Isoelectric Precipitation
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2021 ◽  
Vol 13 (1) ◽  
pp. 85-94
Author(s):  
Bayan Y . AL-Abdulla1 ◽  

The purpose of this study was to determine the effect of lupine flour (L.f) and lupine protein concentrate (L.P.C) incorporation on chemical, nutritional and sensual qualities characteristics of biscuit (L.P.C) was prepared by isoelectric precipitation method. A standard recipe for biscuit preparation by wheat patent flour used as the control. Wheat flour in the control treatment was replaced with (L.f) and (L.P.C) at levels 10, 20 & 30%. Chemical composition of (L.f), (L.P.C) and biscuit treatments were studied. Results showed that protein contents were 35.35 & 75.80% for (L.F) and (L.P.C), respectively. While they amounted to 14.70, 16.16 & 18.61% for (L.f) incorporated biscuits and 15.20, 18.09 & 21.08% for (L.P.C) incorporated biscuits at the substitution levels studied, respectively compared 12.43% control. Results also indicated contents of total dietary fibers and tannins in (L.f),( L.P.C) and biscuits prepared. Sensory evaluation of biscuit treatments revealed that there was significant decrease at substitution level up to 30% of (L.f) except color score, while all scores of sensory properties were improved significantly at all substitution levels of (L.P.C). Spread ratio was affected adversely by incorporation of (L.f) and slightly when (L.P.C) used. Results showed a reduction in biscuit tenderness during storage. Reverse to the above statement with 30% incorporation of (L.f) while increased at (L.P.C) treatments. The study demonstrated that (L.f) and (L.P.C) can be incorporated into biscuits formulation by replacing up to 20, & 30% of wheat flour control 12.43%, respectively to increase dietary fiber and protein contents.


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.


2021 ◽  
Vol 57 (3) ◽  
pp. 83-101
Author(s):  
I. Paladii ◽  
◽  
Е. Vrabie ◽  
C. Sprincean ◽  
Mircea Bologa ◽  
...  

The current state of the art on studying of whey is considered. The processes and methods of whey processing (thermal, chemical, physicochemical, biotechnological, and electrophysical) are presented. Thermal and isoelectric precipitation of proteins, using reagents and coagulants, as well as the main membrane processing methods (reverse osmosis, diafiltration, microfiltration, ultrafiltration, and nanofiltration) are described. Possibi-lities of effective separation of whey proteins by a combination of membrane and other methods are noted. Chromatographic methods for fractionation of whey proteins (chromatography with imitation of a moving bed, high-gradient chromatography with a magnetic trap, selective adsorption, displacement chromatography, membrane adsorption), which provide a high degree of separation, are described. Highly porous chromatographic materials providing a high flow rate, biotechnological processing methods – biosynthesis of lactulose, enzymatic hydrolysis of lactose and whey proteins, aerobic and anaerobic fermentation are considered. Electrophysical methods of processing whey (electrodialysis, electroactivation), which include electrodialysis and electro-activation, as well as electrochemical activation as a phenomenon and technology, as a new promising processing method that allows to create a waste-free cycle for obtaining valuable components and useful derivatives from whey without the use of reagents are analyzed. It is emphasized that, depending on the regimes used, protein-mineral concentrates with a predetermined protein or mineral composition are obtained with the simultaneous isomerization of lactose into lactulose. It is stated that the efficiency of methods for processing whey is ensured by a significant increase in the efficiency of technological processes, a decrease in labor costs, a reduction in the processing time and materials, and an improvement in the quality and functional properties of the final products.


2021 ◽  
Author(s):  
Sunny Kalyan ◽  
SUNITA MEENA ◽  
Suman Kapila ◽  
Radha Yadav ◽  
Gaurav Kr Deshwal

Abstract The present study was executed with an aim to explore the antioxidative potential of goat, cow, and buffalo milk. Buffalo milk has showed highest antioxidative potential than goat and cow milk as measured by ABTS, ORAC, and DPPH assays, whereas goat milk has showed better antioxidative potential than cow milk when measured by ORAC and DPPH. Further, the effect of temperature on the antioxidative potential of goat milk was assessed. An increase in temperature has a negatively affect the antioxidative potential of goat milk. The antioxidative potential of goat milk was in the following order: raw milk > pasteurized milk > boiled milk. Casein derived from goat milk by isoelectric precipitation was hydrolyzed by gastrointestinal enzymes pepsin (P), trypsin (T), chymotrypsin (C), and their combinations PT, PC, TC, and PTC. Among all the casein hydrolysates, the maximum antioxidative potential was found in PT hydrolysate, further fractionated by 10, 3 and 1 kDa ultrafiltration membranes. 3–10 kDa fraction exhibited maximum antioxidative potential in comparison to other fractions of PT hydrolysate. Our results suggested that antioxidative potential of goat milk and its hydrolysates could be an important mean to obtain natural antioxidative peptides.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 758
Author(s):  
Verónica García Arteaga ◽  
Sonja Kraus ◽  
Michael Schott ◽  
Isabel Muranyi ◽  
Ute Schweiggert-Weisz ◽  
...  

Pea protein concentrates and isolates are important raw materials for the production of plant-based food products. To select suitable peas (Pisum sativum L.) for protein extraction for further use as food ingredients, twelve different cultivars were subjected to isoelectric precipitation and spray drying. Both the dehulled pea flours and protein isolates were characterized regarding their chemical composition and the isolates were analyzed for their functional properties, sensory profiles, and molecular weight distributions. Orchestra, Florida, Dolores, and RLPY cultivars showed the highest protein yields. The electrophoretic profiles were similar, indicating the presence of all main pea allergens in all isolates. The colors of the isolates were significantly different regarding lightness (L*) and red-green (a*) components. The largest particle size was shown by the isolate from Florida cultivar, whereas the lowest was from the RLPY isolate. At pH 7, protein solubility ranged from 40% to 62% and the emulsifying capacity ranged from 600 to 835 mL g−1. The principal component analysis revealed similarities among certain pea cultivars regarding their physicochemical and functional properties. The sensory profile of the individual isolates was rather similar, with an exception of the pea-like and bitter attributes, which were significantly different among the isolates.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Paolo Passaretti ◽  
Inam Khan ◽  
Timothy R. Dafforn ◽  
Pola Goldberg Oppenheimer

Abstract M13 bacteriophage is a well-established versatile nano-building block, which can be employed to produce novel self-assembled functional materials and devices. Sufficient production and scalability of the M13, often require a large quantity of the virus and thus, improved propagation methods characterised by high capacity and degree of purity are essential. Currently, the ‘gold-standard’ is represented by infecting Escherichia coli cultures, followed by precipitation with polyethylene glycol (PEG). However, this is considerably flawed by the accumulation of contaminant PEG inside the freshly produced stocks, potentially hampering the reactivity of the individual M13 filaments. Our study demonstrates the effectiveness of implementing an isoelectric precipitation procedure to reduce the residual PEG along with FT-IR spectroscopy as a rapid, convenient and effective analytic validation method to detect the presence of this contaminant in freshly prepared M13 stocks.


2020 ◽  
Vol 67 (3) ◽  
Author(s):  
Abhilash Sasidharan ◽  
V. J. Michu ◽  
Chiranjiv Pradhan ◽  
S. Sabu

Threadfin bream (Nemipterus japonicus) is an important marine fish species used in the preparation of surimi. The waste generated from surimi production contains large quantity of recoverable proteins, which could be utilised for byproduct development. In this study, Isoelectric precipitation (IEP) technique as a method to recover proteins from fish processing waste was attempted. The alkali aided IEP process extracted the fish protein isolate (FPI) efficiently with a yield of 84.13±0.11%. The highest protein yield was recorded at a homogenised sample to water ratio of 1:9. Maximum protein content was found at pH 13 with 19.63 ±0.52% yield. FPI extracted had higher protein content, less ash and low lipid contents compared to the fish processing waste. The mean yield and protein composition of FPI extracted atdifferent treatments of pH and sample to water ratiowere found to be significantly different (p<0.05). Sample to water ratio of 1:9 and pH 13 was found to be the best combination among the different treatments attempted for FPI extraction from threadfin bream processing waste.


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.


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