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

Investigating extrusion impact on functional, textural properties, morphological structure, and molecular interactions in hulless barley-based extruded snacks supplemented with mung bean

The effect of varying extrusion conditions on the functional properties of hulless barley-mung bean (70:30) extruded snacks was investigated using response surface methodology with feed moisture (FM), barrel temperature (BT), and screw speed (SS) as process variables. Results revealed significant impacts on functional characteristics with varying extrusion conditions. Bulk density (BD) of extruded snacks ranged from 0.24 to 0.42 g/cm3, showing that lower FM and higher BT results in lower BD while it increased with increasing FM, SS, and BT. The expansion ratio (ER) of extruded snacks ranged between 2.03 and 2.33, showing BT and SS had a desirable positive effect, whereas increasing FM led to decreased ER. Increasing BT and SS depicted a negative effect on water absorption index, whereas FM showed positive effect, which ranged between 4.21 and 4.82 g/g. A positive effect on water solubility index was depicted by BT and SS, which ranges between 9.01% and 13.45%, as higher SS and BT led to starch degradation and increased solubility suggesting better digestibility. The hardness of extruded snacks ranged from 32.56 to 66.88 Newton (N), showing increasing FM increased hardness, whereas higher SS and BT resulted in lowering the hardness. Scanning electronic microscope (SEM) analysis revealed structural changes in extrudates in comparison with nonextruded flour, indicating starch gelatinization and pore formation affected by varying processing parameters. Shifts in absorption bands were observed in Fourier transform infrared spectroscopy (FT-IR), suggesting structural changes in starch and protein. Understanding the effects of extrusion parameters on product properties can help tailored production to meet consumers' preferences and the development of functional snacks with improved nutritional quality.

Optimization of the extrusion parameters for the production of lentil-quinoa extrudates enriched with pumpkin

This study aimed to develop a protein-fiber-rich extruded product based on yellow lentil, quinoa, and pumpkin flours. The final product quality is affected by formulation and extrusion parameters. Therefore, the effect of the pumpkin-flour ratio (A: 25-75%) and feed moisture content (C: 14-22%) besides barrel screw speed (B: 120-180 rpm) on the physical attributes of extrudates was investigated. Box-Behnken experimental design and stepwise-response surface method were used to analyze the effects of various process variables and ingredients on extrudates. The pumpkin-flour ratio had a significant positive correlation with bulk density (BD), water solubility index (WSI), and oil absorption index. Whereas the correlation between pumpkin-flour ratio with hardness, porosity, expansion ratio (ER), and water absorption index (WAI) was negative (P < 0.05). The feed moisture content positively affected the water activity (aw) and WAI and negatively affected the harness of samples (P < 0.05). The screw speed had a positive effect on ER, porosity, and WSI, whereas it negatively influenced the hardness, BD, and aw. By increasing the pumpkin-flour ratio, air cell size and wall thickness of samples had been decreased. The results showed that 44.2% pumpkin flour, 22% feed moisture, and 172.1 rpm screw speed gave an optimized product. There was no significant difference between predicted and experimental values (except for ER). The optimized snack was a good source of fiber (around 15%), protein (17.3%), and antioxidants (TPC = 15.28 mg GAE.g-1 and antiradical scavenging activity (DPPH) = 33.66%). The caloric value of the optimized snack was 362.6 cal.100g-1. The current formulation can be considered as the base of snack food or plant-based meat alternatives.

Effect of extrusion processing on techno-functional properties, textural properties, antioxidant activities, in vitro nutrient digestibility and glycemic index of sorghum-chickpea-based extruded snacks

Physico-chemical, textural, functional, and nutritional properties of the twin screw extruded whole sorghum-chickpea (8:2) snacks was investigated using in vitro procedures. The extruded snacks were analyzed for the effect of variations in extruded conditions on their properties: barrel BT (BT) (130-170°C) and feed moisture (FM) (14%-18%), keeping screw speed constant (400 rpm). The results revealed that specific mechanical energy (SME) decreased (74.4-60.0) in response to rise in both BT and FM, whereas expansion ratio (ER) had shown an alternative relation as it decreased with elevated FM (2.17 at 14%, 130°C to 2.14 at 16%, 130°C) and increased with BT (1.75 at 18%, 130°C to 2.48 at 18%, 170°C). The values of WAI and WSI improved with the surge in BT, which was associated with enhanced disruption of starch granules at higher BT. Raise in FM incremented the total phenolic content (TPC) and hence the antioxidant activity (AA) (FRAP and DPPH) along with the hardness of snacks. As per in vitro starch digestibility is concerned, slowly digestible starch (SDS) content as well as glycemic index (51-53) of the extrudates depressed with increasing BT and FM. Also, lower BT and FM improved the functional properties such as expansion ratio, in-vitro protein digestibility, and overall acceptability of the snacks. A positive correlation was seen among SME and hardness of the snacks, WSI and ER, TPC and AA, SDS and Exp-GI, color and OA, texture and OA.

Soybean residue (okara) modified by extrusion with different moisture contents: Physical, chemical, and techno-functional properties

To increase hydration properties and soluble fiber content, okara with different moisture contents (30, 35, and 40%) was extruded in single-screw equipment, keeping the temperature (120 °C) and screw speed (115 rpm) fixed. The physical, chemical, and techno-functional properties of extruded and non-extruded okara (control) were evaluated. The microstructure, color, chemical composition, and techno-functional properties of okara were altered after extrusion. The extruded samples showed general microstructure aspects similar between them, with an irregular and rough surface, striated parts, orifices, and some agglomerated particles with distorted, compact, and amorphous appearance, different from control. Among the modified samples, okara extruded with 30% moisture showed more intense changes in relation to the samples extruded with 35 and 40% moisture. Based on the results, it can be inferred that okara extruded with 35% moisture is the most suitable. Under this condition, there was an increase of 80% in soluble fiber content, 45% in water absorption and holding capacity and 11% in solid stability in water, the maintenance of swelling and oil absorption and holding capacities and the reduction of protein solubility in water. X-ray diffraction analysis showed that crystalline phase was affected by extrusion.

Third-Generation Snacks Manufactured from Andean Tubers and Tuberous Root Flours: Microwave Expansion Kinetics and Characterization

Andean tubers and tuberous roots have nutritional and medicinal properties transferred through ancestral generations. In this study, we aim to promote cultivation and consumption by developing a snack based on these crops. Corn grits were thoroughly mixed with sweet potato, mashua, and three varieties of oca flour (white, yellow, and red) in an 80:20 ratio, and a single-screw laboratory extruder was utilized to produce third-generation (3G) dried pellets. Microwave expansion was studied, and the dried 3G pellets and expanded snacks were characterized. The microwave expansion curves of the dried 3G pellets were adjusted to the Page, logarithmic, and Midilli-Kucuk models. During the characterization, the influence of the raw material composition was observed in sectional expansion, water content, water activity, water absorption, water solubility, swelling, optical and textural properties, and bioactive compounds. According to global color variation (mixture vs. expanded and dried vs. expanded) and bioactive compound analysis, the mashua suffered little chemical change or nutritional loss during the process. The extrusion process was shown to be an ideal method for manufacturing snacks from Andean tuber flours.

Development, Characterization and Sensory Evaluation of an Extruded Snack Using Fig Molasses By-Product and Corn Semolina

The effects of extrusion process parameters on the physicochemical, pasting and technological properties of ready-to-eat snacks were evaluated. The aim was to develop fortified extruded products with fig molasses by-product powder (FMP), which is created as a result of the production of fig molasses, is not currently used in food industry, and may cause environmental problems. The feed humidity was changed to 14-17-20%, the die temperature was 140-160-180 °C and the ratio of FMP was 0-7-14% at a fixed screw speed of 325 rpm. The study showed that adding FMP to extruded products had a significant effect on colour properties, water solubility and water absorption index properties. İncreasing the FMP ratio had a significant reducing effect on dough properties of non-extruded mixtures such as peak viscosity (PV), final viscosity (FV) and setback viscosity (SB). The optimum conditions for the production of snacks were found to be 7% FMP, 155.44 °C die temperature and 14.69% humidity. It was determined that the estimated values of water absorption index (WAI) and water solubility index (WSI) for the products manufactured under ideal extrusion conditions were close to the obtained values, and that there was no significant difference between the estimated values of the other response variables and their actual values.

Food extrusion: An advanced process for innovation and novel product development

Extrusion is a versatile process capable of producing a variety of new and novel foods and ingredients, thus increasing manufacturing opportunities. Further, it could provide nutritious, safe, sustainable, and affordable foods, especially directed at individualized consumer needs. In addition to past research efforts, more investigations should be conducted in order to refine, redesign, or develop new extrusion processing technologies. The present review highlights the current advances made in new and novel food product development by considering the extrusion process, the influencing parameters, and product characteristics and properties; the most promising extrusion processes that can be used in novel food product and ingredient development, such as extrusion cooking, hot-melt extrusion, reactive extrusion, and extrusion-based 3D printing; the possibilities of using various raw materials in relation to process and product development; and the needs for product development modeling along with extrusion process design and modeling. In correlation with extruded product development, topics that merit further investigation may include structure formation, plant and animal biopolymers functionalization, biopolymer reactions, process simulation, modeling and control, engineering and mechanical aspects of extruders, analysis of pre-processing treatments, as well as prototyping, risk analysis, safety, sensory and consumer acceptance.

Development of a Novel Rice-Based Snack Enriched with Chicory Root: Physicochemical and Sensory Properties

A novel rice-based snack enriched with chicory root flour (CRF) was developed by twin-screw extrusion. Chicory (Cichorium intybus L.) is one of the promising medicinal plants for the development of innovative food and may be considered a functional food ingredient. Central composite design (CCD) was employed to generate snack formulations by varying feed moisture (M, 16.3–22.5%), screw speed (SS, 500–900 rpm) and CRF content (20–40%). The optimization according to artificial neural network modeling and a genetic algorithm was applied to define optimal process conditions (17.6% moisture, 820 rpm and 24.1% of CRF) for obtaining the product with the highest expansion (3.34), crispiness (3.22 × 10−3), volume (2040 m3), degree of gelatinization (69.70%) and good color properties. Bulk density (110.33 g/L), density (250 kg/m3), and hardness (98.74 N) resulted in low values for the optimal sample. The descriptive sensory analysis evaluated low hardness and bitterness, with high crispiness for the optimal extrudate. This study points to the possibility of a novel chicory enriched extrudate production with desirable physicochemical and sensory properties.

Effects of food hydrocolloids on quality attributes of extruded red Jasmine rice noodle

The aim of this study was to examine the quality characteristics of extruded red Jasmine rice flour (RJF) noodle that had been prepared with hydrocolloids, namely guar gum (GG), carboxymethyl cellulose (CMC), and xanthan gum (XG) at the concentrations of 0.0 (control sample), 0.2, and 0.4% (w/w), respectively. The use of hydrocolloids had no effect on total phenolic contents, antioxidant properties (DPPH, ABTS, and FRAP), color, and X-ray diffraction patterns (p > 0.05). In contrast, the hydrocolloids tended to increase the expansion ration of the noodle. GG and CMC improved cooking, textural, and sensory properties. Ultimately, 0.2%-GG showed the lowest cooking loss (5.07%) when compared with others. Moreover, it also provided the noodle with better textural properties such as tensile strength, extensibility, hardness, cohesiveness, and chewiness (p < 0.05). For these reasons, the highest acceptability (6.75) for the noodle was achieved with GG02. XG resulted in lower overall acceptability (5.05), particularly the 0.4%-XG recipe (p < 0.05). Thus, usage of 0.2%-GG was the best option for improving the qualities of extruded RJF noodle. XG was deemed ineffective for improving the noodle.

Effect of chickpea and spinach on extrusion behavior of corn grit

The present work was carried out to see the effect of blending of corn grit (CG) with varying levels of chickpea grit (CP 0-100%) and spinach leaf powder (SP 0-6%) on the characteristics [color, expansion, density, hardness, water absorption index, total phenolic content (TPC), antioxidant activity (AOA; as DPPH and ABTS free radical scavenging activities)] and sensory properties of extrudates. CP and SP were rich in proteins and minerals (Cu, Fe, Zn, Mg, Ca, K and Na). Their blending significantly influenced the physicochemical and antioxidant properties of CG extrudates. TPC and AOA of extrudates increased with the increased incorporation of CP and SP, though specific mechanical energy and extrudate expansion, generally, decreased while density and hardness increased. Sensory analysis revealed that CP and SP at incorporation levels of 25% and 4%, respectively could be blended with CG for making highly acceptable antioxidant-rich expanded snack.

Extrusion of a Curcuminoid-Enriched Oat Fiber-Corn-Based Snack Product

Extruded snack products were made from an oat fiber-corn flour matrix fortified with 1.5% (w/w) curcuminoids (750 mg curcuminoids/100 g) to improve the solubility and stability of curcuminoids. The effects of extruder feed moisture content (21%, 28%, and 35%) and screw speed (200 and 300 rpm) on the extrusion parameters and physical properties of final snacks were investigated. Curcuminoids lost during extrusion and curcuminoids loss during subsequent drying of extrudates were analyzed, to separate the losses occurring in each unit process. Drying post extrusion (at 50 °C for 4 hr) was essential to obtain a crunchy shelf stable product (5% moisture). Curcuminoids loss during extrusion was from 17% to 84%, with high loss for the extrusion with low feed moisture content (21%). A further curcuminoids loss of 4% to 44% occurred during drying, with much higher loss for the extrudate with high moisture content. Total curcuminoids retained after extrusion and drying was 12% to 41% (59% to 88% loss), equivalent to 180 to 616 mg curcuminoids retained per 100 g snack, levels within recommended daily dose. Curcuminoids retained after drying was stable during 80 days of storage at 25 °C. The results highlighted the importance of understanding the impact of each unit process separately (for example, extrusion and drying) on the stability of curcuminoids for the development of healthier extruded snacks. PRACTICAL APPLICATION: Extruded snacks products were developed by fortifying the snacks with oat fiber and curcuminoids in order to address the need for a healthy ready to eat food products. Some extrusion characteristics were selected to produce snack products which have favorable properties in terms of consumer acceptance.

Effect of extrusion temperature and screw speed on properties of oat and rice flour extrudates

BACKGROUND

Whole oat and rice flours were mixed to develop instant flours by a high pressure and low mechanical shear extrusion process. The screw profile was designed aiming to obtain an infant food with gelatinized starch and high hydration ability. Response surface methodology was selected to study the impact of operating parameters such as temperature and screw speed (73-186 °C; 109-391 rpm) on physicochemical and pasting properties of the final extruded product. The main challenge of this study was to process high oats content, since they are characterized by high lipid and fiber content, which impact on material processing.

RESULTS

The optimal response was achieved at 170 °C and 350 rpm. The optimal expansion ratio, bulk density, water absorption index, and water solubility index were 2.24, 289.65 kg m^-3 , 6.42 g g^-1 , and 4.75 g g^-1 respectively. Overall, both temperature and screw speed affected the responses studied, except for water absorption index (only screw speed affected this response). Although lipids from oats reduce the expansion ratio of extrudates compared with samples containing higher starch proportions, their lipids protect the starch granules from mechanical degradation when higher screw speed values are used. As a result, both ungelatinized and gelatinized starches may be found in extrudates, which was confirmed by pasting property analyses.

CONCLUSION

High oat content may be efficiently processed by optimizing the extruder conditions (temperature, screw speed, and profile), improving the nutritional properties of the final product. © 2017 Society of Chemical Industry.

Influence of process parameters on physical properties and specific mechanical energy of healthy mushroom-rice snacks and optimization of extrusion process parameters using response surface methodology

Ready-to-eat healthy mushroom-rice snacks were developed and processed using twin-screw extruder. A 15% of oyster mushroom power could be added to improve the nutritional values of the rice based snack. The effects of process parameters (feed moisture, screw speed and barrel temperature) on physical properties and Specific Mechanical Energy (SME) during the production were investigated. Feed moisture was varied at 12-18% wet basis and the screw speed was studied in the range of 275-425 rpm, while the barrel temperature was operated at 130-150 °C. The result indicated that bulk density differed significantly with changes in all the process parameters. An increasing barrel temperature caused higher expansion ratio, while hardness of snacks increased due to an increase of feed moisture and a decrease of screw speed. SME was considered by measuring the electric current and voltage of the extruder. As a result, feed moisture demonstrated the most influence on the SME. Feed moisture between 12 and 15% wet basis, the SME decreased with decrease in feed moisture. On the other hand, the SME decreased when the higher feed moisture was operated in the range of 15-18% wet basis. In addition, the process condition was optimized using response surface methodology. From this study, the optimum extrusion-cooking conditions with respect to the physical qualities of snacks and SME during extrusion was 13.5% of feed moisture, screw speed of 425 rpm and maximum barrel temperature at 130 °C, since these conditions provided a good quality mushroom-rice snacks and consumed low SME.

Enrichment of rice-based extrudates with Cactus Opuntia dillenii seed powder: a novel source of fiber and antioxidants

The present study investigated the effects of adding the powder of cactus Opuntia dillenii (O. dillenii) seeds on the functional properties, fiber, antioxidants and acceptability of rice-based extrudates. The control blend consisting basically of rice flour was replaced with O. dillenii seed powder at 2, 4, 6, 8, 10, 15 and 20% then extruded at the optimum processing conditions. The extruded products were evaluated for their chemical composition, functional properties, color attributes, antioxidant activity and sensory characteristics. The results revealed that adding O. dillenii seeds powder enhanced the fiber, phenolics, flavonoid contents and antioxidant activity of extrudates. Expansion, bulk density and breaking strength were significantly decreased, while water absorption index, water solubility index and oil absorption index were significantly increased compared to the control. Furthermore, the mean scores of sensory evaluation indicated clear improvements in all tested sensory attributes, which significantly increased by increasing the level of O. dillenii seed powder up to 15%. The results confirmed that O. dillenii seed powder could be incorporated in rice to develop snack products of acceptable functional, nutritional and sensory properties.

Chemical composition and physicochemical properties of Phaeodactylum tricornutum microalgal residual biomass

The production of photosynthetic biofuels using microalgae is a promising strategy to combat the use of non-renewable energy sources. The microalgae residual biomass is a waste by-product of biofuel production; however, it could prove to have utility in the development of sustainable nutraceuticals and functional foods. In this study, a comprehensive characterisation of the under-utilised Phaeodactylum tricornutum microalgae residual biomass is presented. Proximal composition, antioxidant capacity (using three different antioxidant assays; oxygen radical absorbance capacity; radical cation activity, ABTS; and radical scavenging activity, DPPH), and total phenolic content of free and bound polyphenols were determined. Additionally, the physicochemical properties of water activity, pH, water absorption index, water solubility index, and dispersibility were evaluated. Results revealed that P. tricornutum microalgae residual biomass exhibits a relatively high protein and carbohydrate content, with values of 36.67% and 46.78%, respectively; and most carbohydrates were found as total dietary fibre (45.57%), of which insoluble dietary fibre was the most predominant (43.54%). Antioxidant capacity values for total phytochemicals of 106.22, 67.93, 9.54 µM TE g^-1 dw were determined by oxygen radical absorbance capacity, ABTS, and DPPH assays, respectively. Total phenolic content was found to be 2.90 mg GAE g^-1 dw. Interestingly, antioxidant capacity and total phenolic content were higher in bound than in free phytochemical extracts. The physicochemical analysis showed P. tricornutum microalgae residual biomass to have suitable properties for the generation of a beverage with Aw, pH, water absorption index, water solubility index, and dispersibility values of 0.45, 7.12, 3.40 g gel g^-1 dw, 2.5 g solids 100 g^-1 dw, and 90%, respectively. Hence, P. tricornutum microalgae residual biomass could be considered a potential source of bioactive compounds suitable for the production of functional food exhibiting antioxidant capacity and high dietary fibre content.

Defatted flaxseed meal incorporated corn-rice flour blend based extruded product by response surface methodology

Considering the evidence of flaxseed and its defatted flaxseed meal (DFM) for human health benefits, response surface methodology (RSM) based on three level four factor central composite rotatable design (CCRD) was employed for the development of DFM incorporated corn - rice flour blend based extruded snack. The effect of DFM fortification (7.5-20 %), moisture content of feed (14-20 %, wb), extruder barrel temperature (115-135 °C) and screw speed (300-330 RPM) on expansion ratio (ER), breaking strength (BS), overall acceptability (OAA) score and water solubility index (WSI) of extrudates were investigated using central composite rotatable design (CCRD). Significant regression models explained the effect of considered variables on all responses. DFM incorporation level was found to be most significant independent variable affecting on extrudates characteristics followed by extruder barrel temperature and then screw rpm. Feed moisture content did not affect extrudates characteristics. As DFM level increased (7.5 % to 20 %), ER and OAA value decreased. However, BS and WSI values were found to increase with increase in DFM level. Based on the defined criteria for numerical optimization, the combination for the production of DFM incorporated extruded snack with desired sensory attributes was achieved by incorporating 10 % DFM (replacing rice flour in flour blend) and by keeping 20 % moisture content, 312 screw rpm and 125 °C barrel temperature.