Triticale extrudates – Changes of macrostructure,mechanical properties and molecular water dynamics during hydration

The effect of hydration (in the range of aw 0.981–0.090) on changes of macroscopic and mechanical features of triticale snacks produced in different conditions (feed moisture - 16 and 20%; extrusion temperature - 135 and 175 °C) was analysed. Changes of snacks depended both on the hydration level and the extrusion process conditions.As a result of storage at the highest hydration level (aw = 0.981) contraction of snacks was observed. The shrinkage was more pronounced in case of extrudates obtained from raw material containing 16% of water regardless of the extrusion temperature. The hardness of extrudates depended both on the feed moisture and hydration. Samples obtained from the raw material containing 20% moisture were harder than those prepared at the feed moisture of 16%. Based on the results of molecular dynamics study by low field NMR technique, a model of hydration was developed and critical hydration value of extruded snacks was calculated. Higher values of the critical hydration were obtained for snacks extruded at temperature 135 °C than for those obtained at 175 °C. The feed moisture level affected critical hydration values to a lesser extent. Obtained results suggest that the state of water in extrudates depends on extrusion process conditions.     

Estimated Glycemic Index and Dietary Fiber Content of Cookies Elaborated with Extruded Wheat Bran

The increasing demand for high-fiber products has favored the design of numerous bakery products rich in fiber such as bread, cookies, and cakes. The objective of this study was to evaluate the dietary fiber and estimated glycemic index of cookies containing extruded wheat bran. Wheat bran was subjected to extrusion process under three temperature profiles: TP1;(60, 75, 85 and 100 °C), TP2;(60, 80, 100 and 120 °C), and TP3;(60, 80, 110 and 140 °C) and three moisture contents: (15, 23, and 31 %). Cookies were elaborated using extruded wheat bran (30 %), separated into two fractions (coarse and fine). The dietary fiber content of cookies elaborated with extruded wheat bran was higher than the controls; C0 (100 % wheat flour) and C1 (30 % of no extruded bran coarse fraction) and C2 (30 % of no extruded bran fine fraction). The higher values of dietary fiber were observed on cookies from treatments 5 (TP1, 31 % moisture content and coarse fraction) and 11 (TP2, 31 % moisture content and coarse fraction). The estimated glycemic index of cookies ranged from 68.54 to 80.16. The dietary fiber content of cookies was increased and the lowest glycemic index corresponded to the cookies elaborated with extruded wheat bran. Cookie made with the treatment 11 had a better dietary fiber content and lower estimated glycemic index.     

Quality evaluation of commercial chile-based salsas

A standardized extrusion cooking process was developed for production of a high protein weaning food based on peanuts, maize and soybeans. Major factors evaluated included the effects of blend formulation, extrusion temperature and feed moisture content on ease of extrusion and product quality characteristics. Results showed bulk density and hardness increased while expansion index decreased with increase in feed moisture content. At a fixed range of feed moisture content, product bulk density and firmness decreased while expansion index increased with increasing extrusion temperature. For ease of extrusion and best product quality in terms of sensory attributes and cooking properties, the following extrusion parameters were established for a blend formulation of 75% maize, 10% peanut and 15% soybean: feed particle size of 300–400 m extruded using a screw speed of 500 rpm, with a feed rate of 4.6 kg/min, feed moisture content of 16–18%, and extrusion temperature of 100 ,°C–105,°C. Pair-wise comparison of the sensory attributes of porridges prepared from milled samples of the weaning foods showed significant differences between extruded products and existing traditional counterparts, with very high scores for all sensory attributes of the extruded products, especially extruded raw (non-roasted) blend samples. In the Home-Use-Test, at least 92% of respondents in two out of the three major ecological zones of Ghana placed overall sensory and functional characteristics of extruded raw blend samples as highly acceptable. About 7% of respondents scored sensory and functional quality attributes as acceptable.     

Physicochemical, Structural and Textural Properties of Tortillas from Extruded Instant Corn Flour Supplemented with Various Types of Corn Lipids

The chemical composition and the components of corn grain affect the quality of tortillas produced from extruded instant corn flour (EICF). We have studied the effects of various types of corn lipids added at several concentrations to the regular raw corn flour before processing. The structural properties of flour, the effective moisture diffusion coefficient and the weight loss during cooking of fresh masa, as well as the textural characteristics of tortillas were analysed as a function of concentration and type of corn lipid added. The concentration of added lipid ranged from 0·5 to 2% (w/w). Each type and concentration of lipid was observed to have a different effect in the quality of masas and tortillas. Commercially it is desired to have tortillas with good properties and a high yield, that is, optimum weight transformation from corn to tortilla. From our analysis, the lowest dehydration rate (lowest effective moisture diffusion coefficient) and the best physicochemical and textural characteristics of fresh masas and tortillas were obtained from flour supplemented with 0·5% (w/w) of the nonpolar lipid fraction III. The loss in starch crystallinity due to the cooking process of masa into tortilla was similar in all treatments.     

Gliadin and zein show similar and improved rheological behavior when mixed with high molecular weight glutenin

Small amplitude and lubricated squeezing flow tests were performed to investigate the effect of high molecular weight glutenin (HMWG) on the rheological properties of gliadin and zein dough composites. It was hypothesized that addition of small amounts of HMWG to zein cause changes in its viscoelastic properties in the same way as its addition to gliadin. Starch (87%, w/w) and protein/protein composites (13%, w/w), and water were mixed into dough. The water content of prepared dough was in the 41.7–45.3% range. Composites were gliadin-HMWG and zein-HMWG. Phase angle and complex modulus (G*) were obtained from frequency sweep tests at 0.5% strain amplitude over a 0.01–100 rad/s frequencies. Lubricated squeezing flow test were carried out at a range of strain rates to determine the sample extensional viscosities.     

Effect of the Extrusion on Functional Properties and Mineral Dialyzability from <Emphasis Type="Italic">Phaseolus Vulgaris</Emphasis> Bean Flour

The effects of extrusion conditions on cooking degree, flour dispersion viscosity and mineral potential availability of extruded bean flour were studied. Phaseolus vulgaris beans of the agronomic cultivar “Flor de mayo” were ground and dehulled to obtain grits and then extruded at different temperatures (140, 160 and 180 °C) and moisture contents (17, 20 and 23%), according to a bifactorial experimental design. Degree of cooking was estimated by water solubility (WS) and specific mechanical energy (SME). The effect of variables on WS and SME were analysed by surface response methodology. Flour dispersion viscosity and mineral availability (estimated by in vitro dialyzability), were also evaluated on selected samples. Results showed that, within the ranges of the variables used for this study, only the effect of temperature was significant on the degree of cooking. No direct correlation was observed between water solubility and SME, although a maximum value of WS corresponded to a range of SME values of 400–500 J/g was observed. Dispersion viscosity decreases as WS increases, so if high calorie density is desired, for instance in order to produce a cream soup formula, bean grits should be extruded at high temperature and as low moisture as possible, in our case 180 °C and 17% moisture. On the other hand, the effects of extrusion variables on iron and zinc dialyzability were not much affected.     

Effect of extrusion process variables on physical and chemical properties of extruded oat products

The purpose of this research was tostudy the effects of initial moisture levels andextrusion temperatures on bulk density, waterabsorption and water solubility indexes, viscosity,and color of extruded oat products. The dehulledgrains were ground in a Brabender Quadrumat Seniormill and the coarse fraction, with higher amounts ofcrude protein, lipids, and dietary fiber content, wereconditioned to moisture levels of 15.5–25.5% andextruded in a Brabender single-screw laboratoryextruder. The water absorption index of extrudateswere relatively low (4.16–6.35 g gel/g sample) butincreased as the initial moisture of the raw materialas well as the extrusion temperature was elevated.The water solubility index was inversely proportionalto the extrusion temperature. Initial viscosity of thepaste increased with the increase of raw materialmoisture and extrusion temperature, while the maximumviscosity (at a constant temperature) diminished withthe increase of temperature. Products with lowervalues of L* (luminosity) and greater values ofa* (red) and b* (yellow) were obtained athigh moisture rates and at a 120 ^°C extrusiontemperature.     

Proximate composition and some functional properties of extrusion cooked soybean and sweet potato blends.

Mixtures of sweet potato flour and soy flour were made in a pilot mixer. They were moisturized with 18, 25, and 30% water and extruded in a single screw extruder at 80 rpm, using a die of 6mm. Extrusion temperature was maintained at 100 +/- 3 degrees C. Effects of adding soy flour into sweet potato flour, as well as variation in feed moisture on the composition and some functional properties of the extrudates were investigated. Increase in sweet potato content increased carbohydrate values. Protein increased with increase in soy flour. Feed moisture did not significantly (p < or = 0.05) affect extrudate composition. Increase in sweet potato content and feed moisture increased expansion ratio. Bulk density decreased with decrease in feed moisture, but increased with increase in soy flour. Starch content increased as sweet potato content increased. Degree of gelatinization increased with sweet potato content. Lower feed moisture enhanced gelatinization. Water absorption index (WAI) increased as sweet potato content increased. Feed moisture had a slight effect on WAI and water solubility index (WSI). Amylose increased with increase in sweet potato content. Increase in soy flour led to an increase in yellowness (b*) of extrudates.     

Moisture-dependent physical properties of jatropha seed (Jatropha curcas L.)

The study was conducted to investigate some moisture-dependent physical properties of jatropha seed namely, seed dimension, 1000 seed mass, surface area, sphericity, bulk density, true density, angle of repose and static coefficient of friction against different materials. The physical properties of jatropha seed were evaluated as a function of moisture content in the range of 4.75–19.57% d.w. The average length, width, thickness and 1000 seed mass were 18.65 mm, 11.34 mm, 8.91 mm and 741.1 g, respectively at moisture content of 4.75% d.w. The geometric mean diameter and sphericity increased from 12.32 to 12.89 mm and 0.66 to 0.67 as moisture content increased from 4.75 to 19.57% d.w., respectively. In the same moisture range, densities of the rewetted jatropha seed decreased from 492 to 419 kg m⁻³, true density increased from 679 to 767 kg m⁻³, and the corresponding porosity increased from 27.54 to 45.37%. As the moisture content increased from 4.75 to 19.57% d.w., the angle of repose and surface area were found to increase from 28.15° to 39.95° and 476.78 to 521.99 mm², respectively. The static coefficient of friction of jatropha seed increased linearly against the surfaces of three structural materials, namely plywood (44.12%), mild steel sheet (64.15%) and aluminum (68.63%) as the moisture content increased from 4.75 to 19.57% d.w.     

Proximate composition and some functional properties of extrusion cooked soybean and sweet potato blends

Mixtures of sweet potato flour and soy flour were made in a pilot mixer. They were moisturized with 18, 25, and 30% water and extruded in a single screw extruder at 80 rpm, using a die of 6mm. Extrusion temperature was maintained at 100 ± 3^°C. Effects of adding soy flour into sweet potato flour, as well as variation in feed moisture on the composition and some functional properties of the extrudates were investigated. Increase in sweet potato content increased carbohydrate values. Protein increased with increase in soy flour. Feed moisture did not significantly ( p 0.05) affect extrudate composition. Increase in sweet potato content and feed moisture increased expansion ratio. Bulk density decreased with decrease in feed moisture, but increased with increase in soy flour. Starch content increased as sweet potato content increased. Degree of gelatinization increased with sweet potato content. Lower feed moisture enhanced gelatinization. Water absorption index (WAI) increased as sweet potato content increased. Feed moisture had a slight effect on WAI and water solubility index (WSI). Amylose increased with increase in sweet potato content. Increase in soy flour led to an increase in yellowness (b^*) of extrudates.     

Temperatures and ethanol effects on the properties of extruded modified starch

Temperature and blowing agent are major factors influencing the properties of extruded foam materials. This study was conducted to determine the influence of temperature and alcohol content on selected properties and molecular weight of acetylated starch foam. Starch acetate, with degree of substitution of three, was prepared from 70% amylose corn starch and extruded with either 16 or 18% (db) ethanol in a single screw extruder at either 120 or 160°C. Unit and solid densities, specific mechanical energy, compressibility, spring index, water absorption and water solubility indices, glass transition temperature, molecular degradation and degree of substitution (DS) of the starch were measured. The samples extruded at 120°C had lower spring indices and water absorption indices (WAI), but higher compressibility and unit density than acetylated starch extruded at 160°C. The samples extruded with 16% ethanol content on a dry basis had lower spring indices and higher WSI than samples extruded with 18% alcohol. The extruded samples had lower solid density, WSI and WAI as compared to non-extruded acetylated starch. A slight decrease in the average molecular weight was recorded as a result of the extrusion processing. The samples extruded at 160°C had high spring indices and low unit densities and thus were more suitable for use as a loose-fill packaging material.     

Toxicity of Acorus calamus rhizome powder from Eastern Nepal to Sitophilus granarius (L.) and Sitophilus oryzae (L.) (Coleoptera, Curculionidae)

Powders prepared from sweetflag Acorus calamus rhizomes collected at both high (1700 m) and low (900 m) altitude in Eastern Nepal were admixed with wheat at concentrations in the range 0.05–2% w/w and the wheat infested with Sitophilus oryzae or S. granarius adults. Following a 7 day incubation, the mortality of both species was significantly lower at 20 °C than at 30 °C, and the material collected from high altitude was slightly less toxic than that from low altitude. The moisture content of the wheat (14 or 17%) and the part of the rhizome used to prepare the powder (young or mature growth) had no apparent effect on the toxicity of the preparation. Sitophilus granarius (L.) adults were more tolerant of the material than S. oryzae (L.), while the converse was true for larvae developing in treated grain. An admixture rate of approximately 2% w/w admixed rhizome powder was required to give complete kill of adults of both species following 7 days exposure at 20 °C, while a concentration of 1% w/w either prevented the emergence of adults or killed them rapidly following emergence when wheat containing eggs of either species was incubated for 7–8 weeks at 30 °C.

The β-asarone content of the rhizome powders was determined by GC-MS as 6.4 and 4.7% w/w (mature section of rhizomes collected at high and low altitudes, respectively) and 3.6 and 4.0% w/w (young sections of rhizomes collected at high and low altitudes, respectively). It is anticipated that, under field conditions and in the temperature range 20–30 °C, the initial residue of approximately 1300 mg/kg β-asarone required to disinfest wheat containing these weevil species would decline rapidly due to evaporation.     

Optimization of temperature, moisture content and inoculum size in solid state fermentation to enhance mannanase production by Aspergillus terreus SUK-1 using RSM

Optimization of three parameters, temperature (25-35 degrees C), moisture content (40% (w/v)-60% (w/v) and inoculum sizes (5% (w/v)-15% (w/v) were investigated and optimized by Response Surface Methodology (RSM) for optimal mannanase production by Aspergillus terreus SUK-1. A second order polynomial equation was fitted and the optimum condition was established. The result showed that the moisture content was a critical factor in terms of its effect on mannanase. The optimum condition for mannanase production was predicted at 42.86% (w/v) initial moisture (31 C) temperature and 5.5% (w/v) inoculum size. The predicted optimal parameter were tested in the laboratory and the mannanase activity 45.12 IU mL-1 were recorded to be closed to the predicted value (44.80 IU mL-1). Under the optimized SSF condition (31 degrees C, 42.86% moisture content (w/v) and 5.5% inoculum size (w/v)), the maximum mannanase production was to prevail about 45.12 IU mL-1 compare to before optimized (30 degrees C, 50% moisture content (w/v) and 10% inoculum size (w/v)) was only 34.42 IU mL-1.     

Glass transitions and the fracture behaviour of gluten and starches within the glassy state

Granular particles (crumbs) of gluten, wheat starch, and waxy maize starch were obtained by extrusion in a twin-screw cooker extruder and conditioned to a range of moisture contents (4–18%). The textures of the granules were assessed by a small sensory panel and the sounds produced during crushing (acoustic emission) measured. Solid, essentially amorphous, bars of gluten, wheat starch and waxy maize starch were produced by heat setting under pressure. The glass transition temperatures were measured by differential scanning calorimetry and dynamic mechanical thermal analysis, crystallinity by X-ray diffraction and the fracture behaviour examined using a three-point bend test. Heat-set gluten failed via elastic (brittle) fracture below its glass transition temperature, whereas, as the moisture content was increased, the glassy gelatinised starches underwent a brittle-ductile transition while still in the glassy state. This change in fracture mechanism explains why extruded gluten granules exhibited crispness at higher moisture contents than extruded starch granules, despite gluten having a lower glass transition temperature. The results suggest that the prediction of brittle textures (crisp, crunchy) from a knowledge of the glass transition temperature alone is not possible because bipolymers can exhibit different fracture mechanisms when in the glassy state.     

Process,structure and texture of extruded whole wheat

Whole wheat is well known by consumers as a health-providing ingredient. Nevertheless, in extruded products it leads to textures that are less favorable to consumer preference compared to its refined flour. An understanding of the effect of extrusion on whole wheat properties is therefore necessary to improve its texture. Whole wheat flour was extruded under varying conditions of water content (18 or 22%), screw speed (400 or 800 rpm) and barrel temperature (140 or 180 °C) and its physicochemical properties were measured. Changing the extrusion conditions significantly modified the volumetric expansion index (between 9.1 and 20.6) and longitudinal expansion (between 0.93 and 2.98) of the samples. Interestingly, changing the extrusion conditions did not significantly modify the sectional expansion. Increasing barrel temperature, water content or screw speed decreased the shear viscosity of the melt. This can be explained by plasticizing effects and modification of starch properties. The change in shear viscosity at the die can mostly explain the effect of process conditions on volumetric expansion of the extruded whole wheat. The stress at rupture of the extruded samples was varied between 0.49 and 1.86 MPa depending on process conditions. It was the lowest at high water content and low screw speed.     

玉米机械收获子粒破碎率与含水率关系的品种间差异

基于2012～2017年在北疆大田机械粒收条件下获取的收获质量评价数据,分析当地主栽的9个品种机械粒收过程中子粒破碎率和含水率的关系。调查范围内,不同品种收获期子粒含水率平均值分布范围为19.6%(KX9384,KWS1568)～28.2%(联创808),破碎率平均值分布范围为2.8%(新引M753)～8.5%(KWS2564),收获时品种间子粒含水率和破碎率均存在显著差异。分析显示,虽然131个样本子粒含水率(y)与破碎率(x)之间呈极显著正相关(r=0.302**),符合二次曲线(y=ax~2+bx+c)关系,但不同品种破碎率对子粒含水率的响应程度具有一定差异。在相同含水率条件下不同品种耐破碎性能存在较大差异,相应满足国标破碎率≤5%和≤8%要求适宜收获的子粒含水率范围也不同。筛选出新引M751、新引M753、KX9384、登海618和先玉335等耐破碎性能较好的品种。     

Physical Properties of Extruded Products from Three Mexican Common Beans (Phaseolus vulgaris L.) Cultivars

The physical properties of extruded products from three Mexican common bean cultivars were investigated. Common bean cultivars Flor de Mayo, Pinto Villa and Bayo Victoria from the same harvesting season (2006) were used in this work. Beans were milled and the flour was hydrated to 24, 26 and 28 g of water/100 g of dry weight. Two temperatures, 130 degrees C and 165 degrees C at the end of the extruder barrel without die, were experimented. Common bean flour extrudates were evaluated for water absorption index (WAI), water absorption capacity (WAC), oil absorption capacity (OAC), and emulsifying capacity (EC). Flor de Mayo extrudates showed the highest WAC and WAI values. Thus starch from Flor de Mayo beans showed minor restricted water availability. In all cases, the OAC of extruded products was lower than the crude bean flour. The EC for Bayo Victoria flour increased as a consequence of the extrusion process. The EC for Flor de Mayo was higher at lower temperature and lower moisture content than Pinto Villa and Bayo Victoria beans. EC behavior of Pinto Villa was similar to Bayo cultivar. These results indicate that it is possible to produce new extruded products with good physical properties from these common bean cultivars.     

Characteristics of biodegradable Mater-Bi®-starch based foams as affected by ingredient formulations

Expanded polystyrene (EPS) foams are widely used to provide protection to merchandise during shipping and handling. The disposal of EPS foams, however, causes pollution to the environment. Starch based loose fill packaging foams are commercially available to replace the EPS foams. Starch foams dissolve readily in water, and do not possess satisfactory physical and mechanical properties. To improve the functional properties and water resistance of starch foams, regular (25% amylose) and waxy corn starches blended with Mater-Bi® ZF03U (MBI) were extruded into loose-fill packaging foams using a co-rotating twin screw extruder. MBI contents of 10, 25 and 40% and starch moisture contents of 19, 22 and 25% (d.b.) were used. Waxy starch produced foam with greater radial expansion and lower unit and bulk densities than regular starch. Higher levels of MBI reduced radial expansion and increased unit and bulk densities. Foam made with regular starch had a lower water solubility index than foam made with waxy starch. The addition of MBI improved the water solubility. Higher starch moisture contents increased foam water solubility indices. Foams made from both types of starch possessed acceptable mechanical properties. Regular starch produced more rigid foams than the waxy starch as indicated by the higher compressibility values based on both single-piece and bulk samples. Moisture content affected the compressibilities. Higher moisture contents produced more rigid foams. The spring indices of bulk samples were excellent (>95%) for all MBI contents.     

Isolation of Nanocellulose from Water Hyacinth Fiber (WHF) Produced via Digester-Sonication and Its Characterization

The successful isolation and characterization of water hyacinth fiber (Eichornia crassipes) (WHF) nanocellulose is presented in this study. The novelty was in exploring a wider range of properties of highly purified samples of WHF after each stage of production in more depth. The isolation was accomplished by pulping in a digester and sonication. Morphological changes before and after treatment were demonstrated by scanning electron microscopy (SEM). The lignin and hemicellulose content decreased during chemical treatment. Transmission electron microscopy (TEM) and particle size analyzer (PSA) were used to determine the morphology of WHF after sonication for 1 h. TEM shows that the diameter and length of nanocellulose WHF were 15.61 and 147.4 nm, respectively. The crystallinity index and crystalline domain area significantly increased after chemical treatment. The highest crystallinity index was 84.87 % after an acid hydrolysis process. The increase in crystallinity leads to good thermal stability. Moisture absorption tests of WHF were carried out before and after treatment. The lowest moisture absorption was in the cellulose fiber after sonication (nanocellulose).