Feed Moisture Content Research Articles

Effect of feed composition, moisture content and extrusion temperature on extrudate characteristics of yam-corn-rice based snack food.

Blends of yam, rice and corn flour were processed in a twin-screw extruder. Effects of yam flour (10-40%), feed moisture content (12-24%) and extruder barrel temperature (100-140°C) on the characteristics of the dried extrudates was investigated using a statistical technique response surface methodology (RSM). Radial expansion ratio differed significantly (p ≤ 0.05) with change in all the independent variables. Highest expansion (3.97) was found at lowest moisture content (12%) and highest barrel temperature (140°C). Increased yam flour level decreased the expansion ratio significantly. Water absorption index (WAI) increased significantly with increase of all variables. However, water solubility index (WSI) did not change with change in yam flour percent. Hardness of extrudates that varied from 3.86 to 6.94 N was positively correlated with yam flour level and feed moisture content, however it decreased significantly (p ≤ 0.001) with increase of barrel temperature. Yam percent of 15.75 with feed moisture and barrel temperature at 12.00% and 140°C respectively gave an optimized product of high desirability (> 0.90) with optimum responses of 3.29 expansion ratio, 5.64g/g dry solid water absorption index, 30.39% water solubility index and 3.86N hardness. The predicted values registered non-significant (p < 0.10) differences from the experimental results. Further study would include the sensory properties enhancement of extruded snacks and little emphasis on the chemistry of interaction between different components.

Extruder Responses, Textural Properties and Color of Meat Analogs Made by High Moisture Soybean Residue and Soy Protein Isolate

The effect of mixture material with different levels which consisted in soybean residue, soy protein isolate and wheat gluten(0/65/35%-60/5/35%) during high-moisture extrusion, using a laboratory size co-rotating, twin screw food extruder under 50%-60% feed moisture content and 130-150 °C cooking temperature on selected extruder responses, color and textural properties of extruded products was studied. The results show that soybean residue content and feed moisture is negative correlation (r=-0.666 and -0.601) with the hardness of fibrous meat analogs. But cooking temperature has not significant correlation (P&gt;0.05) with the changes of extruder response, color or textural properties of meat analogs.

Modeling and Analyzing of Specific Mechanical Energy in Animal Feed Extrusion Process

<abstract><title><italic>Abstract.</italic></title> A new mathematical model was proposed to describe the specific mechanical energy (SME) in the animal feed extrusion process based on dimensional analysis methodology (DAM). The effects of feed moisture content (21.3% to 29.7%), screw speed (140 to 240 rpm), and extrusion temperature (133°C to 167°C) on SME were studied by response surface methodology (RSM). The dimensional model was established with experiment data. The average deviation of the model correlation was 0.66%. The sequencing of parameter sensitivities of the SME model was T₀ > T_b > P > ρ > Q > w > n. A positive correlation between extrusion temperature and SME and a negative correlation between screw speed, moisture content, and SME were found in both the dimensional model and RSM. It was found from RSM that the moisture content (p < 0.1) and screw speed (p < 0.1) had significant influences on SME, while the influence of extrusion temperature was not significant. The final predicted minimum SME was obtained at 29.7% moisture content, 140 rpm screw speed, and 133°C extrusion temperature. The predicted value of the DAM model was close to that of the RSM model at these conditions.

Effect of binders on the durability of wood pellets fabricated from Larix kaemferi C. and Liriodendron tulipifera L. sawdust

This study was conducted to investigate the effect of binders on the durability of wood pellets. Rapeseed flour (RF), coffee meal (CM), bark (BK), pine cones (PC), and lignin powder (LP) were used as binders in the fabrication of larch (LAR) and tulip tree (TUT) pellets. The tumbling-can method was used to measure the durability of the pellets. The addition of RF, CM, and LP to LAR and TUT particles produced pellets with good durability, and mixing CM or LP led to an improved higher heating value (HHV) of the pellets due to their high lignin and fat/oil contents. Durabilities of the LAR and TUT pellets increased as RF and CM contents were increased, and the addition of LP showed the most noticeable effect on increasing the durability. On the other hand, the use of BK and PC had a detrimental effect on the durability of LAR pellets. Based on the results, blending LP, CM, or RF as a binder might help to produce durable LAR and TUT pellets with an increased HHV. In addition, the selection of an optimal feed moisture content for the pellets fabricated with the binders might help in the optimization of the durability.

CHEMICAL, SENSORY, PHYSICAL AND MICROBIOLOGICAL EVALUATION OF THREE NOVEL MILK BEVERAGES FOR CHILDREN

Abstract This work was carried out to study effect substitution of corn grits with 5 % sweet potato or pumpkin grits for processing corn snacks using extrusion cooking techniques . The most favorable conditions for operator device were determined namely: feed moisture content , speed screw and extruder barrel temperature .Sensory evaluation such as color, taste, appearance, crispness and over all acceptability on the final product characteristics were studied. Three factors were identified for the operation as follows :feed moisture contents(16, 18 and 20%), screw speed(120, 140, 160rpm) and barrel temperature(130, 150 and 170 ° C) and the impact on the physicochemical properties such as bulk density (BD), expansion rate(ER) and water solubility index %( WSI %). The results indicated that the suitable expansion ratio were 2.01 and 2.62 gm/ cm3 and the swelling percentage were 3 .5 to3.4 %, respectively checks at 16% and 18% moisture for blend snacks1 ( 95% corn grits + 5% sweet potato grits )and blend snacks2 ( 95% corn grits + 5% pumpkin grits),while the proper screw speed ( 120 and 140 rpm ) by high barrel temperature ( 130 and 150 oc). The results showed significant differences in the color, taste, appearance, crispness and over all acceptability in each of the blend 1 and 2 as compared to the control (100% corn grits snacks) and had a best appearance of the blend 1 and the highest values ​​for color, taste and over all acceptability for the blend 2. So, it can be concluded that the process of extrusion device cooking heat the most suitable for operation is content feed humidity 16% ,temperature130 °c and the speed screw120rpm for a blend1 and 18% moisture ,150° c and 140rpmfor the blend 2to produce a product acceptable corn Snacks, and on the other the use of 5% of the sweet potatoes grits or pumpkin grits for the production of corn snacks contributed positively to show the desired qualities of a product such as increasing the expansion rate , improved crispness, taste and overall acceptability. This study highlights the importance of the selection experimentally the impact of new ingredients on different variables when manufacturing snacks from corn snacks. Keywords: Extrusion, Snacks, Screw Speed, Sweet Potato, Pumpkin, Corn grits and sensory.

THE EFFECT OF USING SWEET POTATO AND PUMPKIN GRITS ON PRODUCING CORN SNACKS BY EXTRUSION COOKING.

Abstract This work was carried out to study effect substitution of corn grits with 5 % sweet potato or pumpkin grits for processing corn snacks using extrusion cooking techniques . The most favorable conditions for operator device were determined namely: feed moisture content , speed screw and extruder barrel temperature .Sensory evaluation such as color, taste, appearance, crispness and over all acceptability on the final product characteristics were studied. Three factors were identified for the operation as follows :feed moisture contents(16, 18 and 20%), screw speed(120, 140, 160rpm) and barrel temperature(130, 150 and 170 ° C) and the impact on the physicochemical properties such as bulk density (BD), expansion rate(ER) and water solubility index %( WSI %). The results indicated that the suitable expansion ratio were 2.01 and 2.62 gm/ cm3 and the swelling percentage were 3 .5 to3.4 %, respectively checks at 16% and 18% moisture for blend snacks1 ( 95% corn grits + 5% sweet potato grits )and blend snacks2 ( 95% corn grits + 5% pumpkin grits),while the proper screw speed ( 120 and 140 rpm ) by high barrel temperature ( 130 and 150 oc). The results showed significant differences in the color, taste, appearance, crispness and over all acceptability in each of the blend 1 and 2 as compared to the control (100% corn grits snacks) and had a best appearance of the blend 1 and the highest values ​​for color, taste and over all acceptability for the blend 2. So, it can be concluded that the process of extrusion device cooking heat the most suitable for operation is content feed humidity 16% ,temperature130 °c and the speed screw120rpm for a blend1 and 18% moisture ,150° c and 140rpmfor the blend 2to produce a product acceptable corn Snacks, and on the other the use of 5% of the sweet potatoes grits or pumpkin grits for the production of corn snacks contributed positively to show the desired qualities of a product such as increasing the expansion rate , improved crispness, taste and overall acceptability. This study highlights the importance of the selection experimentally the impact of new ingredients on different variables when manufacturing snacks from corn snacks. Keywords: Extrusion, Snacks, Screw Speed, Sweet Potato, Pumpkin, Corn grits and sensory.

Performance analysis of RF dielectric models for density-independent estimation of moisture content in sorghum

Abstract Precise on-line and bulk-density independent monitoring of moisture content in processing grain into flour is important information to improve the milling process efficiency and to obtain a high quality final product. However, since feed moisture content is difficult to measure, it is nearly never available in the milling industry. This work addresses a reliable solution to reduce the deleterious effect of the mass flow rate on the estimation of grain sorghum moisture content, a method which is based on the high correlation between grain moisture content and two of its dielectric properties, i.e., relative permittivity e′, and loss factor e″. Thus, the object of this paper was to analyse the effectiveness of three dielectric models for estimation of sorghum moisture content at excitation frequencies in the range from 75 kHz to 5 MHz, for moisture contents from 13 to 23% w.b., and bulk densities ranging from 575 to 818 kg m− 3. Goodness of fit between experimental and predicted values of moisture content was based on the following statistical parameters: coefficient of multiple determination, standard error of calibration, worst-case error, root mean squared error, mean absolute percentage error, mean bias, fit index, and reduced chi-squared. Residual plot analysis and the principle of parsimony were also considered in the selection of the most effective dielectric model. The model based on the measurement of e′ and ln(e″) at 5 MHz gave the best predictions of sorghum moisture content for the conditions studied.

Influence of twin-screw extrusion on soluble arabinoxylans and corn fiber gum from corn fiber

The effect of feed moisture content and screw speed in the extrusion process with and without chemical pretreatment of corn fiber was investigated. Different chemical pretreatment methods (NaOH and H2 SO4 solution) were compared. The improvement of reducing sugar, soluble arabinoxylans (SAX) content and the yield of corn fiber gum was measured. A high reducing sugar content was obtained in the filtrate fraction from the extruded destarched corn fiber (EDCF) with H₂SO₄ pretreatment. Feed moisture content most effectively improved both reducing sugar and SAX content of filtrate. Increasing feed moisture content and screw speed resulted in a higher SAX content in the filtrate of the EDCF with NaOH pretreatment. The SAX content of the residual solid from the EDCF with NaOH pretreatment was higher compared to H₂SO₄ pretreated and unpretreated samples and significantly increased with decreasing feed moisture content. The screw speed did not have a major impact after enzyme hydrolysis. The yield of corn fiber gum was increased by 12% using NaOH pretreatment combined with extrusion process as compared to the destarched corn fiber. The results show the great potential of the extrusion process as an effective pretreatment for disruption the lignocelluloses of corn fiber, leading to conversion of cellulose to glucose and hemicelluloses to SAX and isolation of corn fiber gum.

수분주입량에 따른 압출성형 옥수수 섬유질의 물리화학적 특성

본 연구는 옥수수 섬유질을 수분주입량의 변화에 따라 압출성형 옥수수 섬유질과 탈전분 압출성형 옥수수 섬유질의 물리화학적 특성 변화를 측정하였다. 원료의 수분주입량은 30, 40, 50%로 조절하였으며 스크루 회전속도와 사출구 온도는 각각 200 rpm, 140℃로 고정시켜 압출성형 하였다. 일반성분 함량은 원료에 비해 감소하였으며, 수분주입량이 30%일 때 옥수수 섬유질과 탈전분 옥수수 섬유질의 불용성 식이섬유 함량은 감소하고 수용성 식이섬유 함량은 증가하였다. 압출성형 옥수수 섬유질의 비기계적 에너지, 직경팽화율, 밀도, 파괴력, 탄성계수는 수분함량이 증가할수록 감소하였고, 비길이는 증가하였다. 압출성형 옥수수 섬유질의 수분흡착지수와 환원당은 수분주입량이 증가할수록 변화가 없었으며 수분용해지수는 감소하였다. 반면에 탈전분 옥수수 섬유질의 수분흡착지수는 감소하고 수분용해지수와 환원당은 증가하였다. 수분주입량 30%일 때 유용성분의 추출이 미량 증가하는 것으로 보아 압출성형공정의 적용하여 섬유질에 포함된 유용성분의 추출이 용이할 것으로 생각된다.

Effects of Waxy Rice Moisture Content and Rate of CO2 Injection on Characteristics of Extruded Pellets and Vacuum‐Puffed Yukwa (a Korean Traditional Snack)

ABSTRACTExtrusion with CO2 injection was developed to simplify the process of producing vacuum‐puffed yukwa (rice snacks). The effects of feed moisture content and CO2 injection on the characteristics of extruded pellets (maximum viscosity and degree of gelatinization) and vacuum‐puffed yukwa (expansion ratio, bulk density, hardness, and color) were investigated. Higher feed moisture increased the size of vacuum‐puffed yukwa and the degree of gelatinization, whereas the maximum viscosity decreased. Maximum viscosity and gelatinization degree of extruded pellets were highly correlated with expansion ratio, bulk density, hardness, and color values of vacuum‐puffed yukwa. Increasing feed moisture content significantly increased expansion ratio but decreased bulk density and hardness. CO2 injection decreased bulk density and hardness of vacuum‐puffed yukwa.

The Effect of Extrusion Conditions on the Physical and Functional Properties of Millet – Bambara Groundnut Based Fura

Studies were conducted on the Extrusion of fura from pearl millet and Bambara groundnut applying the Response Surface Methodology (RSM) consisting of 15 design points, using a single screw laboratory Brabendar extruder. The effects of three extrusion variables (feed composition – percentage Bambara groundnut to pearl millet, feed moisture content and screw speed) on some physical properties (bulk density, ‘BD’ expansion ratio, ‘ER’, mass flow rate, ‘MFR’, average residence time, ‘ART’ and specific mechanical energy, ‘SME’) and some functional properties (water absorption index, ‘WAI’, water solubility index, ‘WSI’ and viscosity); of fura extrudates were evaluated using response surface method (RSM). Models were developed and appropriate statistical analysis adopted to test the adequacy of the models. Linear, quadratic and interaction regression and coefficient terms and coefficients of determinants were computed to test the adequacy of the models and response surface plots were also produced from the equation and model. The linear, quadratic and interaction terms were significant (p 0.05), however the linear and quadratic terms were significant (p<0.05). The error analysis showed that lack of fit was not significant (p<0.05) for ART. The regression models for data were significant (p<0.05) with satisfactory coefficients R2 of 0.87, 0.87 and 0.92 for ART, MFR and SME respectively indicating a good fit. The coefficients of variation (CV) were less than <10%. Extrusion conditions affected the ER significantly (p<0.05) by linear and interaction terms. The BD was influenced by only the linear term (p<0.05). The R2 were 0.82 and 0.84 for ER and BD respectively, suggesting good fit. Linear, quadratic and interaction terms affected WAI. However only linear and quadratic terms indicated influence on the WSI. The R2 were 0.93 and 0.84 for WAI and WSI respectively. The samples shows that, linear, quadratic and interaction terms influenced viscosity significantly (p<0.05) with the linear term showing more effect and the R2 was 0.88 for viscosity, The lysine content (result not shown) of extrudates tremendously increased as expected as a result of inclusion of Bambara groundnut. The essential amino acids (result not shown) were present in adequate levels if compared with the recommended values of FAO/WHO (1973).

A Case Study on Maximizing Aqua Feed Pellet Properties Using Response Surface Methodology and Genetic Algorithm

Aims: The present case study is on maximizing the aqua feed properties using response surface methodology and genetic algorithm. Study Design: Effect of extrusion process variables like screw speed, L/D ratio, barrel temperature, and feed moisture content were analyzed to maximize the aqua feed properties like water stability, true density, and expansion ratio. Place and Duration of Study: This study was carried out in the Department of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur, India. Methodology: A variable length single screw extruder was used in the study. The process variables selected were screw speed (rpm), length-to-diameter (L/D) ratio, barrel temperature (degrees C), and feed moisture content (%). The pelletized aqua feed was analyzed for physical properties like water stability (WS), true density (TD), and expansion ratio (ER). Extrusion experimental data was collected by based on central composite design. The experimental data was further analyzed using response surface methodology (RSM) and genetic algorithm (GA) for maximizing feed properties. Results: Regression equations developed for the experimental data has adequately described the effect of process variables on the physical properties with coefficient of determination values (R2) of > 0.95. RSM analysis indicated WS, ER, and TD were maximized at L/D ratiomore » of 12-13, screw speed of 60-80 rpm, feed moisture content of 30-40%, and barrel temperature of = 80 degrees C for ER and TD and > 90 degrees C for WS. Based on GA analysis, a maxium WS of 98.10% was predicted at a screw speed of 96.71 rpm, L/D radio of 13.67, barrel temperature of 96.26 degrees C, and feed moisture content of 33.55%. Maximum ER and TD of 0.99 and 1346.9 kg/m3 was also predicted at screw speed of 60.37 and 90.24 rpm, L/D ratio of 12.18 and 13.52, barrel temperature of 68.50 and 64.88 degrees C, and medium feed moisture content of 33.61 and 38.36%. Conclusion: The present data analysis indicated that WS is mainly governed by barrel temperature and feed moisture content, which might have resulted in formation of starch-protein complexes due to denaturation of protein and gelatinization of starch. Screw speed coupled with temperature and feed moisture content controlled the ER and TD values. Higher screw speeds might have reduced the viscosity of the feed dough resulting in higher TD and lower ER values. Based on RSM and GA analysis screw speed, barrel temperature and feed moisture content were the interacting process variables influencing maximum WS followed by ER and TD.« less

Structural Properties of Corn-Based Extrudates Enriched with Plant Fibers

Structural properties, such as apparent density, true density, expansion ratio, and porosity, of extruded corn grits enriched with plant fibers were measured. The effect of extrusion conditions, including feed rate (0.7–1.9 g/s), feed moisture content (13–19% wet basis), and extrusion temperature (150–230°C) on structural properties of corn-based extrudates enriched with apple and oat fibers was studied. The ratio of the two fibers to corn flour was ranging from 10 to 30% (fiber/corn). A simple power model was used to correlate porosity with extrusion conditions and material characteristics. Porosity of extrudates was found to decrease with temperature, feed moisture content and fiber to corn ratio, and to increase with feed rate for both the examined fibers. Generally, the addition of fibers led to more dense products. Comparatively, the usage of apple fiber in mixtures for the production of snacks led to a product with higher porosity than those with oat fiber.

Physicochemical properties of extrudates from white yam and bambara nut blends

Abstract This study was conducted to investigate effects of extrusion conditions on physicochemical properties of blend of yam and bambara nut flours. A blend of white yam grit (750 μm) and Bambara nut flour (500 μm) in a ratio of 4:1, respectively was extrusion cooked at varying screw speeds 50-70 r.p.m., feed moisture 12.5-17.5% (dry basis) and barrel temperatures 130-150°C. The extrusion variables employed included barrel temperature, screw speed, and feed moisture content, while the physicochemical properties of the extrudates investigated were the expansion ratio, bulk density, and trypsin inhibition activity. The results revealed that all the extrusion variables had significant effects (p&lt;0.05) on the product properties considered in this study. The expansion ratio values ranged 1.55-2.06, bulk density values ranged 0.76-0.94 g cm-3, while trypsin inhibition activities were 1.01-8.08 mg 100 g-1 sample.

제조 방법이 다른 팽화미 분말의 이화학적 특성

This study is carried out in order to develop food materials for the promotion of rice consumption. In this study, we researched the physicochemical properties of extruded rice flour (ER) and gelatinization popped rice flour (GPR) by the extrusion process and by the popped method with milled rice and brown rice. The extrusion process used a couple of screw extruders. The extrusion parameter was kept constant at a feed moisture content of 25%, barrel temperature of <TEX>$120^{\circ}C$</TEX> and screw speed of 400 rpm. GPR was prepared by batch popping machine after gelatinization of rice. In order to evaluate the physicochemical properties of ER and GPR, as well as the gelatinization rate, water soluble index (WSI), water adsorption index (WAI), DPPH radical scavenging activity and total dietary fiber content, the color value was carried out. The gelatinization rate was similar to 71.1~73.8%. Further, the results of WSI and WAI were increased at ER and GPR compared to the raw materials; ER was also higher than GPR. DPPH radical scavenging activity and total dietary fiber content showed a tendency to reduce after extrution and popping. As a result of the color value, the L value of ER decreased more than the raw materials, whereas GPR increased at a and b values.

타격기류 건조장치에 의한 하수슬러지의 건조 실증실험에 관한 연구

본 연구에서는 하수슬러지를 효율적으로 건조시킬 수 있는 방법을 연구하고자 하였다. 슬러지 건조를 위해서는 슬러지 내 대부분의 함수율을 차지하고 있는 세포 내 함유수분을 제거시키는 것이 필요한데, 이에 대한 제거 장치로서 타격기류 건조장치를 적용하였으며, 직접 하수처리장에 파일롯 플랜트를 설치하여 실증실험을 실시하여, 이에 대한 운전특성과 적용가능성을 확인하고자 하였다. 주요 운전제어 변수는 슬러지 투입속도, 체인 회전속도, 공정온도 및 투입슬러지 함수율 변화 등이다. 체인의 회전속도가 증가할수록 생성슬러지 생성수율 증가 등 장치성능이 향상되었고, 공정온도가 상승함에 따라 건조효율이 증가하는 경향을 나타내었다. 투입슬러지 함수율은 60%일 때 생성슬러지 생성수율이 최대이고 함수율도 10% 내외를 나타내어 최적 조건임을 알 수 있었다. 슬러지 투입속도는 적정 투입속도 이상으로 투입 시, 생성슬러지 생산량은 증가하지 않는 반면, 오히려 잔류량만 증가하는 현상을 초래하였다. 위와 같은 실험결과로부터 장치의 최적 운전조건은 체인 회전수 1600rpm(최대속도), 최종 배출온도 <TEX>$80^{\circ}C$</TEX>, 투입슬러지 함수율 60%, 슬러지 투입속도 60kg/h이며, 이때 장치성능은 생성슬러지 생성수율 85.5%, 함수율 11.0%, 건조효율 81.7%으로 양호한 결과를 나타내었다. Effective drying method of sewage sludge is researched in this study. To dry the sludge, chain crusher flash dryer was adopted to remove moisture content in the cell which is mostly responsible for the sludge moisture content. And Pilot plant experiment was conducted in real life sewage treatment plant to study effect and characteristics of operating conditions. Operating variables include sludge feeding rate, rotational speed of chain, process temperature and feed moisture content. As rotational speed of chain increased, product yield of sludge increased, and the performance of the testing system increased. And, as process temperature increased, the sludge drying efficiency increased. It is found that optimum feed moisture content is at 60% which shows the maximum sludge product yield and about 10 moisture content(%) of sludge product. Sludge feed rate showed optimal value, and when the sludge feed rate is exceeded, sludge product yield did not increased but the amount of residue increased. Pilot plant experiment results are as follow. The optimal condition for the rotational speed of chain 1600rpm(max. speed), final sludge discharge temperature <TEX>$80^{\circ}C$</TEX>, feed moisture content 60%, and feed rate 60kg/h. When the plant was operated at the optimal conditions, the final product showed fairly good results such as sludge product yield 85.5%, moisture content 11.0% and sludge drying efficiency 81.7%.

Effects of Extrusion Conditions on the Physicochemical Properties of Extruded Red Ginseng

The effects of variable moisture content, screw speed and barrel temperature on the physicochemical properties of red ginseng powder extrudates were investigated. The raw red ginseng powders were processed in a co-rotating intermeshing twin-screw extruder. Primary extrusion variables were feed moisture content (20 and 30%), screw speed (200 and 250 rpm) and barrel temperature (115 and 130°C). Extruded red ginseng showed higher crude saponin contents (6.72~7.18%) than raw red ginseng (5.50%). Tested extrusion conditions did not significantly affect the crude saponin content of extrudates. Increased feed moisture content resulted in increased bulk density, specific length, water absorption index (WAI), breaking strength, elastic modulus and crude protein content and decreased water solubility index (WSI) and expansion (p<0.05). Increased barrel temperature resulted in increased total sugar content, but decreased reducing sugar content in the extrudate (p<0.05). Furthermore, increased barrel temperature resulted in increased amino acid content and specific length and decreased expansion and bulk density of extrudates only at a higher feed moisture content. The physicochemical properties of extrudates were mainly dependent on the feed moisture content and barrel temperature, whereas the screw speed showed a lesser effect. These results will be used to help define optimized process conditions for controlling and predicting qualities and characteristics of extruded red ginseng.

Physicochemical properties of extruded germinated wheat and barley as modified by CO2 injection and difference extrusion conditions

SummaryGerminated wheat and barley were extruded with a pilot‐scale corotating twin‐screw extruder under different barrel temperatures (100 and 120 °C), feed moisture content (30 and 35%) and CO2 injection. The effect of germination, barrel temperature, feed moisture content and CO2 injection on physical properties, proximate composition, γ‐aminobutyric acid, β‐glucan, phytic acid and protease activity was investigated. Results indicated that the barrel temperature, moisture content and CO2 injection significantly affected water absorption index (WAI), water‐soluble solid index (WSI), specific length, expansion ratio, bulk density, mechanical properties and colour of all extruded products (P &lt; 0.05). Extrusion process significantly decreased γ‐aminobutyric acid and protease activity in extruded germinated wheat (EGW) and barley (EGB) products (with and without CO2 injection). However, extrusion process (with and without CO2 injection) increased β‐glucan in EGB and decreased phytic acid in EGW. The content of proximate composition, γ‐aminobutyric acid, β‐glucan, phytic acid and protease activity was slightly affected by CO2 injection.

Process Optimization and Characterization of Sorghum Based Extruded Product

Expanded snacks made up of corn, wheat and rice is very popular because of their texture. Sorghum is one of the important cereals, which is not so far studied well for extrusion processing. Due to presence of high amount of starch (56%-73%): sorghum could be the good candidate for manufacturing of expanded snacks. The extruded products obtained using extrusion conditions such as feed moisture content (12%-16%), die temperature (150-190 °C), screw speed (150-210 rpm) and feed rate (50-70 g min -1 ) are further characterized by analyzing bulk density, expansion ratio, water absorption index (WAI), water solubility index (WSI), textural properties, color and sensory evaluation. Increase in feed moisture content resulted in extrudates with gradual increase in density, WAI and hardness and decrease in expansion, WSI, crispness and whiteness. Higher barrel temperature reduced the extrudate expansion, bulk density and hardness and increased the WSI and crispness of the extrudates. The most acceptable product is obtained using response surface methodology (RSM).

Torrefaction of beechwood: A parametric study including heat of reaction and grindability

Torrefaction describes a thermal treatment of biomass in order to obtain a solid product with more or less coal-like properties. Therefore a mild pyrolysis in an oxygen-free atmosphere is applied. In this work beechwood was used as feedstock because of its consistent quality in commercially available chips. A parametric study was conducted with a continuously working, indirectly heated reactor having a throughput on the order of 1kgproduct/h, wherein each parameter was varied independently. The reactor temperature ranged from 270 to 300 °C, residence time from 20 to 60min, and feed moisture content from 0% to 20%. Ultimate and proximate analysis of the products as well as grindability tests have been performed. Additionally, the integral heat of reaction was determined for each test run by measurement of the heat consumption of the reactor. Mass loss of the dry solid is shown to be a good indicator of the degree of torrefaction and ultimate as well as proximate analysis show good agreement with existing literature data. Grindability in terms of HGI depends on the degree of torrefaction and reaches from difficult to grind to very easy to grind. In terms of beater wheel mills used for combined drying and milling in lignite fired power plants, grindability is poor and in general worse than that of Rhenish lignite. The heat of reaction is found to be close to the border between endo- and exothermic with a trend to more exothermic behaviour for increasing degree of torrefaction. Despite the uncertainty of the heat capacity of wood and torrefied wood above a temperature of 420K, the determined heat of reaction is found to be in the range of −199J/g (exothermic) to 148J/g (endothermic) for all tests with spans of about ±70J/g for each single test run. Besides severe torrefaction, caused by a high reactor temperature, an increased residence time is found to cause a remarkable exothermic heat of reaction.