scholarly journals Enhanced Solubility of Rapeseed Meal Protein Isolates Prepared by Sequential Isoelectric Precipitation

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 703
Author(s):  
Hristo Kalaydzhiev ◽  
Radoslav Georgiev ◽  
Petya Ivanova ◽  
Magdalena Stoyanova ◽  
Cristina L. M. Silva ◽  
...  

The solubility of plant protein isolates is a key determinant of their potential application. Two protein isolates (PI) from ethanol-treated industrial rapeseed meal, PI10.5–2.5 and PI2.5–8.5, were prepared by sequential isoelectric precipitation of alkali-extracted proteins (pH 12) starting from pH 10.5 to 2.5 or from pH 2.5 to 8.5, respectively. Biochemical analyses revealed that PI2.5–8.5 contained a higher amount of crude protein (72.84%) than PI10.5–2.5 (68.67%). In the same protein isolate, the level of total phenols (0.71%) was almost two-fold higher than that in PI10.5–2.5 (0.42%). No glucosinolates were established in both protein isolates. SDS-PAGE analysis demonstrated that PI10.5–2.5 contained 10 to 15 kDa protein fractions in a relatively higher amount, while PI2.5–8.5 was enriched in 18 to 29 kDa protein fractions. PI10.5–2.5 exhibited high solubility, varying from 41.74% at pH 4.5 to 65.13% at pH 6.5, while PI2.5–8.5 was almost two-fold less soluble under the same conditions. Up to pH 5.5, the addition of NaCl at 0.03 and 0.25 M diminished the solubility of PI2.5–8.5, while the solubility of PI10.5–2.5 was increased. The supplementation of PI10.5–2.5 with 0.25 M NaCl enhanced the protein solubility to 56.11% at pH 4.5 and 94.26% at pH 6.5. The addition of 0.03 M NaCl also increased the solubility of this protein isolate but to a lower extent. Overall, the approach for sequential precipitation of proteins influenced the biochemical characteristics, protein fractional profile and solubility of prepared protein isolates.

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


2019 ◽  
Vol 56 (6) ◽  
pp. 3090-3098
Author(s):  
Hristo Kalaydzhiev ◽  
Vanya D. Gandova ◽  
Petya Ivanova ◽  
Teresa R. S. Brandão ◽  
Tzvetelin T. Dessev ◽  
...  

1979 ◽  
Vol 6 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Esam M. Ahmed ◽  
Ronald H. Schmidt

Abstract Proteins were extracted from defatted Florunner peanuts and Cobb soybeans and dried using different methods. Freshly prepared peanut protein isolates contained 73.9 to 81.3% protein and 1.4 to 4.3% fat. The corresponding values for soybeans were 54.7 to 61.6% and 2.7 to 4.5%. Spray dried peanut protein isolate contained 69.1% protein after 36 months storage and exhibited less solubility than those stored for 24 months or freshly prepared. Freeze dried soybean isolate contained more soluble protein man the freeze dried peanut protein isolate. The reverse was true for the spray dried peanut and soybean isolates. Protein solubility, emulsifying capacity, foaming capacity and foam stability of peanut and soybean protein isolates were higher for the spray dried and freeze dried than the drum dried preparations. Heat treatment of peanuts (107°C for 20 min.) did not influence protein solubility or emulsifying capacity but decreased foaming capacity and foam stability. Storage of peanut isolates resulted in a loss of emulsifying capacity, especially for the freeze dried peanut preparation.


Author(s):  
Oseni Kadiri ◽  
Saka O Gbadamosi ◽  
Babatunde Olawoye ◽  
Charles T Akanbi

The effect of different processing stages- defatting, solubilization, isoelectric precipitation, neutralisation and lyophilisation on the total phenolic content and protein content of Carica papaya (pawpaw) seeds (CPS) full-fat flour (CFF), defatted flour (CDF), protein concentrates (CPC) and protein isolates (CPI) was studied. The folin-ciocalteu procedure was used to assess the total phenolic concentrations of the Carica papaya products and results were expressed as gallic acid equivalent (GAE). Optimal protein content was estimated at pH 10 for all samples. Higher levels of polyphenols were extracted using water-methanol (20/80) mixture compared to 100% methanol. Total phenolic content (TPC) was demonstrated in a trend of CDF > CPC > CFF > CPI with CDF having the highest TPC. The finding suggested a more economical protein isolate production method. The study concludes that the processing of CPS into the various products (CFF, CDF, CPC & CPI) improves its protein and polyphenol content.


2020 ◽  
Vol 21 (4) ◽  
pp. 408-416
Author(s):  
S. V. Bobkov ◽  
O. V. Uvarova

The article provides the results of the experiments on determination of optimal parameters for obtaining isolated proteins from grains of cultivated and wild pea for use in breeding for quality. The flour of pea varieties Sophia, Rodnik and wild accession k-3370 (Pisum sativum L. ssp. Elatius) were used in the experiment. Isolated pea proteins were obtained based on alkaline extraction and isoelectric precipitation. The experiments were carried out with the use of complete and fractional factorial plans with two levels of factors. Extraction and precipitation of protein were conducted in two stages. One hundred grams of flour were used for extraction. Influence of factors (variety, pH, duration of extraction) on the yield of isolated protein, extraction efficiency, crude protein and fat content in protein isolates was studied. All isolates were characterized by high content of crude protein (90.2-93.1 %). It was determined that increase of pH higher than eight led to enhancement of protein yield and decrease of crude protein content. The results obtained raise the possibility of effective extraction at decreased level of pH that prevents the formation of toxic chemicals. Increase of pH promoted fat accumulation in protein isolate especially at the second stage of extraction. Thus, obtaining protein isolates for evaluation of pea genetic resources should be conducted during a single cycle of extraction and precipitation. The experiments have not revealed significant differences between cultivated and wild pea as to the technology of extraction. The results of the studies are important for evaluation of pea genetic resources according to functional properties of protein isolates.


Author(s):  
Sobhy Ahmed El Sohaimy ◽  
Marageta A. Brennan ◽  
Amira Galal Darwish ◽  
Charles S. Brennan

The aim of this study was to enhance the nutritional value and the functional characteristics of muffins by enriching with chickpea protein isolate, while keeping their rheological characteristics. Chickpea Protein isolate (CPI) was prepared by alkaline solubilization (pH 11), followed by isoelectric precipitation at pH 4.5. SDS-PAGE revealed three subunits with molecular weights of 47, 30 and 85 kDa; representing the globulin fractions, legumin-like and vicilin-like proteins. Maximum protein solubility (83.32%) was obtained at pH 11. CPI exhibited an emulsifying activity index of 25.17 m2 g-1, emulsion stability index of 14.09 min. The foaming capacity and stability were 62% and 94.49%, respectively. Water and oil absorption were 3.65 and 2.30 mL g-1, respectively. CPI was added to muffin batter at 0, 2.5, 5, 7.5 and 10%. CPI fortifieded muffins showed reduction in moisture content, which influenced texture profile analysis through increasing hardness, gumminess and chewiness values. Additionally, both protein content and protein digestibility of muffins increased to 22.2 and 94.08%, respectively. CPI-enriched muffins were darker (lower L) with yellowish crumbs (higher b). Finally, preliminary sensory evaluation showed high consumer acceptance for CPI-enriched muffins.


2018 ◽  
Vol 6 (1) ◽  
pp. 18 ◽  
Author(s):  
Nur Fauziah Matra ◽  
Endah Puspitasari ◽  
Tri Agus Siswoyo

Hypertension is ranked third on the cause of death in Indonesia for all ages (6.8 %). Protein isolate of melinjo seeds (Gnetum gnemon L.) hydrolyzed with free alcalase has been known to have antihypertensive activity. However, the use of free alcalase is uneconomical since it can only be used once, thus we studied the immobilized alcalase effectivity to hydrolise the melinjo seeds protein isolate to be used as angiotensin converting enzyme (ACE) inhibitor. The immobilization method used entrapment method with DMDMOS/TMOS as matrix. Characterization of the immobilized enzyme was observed by FTIR and effectiveness of repeated hydrolysis was observed by the value of the degree of hydrolysis. The success of the hydrolysis process was determined by SDS-PAGE electrophoresis. Antihypertensive activity test was determined by the ability to inhibit ACE. The results showed that the alcalase has been immobilized in the matrix of silane and SDS-PAGE protein profile showed melinjo seed proteins had been successfully hydrolyzed. Hydrolysis process repeatedly demonstrated that immobilized alcalase was effective to hydrolyze protein isolates of melinjo seeds twice. Based on ACE inhibitory test, there were no significant differences between the protein isolate hydrolyzed by immobilized alcalase (Gg-PH), protein isolates hydrolyzed with free alcalase (Gg-PHB), and captopril. These findings suggest that the antihypertensive activity in Gg-PH is the same with that of captopril.   Keywords: hypertension, antihypertensive, melinjo, enzymes immobilization, ACE inhibitor    


Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5853
Author(s):  
Tuong Thi Le ◽  
Xavier Framboisier ◽  
Arnaud Aymes ◽  
Armelle Ropars ◽  
Jean-Pol Frippiat ◽  
...  

In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry.


Author(s):  
Raul IANCHICI ◽  
Rodica SEGAL ◽  
Simona CRISAN ◽  
Monica ZDREMTAN

Pea’s proteins represent a valuable source of edible proteins which are well tolerating by human body, and contain all essential amino acids. Mature pea’s seeds are very rich in proteins that can be extracted in order to be used to improve the nutritional value of other foods. Pea’s proteins contain several fractions of albumins and globulins. We have used electrophoresis to separate and identify these fractions, to establish the molecular weight of each fraction, and also the proportion between them. The electrophoresis was conducted following the SDS-PAGE protocol. Using pea protein isolate as sample, we have found a number of 12 protein fractions with molecular weights ranging between 12500 and 140000 Daltons. From these, six fractions are prevalent.


2014 ◽  
Vol 3 (2) ◽  
Author(s):  
Petia Ivanova ◽  
Vesela Ivanova Chalova ◽  
Lidia Koleva

Protein isolate 1 (PI1) and protein isolate 2 (PI2) were prepared from industrially produced sunflower meal by using isoelectric and ethanol precipitation respectively. The water absorption capacity of PI1 was 6 times higher than that of PI2 and was significantly reduced by the presence of 0.03 M and 0.25 M NaCl. Oil absorption capacity of both protein isolates was not influenced by NaCl supplementation. Foam capacity of PI1 and PI2 was pH-dependent. While the foam capacity of both isolates was improved by either 0.03 M or 0.25 M NaCl, the foam stability was negatively influenced by the addition of NaCl at all pH values with except for pH 4. Emulsifying activity of PI1 and PI2 was lowest at pH 4. The emulsions exhibited relatively high stability (> 90%) under all studied conditions. Knowledge of the influence of pH and boundary concentrations of NaCl on the functionality of sunflower meal protein isolates could be beneficial for their future potential application in food industry.


Sign in / Sign up

Export Citation Format

Share Document