Effect of barrel temperature and feed moisture on the physical properties of chickpea, sorghum, and maize extrudates and the functionality of their resultant flours—Part 1

Effect of extrusion cooking on the chemical and nutritional properties of instant flours: a review

Satisfying the nutritional requirements of consumers has made food industries focus on the development of safe, innocuous, easy-to-prepare products with high nutritional quality through efficient processing technologies. Extrusion cooking has emerged as a prominent technology associated with the nutritional and functional attributes of food products. This review aims to establish a theoretical framework concerning the influence of extrusion parameters on the functional and nutritional properties of precooked or instant flours, both as end-products and ingredients. It highlights the pivotal role of process parameters within the extruder, including temperature, screw speed, and raw materials moisture content, among others, and elucidates their correlation with the modifications observed in the structural composition of these materials. Such modifications subsequently induce notable changes in the ultimate characteristics of the food product. Detailed insights into these transformations are provided within the subsequent sections, emphasizing their associations with critical phenomena such as nutrient availability, starch gelatinization, protein denaturation, enhanced in vitro digestibility, reduction in the content of antinutritional factors (ANFs), and the occurrence of Maillard reactions during specific processing stages. Drawing upon insights from available literature, it is concluded that these effects represent key attributes intertwined with the nutritional properties of the end-product during the production of instant flours.

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

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

Evaluation of the Physical, Chemical, Technological, and Sensorial Properties of Extrudates and Cookies from Composite Sorghum and Cowpea Flours

In recent years, there has been a growing demand for gluten-free and functional products, driven by consumer preferences for healthier and more diverse food choices. Therefore, there is a need to explore new ingredients that can be used as alternatives to traditional gluten-containing grains. Thus, this work evaluated the physical, chemical, technological, and sensorial properties of extrudates and cookies from composite tannin sorghum (rich in resistant starch) and white cowpea flours. Extrudates and cookies were produced from a composite flour made of sorghum and cowpea, at a sorghum:cowpea flour ratio of 70:30, 50:50, and 30:70. Then, raw flours, cookies, and extrudates were characterized (dietary fiber, resistant starch, proteins, antioxidant capacity, pasting properties, etc.). Results obtained for particle size distribution and bulk density indicated that the particles increased and the color changed with the addition of cowpea flour. The raw tannin sorghum flour had a higher resistant starch concentration (36.3%) and antioxidant capacity (211.2 µmolTE/g), whereas cowpea flour had higher levels of proteins (18.7%) and dietary fiber (20.1%). This difference in the raw flour composition contributed to the nutritional value of the extrudates and cookies, especially the cookies which undergo dry heat and had higher retention of resistant starch and antioxidants. Moreover, sorghum flour presented a higher tendency to retrograde (high setback), which was decreased by the addition of cowpea flour. Overall acceptance and intention to purchase were higher for extrudates with 100% sorghum flour (6.52 and 68.3%, respectively) and cookies with 70% cowpea flour (7.03 and 76.7%, respectively). Therefore, nutritious and functional gluten-free extrudates and cookies, of good acceptability, can be produced from composite tannin sorghum and white cowpea flours.

Effect of thermal, nonthermal, and combined treatments on functional and nutritional properties of chickpeas

Cicer arietinum or chickpea is an important and highly nutritious pulse, a source of complex carbohydrates, proteins, vitamins, and minerals, considered non-allergenic, and non-GMO crop. Processing technologies play an important role in modifying some chickpea properties and thus increasing its nutritional and health benefits. Herein is summarized and compared the available data on nutritional and functional aspects caused by thermal, nonthermal, and combinations of treatments for chickpea processing. The study focuses on describing the processing conditions necessary to change chickpea matrices aiming to enhance compound bioavailability, reduce anti-nutritional factors and modify functional characteristics for industrial application in product development. Thermal and nonthermal treatments can modify nutrient composition and bioavailability in chickpea matrices. Thermal treatments, moist or dry, prevent microbial spoilage, increase product palatability and increase protein quality. Nonthermal treatments aim to shorten the processing time and use less energy and water sources. Compared to thermal treatments, they usually preserve organoleptic attributes and bioactive compounds in chickpea matrices. Some treatment combinations can increase the efficacy of single treatments. Combined treatments increase antioxidant concentration, protein digestibility and available starch contents. Finally, despite differences among their effects, single and combined treatments can improve the nutritional and physicochemical properties of chickpea matrices.

Enhancing the Techno-Functionality of Pea Flour by Air Injection-Assisted Extrusion at Different Temperatures and Flour Particle Sizes

Industrial applications of pulses in various food products depend on pulse flour techno-functionality. To manipulate the techno-functional properties of yellow pea flour, the effects of flour particle size (small vs. large), extrusion temperature profile (120, 140 and 160 °C at the die) and air injection pressure (0, 150 and 300 kPa) during extrusion cooking were investigated. Extrusion cooking caused the denaturation of proteins and gelatinization of starch in the flour, which induced changes in the techno-functionality of the extruded flour (i.e., increased water solubility, water binding capacity and cold viscosity and decreased emulsion capacity, emulsion stability, and trough and final viscosities). In general, the large particle size flour required less energy input to be extruded and had higher emulsion stability and trough and final viscosities compared to the small particle size flour. Overall, among all of the treatments studied, extrudates produced with air injection at 140 and 160 °C had higher emulsion capacity and emulsion stability, making them relatively better suited food ingredients for emulsified foods (e.g., sausages). The results indicated air injection's potential as a novel extrusion technique combined with modification of flour particle size distribution and extrusion processing conditions to effectively manipulate product techno-functionality and broaden the applications of pulse flours in the food industry.

Butterfly Pea Flower as a Novel Ingredient to Produce Antioxidant-Enriched Yellow Pea-Based Breakfast Cereals

Butterfly pea flower (BP) is a rich source of bioactive components and can potentially be utilized to produce appealing, wholesome foods. Antioxidant and dietary fiber-enriched breakfast cereals were produced by extrusion cooking using blends of BP and yellow pea flour (YP). BP was added to YP at 0%, 5% and 10% levels (w/w), respectively, and extruded at two temperature profiles with die temperatures of 130 and 150 °C. Incorporation of BP significantly (p < 0.05) improved the total phenolics content, antioxidant properties, and insoluble and total dietary fiber content of the extrudates, with 10% BP extrudates showing the highest values. At a die temperature of 150 °C, the extrudates had a higher expansion ratio, a lower dry hardness, and a higher dry crispiness as compared to those at 130 °C. The color of BP-incorporated extrudates was darker and bluer as compared to the no-BP extrudates. The 10% BP extrudates retained relatively more of their hardness, crispiness, and crunchiness after soaking, indicating a better bowl-life and, therefore, better suitability of this blend formula for breakfast cereal production. Overall, this research shows that healthier breakfast cereals with appealing color and relatively longer bowl-life can be produced using BP, making BP a potential novel ingredient for extrusion formulations.

Application of emerging technologies to obtain legume protein isolates with improved techno-functional properties and health effects

Current demand of consumers for healthy and sustainable food products has led the industry to search for different sources of plant protein isolates and concentrates. Legumes represent an excellent nonanimal protein source with high-protein content. Legume species are distributed in a wide range of ecological conditions, including regions with drought conditions, making them a sustainable crop in a context of global warming. However, their use as human food is limited by the presence of antinutritional factors, such as protease inhibitors, lectins, phytates, and alkaloids, which have adverse nutritional effects. Antitechnological factors, such as fiber, tannins, and lipids, can affect the purity and protein extraction yield. Although most are removed or reduced during alkaline solubilization and isoelectric precipitation processes, some remain in the resulting protein isolates. Selection of appropriate legume genotypes and different emerging and sustainable facilitating technologies, such as high-power ultrasound, pulsed electric fields, high hydrostatic pressure, microwave, and supercritical fluids, can be applied to increase the removal of unwanted compounds. Some technologies can be used to increase protein yield. The technologies can also modify protein structure to improve digestibility, reduce allergenicity, and tune technological properties. This review summarizes recent findings regarding the use of emerging technologies to obtain high-purity protein isolates and the effects on techno-functional properties and health.

Impact of drum drying conditions on functional properties and flow behavior of gluten-free instant fermented mung bean-rice soup

The effect of drum drying conditions on functional properties of a nutritious, gluten-free instant fermented (tarhana) soup which was developed for celiac people by a partial substitution of rice flour with mung bean flour (1:1, w/w) was investigated. Response surface method was used to optimize drum drying process conditions for development of mung bean fortified soup. Impacts of independent variables; feed moisture (45-55-65%), drum rotating speed (0.6-1.4-2.2 rpm) and steam pressure (75-85-95 psi) on water and oil absorption capacities, foam capacity, foam stability, protein solubility and flow behavior were investigated. Responses were significantly affected by process variables. Feed moisture was the main factor affecting water and oil absorption capacity and viscosity, while drum rotating speed primarily affected protein solubility, foam capacity and stability. Maximum foaming abilities were obtained at high drum speeds and low feed moistures. Optimum process conditions were determined as 62.22% feed moisture, 2.20 rpm rotating speed, 75 psi pressure, with a desirability value of 0.693. The best achievable response values predicted by numerical optimization for these combinations were water absorption capacity: 3.25 mL/g, oil absorption capacity: 0.51 mL/g, protein solubility: 2.68 mg/mL, foam capacity: 0.07 mL/mL, foam stability: 14.59 min, and consistency coefficient: 2.04. Gluten-free mung bean-rice soup with increased protein content (20.52-22.62%) and functional properties along with higher dietary fiber (2.63-3.94%) will contribute to life quality of celiac patients.

A review of extrusion-modified underutilized cereal flour: chemical composition, functionality, and its modulation on starchy food quality

Compared with three major cereals, underutilized cereals (UCs) are those with less use but having abundant bioactive components and better functionalities after proper processing. As a productive and energy-efficient technology, extrusion has been used for UC modification to improve its technological and nutritional quality. Extrusion could induce structural and quantitative changes in chemical components of UC flour, the degree of which is affected by extrusion intensity. Based on the predominant component (starch), functionalities of extruded underutilized cereal flour (EUCF) and potential mechanisms are reviewed. Considering bioactive compounds, it also summarizes the physiological functions of EUCF. EUCF incorporation could modulate the dough rheological behavior and starchy foods quality. Controlling extrusion intensity or incorporation level of EUCF is vital to achieve sensory-appealing and nutritious products. This paper gives comprehensive information of EUCF to promote its utilization in novel staple foods.

Chickpea protein ingredients: A review of composition, functionality, and applications

Chickpea (Cicer arietinum L.) is a pulse consumed all over the world, representing a good source of protein, as well as fat, fiber, and other carbohydrates. As a result of the growing global population the demand for the protein component of this pulse is increasing and various approaches have been proposed and developed to extract same. In this review the composition, functionality, and applications of chickpea protein ingredients are described. Moreover, methods to enhance protein quality have been identified, as well as applications of the coproducts resulting from protein extraction and processing. The principal dry and wet protein enrichment approaches, resulting in protein concentrates and isolates, include air classification, alkaline/acid extraction, salt extraction, isoelectric precipitation, and membrane filtration. Chickpea proteins exhibit good functional properties such as solubility, water and oil absorption capacity, emulsifying, foaming, and gelling. During protein enrichment, the functionality of protein can be enhanced in addition to primary processing (e.g., germination and dehulling, fermentation, enzymatic treatments). Different applications of chickpea protein ingredients, and their coproducts, have been identified in research, highlighting the potential of these ingredients for novel product development and improvement of the nutritional profile of existing food products. Formulations to meet consumer needs in terms of healthy and sustainable foods have been investigated in the literature and can be further explored. Future research may be useful to improve applications of the specific coproducts that result from the extraction of chickpea proteins, thereby leading to more sustainable processes.

Development of sorghum-based shortbread biscuits from "muskwari" flour

In order to produce biscuits from off-season sorghum, a local "Muskwari" sorghum was milled and sieved. This flour was used to produce shortbread biscuits with different substitutions rates of wheat flour to that of sorghum. The standard formulation of this same type of shortbread biscuits was used and biscuits were produced with incorporation rates of wheat flour to that of sorghum, from 0% to 100%, with a gap of 10 between two consecutives percentages. The technological characterization of the sorghum flour produced indicates a good water absorption capacity, and interesting solubility index and swelling rate. Technological aspect indicated that by changing speed and kneading time, resting the dough, it is possible to produce 100% sorghum flour shortbread biscuits. Shortbread biscuits made from 70% of wheat flour incorporation had the best average scores for overall preference criteria (6.97 ± 1.30), color (7.1 ± 1.45), and texture (6.62 ± 1.54). For smell and taste criteria, the 40% biscuits and the witness received the highest average scores, respectively, namely 6.77 ± 1.55 for smell and 7.12 ± 1.29 for taste. Analysis of the nutritional and energy intake of the control biscuit and the 70% substitution revealed that between the two, the latter had a significantly higher intake of total carbohydrates (58.51 g), dietary fiber (2.15 g), and total energy (454.1 kcal.