scholarly journals Isolation, Structural and Functional Characterization of Jackfruit (Artocarpus heterophyllus Lam) Seed Proteins

2020 ◽  
Vol 18 (1) ◽  
pp. 103-115
Author(s):  
Fatema Akter ◽  
M Amdadul Haque ◽  
M Abdul Baqui

With increasing health awareness, the demand for concentrated proteins from plant sources has been rising for direct consumption or to use as an ingredient in food formulation. The characteristic information of any component is prerequisite for its efficient usage in food preparation. This study was undertaken to isolate the protein from jackfruit seeds and characterizing the physicochemical and functional properties of the isolated protein. The protein fraction from jackfruit seed flour was isolated using pH treatments and centrifugation process. The isolated protein was converted into powder form by a vacuum drying and grinding method. Total protein content in the isolate was determined by the Kjeldahl method. The functional properties such as solubility and gelling capacity and secondary structural elements of jackfruit seed protein isolate (JSPI) were studied. The crude JSPI contained 76.89% protein with 58.44% solubility in aquatic solvent. The conformational study by Fourier-transform infrared spectroscopy (FTIR) indicated that the β -sheet is the dominant secondary structure of JSPI that contained 50.28% β -sheet, 21.71% α -helix, 8.86% β -turn, and 19.15% unordered structure. The least gelation concentration of JSPI dissolved in 1.0 M NaCl solution was 12%. The pH of the solvent significantly affected the emulsifying and foaming properties (p<0.05). Based on the observed structural and functional features, JSPI has prospects to be used as a supplementary ingredient in future food formulations. The Agriculturists 2020; 18(1) 103-115

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Na Thi Ty Ngo ◽  
Fereidoon Shahidi

AbstractCamelina and flixweed (sophia) seed protein isolates were prepared using both the conventional extraction and ultrasonic-assisted extraction methods at 40 kHz for 20 min, and their functional properties investigated. SDS-PAGE showed that both ultrasound-assisted and conventional extractions resulted in a similar protein profile of the extract. The application of ultrasound significantly improved protein extraction/content and functional properties (water holding capacity, oil absorption capacity, emulsifying foaming properties, and protein solubility) of camelina protein isolate and sophia protein isolate. The water-holding and oil absorption capacities of sophia protein isolate were markedly higher than those of camelina protein isolate. These results suggest that camelina protein isolate and sophia protein isolate may serve as natural functional ingredients in the food industry. Graphical Abstract


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2618 ◽  
Author(s):  
Xiaotong Sun ◽  
Hua Jin ◽  
Yangyang Li ◽  
Haiying Feng ◽  
Chunhong Liu ◽  
...  

This study aimed to investigate the variation of molecular functional properties of peanut protein isolate (PPI) over the storage process and reveal the correlation between the PPI secondary structure and properties in the storage procedure. After storage, the molecular properties of PPI changed significantly (p < 0.05). Extending storage time resulted in a decrease in free sulfhydryl content, fluorescence intensity, surface hydrophobicity and emulsifying properties, which was accompanied by an increase in protein particle size. The results of infrared spectroscopy suggested the content decline of α-helix and β-sheet, and the content rise of β-turn and random coil. Based on bivariate correlation analysis, it was revealed that surface hydrophobicity and emulsifying activity of PPI was significantly affected by α-helix and by β-turn (p < 0.05), respectively. This research supplied more information for the relationship between the peanut protein’s secondary structure and functional properties over the stored process.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1332
Author(s):  
Honglu Wang ◽  
Dongmei Li ◽  
Chenxi Wan ◽  
Yan Luo ◽  
Qinghua Yang ◽  
...  

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.


2020 ◽  
Vol 12 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Muhammad Elsayed Elsorady

Flaxseed protein isolate (FPI) and sesame protein isolate (SPI) were extracted from flaxseed and sesame cake as by-products, and their functional properties (water holding and fat absorption capacities, bulk density, least gelling concentration, solubility, and emulsifying properties) were determined. Bulk density of the SPI (0.162 g/ml) was lower than that of the FPI (0.175 g/ml). The water absorption capacity of the FPI (305.66%) was higher than that of the SPI (288.93%). The oil absorption capacity and least gelling capacity of the FPI and SPI were 127.48, 3.6, 134.39, and 5%, respectively. The least solubility occurred at pH 4.0 and it was 24.54, 9.56% for FPI and SPI, respectively. Levels of pH and salt concentrations were used as dependent variables for the characterization of emulsifying capacity, activity, and emulsion stability, as well as foaming capacity and foam stability. The addition of NaCl at concentrations up to 1.0 M improved these characteristics. The SPI and FPI had a minimum emulsion capacity (74.54 and 100.20 ml oil/g protein, respectively) and a minimum foam capacity (14.25 and 17.35 %, respectively) at pH 4. The FPI and SPI were found to be highly soluble at acidic and alkaline pH and their emulsifying and foaming properties were high. Moreover, their bulk density, water absorption, and fat absorption capacities and least gelling capacity properties were good. Therefore, the FPI and SPI can be used in food formulation systems.


2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
César Ozuna ◽  
Ma. Fabiola León-Galván

Seeds from Cucurbitaceae plants (squashes, pumpkins, melons, etc.) have been used both as protein-rich food ingredients and nutraceutical agents by many indigenous cultures for millennia. However, relatively little is known about the bioactive components (e.g., peptides) of the Cucurbitaceae seed proteins (CSP) and their specific effects on human health. Therefore, this paper aims to provide a comprehensive review of latest research on bioactive and functional properties of CSP isolates and hydrolysates. Enzymatic hydrolysis can introduce a series of changes to the CSP structure and improve its bioactive and functional properties, including the enhanced protein solubility over a wide range of pH values. Small-sized peptides in CSP hydrolysates seem to enhance their bioactive properties but adversely affect their functional properties. Therefore, medium degrees of hydrolysis seem to benefit the overall improvement of bioactive and functional properties of CSP hydrolysates. Among the reported bioactive properties of CSP isolates and hydrolysates, their antioxidant, antihypertensive, and antihyperglycaemic activities stand out. Therefore, they could potentially substitute synthetic antioxidants and drugs which might have adverse secondary effects on human health. CSP isolates and hydrolysates could also be implemented as functional food ingredients, thanks to their favorable amino acid composition and good emulsifying and foaming properties.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Natalia del Carmen Espinosa-Murillo ◽  
José Armando Ulloa ◽  
Judith Esmeralda Urías-Silvas ◽  
Petra Rosas-Ulloa ◽  
José Carmen Ramírez-Ramírez ◽  
...  

Abstract A protein isolate from passion fruit seeds (PFSPI) obtained by alkaline extraction and isoelectric precipitation was treated with sonication for 15 and 30 min at 40 kHz to evaluate its impact on the physicochemical and functional properties. The PFSPI had a purity of 96.21% protein, with albumins being the main fraction (75.66%). Ultrasound increased the bulk density (ρ) of PFSPI by 13.3% and the formation a more porous structure by a greater separation between particles. Protein solubility of PFSPI in the range of pH 2–12 sonicated for 15 and 30 min, increased on average 5.21 and 9.86%, respectively, in comparison with the control. PFSPI foaming properties were influenced by pH and sonication time, achieving up to 577%, while the minimum gelling concentration was reduced from 4 to 2% at pH 7. Therefore, sonication treatment improved some functional properties of PFSPI for its potential use as a food ingredient.


Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4337 ◽  
Author(s):  
Li Tan ◽  
Pengzhi Hong ◽  
Ping Yang ◽  
Chunxia Zhou ◽  
Dinghao Xiao ◽  
...  

The secondary structure of a protein has been identified to be a crucial indicator that governs its water solubility. Tilapia protein isolate (TPI), soybean protein isolate (SPI), and tilapia-soybean protein co-precipitates (TSPC3:1, TSPC2:1, TSPC1:1, TSPC1:2, and TSPC1:3) were prepared by mixing tilapia meat and soybean meal at different mass ratios. The results demonstrated that the water solubility of TSPCs was significantly greater than that of TPI (p <0.05). The changes in ultraviolet–visible and near-ultraviolet circular dichroism spectra indicated that the local structure of TSPCs was different from that of TPI and SPI. Fourier transform infrared Spectroscopy revealed the co-existence of TPI and SPI structures in TSPCs. The secondary structures of TSPCs were predominantly α-helix and β-sheet. TSPC1:1 was unique compared to the other TSPCs. In addition, there was a good correlation between the water solubility and secondary structure of TSPCs, in which the correlation coefficients of α-helix and β-sheet were −0.964 (p <0.01) and 0.743, respectively. TSPCs displayed lower α-helix contents and higher β-sheet contents compared to TPI, which resulted in a significant increase in their water solubility. Our findings could provide insight into the structure–function relationship of food proteins, thus creating more opportunities to develop innovative applications for mixed proteins.


Author(s):  
Jogendra Singh Nim ◽  
Mohit Yadav ◽  
Lalit Kumar Gautam ◽  
Chaitali Ghosh ◽  
Shakti Sahi ◽  
...  

Background: Xenorhabdus nematophila maintains species-specific mutual interaction with nematodes of Steinernema genus. Type II Toxin Antitoxin (TA) systems, the mazEF TA system controls stress and programmed cell death in bacteria. Objective: This study elucidates the functional characterization of Xn-mazEF, a mazEF homolog in X. nematophila by computational and in vitro approaches. Methods: 3 D- structural models for Xn-MazE toxin and Xn-MazF antitoxin were generated, validated and characterized for protein - RNA interaction analysis. Further biological and cellular functions of Xn-MazF toxin were also predicted. Molecular dynamics simulations of 50ns for Xn-MazF toxin complexed with nucleic acid units (DU, RU, RC, and RU) were performed. The MazF toxin and complete MazEF operon were endogenously expressed and monitored for the killing of Escherichia coli host cells under arabinose induced tightly regulated system. Results: Upon induction, E. coli expressing toxin showed rapid killing within four hours and attained up to 65% growth inhibition, while the expression of the entire operon did not show significant killing. The observation suggests that the Xn-mazEF TA system control transcriptional regulation in X. nematophila and helps to manage stress or cause toxicity leading to programmed death of cells. Conclusion: The study provides insights into structural and functional features of novel toxin, XnMazF and provides an initial inference on control of X. nematophila growth regulated by TA systems.


2020 ◽  
Vol 01 ◽  
Author(s):  
Zheng Zuo ◽  
Zongyun Chen ◽  
Zhijian Cao ◽  
Wenxin Li ◽  
Yingliang Wu

: The scorpion toxins are the largest potassium channel-blocking peptide family. The understanding of toxin binding interfaces is usually restricted by two classical binding interfaces: one is the toxin α-helix motif, the other is the antiparallel β-sheet motif. In this review, such traditional knowledge was updated by another two different binding interfaces: one is BmKTX toxin using the turn motif between the α-helix and antiparallel β-sheet domains as the binding interface, the other is Ts toxin using turn motif between the β-sheet in the N-terminal and α-helix domains as the binding interface. Their interaction analysis indicated that the scarce negatively charged residues in the scorpion toxins played a critical role in orientating the toxin binding interface. In view of the toxin negatively charged amino acids as “binding interface regulator”, the law of scorpion toxin-potassium channel interaction was proposed, that is, the polymorphism of negatively charged residue distribution determines the diversity of toxin binding interfaces. Such law was used to develop scorpion toxin-potassium channel recognition control technique. According to this technique, three Kv1.3 channel-targeted peptides, using BmKTX as the template, were designed with the distinct binding interfaces from that of BmKTX through modulating the distribution of toxin negatively charged residues. In view of the potassium channel as the common targets of different animal toxins, the proposed law was also shown to helpfully orientate the binding interfaces of other animal toxins. Clearly, the toxin-potassium channel interaction law would strongly accelerate the research and development of different potassium channelblocking animal toxins in the future.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ukrit Thamma ◽  
Tia J. Kowal ◽  
Matthias M. Falk ◽  
Himanshu Jain

AbstractThe nanostructure of engineered bioscaffolds has a profound impact on cell response, yet its understanding remains incomplete as cells interact with a highly complex interfacial layer rather than the material itself. For bioactive glass scaffolds, this layer comprises of silica gel, hydroxyapatite (HA)/carbonated hydroxyapatite (CHA), and absorbed proteins—all in varying micro/nano structure, composition, and concentration. Here, we examined the response of MC3T3-E1 pre-osteoblast cells to 30 mol% CaO–70 mol% SiO2 porous bioactive glass monoliths that differed only in nanopore size (6–44 nm) yet resulted in the formation of HA/CHA layers with significantly different microstructures. We report that cell response, as quantified by cell attachment and morphology, does not correlate with nanopore size, nor HA/CHO layer micro/nano morphology, or absorbed protein amount (bovine serum albumin, BSA), but with BSA’s secondary conformation as indicated by its β-sheet/α-helix ratio. Our results suggest that the β-sheet structure in BSA interacts electrostatically with the HA/CHA interfacial layer and activates the RGD sequence of absorbed adhesion proteins, such as fibronectin and vitronectin, thus significantly enhancing the attachment of cells. These findings provide new insight into the interaction of cells with the scaffolds’ interfacial layer, which is vital for the continued development of engineered tissue scaffolds.


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