Textural modification of soya bean/corn extrudates as affected by moisture content, screw speed and soya bean concentration

A Clextral BP‐10 (type BC45) co‐rotating twin‐screw extruder was used for texture modification of extrudates. Dry materials were mixed in a mixer for 15 min at low speed before extrusion. Moisture content 21–23% and addition of soya bean flour (0–40%) showed significant influences on the texture of the extrudates. Addition of soya bean flour in the range from 0 to 40% increased the diametrical expansion ratio (P < 0.01), decreased the hardness (P < 0.01) and modifies specific volume and chewing behaviours of the extrudates. Increasing moisture content in the range from 21 to 23%, however, significantly decreased specific volume (P < 0.01), and increases hardness (P < 0.01) of the extrudates. The hardness and crispness of the extrudates at fracturability of 110 g were graded higher than 6.0 by 30 and 27 of 34 consumer panelists, respectively. Consumer purchase intent showed the highest score of 5.5 in a 9‐point hedonic scale when sample fracturability was at 110 g.     

Structural Properties of Corn-Legume Based Extrudates as a Function of Processing Conditions and Raw Material Characteristics

The effect of extrusion conditions, including feed rate (2.52–6.84 kg/h), feed moisture content (13–19% wet basis), screw speed (150–250 rpm), and extrusion temperature (150–230°C) on structural properties of corn-legume based extrudates was studied. Four different types of legumes, chickpea, mexican bean, white bean, and lentil were used to form mixtures with corn flour in a ratio ranging from 10 to 90% (corn/legume). A simple power model was used to correlate porosity with extrusion conditions and material characteristics. The influence of feed rate in the extrudates porosity is incorporated into mean residence time. Porosity of extrudates was found to increase with temperature and residence time and to decrease with feed moisture content and corn to legume ratio. Screw speed did not affect extrudates properties. Expansion ratio showed a similar behavior with porosity. The addition of legumes (protein source) led to more dense products. Comparatively, the usage of white bean in mixtures for the production of snacks, led to a product with higher porosity than those with other legumes.     

Glass transition and water plasticization effects on crispness of a snack food extrudate

Abstract

A crispy snack model, composed of maltodextrin, wheat flour, salt, and water, with a clearly measurable glass transition was designed and produced by extrusion. The material was used to investigate effects of glass transition and water plasticization on mechanical properties and sensory crispness. Water sorption and the glass transition temperature range were determined gravimetrically and using differential scanning calorimetry (DSC) for samples stored at 0 to 85% relative humidity (RH), respectively. Mechanical properties were determined for extradates rehumidified at 0 to 76% RH. Three sensory panels evaluated crispness intensities of extrudates rehumidified at 33 to 76% RH by either breaking samples with fingers (Finger Task), biting using the incisor teeth (Bite Task), or biting and chewing (Bite‐and‐Chew Task). The extrudate was plasticized by water, as observed from a typical decrease of Tg with increasing water content. Changes in mechanical properties and loss of crispness occurred at an intermediate water activity level coinciding with the extent of plasticization depressing the Tg to below ambient temperature. The changes in mechanical properties and sensory crispness intensities with increasing water activity had sigmoid shapes following the Fermi's model. Loss of crispness as a result of water plasticization is likely to apply to a number of low‐moisture food materials, although various mechanical and sensory properties do not necessarily change in unison as the materials undergo a glass transition.     

不同加工方式对全豆蛋糕品质和营养价值的影响

采用烤箱烘烤和蒸锅蒸制2种不同加工方式分别制作全豆蛋糕,并对其感官性状和营养成分进行比较分析。结果显示:与蒸锅蒸制的全豆蛋糕相比,烤箱烘烤的全豆蛋糕感官评分更高;在营养成分方面,烘烤的蛋糕蛋白质、脂肪、碳水化合物、维生素A、维生素B2的含量以及能量均较高,但总膳食纤维和钙的含量却较低;亚麻籽油健康且稳定,可作为全豆蛋糕的烹调用油。2种加工方式各有优缺点,建议根据实际需求进行选择。     

Quality attributes and rheological properties of novel high milk protein-based extrudates made by supercritical fluid extrusion

Supercritical fluid extrusion (SCFX) process has opened up a new way of extruding heat-sensitive materials such as milk protein concentrate (MPC) into novel nutritional porous extrudates. Three formulations (30%:66.5%, 60%:36.5% and 90%:6.5% of MPC: rice flour, w/w) with 1% Dimodan, 1% lecithin and 1.5% salt were extruded by using SCFX. The physical, rheological and thermal properties of the extrudates were evaluated. The results showed that the increased MPC contents decreased gelatinisation enthalpy and increased the viscosity of the extrudates, which contributed to develop stable porous extrudates; and the increased MPC contents also helped to form a stronger gel network existed in dispersion of the extrudate samples, which resulted in a higher stress to break the gel and flow. The radial and overall expansions, crispness, porosity, rehydration ratio, moisture content and water activity increased while the axial expansion, hardness, piece density, apparent density, bulk density, decreased with higher amounts of MPC contents in extrudates. The overall results indicated that 90% MPC-containing extrudate was very suitable for developing highly nutritional and healthy cereals/snacks.     

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.     

Mechanical Properties of Corn-Legume Based Extrudates

The effect of extrusion conditions, including feed rate (2.52–6.84 kg/h), feed moisture content (13–19% wet basis), screw speed (150–250 rpm), and extrusion temperature (150–260°C) on the mechanical properties of corn/legume-based extrudates was studied. White bean and lentil were used in mixtures with corn flour at a ratio of 10:90 up to 90:10 (corn:legume). Simple power models were used to correlate breaking stress and corresponding strain with extrusion conditions and material characteristics. The influence of feed rate on the extrudates mechanical properties was incorporated in the mean residence time. The breaking stress of extrudates decreased with temperature, residence time, and corn to legume ratio, and it increased with feed moisture content. The corresponding strain showed an opposite trend. Screw speed did not affect the extrudate properties. The use of lentil flour led to a product with higher breaking stress. Furthermore, in a previous work, the porosity of these products was modeled and, now, it was found that breaking stress and porosity of the extrudates could be correlated by an exponential relationship.     

Effect of Process Conditions on the Physical and Sensory Properties of Extruded Oat-Corn Puff

ABSTRACT: The effect of processing variables, including screw speed (200,300, and 400 rpm), moisture content (18, 19.5, and 21%), and four different percentages (55,70,85, and 100%) of oat flour, on the extrudate physical properties (expansion, bulk density, and texture profiles) and sensory properties were studied. Increasing the percentage of oat flour resulted in extrudates with a lower specific length, higher bulk density, lower lightness, higher redness, lower yellowness, higher hardness, and lower springiness, gumminess, and chewiness. Higher moisture content reduced expansion, except for the 100% oat flour puffs. Screw speed had no significant effect on the bulk density, specific length, and expansion ratio. Principal Component Analysis showed that decreasing moisture content and increasing screw speed resulted in increased product temperature, which was highly correlated with attributes of a more expanded product such as lightness, crispness, shininess, and an open cell structure. With a higher screw speed and a higher product temperature, corn-related flavors were more likely to develop. High correlations between physical and sensory properties were observed.     

Corn Meal-Sunflower Meal Extrudates and Their Physicochemical Properties

Extrudates of corn meal (CM), sunflower meal (SM), and CM-SM blends at 15 (CM-SM15) and 20% (CM-SM20) protein were produced using a Wenger TX-52 twin screw extruder. Protein, starch, fiber, lipid, chlorogenic acid (CGA) and ash in CM, SM, CM-SM extrudates were the same as in unextruded material. Expansion ratios of CM, SM, and CM-SM20 were lower and that of CM-SM15 extrudate was not different from that of CM (P < 0.05). Bulk densities and shear strength of SM, CM-SM15 and 20 were higher (P < 0.05) than those of CM extrudates. Total color differences (ΔE) were observed in SM and CM-SM blended extrudates (P < 0.05). Sensory evaluation showed that crispness of SM, CM-SM15, and CM-SM20 was different from CM (P < 0.05).     

Enzyme—Pretreatment of Pinto Bean High Protein Fraction and Time of Blending Corn Meal Affects Extrudate Properties

High protein fraction of pinto bean, treated with papain and cellulose enzymes (Solvay Enzymes Inc.), was blended with corn meal (30%) and extruded at 120°C. Changes in expansion, texture, color, pH, in vitro protein digestibility, reducing sugars and functional properties of extmdates were recorded. Changes depended on type of enzymes and time of corn incorporation (before or after enzymatic pretreatment). The best texture of the extrudates was obtained using a cellulase enzyme. Papain affected some functional properties such as NSI and WSI. The best improvement in in vitro protein digestibility and reducing sugars was found with a cellulase treatment. Protein and fiber could be modified to improve physicochemical and functional properties of extrudates.     

Amylose‐lipid complex formation during extrusion cooking: effect of added lipid type and amylose level on corn‐based puffed snacks

The effect of amylose‐lipid complex formation during extrusion was studied with respect to expansion characteristics and oxidative stability of the extrudates. Full factorial design was adopted to investigate the effects of variables, amylose (two levels, 25% and 45%), types of lipid (coconut oil, fish oil and MaxEPA) and levels of lipid (1.5% and 3%), on amylose‐lipid complex formation, expansion ratio, crispness, hardness and oxidative stability. Increased amylose content in feed mixture produced crispy extrudates with significantly higher (P < 0.05) amylose‐lipid complex formation, greater radial expansion, lower hardness and higher oxidative stability. Amylose‐lipid complex formation and its complimentary effect, that is, oxidative stability were significantly higher in extrudates incorporated with coconut oil compared to those with fish oil or MaxEPA. However, better physical properties viz. radial expansion, crispness and lesser hardness were displayed by extrudates added with MaxEPA followed by those with fish oil. Between these two, fish oil‐incorporated extrudates exhibited significantly higher oxidative stability compared to MaxEPA incorporated products. Thus, the study demonstrates the usefulness of amylose rich corn flour to make oxidatively stable fish oil‐incorporated extrudates with better expansion characteristics.     

Development of protein-Rich Sorghum-Based Expanded Snacks Using Extrusion Technology

Sorghum is an important staple crop in semi-arid regions of Africa and India because of its drought tolerance. But low protein content and quality limit its widespread use. This project focused on developing sorghum-based extruded snacks. Results from preliminary lab-scale extrusion experiments were used to design a 2×5 factorial pilot-scale study. Two blends of sorghum flour and corn flour were prepared (6:1 and 5:2 w/w ratios) as the controls. Three different sources of protein—whey protein isolate, defatted soy flour, and mixed legume flour—were added to the sorghum/corn flour blends at 30%. A 50:50 blend of defatted soy flour and whey protein isolate was also added at 30% to the sorghum/corn flour blends. The resultant ten formulations were extruded on a pilot-scale twin-screw extruder to investigate the effects of sorghum/corn flour ratio and protein addition on product expansion, microstructure, mechanical properties, and sensory attributes. Expansion ratio of extruded product increased at the higher level of corn flour, and decreased with the incorporation of protein sources. Extrudates with defatted soy flour had a lower expansion ratio (5.3–5.4) than those with whey protein isolate (7.7–7.9), legume flour (7.1–9.9), or whey protein isolate-defatted soy flour (6.1–6.9). Extrudate microstructure, obtained by X-ray microtomography, corresponded well with expansion characteristics. Extrudates with defatted soy flour had the lowest cell diameter. Average crushing force (ranging from 40.9 to 154.87 N) was lower for extrudates with a higher level of corn flour. However, contrary to expectations, crushing force and crispness work both decreased with incorporation of protein sources. Consumer acceptability results showed that the addition of protein sources enhanced taste and overall acceptability of the extruded snacks, with the treatment sorghum/corn flour 5:2 and whey protein isolate-defatted soy flour as the protein source having significantly higher ratings than the other treatments.     

Physicochemical and Thermal Properties of Extruded Instant Functional Rice Porridge Powder as Affected by the Addition of Soybean or Mung Bean

Legumes contain protein, micronutrients, and bioactive compounds, which provide various health benefits. In this study, soybean or mung bean was mixed in rice flour to produce by extrusion instant functional legume‐rice porridge powder. The effects of the type and percentage (10%, 20%, or 30%, w/w) of legumes on the expansion ratio of the extrudates were first evaluated. Amino acid composition, color, and selected physicochemical (bulk density, water absorption index, and water solubility index), thermal (onset temperature, peak temperature, and transition enthalpy), and pasting (peak viscosity, trough viscosity, and final viscosity) properties of the powder were determined. The crystalline structure and formation of amylose–lipid complexes and the total phenolics content (TPC) and antioxidant activity of the powder were also measured. Soybean‐blended porridge powder exhibited higher TPC, 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power, amino acid, and fat contents than the mung bean–blended porridge powder. Incorporating either legume affected the product properties by decreasing the lightness and bulk density, while increasing the greenness and yellowness and the peak temperature and transition enthalpy. Expansion capacity of the extrudates increased with percentage of mung bean in the mixture but decreased as the percentage of soybean increased. Amylose–lipid complexes formation was confirmed by X‐ray diffraction analysis results. Addition of soybean or mung bean resulted in significant pasting property changes of the porridge powder.     

CELLULARITY, MECHANICAL FAILURE, AND TEXTURAL PERCEPTION OF CORN MEAL EXTRUDATES

Relationships among cellular structure, fracturability, and sensory properties in porous, brittle extrudates were investigated. Corn-based extrudates intentionally processed to exhibit a range of physical structures were characterized in terms of cell size distribution, bulk density, mechanical strength, fracturability, and sensory attributes. These measurements show both mechanical strength, defined by average compressive stress during extended deformation, and fracturability, quantified by fractal and Fourier analyses of stress-strain functions, increasing with either decreasing mean cell size or increasing bulk density. Fracturability parameters or structural characteristics are furthermore correlated with sensory scores for crunchiness, crispness, hardness and perceived density. These results indicate that cellularity strongly influences the pattern of mechanical failure and that failure characteristics, such as fractal dimension or power spectrum of stress-strain functions, are reflective of sensory texture.     

Feed Moisture Effects on Functional Properties, Trypsin Inhibitor and Hemagglutinating Activities of Extruded Bean High Starch Fractions

High starch fractions (HSF) of navy, pinto and garbanzo beans were extruded with different moisture contents using a Wenger X-5 extruder. Increasing moisture content resulted in increased expansion index for navy and garbanzo beans and a decrease for pinto bean. The highest water absorption index was obtained for navy bean HSF at moisture 27%, for pinto 30% and for garbanzo 26%. For all beans, water solubility index decreased with increasing moisture. Color of extrudates also was affected by moisture. The extrusion process reduced trypsin inhibitor activity by about 70–85%, the level of decrease determined by moisture content of starting material and temperature. Extrusion temperatures of 121, 132 and 150°C inactivated hemagglutinating activity of navy, pinto and garbanzo beans.     

Extrusion of Pinto Bean High Protein Fraction Pretreated with Papain and Cellulase Enzymes

High protein fraction of pinto bean was pretreated with papain and cellulase enzymes and extruded at a temperature of 120°C. The effect of enzyme type and concentration, moisture and duration of incubation on expansion, texture, color, water absorption and solubility, pH, sugars, nitrogen solubility index and in vitro protein digestibility of the extrudate were investigated. Enzymatic modification had differential effects on nitrogen and carbohydrate components and on some physical and functional preperties of extrudates, depending on type of enzyme and incubation conditions. Results indicated the possibility of controlling protein and fiber hydrolysis at low moisture to obtain a desirable degree of modification to improve extruded products. This method may be used in food applications to obtain new snack type products from beans or their fractions.     

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.     

Relationship of carrot sensory crispness with acoustic signal characteristics

The purpose of this study was to investigate the relationships of carrot sensory crispness with acoustic signal characteristics and microstructure after storage under common shelf conditions. The results showed that carrot sensory crispness declined significantly after the 14th day of storage, and the sensory score reduction was nearly up to 42% after the 28th day of storage. The carrot sensory crispness was positively related to both the waveform index (r = 0.785, P < 0.01) and sound intensity (r = 0.732, P < 0.01) of the acoustic signals in the time domain. Hilbert–Huang transform is a useful method for the observation of frequency changes in the time domain. The overall frequency bands were distributed around 200–2000 Hz through the Hilbert spectra. Rupture did not occur until the 14th day (crispness declined significantly) of storage through the scanning electron microscopy images of microstructure, and the crispness declined gradually with the increase of rupture.     

高纤维酸浆豆干制作配方优化及品质分析

本文以提高豆干副产物利用及生产高品质豆干为目的,在酸浆豆干制作工艺的基础上,添加豆渣和谷氨酰胺转氨酶(TG酶),选择豆水比例、豆渣添加量、酸浆添加量和TG酶添加量为考察因素,以感官评分为评价指标,优化高纤维酸浆豆干的制备工艺,并将其与传统酸浆豆干进行比对,分析二者的膳食纤维含量、感官评价、质构特性、蛋白质结构和微观结构...     

Sensory Optimization of Broken-Rice Based Snacks Fortified with Protein and Fiber

ABSTRACT:  A 3-component mixture experiment was used to optimize the formulation of broken-rice based snack fortified with protein and fiber based on consumer sensory acceptability. Soy protein isolate and guar gum were used as a good source of protein and fiber, respectively, according to DRV (daily reference value) based on a 2000-calorie diet. A consumer panel evaluated sensory acceptability of color, crispness, and flavor, and overall liking of 12 experimental broken-rice based snack formulations. Predicted models derived from the restricted nonintercept regression analysis were used to plot mixture response surfaces (MRS) of each sensory attribute. Areas within the MRS plots having predicted acceptability scores of at least 6.5 (on a 9-point hedonic scale) for color, crispness, flavor, and overall liking were selected to derive a predicted optimum formulation range. Flavor acceptability was a limiting factor in attaining the optimum formulation range, which consisted of 40% to 48% broken-rice flour, 8% to 16% guar gum, and 20% to 33% soy protein isolate. To verify the obtained predicted models, the formulation containing 48% broken-rice flour, 8% guar gum, and 20% soy protein isolate, which was located in the optimum area, was chosen to support our effort to utilize and add value to broken rice. Selected physicochemical measurements of the chosen optimized formulation were determined. One serving size (30 g) of the chosen optimized snack product provided 6.58 g protein and 3.80 g dietary fiber, which met the US FDA definition of a good source of protein and dietary fiber.