Structural and textural characterization of corn–lentil extruded snacks

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.

Effect of the storage process on quality characteristics of hemp-enriched "tsoureki" a rich-dough baked Greek product

The effects of the storage process on the quality characteristics of a hemp-enriched "tsoureki" (a rich-dough baked Greek product, rich-dough baked product [RDBP]) were investigated. The wheat flour was substituted with defatted hemp flour at selected ratios (0%-50% hemp:wheat flour). The baked products were stored at 25°C and at specific time intervals (0, 1, 4, 7, 10, and 14 days), and their properties were determined, including moisture content, water activity, structure, texture, color, total phenolic content (TPC), and antioxidant activity. Moreover, analyses of phenolic compounds were performed using quadrupole time of flight liquid chromatography-mass spectroscopy, identifying 14 compounds. Both the first-order kinetic model and modified Avrami equation, including the hemp-to-wheat ratio effect in the rate constant, well described the changes in the quality characteristics. The results showed that storage time and hemp incorporation significantly affected the quality of the product. Water activity decreased from 0.901 to 0.859, whereas moisture content decreased from 30.52%-32.33% (0 days) to 26.97%-27.02% w.b. (14 days) with storage time for all hemp additions. Hardness was greatly affected by hemp flour addition and approached 14.72 and 17.85 N after 14 days of storage for 30% and 50% substitutions, respectively. Springiness and cohesiveness decreased with hemp addition and storage time. The color difference of the hemp-enriched products compared to the control sample increased during storage. TPC increased due to the addition of hemp flour, whereas 14 compounds were identified. Based on property correlation, the hemp-enriched RDBP-tsoureki held its high-quality characteristics for 7 days of storage and contained a significant amount of bioactive compounds. PRACTICAL APPLICATION: Industrially produced, defatted hemp is a promising byproduct that can be used to nutritionally enhance baked goods. Modeling results can be used for the prediction of the properties that define product storage ability and also that the hemp-enriched, rich dough-baked Greek "tsoureki" could be produced while maintaining total phenolic content and antioxidant activity during 7 days of storage. These findings are expected to be used in the future in baked goods industry applications to produce goods with an improved nutritional profile.

Effect of screw speed and die temperature on physicochemical, textural, and morphological properties of soy protein isolate-based textured vegetable protein produced via a low-moisture extrusion

In this study, textured vegetable protein (TVP) based on soy protein isolate, wheat gluten, and corn starch was prepared at a 5:3:2 (w/w) ratio using a low-moisture extrusion process. To evaluate the effects of extrusion parameters, die temperature and screw rotation speed, on the properties of TVP, these two parameters were manipulated at a constant barrel temperature and moisture content. The results indicated that increasing the die temperature increased the expansion ratio while decreasing the density of the extrudates. Simultaneously, increasing the screw rotation speed clearly increased the specific mechanical energy of the TVP. Furthermore, mathematical modelling suggested that the expansion ratio increases exponentially to the die temperature. However, extreme process conditions bring about a decrease in water absorption capacity and expansion ratio, as well as undesirable texture and microstructure. The results suggested that the properties of SPI-based TVP are directly influenced by the extrusion process parameters, screw speed and die temperature.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01207-8.

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.

Effects of Extrusion on Starch Molecular Degradation, Order-Disorder Structural Transition and Digestibility-A Review

Extrusion is a thermomechanical technology that has been widely used in the production of various starch-based foods and can transform raw materials into edible products with unique nutritional characteristics. Starch digestibility is a crucial nutritional factor that can largely determine the human postprandial glycemic response, and frequent consumption of foods with rapid starch digestibility is related to the occurrence of type 2 diabetes. The extrusion process involves starch degradation and order-disorder structural transition, which could result in large variance in starch digestibility in these foods depending on the raw material properties and processing conditions. It provides opportunities to modify starch digestibility by selecting a desirable combination of raw food materials and extrusion settings. This review firstly introduces the application of extrusion techniques in starch-based food production, while, more importantly, it discusses the effects of extrusion on the alteration of starch structures and consequentially starch digestibility in various foods. This review contains important information to generate a new generation of foods with slow starch digestibility by the extrusion technique.

Fabrication of Dragee Containing Spirulina platensis Microalgae to Enrich Corn Snack and Evaluate Its Sensorial, Physicochemical and Nutritional Properties

In this work, the possibility of enriching snacks with Spirulina palatensis (SP) powder as a dragee was studied. In dragee formulation, the effects of various levels of SP, sunflower oil, NaCl and sour whey powder on sensory, physicochemical and nutritional properties were investigated. The dragee formulation was optimized and the characteristics of the optimal sample were compared with the control sample (containing dragee without SP). The results showed that adding SP increased the flavonoids, total anthocyanin content, vitamins, protein, minerals, essential and non-essential amino acids and fatty acids, including ω3 and ω6, while decreasing the energy intake. Based on the results, the optimal dragee sample was formulated and prepared with a desirability of 0.955. The correlation coefficient indicated that the effective optimization process and the performance of the model were carried out properly. The addition of SP had a significant impact on all color parameters considered by the panelists, and the enriched sample was given a very good taste score (75.10 ± 2.923) and an outstanding overall acceptance rate (91.20 ± 1.549) by the panelists. Although morphological data from scanning electron microscopy showed the distribution of non-uniform SP particles relative to the addition of SP in the extruded product formulation, the preservation of more nutritional properties and the good acceptance of sensory evaluators indicated the success of the application in dragee formulation. Therefore, instead of being utilized in an extruder, we discovered that SP may be used as a dragee for snack fortification.

Textural, Color and Sensory Features of Spelt Wholegrain Snack Enriched with Betaine

The influence of different extrusion parameters, including screw speed (250–750 rpm), feed rate (15–25 kg/h) and feed moisture content (15–25%), on the textural and color properties of spelt wholegrain snack products produced on a co-rotating twin-screw extruder with added betaine was investigated. In order to determine the relative influence of input variables in the artificial neural network (ANN) model, Yoon’s interpretation method was used, and it was concluded that feed moisture content has the greatest influence on L* values, while screw speed has the greatest influence on a* and b* values. The softest samples were obtained at the lowest moisture content. Sensory analysis was carried out on selected samples, and it showed that betaine addition did not intensify the bitter taste. The sample with the largest expansion exhibited the lowest hardness and chewiness before and after immersion in milk, and this sample is the most suitable for enrichment with betaine.

Effect of flaxseed (Linum usitatissimum L.) flour and yerba mate (Ilex paraguariensis) extract on physicochemical and sensory properties of a gluten free corn-based snack

Flaxseed (Linum usitatissimum L.) and yerba mate (Ilex paraguariensis) are particularly interesting as functional ingredients due to their high content of essential omega 3-fatty acids and antioxidant properties, respectively. The objective of this work was to formulate a corn snack enriched with flaxseed flour and yerba mate extract and evaluate its physicochemical and sensory properties. Flaxseed flour, added at three levels 1, 3 and 5%, increased the water activity, moisture content and cohesiveness, and decreased the hardness and plastic deformation of the samples. The flour also changed the superficial colour and made the microstructure more compact. On the contrary, yerba mate extract (1 and 3%) decreased the water activity, moisture content and cohesiveness, counteracting the effect of flaxseed flour. Yerba mate increased the plastic deformation and the antioxidant activity of the snacks. The colour was not modified and the microstructure was more fragmented in the presence of yerba mate. Sensory evaluation suggested that flaxseed flour and yerba mate affected the flavour but did not modify the colour and crunchiness of the product.

Development of novel functional snacks containing nano-encapsulated resveratrol with anti-diabetic, anti-obesity and antioxidant properties

In this study, functional snacks with addition of nanoenapsuated resveratrol were prepared to evaluate the nutraceutical and physical properties. The nanoencapsulated resveratrol was prepared from horse-chestnut (HRP), water-chestnut (WRP) and lotus-stem starch particles (LRP) and added to the wheat flour at the level of 0.4% for preparation of snacks by extrusing process. After extrusion, 43-53% and 5.42% of resveratrol was retained in snacks containing encapsulated and free resveratrol (FRP), respectively. The HRP, WRP and LRP showed significantly less peak viscosities and less elastic behaviour than native product (NP) which can influence the human sensory perception. The shift of few peaks towards higher wavelength and presence of additional peaks at 1384, 1229, 1513 and 1613 cm^-1 depicts change in molecular pattern and presence of resveratrol in functional snacks. The functional snacks containing encapsulated resveratrol showed significantly higher antioxidant, anti-diabetic and anti-obesity properties than snacks containing no or free resveratrol.

Berrios J. Tiger Nut (Cyperus esculentus) as a Functional Ingredient in Gluten-Free Extruded Snacks

Tiger nut (TN) is a nutritious source of gluten-free flour, used generally in healthy beverages, but its incorporation in gluten-free extruded snacks has not been explored. TN flour was blended at different concentrations (up to 70%) with rice flour and soluble fiber, for the development of gluten-free snacks on a twin-screw extruder. The effect of TN inclusion in the formulations was evaluated on relevant physiochemical characteristics of the snacks. Viscoamylograph of the raw formulations showed that TN addition increased (p < 0.01) onset temperature and delayed peak viscosity. In the extruded flours, TN contributed to limit the starch degradation during extrusion. Diameter, expansion ratio, true density, and total pore volume of the extrudates were reduced (pf < 0.01) by the increased TN content in the formulations, while bulk density rose. The surfaces of the extruded snacks were modified by the increasing inclusion of TN in substitution of rice in the formulations. Extrudates containing 10% TN showed the best overall texture profile. Moreover, TN addition enhanced the ash and protein content of the snacks and increased their total antioxidant activity. This study demonstrated that incorporation of 10% TN flour into rice-based formulation was suitable for making gluten-free snacks with acceptable physical properties.

Quick assessment of the potato chip crispness using the mechanical-acoustic measurement method

Traditional assessment method for the food crispness was sensory analysis which was time consuming and needed experienced panelists. Aiming to to develop a quick evaluation of the food crispness, a mechanical-acoustic testing method was proposed where two parameters-maximum force (Fmax) and maximum acoustic energy in unit time (SEmax) were applied to assess the crispness of dried potato chips. It was found the mechanical-acoustic testing was completed in about 1.2 s and the potato chips had a statistic distributions for Fmax and SEmax. The brand A potato chips had a statistic average Fmax of 13.48 N and SEmax of 93.51 mV·ms. Three kinds of potato chips can be effectively differentiated according to the statistic average SEmax and Fmax. Sensory “crispness” had a good correlation with the statistic average SEmax. This work shows that it is feasible for a quick measurement of the food crispness using this mechanical-acoustic method.

Pea starch exhibits good expansion characteristics under relatively lower temperatures during extrusion cooking

Extrusion processing characteristics of pea starch were studied as impacted by various extrusion cooking processing variables, including, moisture content (15%, 17.5%, and 20% w.b.), temperature (120, 135, and 150 °C), and screw speed (150, 200, and 250 rpm), in a co-rotating twin-screw extruder. Physicochemical properties such as radial expansion ratio (ER), unit density (UD), water absorption index (WAI), and water solubility index (WSI) were measured. ER of the extrudates ranged between 2.52 and 3.63. These values of ER were significantly high, although relatively lower compared to the highest values reported in the literature for corn and rice extrudates. The UD values for all the extrudates ranged from 0.12 to 0.35 g/cm3 , WAI, and WSI values ranged from 10.98 to 12.10 g/g and from 0.12% to 7.73%, respectively. Both screw speed and moisture content had significant impacts on the ER (P < 0.01). The highest ER was observed for the extrusion cooking conditions of the lowest moisture content level (15%), lowest barrel temperature (120 °C), and lowest screw speed (150 rpm). The cross-sectional microstructure of the extrudates showed that the samples with a high ER had thick and elongated pores. The results of this study indicate that pea starch is a viable ingredient for making puffed extruded products. PRACTICAL APPLICATION: The food industry can utilize the information generated from this study in the development of extruded expanded food products with pea starch. The specific information related to process conditions can assist the food industry in determining the ideal conditions for extrusion cooking in the production.

Chemical Comparison of White Ginseng before and after Extrusion by UHPLC-Q-Orbitrap-MS/MS and Multivariate Statistical Analysis

Ultrahigh-performance liquid chromatography Quadrupole-Orbitrap tandem mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) was used to compare the composition of ginsenosides in white ginseng (WG) and extruded white ginseng (EWG). A total of 45 saponins, including original neutral ginsenosides, malonyl-ginsenosides, and chemical transformation of ginsenosides, were successfully identified in both WG and EWG. Multivariate statistical analyses including supervised orthogonal partial least squared discrimination analysis (OPLS-DA) and hierarchical clustering analysis (HCA) were used to analyze components of white ginseng before and after extrusion. As a result, three ginsenosides (malonyl (M)-Rb1, M-Rb2, and M-Rc) were found to be increased in WG, while three ginsenosides (Rb2, Rc, and Rg1) were elevated in EWG. In the OPLS-DA S-plot, the different compositions of ginsenoside that were distinguished between WG and EWG were screened out. Experimental results indicate that the UHPLC-Q-Orbitrap-MS/MS is a useful tool to characterize variations of ginsenosides in WG and EWG.

Optimized germinated soybean/cornstarch extrudate and its in vitro fermentation with human inoculum

The aim of this work was to optimise a soybean/cornstarch extrudate by adjusting a central composite design and to maximise a product with a high protein and resistant starch (RS) content by evaluating the indigestible fractions through in vitro colonic fermentation and production of short-chain fatty acids (SCFAs) with potential health benefits. According to the response surface analysis and RS maximisation results, an optimisation of the independent variables was obtained as follows: 32.5% feed moisture, 144 °C extrusion temperature and a proportion of 44% germinated soybean flour and 56% cornstarch. A product with a 2.11% expansion index, 6.25 N hardness, a glycaemic index of 49 and 12% resistant starch was obtained. The optimised extrudate showed a 36% indigestible fraction and high fermentability with respect to that of the lactulose control. Furthermore, the decrease in pH was inversely proportional to the production of SCFAs and the volume of gas generated. Acetic, propionic, and butyric acids were produced at a molar ratio of 62:27:11, while the highest SCFA concentrations were found 48 h after incubation. The RS of the optimised extruder was a viable substrate for in vitro colonic fermentation, suggesting that it is a good food source to produce SCFAs, which could exert an effect on the regulation of lipid and glucose metabolism.

Consumer acceptance and sensory drivers of liking for high plant protein snacks

BACKGROUND

Consumers are being encouraged to increase the proportion of plant protein in their diet to tend to a sustainable food system. Solutions could include developing a food rich in plant protein. However, these new products have an interest only if they are in accordance with expectation and the liking of consumers. In this context, extruded snack balls were developed to explore the sensory drivers of liking and barriers to consumption of formulated products with a high level of plant proteins. Eight different products varying in the type of cereal flour (rice or wheat) and pea flour content (from 60% to 90%) were developed following a factorial design. Eighty omnivore and 72 flexitarian consumers were recruited to evaluate the liking of these products. In addition, their sensory properties were described by a trained panel according to a profile method.

RESULTS

The cereal type had globally more influence on liking than the percentage of pea. However, liking was inversely correlated with pea flour content, regardless of the cereal type. The main drivers of liking are texture criteria (in particular crispy and puffy), whereas flavor perception (pea, green) constitutes a barrier to acceptance. Interestingly, very few differences of liking were observed depending on the diet of consumers even though the attitudes of flexitarian'towards such type of products differed from those of omnivores. We identified three clusters of consumers based on their preferences. Pea flavor acceptance or rejection could explain these clusters. Although most consumers rejected pea flavor, approximately 40% of the participants preferred the products with highest pea content.

CONCLUSION

The results of the present study will help provide guidance for innovative plant food design and formulation. © 2019 Society of Chemical Industry.

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.

Effects of extrusion with CO2 injection on physical and antioxidant properties of cornmeal-based extrudates with carrot powder

Carrot powder and cornmeal were extruded at ratios of 0:100, 10:90, and 20:80 with and without CO₂ injection at die temperatures of 80, 100, and 120 °C. The effects of the composition of the extrudate, die temperature, and CO₂ injection on physicochemical and antioxidant properties of extruded products were studied. The results showed that die temperature had a significant effect on expansion ratio (ER), specific length, piece density, color, water absorption index (WAI), and water solubility index (WSI) (p < 0.05). The injection of CO₂ significantly affected the ER, WAI, WSI, lightness, redness, microstructure, total phenolic content, and the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity of extrudates (p < 0.05). Increasing the proportion of carrot powder in extrudates resulted in better antioxidant properties and higher levels of crude ash, crude fat, crude protein, and redness; however, it resulted in lower WAI, lightness, and yellowness (p < 0.05). The study demonstrated that extrusion with CO₂ injection and addition of carrot powder may improve the nutritional quality and structure-forming ability of extrudates.

Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review

Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process.

Development of protein, dietary fiber, and micronutrient enriched extruded corn snacks

The study was aimed to develop protein, dietary fiber, and micronutrient enriched corn snacks through extrusion processing. Corn snacks supplemented with chickpea, defatted soy flour (20-40/100 g) and guar gum (7/100 g) were prepared through extrusion processing. Micronutrients (iron, zinc, iodine, and vitamins A, C, and folic acid) at recommended daily values were added in all formulations. Extruded corn snacks were analyzed for physical, textural, and sensory attributes. Results showed that piece density (0.34-0.44 g/cm³ ), moisture (3.40-5.25%), water activity (0.203-0.361), hardness (64.4-133.2 N), and cohesiveness (0.25-0.44) was increased Whereas, expansion ratio (3.72-2.64), springiness (0.82-0.69), chewiness (1.63-0.42), and resilience (1.37-0.14) was decreased as supplementation with soy and chickpea flour increased from 20 to 40/100 g. Overall corn snack supplemented with 15/100 g of soy and 15/100 g of chickpea flour got the highest acceptance from the sensory panelists.

PRACTICAL APPLICATIONS

The article focuses on physical, textural, and sensory attributes of extruded corn snacks enriched with protein, dietary fiber, and micronutrients Awareness about the importance of healthy snacks has grown among the consumers during the last decade. Extruded snacks developed using nutrient rich ingredients with good textural and sensory properties has always remained a challenge for the snack industry. Texture of the extruded snacks varies a lot with high levels of protein and dietary fiber. This study is helpful for the development of healthy snacks especially in developing countries lacking storage infrastructure or tropical environment. Nutrient rich extruded snacks can also be used to alleviate malnutrition by incorporating in school lunch programs.

Effect of different flours on quality of legume cakes to be baked in microwave-infrared combination oven and conventional oven

The objective of this study was to compare the quality of legume cakes baked in microwave-infrared combination (MW-IR) oven with conventional oven. Legume cake formulations were developed by replacing 10 % wheat flour by lentil, chickpea and pea flour. As a control, wheat flour containing cakes were used. Weight loss, specific volume, texture, color, gelatinization degree, macro and micro-structure of cakes were investigated. MW-IR baked cakes had higher specific volume, weight loss and crust color change and lower hardness values than conventionally baked cakes. Larger pores were observed in MW-IR baked cakes according to scanning electron microscope (SEM) images. Pea flour giving the hardest structure, lowest specific volume and gelatinization degree was determined to be the least acceptable legume flour. On the other hand, lentil and chickpea flour containing cakes had the softest structure and highest specific volume showing that lentil and chickpea flour can be used to produce functional cakes.