High-pressure microfluidisation positively impacts structural properties and improves functional characteristics of almond proteins obtained from almond meal

Almond protein isolate (API) obtained from almond meal was processed using dynamic high-pressure microfluidisation (0, 40, 80, 120, and 160 MPa pressure; single pass). Microfluidisation caused significant reductions in the particle size and increased absolute zeta potential. SDS-PAGE analysis indicated reduction in band intensity and the complete disappearance of bands beyond 80 MPa. Structural analysis (by circular dichroism, UV-Vis, and intrinsic-fluorescence spectra) of the API revealed disaggregation (up to 80 MPa) and then re-aggregation beyond 80 MPa. Significant increments in protein digestibility (1.16-fold) and the protein digestibility corrected amino acid score (PDCAAS; 1.15-fold) were observed for the API (80 MPa) than control. Furthermore, significant improvements (P < 0.05) in the functional properties were observed, viz., the antioxidant activity, protein solubility, and emulsifying properties. Overall, the results revealed that moderate microfluidisation treatment (80 MPa) is an effective and sustainable technique for enhancing physico-chemical and functional attributes of API, thus potentially enabling its functional food/nutraceuticals application.

Perspective: Developing a Nutrient-Based Framework for Protein Quality

The future of precision nutrition requires treating amino acids as essential nutrients. Currently, recognition of essential amino acid requirements is embedded within a generalized measure of protein quality known as the PDCAAS (Protein Digestibility-Corrected Amino Acid Score). Calculating the PDCAAS includes the FAO/WHO/UNU amino acid score, which is based on the limiting amino acid in a food, that is, the single amino acid with the lowest concentration compared to the reference standard. That "limiting" amino acid score is then multiplied by a bioavailability factor to obtain the PDCAAS, which ranks proteins from 0.0 (poor quality) to 1.0 (high quality). However, the PDCAAS has multiple limitations: it only allows for direct protein quality comparison between 2 proteins, and it is not scalable, transparent, or additive. We therefore propose that shifting the protein quality evaluation paradigm from the current generalized perspective to a precision nutrition focus treating amino acids as unique, metabolically active nutrients will be valuable for multiple areas of science and public health. We report the development and validation of the Essential Amino Acid 9 (EAA-9) score, an innovative, nutrient-based protein quality scoring framework. EAA-9 scores can be used to ensure that dietary recommendations for each essential amino acid are met. The EAA-9 scoring framework also offers the advantages of being additive and, perhaps most importantly, allows for personalization of essential amino acid needs based on age or metabolic conditions. Comparisons of the EAA-9 score with PDCAAS demonstrated the validity of the EAA-9 framework, and practical applications demonstrated that the EAA-9 framework is a powerful tool for precision nutrition applications.

Plant Proteins: Methods of Quality Assessment and the Human Health Benefits of Pulses

As countries increase their standard of living and individual income levels rise, there is a concomitant increase in the demand for animal-based protein. However, there are alternative sources. One of the alternatives available is that of increased direct human consumption of plant proteins. The quality of a dietary protein is an important consideration when discussing the merits of one protein source over another. The three most commonly used methods to express protein quality are the protein efficiency ratio (PER), a weight gain measurement; protein digestibility-corrected amino acid score (PDCAAS); and the digestible indispensable amino acid score (DIAAS). The possibility that alterations in the quality and quantity of protein in the diet could generate specific health outcomes is one being actively researched. Plant-based proteins may have additional beneficial properties for human health when compared to animal protein sources, including reductions in risk factors for cardiovascular disease and contributions to increased satiety. In this paper, the methods for the determination of protein quality and the potential beneficial qualities of plant proteins to human health will be described.

Nutritional assessment of nixtamalized maize tortillas produced from dry masa flour, landraces, and high yield hybrids and varieties

In the scientific literature there are different analyses of the nutritional profiles of maize tortillas, whether they are landraces or hybrid maize versus those made with dry masa flour (DMF). In general terms, there is agreement in the reported content of moisture. However, for the other nutrients, a great disparity is reported for each type of tortilla which may be due to various factors such as the type of maize or processing methods. In this study, the nutritional aspects of maize tortillas made with different genotypes (five hybrids, two varieties, five landraces, six hybrid mixtures and six dry masa flours) under controlled conditions, were compared. More than 30 characteristics were analyzed. High performance hybrids and varieties (HPHV) and landraces had the highest (p < 0.05) antioxidant capacity (58.8% free, 150.2% bound). In terms of vitamins contents, the tortillas produced from DMF contained 11.2 and 3.5 times more B1, 18.6 and 7.8 times more B2, and 2.7 and 5.3 times more B3 than HPHV and landraces respectively; and only in these samples was detected folic acid. DMF tortilla samples contained 1.75 times more sodium and 2.75 times more iron than the other groups, and 0.75 times less calcium than HPHV. Zinc was present in higher concentration (p < 0.05) in DMF tortilla samples. The landraces had the highest protein content (average 10.28%), but the tortillas produced from DMF presented the highest protein quality evaluated by protein digestibility-corrected amino acid score (PDCAAS) (p < 0.05) that represents 27, 25 and 19% more than hybrids mixture, HPHV and landraces, respectively. This work gives valuable information on how different types of grains differ in the nutritional quality affecting the final product to provide more elements in the decision-making of processors. There is no a perfect maize, but there are genotypes that can be combined as mixtures and the processing method to design superior nutritional tortillas and related products for populations that highly consume them and improve their human health.

Fermented Whey Ewe's Milk-Based Fruit Smoothies: Bio-Recycling and Enrichment of Phenolic Compounds and Improvement of Protein Digestibility and Antioxidant Activity

This study aimed to recycle whey milk by-products (protein source) in fruit smoothies (phenolic compounds source) through started-assisted fermentation and delivering sustainable and healthy food formulations capable of providing nutrients that are unavailable due to an unbalanced diet or incorrect eating habits. Five lactic acid bacteria strains were selected as best starters for smoothie production based on the complementarity of pro-technological (kinetics of growth and acidification) traits, exopolysaccharides and phenolics release, and antioxidant activity enhancement. Compared to raw whey milk-based fruit smoothies (Raw_WFS), fermentation led to distinct profiles of sugars (glucose, fructose, mannitol, and sucrose), organic acids (lactic acid and acetic acid), ascorbic acid, phenolic compounds (gallic acid, 3-hydroxybenzoic acid, chlorogenic acid, hydrocaffeic acid, quercetin, epicatechin, procyanidin B2, and ellagic acid) and especially anthocyanins (cyanidin, delphinidin, malvidin, peonidin, petunidin 3-glucoside). Protein and phenolics interaction enhanced the release of anthocyanins, notably under the action of Lactiplantibacillus plantarum. The same bacterial strains outperformed other species in terms of protein digestibility and quality. With variations among starters culture, bio-converted metabolites were most likely responsible for the increase antioxidant scavenging capacity (DPPH, ABTS, and lipid peroxidation) and the modifications in organoleptic properties (aroma and flavor).

Effect of increasing plant protein intake on protein quality and nutrient intake of US adults

Three cycles of NHANES (2013-2018) were used to assess protein intake, protein quality (protein digestibility-corrected amino acid score; PDCAAS), protein cost, and nutrient intakes across quartiles of plant protein intake (Q1: <28.2%; Q2: 28.2% to <32.1%; Q3: 32.1 to <36.2%; Q4: ≥36.2%) over a 24 h period (≥19 years, n = 14 888). Grains represented the primary source of plant protein across quartiles and increased from 5.01% (Q1) to 13.5% (Q4). Across all the USDA's Food and Nutrient Database for Dietary Studies (FNDDS) food groups, grains were the most economical source of protein (24.3-26 g protein/$1). Legumes were the most economical plant-based protein (28-37.7 g protein/$1) within the "Protein Foods" FNDDS group. Absolute protein intake (96.6 g/day) and PDCAAS (0.91) of diets were progressively lower from Q1 to 72.0 g/day and 0.8 in Q4, respectively. Modelling the replacement of 50% of amino acids from grains in the diet with amino acids from legumes increased the PDCAAS by 10% in Q4. Intake levels of fibre, folate, iron, and zinc, were higher in Q2-Q4 compared to Q1 but had lower intakes of vitamins B12 and D. Amino acid complementation is required to effectively integrate higher levels plant protein into US diets.

Seaweed proteins are nutritionally valuable components in the human diet

The global population is expected to reach 11 billion people by the year 2100 and will require sustainable sources of dietary protein. Most dietary protein originates from animal and terrestrial plant agriculture, which leads to deforestation, water pollution, and greenhouse gas emissions. Discovering alternative protein sources that are nutritionally adequate for the human diet without harmful environmental effects is imperative. Seaweeds are a promising option as they produce abundant protein with a low carbon footprint. Experimental evidence shows that seaweeds contain high concentrations of the essential amino acids (EAAs) necessary for human consumption, but seaweeds have yet to be evaluated with standardized metrics to compare their nutritional value to other protein sources. In this technical note, independent literature describing the EAA content and protein digestibility of 3 commonly consumed species of seaweeds was evaluated alongside traditional protein sources using a novel hybrid protein quality (HPQ) metric. HPQ is derived from the protein digestibility-corrected amino acid score and digestibility indispensable amino acid score but includes modifications to address the lack of in vivo digestibility data for seaweeds. Seaweed proteins are similar in quality to common plant protein sources such as peas, soy, and tree nuts. Furthermore, seaweed proteins from different species have complementary EAA profiles and can be mixed to form protein blends that are nutritionally on par with animal products such as milk and whey. Thus, seaweeds may be viable protein sources with a reduced footprint that provide beneficial ecosystem services.

Extraction and Characterization of Protein Concentrates from Limpets (Patella vulgata) and Peptide Release Following Gastrointestinal Digestion

This study investigated the characterization of proteins from the Irish limpet (Patella vulgata) and assessed the in vitro biological activities of hydrolysates obtained following gastrointestinal digestion (INFOGEST) of a limpet protein concentrate (LPC). The physicochemical properties and the digestibility of the LPC were investigated, along with the angiotensin-converting enzyme (ACE) inhibition and antioxidant activities of the LPC-digested samples. All the digested samples examined outperformed the LPC in terms of activity. Peptides were identified using LC-MS/MS after digestion. A total of 38 and 19 peptides were identified in LPC-G and LPC-GI, respectively, using a database search and a de novo approach. Most of the identified peptides had hydrophobic amino acids, which may contribute to their antioxidant and ACE inhibitory activities. The findings of this study showed that LPC has high nutritional quality with good digestibility and could serve as a potential source of antioxidative and ACE inhibitory peptides following gastrointestinal digestion.

Effects of the substitution of wheat flour with raw or germinated ayocote bean (Phaseolus coccineus) flour on the nutritional properties and quality of bread

This study aimed to evaluate the potential of 10%, 20%, and 30% of raw (ARF) and germinated (AGF) ayocote bean flour as a partial substitute for wheat flour in breadmaking. Substitution with both ayocote bean flours modified the water absorption and development time while maintaining the dough stability. Supplemented breads had 13%, 51%, and 132% higher protein, mineral, and crude fiber content, respectively, than control bread (100% wheat). The breadmaking features, color and crumb firmness, were affected by the substitution level. Sensory analysis revealed that germination could improve the taste and smell of breads produced with ayocote bean flour. The sensory attribute scores of 10% AGF bread were comparable to those of the control bread. Supplementation reduced the in vitro protein digestibility, although the effect was less pronounced in 10% ARF and 20% AGF breads. The limiting amino acid score of supplemented breads increased up to 70%, which improved their protein digestibility-corrected amino acid scores. Supplementation with 20% or 30% of both ARF and AGF increased resistant starch values and decreased the total digestible starch of breads. Thus, the results showed that substituting wheat with ARF or AGF improves the nutritional properties of bread. However, low substitution levels should be selected to avoid a considerable decrease in physical and sensory properties. PRACTICAL APPLICATION: Substituting wheat flour with ayocote bean flour improved the nutritional value of bread. Germination of ayocote beans decreased the cooking stability of composite dough. Bread fortified with ayocote flour had high levels of essential amino acids. Bread with raw or germinated ayocote flours had high limiting amino acid scores. Composite bread had high resistant starch and low total digestible starch.

Ready-to-Use Therapeutic Food (RUTF) Containing Low or No Dairy Compared to Standard RUTF for Children with Severe Acute Malnutrition: A Systematic Review and Meta-Analysis

Ready-to-use therapeutic food (RUTF) containing less dairy may be a lower-cost treatment option for severe acute malnutrition (SAM). The objective was to understand the effectiveness of RUTF containing alternative sources of protein (nondairy), or <50% of protein from dairy products, compared with standard RUTF in children with SAM. The Cochrane Library, MEDLINE, Embase, CINAHL, and Web of Science were searched using terms relating to RUTF. Studies were eligible if they included children with SAM and evaluated RUTF with <50% of protein from dairy products compared with standard RUTF. Meta-analysis and meta-regression were completed to assess the effectiveness of intervention RUTF on a range of child outcomes. The quality of the evidence across outcomes was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. A total of 5868 studies were identified, of which 8 articles of 6 studies met the inclusion criteria evaluating 7 different intervention RUTF recipes. Nondairy or lower-dairy RUTF showed less weight gain (standardized mean difference: -0.20; 95% CI: -0.26, -0.15; P < 0.001), lower recovery (relative risk ratio: 0.93; 95% CI: 0.87, 1.00; P = 0.046), and lower weight-for-age z scores (WAZ) near program discharge (mean difference: -0.10; 95% CI: -0.20, 0.0; P = 0.047). Mortality, time to recovery, default (consecutive absences from outpatient therapeutic feeding program visits), nonresponse, and other anthropometric measures did not differ between groups. The certainty of evidence was high for weight gain and ranged from very low to moderate for other outcomes. RUTF with lower protein from dairy or dairy-free RUTF may not be as effective as standard RUTF for treatment of children with SAM based on weight gain, recovery, and WAZ evaluated using meta-analysis, although further research is required to explore the potential of alternative formulations. This review was registered at https://www.crd.york.ac.uk/prospero/ as CRD42020160762.

Brief Research Report: Estimation of the Protein Digestibility-Corrected Amino Acid Score of Defatted Walnuts

Introduction: Walnuts are considered a good source of essential fatty acids, which is unique among tree nuts. Walnuts are also composed of about 10–15% protein, but the quality of this protein has not been evaluated. Pistachios and almonds have been evaluated for their protein content using a protein digestibility-corrected amino acid score (PDCAAS), but it is unclear how the quality of protein in walnuts relates to that in other commonly consumed tree nuts. The objective of this study was to substantiate the protein quality of walnuts by determining their PDCAAS.

Methods: A small, 10-day dietary intervention trial was conducted using male Sprague-Dawley rats (n = 8, 4 per group) with two diets: a nitrogen-free diet and a diet containing protein exclusively from defatted walnuts. Feed intake and fecal output of nitrogen were measured to estimate the true protein digestibility, and the amino acid compositions of walnuts compared to child and adult populations were used to calculate amino acid scores (AAS) and PDCAAS.

Results: The true protein digestibility score of raw walnuts was calculated to be 86.22%. Raw walnuts contained 15.6 g protein/g walnut with AAS of 0.45 and 0.63 for children aged 6 months to 3 years and 3–10 years, respectively. For each population, a PDCAAS of 39 and 46% was calculated, respectively, using a protein conversion constant of 5.30. Using a protein constant of 6.25, a PDCAAS of 39% (6 months - 3 years) or 46% (3-10 years) was calculated.

Conclusions: This is the first known assessment of the PDCAAS of walnuts. Like almonds, they appear to have a low-to-moderate score, indicating they are not a quality source of protein.

Limitations with the Digestible Indispensable Amino Acid Score (DIAAS) with Special Attention to Plant-Based Diets: a Review

PURPOSE OF REVIEW

This review describes several limitations of the Digestible Indispensable Amino Acid Score (DIAAS) with a focus on its application to plant-based dietary patterns.

RECENT FINDINGS

Evaluating protein quality in terms of digestibility is paramount to support and optimize the health and well-being of human populations in situations where food insecurity and protein energy malnutrition are widespread. The Food and Agriculture Organization (FAO) of the United Nations has endorsed the DIAAS to replace the previously recommended Protein Digestibility Corrected Amino Acid Score (PDCAAS) for protein quality assessment. While multiple strengths characterize the DIAAS, substantial limitations remain, many of which are accentuated in the context of a plant-based dietary pattern. Some of these limitations include a failure to translate differences in nitrogen-to-protein conversion factors between plant- and animal-based foods, limited representation of commonly consumed plant-based foods within the scoring framework, inadequate recognition of the increased digestibility of commonly consumed heat-treated and processed plant-based foods, its formulation centered on fast-growing animal models rather than humans, and a focus on individual isolated foods vs the food matrix. The DIAAS is also increasingly being used out of context where its application could produce erroneous results such as exercise settings. When investigating protein quality, particularly in a plant-based dietary context, the DIAAS should ideally be avoided.

Adjusting for protein quality by food source may affect nutrient density metrics

Methods to assess nutrient density of foods, commonly known as nutrient profiling (NP), typically include protein as a component. In this study, the goal was to apply a correction for protein quality by food source to selected NP algorithms. Analyses of 378 component foods of the Fred Hutch food frequency questionnaire showed that animal-source foods (ie, meat, eggs, and dairy) along with some soy products and nuts were the only foods that provided > 20% of the daily value (DV) of protein per 100 g or per 100 kcal. Most beans, pulses, legumes, grains, and vegetables provided <10% DV of protein per 100 g or per 100 kcal. Adjusting for protein quality using a simplified Protein Digestibility Corrected Amino Acid Score (PDCAAS) had consequences for point-based NP models (namely, Nutri-Score) and for continuous nutrient density scores (namely, Nutrient Rich Foods). Quantitative methods that use protein content to capture nutrient density may require a protein-quality adjustment, especially when adapted for use in low- and middle-income countries where protein quality is an issue of public health concern.

Plant Proteins: Assessing Their Nutritional Quality and Effects on Health and Physical Function

Consumer demand for plant protein-based products is high and expected to grow considerably in the next decade. Factors contributing to the rise in popularity of plant proteins include: (1) potential health benefits associated with increased intake of plant-based diets; (2) consumer concerns regarding adverse health effects of consuming diets high in animal protein (e.g., increased saturated fat); (3) increased consumer recognition of the need to improve the environmental sustainability of food production; (4) ethical issues regarding the treatment of animals; and (5) general consumer view of protein as a "positive" nutrient (more is better). While there are health and physical function benefits of diets higher in plant-based protein, the nutritional quality of plant proteins may be inferior in some respects relative to animal proteins. This review highlights the nutritional quality of plant proteins and strategies for wisely using them to meet amino acid requirements. In addition, a summary of studies evaluating the potential benefits of plant proteins for both health and physical function is provided. Finally, potential safety issues associated with increased intake of plant proteins are addressed.

Comparative study of innovative blends prepared by fortification of date powder to alleviate child malnutrition

Child malnutrition is one of the biggest problems in developing countries with higher level of food insecurity. Pakistan is 5th largest producer of date fruit; therefore, its processing and products should be explored in various dimensions. Being rich source of minerals and sugars, it can contribute in weaning foods in a good manner. In current study, three blends were prepared with specific proportions of spray-dried date powder and rich in specific proportions. They were compared with each other and control (free of date powder). The nutritional profile of the formulations revealed that 100 g of each formulation included all macronutrients in compliance with the requirements of Food and Agriculture Organization for weaning formulations; moreover, they are enriched with minerals due to presence of date powder. The iron contents reached up to 12.74 ± 0.16 mg/100 g. The phosphorus, zinc, and potassium contents also increased with the increase in date powder subsequently. Physicochemical properties exhibited in compliance with the requirement of the weaning foods. The protein quality was assessed both in vivo and in vitro. Amino acid profiling indicated that the limiting amino acid in F1 and control were lysine but in F2 and F3 were threonine. This is suggested that date powder might contain good quality protein that was further explained in biological studies, the formulations that contained higher amount of date powder reveled better PDCAAS score 86.76 ± 4.5, true digestibility 84 ± 4.36, biological value 69.45 ± 0.69, net protein utilization 73.82 ± 1.46, and protein efficiency score 1.18 ± 0.07. The sensory evaluation revealed that F2 showed better result in overall acceptability. Thus, date powder is suggested to be used as good constituent that can fortify mineral contents and sugar contents of the weaning foods.

Comparison of methodologies used to define the protein quality of human foods and support regulatory claims

Protein quality (PQ) is the capacity of a protein to meet the amino acid (AA) requirements of an individual. There are several methodologies for determining the PQ of foods. The protein efficiency ratio is an animal growth bioassay. The protein-digestibility-corrected AA score considers the AA requirements of a reference population, and the true nitrogen digestibility coefficient for each ingredient. The digestible indispensable AA score is based on true ileal AA digestibility and better represents bioavailability of AAs. In vitro techniques for assessment of PQ are available but require validation against a greater range of protein sources. Isotopic methods, such as the indicator AA oxidation and dual tracer techniques measure AA relative bioavailability and digestibility, respectively, but require sophisticated equipment, and may not be cost nor time effective for the industry to adopt. The present review discusses advantages and disadvantages of methodologies for determining PQ of food for humans focused on methods that are or could be adopted by regulatory agencies. Understanding the framework and resources available for PQ determination will help in the selection of appropriate methods depending on the application. Novelty Understanding the framework and resources available for PQ determination will help in the selection of appropriate methods depending on the application.

Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance

The results of twenty years of research indicate that the inclusion of collagen peptides in the diet can lead to various improvements in health. According to the current protein quality evaluation method PDCAAS (Protein Digestibility-corrected Amino Acid Score), collagen protein lacks one indispensable amino acid (tryptophan) and is therefore categorized as an incomplete protein source. Collagen protein displays a low indispensable amino acid profile, yet as a functional food, collagen is a source of physiologically active peptides and conditionally indispensable amino acids that have the potential to optimize health and address physiological needs posed by aging and exercise. The objective of this study was to determine the maximum level of dietary collagen peptides that can be incorporated in the Western pattern diet while maintaining its indispensable amino acid balance. Iterative PDCAAS calculations showed that a level as high as 36% of collagen peptides can be used as protein substitution in the daily diet while ensuring indispensable amino acid requirements are met. This study suggests that the effective amounts of functional collagen peptides (2.5 to 15 g per day) observed in the literature are below the maximum level of collagen that may be incorporated in the standard American diet.

Consumption of Animal-Source Protein is Associated with Improved Height-for-Age z Scores in Rural Malawian Children Aged 12⁻36 Months

Linear growth faltering, caused by insufficient diet, recurrent infections and environmental enteric dysfunction (EED), continues to plague young children in low- and middle-income countries (LMICs). Diets in LMICs are primarily plant based, and thus have poor-quality protein and low levels of essential micronutrients. The aim of this study was to assess the association of the type and protein quality of food consumed with stunting, EED and acute malnutrition in children aged 6–36 months in Limera and Masenjere, two rural Southern Malawian communities. This is a secondary analysis of two randomized controlled trials that tested the effects of common bean and cowpea flour on stunting in children aged 6–36 months. We used data from two interactive 24-h dietary recalls conducted 12 weeks after enrolment into each trial. Food intakes were compared between the regions using Chi-square and Student’s t-test. There were 355 children that participated in the dietary recalls. The diets of children were of poor quality, but the children from Limera consumed more fish (54% vs. 35%, p = 0.009) and more bioavailable protein (26.0 ± 10.3 g/day vs. 23.1 ± 8.1 g/day, p = 0.018, respectively) than children in Masenjere. Food type and protein quality were not associated with any of the outcomes except an association between animal protein consumption and improvement in height-for-age z scores in children aged 12–36 months (p = 0.047). These findings support the notion that animal-source food (ASF) consumption in this vulnerable population promotes linear growth.

Potential impact of the digestible indispensable amino acid score as a measure of protein quality on dietary regulations and health

Regulatory frameworks for protein content claims in Canada and the United States are underpinned by the protein efficiency ratio and protein digestibility-corrected amino acid score (PDCAAS), respectively, which are used to assess the protein quality of a given food. The digestible indispensable amino acid score (DIAAS) is a novel approach to measuring the protein quality of foods and is supported by the Food and Agriculture Organization of the United Nations. Methodological concerns about the PDCAAS are addressed by the DIAAS through introduction of the use of ileal amino acid digestibility coefficients and untruncated protein scores. However, before the DIAAS is widely adopted within regulatory frameworks, a comprehensive assessment is required. Accordingly, this review addresses the potential impact of the DIAAS on regulation, communication, and public health, as well as knowledge gaps, analytical challenges, and cost of implementation. A pragmatic approach to addressing protein quality is advocated by suggesting the use of conservative coefficients of digestibility that are derived from in vitro methods. Before adopting the DIAAS as a framework for supporting protein content claims, updated food-related regulations and policies should also be evaluated through a lens that anticipates the impact on consumer-facing nutrition communication, the adoption of dietary patterns that are nutritionally adequate, and a food value chain that fosters a spirit of food and nutritional innovation.

Effect of tempering moisture and infrared heating temperature on the nutritional properties of desi chickpea and hull-less barley flours, and their blends

The impact of infrared heating surface temperature and tempering moisture on the nutritional properties of desi chickpea, hull-less barley, and their blends were examined. Specifically, this included changes to the level of anti-nutritive factors (i.e., trypsin/chymotrypsin inhibitors, total phenolics and condensed tannins), amino acid composition and in vitro protein digestibility. Results indicated that both temperature and the tempering/temperature treatment caused a reduction in levels of all anti-nutritional factors for both flours, and the effect was more prominent in the tempering-temperature combination. The amino acid composition of both flours was not substantially changed with tempering or infrared heating. The amino acid scores (AAS) of chickpea and barley flours, as determined by the first limiting amino acid using the FAO/WHO reference pattern found in the case of barley to be limiting in lysine with an AAS of ~0.9, whereas for chickpea flour, threonine was limiting and had an AAS of ~0.6. The in vitro protein digestibility of chickpea samples was found to increase from 76% to 79% with the tempering-heat (135 °C) combination, whereas barley flour increased from 72% to 79% when directly heated to 135 °C (without tempering). In vitro protein digestibility corrected amino acid score (IV-PDCAAS) was found to increase from 65% to 71% for chickpea flour and 44% to 52% for barley flour, respectively with tempering-temperature (135 °C) combination indicating that tempering with infrared heating can improve the nutritional value of both flours. The addition of chickpea flour to the barley flour acted to improve the nutritional properties (IV-PDCAAS), to an extent depending on the concentration of chickpea flour present.

Digestible indispensable amino acid score (DIAAS) and protein digestibility corrected amino acid score (PDCAAS) in oat protein concentrate measured in 20- to 30-kilogram pigs

BACKGROUND

Oat protein concentrate is often used in human food, but the quality of this protein has not been characterized. Therefore, the objectives of this experiment were to determine the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in oat protein concentrate and to determine differences in protein quality estimates between the protein digestibility-corrected AA score (PDCAAS) and the digestible indispensable AA score (DIAAS) when using growing pigs for both measurements.

RESULTS

For infants, the most limiting AA in oat protein concentrate was the aromatic AA (Phe + Tyr), for which the DIAAS value was 41 and the PDCAAS was 43. For children (6 months to 3 years) and children older than 3 years, the most limiting AA in oat protein concentrate was Lys, for which the DIAAS was 56 and 67 and the PDCAAS was 58 and 69, respectively.

CONCLUSION

The DIAAS value for oat protein concentrate was close to the calculated value for PDCAAS, but below the recommended intake for protein. Therefore, to satisfy the daily human AA requirement, oat protein needs to be complemented by other proteins of higher quality and specifically with greater lysine concentrations. © 2017 Society of Chemical Industry.

Effect of Processing on the in Vitro and in Vivo Protein Quality of Yellow and Green Split Peas (Pisum sativum)

In order to determine the effect of extrusion, baking, and cooking on the protein quality of yellow and green split peas, a rodent bioassay was conducted and compared to an in vitro method of protein quality determination. The Protein Digestibility-Corrected Amino Acid Score (PDCAAS) of green split peas (71.4%) was higher than that of yellow split peas (67.8%), on average. Similarly, the average Digestible Indispensable Amino Acid Score (DIAAS) of green split peas (69%) was higher than that of yellow split peas (67%). Cooked green pea flour had lower PDCAAS and DIAAS values (69.19% and 67%) than either extruded (73.61%, 70%) or baked (75.22%, 70%). Conversely, cooked yellow split peas had the highest PDCCAS value (69.19%), while extruded yellow split peas had the highest DIAAS value (67%). Interestingly, a strong correlation was found between in vivo and in vitro analysis of protein quality (R2 = 0.9745). This work highlights the differences between processing methods on pea protein quality and suggests that in vitro measurements of protein digestibility could be used as a surrogate for in vivo analysis.

Dietary Protein Intake in Young Children in Selected Low-Income Countries Is Generally Adequate in Relation to Estimated Requirements for Healthy Children, Except When Complementary Food Intake Is Low

Background: Previous research indicates that young children in low-income countries (LICs) generally consume greater amounts of protein than published estimates of protein requirements, but this research did not account for protein quality based on the mix of amino acids and the digestibility of ingested protein.Objective: Our objective was to estimate the prevalence of inadequate protein and amino acid intake by young children in LICs, accounting for protein quality.Methods: Seven data sets with information on dietary intake for children (6-35 mo of age) from 6 LICs (Peru, Guatemala, Ecuador, Bangladesh, Uganda, and Zambia) were reanalyzed to estimate protein and amino acid intake and assess adequacy. The protein digestibility-corrected amino acid score of each child's diet was calculated and multiplied by the original (crude) protein intake to obtain an estimate of available protein intake. Distributions of usual intake were obtained to estimate the prevalence of inadequate protein and amino acid intake for each cohort according to Estimated Average Requirements.Results: The prevalence of inadequate protein intake was highest in breastfeeding children aged 6-8 mo: 24% of Bangladeshi and 16% of Peruvian children. With the exception of Bangladesh, the prevalence of inadequate available protein intake decreased by age 9-12 mo and was very low in all sites (0-2%) after 12 mo of age. Inadequate protein intake in children <12 mo of age was due primarily to low energy intake from complementary foods, not inadequate protein density.Conclusions: Overall, most children consumed protein amounts greater than requirements, except for the younger breastfeeding children, who were consuming low amounts of complementary foods. These findings reinforce previous evidence that dietary protein is not generally limiting for children in LICs compared with estimated requirements for healthy children, even after accounting for protein quality. However, unmeasured effects of infection and intestinal dysfunction on the children's protein requirements could modify this conclusion.

Acute and Long-Term Impact of High-Protein Diets on Endocrine and Metabolic Function, Body Composition, and Exercise-Induced Adaptations

BACKGROUND

High-protein diets have been shown to improve body composition through alterations in satiety, muscle protein synthesis, and the thermic effect of food.

AIM

Given these findings, the purpose of this review is to discuss the integration of the specific hormonal and metabolic effects of high-protein diets following both acute and long-term usage, especially with regard to body composition.

METHODS

Full-text articles were obtained through PubMed by using the terms "high-protein diet and body composition," "high-protein diet and exercise," "high-protein diet risk," "high-protein diet side effects," "protein quality PDCAAS," "RDA for protein," and "daily protein recommendation." Articles were initially screened according to their title and abstract; careful evaluation of the full manuscripts was then used to identify relevant articles.

RESULTS

The higher satiety exerted by high-protein diets is generated through increments in anorexigenic, as well as decrements in orexigenic hormones. Improvements in muscle mass are achieved by activation of muscle protein synthesis acting through the mTOR pathway. High thermic effect of food is caused due to necessary deamination, gluconeogenesis, and urea synthesis caused by high-protein diets. Interestingly, high-protein diets in both hypo- and normocaloric conditions have shown to improve body composition, whereas in combination with hypercaloric conditions does not seem to increase fat mass, when the excess energy comes from protein.

CONCLUSIONS

High protein diets effectively improve body composition by acting through different pathways.

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.

Protein digestibility-corrected amino acid scores and digestible indispensable amino acid scores differentially describe protein quality in growing male rats

BACKGROUND

The FAO has recommended replacing the protein digestibility-corrected amino acid score (PDCAAS) with the digestible indispensable amino acid score (DIAAS).

OBJECTIVE

The objective of this study was to compare aspects underlying the calculation of the DIAAS and PDCAAS, including 1) fecal digestibility vs. ileal digestibility, 2) using a single nitrogen digestibility value for all amino acids, and 3) the effect of truncation. Truncated PDCAAS and untruncated DIAAS values calculated as formally defined were also compared and DIAAS data presented for 14 dietary protein sources.

METHODS

Semisynthetic wheat starch-based diets were formulated to contain the test protein (as consumed by humans) source (whey- and soy-protein isolates, milk-, whey-, rice- and pea- protein concentrates, cooked kidney beans, roasted peanuts, cooked peas, corn-based breakfast cereal, cooked rice, cooked rolled oats, and wheat bran) as the sole nitrogen source and with an indigestible marker (titanium dioxide). Growing male rats (∼250 g bodyweight) were given a basal casein-based diet from day 1 to day 7 and then allocated (n = 6) to the test diets for day 8 to day 14 before ileal digesta were collected after the rats were killed. Total feces were collected from day 11 to day 14.

RESULTS

True fecal nitrogen digestibility was different (P < 0.05; 10% difference on average) from true ileal nitrogen digestibility for 11 of the 14 protein sources. True ileal nitrogen digestibility was different (P < 0.05) from true ileal amino acid digestibility for almost half of the indispensable and conditionally indispensable amino acids (differences ranged from 0.9% to 400%). DIAAS values ranged from 0.01 for a corn-based cereal to 1.18 for milk protein concentrate.

CONCLUSION

Untruncated PDCAAS values were generally higher than a DIAAS values, especially for the poorer quality proteins; therefore, the reported differences in the scores are of potential practical importance for populations in which dietary protein intake may be marginal.

Nutrient composition and protein quality evaluation of eri silkworm (Samia ricinii) prepupae and pupae

Eri silkworm (Samia ricinii) is a traditional source of food in northeast India, where it is grown primarily for silk and food uses. Nutrient analysis showed that the proximate composition of eri silkworm prepupae and pupae grown on either castor or tapioca were comparable and it was a good source of protein (16g%), fat (8g%) and minerals. The amino acid scores of eri prepupae and pupae protein were 99 and 100, respectively, with leucine as the limiting amino acid in both cases. Net protein utilisation (NPU) of prepupae and pupae was 41 as compared to 62 in casein. Protein digestibility corrected amino acid score (PDCAAS) was 86. The high protein content in the defatted eri silkworm meal (75%) with 44% total essential amino acids makes it an ideal candidate for preparing protein concentrate isolates with enhanced protein quality that can be used in animal nutrition.