Specific Loss Rate Research Articles

Effect of biochar filler on improving the power production efficiency of SMFCs

In this paper, the promotion effect of different biochar fillers on the electric generation performance of sedimentary microbial fuel cells (SMFCs) was studied. Three different biochar types were successfully prepared by high temperature pyrolysis and acidification modification technology. In order to evaluate their application value in improving the power generation efficiency of SMFCs, not only the specific surface area and weight loss rate of these biochar were measured. The output voltage, polarization curve and power density curve were also analyzed. The results showed that the specific surface areas of corn stalk, peanut shell and walnut shell were 24.66 m2/g, 3.90 m2/g and 3.67 m2/g, respectively. The SMFCs output voltages of the three biochar fillers were 0.16 V, 0.13 V and 0.19 V, respectively. The power density of SMFCs was higher than that of blank group (0.01 V). Moreover, the power density of SMFCs of corn stalk filler is as high as 91 mW/m3, which is nearly twice that of blank group (48 mW/m3). And the internal resistance of SMFC with corn stalk fillers (3981.63 Ω) is also lower than that of the other groups. It can be seen that biochar fillers can further optimize the power generation performance of sedimentary microbial fuel cells, and provide a new choice for the development direction of low-cost, green and clean SMFC.

Cultivation of Seaweed Kappaphycus alvarezii with Various Substrates Different on Laboratory Scale

Kappaphycus alvarezii is an important red algae and can be used as one of the primary raw materials in fisheries. It is widely cultivated because of its relatively cheap production technology, and post-harvest handling is simple and easy. This algae has excellent economic value for carrageenan producers. Carrageenan is used as a food ingredient, cosmetics, and medicine. The success of cultivating K. alvarezii seaweed can be achieved if a suitable environment for its growth supports it. One of the environmental aspects that influence the growth of K. alvarezii seaweed is the bottom substrate of the waters. This research aims to analyze the best substrate for cultivating green K.alvarezii seaweed on a laboratory scale. This research used an experimental method with a Completely Randomized Design (CRD) consisting of 4 treatments and three repetitions, resulting in 12 experimental units. The treatments tested were different substrates: a coral substrate, a sand substrate, a volcanic rock substrate, and a coral sand substrate. The results of this study showed that the average survival rate in various substrate treatments ranged from 7.16% to 39%, final weight ranged from 1.43 g to 7.8 g, specific loss rate ranged from -3.157%/day to -5.124%/day, carrageenan yield ranged from 6.8% to 18.4%, and thallus tissue showed that all treatments still showed the presence of cortex and medullary tissue with varying shapes and structures

Modeling and Optimizing the Performance of Green Forage Maize Harvester Header Using a Combined Response Surface Methodology–Artificial Neural Network Approach

Green forage maize harvesters face challenges such as high soil humidity and soft soil in the field, mismatched working parameters, and poor reliability and adaptability. These challenges often result in header blockage, significant harvest loss, and increased energy consumption. Traditional testing and statistical analysis methods used in most existing studies are limited by complex test processes, their time-consuming nature, high costs, and poor prediction accuracy. To address these problems, a test bench was constructed to analyze the effects of forward speed, cutting height, number of rows, and their interactions on specific energy consumption and harvest loss of the green forage maize (GFM) header. A combined response surface method (RSM)–artificial neural network (ANN) approach is proposed for modeling and predicting the performance parameters of the header. The optimal conditions were determined by optimizing the specific energy consumption and loss rate. The optimal combination parameters are a forward speed of 1.6 km/h, a cutting height of 167 mm, and a number of rows of 4. However, RSM–ANN has larger R2 values and lower root mean square errors (RMSE) and mean square errors (MSE) compared to RSM. Specifically, the R2 of the RSM–ANN model for specific energy consumption and loss rate a 0.9925 and 0.9906, MSE are 0.00001775 and 0.004558, and RMSE are 0.004214 and 0.006752, respectively. The results show that the combined RSM–ANN method has higher precision and accuracy and can better predict and optimize the header performance. This study overcomes the limitations of traditional methods and has the potential to provide data and method references for the design, optimization, prediction, and intelligent diagnosis of faults in the operational parameters of agricultural machinery.

An examination of microstructure, microhardness and tribological properties of ceramic reinforced bronze matrix composite materials

In order to obtain better mechanical properties in a bronze alloy, it is important to produce new materials by adding reinforcements and to offer these materials to the industry. In this study, bronze matrix (Cu10Sn) materials were reinforced with boron carbide (B4C) and silicon carbide (SiC) ceramic materials by using the mechanical alloying method. New composite materials were produced by powder metallurgy method by adding ceramic reinforcement (B4C and SiC) at 1, 2, 4 and 8 weight ratios to Cu10Sn alloy, which is the main matrix material. The obtained composite materials examined in terms of structural, microhardness and wear resistance. Coefficient friction, specific wear rate and volume loss rates under 5N, 10N, and 15N loads were examined for the samples produced. When the applied microhardness and wear behaviors were examined, it was generally seen that the hardness and wear behaviors were improved with the added reinforcement ratios. In line with the examinations made, based on the hardness and wear processes applied to the materials consisting of the bronze matrix of the reinforcement material, it was observed that the most appropriate results were obtained from composite materials (Alloy 4 and Alloy 8), which contain 4% B4C and SiC reinforcement.

Applied smouldering for co-waste management: Benefits and trade-offs

Smouldering combustion is emerging as a valuable application for many environmentally beneficial purposes, including waste-to-energy. While many applied smouldering systems rely on small fractions of fuel mixed within inert porous media (IPM) like coarse grain silica sand, there is also an opportunity to pursue co-waste management with much higher fuel loadings. This study explores these co-waste systems by blending non-smoulderable wastes (e.g., sewage sludge) with smoulderable wastes (e.g., construction waste woodchips) to form porous solid fuels (PSFs). Key differences between these IPM and PSF systems were identified by contrasting the temperature profiles in space and time, specific mass loss rates, and emissions profiles across experiments in multiple reactors (with 0.054, 0.080, and 0.300 m radii). For example, the PSF systems exhibited higher throughputs, a more straightforward path towards continuous operation, improved scalability, and higher production of potentially useful by-products (e.g., CH4, H2) than the IPM systems. However, the PSF systems were more sensitive to extinction and exhibited lower fuel moisture content limitations than the IPM systems. Altogether, this study illuminates the benefits and trade-offs of co-waste smouldering.

Numerical investigation on radiative and evaporative characteristics of a liquid droplet radiator through Monte-Carlo method

The liquid droplet radiator (LDR), a frameless heat dissipation device, is regarded as a preferred heat control solution for megawatt-scale space power systems. Accurate calculation of evaporation loss in the droplet layer is important for LDR systems since it determines the operating life of the LDR. In the present work, a novel model based on the Monte-Carlo Method (MCM) was developed to calculate the evaporation loss of the droplet layer. Compared to previous work in the literature, this model considers the evaporation loss of the droplet layer in the thickness and length directions. The radiative heat transfer characteristics of the droplet layer are also studied. The effects of optical thickness, operation temperature, and flight time on the droplet layer's heat transfer and evaporation processes were obtained and analyzed. The calculation results show that the temperature difference between the center and the edge of the droplet layer is larger than 65 K when the optical thickness is greater than 5. The heat dissipation power no longer varies significantly when the optical thickness of the droplet layer is greater than 6. The region with a negative specific evaporation loss rate accounts for 55.2 %, 58.2 %, and 0 for the whole droplet layer with optical thicknesses of 10, 5, and 0.2, respectively. The main evaporative loss comes from the beginning 5 m of the droplet layer. This paper may provide favorable reference to the design and optimization of the LDR systems.

Experimental analysis on combustion characteristics of diesel and kerosene under different radiation intensity of heat source

With the help of cone calorimeter, combustion experiments of 0# diesel and kerosene (3# jet fuel) under external heat radiation were completed, and the main combustion performance parameters, such as heat release rate, specific mass loss rate, effective heat of combustion, time to ignition, combustion duration and fire spread risk, were obtained under different heat source radiation intensities. The change rules of the main combustion characteristics of these tow fuels with the increase of heat source radiation intensity were discussed, and the differences of the main combustion characteristics between the diesel and kerosene were compared and analyzed. The results show that the average heat release rate, peak heat release rate and specific weight loss rate of the diesel and kerosene increase linearly with the increase of heat source radiation intensity, and the increasing trend (slope) of kerosene is larger than that of diesel. The time to reach the peak heat release rate, ignition time and combustion duration of the both fuels decreased exponentially with the increase of heat source radiation intensity. Under the same radiation intensity, the heat release rate, specific mass loss rate and effective heat combustion of kerosene are higher than those of diesel, while the time to reach the peak heat release rate, ignition time and combustion duration of kerosene are lower than those of diesel. The total heat release of kerosene is higher than that of diesel under different heat source radiation intensities, and the average total heat release of kerosene is about 6.17% higher than that of diesel. THR/tlast and pkHRR/TTI of the two fuels showed an exponential relationship, and the fire spread risk of diesel was less than that of kerosene.

Process optimization, exergy and economic analysis of boil-off gas re-liquefaction processes for LNG carriers

A re-liquefier based on the reverse Brayton cycle is the first choice for the re-liquefaction process owing to its compactness, simplicity, and safety. However, due to the low efficiency of the heat exchangers, the energy consumption of the re-liquefaction process is relatively high. Therefore, a novel cascade nitrogen expansion re-liquefaction process with high heat exchange efficiency is proposed and compared with the parallel expansion process. In the designed process, the condensation and subcooling stages of the boil-off gas (BOG) are performed in different heat exchangers. The performance improvement of the designed process is analyzed using the Aspen HYSYS and the genetic algorithm is used to optimize the processes. The optimization results show that the specific energy consumption (SEC) and exergy loss rate of the designed process are 0.727 kWh/kgLNG and 148.14 kW, which are 11.7% and 16.7% lower than those of the reference process, respectively. Moreover, the exergy efficiency (EXE) of the designed process is 0.352, which is 13.2% higher than that of the reference process. Because of the higher EXE and lower refrigerant demand, the designed process saves 7.2% of the total annual costs consisting of annual capital and operating costs compared with those of the reference process.

A screening model for managing periodic pesticide application in residential lawn soils

To improve our understanding of the fate of pesticides after household applications and to promote lawn management practices, we have introduced a periodic modeling framework that can be simplified using a weighted approximate approach. The comparisons of the periodic model and approximate method using regular rainfall or irrigation conditions demonstrate the validity of the approximate method; based on this, the overall weighted specific loss rate and half-lives of over 3,000 organic compounds were derived. The half-lives derived from the approximate approach can be conveniently used to estimate the pesticide concentrations that remain in lawn soils. For example, over 1,500 organic compounds have estimated half-lives below 7.0 days, indicating that their concentrations will be below at least 1/16 of the initial concentrations in soils if the applications follow a monthly pattern. The model results for two common herbicides, glyphosate and 2,4-D, indicated that when following the manufacturer's suggestions, the pesticide concentration in the soil may not cause the adverse health effects modeled by the children's ingestion exposure route. For example, based on a monthly application pattern of 230 mg m−2 per event, the average concentration of glyphosate was far below the simulated safe level of 12,000 mg kg−1, even on the days immediately after the glyphosate application. However, the simulated concentrations in the lawn soils were larger than some legal limits for glyphosate in the residential soils. Although this simple model requires further validation and improvements using field data, we hope that it will help to improve future pesticide management for lawn soils.

Postharvest Water Loss of Wine Grape: When, What and Why.

In postharvest science, water loss is always considered a negative factor threatening fruit and vegetable quality, but in the wine field, this physical process is employed to provide high-quality wine, such as Amarone and Passito wines. The main reason for this is the significant metabolic changes occurring during wine grape water loss, changes that are highly dependent on the specific water loss rate and level, as well as the ambient conditions under which grapes are kept to achieve dehydration. In this review, hints on the main techniques used to induce postharvest wine grape water loss and information on the most important metabolic changes occurring in grape berries during water loss are reported. The quality of wines produced from dried/dehydrated/withered grapes is also discussed, together with an update on the application of innovative non-destructive techniques in the wine sector. A wide survey of the scientific papers published all over the world on the topic has been carried out.

Ecological and evolutionary dynamics in advective environments: Critical domain size and boundary conditions

<p style='text-indent:20px;'>We consider the ecological and evolutionary dynamics of a reaction-diffusion-advection model for populations residing in a one-dimensional advective homogeneous environment, with emphasis on the effects of boundary conditions and domain size. We assume that there is a net loss of individuals at the downstream end with rate <inline-formula><tex-math id="M1">\begin{document}$ b \geq 0 $\end{document}</tex-math></inline-formula>, while the no-flux condition is imposed on the upstream end. For the single species model, it is shown that the critical patch size is a decreasing function of the dispersal rate when <inline-formula><tex-math id="M2">\begin{document}$ b \leq 3/2 $\end{document}</tex-math></inline-formula>; whereas it first decreases and then increases when <inline-formula><tex-math id="M3">\begin{document}$ b &gt;3/2 $\end{document}</tex-math></inline-formula>. <p style='text-indent:20px;'>For the two-species competition model, we show that the infinite dispersal rate is evolutionarily stable for <inline-formula><tex-math id="M4">\begin{document}$ b &lt; 3/2 $\end{document}</tex-math></inline-formula> and, when dispersal rates of both species are large, the population with larger dispersal rate always displaces the population with the smaller rate. For certain specific population loss rate <inline-formula><tex-math id="M5">\begin{document}$ b&lt;3/2 $\end{document}</tex-math></inline-formula>, it is also shown that there can be up to three evolutionarily stable strategies. For <inline-formula><tex-math id="M6">\begin{document}$ b&gt;3/2 $\end{document}</tex-math></inline-formula>, it is proved that the infinite random dispersal rate is not evolutionarily stable, and that, for some specific <inline-formula><tex-math id="M7">\begin{document}$ b&gt;3/2 $\end{document}</tex-math></inline-formula>, a finite dispersal rate is evolutionarily stable. Furthermore, for the intermediate domain size, this dispersal rate is optimal in the sense that the species adopting this rate is able to displace its competitor with a similar but different rate. Finally, nine qualitatively different pairwise invasibility plots are obtained by varying the parameter <inline-formula><tex-math id="M8">\begin{document}$ b $\end{document}</tex-math></inline-formula> and the domain size.

Tribological response of waste tire rubber as micro-fillers in automotive brake lining materials

Elastomeric materials show promise as potential micro-fillers in brake linings. They can provide vibration damping and acoustic advantages in intermittent and abrupt impact applications such as braking. The elastomeric material can be salvaged from non-biodegradable automotive tires, thereby providing an opportunity to reuse materials that will otherwise be discarded in landfills. Both tribological and thermomechanical performances of the waste tire rubber were assessed to determine their potential for use as micro-fillers in the brake linings of commercial vehicles with a gross weight less than 16 tons. Accordingly, the brake lining materials were fabricated with fine waste tire rubber particulates (WTRPs) as the micro-fillers, phenolic-R resin as the binder, graphite as the dry lubricant, laterite as the co-filler, and coconut coir for natural fiber reinforcement. The effects of increasing the WTRP weight fraction on the brake response of the linings were analyzed, and the different compositions were benchmarked against a commercial brake lining. Mechanical characterization comprising compressive strength, hardness, density, and porosity studies were carried out. Frictional and wear characteristics of the linings were analyzed using a rotary tribometer with simultaneous thermal monitoring. The manufactured lining with 15 wt% WTRPs exhibited a mean friction coefficient of ~0.38, a specific volumetric loss rate of 1,662 µm3/(N·m), and improved thermal response. Using optical microscopy and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), wear surface morphology studies compared the relative development of primary and secondary plateaus and revealed the redistribution of wear debris, leading to the stability of the coefficient of friction.

Corrosion decomposition and mechanical behaviors of As‐cast Mg–xZn–Zr alloys

AbstractDeveloping new‐type alloy materials with excellent decomposition properties and mechanical behaviors is a thorny issue for preparing fracturing balls in oil exploitation. As‐cast Mg–xZn–Zr alloys designed by regulating Zn contents have been fabricated in this study. Compressive strength and immersion corrosion test have been investigated to assess their feasibility as decomposition materials. Scanning electron microscopy and X‐ray diffract meter have also been used to characterize surface morphologies and phase structures for determining their decomposition mechanism. Results show that matrix phases and secondary phases with discontinuous reticular features form on the alloys. They also achieve excellent mechanical properties to ensure stability and pressure‐maintaining capacity in the decomposition process in chloride environment. Meanwhile, with Zn content and immersion time increasing, galvanic corrosion effect strengthens leading to accelerated specific mass loss rates of the alloys. Rapid corrosion decomposition of the alloys mainly attributes to anodic dissolution of matrix phases, exfoliation of microparticles, and poor resistance of corrosion products to the decomposition process. This study provides positive insight into the preparation of new‐type Mg alloys for guaranteeing fast decomposition of fracturing balls and also ensuring their compressive strength stability.

Dependence of microalgae culture specific endogenous loss rate and gross productivity on irradiance

Microalgal growth rate is determined by the difference between gross productivity and endogenous biomass loss rate. Gross productivity is a function of surface irradiance and reaches the maximal value under saturating light intensity. Endogenous biomass consumption of microalgal cells is mainly due to the respiration which can be sub-divided into growth and maintenance respiration. The paper proposes equations for calculating microalgae culture gross productivity and specific loss rate based on production characteristics. Verification of the obtained equations was performed for Arthrospira platensis and Dunaliella salina cultivated under constant illumination with different irradiance. It was demonstrated that gross productivity and specific loss rate increase linearly with increasing irradiance. Specific loss rate varied from 0,01 to 0,58 h-1 in A. platensis and from 0,04 to 0,35 day-1 in D. salina. Specific maintenance respiration rate was determined to be 0,01 h-1 in A. platensis and 0,01–0,04 day-1 in D. salina. The proposed calculation method enables a sufficiently accurate determination of productivity and loss rates based on culture density dynamics measures.

Analysis of Weather-Type-Induced Soil Erosion in Cultivated and Poorly Managed Abandoned Sloping Vineyards in the Axarquía Region (Málaga, Spain)

New trends related to market incomes, cultural human development, non-sustainable soil management practices, and climate change are affecting land abandonment in Mediterranean sloping vineyards. It is generally accepted that hydrological processes and, subsequently, soil erosion rates are usually different between cultivated and abandoned soils. However, these alterations are still poorly studied in relation to the general weather conditions in vineyards and abandoned vineyards. Thus, the main goals of this research are to (1) estimate the differences in soil properties, (2) quantify water and soil losses due to rainfall and specific soil management practices, and (3) analyze which kind of weather type and rainfall event is able to generate specific surface flows and soil loss rates. To achieve these goals, we focused on the specific case of the sloping vineyards of the Montes de Málaga (South Spain). We used 4 paired-erosion plots with Gerlach troughs to quantify soil loss and surface flow and conducted an analysis of the weather conditions during each rainfall event. The weather types that generated the highest amount of rainfall in the studied area came from the western (32.6%) and southeast (28.2%) types. The low rainfall events came from the south type (5.9%) and at the 500 hPa level, whereas the rainiest ones came from the southwest (47.7%) and south (34.1%). It is confirmed that there is a bimodality in the rainfall patterns. The results of soil erosion showed that there is a mixed mechanism depending on the state of the soil (vegetation cover, compaction, and initial soil moisture), soil management (tillage, trampling effect, and the use of herbicides). It is observed that the intensity of surface flow is highly correlated to the total rainfall amount and intensity. In the poorly managed abandoned plot, it is important to remark that the effect of tillage in the past, the elimination of the vegetation cover to preserve the soil in bare condition, and its use as a grazing area by cultivating barley highly affects the generation of the highest erosive events. Therefore, it is confirmed that these soil management options are not the most sustainable way to conserve the soil after the abandonment of cultivation.

Numerical-experimental analysis of a carbon-phenolic composite via plasma jet ablation test

Materials used in space vehicles components are subjected to thermally aggressive environments when exposed to atmospheric reentry. In order to protect the payload and the vehicle itself, ablative composites are employed as TPS (Thermal Protection System). The development of TPS materials generally go through phases of obtaining, atmospheric reentry tests and comparison with a mathematical model. The state of the art presents some reentry tests in a subsonic or supersonic arc-jet facility, and a complex type of mathematical model, which normally requires large computational cost. This work presents a reliable method for estimate the performance of ablative composites, combining empirical and experimental data. Tests of composite materials used in thermal protection systems through exposure to a plasma jet are performed, where the heat fluxes emulate those present in atmospheric reentry of space vehicles components. The carbon/phenolic material samples have been performed in the hypersonic plasma tunnel of Plasma and Process Laboratory, available in Aeronautics Institute of Technology (ITA), by a plasma torch with a 50 kW DC power source. The plasma tunnel parameters were optimized to reproduce the conditions close to the critical re-entry point of the space vehicles payloads developed by the Aeronautics and Space Institute (IAE). The specimens in study were developed and manufactured in Brazil. Mass loss and specific mass loss rates of the samples and the back surface temperatures, as a function of the exposure time to the thermal flow, were determined. A computational simulation based in a two-front ablation model was performed, in order to compare the tests and the simulation results. The results allowed to estimate the ablative behavior of the tested material and to validate the theoretical model used in the computational simulation for its use in geometries close to the thermal protection systems used in the Brazilian space and suborbital vehicles.

Mesoporous tungsten oxynitride as electrocatalyst for promoting redox reactions of vanadium redox couple and performance of vanadium redox flow battery

For enhancing the performance of vanadium redox flow battery (VRFB), a sluggish reaction rate issue of V2+/V3+ redox couple evaluated as the rate determining reaction should be addressed. For doing that, mesoporous tungsten oxide (m-WO3) and oxyniride (m-WON) structures are proposed as the novel catalysts, while m-WON is gained by NH3 heat treatment of m-WO3. Their specific surface area, crystal structure, surface morphology and component analysis are measured using BET, XRD, TEM and XPS, while their catalytic activity for V2+/V3+ redox reaction is electrochemically examined. As a result, the m-WON shows higher peak current, smaller peak potential difference, higher electron transfer rate constant and lower charge transfer resistance than other catalysts, like the m-WO3, WO3 nanoparticle and mesoporous carbon, proving that it is superior catalyst. Regarding the charge-discharge curve tests, the VRFB single cell employing the m-WON demonstrates high voltage and energy efficiencies, high specific capacity and low capacity loss rate. The excellent results of m-WON are due to the reasons like (i) reduced energy band gap, (ii) reaction familiar surface functional groups and (ii) greater electronegativity.

Turbidostat operation of outdoor pilot-scale photobioreactors

The effect of biomass concentration on areal productivity and photosynthetic efficiency of Nannochloropsis sp. CCAP211/78 was studied in three outdoor pilot-scale photobioreactors: an open raceway pond (OPR), a horizontal tubular (HT) photobioreactor and a vertically stacked horizontal tubular (VT) photobioreactor. The reactors were operated continuously as turbidostat at different biomass concentrations. For all systems highest areal productivities were obtained on days with a high light intensity, while the highest photosynthetic efficiencies were obtained on days with a low light intensity. Ground areal biomass concentration exceeding 51gm−2 had a negative effect on the areal productivity and photosynthetic efficiency. No significant effect of biomass concentration on the productivity was found for the HT at ground areal biomass concentration lower than 51gm−2. Also for the VT, no significant effect of biomass concentration was found with the exception of the highest biomass concentration of 2.0gL−1 (68gm−2) resulting in decreased productivity. For the open raceway pond the highest biomass concentration (0.5gL−1 or 94gm−2) resulted in significantly lower areal productivity, compared to the lower biomass concentration (0.25gL 47gm−2). Highest areal productivities were obtained for OPR and VT, most likely due to more efficient light interception. In this study we observed that night biomass loss was coupled to net growth. At lower biomass concentrations and concomitant higher growth rates the specific biomass loss rate was higher. Microalgal specific light absorption coefficient was correlated to biomass concentration; higher biomass concentrations resulted in higher specific absorption coefficients, resulting in a steeper light gradient in the microalgal cultures.

탈지 인삼씨박 분말을 첨가한 영양바의 품질 특성

Abstract The objectives of this study were to investigate the quality characteristic of the nutrition bar with various concentrations (0, 5, 10, 20%) of defatted ginseng seed meal(DGSM). Specific gravity and pH of bar batters were lower in bars containing DGSM. Specific volume, loss rate and leavening rate of bars were decreased as DGSM increased. In color of bar crust and crumb, the L and bcolor values decreased according to the level of DGSM added, whereas the a color valuesand △ increased. The bars with 5, 10 and 20% DGSM had significantly higher hardness value than control bar (p < 0.05). The result of sensory evaluation showed that intensity scores for color, flavor, taste, after taste and texture were highest for the nutrition bar substituted with 20% DGSM. The nutrition bar with 10% DGSM attained the highest overall acceptability score. Results indicated that optimal concentration of DGSM into the nutrition bar was 10%.Key words : defatted ginseng seed meal, nutrition bar, quality characteristics, sensory evaluation

다시마 분말 첨가 스펀지 케이크의 품질 특성

다시마 분말을 밀가루 중량에 대해서 3%, 5%, 7%와 9%의 비율로 첨가하여 제조한 스펀지 케이크의 물리적 관능적 특성을 검토해본 결과, 다시마 분말 첨가 스펀지 케이크의 수분함량은 첨가구간의 유의적 차이는 없었으며, 조단백질 함량은 대조구가 가장 낮았고, 다시마 분말 첨가량이 증가할수록 증가하였다. 조지방 함량은 대조구와 다시마 분말 첨가구 간의 유의적 차이가 없었다. 회분 함량은 대조구가 가장 낮은데 비해 다시마 분말 첨가량이 증가할수록 유의적으로 증가한 것을 볼 수 있었다. 다시마 분말 첨가 스펀지 케이크의 탄수화물 함량은 대조구와 첨가구 간의 유의적 차이는 없었다. 비중은 대조구가 가장 낮게 나타났으며, 대조구에 비해 다시마 분말 첨가군의 비중이 유의적으로 증가하는 것으로 나타났다. 굽기 손실은 대조구가 가장 낮았고, 9% 첨가구가 가장 높게 나타났으며, 반죽 수율은 대조구가 가장 높았고, 9% 첨가구가 가장 낮았다. 다시마 첨가에 의하여 케이크의 색은 다소 어둡고 푸른색을 띄는 변화를 보였다. 밝은 정도를 나타내는 L값은 대조군이 다른 첨가군들에 비해 유의적으로 높게 평가되었고, 다시마 첨가량이 증가할수록 유의적으로 감소하여 다시마 분말 9% 첨가구가 가장 어두운 색을 나타내었다(p<0.05). 적색도를 나타내는 a값도 다시마 분말 첨가량이 증가할수록 유의적으로 증가하였다. 황색도를 나타내는 b값은 다시마 분말 첨가량이 증가함에 따라 유의적으로 감소하였다(p<0.05). 다시마 분말 첨가량에 따른 스펀지 케이크의 texture 특성으로 경도(hardness), 탄력성(springiness), 응집성(cohesiveness), 점착성(gumminess), 씹힘성(chewiness), 회복탄력성(resilience)을 검토해본 결과, 3%, 5%와 7% 첨가구는 대조구와 비교하여 그 물리적 특성이 비슷하거나 큰 차이가 없었으나, 9% 첨가구의 경우 스펀지 케이크의 texture로서 바람직하지 않은 것으로 나타났다. 스펀지 케이크의 외관은 다시마 분말 첨가량이 증가할수록 부피와 높이가 감소하였으며, 가운데 부분이 약간 주저앉은 것을 확인할 수 있었다. 스펀지 케이크의 전반적 기호도, 색, 향기, 조직감, 맛에 대한 관능적 특성을 조사한 결과, 3%와 5% 첨가구에 대한 전반적 기호도와 맛에 대한 선호도가 높은 것으로 유의성(p<0.05) 있는 결과가 나타났다. 다시마 분말 첨가 스펀지 케이크의 개발 가능성 검토를 위해 다시마 분말을 다양한 수준으로 첨가한 케이크를 제조하여 물리적 관능적 특성을 검토해본 결과, 다시마 분말 3% 첨가 스펀지 케이크와 5% 첨가 스펀지 케이크가 물리적 특성과 관능적 특성을 모두 만족시킬 수 있는 첨가량임을 확인할 수 있었다. This study was performed in order to investigate the quality characteristics of sponge cake made with Laminaria japonia powder. To evaluate the physical and sensory analysis, Laminaria japonia powder was added to wheat flour in various ratio (3, 5, 7, 9%, w/w). The specific gravity and loss rate increased with the addition of Laminaria japonia powder. The crude protein and ash levels in the sponge cakes increased linearly with the addition of 0~9 g of Laminaria japonia powder/100 g of wheat flour. For the crumb color values, lightness (L) and yellowness (b) decreased with the addition of Laminaria japonia powder, whereas redness (a) significantly increased (P<0.05). In the texture analysis, the hardness, gumminess and chewiness were increased; however, the cohesiveness and resilience were reduced by the addition of Laminaria japonia powder. When the sensory characteristics were evaluated, 5% Laminaria japonia sponge cake showed the highest sensory properties, except for color. Therefore, the results suggested that 5% Laminaria japonia sponge cake could be helpful in improving the physical quality as well as the taste.