Chickpea Protein Isolates Research Articles

PHYSICOCHEMICAL AND PROCESSING FUNCTIONAL PROPERTIES OF PROTEINS FROM TWO CHINESE CHICKPEA (CICER ARIETINUML.) CULTIVARS

The physicochemical and functional properties of protein isolates from two Chinese chickpea cultivars were investigated and compared with those of SPI. GCPI has the lightest, reddest, most yellow and highest chroma. SHF and Ho of three protein isolates were significantly different (P < 0.05). Significant differences (P < 0.05) in EAI, FC, FS and LGC were observed between the two chickpea protein isolates, whose most functional properties were inferior to those of SPI. Most textural properties of heated gels from two chickpea protein isolates were similar and were also inferior to those of the SPI heated gel. PRACTICAL APPLICATIONS Chickpea is the third most widely grown grain legume crop in the world after bean and soybean. In the present study, we examined the physicochemical properties (chemical composition, color characteristics, SHF content and Ho) and functional properties (nitrogen solubility, emulsifying properties, WHC and OHC, FC and FS, and gelation properties) of protein isolates derived from Desi and Kabuli chickpea cultivars grown in Xinjiang Autonomous Region in China, and compared them with those of SPI. This study would be useful in the comprehensive understanding of the characteristics of chickpea protein and its use as a potential additive for food and dietary items.

Chickpea protein isolates obtained by wet extraction as emulsifying agents

Wet extraction of protein from defatted chickpea (variety Thiva (T), Greece) flour, at alkaline or slightly acidic pH, followed by isoelectric precipitation (pI) or ultrafiltration (UF) to recover the protein, was employed to obtain a number of chickpea protein isolates, enriched either in protein constituents belonging to the globulin (TpI, TUF, TUFG) or to the albumin fraction (TUFA). The interfacial activity and film-forming ability of the isolate protein constituents as well as their emulsifying properties were evaluated. The method applied for chickpea protein isolate preparation influenced to an appreciable extent their composition, adsorption behaviour to oil-water interfaces and emulsion formation and stabilization characteristics, especially with respect to oil droplet flocculation and coalescence. The isolates also differed in their ability to stabilize emulsions subjected to thermal processing or following storage under freezing conditions. The results are discussed in terms of compositional and, possibly, structural differences existing between the protein constituents of the chickpea isolates that may influence their functional behaviour in emulsion systems. The method applied for isolate preparation influenced to an appreciable extent the ability of proteins to adsorb to the oil-water interface and stabilize emulsions during long-time ageing or following heat treatment or freezing.

In vivo (rat) and in vitro (Caco-2 cells) absorption of amino acids from legume protein isolates as compared to lactalbumin or casein

The amino acid absorption from legume protein isolates (from chickpeas, CPI; and lupins, LPI) was studied in in vivo and in vitro experiments in comparison to animal proteins (casein and lactalbumin). In the in vivo experiment on rats, the diets were isoenergetic and isonitrogen (per kg diet 15.5 MJ digestible energy and 150 g protein, respectively). At 150 min after feeding, the concentration of free amino acids in arterial and portal blood plasma of rats fed legume proteins was significantly different (p < 0.05) from rats fed animal protein (lactalbumin). In arterial plasma the concentration for Met, Leu, Trp and Lys in rats fed legume proteins was lower than lactalbumin controls and for Val and Cys higher; in portal plasma, the concentration of free Met, Leu, Trp and Lys was lower, and the concentration of Cys was higher in rats fed legume proteins than in rats fed lactalbumin. The cumulative (total mM at 195 min after ingestion) and net absorption (% of ingested amounts) of Met, Leu, Trp and Lys were higher (p < 0.01) for rats fed lactalbumin as compared to those fed legume protein isolates or casein. In the in vitro study (Caco-2 cell monolayers), after 2 h incubation the transport values of all the individual amino acids in CPI and LPI, except for Glu, Val and Ile, were lower (p < 0.01) than for casein or lactalbumin. The results indicate that amino acids from chickpea and lupin protein isolates are absorbed at slower rates than those from animal proteins, which might explain the lower nutritional utilisation of legume storage proteins as compared with lactalbumin or casein.

Subunit, amino acid composition and in vitro digestibility of protein isolates from Chinese kabuli and desi chickpea (Cicer arietinum L.) cultivars

The subunit, amino acid composition and in vitro digestibility of the two protein isolates (GCPI and ZCPI) from one kabuli and one desi chickpea cultivars, grown extensively in Xinjiang Autonomous Region of China, were investigated and compared with those of soy protein isolate (SPI). SDS–PAGE showed that GCPI and ZCPI had almost the same band components under the reduced and unreduced conditions, with only minor difference in relative quantity for some bands, but different from that of SPI. The sulphur-containing amino acids were the first limiting amino acids for all three protein isolates of GCPI (2.11 g/100 g), ZCPI (2.20 g/100 g) and SPI (1.99 g/100 g). Amino acid score of the three protein isolates could reach the FAO/WHO requirement (1990) for the essential amino acids for preschool children. The order of in vitro digestibility was GCPI (87.47%) > ZCPI (80.82%) > SPI (71.04%). Our results indicated that, compared with soybean protein isolate, Chinese kabuli and desi chickpea protein isolates had higher digestibility value, and chickpea protein, especially for kabuli protein, could be utilized as a good source of protein for human nutrition.

Influence of preparation methods on physicochemical and gelation properties of chickpea protein isolates

Two protein isolates were prepared from defatted chickpea seed flour by applying alkaline extraction followed by isoelectric precipitation or ultrafiltration (TpI and TUF, respectively), while another one (TF) was obtained by a combination of protein extraction at a mildly acidic environment and ultrafiltration processes. The isolates differed in composition, with the TpI and TF containing mainly the chickpea globulins and the albumins, respectively, whereas the TUF isolate consisted of both types of proteins with the globulin fraction dominating over the albumins. The differences in protein composition between the isolates as well as the impact of extraction conditions were reflected in their protein solubility, surface hydrophobicity, sulfhydryl group content, thermal properties and the onset of gelation during heating. On the other hand, the protein isolate gelling behavior depended mainly on the method applied for their preparation rather than the protein composition, with the isolates obtained by ultrafiltration exhibiting lower gelling concentrations and gel networks of higher elasticity at protein contents below 12% (w/v).

Emulsifying properties of chickpea protein isolates: Influence of pH and NaCl

Structure and emulsifying properties of chickpea protein isolates (CPI) as a function of protein concentration, oil volume, pH and ionic strength were studied. The optimum protein concentration 2 g l −1 used to determine the emulsifying properties was obtained. Emulsifying activity index (EAI) increased from 244 to 376 m 2 g −1 with pH from 3.0 to 11.0 except the protein isoelectric point (p I 5.0), where the EAI was 20 m 2 g −1 and emulsion droplet size was the largest. At lower ionic strengths (0.0–0.1 M NaCl, pH 7.0), EAI decreased from 253 to 72.4 m 2 g −1; however, it increased from 72.4 to 231.4 m 2 g −1 at higher ionic strengths (0.1–1.0 M NaCl). A positive relation between EAI and surface hydrophobicity ( S 0) of CPI at various ionic strengths was obtained, while EAI was independent of S 0 under different pH values. α-Helix was the major configuration of CPI at the p I or lower ionic strength.

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.

Gelation properties of chickpea protein isolates

The effects of pH, sodium and calcium chloride on the gelation properties of chickpea protein isolates (CPI) were investigated. The dispersion prepared with deionized water at pH 3.0 behaved as diluted solution, while dispersions at pH 3.0 with 0.1 M NaCl and pH 7.0 with 0.5–1.0 M NaCl behaved as semidiluted solutions. The samples prepared with high ionic strengths (0.5–1.0 M NaCl) at pH 3.0 and with low ionic strengths (0–0.1 M NaCl) at pH 7.0 were more elastic with a gel-like behavior. The samples at pH 3.0 with high ionic strengths and at pH 7.0 with low ionic strengths had the similar gelation kinetics. The effect of calcium chloride on gelation properties of CPI was similar to that of NaCl. The dispersions behaved as gel at pH 3.0, CaCl 2 0.1–0.3 M and pH 7.0, CaCl 2 0.1 M, because they were more elastic than viscous. The sample at pH 7.0 with 0.3 M CaCl 2 behaved as semidiluted solutions. The gel strength at pH 3.0, 0.1 and 0.3 M CaCl 2 was 24 and 26.4 g, respectively. However, the gel strength prepared with 0.1, 0.5 and 1.0 M NaCl was 7.6, 8.4 and 9.3 g, respectively.

Utilisation of chickpea protein isolates for production of peptides with angiotensin I‐converting enzyme (ACE)‐inhibitory activity

AbstractChickpea protein isolates and the protease alcalase were used for the production of protein hydrolysates that inhibit angiotensin I‐converting enzyme (ACE). The highest degree of inhibition was found in a hydrolysate obtained by 30 min of treatment with alcalase. This hydrolysate was used as starting material for the purification of ACE‐inhibitory peptides. After Biogel P2 gel filtration chromatography and HPLC C18 reverse phase chromatography, four peptides with ACE‐inhibitory activity were purified. Two of them were competitive inhibitors of ACE, while the other two were uncompetitive inhibitors. These results show that chickpea proteins are a good source of ACE‐inhibitory peptides when hydrolysed with the protease alcalase.© 2002 Society of Chemical Industry

Protein quality of chickpea ( Cicer arietinum L.) protein hydrolysates

Chickpea protein isolate (CPI) was used as the starting material in the production of chickpea protein hydrolysates (CPHs). To obtain a highly extensive hydrolysate with a degree of hydrolysis higher than 50%, a sequential utilisation of endoprotease (Alcalase) and exoprotease (Flavourzyme) was necessary. Molecular weight patterns of CPHs were determined by gel filtration chromatography. As a result of the enzymatic activity, differences in the chromatographic pattern of CPHs were observed. Although significant ( P⩽0.05) decreases of Phe and Arg were observed after hydrolysis, adequate amounts of essential amino acids in relation to the reference pattern of FAO (FAO/WHO/ONU, 1985. Energy and requirements. Technical report series No. 724. Geneva) were found. In vitro protein digestibility of CPHs (95%) were similar to that of the starting material (CPI), and TIA was not detected in any case. A high increase of solubility in CPHs, with respect to CPI, was observed, one CPH being totally soluble over a wide pH range (2–10) when the enzymes were added sequentially. Due to their high protein quality and solubility, CPHs might be considered as potential ingredients in the food industry.

Production of extensive chickpea (Cicer arietinum L.) protein hydrolysates with reduced antigenic activity.

Chickpea protein isolate was used as starting material for the production of hypoallergenic protein hydrolysates. Western blotting of the protein isolate showed that IgE in sensitized patient sera strongly bound to the basic polypeptidic chains and recognized the acidic ones of 11S globulin. During the hydrolysis process by the individual and/or sequential action of endo- and exoproteases, a high reduction of antigenic activity was observed. Results suggest that the presence of intact or partially hydrolyzed basic polypeptide chains of 11S globulin are responsible for the formation of IgE complexes in protein hydrolysates obtained by exoprotease treatment; however, the digestion of these polypeptide chains by individual action of endoprotease caused a high loss of antigenic activity. The most effective reduction of antigenicity, >90%, was observed in extensive hydrolyzed chickpea proteins obtained by sequential treatment with endo- and exopeptidases. This chickpea protein hydrolysate could be useful for the elaboration of specialized hypoallergenic food products.

Use of plant protein isolates in processed cheese

AbstractPlant protein isolates were evaluated and used to replace skim milk powdered protein in processed cheese blends. The chemical composition of chickpea protein isolate (CPI), peanut protein isolate (PPI) and sesame protein isolates (SPI) were determined. Functional properties of the tested protein isolates were also studied. SPI had minimum emulsion activity index (EAI), while the PPI possessed the highest value. The emulsions formed remained stable after one day, then destroyed at the 3rd day. Water absorption capacity (WAC) of the tested protein isolates varried between 196 to 329 g water/100 g protein. The water‐oil absorption index (WOAI) for CPI, PPI and SPI were 7.6, 0.48 and 0.90, respectively.Changes in chemical composition of plant‐type processed cheeses containing different levels of plant protein isolates (5, 10 and 15%), occurred only in total nitrogen, while the other constituents such as total solids, fat and salt were not affected. Sensory evaluation of the processed cheese revealed that total score gradually decreased with increasing plant‐protein isolate levels up to 15% but still preferable for the consumer. This decrease in the total score regards the flavour but not to the colour or body and texture.