In vivo protein quality of selected cereal-based staple foods enriched with soybean proteins

Background: One way to diminish protein malnutrition in children is by enriching cereal-based flours for the manufacturing of maize tortillas, wheat flour tortillas, and yeast-leavened breads, which are widely consumed among low socio-economic groups. Objective: The aim was to determine and compare the essential amino acid (EAA) scores, protein digestibility corrected amino acid scores (PDCAAS), and in vivo protein quality (protein digestibility, protein efficiency ratio (PER), biological values (BV), and net protein utilization (NPU) values) of regular versus soybean-fortified maize tortillas, yeast-leavened bread, and wheat flour tortillas. Design: To comparatively assess differences in protein quality among maize tortillas, wheat flour tortillas, and yeast-leavened breads, EAA compositions and in vivo studies with weanling rats were performed. The experimental diets based on regular or soybean-fortified food products were compared with a casein-based diet. Food intake, weight gains, PER, dry matter and protein digestibility, BV, NPU, and PDCAAS were assessed. The soybean-fortified tortillas contained 6% of defatted soybean flour, whereas the yeast-leavened bread flour contained 4.5% of soybean concentrate. Results: The soybean-fortified tortillas and bread contained higher amounts of lysine and tryptophan, which improved their EAA scores and PDCAAS. Rats fed diets based on soybean-fortified maize or wheat tortillas gained considerably more weight and had better BV and NPU values compared with counterparts fed with respective regular products. As a result, fortified maize tortillas and wheat flour tortillas improved PER from 0.73 to 1.64 and 0.69 to 1.77, respectively. The PER improvement was not as evident in rats fed the enriched yeast-leavened bread because the formulation contained sugar that decreased lysine availability possibly to Maillard reactions. Conclusions: The proposed enrichment of cereal-based foods with soybean proteins greatly improved PDCAAS, animal growth, nitrogen retention, and PER primarily in both maize and wheat flour tortillas. Therefore, these foods can help to diminish protein malnutrition among children who greatly depend on cereals as the main protein dietary source

Effect of extrusion conditions and hydrolysis with fiber-degrading enzymes on the production of C5 and C6 sugars from brewers’ spent grain for bioethanol production

The bioconversion of brewers’ spent grain into bioethanol was investigated in the present study using thermoplastic extrusion and the use of fiber degrading enzymes. The extrusion conditions i.e. tempering moisture, screws speed, and temperature of last zone of the barrel were taken into account in order to optimize the yield of C5 and C6 sugars during the subsequent enzymatic hydrolysis step of the fibers. The most important variable that affected the sugar yield was the extrusion temperature, followed by the screws speed. The best extrusion conditions were 20% tempering moisture, 200 rpm and 50 °C. No enzymatic and yeast inhibitors were detected in any of the enzymatically-treated fiber hydrolyzates. The fermentation resulted in 5.43 mL bioethanol per 100g of extruded brewers’ spent grain (dry weight basis). The only sugar consumed was glucose. The free amino nitrogen amount quantified in the hydrolyzates was as low as >20 mg L-1, negatively affecting sugars consumption during the fermentation and consequently the ethanol yield

Comparison of Physicochemical, Functional and Nutritional Properties between Proteins of Soybean and a Novel Mixture of Soybean-Maize

Vegetable proteins are potential low-cost alternatives to solve the protein deficiency of the world population. A protein extracted from a mixture of soybean meal and maize germ was developed to offer more protein alternatives with high nutritional value. In this study, physicochemical, functional, and nutritional characteristics of isolates and hydrolysates of soybean and counterparts extracted from a soybean meal-maize germ were compared. The isolate and hydrolysate of the soybean-maize blend had a protein content of 93.9% and 73.6%, respectively. These protein mixtures contained 10% and 52% more solubility, 303.9%, and 22.7% more emulsifying capacity, 4.5% and 4.2% higher foam density and 36.3% and 1.2% more coagulation capacity compared to the soybean isolate and hydrolysate. Electrophoretic profiles of soybean-maize proteins showed four additional bands to the typical soybean pattern of 56, 55, 52 and 18 kDa, which could correspond to globulins and zeins from maize. The isolate extracted from the mixture of soybean meal and maize is a new alternative to provide the necessary amino acids for proper physical and mental development. Additionally, it has a high potential to be used as an ingredient by the food industry due to its excellent functionality and nutritional value

Mimicking gluten functionality with β-conglycinin concentrate: Evaluation in gluten free yeast-leavened breads

Fractionation of soy proteins has proved to produce protein concentrates with viscoelastic properties. In the present study, a β-conglycinin concentrate (βCC) obtained by a pH fractionation of soy flour was tested as structuring agent in gluten-free yeast-leavened bread model. A lean formulation with βCC and corn starch was used to produce gluten-free breads with two hydration conditions and three levels of protein (5%, 10% and 15%). Vital gluten was used to compare the functionality of βCC protein and its performance for breadmaking. Breads were characterized in moisture, color, textural parameters and image analysis. βCC presented lower hydration properties and higher emulsifying activity compared to vital gluten. Blends βCC:starch had higher water binding capacity compared to vital gluten blends. The hydration conditions tested affected the moisture, color and cell density of breads. Breads produced with βCC presented higher 2D area and height and presented higher crumb softness and cohesiveness, and did not present significant differences in springiness and resilience compared to vital gluten breads. The image analysis of crumbs showed higher cell density but lower porosity and mean cell areas in βCC breads. Thus, βCC proved to have potential as a structuring agent in gluten-free breads.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), Generalitat Valenciana (Project Prometeo 2017/189), the European Regional Development Fund (FEDER) and the joint project between research group from IATA-CSIC and the research groups of Nutriomics and CIDPRO from Tecnologico de Monterrey. Johanan Espinosa-Ramírez acknowledges the support from CONACyT for the PhD scholarship (375643).Peer reviewe

Functional and nutritional replacement of gluten in gluten-free yeast-leavened breads by using β-conglycinin concentrate extracted from soybean flour

The search of proteins that could act as both structural agents and nutritional enhancers in gluten free bread is still a challenge for the food industry. The present study evaluated the inclusion of 10% β-conglycinin concentrate (βCC) extracted from defatted soybean flour to rice flour to improve the structure and protein quality of gluten-free yeast-leavened bread. βCC breadmaking performance was compared to vital gluten functionality. Batter pasting properties and bread characterization in terms of color, texture, image analysis, microstructure a, nd protein quality were assessed. βCC and gluten led to batters with higher peak viscosity and breakdown, although only βCC was able to increase the setback. The inclusion of 10% βCC in rice flour formulations led to breads with improved color parameters and protein quality. The texture properties of βCC breads did not present significant differences compared to vital gluten breads. The crumb analysis showed that βCC led to lower cell density with highest mean cell area. The micrographs showed that βCC was able to create a net-like structure similar to the one created by gluten, confirming that βCC is capable of acting as structuring agent and protein quality improver in gluten-free formulations.Authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R), Generalitat Valenciana (Project Prometeo 2017/189), the European Regional Development Fund and the joint project between research group from IATA-CSIC and the research groups of Nutriomics and CIDPRO from Tecnologico de Monterrey, Mexico. Johanan Espinosa-Ramírez acknowledges the support from CONACYT for the PhD scholarship (375643).Peer reviewe

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity. Therefore, it is important to incorporate flavonoids derived from natural sources in several products such as foods, cosmetics, and drugs. For this reason, there is currently a need to extract flavonoids from plant resources. In this review are described the most important parameters involved in the extraction of flavonoids by unconventional methods such as ultrasound, pressurized liquid extraction, mechanochemical, high hydrostatic pressure, supercritical fluid, negative pressure cavitation, intensification of vaporization by decompression to the vacuum, microwave, infrared, pulsed electric field, high-voltage electrical discharges, and enzyme-assisted extraction. There are no unified operation conditions to achieve high yields and purity. Notwithstanding, progress has been achieved in the development of more advanced and environmentally friendly methods of extraction. Although in literature are found important advances, a complete understanding of the extraction process in each of the unconventional techniques is needed to determine the thermodynamic and kinetic mechanisms that govern each of the techniques

Influence of Excipients and Spray Drying on the Physical and Chemical Properties of Nutraceutical Capsules Containing Phytochemicals from Black Bean Extract

Black beans (Phaseolus vulgaris L.) are a rich source of flavonoids and saponins with proven health benefits. Spray dried black bean extract powders were used in different formulations for the production of nutraceutical capsules with reduced batch-to-batch weight variability. Factorial designs were used to find an adequate maltodextrin-extract ratio for the spray-drying process to produce black bean extract powders. Several flowability properties were used to determine composite flow index of produced powders. Powder containing 6% maltodextrin had the highest yield (78.6%) and the best recovery of flavonoids and saponins (>56% and >73%, respectively). The new complexes formed by the interaction of black bean powder with maltodextrin, microcrystalline cellulose 50 and starch exhibited not only bigger particles, but also a rougher structure than using only maltodextrin and starch as excipients. A drying process prior to capsule production improved powder flowability, increasing capsule weight and reducing variability. The formulation containing 25.0% of maltodextrin, 24.1% of microcrystalline cellulose 50, 50% of starch and 0.9% of magnesium stearate produced capsules with less than 2.5% weight variability. The spray drying technique is a feasible technique to produce good flow extract powders containing valuable phytochemicals and low cost excipients to reduce the end-product variability