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The effects of β-lactoglobulin (β-LG), β-casein (β-CN), and κ-CN variants and β-κ-CN haplotypes on the relative concentrations of the major milk proteins α-lactalbumin (α-LA), β-LG, αS1-CN, αS2-CN, β-CN, and κ-CN and milk production traits were estimated in the milk of 1,912 Dutch Holstein-Friesian cows. We show that in the Dutch Holstein-Friesian population, the allele frequencies have changed in the past 16 years. In addition, genetic variants and casein haplotypes have a major impact on the protein composition of milk and explain a considerable part of the genetic variation in milk protein composition. The β-LG genotype was associated with the relative concentrations of β-LG (A » B) and of α-LA, αS1-CN, αS2-CN, β-CN, and κ-CN (B>A) but not with any milk production trait. The β-CN genotype was associated with the relative concentrations of β-CN and αS2-CN (A2>A1) and of αS1-CN and κ-CN (A1>A2) and with protein yield (A2>A1). The κ-CN genotype was associated with the relative concentrations of κ-CN (B>E>A), αS2-CN (B>A), α-LA, and αS1-CN (A>B) and with protein percentage (B>A). Comparing the effects of casein haplotypes with the effects of single casein variants can provide better insight into what really underlies the effect of a variant on protein composition. We conclude that selection for both the β-LG genotype B and the β-κ-CN haplotype A2B will result in cows that produce milk that is more suitable for cheese production.

Some wheat cultivars show a linear relationship between grain protein concentration (GPC) and baking volume, but others display a saturation curve. Such a saturation curve could be general, but in some cultivars it might only appear at GPC > 17%. However, such GPC is mostly not achieved in the field. Pot experiments with high nitrogen application reliably result in GPC > 17%. In a pot experiment with a high (N1) and an excessive N level (N2) and four cultivars (Akteur, Arnold, Discus and Hystar), the change in grain protein composition and the relationship between different protein fractions and baking volume at GPC > 17% was investigated. GPC ranged from 17 to 24% and mean nitrogen content per grain from 1.2 to 1.8 mg. The N2 treatment increased GPC and mean nitrogen content per grain in the Akteur and Discus cultivar, but not in Arnold and Hystar. N2 increased concentration of gliadin by 10 to 34% and glutenin macropolymer (GMP) in all cultivars by 12 to 73%. Glutenin concentration was increased by N2 in Akteur and Discus (19 to 36%), but was decreased by N2 in the Arnold and Hystar cultivar. Baking volume was moderately increased by N2 in all cultivars by 6 to 9% and correlated significantly with most glutenin fractions in the Akteur and Discus cultivar, with GMP in Arnold and with HMW-GS to LMW-GS ratio in Hystar. Thus, specific effects on grain protein by N2 were responsible for the increased baking volume in each cultivar. However, as gliadin and its sub-fractions hardly correlated with baking volume, a positive effect of increasing gliadin proteins on baking quality was not obvious.

Nitrogen (N) is a key nutrient influencing wheat growth, grain yield, and quality. A long-term field experiment was conducted using cultivar Zhengmai 1860 to clarify the effects of N topdressing on grain protein composition, starch accumulation, and yield. Treatments included a basal N application of 150 kg ha (N1) combined with four topdressing rates at jointing: 37.5, 75, 112.5, and 150 kg ha (N1 + 37.5, N1 + 75, N1 + 112.5, N1 + 150). Nitrogen topdressing significantly affected the physiological and biochemical characteristics of grains at different spike positions. Amylopectin, globulin, soluble starch (SS), and soluble starch synthase (SSS) accumulated most under 75-112.5 kg ha , with N1 + 75 showing the strongest response in basal and middle spike grains. Amylose and granule-bound starch synthase (GBSS) peaked at the middle spike under N1 + 112.5. Protein component (gliadin, glutelin, albumin), amino acids, glutamate synthase (GOGAT), and glutamine synthetase (GS) increased progressively with higher N rates, with maximum accumulation at N1 + 150. Nitrogen topdressing also enhanced spike number (5.05-37.13%), grains per spike (3.86-16.22%), and 1000-grain weight (2.72-5.79%), with the highest yield (9451.7 kg ha ) at N1 + 112.5. These results highlight the critical role of optimized N management in improving grain composition and yield in wheat.

The postprandial rise in essential amino acid (EAA) concentrations modulates the increase in muscle protein synthesis rates after protein ingestion. The EAA content and AA composition of the dietary protein source contribute to the differential muscle protein synthetic response to the ingestion of different proteins. Lower EAA contents and specific lack of sufficient leucine, lysine, and/or methionine may be responsible for the lower anabolic capacity of plant-based compared with animal-based proteins. We compared EAA contents and AA composition of a large selection of plant-based protein sources with animal-based proteins and human skeletal muscle protein. AA composition of oat, lupin, wheat, hemp, microalgae, soy, brown rice, pea, corn, potato, milk, whey, caseinate, casein, egg, and human skeletal muscle protein were assessed using UPLC–MS/MS. EAA contents of plant-based protein isolates such as oat (21%), lupin (21%), and wheat (22%) were lower than animal-based proteins (whey 43%, milk 39%, casein 34%, and egg 32%) and muscle protein (38%). AA profiles largely differed among plant-based proteins with leucine contents ranging from 5.1% for hemp to 13.5% for corn protein, compared to 9.0% for milk, 7.0% for egg, and 7.6% for muscle protein. Methionine and lysine were typically lower in plant-based proteins (1.0 ± 0.3 and 3.6 ± 0.6%) compared with animal-based proteins (2.5 ± 0.1 and 7.0 ± 0.6%) and muscle protein (2.0 and 7.8%, respectively). In conclusion, there are large differences in EAA contents and AA composition between various plant-based protein isolates. Combinations of various plant-based protein isolates or blends of animal and plant-based proteins can provide protein characteristics that closely reflect the typical characteristics of animal-based proteins.

Plant-based meat analogues (PBMs) are increasingly interesting to customers because of their meat-like quality and contribution to a healthy diet. The single-screw extruder is an important method for processing PBMs, and the characteristics of the product are directly affected by the composition of the raw materials; however, little research focuses on this issue. To explore the effect of protein composition on the quality characteristics of PBMs produced by a single-screw extruder, four soybean varieties used in China (Heihe 43 (HH 43), Jiyu 86 (JY 86), Suinong 52 (SN 52), and Shengfeng 5 (SF 5)) were selected. The 11S/7S ratios for these varieties ranged from 1.0: 1 to 2.5: 1 in order to produce PBMs with different protein compositions. The structure, processing, nutrition, and flavor characteristics were explored to analyze their differences. The results showed that protein composition affected the structure of PBMs, but the correlation was not significant. Meanwhile, a lower 11S/7S ratio (HH 43) did not prove to be a favorable characteristic for the processing of PBMs. From the perspective of nutrition and flavor, it seems acceptable to use a moderate 11S/7S ratio (JY 86 and SN 43) to produce PBMs. This study proved that the protein composition of raw materials affects the characteristics of PBM products produced by a single-screw extruder. To produce PBMs of higher quality, soybeans with a markedly different 11S/7S ratio should not be selected.

There is a global trend of an increased interest in plant-based diets. This includes an increase in the consumption of plant-based proteins at the expense of animal-based proteins. Plant-derived proteins are now also frequently applied in sports nutrition. So far, we have learned that the ingestion of plant-derived proteins, such as soy and wheat protein, result in lower post-prandial muscle protein synthesis responses when compared with the ingestion of an equivalent amount of animal-based protein. The lesser anabolic properties of plant-based versus animal-derived proteins may be attributed to differences in their protein digestion and amino acid absorption kinetics, as well as to differences in amino acid composition between these protein sources. Most plant-based proteins have a low essential amino acid content and are often deficient in one or more specific amino acids, such as lysine and methionine. However, there are large differences in amino acid composition between various plant-derived proteins or plant-based protein sources. So far, only a few studies have directly compared the muscle protein synthetic response following the ingestion of a plant-derived protein versus a high(er) quality animal-derived protein. The proposed lower anabolic properties of plant- versus animal-derived proteins may be compensated for by (i) consuming a greater amount of the plant-derived protein or plant-based protein source to compensate for the lesser quality; (ii) using specific blends of plant-based proteins to create a more balanced amino acid profile; (iii) fortifying the plant-based protein (source) with the specific free amino acid(s) that is (are) deficient. Clinical studies are warranted to assess the anabolic properties of the various plant-derived proteins and their protein sources in vivo in humans and to identify the factors that may or may not compromise the capacity to stimulate post-prandial muscle protein synthesis rates. Such work is needed to determine whether the transition towards a more plant-based diet is accompanied by a transition towards greater dietary protein intake requirements.

Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington’s disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity. The mechanisms underlying Huntingtin protein (Htt) aggregation are not fully understood. Here the authors perform a detailed investigation of the ultrastructural and biochemical properties of huntingtin cytoplasmic and nuclear inclusions, and reveal that they form via distinct mechanisms and exert their toxicity via different pathways.

How soft corona, the protein corona’s outer layer, contributes to biological identity of nanomaterials is largely because capturing protein composition of the soft corona in situ remains challenging. We herein develop an in situ Fishing method that can monitor the dynamic formation of protein corona on ultra-small chiral Cu 2 S nanoparticles (NPs) allowing us to directly separate and identify the corona protein composition. Our method detects spatiotemporal processes in the evolution of hard and soft coronas on chiral NPs, revealing subtle differences in NP − protein interactions even within several minutes. This study highlights the importance of in situ and dynamic analysis of soft/hard corona, provides insights into the role of soft corona in mediating biological responses of NPs, and offers a universal strategy to characterize soft corona to guide the rational design of biomedical nanomaterials. Characterizing the soft protein corona on nanoparticles i.e. the outer layer of the corona, remains a longstanding challenge. Here, the authors develop an in situ method to monitor the dynamic processes of multilayered corona formation and evolution that offers a universal strategy to characterize the soft corona proteome.

Protein corona formation is critical for the design of ideal and safe nanoparticles (NPs) for nanomedicine, biosensing, organ targeting, and other applications, but methods to quantitatively predict the formation of the protein corona, especially for functional compositions, remain unavailable. The traditional linear regression model performs poorly for the protein corona, as measured by R² (less than 0.40). Here, the performance with R² over 0.75 in the prediction of the protein corona was achieved by integrating a machine learning model and meta-analysis. NPs without modification and surface modification were identified as the two most important factors determining protein corona formation. According to experimental verification, the functional protein compositions (e.g., immune proteins, complement proteins, and apolipoproteins) in complex coronas were precisely predicted with good R² (most over 0.80). Moreover, the method successfully predicted the cellular recognition (e.g., cellular uptake by macrophages and cytokine release) mediated by functional corona proteins. This workflow provides a method to accurately and quantitatively predict the functional composition of the protein corona that determines cellular recognition and nanotoxicity to guide the synthesis and applications of a wide range of NPs by overcoming limitations and uncertainty.

In recent years, the awareness and willingness of consumers to consume healthy food has grown significantly. In order to meet these needs, scientists are looking for innovative methods of food production, which is a source of easily digestible protein with a balanced amino acid composition. Yeast protein biomass (single cell protein, SCP) is a bioavailable product which is obtained when primarily using as a culture medium inexpensive various waste substrates including agricultural and industrial wastes. With the growing population, yeast protein seems to be an attractive alternative to traditional protein sources such as plants and meat. Moreover, yeast protein biomass also contains trace minerals and vitamins including B-group. Thus, using yeast in the production of protein provides both valuable nutrients and enhances purification of wastes. In conclusion, nutritional yeast protein biomass may be the best option for human and animal nutrition with a low environmental footprint. The rapidly evolving SCP production technology and discoveries from the world of biotechnology can make a huge difference in the future for the key improvement of hunger problems and the possibility of improving world food security. On the market of growing demand for cheap and environmentally clean SCP protein with practically unlimited scale of production, it may soon become one of the ingredients of our food. The review article presents the possibilities of protein production by yeast groups with the use of various substrates as well as the safety of yeast protein used as food.