The demand for healthy ready-to-eat foods like snacks is increasing. Physical modification of vegetal food matrices through extrusion generates significant changes in the chemical composition of the final product. There is a great variety of food matrices that can be used in extrusion, most of them being based on cereals, legumes, fruits, vegetables, or seeds. The aim of this review was to summarize the main effects of the extrusion process on the bioactive compounds content, namely phenolics, terpenes, vitamins, minerals, and fibers of vegetal mixes, as well as on their biological activity. The literature reported contradictory results regarding the changes in bioactive compounds after extrusion, mainly due to the differences in the processing conditions, chemical composition, physicochemical properties, and nutritional value of the extruded material and quantification methods. The thermolabile phenolics and vitamins were negatively affected by extrusion, while the fiber content was proved to be enhanced. Further research is needed regarding the interactions between bioactive components during extrusion, as well as a more detailed analysis of the impact of extrusion on the terpenes since there are few papers dealing with this aspect.

Replacement of refined wheat flour with milling fractions of quinoa seeds represents a useful way for the formulation of value-added baked products with beneficial characteristics to consumers. The aim of this study was to assess the chemical composition and physical properties of different particle sizes of quinoa flour on Falling number index (FN) and dough rheological properties determined by Mixolab in a planned research based on design of experiment by using full factorial design. The ash and protein contents were higher in medium particle size, whereas the carbohydrates presented a lower value, this fraction having also the highest water absorption and water retention capacity. The reduction of particles led to an increased swelling capacity and a decreased bulk density. The particle size significantly influenced the FN values in linear and quadratic terms (p < 0.05), showing a decrease with the particle size increasing. Particle size decrease significantly increased water absorption and the rate of protein weakening due to heat (C1–2), whereas starch gelatinization rate (C3–2), starch breakdown rate related to amylase activity (C3–4) and starch retrogradation speed (C5–4) decreased. By increasing the amount of quinoa flour (QF) in wheat flour, the dough stability and the torques C2, C3, C4 and C5 followed a decreased trend, whereas water absorption and dough development time rose. Optimization, determined by particle size and level of QF added in wheat flour based on which of the combination gives the best rheological properties, showed that the composite flour containing 8.98% quinoa flour of medium particle size was the most suitable.

The objective of this investigation was to evaluate the effects generated by amaranth flour (AF)—of different particle sizes (PS) added to white wheat flour from 0% to 20%—on the proximate composition, dough rheological behavior, and bread technological parameters. The reduction of particle size led to an increased hydration capacity of the wheat–amaranth composite flour, while bulk density decreased. Increasing the amount of AF and decreasing the PS led to a significant increase in protein, lipids, and ash contents, while the moisture and carbohydrates of the composite flour decreased. Increasing AF addition led to an increase in dough tenacity and a decrease in dough extensibility, while the PS had an irregular trend. The large particle size, at 15% and 20% levels of AF in wheat flour, increased significantly (p < 0.001) the dough tenacity and hardness, bread firmness, but decreased bread volume, porosity, and elasticity, while medium and small particles at 5–15% addition levels improved porosity and elasticity of the composite bread. Significant correlations (p < 0.05) were found between proximate composition, dough rheological characteristics, and bread quality for the wheat–amaranth composite flours. The results of this study are an important basis for the development of innovative wheat–amaranth bread recipes.

The present study aimed to investigate the influence of quinoa fractions (QF) on the chemical components of wheat flour (WF), dough rheological properties, and baking performance of wheat bread. The microstructure and molecular conformations of QF fractions were dependent to the particle size. The protein, lipids, and ash contents of composite flours increased with the increase of QF addition level, while particle size (PS) decreased these parameters as follows: Medium ˃ Small ˃ Large, the values being higher compared with the control (WF). QF addition raised dough tenacity from 86.33 to 117.00 mm H₂O, except for the small fraction, and decreased the extensibility from 94.00 to 26.00 mm, while PS determined an irregular trend. The highest QF addition levels and PS led to the highest dough viscoelastic moduli (55,420 Pa for QL_20, 65245 Pa for QM_20 and 48305 Pa for QS_20, respectively). Gradual increase of QF determined dough hardness increase and adhesiveness decrease. Bread firmness, springiness, and gumminess rises were proportional to the addition level. The volume, elasticity, and porosity of bread decreased with QF addition. Flour and bread crust and crumb color parameters were also influenced by QF addition with different PS.

Supplementation of refined wheat flour with buckwheat flour requires a good understanding of the impact of milling fractions, their functionality, and addition level on bread quality. The chemical and functional characteristics of different particle fractions (large, medium, and small) of buckwheat flour on dough Mixolab rheological properties to predict bread quality were investigated. Moisture content, proteins, ash, lipids, and carbohydrates varied irregularly depending on the particle size. The medium particle fraction is the richest in protein, lipid and ash, which are positively correlated with its water and swelling properties and negatively correlated with its volumetric density. The alpha-amylase activity increased with the particle size increase in composite flour. The Mixolab data revealed that the decrease of particle size increased water absorption, dough viscosity during the starch gelatinization and retrogradation stage, while the addition level increased the dough development time and gel stability, and decreased the rate of protein weakening. Following the optimization process and the desirability function approach, it was established that the most appropriate rheological properties are provided by buckwheat flour addition level of 10.75% for medium particle fraction. These results can be helpful for bakery producers to diversify baked products with the desired particle fraction with optimal technological and nutritional properties along with beneficial effects to consumers.

Amaranth is an underutilized pseudocereal that can be used to supplement wheat flour (WF) in order to improve the nutritional quality of bread. Bread digestibility is impacted by particle size which produces different nutritional properties. This research aims to evaluate the baking characteristics of optimal wheat–amaranth composite flour for each studied amaranth flour (AF) particle size at doses previously established based on an optimization process and to characterize from a physical, textural, nutritional, and sensorial point of view the obtained bread. The results revealed that the optimal wheat–amaranth composite flour with medium and small particle size, respectively showed a slightly lower α-amylase activity, while dough development time was significantly higher compared to the WF. A significant (p < 0.05) decrease was observed in the elasticity, deformation energy, and dynamic rheological parameters of the optimal composite dough for all the particle sizes, whereas fermentation parameters showed higher values compared to the control, indicating the ability of the gluten structure in large, medium, and small particle sizes of AF to hold the gas and to expand without collapsing. The physical, textural, and especially nutritional characteristics of the optimal WF-AF bread were enhanced. The sensory evaluation results revealed high scores (8.70) for the acceptability of optimal bread with a medium particle size as compared to wheat bread (8.25). The protein and ash content of the optimal breads with large, medium, and small AF particle sizes, respectively, increased significantly, from 8.92 to 10.58%, and 0.82 to 0.99%, respectively, relative to the wheat flour bread (8.35% and 0.72%, respectively). The mineral content was up to two times higher in the optimal breads compared to wheat flour bread. The findings generated from this study are helpful in bakery industry for designing products with enhanced nutritional properties and for introducing new products to the market.