Sensory Properties of Extruded Blends of ‘Acha’ and Soybean Flour – A Response Surface Analysis

Blends of ‘acha’ and soybean flours with moisture contents of between 15 and 35% were extruded in a single screw extruder. A response surface design (central composite nearly orthogonal) was used in the investigation with four independent variables comprising of feed moisture content (FMC), feed composition (FC), screw speed (SS) and barrel temperature (TP) combined at 5 levels. The extruded products were subjected to sensory evaluation using a 20-man panelist. The results of the study showed that maximum aroma and colour rating of extrudate blends were observed at high SS with FC playing the determinant factor. Increased feed composition and barrel temperature resulted in decreased texture rating of extrudates. Extrudates of 37.5: 62.5% (soybean: acha) had the highest sensory rating compared to other blend ratios evaluated. This indicated that acceptable extruded blends of ‘acha’ and soybean products could be obtained at 37.5% soybean addition. This is was higher than the 30% already reported in literature for cereal/legume mixes.     

Effects of Salt, Sugar and Screw Speed on Processing and Product Variables of Corn Meal Extruded with a Twin-Screw Extruder

The effects of screw speed and additives (sugar and salt) on processing and product variables of corn meal extruded with a twin-screw extruder were studied. Higher salt (0–3%) and sugar concentrations (0–4%) in the feed decreased the die pressure, % torque and specific energy. But at 6 and 8%, sugar increased the three processing parameters. Higher screw speed (250 vs 200 rpm) decreased die pressure and % torque, but increased specific energy. The addition of salt and sugar enhanced extrudate radial and axial expansions, but reduced product bulk density and breaking strength. An increase in screw speed decreased radial expansion and bulk density, but increased axial expansion and breaking strength.     

Effect of process variables on trypsin inhibitor activity (TIA), phytic acid and tannin content of extruded African breadfruit-corn-soy mixtures: A response surface analysis

Flour samples of African breadfruit, corn and defatted soybean were extruded in a Brabender single-screw extruder (DCE 330, New Jersey). Effects of process variables on trypsin inhibitor activity (TIA) and other antinutritional factors (ANFs) were verified by response surface analysis (RSA). Blending improved the protein content of the mixtures but increased the ANFs. Extrusion cooking drastically reduced TIA, phytic acid and tannin content of the extrudates by 91%, 44% and 92%, respectively. The model developed produced the highest percent variation in TIA (80%) in comparison with either phytic acid (60%) or tannin (50%). Feed composition and screw speed were the most significant (P?0.05) process variables affecting TIA. Effect of feed composition was quadratic, while that of screw speed was linear. The quadratic effects of screw speed and feed composition on tannin and phytic acid were also significant (P?0.05).     

EFFECTS OF CORN MEAL, VITAL WHEAT GLUTEN, HIGH AMYLOSE STARCH AND EXTRUSION PARAMETERS ON TECHNOLOGICAL PROPERTIES OF WHEAT-BASED EXTRUDED BREADING

A wheat‐based extruded breading was produced using a Brabender single‐screw laboratory scale extruder (model GNF 1014/2) and applied to chicken nuggets. Response surface methodology was applied to study and optimize the effects of formulation and extrusion parameters on pick up, texture, solid loss, oil absorption and adhesiveness of fried coated nuggets. An optimized extruded breading was produced at 160C, 27% moisture content, 15% vital wheat gluten, 8% high amylose starch and 30% corn meal. The product showed pick up of 29.87%, adhesiveness of 100%, texture of 166.1 g, oil absorption of 2.97% and solid losses of 0.0885 absolute. The product presented similar values of pick up and adhesiveness, better texture, lower oil absorption and higher solid loss during deep‐frying, compared with commercial breadings. Acceptance test showed that the product had better overall appearance and fairly similar texture, compared with the commercial ones.     

SINGLE-SCREW EXTRUSION OF PORK AND SOY FLOUR BLEND

This study examined the rheological properties of defatted soy flour and lean pork blend of various moisture contents extruded in a single-screw extruder and the sensory texture property of extruded meat analogs as the first step to develop commercial low-cost meat analogs that not only resemble real meats but have excellent sensory textures. Additional work was also conducted to examine the effect of moisture content of soy flour under the extrusion condition (high temperature and pressure) on the fiber structure and overall texturization of the extrudate as a result of changes in chemical bonds between soy proteins. The mixture of soy meal with ground lean pork showed significant decrease in viscosity as compared with either soy meal or ground meat alone. The best sensory texture was obtained for the pork-soy flour blend with 41. 3% moisture content at screw speed of 180 rpm under the feeding-metering-die temperature setting of 140–170–80C.     

ENERGY CONSUMPTION IN SINGLE-SCREW EXTRUSION PROCESSING OF FULL FAT AFRICAN BREADFRUIT (TRECULIA AFRICANA) BLENDS

Full fat African breadfruit, corn and defatted soy blends with moisture content range of 6.20–7.50% (wet basis) were extruded in a single‐screw Brabender laboratory extruder (DCE 330, Brabender Instruments Inc., South Hackensack, NJ) at varying independent process variables of feed composition (fc), feed moisture (fm) and screw speed. A central composite design was employed to study the effects of these variables and extrusion cooking on several quality characteristics of the center point blend, and energy input as torque and specific mechanical energy (SME). SME is relevant in that the more the energy applied, the greater the degradation of starch while torque is directly correlated with power usage. Extrusion cooking significantly (P ≤ 0.05) affected bulk density, water absorption, water solubility and nitrogen solubility indices. Torque and SME ranged from 4.00 to 8.50 N·m and 216 to 376 kJ/kg, respectively. Regression analysis of data generated of experimental data showed that fc had significant (P ≤ 0.05) quadratic effect on both energy measurements. Screw speed and fm showed significant (P ≤ 0.05) linear effects on SME while screw speed alone showed significant (P ≤ 0.05) linear effect on torque. At 160‐rpm screw speed and 85% fc, the torque value was maximum (8.50 N·m). Maximum SME value of 376.72 kJ/kg was obtained at 85% fc, 24% fm and 120‐rpm screw speed. Economically, therefore, extruded products made from blends of breadfruit, corn and soy flours will require lower extruder power usage given the fat and fm levels. Findings of this research might be useful to processors for better process control and optimal energy utilization when extruding these or related blends in a single‐screw extruder.     

挤压蒸煮对豆粕体外消化率的影响

以脱脂豆粕为原料,采用双螺杆挤压技术,研究了喂料速度、物料含水量、螺杆转速、挤压温度对蛋白质消化率的影响,在单因素试验的基础上,通过正交试验确定出了豆粕最佳的挤压工艺条件。结果表明:影响消化率的主要因素是挤压温度和物料含水量,而喂料速度与螺杆转速影响较小。豆粕挤压蒸煮的最佳工艺条件是:喂料速度0.35 kg/min、物料含水量33%、螺杆转速130 r/min、挤压温度150℃,在该工艺条件下,消化率达到95.7%,比原始豆粕消化率提高12.1%。     

PROCESSING AND PROPERTIES OF EXTRUDED FLAXSEED-CORN PUFF

The effects of flaxseed meal (0, 5, 10 and 15%) in flaxseed meal/corn meal blend and processing variables, including moisture content (16, 18 and 20%), and screw speed (200, 300 and 400 rpm), on extrudate chemical property (lignan residue) and physical properties (specific volume, hardness and color) were studied. The lignan compounds in the flaxseed and corn meals were 2.27 and 0 mg/g, respectively, before extrusion. A higher flaxseed meal level and a higher screw speed favored the retention of lignan compounds, but higher feed moisture showed the opposite effect. About 25–52% lignan compounds were lost after extrusion. Increasing flaxseed meal level, increasing feed moisture or decreasing screw speed significantly reduced the expansion and resulted in harder extrudate that was darker, more reddish and less yellow.     

双螺杆挤压机工艺参数对组织蛋白的影响

本文采用新型双螺杆食品挤压机,进行了挤压加工大豆组织蛋白和工程内制品的试验研究,获得了螺杆转速,含水量和温度对挤压过程和产品组织化质量的影响规律,研究表明,螺杆转速在80r/min,100r/min之间,含水量在38％－44％之间,大豆组织蛋白的挤压组织化质量良好,螺杆转速在60r/min,80r/min这间,含水量在60％－65％之间,工程内制品的挤压组织化质量良好,优化的机筒温度和机头温度分布为：30℃－45℃－80℃100℃－130℃－150℃－100℃。     

GELATINIZATION AND VISCOSITY BEHAVIOR OF SINGLE-SCREW EXTRUDED AFRICAN BREADFRUIT (TRECULIA AFRICANA) MIXTURES

Mixtures of African breadfruit (Treculia africana), corn and soybean were extruded in a single‐screw extruder. Feed composition (fc), feed moisture (fm) and screw speed (ss) were three process variables investigated at five level conditions. The fc was at 40:5:55, 55:5:40, 70:5:25, 85:5:10 and 100:0:0% (breadfruit, corn and soybean, respectively), fm was at 15, 18, 21, 24 and 27% while ss was at 100, 120, 140, 160 and 180 rpm level conditions using a second‐order response surface composite design. Process variable conditions that did not completely gelatinize the blends were further studied for proximate composition, energy demand and levels of gelatinization and viscosity. Crude protein significantly (P ≤ 0.05) increased from 17.52% in the control (100% breadfruit) to 34.14% in the mixture containing 40% of breadfruit. Carbohydrate reduced significantly (P ≤ 0.05) from 63.18% in the control to 40.41% in the mixture. Pellets were obtained at 15% fm while strands were produced at 21%, irrespective of other variables. The unextruded control showed an increasingly higher starch viscosity, ranging from 350 BU at peak to 365 BU on cooling to 52C than the mixtures. Soy addition increased gelatinization temperatures from 77.30 to 87.90C and from 68.80 to 78.90C in unextruded and extruded samples, respectively. Gelatinization and viscosity behavior of extrudates was most influenced at 100 rpm except where minimum fm was replicated. Specific mechanical energy for extrudate transformation ranged from 167 to 241 KJ/Kg in the mixtures while the changes in expansion ratio were not significant (P > 0.05).     

Residence Time Distribution (RTD) in a Single Screw Extrusion of African Breadfruit Mixtures

Mixtures of African breadfruit (Treculia africana Decne), corn, and defatted soybean were extruded in a single-screw Brabender laboratory extruder at process variables derived from a second-order central composite design. The variables consisted of feed composition (0–100% breadfruit, 0–55% soybean, and 0 or 5% corn); fed moisture (15–27%), and screw speed (100–180 rpm). Effects of these variables on residence time distribution were investigated using Congo red as tracer. The extrudate spent longer time in the extruder as feed moisture or screw speed was decreased from 27% to 15% or 180 to 100 rpm, respectively, thereby increasing the residence time distribution characteristics. At 70% feed composition and screw speed of 140 rpm, mean residence time ([`(t)]\overline t ) increased from 40 to 50 s, whereas extrudate total collection time (t <sub>c</sub>) increased from 65 to 70 s. At screw speed of 100–180 rpm, mean residence time ([`(t)]\overline t ) decreased from 55 to 35 s, whereas extrudate total collection time (t _c) decreased from 75 to 65 s. At 100% African breadfruit composition, these time values decreased to 35 and 70 s, respectively, at the same screw speed, indicating the significant influence of feed composition and soybean addition to the mixture on residence time distribution. Residence time distribution curves indicated an early breakthrough time of 20 s at maximum screw speed (180 rpm), minimum tail of 65 s, and a plug flow pattern of the extrudates.     

挤压膨化对脱脂花生粕组织化度的影响

以脱脂花生粕为原料,采用双螺杆挤压技术,以组织化度为考核指标,分析了组织化度随喂料速度、物料湿度、机筒温度、螺杆转速的变化规律。在单因素基础上,采用Box-Behnken设计,对脱脂花生粕挤压组织化工艺条件进行优化。结果表明,脱脂花生粕最佳工艺条件为:喂料速度0.3004kg/min,物料湿度30.8%,机筒温度142.2℃,螺杆转速155r/min。在此条件下,花生粕组织化度为1.606791。     

Use of sesame oil cake (Sesamum indicum L.) on corn expanded extrudates

In the production of oil from sesame (Sesamum indicum L.) seeds, a coproduct is obtained which is rich in protein and fiber contents. Mixtures of semi-defatted sesame cake (SDSC) (0–20%) and corn grits were processed in a single screw extruder at screw speed ranging from 324 to 387 rpm to improve the nutritional value of corn expanded extrudates. Chemical composition of raw and extruded materials, sectional expansion index (SEI), texture properties, color, paste viscosity, microstructure and sensory analysis of the extrudates were performed. The addition of SDSC increased protein, fat and ash content of corn extrudates, whereas carbohydrate content was reduced. The addition of SDSC reduced the sectional expansion of the corn extrudates and increased puncture force. SDSC–corn extrudates were darker than non-SDSC–corn extrudates. Increasing SDSC increased the number of cells similar to those of commercial corn extrudates with small cells. Sensory analysis showed 20% SDSC-corn extrudates to be acceptable and nutritional balanced. The use of SDSC on corn extrudates up to 20% is an alternative to improve nutritional value keeping good sensory characteristics.     

Twin-screw Extrusion of Corn Flour and Soy Protein Isolate (SPI) Blends: A Response Surface Analysis

The effects of feed moisture, screw speed, and barrel temperature on physical properties of extruded corn flour and soy protein isolate (SPI) blends were investigated in a co-rotating twin-screw extruder using a response surface methodology. Corn flour and SPI were mixed with a ratio of 4:1. The screw speed was set at five levels between 60 and 140 rpm, barrel temperature between 140 °C and 180 °C, and feed moisture between 18% and 38%. All physical properties of the extruded material evaluated—included expansion ratio, bulk density, breaking strength, water solubility index, rehydration ratio, and color—were significantly (p < 0.05) affected by the three process variables. Feed moisture was the most significant variable with quadratic effects on most of the physical properties. Response surface regression models were established to correlate the physical properties of the extruded product to the process variables. Understanding the effect of these variables on the product physical properties was deemed useful for the development of protein-rich extruded products.     

同向旋转双螺杆挤压机产量和膨化效果的实验研究

采用向应面法研究同向旋转双螺杆挤压机操作变量对产量的影响 ,实验研究表明喂料速度和螺杆转速对常量有著影响 ,并在获得最大产量和良好膨化效果状态下对喂料速度和螺杆转速进行了优化 ,拟合的二阶统计模型适用于生产和挤压控制设计。     

CELLULAR STRUCTURE OF PEANUT-BASED EXTRUDED SNACK PRODUCTS USING SCANNING ELECTRON MICROSCOPY

A mixture of partially defatted peanut flour (12% fat) and rice flour was extruded to produce indirectly, puffed extrudates using a corotating twin-screw extruder. Extrudates were dried to obtain half-products of 11-12% moisture content, and the half-products were expanded by deep-fat frying. The effects of three levels of peanut flour (30, 40, and 50%), screw speed (200, 300, and 400 rpm) and feed rate (4, 5, and 6 kg/h) were studied by characterizing the cellular structure of expanded snack products using Scanning Electron Microscopy (SEM). Average cell size (mm²) and the number of cells per unit area (cm²) were determined from the interior cross-section area of snack products. Those parameters were influenced mainly by the level of peanut flour followed by screw speed and feed rate. Increasing peanut flour from 40 to 50% produced less puffed final products resulting in small cell size compared to snacks of 30 - 40% peanut flour. The maximum cell size was produced in the snack products extruded with peanut flour of 30 - 40% at screw speed of 250 - 330 rpm and feed rate of 4.7 - 5.7 kg/h. While the number of cells was relatively similar regardless of screw speed and feed rate, increasing peanut flour increased the number of cells. The cell walls became thicker with increasing feed rate.     

响应面法优化低值水产蛋白组织化加工工艺

目的:以北太平洋鱿鱼加工的边角料为原料,使用双螺杆挤压机研究挤压技术在低值水产蛋白组织化加工中的应用.方法:选取物料湿度、机筒温度和螺杆转速3个因素,分析其对挤出物组织化度和咀嚼度的影响;采用三因子二次回归正交旋转组合设计,对低值水产蛋白组织化加工工艺进行优化.通过试验数据推导描述2个评价指标的二次回归模型,并对其变量进行响应面分析.结果:优化得到最佳挤压工艺条件为物料湿度40.65％、机筒温度140℃、螺杆转速25.75 Hz.挤出物组织化度与操作参数,挤出物咀嚼度与操作参数的回归拟合的相关系数R2分别为0.889和0.882.结论:拟合的统计模型可信度高,本研究结果对低值水产蛋白资源组织化技术的研究有很好的借鉴意义.     

高蛋白营养膨化粉的工艺研究

以豆粕为主要原料,与玉米、绿豆混合,利用小型单螺杆挤压膨化机进行膨化实验,研究了不同物料水分含量、模头温度、螺杆转速对产品膨化效果的影响,并对挤压膨化过程中产品的水溶性和吸水性的变化进行了研究分析。确定最佳的挤压膨化工艺参数为:模头温度140℃,水分含量为19%,螺杆转速为180r/min,经过挤压膨化后,原料的水溶性和吸水性增大。