources in the indoor environment are prevailing in all flats. Principal component analysis, multiple linear regressions and Spearman correlation coefficients were used to investigate the origin, the indoor pollutants determinants and to establish common sources between carbonyls.Eight components were extracted from the application of PCA to the indoor and outdoor measurements accounting for 97.7% of the total variance. Formaldehyde, acetone, acetaldehyde and acrolein presented different indoor sources. In the multiple linear regression analysis, higher formaldehyde concentrations were found in those living rooms with wood floor and smoking was positively associated to acetone, propionaldehyde, benzaldehyde and isovaleraldehyde. Formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde and benzaldehyde concentrations were compared with relevant international guidelines, being their concentrations below recommended values except acrolein, where all measured flats exceeded the reference levels; it would be important to focus on the characterization of emission sources of acrolein in indoor air in order to minimise the exposure and health risk.

Effect of Selected Wood Smoke on Physicochemical and Sensory Qualities of Tilapia (Oreochromis niloticus)

ABSTRACT Different preservation and processing techniques have been used to extend the shelf life of fish. Smoking is a technique that enhances the flavor, color, texture, and shelf life of fish. This study was conducted to identify specific smoking conditions for tilapia (Oreochromis niloticus), while comparing the physicochemical and sensory qualities of tilapia smoked using selected wood smokes. Tilapia fillets of the same thickness were obtained, and trials were conducted to identify the best brine concentration, temperature/time combination, and wood material. The fillets were immersed in brine containing 2.5, 5.0, 7.5, 10.0, and 12.5% (w/v) NaCl for 1 hour. Then, fillets were smoked with wood smoke at three different temperatures (50, 60, and 70°C) and three drying times (3, 4, and 5 hours) using a smoking oven. Based on the selected temperature/time combinations, tilapia were smoked using mahogany, cinnamon, or their combination (1:1). Final products were vacuum-packed and stored at 4°C for analysis. Quality changes in sensory attributes were tested by 30 untrained panelists. Microbial quality (Salmonella, Escherichia coli, and total plate count), thiobarbituric acid reactive substances assay, and color were determined during 21 days of chilled storage, and proximate analysis was conducted. Fish brined in 10% (w/v) NaCl and smoked at 60°C for 4 hours using mahogany: cinnamon at 1:1 had the best sensory qualities (p < .05). Microbial counts and lipid oxidation were within the permitted levels, while no Escherichia coli and Salmonella sp. were observed. During the chilled storage, an increase in lightness (40.85 ± 0.32 to 42.02 ± 1.22) was observed, whereas the redness (8.86 ± 0.69 to 6.84 ± 0.11) was decreased. In conclusion, immersing tilapia fillets in brine containing 10% (w/v) NaCl followed by smoking at 60°C for 4 hours using mahogany: cinnamon at 1:1 can be considered as the best conditions to produce smoked tilapia. However, further studies need to be done to compare the chemical changes that occurred due to smoking.

Long-term exposure to air pollutants (PM2.5and NO2) and incidence of type 2 diabetes in the Mexican Teachers’ Cohort.

Background/Aim: Air pollution is a risk factor for type 2 diabetes (T2D). However, no longitudinal studies have evaluated this association in a low- and middle-income countries, where 80% of the worldwide cases of T2D occur. Our aim was to evaluate the association between incident T2D and long-term exposure to PM2.5 and NO2 in the Mexican Teachers’ Cohort (MTC). Methods: We selected a subsample of female teachers from the MTC who lived and worked in the Mexico City Metropolitan Area, recruited in 2008 and with active follow-up every 3 years (n = 14,194). We assigned the time-weighted exposures (PM2.5 and NO2) in home and work addresses, from 12 months before baseline to failure or censoring. We developed two high resolution (1km x 1km) spatio-temporal predictive Generalized Additive Models of PM2.5 and NO2. We defined incident T2D when teachers self-reported at least two of the following questions: have a medical diagnosis, use of medical treatment, or date of diagnosis. We fitted time-varying Cox models to estimate hazard ratios of the relation between PM2.5 and NO2 and incident T2D; adjusting for confounding variables: age, passive and active smoking status, physical activity, SES, wood smoking and time spent outdoors. Results: Teachers were followed up for 11.5 years. There were 795 incident T2D cases (84 cases per 100,000 person-months). Incident T2D increased by 80% (HR = 1.8[1.6-2.1]) for each 10 μg/m3 increase of PM2.5 and 60% for every 10 ppb of NO2 (HR = 1.6[1.4-1.9]). In two-pollutant models, effects were attenuated. Conclusions: PM2.5 and NO2 increased the risk of T2D in Mexico, in a larger magnitude than previous published studies. Despite improvements in air quality, there are still health risks related to current pollutant levels, arguing for even stricter regulation.

Making life look and taste better

Making life look and taste better

Sensory characterization of specific wood smoke aromas and their contributions to smoked Cheddar cheese flavor

AbstractThis study characterized the sensory properties of different wood smokes and their application to smoked Cheddar cheese flavor. Sniff jars of wood smokes were created by exposing filter paper to 23°C smoke (cold smoke). Sensory attributes for nine wood smokes (apple, alder, cedar, cherry, hickory, maple, mesquite, oak, and pecan) were generated by a trained panel followed by projective mapping of the different wood smoke aromas. Four distinct wood smokes (mesquite, cherry, hickory, and cedar) were selected for cold smoking of 30 day old Cheddar cheeses. Cheeses were cold smoked at 23°C followed by descriptive analysis of flavor attributes using the trained panel. Nonparametric and parametric statistical analyses were applied to the collected data. Twelve attributes were selected to describe wood smoke aromas. The sensory descriptors for the cold smokes cited most often included: sweet aromatic, charcoal/charred, guaiacol, meaty, vanillin, and fresh tobacco. Mesquite, cherry, hickory, and cedar smokes were the most distinct smokes by projective mapping, and these smokes also imparted distinct flavors to smoked Cheddar cheeses. The mesquite smoked cheese was characterized by high smoke aroma and the highest meaty/brothy flavor, the cherry smoked cheese was distinguished by campfire/marshmallow flavor, the hickory smoked cheese had high campfire/marshmallow and meaty flavors, and the cedar smoked cheese was characterized by an intense resinous flavor. The determination of sensory properties of different wood smokes demonstrates the differences in specific smoke flavor contributions to cheese. Furthermore, the determination of the sensory properties specific to smoked cheese will provide a platform to understand consumer perception of smoked cheeses.Practical ApplicationsSmoked foods are a growing category. This study demonstrated that smokes from different wood sources have distinct aromas that can be differentiated and that these distinct smoke aromatics are imparted to cheeses exposed to different wood smokes. Results from this study provide a sensory language to differentiate aromatics from different wood smokes and may be useful to product developers and food manufacturers seeking to position and differentiate smoked foods.

Effects of fire wood and charcoal smoking on the polycyclic aromatic hydrocarbon and fatty acid profiles of mud fish

Cooking methods have been linked with the presence of PAHs in some foods. Mud fish is one of the major components of delicacies in Western part of Nigeria. It is either cooked or smoked for consumption. Not much study has been carried out to determine the effect of methods of preparation on the level of PAHs concentration in mud fish. Fresh mud fish was purchased in Ogbomoso and smoked for 1, 2, 3 and 4h respectively at a temperature range of 200 oC – 210 oC with the use of Azadirachta indica wood and charcoal. A representative portion of about 10 g of sample was taken from the homogenized sample and extracted with ultrasonicator using three solvent systems: methanol, methanol: dichloromethane (1:1v/v) and dichloromethane. The aromatic and the free fatty acid fractions were subsequently analyzed with Gas Chromatography (GC/FID). PAHs and FFA were quantified and used to monitor the impact of the type of biomass used in smoking the mud fish. The result showed that 24 PAHs were detected in all the samples except in firewood smoked mud fish (FSMF) 1hr and charcoal smoked mud fish (CSMF) 1h – 4h where benzo[j]fluoranthene was below detection limit. The total PAHs found in all smoked mud fish in this study were higher than what was found in fresh [control] fish. Amount of PAHs in samples smoked with wood was significantly different from samples smoked with charcoal. The main compounds of free fatty acids present in the samples were myritic acid, palmitic acid, stearic acid and linoleic acid. The concentration of PAHs with 2 – 3 rings were less than the PAHs with 4 – 6 rings, with pyrene, benzo[c]phenanthrene and indeno(1,2,3 – cd) pyrene being the most abundant compounds. The phenanthrene/anthracene ratio for FSMF ranged from 0.27 – 9.02 and 0.72 – 1.66 for CSMF which suggests the source of the PAHs was pyrolitic. Also, Fluoranthene/fluoranthene + pyrene ratio ranged from 0.00 – 0.54 in FSMF and 0.01 – 0.99 for CSMF samples which equally suggests a pyrolytic source. From the proximate analysis results, the crude protein for the UPMF is 28.27 which increases gradually to 47.7 % in FSMF 4h and increased to 65.94 % in CSMF 4h. The crude fiber of all the samples both processed and unprocessed were generally low than expected. The percentage composition of fat increased from 1.01 % in fresh sample to 6.04 % in CSMF 4h.

Risk factors associated with actinic prurigo: a case control study.

BackgroundActinic prurigo (AP) is an idiopathic photodermatosis. Although its initial manifestations can appear in 6 to 8-year-old children, cases are diagnosed later, between the second and fourth decades of life, when the injuries are exacerbated.ObjectiveTo identify risk factors associated with clinical manifestations of AP such as skin and mucosal lesions.MethodsThirty patients with AP and 60 controls were included in the study, the dependent variable was the presence of skin or labial mucosal lesions, the independent variables were age, sex, solar exposure, living with pets or farm animals, exposure to wood smoke, smoking habit, years smoking, and hours spent per day and per week in contact with people who smoke.ResultsOf the 30 diagnosed AP patients, 66.7% were female. Patients age ranged from 7 to 71 years and the mean age was 35.77 ± 14.55 years. We found significant differences with the age and cohabitation with farm animals. Those who lived with farm animals presented 14.31 times higher probability of developing AP (95% CI 3-78.06).Study limitationsThis is a case-control study; therefore, a causal relationship cannot be proven, and these results cannot be generalized to every population.ConclusionsThe identification of factors related to the development of AP increases our knowledge of its physiopathology. Moreover, identifying antigens that possibly trigger the allergic reaction will have preventive and therapeutic applications in populations at risk of AP.

Determination of Benzo(a)pyrene Levels in Smoked Clarias gariepinus and Heterotis niloticus in Hadejia Jigawa State and Geriyo Adamawa State

This study determined the levels of benzo(a)pyrene in smoked Clarias gariepinus and Heterotis niloticus. Questionnaire was administered to fish processors at the Hadejia and Geriyo fish processing units, the result obtained from analysis of the questionnaire shows that majority of the fish processors in Hadejia are using Neem tree (Azadrachta indica) wood and rectangular smoking kiln while in Geriyo majority of the fish processors are using Chew stick tree (Anageisus leiocarpus) wood and Drum smoking kiln. Sample of fish processed were collected and also fresh fish were processed using the type of firewood commonly used by the fish processors. The Fresh fish samples were used as control. All the smoked and fresh fish samples were subjected to laboratory analysis to determine the level of benzo(a)pyrene. Data generated were subjected to One-way ANOVA. The results obtained show that highest Benzo(a)pyrene recorded in this study is from C. gariepinus smoked in Hadejia market having 14.91 μg/kg followed by the same species smoked in Geriyo with 13.69 μg/kg of BaP while the lowest was recorded in H. niloticus smoked with chew stick with 7.61μg/kg. There is significant difference (p<0.05) in the level of BaP in smoked Clarias gariepinusand Heterotis niloticus across the samples. All the smoked fish samples examined in this study were found to be higher than the acceptable limit (5 μg/kg) specified by the European Union commission, but when they were evaluated according to FAO/WHO limits (10 μg/kg). Four samples (40%) analyzed were over the acceptable limit. This result is recommending the smoking of fish using Chew stick wood for reduction in the BaP levels in the food product.

Multi-angle, dual wavelength scattering measurement chamber for the structural measurement of combustion generated particles

Soot particles are formed through combustion processes and have fractal-like shapes. They influence our climate by absorption and scattering of the solar radiation directly, and indirectly by their influence on cloud (liquid or glaciated) formation and their deposition on snow and ice surfaces. An Instrument, which we would like to introduce in this paper was developed and built at the University of Applied Sciences Northwestern Switzerland to measure light scattering properties of combustion type aerosols. A closed chamber was designed where the scattered light can be detected at 7 fixed, predefined angles simultaneously. Two lasers at 405nm and 852nm serve as light sources, and with that almost simultaneous measurements at the two different wavelengths can be carried out. The instrument is calibrated with aerosol particles of known scattering properties and concentration. We used nebulized, size selected ammonium sulphate particles for this purpose.The angular light scattering is influenced by the shape of the particles. In the case of fractals information on the fractal dimension and characteristic size can be derived from the angle dependence of the scattered light. In this paper we demonstrate and test the performance of this new light scattering instrument through the measurement of different soot or soot–containing aerosols. These examples include the measurement of artificial soot particles generated by two different soot generators (Cast soot and Palas soot generators) and different kind of combustion produced aerosols like: flaming ethanol, smouldering wood and mixed smouldering/flaming wood smokes.

Stability study of smoked fish, horse mackerel (Trachurus trachurus) by different methods and storage at room temperature

The present study assessed the effect of hot smoke using wood and charcoal dry heat on keeping quality of Trachurus trachurus fish fillet, skin, head and bones (SHB). T. trachurus was smoked using the altona kiln at 80 to 105°C for eight hours, placed in cain woven baskets to cool off, packaged in sealed transparent polythene bags and left on shelf for 7 days at ambient temperature (32 ± 2°C). Biochemical indexes assayed were: pH, total volatile nitrogen (TVBN), peroxide value (PV) and total viable count (TVC). pH of raw T. trachurus fillet was 6.85 ± 0.00 but significantly reduced with wood smoke at day 0 to 6.70 ± 0.02, while TVBN in raw T. trachurusfillet was 27.17 ± 1.61 mgN/100 g. After smoking, TVBN of T. trachurus fillet at day 0 was 21.83 ± 0.38 mgN/100 g (wood) and 23.05 ± 1.36 mgN/100 g (charcoal). pH of raw T. Trachurus SHB was 5.87 ± 0.03 and increased (p<0.05) with smoking, that is, 6.43 ± 0.21 (wood) and 6.43 ± 0.00 (charcoal). TVBN in the raw T. Trachurus SHB was 28.12 ± 2.17 mgN/100 g, and after smoking on day 0, it was 31.90 ± 0.3 mgN/100 g (wood smoked) and 24.44 ± 1.90 mgN/100 g (coal smoked). The PV was highest in charcoal smoked SHB (CSHB) of T. trachurus at day 5(108.40±36.80) and TVC was highest in the CSHB on day 5 (3.48 logcfu/g). The overall study showed that T. trachurus fish samples (fillet and SHB) prepared via charcoal smoking method had the lowest (p<0.05) storage time amongst the smoked fish samples, when compared with those that were processed via wood smoke. Key words: Trachurus trachurus, ambient temperature, smoked fish and seafood quality.