This study characterized and compared 13 gluten-free (GF) flours (rice, brown rice, maize, oat, millet, teff, amaranth, buckwheat, quinoa, chickpea, gram, tiger nut, and plantain) for their nutritional and functional properties. For all GF flours investigated, starch was the major component, except for gram, chickpea, and tiger nut flours with lower starch content (<45%), but higher fiber content (8.8–35.4%). The higher amount of calcium, magnesium, zinc, potassium, phosphorus, similar values for iron and lower content of sodium in gram, makes this flour a good alternative to chickpea or other GF flour to develop healthier food products. Amaranth flour had a high protein digestibility, while tiger nut and millet flours were less digestible. Gram, chickpea, quinoa, buckwheat, and oat flours fulfilled amino acids recommendation for daily adult intake showing no limiting amino acid. Total polyphenolic content and antioxidant capacity showed higher values for buckwheat, followed by quinoa and maize flours. Gram, chickpea, maize, and quinoa flours are good candidates to improve health conditions due to lower saturated fatty acid content. The findings of this study provide useful insights into GF flours and may contribute to the development of novel gluten-free products like bread, cookies, or pasta.

The present study presents the use of photochemiluminescence assay (PCL) and 2,2 diphenyl-1-picryl-hydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), the ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods for the measurement of lipid-soluble antioxidant capacity (ACL) of 14 different byproducts obtained from the vegetable oil industry (flour, meals, and groats). The research showed that the analyzed samples contain significant amounts of phenolic compounds between 1.54 and 74.85 mg gallic acid per gram of byproduct. Grape seed flour extract had the highest content of total phenolic compounds, 74.85 mg GAE/g, while the lowest level was obtained for the sunflower groats, 1.54 mg GAE/g. DPPH values varied between 7.58 and 7182.53 mg Trolox/g of byproduct, and the highest antioxidant capacity corresponded to the grape seed flour (7182.53 mg Trolox/g), followed by walnut flour (1257.49 mg Trolox/g) and rapeseed meals (647.29 mg Trolox/g). Values of ABTS assay of analyzed samples were between 0 and 3500.52 mg Trolox/g of byproduct. Grape seed flour had the highest value of ABTS (3500.52 mg Trolox/g), followed by walnut flower (1423.98) and sea buckthorn flour (419.46). The highest values for FRAP method were represented by grape seed flour (4716.75 mg Trolox/g), followed by sunflower meals (1350.86 mg Trolox/g) and rapeseed flour (1034.92 mg Trolox/g). For CUPRAC assay, grape seed flour (5936.76 mg Trolox/g) and walnut flour (1202.75 mg Trolox/g) showed the highest antioxidant activity. To assess which method of determining antioxidant activity is most appropriate for the byproducts analyzed, relative antioxidant capacity index (RACI) was calculated. Depending on the RACI value of the analyzed byproducts, the rank of antioxidant capacity ranged from −209.46 (walnut flour) to 184.20 (grape seed flour). The most sensitive methods in developing RACI were FRAP (r = 0.5795) and DPPH (r = 0.5766), followed by CUPRAC (r = 0.5578) and ABTS (r = 0.4449), respectively. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and other methods used for determining antioxidant activity were found (r > 0.9). Analyses have shown that the different types of byproducts obtained from the vegetable oil industry have a high antioxidant activity rich in phenolic compounds, and thus their use in bakery products can improve their nutritional quality.

This study provides an assessment of nutrients (protein, amino acid profiles, fiber, starch), phenolic content TPC, flavonoid content TFC, and antioxidant capacity through different in vitro methods in 12 legume species (red, green, yellow, brown, and black lentils; mung, pinto, black, and kidney beans; chickpea, soy, and lupin) and hemp. Legumes with a protein content above 30% were black lentil, lupin, and soy. Chickpea, soy, black bean, kidney bean, and mung bean did not have any limiting amino acids. All samples had moderate overall protein quality, except green and brown lentils. Black bean was less digestible (68.1%), while soy, hemp, and red lentil had higher protein digestibility (79.3–84.7%). Pinto bean had the highest TPC (425.19 mg GAE/100 g), comparable with hemp, but the lowest TFC (0.24 mg QE/100 g). Yellow and red lentils showed the lowest TPC (69–85.89 mg GAE/100 g). Mung bean presented the highest concentration of flavonoids (45.47 mg QE/100 g), followed by black lentil (28.57 mg QE/100 g). There were distinct variations in the antioxidant capacity across different legume samples and assays. Pinto bean, hemp, and green lentil had the highest relative antioxidant capacity index, while yellow lentil, red lentil, and chickpea presented the lowest. Dark-colored legume samples showed a higher TPC and a lower antioxidant capacity (CUPRAC and PCL assays), while yellow legumes had less antioxidant capacity (DPPH assay). A high correlation coefficient was observed between TPC and DPPH (r = 0.8133), TPC and FRAP (r = 0.8528), TPC and CUPRAC (r = 0.9425), and TPC and ACL (r = 0.8261) methods. The results highlight large variations in the legume properties and support the exploitation of the nutritional properties of legumes as raw materials for the development of products designed to fulfil modern consumer demands.

The by-product resulting from the production of the sea-buckthorn (Hippophae rhamnoides) juice may be a functional food ingredient, being a valuable source of bioactive compounds, such as polyphenols, flavonoids, minerals, and fatty acids. For checking this hypothesis, two extracts were obtained by two different methods using 50% ethyl alcohol solvent, namely through maceration–recirculation (E-SBM) and through ultrasound extraction (E-SBUS), followed by concentration. Next, sea-buckthorn waste (SB sample), extracts (E-SBM and E-SBUS samples) and the residues obtained from the extractions (R-SBM and R-SBUS samples) were characterized for the total polyphenols, flavonoid content, antioxidant capacity, mineral contents, and fatty acids profile. The results show that polyphenols and flavonoids were extracted better by the ultrasound process than the other methods. Additionally, the antioxidant activity of the E-SBUS sample was 91% higher (expressed in Trolox equivalents) and approximately 45% higher (expressed in Fe²⁺ equivalents) than that of the E-SBM sample. Regarding the extraction of minerals, it was found that both concentrated extracts had almost 25% of the RDI value of K and Mg, and also that the content of Zn, Mn, and Fe is significant. Additionally, it was found that the residues (R-SBM and R-SBUS) contain important quantities of Zn, Cu, Mn, Ca, and Fe. The general conclusion is that using the ultrasound extraction method, followed by a process of concentrating the extract, a superior recovery of sea-buckthorn by-product resulting from the juice extraction can be achieved.

The objective of this study was to evaluate the effects of different types of powder additions on the properties of corn extrudates. The following ingredients, which are good sources of bioactive compounds, were used to substitute corn flour: legume protein sources (2% pea, 5% broccoli, and 5% lucerne), plants (15% beetroot and 15% rosehip), and condiments (2% chili, 2% turmeric, 2% paprika, and 2% basil). The total polyphenolic content (TPC) and antioxidant activity (AA) increased when the corn flour was replaced with the different types of ingredients. The highest TPC was found for rosehip followed by the beet, basil, and broccoli additions. Compared to the raw formulations, all the extrudates, except the rosehip extrudate, showed a decrease in the TPC ranging from 11 to 41%, with the smallest loss (11%) occurring for basil and the highest loss (41%) occurring for the control extrudate, respectively. The same observation was recorded for the AA. For the extrudate enriched with rosehip, the TPC and AA increased by 20% and 16%, respectively. The highest level of protein digestibility was in the corn extrudate with the pea addition followed by broccoli and lucerne. The extruded corn samples with condiment additions had a lower glycemic index than the control extrudate. This study demonstrated the potential for the production of gluten-free corn extrudates enriched with ingredients from different sources with improved nutritional properties, conferring also a natural color in the final extrudates.

The current consumption trends of plant based functional products have encouraged researchers and industry to study the production of protein enriched bakery products as a source of protein. In the context of the circular economy, the press cakes remaining after extraction of juices/oil from plants such as sea buckthorn or hemp can be valorized as they are rich in proteins, fibers and many bioactive compounds. Their use in bread making is a good solution to enrich the nutritional value of bread. Pea protein concentrate, hemp and sea buckthorn ingredients from press cakes by-products were added to whole wheat flour in different percentages and combinations (2% pea protein concentrate; 1% pea + 2% sea buckthorn ingredients; 1% pea + 2% hemp ingredients). Bread samples were obtained through three technological methods: one phase baking process (dough), two phases (sponge and dough) and one phase with dried sourdough added directly into the dough. A control sample (100% wheat whole flour) was considered. The mixtures of whole wheat flour and plant protein ingredients were rheologically tested. The bread samples were physicochemically analyzed (protein, fat, carbohydrates, energy value) and sensory characteristics were evaluated (texture, color and overall acceptability). The changes in the physicochemical characteristics, rheology behavior, microstructure and sensory quality were evaluated and compared. The energy from protein varied from 17.26 to 19.34% which means that all the samples can be considered “a source of protein”. Hardness decreased in samples with sponge and dried sourdough which reflect the importance of technology in keeping the freshness of the product. The most appreciated were the samples with pea protein concentrate, with hemp ingredient obtained through an indirect bread making process and the sample with sea buckthorn ingredient prepared through a direct bread making process using dried sourdough.