Raúl Sánchez-Vioque

Protein isolates from chickpea (Cicer arietinum L.): chemical composition, functional properties and protein characterization

Two types of protein isolates were prepared from ground chickpea seeds by alkaline extraction, with (Isolate-B) and without (Isolate-A) sodium sulphite, and acid precipitation of the proteins at the isoelectric point (pI 4.3). The percentage of protein recovered from chickpea flour in the preparation of Isolates-A and B were 65.9 and 62.1%, respectively. Chemical composition, main functional properties and protein composition of chickpea flour and protein isolates were determined. Isolates-A and B contained 78 and 88.1% of protein, respectively, and had a balanced content of essential amino acids, with respect to the FAO pattern. The in vitro protein digestibility ranged between 95.6 and 96.1%. Isolate-A showed a partial dissociation of the 11S protein because of the high pH used for the protein extraction, and this probably explains the differences observed in the functional characteristics of both isolates.

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

Abstract 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.

Effect of cooking on protein quality of chickpea (Cicer arietinum) seeds

Amino acid composition and in vitro protein digestibility of cooked chickpea were determined and compared to raw chickpea seeds. Heat treatment produced a decrease of methionine, cysteine, lysine, arginine, tyrosine and leucine, the highest reductions being in cysteine (15%) and lysine (13.2%). Protein content declined by 3.4% and in vitro protein digestibility improved significantly from 71.8 to 83.5% after cooking. The decrease of lysine was higher in the cooked chickpea seeds than in the heated protein fractions, globulins and albumins. The structural modification in globulins during heat treatment seems to be the reason for the increase in protein digestibility, although the activity of proteolytic inhibitors in the albumin fraction was not reduced. Results suggest that appropriate heat treatment may improve the bioavailability of chickpea proteins.

Factors affecting the in vitro protein digestibility of chickpea albumins

In vitro protein digestibility (IVPD) of chickpea albumins and its possible relationship to their structure and the presence of trypsin inhibitor activity (TIA) have been studied. Trypsin digestion of the albumin fraction under non-reducing conditions was incomplete, while the reduction of inter- and intramolecular disulphide bonds caused an improvement in the accessibility of sites susceptible to trypsin digestion. Trypsin inhibitor activity in the chickpea albumin fraction was dependent upon both temperature and heating time. Although heating the albumin fraction at 100 °C for 30 min reduced the TIA by more than 50% with respect to the initial activity, an important TIA rate was attributable to heat-resistant trypsin inhibitor. The TIA decrease was not related to an increase in the rate of IVPD. However, we observed a significant (P ≤ 0.05) increment in IVPD in the presence of β-ME, confirming the essential role of disulphide bonds in stabilising the protein structure of the albumin fraction. © 2000 Society of Chemical Industry

Chemical composition of extracted dried olive pomaces containing two and three phases

Abstract The chemical composition of extracted dried olive pomaces, obtained from extraction of systems containing two and three phases, was similar. The main component was fibre, with values above 70% in both systems. Nitrogen values and extractability was low for both systems, although in vitro protein digestibility was high (75–80%). Amino acid composition was balanced except for lysine. The isoelectric point was low, centred around pH 2.0. Soluble sugars and organic acids contents were similar as well as fatty acid composition of the extracted oil from olive pomace. Therefore, an oil extraction of a system of two phases is advisable as environmental problems could be reduced with the elimination of vegetation water, and similar applications could be carried out with both types after drying.

Effect of processing on water absorption and softening kinetics in chickpea (Cicer arietinum L) seeds

The processing effect on the physical properties of chickpea seeds (kabuli type cv Athenas) is reported. Soaking of chickpea seeds in different solutions (distilled water, 0·5% NaHCO3 and 0·5% CaCl2) is characterised by a rapid water absorption followed by a decrease in the hydration rate to saturation point. An improvement in chickpea softening rate and water absorption during cooking, with previous 12 h soaking in 0·5% NaHCO3, was observed. The presence of Ca2+ ions delayed the softening process in chickpea seeds. Physicochemical changes associated to the soaking and cooking process necessary for reducing cooking time are discussed. The texturometer method was estimated as a suitable objective method for the evaluation of the cooking degree in chickpea seeds.

Polar lipids of defatted chickpea (Cicer arietinum L.) flour and protein isolates

Polar lipid composition of defatted chickpea flour and protein isolates was studied. The main compounds were phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. Other compounds, in lower amounts, were sterol glucosides, esterified sterol glucosides and digalactosyldiglycerides. Palmitic, oleic and linoleic acid were the main fatty acids in polar lipids. A reduction in the content of phosphatidylinositol and sterol glucosides in the protein isolates with respect to the defatted flour was observed, indicating that these compounds are more sensitive to the chemical treatment of the protein isolates. However, unsaturated fatty acids and unsaturated sterols content decreased in the protein isolates probably undergoing oxidative degradation.

Study of neutral lipids ofLupinus mutabilis meal and isolates

Two types of protein isolates have been obtained from defattedLupinus mutabilis meal. The isolates, MA and MB, were obtained by alkaline extraction with 0.2% NaOH and 0.25% sodium bisulfite, respectively, followed by precipitation at the isoelectric point (pH 4.8). Total associated lipids were extracted with 86% ethanol. Neutral lipids were separated in a Florisil column. The lipids in the isolates were similar to those found in the original meal. The following types of compounds were separated, identified, and quantitated: hydrocarbons, waxes, methyl esters, triacylglycerols, free fatty acids, diacylglycerols, and free sterols.

Biocidal potential and chemical composition of industrial essential oils from Hyssopus officinalis, Lavandula x intermedia var. super and Santolina chamaecyparissus

This work presents the biocidal (insecticidal, ixodicidal, nematicidal, and phytotoxic) effects and chemical compositions of three essential oils obtained from the industrial steam distillation (IEOs) of hyssop (Hyssopus officinalis L.), lavandin (Lavandula × intermedia or L. × hybrida var. Super), and cotton lavender (Santolina chamaecyparissus L.). Their chemical composition analyzed by gas chromatography coupled to mass spectrometry showed 1,8‐cineole (53%) and β‐pinene (16%) as the major components of H. officinalis, linalyl acetate (38%) and linalool (29%) of L. × intermedia; and 1,8‐cineole (10%) and 8‐methylene‐3‐oxatricyclo[5.2.0.02,4]nonane (8%) in S. chamaecyparissus. The biocidal tests showed that L. × intermedia IEO was the most active against the insect Spodoptera littoralis and toxic to the tick Hyalomma lusitanicum, IEO of H. officinalis was strongly active against S. littoralis, and finally, S. chamaecyparissus IEO was a strong antifeedant against the aphid Rhopalosiphum padi, toxic to H. lusitanicum and with moderate effects against Leptinotarsa decemlineata, S. littoralis, and Lolium perenne.

Alcalase rapeseed inhibitors: purification and partial characterization.

Extensive rapeseed protein hydrolysate obtained sequentially with Alcalase and Flavourzyme showed inhibitory activity towards Alcalase. Inhibitory activity decreased as the hydrolytic process progressed probably by heat denaturation and/or partial protease degradation. Alcalase rapeseed inhibitors were purified by gel filtration and subsequent ion exchange chromatography. They are composed of peptides of 8.4 and 6.1 kDa linked by interchain disulphide bonds, as observed by reducing SDS-PAGE, with a native molecular weight of 18 kDa. Aminoacid composition of the inhibitors was characterized by the high proportion of methionine (4.2%) and cysteine (4.6%). Alcalase inhibitors were partially resistant to heat treatment; after heating at 70 °C for 45 minutes more than 50% of the original inhibitory activity remained in the purified protein but after heating at 90 °C for 5 minutes, inhibitory activity decreased very fast to a basal level. The possible relation of these protease inhibitors with the 2S albumin storage proteins is discussed.