Characterisation, physicochemical and functional properties of protein isolates from Amygdalus pedunculata Pall seeds

Physicochemical and functional properties of two kinds of Schisandra proteins and their antioxidant activity in H2O2-treated HepG2 cells

Schisandra chinensis protein (SCP) and Schisandra sphenantherae protein (SSP) were extracted by alkali extraction and isoelectric precipitation, and the amino acid compositions, structures, and physicochemical properties of the two proteins were analyzed to evaluate their functional properties. The effects of SCP and SSP on proliferation, protection, and anti-apoptosis of H2O2-treated HepG2 cells after oxidative stress were investigated. The results showed that SCP had a higher content of essential amino acids (16.27 ± 0.76) than SSP. Scanning electron microscopy and Fourier-transform infrared spectroscopy analyses, as well as substituent distribution in electrophoresis, revealed the structural differences between the two proteins; in particular, the disulfide bond content is higher in SCP, which was also found to be more stable in terms of heat tolerance (114.7 °C), solubility (47.18 %), emulsification (158.57 m2/g), emulsion stability (89.53 %), foaming (226 %), and foaming stability (90.32 %). In an in vitro experiment, SSP was more effective in protecting HepG2 cells from H2O2-treated oxidative damage, effectively inhibiting the levels of reactive oxygen species and malondialdehyde, maintaining the stability of cell membranes, promoting antioxidant mechanisms, and decreasing apoptosis by regulating the expression of genes and proteins related to the mitochondrial apoptotic pathway. These results suggest that both SCP and SSP are suitable as novel food additives, and that the excellent functional properties and thermal stability of SCP make it a potential nutritional resource in the food industry. In addition, SSP has potential as a protein resource with antioxidant activity.

Effect of ultrasonic-assisted enzymatic extraction on proso millet bran protein: extraction rate, structural and functional properties

BACKGROUND

Proso millet bran protein (PMBP), derived from agricultural by-products, possesses high nutritional value, despite its challenging extraction process. The present study proposes an extraction method for PMBP using ultrasound-assisted cellulase technology (UAE), and optimizes the process parameters. Non-waxy (N-PMBP) and waxy (W-PMBP) PMBPs, extracted through alkaline solubilization and acid precipitation (conventional treatment, CT), served as control groups to assess the impact of UAE on the structure and functionality of PMBP, as well as the distinctions between N-PMBPs and W-PMBPs.

RESULTS

At an ultrasonic power of 420 W, cellulase concentration of 80 U g-1, enzymolysis pH of 5.0, enzymolysis temperature of 55 °C and enzymolysis time of 3 h, the maximum PMBP extraction rate was achieved at 76.80%. Compared to CT, UAE extraction resulted in enhancements in α-helix and random content, particle size, surface hydrophobicity (H0) and ξ-potential value, leading to improved functionality of the PMBPs. Additionally, significant functional and structural disparities were observed between N-PMBPs and W-PMBPs. Although no significant difference in molecular weight was detected, each exhibited three major bands. W-PMBPs exhibited significantly higher beta-sheet content compared to N-PMBPs, whereas the reverse trend was observed for α-helix content. W-PMBPs displayed strong solubility and water/oil holding capacity compared to N-PMBPs, albeit with lower emulsifying properties and H0.

CONCLUSION

UAE could enhance PMBP extraction, inducing structural and functional changes in PMBPs compared to CT. Significant differences in functionality and structure were observed between N-PMBPs and W-PMBPs, providing fundamental data and a theoretical basis for PMBP development and utilization. © 2025 Society of Chemical Industry.

Effects of various sterilization treatments on the structural and functional alterations of the epigallocatechin-3-gallate-casein complex

The effects of dairy sterilization techniques (65 °C/30 min, 72 °C/15 s, 85 °C/15 s, 100 °C/5 min, and 121 °C/5 s) on the epigallocatechin-3-gallate-casein (EGCG-CS) complexes were investigated through the structural and functional characteristics in this work. Fourier transform infrared spectroscopy (FT-IR) detection showed the redshirting of the absorption peak suggested structural changes in the amide I area. Field emission scanning electron microscopy (FESEM) and viscosity measurements proved that treatments above 85 °C broke non-covalent bonds, leading to instability and low viscosity of EGCG-CS. Moreover, the values of surface hydrophobicity, solubility, and sulfhydryl group content appeared the same phenomenon of first rising then falling at higher temperatures, resulting from the CS protein exhibited obvious peptide chain stretch and hydrophobic residue exposure. Notably, the 15-s thermal treatment at 85 °C enhanced the structural stability, foaming, and emulsifying abilities of the EGCG-CS complexes, providing important technology information for industrial applications.

Structural and functional properties of proteins isolated from four species of microalgae and their application in air-water interface stabilization

Herein, we extracted proteins from four microalgae: Chlamydomonas reinhardtii (CHR), Euglena gracilis (EUG), Spirulina platensis (SPP), and Spirulina maxima (SPM). Subsequently, their physicochemical and functional properties, as well as air-water interface adsorption behavior were investigated. Results demonstrated that the solubility and emulsifying properties of these proteins were significantly affected by pH, with minimum values observed near their isoelectric point (3.5) and maximum values at pH 11.0. Interestingly, the emulsifying properties of the four proteins were superior to soy protein isolate in the pH range of 3.0-7.0, indicating that these microalgae proteins may be suitable for applying as emulsifiers in foods. EUG exhibited the highest water/oil binding capacity, emulsifying activity, and emulsifying stability, which were attributed to its high surface hydrophobicity and β-sheet content, as well as small particle size. Dynamic adsorption behavior analysis illustrated that EUG showed faster diffusion and rearrangement rates, as well as a higher final equilibrated surface pressure value, contributing to its highest foaming capacity and foaming stability. This study greatly enhances the understanding of microalgae proteins and is expected to establish a theoretical foundation for developing novel protein resources that can be utilized in the foamed and emulsion-based food fabrication, including whipped cream and functional beverages.

Perilla Seed Oil and Protein: Composition, Health Benefits, and Potential Applications in Functional Foods

Perilla (Perilla frutescens) seeds are emerging as a valuable resource for functional foods and medicines owing to their rich oil and protein content with diverse nutritional and health benefits. Perilla seed oil (PSO) possesses a high level of a-linolenic acid (ALA), a favorable ratio of unsaturated to saturated fatty acids, and other active ingredients such as tocopherols and phytosterols, which contribute to its antioxidant, anti-inflammatory, and cardiovascular protective effects. The balanced amino acid ratio and good functional properties of perilla seed protein make it suitable for a variety of food applications. The chemical composition, health benefits, and potential applications of PSO as well as the structural characterization, functional properties, modification methods, bioactivities, and application scenarios of perilla seed protein are comprehensively presented in this paper. Furthermore, the challenges as well as future prospects and research focus of PSO and perilla seed protein are discussed. The growing interest in plant-based diets and functional foods has made PSO and perilla seed protein promising ingredients for the development of novel foods and health products. The purpose of this paper is to highlight implications for future research and development utilizing these two untapped resources to improve human health and nutrition.

Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts as an emerging source of protein: extraction, physicochemical and functional properties

BACKGROUND

The increasing demand for sustainable alternatives to traditional protein sources, driven by population growth, underscores the importance of protein in a healthy diet. Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts are currently underutilized as plant-based proteins but hold great potential in the food industry. However, there is insufficient information available on pecan protein, particularly its protein fractions. This study aimed to explore the physicochemical and functional properties of protein isolate and the main protein fraction glutelin extracted from pecan nuts.

RESULTS

The results revealed that glutelin (820.67 ± 69.42 g kg-1) had a higher crude protein content compared to the protein isolate (618.43 ± 27.35 g kg-1), while both proteins exhibited amino acid profiles sufficient for adult requirements. The isoelectric points of protein isolate and glutelin were determined to be pH 4.0 and pH 5.0, respectively. The denaturation temperature of the protein isolate (90.23 °C) was higher than that of glutelin (87.43 °C), indicating a more organized and stable conformation. This is further supported by the fact that the protein isolate had a more stable main secondary structure than glutelin. Both proteins demonstrated improved solubility, emulsifying, and foaming properties at pH levels deviating from their isoelectric points in U-shaped curves. Compared to the protein isolate, glutelin displayed superior water and oil absorption capacity along with enhanced gelling ability.

CONCLUSION

The protein isolate and glutelin from pecan nuts exhibited improved stability and competitive functional properties, respectively. The appropriate utilization of these two proteins will support their potential as natural ingredients in various food systems. © 2024 Society of Chemical Industry.

Structural changes and functional characteristics of common vetch isolate proteins altered by different pH-shifting treatments

To investigate protein structure and functional changes, common vetch protein isolate (CVPI) during pH-shifting were performed. Results showed secondary and tertiary structures of CVPI were improved during these treatments compared with the pH 7.0. Scanning electron microscopy showed the microstructure was changed from lamellar to spherical granular and rod-like structure during pH - shifting. Under 8 pH treatments (pH 2.0, 3.0, 12.0, 2.0 → 7.0, 3.0 → 7.0, 12.0 → 7.0, 11.0 → 9.0 and 11.0 → 7.0), the average particle sizes were smaller and from 82 to 146 nm. Under 8 pH treatments (pH 2.0, 3.0, 11.0, 12.0, 11.0 → 9.0, 11.0 → 7.0,12.0 → 9.0 and 12.0 → 7.0), the protein solubility was higher and from 63 to 86 %. Under 3 pH treatments (pH 2.0, 11.0 and 12.0), the emulsion activity index and emulsion stability index was higher and from 40 to 60 m2/g and from 54 to 97 min. Under 5 pH treatments (pH 2.0, 12.0, 11.0 → 9.0, 12.0 → 9.0 and 12.0 → 7.0), the foaming capacity and foaming stability was higher and from 145 to 185 % and from 67 to 82 %. Therefore, the pH - shifting treatment gave the CVPI improved characteristics in structural and functional properties.

Structure, Functional Properties, and Applications of Foxtail Millet Prolamin: A Review

Foxtail millet prolamin, one of the major protein constituents of foxtail millet, has garnered attention due to its unique amino acid composition and function. Foxtail millet prolamin exhibits specific physicochemical and functional characteristics, such as solubility, surface hydrophobicity, emulsifying, and foaming properties. These characteristics have been exploited in the preparation and development of products, including plant-based alternative products, nutritional supplements, and gluten-free foods. Additionally, because of the favorable biocompatibility and biodegradability, foxtail millet prolamin is frequently used as a carrier for encapsulation and targeted delivery of bioactive substances. Moreover, studies have shown that foxtail millet prolamin is highly nutritious and displays various biological activities like antioxidant effects, anti-inflammatory properties, and anti-diabetic potential, making it a valuable ingredient in medicinal products and contributing to its potential role in therapeutic diets. This review summarizes the current knowledge of the amino acid composition and structural characteristics of foxtail millet prolamin, as well as the functional properties, biological activities, and applications in functional food formulation and drug delivery strategy. Challenges and future perspectives for the utilization of foxtail millet prolamin are also pointed out. This review aims to provide novel ideas and broad prospects for the effective use of foxtail millet prolamin.

Chloroplast genome data of five Amygdalus species: Clarifying genome structure and phylogenetic relationships

Amygdalus species have considerable ecological and economic value, however, the phylogenetic relationships among Amygdalus remain controversy. In this study, we sequenced and assembled the chloroplast (cp) genomes of five Amygdalus species: Prunus communis, P. mongolica, P. pedunculata, P. triloba, and P. mira. We then conducted comparative genomic analyses and constructed their phylogenetic relationships. The genome length ranged from 157,870 to 158,451 bp, and 131 genes were annotated (86 protein-coding genes, 37 tRNAs, and 8 rRNAs). Additionally, 49-57 simple sequence repeats were detected, with most in the large single-copy region and with AT base preferences. Comparative genomic analyses revealed high similarities in structure, order, and gene content. However, we identified four highly divergent sequences: trnR-UCU-atpA, nbdhC-trnV-UAC, ycf4-cemA, and rpl32-trnL-UAG. The phylogenomic relationship analysis suggested that the Amygdalus species were grouped together, in which P. pedunculata, P. triloba, and Prunus tangutica were categorized into a branch, P. mongolica and Prunus davidiana were clustered a branch. This study provides an improved understanding of the genetic relationships among the Amygdalus and provides a basis for the development and utilization of Amygdalus resources.

Complete mitochondrial genome of the endangered Prunus pedunculata (Prunoideae, Rosaceae) in China: characterization and phylogenetic analysis

Introduction

Prunus pedunculata (Prunoideae: Rosaceae), a relic shrub with strong resistance and multiple application values, is endangered in China. Extensive research had been devoted to gene expression, molecular markers, plastid genome analysis, and genetic background investigations of P. pedunculata. However, the mitochondrial genome of this species has not been systematically described, owing to the complexity of the plant mitogenome.

Methods

In the present research, the complete mitochondrial genome of P. pedunculata was assembled, annotated, and characterized. The genomic features, gene content and repetitive sequences were analyzed. The genomic variation and phylogenetic analysis have been extensively enumerated.

Results and discussion

The P. pedunculata mitogenome is a circular molecule with a total length of 405,855 bp and a GC content of 45.63%, which are the smallest size and highest GC content among the known Prunus mitochondrial genomes. The mitogenome of P. pedunculata encodes 62 genes, including 34 unique protein-coding genes (PCGs, excluding three possible pseudogenes), three ribosomal RNA genes, and 19 transfer RNA genes. The mitogenome is rich in repetitive sequences, counting 112 simple sequence repeats, 15 tandem repeats, and 50 interspersed repetitive sequences, with a total repeat length of 11,793 bp, accounting for 2.91% of the complete genome. Leucine (Leu) was a predominant amino acid in PCGs, with a frequency of 10.67%, whereas cysteine (Cys) and tryptophan (Trp) were the least adopted. The most frequently used codon was UUU (Phe), with a relative synonymous codon usage (RSCU) value of 1.12. Selective pressure was calculated based on 20 shared PCGs in the mitogenomes of the 32 species, most of which were subjected to purifying selection (Ka/Ks < 1), whereas ccmC and ccmFn underwent positive selection. A total of 262 potential RNA editing sites in 26 PCGs were identified. Furthermore, 56 chloroplast-derived fragments were ascertained in the mitogenome, ranging from 30 to 858 bp, and were mainly located across IGS (intergenic spacer) regions or rRNA genes. These findings verify the occurrence of intracellular gene transfer events from the chloroplast to the mitochondria. Furthermore, the phylogenetic relationship of P. pedunculata was supported by the mitogenome data of 30 other taxa of the Rosaceae family. Understanding the mitochondrial genome characteristics of P. pedunculata is of great importance to promote comprehension of its genetic background and this study provides a basis for the genetic breeding of Prunus.

Plant-based proteins: advanced extraction technologies, interactions, physicochemical and functional properties, food and related applications, and health benefits

Even though plant proteins are more plentiful and affordable than animal proteins in comparison, direct usage of plant-based proteins (PBPs) is still limited because PBPs are fed to animals as feed to produce animal-based proteins. Thus, this work has comprehensively reviewed the effects of various factors such as pH, temperature, pressure, and ionic strength on PBP properties, as well as describes the protein interactions, and extraction methods to know the optimal conditions for preparing PBP-based products with high functional properties and health benefits. According to the cited studies in the current work, the environmental factors, particularly pH and ionic strength significantly affected on physicochemical and functional properties of PBPs, especially solubility was 76.0% to 83.9% at pH = 2, while at pH = 5.0 reduced from 5.3% to 9.6%, emulsifying ability was the lowest at pH = 5.8 and the highest at pH 8.0, and foaming capacity was lowest at pH 5.0 and the highest at pH = 7.0. Electrostatic interactions are the main way for protein interactions, which can be used to create protein/polysaccharide complexes for food industrial purposes. The extraction yield of proteins can be reached up to 86-95% with high functional properties using sustainable and efficient routes, including enzymatic, ultrasound-, microwave-, pulsed electric field-, and high-pressure-assisted extraction. Nondairy alternative products, especially yogurt, 3D food printing and meat analogs, synthesis of nanoparticles, and bioplastics and packaging films are the best available PBPs-based products. Moreover, PBPs particularly those that contain pigments and their products showed good bioactivities, especially antioxidants, antidiabetic, and antimicrobial.

Proteins from Blackberry Seeds: Extraction, Osborne Isolate, Characteristics, Functional Properties, and Bioactivities

Blackberry fruit contains high levels of nutrients and phenolic compounds. Blackberry pomace accounts for 20~30% of its whole fruit during processing and is generally treated as fertilizer. Blackberry pomace has many seeds that contain carbohydrates, polyphenols, flavonoids, pectin, protein, and other bioactive nutrients. However, its functional properties and seed protein compositions have not been reported. We used a single-factor experiment, response surface, and Osborne isolate method to extract protein isolate, albumin, globulin, glutelin, and prolamin from blackberry seeds for the first time and evaluated their characteristics and functional properties. Glutelin and protein isolate showed good water-holding capacity, emulsification, and foaming capacity, while albumin and globulin showed good oil-holding capacity and thermal stability. They were found to have good antioxidant activities that might be good DPPH free radical scavengers, especially prolamin, which has the lowest IC50 value (15.76 μg/mL). Moreover, globulin had the lowest IC50 value of 5.03 μg/mL against Hela cells, 31.82 μg/mL against HepG2 cells, and 77.81 μg/mL against MCF-7 cells and a high selectivity index (SI), which suggested globulin had better anti-cervical, antihepatoma, and anti-breast activity but relatively low cytotoxicity. These seed proteins may have great prospects for the development and application of food and drugs in the future.

Almond (Amygdalus communis L.) kernel protein: A review on the extraction, functional properties and nutritional value

Almond (Amygdalus communis L.) kernel, a source of nutrients in many traditional diets, is being used more frequently as a nutritious snack and component. It is well known that almond kernels are a protein-rich food. Compared to the amino acid profile recommended by FAO, almond kernel protein is an ideal protein with perfect balance of amino acids. It also has a variety of better functional properties such as solubility, emulsifying ability, oil absorption capacity and foaming ability. pH and ion strength have significant influences on these functional properties. Furthermore, almond kernel protein is easily digested and absorbed by the human body. So almond kernel protein can be used as a high-quality protein resource. This review describes the techniques for extracting almond kernel protein, as well as its functional properties, nutritional worth, and applications. The purpose of this review is to provide ideas for the effective use of almond kernel protein and the creation of related products.

Comparative assessment of nutritional and functional properties of different sorghum genotypes for ensuring nutritional security in dryland agro-ecosystem

The cultivation of unique sorghum (resistant to abiotic stresses and re-recognized as healthy food) has attracted interest as an environmentally friendly minor cereal and may be a solution to food and nutritional security. However, information about how the use of selected sorghum grains affects nutritive values and its functional properties from sorghum flours is still lacking. To address this question, we selected six sorghum varieties (i.e., JinZa 34, LiaoZa 19, JinNuo 3, JiZa 127, JiNiang 2, and JiaXian) for the comprehensive analysis of the relationship among nutritional compositions, energy value contributions, and functional properties of sorghum grains. Results showed that Carr's index (CI) and angle of repose (AR) of all sorghum flours indicated good flow and compressibility properties in terms of micrometric parameters. All sorghums were considered free of tannin. Based on the scatterplot analysis, the proportions of energy contributions due to protein, fat, and carbohydrate (CHO), were highly positively correlated with protein, fat, and CHO, respectively. The significantly different flours of six sorghum varieties resulted in different functional properties. The amylose content showed a highly negative association with light transmittance and water and oil absorption capacities. In addition, amylose had a highly positive relationship with water solubility (WS) and swelling power (SP). JinNuo 3 had the highest nutritional compositions [proximate, mineral, anti-nutritional values, and amino acid (AA) profiles] and functional properties indicating that it could be used as a brewing liquor. Our findings will provide a new opportunity to cultivate sorghum as an environment friendly minor cereal crop in dryland agro-ecosystems of arid and semi-arid regions of northern China for nutritional security, agriculture processing, and non-food industry in the future.

Structural Modification of Jackfruit Leaf Protein Concentrate by Enzymatic Hydrolysis and Their Effect on the Emulsifier Properties

Jackfruit leaf protein concentrate (LPC) was hydrolyzed by pepsin (H–Pep) and pancreatin (H–Pan) at different hydrolysis times (30–240 min). The effect of the enzyme type and hydrolysis time of the LPC on the amino acid composition, structure, and thermal properties and its relationship with the formation of O/W emulsions were investigated. The highest release of amino acids (AA) occurred at 240 min for both enzymes. H–Pan showed the greatest content of essential and hydrophobic amino acids. Low β-sheet fractions and high β-turn contents had a greater influence on the emulsifier properties. In H–Pep, the β-sheet fraction increased, while in H–Pan it decreased as a function of hydrolysis time. The temperatures of glass transition and decomposition were highest in H–Pep due to the high content of β-sheets. The stabilized emulsions with H–Pan (180 min of hydrolysis) showed homogeneous distributions and smaller particle sizes. The changes in the secondary structure and AA composition of the protein hydrolysates by the effect of enzyme type and hydrolysis time influenced the emulsifying properties. However, further research is needed to explore the use of H–Pan as an alternative to conventional emulsifiers or ingredients in functional foods.

Physico-chemical properties, antioxidant activity, and ACE inhibitory activity of protein hydrolysates from wild jujube seed

Wild jujube seed protein (WJSP) as one kind of functional food material has attracted much attention due to its highly nutritive and medicinal value in anti-inflammatory and improving immunomodulatory ability. However, owing to its large molecular weight and complex structure, biological activities of WJSP were greatly limited and cannot be fully utilized by the human body. Therefore, how to improve the bioavailability of WJSP and develop promising WJSP nutritious materials is a great challenge. In this work, wild jujube seed protein hydrolysates (WJSPHs) were prepared from WJSP via enzymatic hydrolysis method, and their physico-chemical properties, antioxidant activity, and angiotensin converting enzyme (ACE) inhibitory activity in vitro have been investigated for the first time. SDS-PAGE electrophoresis and size-exclusion chromatographic results indicate that WJSPHs have lower molecular weight distribution (< 5,000 Da) than WJSP. Circular dichroism (CD) spectroscopy and Fourier transform infrared spectroscopy (FTIR) results illustrated that random coil is the main secondary structure of WJSPHs. Antioxidant experiments indicate that WJSPHs exhibit high radicals-scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (94.60%), 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS⁺ ) radicals (90.84%), superoxide radicals (44.77%), and hydroxyl radicals (47.77%). In vitro, WJSPHs can significantly decrease the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), and increase the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in HepG2 cells. Moreover, ACE activity was found that can be significantly inhibited by WJSPHs (73.02%). Therefore, all previously mentioned results suggest that WJSPHs may be a promising antioxidant food to prevent oxidative-related diseases in future. PRACTICAL APPLICATION: This study shows that WJSPHs exhibit high antioxidant activity and ACE inhibitory activity in vitro, which provide potential application value as antioxidant peptides to prevent oxidative-related diseases.

Influence of high-intensity ultrasound on physicochemical and functional properties of a guamuchil Pithecellobium dulce (Roxb.) seed protein isolate

In this study, the influence of ultrasound on the physicochemical and functional properties of guamuchil seed protein isolate (GSPI) was investigated. The GSPI was prepared by alkaline extraction and isoelectric precipitation method followed by treating with ethanol (95%), from defatted guamuchil seed flour. GSPI suspensions (10%) were sonicated with a probe (20 kHz) at 3 power levels (200 W, 400 W, 600 W) for 15 and 30 min, in addition, to control treatment without ultrasound. Moisture content, water activity, bulk and compact densities and the L*, a* and b* color parameters of the GSPI decreased due to the ultrasound. Glutelin (61.1%) was the main protein fraction in GSPI. Results through Fourier transform infrared and fluorescence spectroscopy showed that ultrasound modified the secondary and tertiary protein structures of GSPI, which increased the surface hydrophobicity, molecular flexibility and in vitro digestibility of GSPI proteins by up to 114.8%, 57.3% and 12.5%, respectively. In addition, maximum reductions of 11.9% in particle size and 55.2% in turbidity of GSPI suspensions, as well as larger and more porous aggregates in GSPI lyophilized powders were observed by ultrasound impact. These structural and physicochemical changes had an improvement of up to 115.5% in solubility, 39.8% in oil absorption capacity, while the increases for emulsifying, foaming, gelling, flow and cohesion properties of GSPI were 87.4%, 74.2%, 40.0%, 44.4%, and 8.9%, respectively. The amelioration of the functional properties of GSPI by ultrasound could represent an alternative for its possible use as a food ingredient in industry.

Potato protein: current review of structure, technological properties, and potential application on spray drying microencapsulation

Studies regarding spray drying microencapsulation are aplenty available; especially focusing on processing parameters, microparticle characteristics and encapsulation efficiency. Hence, there is a rising interest in tailoring wall materials aiming to improve the process's effectiveness. Reflecting a market trend in the food industry, plant-based proteins are emerging as alternative protein sources, and their application adaptability is an increasing research of interest related to consumers' demand for healthy food, product innovation, and sustainability. This review presents a perspective on the investigation of potato protein as a technological ingredient, considering it a nonconventional source obtained as by-product from starch industry. Furthermore, this piece emphasizes the potential application of potato protein as wall material in spray drying encapsulation, considering that this purpose is still limited for this ingredient. The literature reports that vegetal-based proteins might present compromised functionality due to processing conditions, impairing its technological application. Structural modification can offer a potential approach to modify potato protein configuration aiming to improve its utilization. Studies reported that modified proteins can perform as better emulsifiers and antioxidant agents compared to intact proteins. Hence, it is expected that their use in microencapsulation would improve process efficiency and protection of the core material, consequently delivering superior encapsulation performance.

Novel Insights on the Sustainable Wet Mode Fractionation of Black Soldier Fly Larvae (Hermetia illucens) into Lipids, Proteins and Chitin

The black soldier fly larvae (BSFL) is a sustainable ingredient for feed applications, biofuels, composite materials and other biobased products. Processing BSFL to obtain lipid and protein fractions with enhanced functional properties as a suitable replacement for conventional feed ingredients has gained considerable momentum. In this regard, a novel and sustainable wet mode fractionation (WMF) scheme for BSFL was explored. Fresh BSFL were steam blanched and pulped to obtain BSFL juice and juice press cake. Subsequent treatment of BSFL juice employing homogenization or enzyme incubation and further centrifugation resulted in the obtention of four different BSFL fractions (Lipid—LF; Cream—CF; Aqueous—AF; and Solid—SF). Total energy consumption for a batch BSFL (500 g) WMF process was 0.321 kWh. Aqueous and solid fractions were the predominant constituents of BSFL juice. Lauric acid (44.52–49.49%) and linoleic acid (19.12–20.12%) were the primary fatty acids present in BSFL lipids. Lipid hydrolysis was observed in lipids belonging to the solid (free fatty acids > triacylglycerides) and cream fractions. Aqueous fraction proteins (ctrl) displayed superior emulsion stability and foam capacity than other treatments. Juice press cake retained 60% of the total chitin content and the rest, 40%, was found in the solid fraction (ctrl). The material distribution of principal constituents in different fractions of the WMF process and amino acid profile was elucidated. Overall, the versatile WMF process proposed in this study involves simple unit operations to obtain functional ingredients from BSFL, which can be further explored by researchers and industry stakeholders.

Ginkgo Seed Proteins: Characteristics, Functional Properties and Bioactivities

Ginkgo biloba L. is an ancient plant relic, which is known as a "living fossil", and is widely cultivated in China. This plant with medical potential and health benefits has drawn the attention of researchers. Ginkgo seeds are rich in protein. Ginkgo seed proteins (GSPs) have good functional properties over many other seed proteins, which have the potential to be utilized as food ingredients. Moreover, GSP contains no restricted amino acids and is easy to be separated. Several GSP isolate with various bioactivities, such as antimicrobial and antioxidative activities, have been purified and evaluated for their bioactive potential. In this review, the separation methods and bioactivities of GSP were summarized, physicochemical characteristics and functional properties were comprehensively reviewed and compared with other seed proteins. Some food applications of GSP were also briefly introduced. Besides, some suggestions and prospects were discussed in this review.

Improving the Functionality of Proso Millet Protein and Its Potential as a Functional Food Ingredient by Applying Nitrogen Fertiliser

Nitrogen is required for proso millet growth and has a critical influence on yield and quality. However, the effect of nitrogen fertilisation on proso millet protein properties remains unclear. This study aimed to investigate how nitrogen fertiliser treatment (180 kg/hm²) affects the structural and functional properties of proso millet protein. In comparison with the control group (N0), nitrogen fertiliser treatment loosened the dense structure of the protein and presented a larger particle size. Nitrogen treatment did not change the main subunit composition, and β-sheet and α-helix were the main secondary structures of proso millet protein based on Fourier transform infrared spectroscopy. In addition, nitrogen fertiliser treatment improved the content of hydrophobic amino acids and β-sheet proportion from proso millet protein, and high water/oil absorption capacity and thermal stability was observed, but the solubility, emulsion stability and foaming properties from proso millet protein decreased. Proso millet proteins exhibited high amino acid content and good functional properties, including solubility, foaming capacity and emulsifying properties, especially the w139 variety. Results show that proso millet protein has great potential for food applications. The above results provide useful information for the food industry to determine emerging gluten-free protein resources.

Metabolomic and Confocal Laser Scanning Microscopy (CLSM) Analyses Reveal the Important Function of Flavonoids in Amygdalus pedunculata Pall Leaves With Temporal Changes

Amygdalus pedunculata Pall [Rosaceae, Prunus, Prunus pedunculata (Pall.) Maxim.] belongs to the Rosaceae family and is resistant to cold and drought. Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry and metabolomics were used to track the changes in bioactive metabolites during several stages of Amygdalus pedunculata Pall growth. A total of 827 different metabolites were detected, including 169 flavonoids, 68 organic acids, 35 terpenoids and 2 tannins. Flavonoid biosynthesis and flavone and flavonol biosynthesis were the main synthetic sources of flavonoids. Quercetin, isoquercitrin, and epicatechin as biomarkers related to growth and development were found. Quercetin connects the biosynthesis of flavonoids and the biosynthesis of flavones and flavonols. The contents of isoquercitrin and epicatechin increased uniformly during the whole growth process from the flowering stage to the fruit ripening stage, indicating that play key roles in the fruit growth and ripening stages of this plant. The tissue location and quantitative analysis of flavonoids in leaves at different stages were performed by confocal laser scanning microscopy. The flavonoids were mainly distributed in the palisade tissue and spongy tissue, indicating the need for protection of these sensitive tissues in particular. Through comprehensive and systematic analysis, the temporal distribution of flavonoids in the process of their leaves growth was determined. These results clarify the important role of flavonoids in the developmental process of Amygdalus pedunculata Pall.

Dynamic transcriptome analysis identifies genes related to fatty acid biosynthesis in the seeds of Prunus pedunculata Pall

BACKGROUND

Prunus pedunculata Pall, the deciduous shrub of Amygdalus subgenus in Rosaceae, is a new kind of desert oil-bearing tree. It has a long story of being planted in the West and North of China for sand fixation and desert control. In addition, the seeds of P. pedunculata are rich of oil, especially the monounsaturated fatty acid and polyunsaturated fatty acid. However, little is known about the molecular mechanisms of oil accumulation during the seed development of P. pedunculata.

RESULTS

The seeds of P. pedunculata from three independent plants at 10, 18, 24, 31, 39, 45, 59 and 73 days after flowering (DAF) were obtained and the oil compositions were evaluated. It showed that oleic acid was the dominant type of oil content in the mature seeds (from 32.724% at 10DAF to 72.06% at 73DAF). Next, transcriptome sequencing for the developing seeds produced 988.795 million high quality reads and TRINITY assembled 326,271 genes for the first transcriptome for P. pedunculata. After the assembled transcriptome was evaluated by BUSCO with 85.9% completeness, we identified 195,342, 109,850 and 121,897 P. pedunculata genes aligned to NR, GO and KEGG pathway databases, respectively. Then, we predicted 23,229 likely proteins from the assembled transcriptome and identified 1917 signal peptides and 5512 transmembrane related proteins. In the developing seeds we detected 91,362 genes (average FPKM > 5) and correlation analysis indicated three possible development stages - early (10 ~ 24DAF), middle (31 ~ 45DAF) and late (59 ~ 73DAF). We next analyzed the differentially expressed genes (DEGs) in the developing seeds. Interestingly, compared to 10DAF the number of DEGs was increased from 4406 in 18DAF to 27,623 in 73DAF. Based on the gene annotation, we identified 753, 33, 8 and 645 DEGs related to the fatty acid biosynthesis, lipid biosynthesis, oil body and transcription factors. Notably, GPAT, DGD1, LACS2, UBC and RINO were highly expressed at the early development stage, ω6-FAD, SAD, ACP, ACCA and AHG1 were highly expressed at the middle development stage, and LACS6, DGD1, ACAT1, AGPAT, WSD1, EGY2 and oleosin genes were highly expressed at the late development stage.

CONCLUSIONS

This is the first time to study the developing seed transcriptome of P. pedunculata and our findings will provide a valuable resource for future studies. More importantly, it will improve our understanding of molecular mechanisms of oil accumulation in P. pedunculata.

Structural, physicochemical and functional properties of Semen Ziziphi Spinosae protein

Semen Ziziphi Spinosae (Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chou) is a functional food and a traditional Chinese medicine (TCM) in China. Herein, Semen Ziziphi Spinosae protein (SZSP) was prepared by an alkaline extraction and acid precipitation method, of which the structural, physicochemical, functional and emulsion properties were investigated. Results showed that SZSP contained an ideal amino acid composition. The structural properties of the proteins were characterized using Fourier transform infrared spectroscopy (FTIR), relative fluorescence and circular dichroism (CD) spectroscopy analysis. The electrophoresis profiles showed that the main molecular weight of the protein components was about 10-40 kDa and contained some glycoproteins. Differential scanning calorimetry analysis indicated that the denaturation temperature of SZSP was 110.5 °C. The functional properties showed that SZSP has good water and oil absorption capacity, high emulsifying ability and foaming stability. The overall results suggest that SZSP is a promising protein source for the functional food industry.