Comparison of properties of native and extruded amaranth (Amaranthus cruentus L. – BRS Alegria) flour

Fortification of Chinese Steamed Bread Through Broken Ganoderma lucidum Spore Powder Incorporation: Effects on Physicochemical and Quality Properties

Broken Ganoderma lucidum spore powder (BGLSP) is abundant in nutrients and bioactive compounds, rendering it a suitable functional raw material for food applications. This study examined the impact of incorporating BGLSP (ranging from 0.5% to 10%) on the physicochemical properties of flour blends, dough, and the quality of Chinese steamed bread (CSB). The results indicated that with increasing BGLSP content, the a* value, onset temperature, peak temperature, water absorption, development time, and dough stability all exhibited an upward trend in the flour blends and dough, while the L* value and protein network weakening decreased. When compared to the control sample, the inclusion of 10% BGLSP resulted in a reduction in the spread ratio, specific volume, cohesiveness, and springiness of CSB, while simultaneously increasing its hardness, chewiness, and gumminess. The observed odor variations among samples were primarily ascribed to the proportions of aldehydes and ketones. Notably, sensory evaluation demonstrated that the flavor attributes of BGLSP-enhanced samples were superior to those of the control sample. In conclusion, the incorporation of BGLSP at concentrations ranging from 0.5% to 1% is deemed optimal for CSB, offering novel insights into the application of BGLSP within the food industry.

Structural and functional properties of a high moisture extruded mixture of pea proteins (Pisum sativum), amaranth flour (Amaranthus hypochondriacus), and oat flour (Avena sativa)

Textured vegetable proteins (TVP) are an alternative to meet the increasing demand for non-animal food. This study aimed to develop a TVP from mixtures with 45 % pea protein isolate (PPI) enriched with amaranth (AF) and oat (OF) flours using high-moisture extrusion technology (HME) varying the moisture (50-70 %) and the temperature in the second heating zone of the extruder (110-140 °C). After extrusion, all samples demonstrated higher values of water absorption capacity (WAC) than non-extruded mixtures. Mixture of AF:OF:PPI (40:15:45 %) extruded at 60 % moisture and 135 °C showed promising functional properties with WAC and WSI values of 3.2 ± 0.2 g H2O/g and 24.89 ± 2.31 %, respectively, and oil absorption capacity (OAC) of 1.3 g oil/g. The extrusion process altered the thermal and structural properties of proteins promoting a desirable fibrous structure. This confirms the feasibility of using HME to develop TVP based on PPI, AF, and OF.

Impact of genotypic variation and cultivation conditions on the techno-functional characteristics and chemical composition of 25 new Canadian quinoa cultivars

The utilization of quinoa in food production requires comprehensive information on its processing characteristics. Twenty-five new quinoa cultivars developed by the Northern Quinoa Breeding Program, grown in three Canadian locations over two seasons, were characterized for their proximate composition, pasting properties, thermal properties, water absorption index, water solubility index, foaming capacity, foaming stability, oil holding capacity, and emulsion activity crucial for potential food applications. Results showed significant variations in the proximate composition among the cultivars, which was also influenced by the growing location and harvest year. Significant differences (p < 0.05) were also observed in the pasting properties, thermal stability, hydration properties, foaming properties, oil holding capacity, and emulsion activity. The hierarchical cluster and principal component analyses were associated with five distinct clusters of quinoa cultivars, each with unique techno-functional attributes, suggesting their potential for different food applications. These findings emphasize the need for further research to explore the performance of quinoa flours in specific food products and their impact on end-product quality.

Techno-functional properties of gluten-free pasta from hyperprotein quinoa flour

Many consumers who are aware of the importance of good nutrition demand quality food alternatives. In particular, many of them are looking for quality, plant-based protein sources such as quinoa. The objective of this work was to evaluate the techno-functional properties of gluten-free pasta from hyperprotein quinoa flour. Pasta mixes were made from gluten-free flours, corn, rice, cassava starch, hyperprotein quinoa flour and defatted high protein quinoa flour, which were subsequently extruded. The flow rheological properties of aqueous dispersions of flour mixtures were analyzed before and after the pasting test. In addition, thermal properties were analyzed by differential scanning calorimetry and structural properties by Fourier transform infrared spectroscopy. The results showed a change of flow from dilatant (n > 1) to pseudoplastic (n < 1) after the pasting test. In addition, a positive correlation was observed between hyperprotein defatted quinoa flour and viscosity, and a negative correlation with hyperprotein quinoa flour. Regarding thermal properties, it was found that all blends showed low gelatinization enthalpy values, attributed to the high proportions of HQF and HDQF. Spectroscopic analysis showed that the extrusion did not significantly affect the native structure of the protein, by monitoring the intensities of the 1648 cm-1, 1656 cm-1 and 1667 cm-1 bands associated with the Random coil, α-helix, β-turns secondary structures, respectively. It was possible to conclude that both hyperprotein quinoa flour and defatted hyperprotein quinoa flours have a differential influence on the techno-functional properties of pasta. The first one, tends to reduce viscosity and consistency while the second one tends to increase it. Finally, moderate temperatures during extrusion did not cause significant changes in starch and protein structures as determined by spectroscopic study.

Effect of different extrusion methods on physicochemical properties and qualities of noodles based on rice flour

Rice noodles have been manufactured in the food industry using different extrusion methods, such as traditional and modern extrusions, which affect the noodle structure and qualities. Therefore, the effects of the extrusion process on qualities of rice noodles using the same blend of rice flour and crosslinked starch were evaluated. In this study, a capillary rheometer was used as an alternative approach to simulate the traditional extrusion method in which the noodles are obtained by continuously pressing the pregelatinized noodle dough through a die. For modern extrusion, a twin-screw extruder was employed to obtain the noodles in a one-step process. The optimal range of moisture content used in the formulation was studied. Upon cooking, the noodles showed a decrease in cooking time and cooking loss with increasing moisture content in the formulation. All cooked noodles showed comparable tensile strength, but those extruded by a twin-screw extruder had substantially greater elongation. Scanning electron micrographs revealed that the noodles prepared using the extruder had a denser starch matrix, while those obtained from a capillary rheometer showed the aggregation of starch fragments relevant to the existence of starch gelatinization endotherm from differential scanning calorimetry. This indicated that the extrusion process using the twin-screw extruder provided a more uniform starch transformation, i.e., more starch granule disruption and gelatinization, thus giving the noodles a more coherent structure and better extensibility after cooking. The obtained results suggested that different thermomechanical processes used in the noodle industry gave the extruded rice noodles different qualities respective to their different microstructures.

Techno-Functional Properties of Corn Flour with Cowpea (Vigna unguilata) Powders Obtained by Extrusion

Legumes are a good source of vegetal protein that improves diets worldwide. Cowpea has been used as fortification agents in some traditional corn foods in developing countries such as Colombia. The work aimed to evaluate the physicochemical properties of extruded mixtures of corn and cowpea flours to assess the use of these mixes as vegetable protein ingredients. Corn flour was mixed with 15, 30, and 50% of cowpea flour and extruded for this proposal. After extrusion, mixtures were ground to produce a powder. Techno-functional properties of powders as water content, hygroscopicity, water absorption, fat absorption, water solubility index, swelling index, bulk density, Hausner ratio, Carr index, and porosity were evaluated in the mixtures, extrudates, and obtained powders to assess the effect of the addition of cowpea on these properties. Results showed that processing powder obtained by extrusion and drying could be used as a powder to regenerate with water as a source of protein. Moreover, storing processing samples in sections (pellet format) is convenient to avoid wetting since this format is less hygroscopic and the same mass occupies less storage volume than powders.

Germination of White and Red Quinoa Seeds: Improvement of Nutritional and Functional Quality of Flours

Quinoa is an Andean grain, classified as pseudocereal and the exploitation of its nutritional profile is of great interest for the cereal-based industry. The germination of quinoa seeds (white and red royal) was tested at 20 °C for different times (0, 18, 24 and 48 h) to select the best conditions for improving the nutritional quality of their flours. Changes in proximal composition, total phenolic compounds, antioxidant activity, mineral content, unsaturated fatty acids and essential amino acids profiles of germinated quinoa seeds were determined. In addition, changes in structure and thermal properties of the starch and proteins as consequence of germination process were analyzed. In white quinoa, germination produced an increase in the content of lipids and total dietary fiber, at 48 h, the levels of linoleic and α-linolenic acids and antioxidant activity increase, while in red quinoa, the component that was mostly increased was total dietary fiber and, at 24 h, increased the levels of oleic and α-linolenic acids, essential amino acids (Lys, His and Met) and phenolic compounds; in addition, a decrease in the amount of sodium was detected. On the basis of the best nutritional composition, 48 h and 24 h of germination were selected for white and red quinoa seeds, respectively. Two protein bands were mostly observed at 66 kDa and 58 kDa, being in higher proportion in the sprouts. Changes in macrocomponents conformation and thermal properties were observed after germination. Germination was more positive in nutritional improvement of white quinoa, while the macromolecules (proteins and starch) of red quinoa presented greater structural changes. Therefore, germination of both quinoa seeds (48 h-white quinoa and 24 h-red quinoa) improves the nutritional value of flours producing the structural changes of proteins and starch necessary for obtaining high quality breads.

Effect of new type extrusion modification technology on supramolecular structure and in vitro glycemic release characteristics of starches with various estimated glycemic indices

Nowadays, the highly effective modified technology to starch with various digestibility is gaining interest in food science. Here, the interactions between glycemic release characteristics and fine supramolecular structure of cassava (ECS), potato (EPS), jackfruit seed (EJFSS), maize (EMS), wheat (EWS), and rice starches (ERS) prepared with improved extrusion modification technology (IEMS) were investigated. The crystalline structures of all extruded cooking starches changed from the A-type to V-type. IEMS-treated cassava, potato, and rice starches had broken α-1.6-glycosidic amylopectin (long chains). The others sheared α-1.4-glycosidic amylopectin. The molecular weight, medium and long chain counts, and relative crystallinity decreased, whereas the number of amylopectin short chains increased. The glycemic index (GI) and digestive speed rate constant (k) of ECS, EPS, EJFSS, and EWS were improved compared to those of raw starch. Although EMS and ERS had degraded molecular structures, their particle morphology changed from looser polyhedral to more compact with less enzymolysis channels due to the rearrangement of side chain clusters of amylopectin, leading to enzyme resistance. The starch characteristics of IEMS-treated samples significantly differed. EPS had the highest amylose content, medium chains, long chains, and molecular weight but lowest GI, relative crystallinity, and k. ERS showed the opposite results. Thus, IEMS may affect starches with different GIs to varying degrees. In this investigation, we provide a basis for wider applications of conventional crop starch in the food industry corresponding to different nutrition audience.

Physicochemical Changes of Heat-Treated Corn Grain Used in Ruminant Nutrition

Cereal grain is processed using different combinations of heat, moisture, time, and mechanical action in order to improve its digestibility. The objective of the present research was to quantitatively represent the physicochemical properties of raw and processed starch using an in vitro methodology, as well as to describe the changes that occurred after heat treatment, such as pelleting, steam flaking, micronization, and extrusion of corn. Based on the obtained results, pelleting, steam flaking, and micronization can be considered as mild heat treatment methods, whereas extrusion proved to be a severe heat treatment method. Analysis of functional and pasting properties implied a possible interaction between the degraded components in the steam-flaked sample, as well as in the micronized sample, through to a lesser extent. Additionally, the occurrence of dextrins was noted after extrusion. The obtained results indicate the existence of significant differences in the physicochemical properties of corn starch depending on the heat treatment applied, which could possibly affect rumen starch degradation traits.

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.

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.

Utilization of Amaranthus spp. grains in food

Recently there has been a rediscovery of some ancient crops due to increased consumer demands for a healthier diet with medicinal and therapeutic effects. One such crop is a pseudocereal Amaranthus sp., which is nutritionally more favourable than many widespread kinds of cereal and meets most of the requirements of modern diets. The incorporation of amaranth species in food formulations would expand the assortment of food products present on the market. The high nutritional quality and potential functionality of amaranth-based food products have been the subject of extensive scientific research. This study aims at reviewing the currently available data on the application of amaranth grains in the food industry and manufacturing and focuses on the functionalities of these products, providing an overview of the current amaranth value chain.

Utilization of Amaranthus spp. grains in food

Recently there has been a rediscovery of some ancient crops due to increased consumer demands for a healthier diet with medicinal and therapeutic effects. One such crop is a pseudocereal Amaranthus sp., which is nutritionally more favourable than many widespread kinds of cereal and meets most of the requirements of modern diets. The incorporation of amaranth species in food formulations would expand the assortment of food products present on the market. The high nutritional quality and potential functionality of amaranth-based food products have been the subject of extensive scientific research. This study aims at reviewing the currently available data on the application of amaranth grains in the food industry and manufacturing and focuses on the functionalities of these products, providing an overview of the current amaranth value chain.

Effects of soy flour types and extrusion-cooking conditions on physicochemical, microstructural and sensory characteristics of puffed rice snack base

The physicochemical properties of puffed rice snack base (PRSB) prepared via extrusion cooking under various feed moisture contents and screw speeds were investigated. The moisture content, screw speed, and soy flour type significantly (p < 0.05) affected the physicochemical properties of PRSB viz; size, density, porosity, color, breaking strength, crystallinity, water absorption index (WAI) and water solubility index (WSI). While, a slight effect on pasting properties was observed between PRSB added with defatted and full-fat soy flour, respectively. Soy flour lipids significantly (p < 0.05) influenced extrusion cooking conditions especially at high screw speed and feed moisture content. The result revealed that extrusion cooking with addition of full-fatty soy flour can be exploited as a viable method to produce PRS with a high expansion ratio and low breaking strength at recommended extrusion conditions of feed moisture content of 19 % and screw speed of 300 rpm.

Comparison of the Chemical and Technological Characteristics of Wholemeal Flours Obtained from Amaranth (Amaranthus sp.), Quinoa (Chenopodium quinoa) and Buckwheat (Fagopyrum sp.) Seeds

A sound fundamental knowledge of the seed and flour characteristics of pseudocereals is crucial to be able to promote their industrial use. As a first step towards a more efficient and successful application, this study focuses on the seed characteristics, chemical composition and technological properties of commercially available pseudocereals (amaranth, quinoa, buckwheat). The levels of starch, fat, dietary fiber and minerals were comparable for amaranth and quinoa seeds but the protein content is higher in amaranth. Due to the high amount of starch, buckwheat seeds are characterised by the lowest amounts of fat, dietary fibre and minerals. Its protein content ranged between that of amaranth and quinoa. Buckwheat seeds were larger but easily reduced in size. The lipid fraction of the pseudocereals mostly contained unsaturated fatty acids, with the highest prevalence of linoleic and oleic acid. Palmitic acid is the most abundant unsaturated fatty acid. Moreover, high levels of P, K and Mg were found in these pseudocereals. The highest phenolic content was found in buckwheat. Amaranth WMF (wholemeal flour) had a high swelling power but low shear stability. The pasting profile strongly varied among the different quinoa WMFs. Buckwheat WMFs showed high shear stability and rate of retrogradation.

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.

Physical and technofunctional properties of yellow pea flour and bread crumb mixtures processed with low moisture extrusion cooking

The potential utilization of yellow pea flour and bread crumb blends was investigated to generate nutritionally-dense extruded products with superior physical and/or technofunctional properties. Yellow pea flour mixed with bread crumb at different ratios were processed using low-moisture twin-screw extrusion cooking conditions to examine the effect of blending ratios and feed moisture contents on physical (that is, radial expansion index, extrudate density, microstructure, texture, and color) and technofunctional (that is, emulsifying capacity, emulsifying stability, water solubility [WS], water binding capacity [WBC], oil binding capacity [OBC], and pasting) properties of the final products. Compared to the two feed materials alone, samples produced with yellow pea flour and bread crumb blends showed lower hardness and higher crispiness. Moisture content (12% to 18%) was found to significantly affect physical and technofunctional properties. With an increase in feed moisture content from 12% to 18%, the WBC of the extrudates increased while the WS decreased. Extrudates produced with higher feed moisture content, and higher yellow pea flour content had higher setback viscosity. Among all formulas and feed moisture contents studied, extrudates produced with 50% yellow pea flour and 50% bread crumb at 12% feed moisture content had the highest radial expansion and bigger cells with thinner cell walls. This study has shown that incorporation of yellow pea flour and bread crumb in extrusion cooking process could be used to develop nutritionally-dense foods with improved physical and technofunctional properties.

Biomimetic corneal stroma using electro-compacted collagen

Engineering substantia propria (or stroma of cornea) that mimics the function and anatomy of natural tissue is vital for in vitro modelling and in vivo regeneration. There are, however, few examples of bioengineered biomimetic corneal stroma. Here we describe the construction of an orthogonally oriented 3D corneal stroma model (3D-CSM) using pure electro-compacted collagen (EC). EC films comprise aligned collagen fibrils and support primary human corneal stromal cells (hCSCs). Cell-laden constructs are analogous to the anatomical structure of native human cornea. The hCSCs are guided by the topographical cues provided by the aligned collagen fibrils of the EC films. Importantly, the 3D-CSM are biodegradable, highly transparent, glucose-permeable and comprise quiescent hCSCs. Gene expression analysis indicated the presence of aligned collagen fibrils is strongly coupled to downregulation of active fibroblast/myofibroblast markers α-SMA and Thy-1, with a concomitant upregulation of the dormant keratocyte marker ALDH3. The 3D-CSM represents the first example of an optimally robust biomimetic engineered corneal stroma that is constructed from pure electro-compacted collagen for cell and tissue support. The 3D-CSM is a significant advance for synthetic corneal stroma engineering, with the potential to be used for full-thickness and functional cornea replacement, as well as informing in vivo tissue regeneration. STATEMENT OF SIGNIFICANCE: This manuscript represents the first example of a robust, transparent, glucose permeable and pure collagen-based biomimetic 3D corneal stromal model (3D-CSM) constructed from pure electro-compacted collagen. The collagen fibrils of 3D-CSM are aligned and orthogonally arranged, mimicking native human corneal stroma. The alignment of collagen fibrils correlates with the direction of current applied for electro-compaction and influences human corneal stromal cell (hCSC) orientation. Moreover, 3D-CSM constructs support a corneal keratocyte phenotype; an essential requirement for modelling healthy corneal stroma. As-prepared 3D-CSM hold great promise as corneal stromal substitutes for research and translation, with the potential to be used for full-thickness cornea replacement.

Supramolecular structure of Artocarpus heterophyllus Lam seed starch prepared by improved extrusion cooking technology and its relationship with in vitro digestibility

Jackfruit seed starch (JFSS) was modified by an improved extrusion cooking technology (IECT), and the supramolecular structure, molecular weight, debranched chain length distributions, relative crystallinity (Rc), and amylose content, were studied. During IECT, the α-1.4-glycosidic bond in amylopectin was broken, which led to decreased radius of gyration (Rg), number-average molar mass (Mn), weight-average molar mass (Mw), long chains and Rc. The medium and short chains and PI (Mw/Mn) increased, while the amylose content hardly changed. The crystalline structure of JFSS was converted from A-type to V-type. Increasing the temperature and screw speed during the treatment significantly increased the medium and short chains and Rg, while it decreased the long chains, amylose, Mn, Mw, PI, and Rc. However, the opposite effect was observed when increasing the moisture content. The in vitro digestibility of JFSS was significantly improved after IECT, due to destruction of starch supramolecular structure according to principal component analysis.

Optimization of extrusion conditions for the production of instant grain amaranth-based porridge flour

Malnutrition is one of the foremost causes of death among children below 5 years in developing countries. Development of nutrient-dense food formulations using locally available crops has been proposed as a means to combat this menace. This study optimized the extrusion process for the production of a nutritious amaranth-based porridge flour. Least cost formulations containing grain amaranth, groundnut, iron-rich beans, pumpkin, orange-fleshed sweet potato, carrot, and maize were developed and evaluated by a sensory panel (n = 30) for acceptability using the 9-point hedonic scale. Extrusion process of the most acceptable porridge flour was optimized by response surface methodology (RSM). Barrel temperature (130-170°C) and feed moisture content (14%-20%) were the independent variables which significantly (p < .05) affected in vitro protein digestibility, vitamin A retention, total polyphenol, phytic content, and iron and zinc extractabilities. Optimization of the extrusion process improved the nutritional quality of the instant flour.

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.

Breadmaking performance and textural changes during storage of composite breads made from spelt wheat and different forms of amaranth grain

The objectives of the present study were to assess the baking properties of composite spelt wheat-amaranth blends and to study the staling of composite breads during a six-day storage. Different forms of amaranth grains were added to spelt bread formulation: native amaranth flour and flour from popped amaranth, including their scalded and non-scalded variants. Native amaranth flour (both scalded and non-scalded) gave loaves with the highest volume and contributed to significantly softer crumb but not in comparison to the control bread. Crumb resilience did not show significant differences among the breads but there were differences in the crumb stress relaxation parameters which indicated certain influence on the crumb viscoelastic properties. During storage, all samples developed firmer and less elastic crumbs. Drying loss and staling degree significantly increased with increased storage time. The staling rate was the highest in the bread with non-scalded amaranth flours (native and flour from popped amaranth). The changes in the crumb textural and elastic properties caused by staling turned significant after six days of storage. In general, inclusion of different forms of amaranth flour did not alter the staling of breads and they exerted similar behaviour during storage.

Evaluation of the nutritional quality of the grain protein of new amaranths varieties

The efforts for promoting the consumption of food of plant origin are increasingly growing. The amaranth grain is an important vegetable protein source, superior in content and quality to traditional cereals. In the central-west region of Argentina, new amaranth varieties have been obtained to optimize its agronomic traits and promote its use. In this work, the analysis of the wholemeal flour protein from seeds of two new varieties of Amaranthus cruentus var. Candil (CC) and Amaranthus hypochondriacus var. Dorado (HD), as well as from advanced lines of Amaranthus hypochondriacus x Amaranthus cruentus H17a (H17) and Amaranthus cruentus G6/17a (CG6), was carried out in order to elucidate their nutritional contribution to human diet. The amino acids profile and the chemical score (CS) were determined, and the protein quality was evaluated in-vivo through the following indexes: net protein utilization (NPU), true digestibility (tD), biological value (BV) and protein digestibility corrected amino acid score (PDCAAS). In general, the amino acids values of the different varieties exceeded the requirements established by the WHO/FAO/UNU; however, valine was the limiting amino acid in all cases. The values obtained (%) were within the following ranges: NPU, 33.56-46.04%; tD, 68.80-75.40%; BV, 44.53-64.28%; and PDCAAS, 23.69-36.19%. These results suggest that the new amaranth flours varieties can be adequate for human consumption and as complementary protein source.

The effect of moisture content on physicochemical properties of extruded waxy and non-waxy rice flour

The properties of waxy rice flour (WRF) and non-waxy rice flour (RF) were modified using an extrusion process with different feeding material moisture contents. WRF was more affected by the thermomechanical stress from extrusion; consequently, it had a lower glass transition temperature but higher water solubility index (WSI) indicating higher molecular degradation than extruded RF. The lower moisture content of the feeding flour caused more severe flour damage (coarser surface of the extruded flour) and lowered relative crystallinity compared to higher moisture content processing. Moreover, low moisture content processing led to complete gelatinization, whereas, partial gelatinization occurred in the higher moisture content extrusion. Consequently, the extruded flours had a lower peak viscosity and gelatinization enthalpy but a higher water absorption index and WSI than native flour. In conclusion, the rice flour type and the moisture content of the extrusion feeding flour affected the physicochemical properties of the extruded flour.