Characterization Of Protein Isolates Research Articles

Ultrasound and enzymatic treatments to improve protein extraction from cress seeds, and the characterization of protein isolates

In this study, proteins were extracted from cress seeds using enzymatic pretreatment and ultrasound. Optimization of enzymatic pretreatment, employing a multi-enzyme complex rich in carbohydrases, aimed to maximize extraction yield and reduce sugar content. Ultrasound replaced classical extraction under optimal conditions by comparing functional properties between enzyme-treated and untreated samples. Combined enzymatic pretreatment and ultrasound significantly increased extraction yield from 39.56% to 94.03%. Optimal enzymatic pretreatment conditions included pH 3.84, 45.16 °C, enzyme concentration 2.32 FBGU/g seed, and 3.71 h of treatment time. Ultrasound-treated isolates exhibited superior functionality and minimal structural changes, with molecular weights ranging from ∼22 kDa to ∼59 kDa. These findings underscore the potential of cress seed protein isolate for diverse applications, enhanced through enzymatic pretreatment and ultrasound, owing to its high nutritional quality.

Characterization of protein isolates from green wheat: structure, thermal and rheological properties

Characterization of protein isolates from green wheat: structure, thermal and rheological properties

Functional properties of the protein isolates of hyacinth bean [Lablab purpureus (L.) Sweet]: An effect of the used procedures

This study investigated the effect of protein isolate preparation procedures on functionality and characterization of protein isolates using salt-extraction dialysis, micellization and isoelectric precipitation. Micellization produced the highest protein content and yield (87.78 and 72.60 g/100g) followed by isoelectric precipitation and salt-extraction dialysis. Isoelectric precipitation gave a significantly higher digestibility (88.47 g/100g) than micellization and salt-extraction, as well as higher water and oil holding capacities (2.48 and 2.99 g/g). However, emulsion capacity (88.89–100%) and stability (20.15–37.00%) were not found to be significantly affected by the extraction method. Salt-extraction gave the highest foaming capacity but lowest foaming stability (123.33 and 27.32%) than isoelectric and micellization precipitation. Isoelectric and micellization precipitation gave better gelling abilities (16%) than salt-extraction. Arginine and lysine contents of isolates were high (12.70–16.59) with protein efficiency ratios for the isolates greater than 2 (2.61–6.66), indicative of a high protein quality. Protein isolates may be useful in supplementing foods that require improved functionality and protein qualities, but extraction procedures play a significant role in the functional properties of the final product.

Characterization of protein isolate from Sesamum indicum seed: In vitro protein digestibility, amino acid profile, and some functional properties.

This work evaluated the impacts of pH and sodium chloride (NaCl) concentration on some functional properties, in vitro protein digestibility, and amino acid profile of sesame (Sesamum indicum) protein isolate (SPI) produced using simultaneous recovery of protein and oil technique. The emulsion activity index (EAI), foam capacity (FC), and protein solubility varied with pH and ionic ability. Foam capacity rose with an increase in ionic strength. Protein solubility ranged from 8.39% at pH 4 to 55.08% at pH 10. In vitro protein digestibility of the SPI with pepsin–pancreatin enzyme systems was 89.57%. Amino acid profile showed that essential amino acids constituted 39.48%. The amino acids had good scores well above 50%. The results showed that SPI extracted by aqueous technique could be used as food ingredient, particularly as thickener, binder, and ingredient in baked food products.

Preparation and characterization of protein isolate from Yellowfin tuna Thunnus albacares roe by isoelectric solubilization/precipitation process

Isoelectric solubilization/precipitation (ISP) processing allows selective, pH-induced water solubility of proteins with concurrent separation of lipids and removal of materials not intended for human consumption such as bone, scales, skin, etc. Recovered proteins retain functional properties and nutritional value. Four roe protein isolates (RPIs) from yellowfin tuna roe were prepared under different solubilization and precipitation condition (pH 11/4.5, pH 11/5.5, pH 12/4.5 and pH 12/5.5). RPIs contained 2.3–5.0 % moisture, 79.1–87.8 % protein, 5.6–7.4 % lipid and 3.0–3.8 % ash. Protein content of RPI-1 and RPI-2 precipitated at pH 4.5 and 5.5 after alkaline solubilization at pH 11, was higher than those of RPI-3 and RPI-4 after alkaline solubilization at pH 12 (P < 0.05). Lipid content (5.6–7.4 %) of RPIs was lower than that of freeze-dried concentrate (10.6 %). And leucine and lysine of RPIs were the most abundant amino acids (8.8–9.4 and 8.5–8.9 g/100 g protein, respectively). S, Na, P, K as minerals were the major elements in RPIs. SDS-PAGE of RPIs showed bands at 100, 45, 25 and 15 K. Moisture and protein contents of process water as a 2’nd byproduct were 98.9–99.0 and 1.3–1.8 %, respectively. Therefore, yellowfin tuna roe isolate could be a promising source of valuable nutrients for human food and animal feeds.

Preparation and characterization of protein isolate and biodiesel from garden cress seed

Garden cress seeds were analyzed for proximate composition and mineral content. The protein isolate (PI) was evaluated for chemical composition, mineral content, amino acid composition, biological values and some functional properties. The seed oil was evaluated for fatty acid profile; tocopherols and some of physicochemical properties were studied. Seeds were found to contain 29.11% oil and 25.12% protein. Phosphorus, magnesium and calcium constituted the major minerals of the seeds. The protein efficiency ratio (PER) of PI was 2.37. PI was found to possess relatively high values of water and fat absorption capacity, emulsification capacity and foam capacity. The fatty acid profile showed that linolenic acid (41.17%) and oleic acid (26.42%) were the major unsaturated fatty acids, whereas palmitic acid was the major saturated acid. Total tocopherol content of garden cress oil was 150.46 mg/100 g oil. The physicochemical characteristics of oil and biodiesel meet the norm specifications.

Characterization of protein isolates from different Indian chickpea ( Cicer arietinum L.) cultivars

Protein isolates prepared by alkaline solubilization followed by isoelectric precipitation and freeze drying from desi (PBG-1, PDG-4, PDG-3, GL-769, and GPF-2) and kabuli (L-550) chickpea cultivars were evaluated for functional (water and oil absorption capacities, least gelation concentration, foaming capacity and stability) and thermal properties. Significant difference ( P ⩽ 0.05) in properties of kabuli and desi chickpea protein isolates was observed. Kabuli chickpea protein isolate showed significantly ( P ⩽ 0.05) higher ash (1.14%), protein (94.4%), L ∗, Δ E value, oil absorption capacity (OAC) and lower water absorption capacity (WAC) than their corresponding desi chickpea protein isolates. The solubility-pH profile of different protein isolates showed minimum solubility in the pH between 4.0 and 5.0 and two regions of maximum solubility at pH 2.5 and 7.0. Foaming capacity of all protein isolates increased with the increase in concentration. Kabuli chickpea protein isolate showed the highest foam stability (94.7%) after 120 min of storage. The thermal properties of protein isolates from different chickpea cultivars were studied by differential scanning calorimetry (DSC). Protein isolates from both the chickpea types differed significantly ( P ⩽ 0.05) in peak denaturation temperature ( T d) and heat of transition (Δ H). Kabuli type protein isolate exhibited lower T d and Δ H value as compared to those from desi types. The interrelationships between characteristics of protein isolates showed a significant ( P ⩽ 0.05) negative correlation of T d with protein content and OAC. It was also observed that cultivars with high fat content had high Δ H and lower WAC.

Production, characterization and application of protein isolates from shark. Part 3. Characterization of protein isolates.

The functional and nutritional characterization of two isolates elaborated through cleaning-extraction processes, as well as that of a third isolate obtained by means of a chemical modification (alkaline heat treatment) from one of the former, was carried out. The first two isolates exhibit in general similar properties, are nutritionally comparable with casein and show a fairly high water absorption, having a potentially great value for instance in bakery and meat products and pastes. The modified isolate is essentially different from the isolate used as raw material in many of the characterized parameters, having a high nitrogen solubility index (NSI) by pH 3.5 and 7.0 and thus offering its possible use in such food systems as soft drinks where a high solubility is desired.