Sectional Expansion Index Research Articles

Standardization and evaluation of RTE extruded corn-pearlmillet snacks incorporated with kidney bean or green gram flour: A comparative study

The presentstudy aimed to develop ready-to-eat extruded snacks by incorporating kidney bean flour (0-25%) or green gram flour (0-25%) in a cornpearlmillet (70:30) flour blend. All flours were tested for their compositional and nutritional parameters (crude fibre, carotenoid, phyticacid, polyphenols, iron, zinc, and total dietary fibre). Evaluation of pasting characteristics, water absorption, and dough extensibility of flours and physical (bulk density, expansion ratio, sectional expansion index, and hardness) and sensory properties of extruded snacks weredone. The addition of pulses reduced pasting values, resistance to extension, and extensibility of flour while increasing water absorptions significantly (p<0.05). Physical properties and sensory characteristics of extrudates were also significantly (p<0.05) reduced by pulses addition. However, considering nutritional aspects, kidney bean flour up to 15% or green gram flour up to 10% is recommended to be incorporated for obtaining extrudates of desirable quality. Both pulses hadsimilar effects on product quality, but the use of green gram flour is preferred over kidney bean due to its minimum anti-nutritional factors available in the resulting product.

Characterization of Second-Generation Snacks Manufactured from Andean Tubers and Tuberous Root Flours.

Andean roots, such as zanahoria blanca, achira, papa China, camote, oca, and mashua, contain high amounts of dietary fiber, vitamins, minerals, and fructo-oligosaccharides. This study aimed to demonstrate the possibility of obtaining healthy second-generation (2G) snacks (products obtained from the immediate expansion of the mixture at the exit of the extruder die) using these roots as raw materials. Corn grits were mixed with Andean root flour in a proportion of 80:20, and a Brabender laboratory extruder was used to obtain the 2G snacks. The addition of root flour increased the water content, water activity, sectional expansion index, hygroscopicity, bulk density, and water absorption index but decreased the porosity. However, all 2G snacks manufactured with Andean root flour showed better characteristics than did the control (made with corn grits) in texture (softer in the first bite and pleasant crispness) and optical properties (more intense and saturated colors). The developed snacks could be considered functional foods due to the high amount of carotenoids and phenolic compounds they exhibit after the addition of Andean root flours. The composition of raw roots, specifically the starch, fiber, and protein content, had the most impact on snack properties due to their gelatinization or denaturalization.

Unlocking the potential of pasting properties to predict extrudate characteristics of corn grits blends with high amylose corn starch, potato starch, or rice flour.

The development of new production lines of extruded ready-to-eat (RTE) snacks often results in high losses of edible food due to the trial-and-error approach in industry. Being able to predict extrudate characteristics of new formulations before having to run trials on industrial scale would be beneficial for reducing waste and having a more efficient development process. With this study, the correlation between pasting properties of seven blends of flours/starches and extrudate characteristics was investigated (100% corn grits, 25% and 50% replacement of corn grits with high amylose starch, potato starch, and rice flour). The predictive power of pasting characteristics on extrudate's moisture content, water absorption and solubility index, sectional expansion index (SEI) and hardness was studied. Results indicated the potential of predicting SEI, water solubility index (WSI), and water absorption index (WAI) of RTE-snacks. WSI and WAI were, respectively, negatively correlated with peak temperature (R2 =0.897), and positively with peak temperature and positively with trough viscosity (R2 =0.855). One can conclude that the rheometer can be a useful tool to gain insight into the characteristics of the extrudate, although further research with enlargement of the dataset is necessary to make the rheometer effectively deployable for potentially other extrudate characteristics.

Lupinus sprouts a new and potential ingredient in extrusion process: Physicochemical, nutritional and structural evaluation

The objective of this study was to determine the optimal conditions of the extrusion cooking process using ungerminated Lupinus angustifolius flour, to later develop snacks with germinated flours for 3, 5 and 7 days. The optimal conditions were 16% feed moisture, 152 °C die temperature, and 47/53% lupinus/corn starch proportion. The water absorption and solubility index, bulk density, and ΔE values increased in extrudates with 7 days sprouted flour (EG7) (4.32 g/g, 19.68%, 643.60 kg/m3, 24.13 respectively). EG7 presented the lowest values in sectional expansion index and hardness (1.69 and 50.98 N respectively). Furthermore, trypsin inhibitors were inactivated during the extrusion process, and a reduction in phytic acid content was observed in the extruded products containing germinated flours. The concentration of phenolic compounds and flavonoids were higher in the extruded products with 47/53% lupinus germinated for 3 days /corn starch proportion. Changes in the components of the secondary structure protein were observed, improving protein digestibility in extrudates with sprouted flours. The combination of processes can be an alternative for the development of a snack with improved physicochemical and nutritional properties. Industrial relevanceThe results show that sprouting and extrusion are emerging techniques in food engineering that, when combined, make it possible to obtain innovative snacks with potential benefits to human health. Lupinus sprouts are a potential ingredient that allows increasing the nutritional, physicochemical and functional properties of extruded snacks; offering an alternative of healthy plant-based snacks, given its growing demand by the consumer.

Effect of wheat dextrin on corn flour extrusion characteristics

Wheat dextrin is a modified wheat starch, classified as water-soluble. This study investigated the effect of wheat dextrin as an ingredient in corn flour blends on extrusion characteristics. Blends were prepared at 0, 10 and 20 % fibre content. DOE was used to design experiments and investigate the effects of variables selected to be studied. Feed moisture content was set at 18–25 %, temperature at 110–150 °C and specific feeding load at 0.100–0.150kg/rev. Moisture content, water absorption and solubility indices, color, sectional expansion index, density, hardness, crispiness (work (Wc) and number of spatial ruptures (Nsr)) and specific mechanical energy were evaluated. A regression model was established using response surface methodology, and processing conditions for optimal quality were generated (e.g., WSI: 96.9 %, SME: 96.9 %, final MC: 93.9 %). Wheat dextrin solubility characteristics for moisture content, WAI and WSI were inconclusive, showing a high tendency to insoluble behavior. For expansion, lightness and SME characteristics depended on processing conditions, especially temperature. Crispness was highest at low MC (18.87 %) x high fiber content (20 %) (e.g., Nsr: 1.2–1.5/mm), whereas values were the lowest at high MC (25.70 %) x low fiber content (0 %) (e.g., Nsr: 0.5–0.7/mm). Optimal conditions were set at 12 % fiber content, 19 % feed moisture content, 130 °C and a specific feeding load of 0.146 kg/rev. This study showed that it is impossible to classify wheat dextrin as acting strictly according to soluble fiber characteristics based on extrudate characteristics.

Diet production and utilization of corn fermented protein compared to traditional yeast in healthy adult cats.

The inclusion of yeast in pet food can provide health benefits and increase palatability. Corn fermented protein is a co-product from ethanol production which contains approximately 20% to 25% yeast. The objective of this study was to determine the effects of the yeast in CFP on diet production and utilization when fed to healthy adult cats. The four experimental diets included a control with 15% soybean meal (CON) and diets containing either 3.5% brewer's dried yeast (BDY), 2.5% brewer's dried yeast plus 17.5% distillers dried grains with solubles (BDY+DDGS), or 17.5% corn fermented protein (CFP). All treatments except CON were formulated to contain 3.5% yeast. Experimental diets were fed to adult cats (n = 11) in an incomplete 4 × 4 replicated Latin square design. Cats were adapted to diet for 9 d followed by a 5-d total fecal collection. Titanium dioxide (0.4%) was added to all diets as an external marker to estimate digestibility. Data were analyzed using a mixed model in SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and cat and period as random effects. Preconditioner discharge temperature was greater (P < 0.05) for CON and BDY (average, 96 °C) compared to BDY + DDGS and CFP (average, 91 °C). Extruder screw speed, die temperature, kibble toughness, and kibble hardness were greatest (P < 0.05) for CFP. The bulk density of BDY + DDGS at 392 g/L was greater (P < 0.05) than BDY and CFP (average, 342 g/L). The sectional expansion index of kibble for CFP was greater (P < 0.05) than BDY + DDGS and smaller (P < 0.05) than CON but similar to BDY. Fecal output was greatest (P < 0.05) for cats fed BDY + DDGS. Nutrient digestibility was lowest (P < 0.05) for BDY + DDGS. The concentrations of short-chain and branched-chain fatty acids in fecal samples were not altered (P > 0.05) by dietary treatment. Cats had no preference (P > 0.05) when comparing CON to BDY or BDY + DDGS. However, cats consumed significantly less CFP compared to CON. The significant differences for bulk density, fecal output, and nutrient digestibility among dietary treatments are likely due to a greater fiber effect of DDGS compared to CFP. Therefore, the yeast component in CFP may provide greater kibble expansion and nutrient utilization compared to DDGS when fed to cats.

Investigation of selected independent variables on extrusion of rice semolina with and without propeller

The influence of screws with and without propeller, as well as the independent variables of material moisture content, working screw speed, feeding screw speed and die temperature on the changes of some physical and mechanical properties during singles-screw extrusion of rice semolina was studied. The response surface methodology was used with an orthogonal central composite design. Optimum modes of operation which lead to the maximization of the mass flow rate and the sectional expansion index and the minimization of the specific mechanical energy were established. The obtained results show that the use of a propeller in single-screw extrusion leads to an increase in extruder mass flow rate, a decrease in the specific mechanical energy and an increase in the sectional expansion index.

ИНДЕКС ПОПЕРЕЧНОГО РАСШИРЕНИЯ И МИКРОСТРУКТУРНЫЕ ИЗМЕНЕНИЯ ЭКСТРУДАТОВ НА ОСНОВЕ БОБОВ В ЗАВИСИМОСТИ ОТ ПАРАМЕТРОВ ЭКСТРУЗИИ

Bean seeds, einkorn wheat, and buckwheat were ground. Semolina obtained from them was mixed in the ratio of 50:40:10 (w/w/w). Samples were mixed with distilled water to be obtained various moisture contents and extruded in a laboratory single screw extruder (Brabender 20 DN, Germany) with die diameter 3 mm. The effect of extrusion variables: moisture content (16, 19, 22, 25, 28 %), barrel temperature (120, 140, 160, 180, 200ºC), screw speed (120, 140, 160, 180, 200rpm), and screwcompression ratio (1:1, 2:1, 3:1, 4:1, 5:1) on the sectional expansion index (SEI) of the extrudates was studied using response surface methodology. The average SEI values ranged from 151 to 194 %. Statistical analysis showed that all four variables had an effect on SEI. The regression equation generated from central composite rotatable design could be used to accurately predict the studied response. The expansion of the extrudates was reflected in their microstructure.

Effect of different processing conditions to obtain expanded extruded based on cowpea

Abstract Cowpea is grown mainly in regions with a hot semi-arid climate, where other pulses do not develop satisfactorily. It is the 4th most produced pulse in the world, thus supplying the domestic and export markets. Following the trends of the food products market, a study was carried out to identify the best condition of the extrusion process, to transform these nutritious grains into quality expanded products and ready for consumption. The grains were decorticated and transformed into cotyledon flour. This flour was conditioned and the Evolum HT25 twin screw extruder feeder was adjusted to a rate of 7 kg h-1. A Box-Behnken 23 design was used, considering the following variables and levels: extrusion temperature from 100 °C to 140 °C (in the 7th to 10th zone), screw speed (300 to 700 rpm) and conditioning moisture from 12% to 16%. The temperature affected linearly and negatively (p ≤ 0.05) the sectional expansion index (2.65 to 7.64). The screw speed interfered linearly and positively (p ≤ 0.05) in the longitudinal (1.12 to 9.32) and volumetric (4.91 to 24.15) expansion index, and negatively with the water absorption index (3.05 to 3.86 g g-1). The screw speed (positive linear and negative quadratic), the moisture content (negative quadratic) and the interaction (positive) between the two interfered (p ≤ 0.05) in the water solubility index (25.89% to 33.85%). The hardness value (1.24 to 2.83 N) was affected (p ≤ 0.05) by screw speed (negative linear and positive quadratic), temperature (negative quadratic), moisture (positive quadratic), and interactions of moisture with temperature and screw speed. To obtain a hardness value close to that of commercial extrudates and high-water solubility, the maximum global desirability obtained was 0.81 for extrusion at 135.6 °C, 700 rpm and 12% moisture.

Effect of extrusion parameters on the interaction between rice starch and glutelin in the preparation of reconstituted rice

Reconstituted rice produced by extrusion has been attracted attention due to nutritional fortification and convenient production. Nevertheless, how to achieve desirable qualities and physicochemical properties of reconstituted rice nearly to natural rice by regulating extrusion process parameters is difficult. Herein, rice starch/glutelin mixture as raw material of reconstituted rice was extruded at varying extrusion conditions. Specific mechanical energy (SME) and sectional expansion index (SEI) dropped with rise in density (R2 = 0.9117 and 0.8207). Solubility was enhanced with increase in product temperature (R2 = 0.9085), color darkened and shifted to reddish and yellowish as extrusion temperature increased (R2 = 0.8577). These trends were well fitted by sigmoid models. Furthermore, SME enhanced hydrophobic and electrostatic interactions between rice starch and glutelin and caused the reduction in crystallinity and thermal stability, promoting the formation of a bi-continuous matrix of protein aggregates with rice starch. The obtained results can be applied to guide the production of reconstituted rice with desirable qualities.

Extrusion and product parameters for extruded dog diets with graded levels of whole soybeans

Increasing the fat amount of the ration during extrusion can negatively affect product density and product expansion. Ingredients, like whole soybeans (WSB), which are high in fat may increase energy density while avoiding production issues. The objective of this study was to determine the effect of WSB on extrusion and product characteristics of dry expanded dog food. Experimental diets were extruded with 0, 100, 200, and 300 g/kg, as fed WSB. The processing conditions during extrusion were kept constant across all treatments. Processing outputs, trypsin inhibitor, urease, and phytic acid concentrations were analyzed. Single degree of freedom contrasts were used for statistical analysis and significance at α = 0.05. As WSB increased, the extruder load, die pressure and temperature, and specific mechanical energy (SME) decreased linearly (P < 0.05). The bulk density of the products increased linearly (P < 0.05) while the kibble sectional expansion index (SEI) decreased linearly (P < 0.05) as WSB increased. Post-extrusion, trypsin inhibitor and urease activity decreased, but trypsin inhibitor was not eliminated. In conclusion, the increased inclusion level of WSB changed processing conditions and outputs as a result of the intrinsic and intact fat content. Increasing energy input in processing may destroy anti-nutritional factors completely when WSB are included in diets.

PSXI-1 Influence of Graded Levels of Microbially Enhanced Protein on Processing and Expansion of Extruded dog Foods

Abstract Dry expanded kibbles with ingredients that bring extra nutrition and health benefits are much better received than those which are simply an economic choice by manufacturers. Microbially enhanced protein (MEP) from soybeans, a fermented ingredient, may promote utilization. The objective of this study was to determine the influence of increasing levels of MEP on extrusion processing parameters and kibble characteristics. Four dietary treatments were evaluated which differed by level of MEP in exchange for soybean meal (15%; SBM) at 5, 10 and 15% (5MEP, 10MEP and 15MEP, respectively). The four diets were produced on a single-screw extruder with processing data and samples collected every 15 minutes. Results were analyzed as a completely randomized design by one-way ANOVA and treatment means were separated by Tukey’s test using R open-source software. Feed rate and extruder waterflow rate were not different among treatments. However, motor power, shaft speed and specific mechanical energy (SME) was least for 5MEP (P&amp;lt; 0.05, 30.1 KW, 322.5 rpm and 38.4 kW hr/ton, respectively). The SME for SBM was also less (P&amp;lt; 0.05) than 10MEP and 15 MEP (43.72, vs 47.4 and 47.0 kW hr/ton, respectively), but shaft speed did not differ among these treatments. Both kibble diameter and sectional expansion index (SEI) of 5MEP (11.9 mm and 10.0 mm2, respectively) were greater (P&amp;lt; 0.05) than SBM (11.0 mm and 7.6 mm2, respectively), 10 MEP (11.4 mm and 8.6 mm2, respectively) and 15MEP (11.5 mm and 8.9 mm2, respectively). While thickness of 5MEP was thinner (P&amp;lt; 0.05) than SBM, 10MEP and 15MEP (5.73 vs average 6.20 mm, respectively). Bulk density was greater (P&amp;lt; 0.05) for SBM than 5MEP (408.7 vs 374.0 kg/m-3, respectively), while10MEP and 15MEP (388.8 and 392.7 kg/m-3, respectively) were similar to both extremes. Addition of MEP in extruded dog diets improved expansion and reduced energy requirement, but the benefits may be less at greater inclusion levels.

Development of third generation protein rich snacks from lentil and egg powder through microwave assisted extrusion cooking

PurposeThe purpose of this study was to formulate a complete protein food from lentil flour (LF) and egg powder (EP) through microwave-assisted extrusion technology.Design/methodology/approachIn the first part of the hybrid technology, the feed proportion and extrusion conditions were optimized through design expert using central composite rotatable design. In the second part of hybrid technology, the optimized protein pellets (PP) obtained were subjected to microwave heating (MH) for 50,100, 150, 200 and 250 s.FindingsThe optimum predicted conditions for development of pellets using extrusion cooking were feed proportion (85% LF and 15% EP), barrel temperature (140°C), screw speed (340 rpm) and feed moisture content (12%). When these pellets were subjected to MH, 150 s of heating time was considered as prudential to induce desirable quality changes in PP. The increase in sectional expansion index, crispness and overall acceptability from 0.637 to 0.659, 4.51 to 6.1 and 3.27 to 3.59 with corresponding decrease in bulk density and breaking strength from 73.33 to 69.75 kg/cm3 and 6.24 to 5.13 N during 150 s of MH indicated that quality characteristics of extruded PPs were improved after MH.Practical implicationsNowadays, consumers have become more health conscious than ever, and the demand for nutritious snacks has increased many folds. However, the high protein content restricts expansion of snacks, which was overcome by subjecting extruded pellets to MH to produce third generation pellets. Furthermore, the PP has a protein content of 31.62%, which indicates that if an average person consumes 100 g of these snacks, it will suffice 60% of total recommended dietary intake (0.75 g/kg body weight/day). Lentil-based pellets expanded by use of such hybrid technology (microwave-assisted extrusion cooking) can help to provide a feasible, low cost and protein-rich diet for malnourished population besides being a value addition to lentils.Originality/valueLF in combination with EP was tested for the first time for development of nutrient dense pellets. Moreover, use of microwave-assisted extrusion cooking offers a workable and innovative technique of developing protein-rich pellets with improved physico-chemical and sensory attributes.

Effects of extrusion parameters on physical &amp; textural properties of sorghum, barley, and chickpea‐based composite extruded products

A new food formulation from cereal, millet, and pulse sources is a novel approach to prepare complete nutrition food. Sorghum, barley, and chickpea were used to prepare an extruded snack food. A twin-screw extruder was used to prepare expanded products from different blends of sorghum and barley flours with the fixed proportion of chickpea flour. The effects of feed moisture (FM), barley level (BL), barrel temperature (BT), and screw speed (SS) on the physical and textural properties of snack were studied using response surface methodology. The response variables such as sectional expansion index, water absorption index, water solubility index, hardness, and crispness were determined. All the variables were significantly affected by FM, BL, BT, and SS. The results depicted that sorghum-barley-chickpea-based extruded product was practicable with the following processing factors at their optimum values such as 12%, 25%, 176°C, and 151 rpm for FM, BL, BT, and SS, respectively. Practical applications Expanded sorghum-barley-chickpea extrudates can be obtained with the addition of barley flour up to 35%. Our results revealed that the addition of 25% barley level is better compared to others with little effect on the expansion of products.

Selected physicochemical properties and sensory acceptability as affected by addition of lecithin and calcium carbonate in extruded breakfast cereals made with silkworm pupae powder and rice flour

SummaryEffects of Lecithin (LC):Calcium carbonate (CaCO3) ratios (0.00:0.50, 0.10:0.40, 0.25:0.25, 0.40:0.10 and 0.50:0.00%w/w) on selected physicochemical properties and sensory acceptability of extruded breakfast cereals made with silkworm (Samia ricini D.) pupae powder and rice flour were investigated. The control sample was made without LC:CaCO3. Compared to the control, addition of LC significantly (P ≤ 0.05) reduced sectional expansion index, water solubility index and hardness, while increasing L*, bulk density and water absorption index of the samples. Increasing the CaCO3 level decreased bulk density while increased L*, ΔE*, sectional expansion index and crispness. The LC:CaCO3 interaction influenced aw, moisture, porosity and sensory liking, especially at 0.10:0.40%w/w which was suitable to produce the breakfast cereals. All samples had a protein content between 31.70% and 33.76% (dry basis), which made them qualified as a “high‐protein” source. The white malt–honey flavour coating increased liking scores of the finished product compared to the uncoated ones.

Effect of selected parameters on sectional expansion index and bulk density during the extrusion of chickpea instant semolina

A four-factor Response surface methodology central composite rotatable design was used to study the effect of moisture content, barrel temperature, screw speed, and feed screw speed on sectional expansion index and bulk density during extrusion of chickpea instant semolina for the purpose of instant product. The regression models for the investigated responses were highly significant (according to P-value) with satisfactory coefficients of determination (R2) 0.894 and 0.957. These results show that the predicted models for the investigated responses are adequate, indicating that the second-order polynomial model could be effectively used to represent the relationship between the selected parameters. The study showed that the expansion was influenced by moisture and temperature and it increased with increasing temperature for moisture content from 20 to 23% and after that decreased. Bulk density decreased with increasing feed moisture and barrel temperature in the extruder. The most important consequences for the science and practice resulting from the conducted research are that the resulting extrudates after grinding can be successfully used for the preparation of instant product with good characteristics, such as bulk density and sectional expansion index.

Physicochemical properties, characteristics, and consumer acceptance of whole grain sorghum expanded extrudates

The objective of this work was to study how six sorghum genotypes affected the production of whole grain expanded snacks using extrusion cooking and to evaluate their physicochemical properties, sensory characteristics, and consumer acceptance. The chemical composition and antioxidant capacity of raw flours from whole grains were evaluated. Sectional expansion index, paste viscosity, and texture (hardness and crispness) analyses as well as acceptance tests and check-all-that-apply questions were conducted on the extrudates. White pericarp sorghum extrudates presented the highest sectional expansion and sensory acceptance, and were negatively correlated to total phenolic compounds and antioxidant capacity. Sorghums with tannins had the highest antioxidant capacity but the lowest values of sensory acceptance. The combination of different sorghum genotypes could be used to produce a final product with good antioxidant capacity and acceptability. Practical applications Sorghum is the fifth most produced cereals in the world largely used for animal feed but limited in direct human consumption. It is known that it has interesting agricultural characteristics such as drought and heat resistant and also contain expressive content of bioactives linked with health benefits. As an example, tannin sorghum has the greatest values of antioxidant activity when compared with other cereals, but it was demonstrated by our work that it has low sensory acceptance; on the other hand, nontannin sorghum showed higher acceptability. By understanding the technological aspects and sensory differences of sorghum genotypes processed by extrusion cooking allow the development of sorghum ready-to-eat blend products (tannin and nontannin sorghum) with the best of both antioxidant capacity and sensory acceptance. Our results could be used by the food industry to develop novel products with improved technological and sensory characteristics that could be introduced as functional healthy food options with the advantage of being a gluten-free product.

Impact of Rapeseed Press Cake on the Rheological Properties and Expansion Dynamics of Extruded Maize Starch.

Rapeseed press cake (RPC), an oil pressing side product rich in protein and fiber, can be combined with starch and valorized into directly expanded products using extrusion technology. The mechanism of starch expansion has been studied in detail, but the impact of RPC on expansion behavior is poorly understood. However, it can be linked to rheological and physicochemical properties and is a key product quality parameter. Blends with different amounts of RPC (0, 10, 40 g/100 g) were extruded at different barrel temperatures (100, 120, 140 °C) and moisture contents (24 or 29 g/100 g). The initial, intermediate and final sectional, longitudinal and volumetric expansion indices (SEI, LEI, VEI) were monitored directly, 10 s and 24 h after die exit to measure extrudate growth and shrinkage. The viscous and elastic properties of the extruded blends were investigated in a closed cavity rheometer. Starch and blends with 10 g/100 g RPC achieved a high initial SEI followed by significant short-term shrinkage. Blends containing 40 g/100 g RPC did not show any initial expansion. With increasing RPC content, the intermediate SEI decreased, but all samples reached a similar final SEI due to time-dependent swelling of the RPC blends. With increasing RPC content, the elasticity of the starch-based extruded samples significantly increased. Our study shows that comprehensive control and understanding of expansion mechanisms can be achieved only by investigating all stages of extrudate growth and shrinkage. We also found that the closed cavity rheometer is a powerful tool to correlate the rheological properties and expansion mechanisms of biopolymers.

Juniperus waste wood as a source for obtaining pellets by single-screw extrusion method

Waste wood (biomass) is one of the most valuable and multifunctional environmental, long term resources of Earth. The aim of this paper was to study the possibilities for obtaining pellets from Juniperus. excelsa M. Bieb. biomass by a single-screw extrusion pre-treatment method. Biomass obtained after aqueous distillation of J. excelsa was used. The sample was grounded and sieved into dp ⩽ 500 μm and dp ⩽ 500 μm particle in size. The experiments were carried out on a single-screw laboratory extruder “Brabender 20 DN”. According to our results, the pellets with dp < 500 μm particle size were characterized with the following indicators: the mass flow rate (1.92 kg/h), sectional expansion index (1.03), specific mechanical energy (215.65 kJ/kg), density of the extrudates (0.44 g/cm3) and volumetric flow rate (4337.58 cm3/h). The samples obtained with dp > 500 μm particle size showed the following characteristics: the mass flow rate (1.30 kg/h), sectional expansion index (1.09), specific mechanical energy (535.23 kJ/kg), density of extrudates (0.48 g/cm3) and volumetric flow rate (2719.78 cm3/h). The biomass was a potential source for biofuel production. Pellets produced from biomass with a particle size dp > 500 μm had a higher density and sectional expansion index than those with a particle size dp ⩽ 500 μm. However, their production was more economically impractical, which is due to their lower mass and volumetric flow rate, as well as higher specific mechanical energy.

Possibilities for obtaining pellets by single-screw extrusion of biomass from black pine (Pinus nigra Arn.)

The aim of the present study was to investigate the possibilities for obtaining pellets by single-screw extrusion of black pine (Pinus nigra Arn.) biomass. Two fractions of black pine needles – 1) with dp ≥ 500 μm and bulk density ρn = 0.243 g/cm3 and 2) black pine twigs with d ≥ 500 μm and ρn = 0.297 g/cm3, were obtained. Wheat bran with dp ≥ 500 μm and bulk density ρn = 0.258 g/cm3 in a ratio of 1:1 was added to the obtained fractions. The experiments showed that getting pellets by single-screw extrusion of biomass from twigs and needles of black pine was possible when mixing them in a 1:1 ratio with wheat bran. The addition of wheat bran improved the smoothness and homogeneity of the produced pellets and increased their density. High-density pellets with a low sectional expansion index were produced during extrusion. The productivity of extruding mixtures of black pine twigs with wheat bran was 30% higher than that made from a mix of black pine needles and wheat bran. The pellets obtained after mixing biomass from black pine and wheat bran had over 13% higher density than those produced entirely from wheat bran. The presence of black pine biomass increased the quality of the final product while at the same time having a positive effect on both productivity and specific energy consumption.