ACE-I inhibitory peptide fractions from enzymatic hydrolysates of velvet bean (<i>Mucuna pruriens</i>)

The hydrolysis of velvet bean (Mucuna pruriens) protein in the presence of Alcalase?-Flavourzyme? and Pepsin-Pancreatin was investigated. The results showed that Alcalase?-Flavourzyme? (29.08%) sequential system catalyzed the hydrolysis most efficiently that Pepsin-Pancreatin (24.78%). In addition, the higher ACE-I inhibitory activity was achieved with the sequential system Alcalase?-Flavourzyme? (33.13%). Furthermore, the concentration of peptides employing an ultrafiltration (UF) system or their purification by gel filtration chromatography showed that the oligomeric peptides with lower molecular weight registered the highest ACE-I inhibitory activity. It has been demonstrated that Mucuna pruriens protein hydrolysates could serve as a source of peptides with ACE inhibitory activity and this activity can be attributed mainly to the mixture of short peptides in the hydrolysate.

Lima Bean(Phaseolus lunatus)Protein Hydrolysates with ACE-I Inhibitory Activity

Several protein sources can be used to produce bioactive peptides with angiotensin I-converting enzyme (ACE) inhibittory activity. Protein concentrates from ungerminated and germinated lima bean Phaseolus lunatus seed flours were hydrolyzed with Alcalase 2.4 L or pepsin-pancreatin sequential hydrolysis, and ACE inhibitory activity measured in the different hydrolysis treatments. Protein hydrolysate production was analyzed with a 23 factorial design with four replicates of the central treatment. Evaluated factors were protein concentrate source (ungerminated seeds, PC1;germinated seeds, PC2), enzyme/substrate ratio E/S (1/50 or 1/10) and hydrolysis time (0.5 or 2.0 h for Alcalase;1 or 3 h for pepsin-pancreatin). Degree of hydrolysis (DH) was high for the Alcalase hydrolysates (24.12% 58.94%), but the pepsin-pancreatin hydrolysates exhibited the highest ACE inhibitory activity (IC50 = 0.250 0.692 mg/mL). Under the tested conditions, the hydrolysates with the highest ACE inhibitory activity were produced with sequential pepsin-pancreatin using either PC1 at 1 h hydrolysis time and a 1/10 E/S ratio or PC2 at 1 h hydrolysis time and a 1/50 E/S ratio. Lima bean protein hydrolysates prepared with Alcalase or pepsin-pancreatin are a potential ingredient in the production of physiologically functional foods with antihypertensive activity.

Rapid HPLC Method for Determination of Rebaudioside D in Leaves of Stevia rebaudiana Bertoni Grown in the Southeast of Mexico

Stevia leaves contain glycosides on which biological activity and sweetening capacity has been reported. Besides the main glycosides—stevioside and rebaudioside A—there are minor glycosides that may contribute to the activity and thus it is important to quantify them. Rebaudioside D is one of the minor glycoside present in S. rebaudiana leaves and there are no reports of a validated method to quantify it. Therefore a simple and sensitive high performance liquid chromatography (HPLC) method was validated for the determination of rebaudioside D in leaves of Stevia rebaudiana B. grown in the southeast of México. HPLC method was performed using a C18 column (250 mm × 4.6 mm, 5 μm) and UV detector set at 210 nm. The mobile phase consisted of 32:68 (v/v) mixture of acetonitrile and sodium phosphate buffer (10 mmol/L, pH 2.6), set to a flow rate of 1.0 ml/min. The calculated parameters were: sensitivity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. The retention time of rebaudioside D was found to be 3.47 min ± 0.04 (S.D.). The calibration curves were linear over the working range (25 - 150 μg/ml), with correlation coefficient ≥0.99 and determination coefficient ≥0.98. The calculated limit of detection (LOD) was 8.53 μg/ml, while the limit of quantitation (LOQ) was 25.85 μg/ml. The percent recoveries of fortified samples were 100% ± 10% and precision relative standard deviation was ≤2.79%. The criteria of validation showed accuracy, linearity, and precision;therefore the method is suitable for quantitative analysis of rebaudioside D in Stevia rebaudiana leaves. Rebaudioside D content (g/100g) in Morita II and Criolla varieties grown in the southeast of Mexico were 0.43 and 0.46, respectively with no significant differences (p > 0.05) between them.

Chemical and Functional Properties of Hard-to-Cook Bean (<i>Phaseolus vulgaris</i>) Protein Concentrate

The objective of this research was to evaluate the chemical and functional properties of hard-to-cook (HTC) bean (Phaseolus vulgaris) protein concentrate to determine their potential practical applications. The respective protein concentrate was obtained from the flour using isoelectric precipitation and the protein content was 73.03%. Proximate composition and in vitro digestibility were measured to evaluate the chemical properties, and nitrogen solubility, emulsifying capacity, emulsion stability, foaming capacity, foam stability and viscosity were measured to evaluate its functional properties. The proximate composition of the HTC bean (P. vulgaris) flour and protein concentrate registered values of moisture, ash, protein, fat, fiber and NFE of 8.92, 4.52, 21.71%, 4.41%, 4.11% and 65.25% for flour and of 2.68%, 2.54%, 73.03%, 2.77%, 1.31% and 20.35% for protein concentrate. The in vitro digestibility was of 76.7%. The hard-to-cook bean protein concentrate exhibited good functional properties suggesting its use as additive. This concentrate registered solubility values that are ranging from 2.5% to 71.81%. The emulsifying (EC) and foaming capacity (FC) registered values of 89% - 97% and of 7% - 53% at different pH levels, respectively as well as an emulsion (ES) and foaming stability (FS) pH- and time-dependent. The HTC bean (P. vulgaris) protein concentrate registered a viscosity profile dependent of shear rate. The results suggest that HTC bean (P. vulgaris) protein concentrate is a valuable food ingredient or additive.

Physicochemical and Functional Properties of Dehydrated Japanese Quail (<i>Coturnix japonica</i>) Egg White

Physicochemical, functional and digestibility analyses were done of dehydrated quail egg white to determine its possible practical applications. Quail egg white was dehydrated by air convection using one of two temperatures and times: M1 (65℃, 3.5 h), M2 (65℃, 5.0 h), M3 (70℃, 3.5 h) and M4 (70℃, 5.0 h). Lyophilized quail egg white was used as a standard. All four air-dried treatments had good protein levels (92.56% to 93.96%), with electrophoresis showing the predominant proteins to be lysozyme, ovalbumin and ovotransferin. Denaturation temperatures ranged from 81.16℃ to 83.85℃ and denaturation enthalpy values from 5.51 to 9.08 J/g. Treatments M1-4 had lower water-holding (0.90 - 2.95 g/g) and oil-holding (0.92 - 1.01 g/g) capacities than the lyophilized treatment (4.5 g/g, 1.95 g/g, respectively). Foaming capacity was pH-dependent in all five treatments, with the lowest values at alkaline pH and the highest (153% to 222%) at acid pH (pH 2). Foam stability was lowest at acid pH and highest at alkaline pH. Emulsifying activity in the air-dried treatments was highest at pH 8 (41% - 46%). Emulsion stability was pH-dependent and highest in M3 between pH 2 and 4 (96.16% to 95.74%, respectively). In the air-dried treatments, in vitro protein digestibility was as high as 83.02% (M3).

Fiber Residues from <i>Canavalia ensiformis</i>L. Seeds with Potential Use in Food Industry

The objective of this research was to determine the physicochemical characteristics of fiber residues from Jack bean (Canavalia ensiformis L.) obtained by two technological processes. The proximal composition of the fiber residues from Canavalia ensiformis registered values of moisture, ash, protein, fat, fiber and nitrogen-free extract (NFE) of 7.14%, 3.17%, 9.14%, 1.34%, ?23.84% and 62.51% for residue A and 4.74%, 2.68%, 7.73%, 1.39%, 23.76% and 64.44% for residue B. Total dietary fiber (TDF) contents in the fiber residues were 47.06 (Residue A) and 54.96 (Residue B) g/100g sample, with most of this content represented by insoluble dietary fiber (IDF) 45.46 g/100g sample in Residue A and 52.75 g/100g of sample in Residue B. The remainder was constituted by soluble dietary fiber (SDF). The neutral detergent fiber (NDF) content was slightly higher in residue B (41.8 g/100g sample). Acid detergent fiber (ADF) that includes principally cellulose, lignin and cutin, and acid detergent lignin (ADL) that include lignin and cutin were higher in residue B (32.5 g/100g sample) and similar for both residues (1.0 (A) and 1.2 (B) g/100g sample), respectively. Resistant starch (RS) was higher in residue B (0.607%) than in residue A (0.358%). No statistical difference (p > 0.05) was registered in the tannins content of both residues. However, the phytates content was higher in the fiber residue obtained by the fists technological process (A residue). In vitro digestibility was higher in residue A (85.81%) than that in B residue (81.51%). The results of the present study suggest the potential use of C. ensiformis fiber residues as a functional ingredient in foods, especially in the development of reduced calorie food and dietary fiber enriched foods.

Physicochemical and Functional Characterization of <i>Mucuna pruries</i>Depigmented Starch for Potential Industrial Applications

Starch is a very important biopolymer in the food industry. The velvet bean (M. pruriens) is an excellent potential starch source containing approximately 520 g starch per kg. The objective of this study was to evaluate the physicochemical and functional properties of velvet bean depigmented starch. The starch granules appear oval and spherical shaped. The colour registered L*, a*, b* values of 44.9, 0.324 and 0.341 respectively. The chemical composition registered values of moisture, ash, fat, protein, fibre and NFE of 110.5, 5.8, 5.7, 0.0, 34 and 954.5 g/kg respectively, as well as amylose levels of 215.3 g/kg. Gelatinization onset (To), peak (Tp) and final (Tf) temperatures were of 74.23°C, 80.57°C and 86.39°C. The solubility (3.1% - 16.2%), swelling power (SP) (2.86% - 16.17%) and water absorption capacity (WAC) (2.67 - 15.95 g water/g starch) were directly correlated to temperature (60°C - 90°C). The enthalpy values (4.10 - 13.47 j/g) were directly correlated to the time (1 - 21 days). The retrogradation increased as time increased. The viscosity of M. pruriens depigmented starch decreased slightly during the heating stages and then increased during cooling and the refrigeration and freezing stability registered syneresis ranges from 17.65 to 23.18 mL/50mL and from 16.4 to 22.6 mL/50mL respectively, indicating that the depigmented starch was unstable in heating-cooling processes.

Physicochemical characterization of chia (<i>Salvia hispanica</i>) seed oil from Yucatán, México

A physicochemical characterization of oil from chia seeds was carried out. Proximate composition analysis showed that fat and fiber were the principal components in the raw chia flour. Physical characterization showed that chia oil has a relative density from 0.9241, a refraction index of 1.4761 and a color with more yellow than red units. Chemical characterization showed that chia oil registered an acidity index of 2.053 mg KOH/g oil, a saponification index of 222.66 mg KOH/g oil, a content of unsaponifiable matter of 0.087%, an Iodine index of 193.45 g I/100 g oil and a peroxide index of 17.5 meq O2/kg oil. Chia oil showed a higher content of α and β linolenic and palmitic acids. Chia oil is the vegetable source with the highest content of essential fatty acids.

Determination of Rebaudioside A and Stevioside in Leaves of S.rebaudiana Bertoni Grown in Mexico by a Validated HPLC Method

Stevia rebaudiana is a plant with high sweetening capacity due to its content of glycosides, mainly stevioside and rebaudioside A. Several techniques have been used to determine the concentrations of glycosides in Stevia, although an HPLC method is recommended by the FAO/WHO-JECFA. Varieties of Stevia have been recently grown in Mexico, with no previous report of glycosides by a validated method. The aim of this study was to validate an isocratic HPLC method for content determination of main glycosides in the leaves of Stevia cultivated in Mexico. HPLC method was performed using a C18 column (250 mm × 4.6 mm, 5 μm) and UV detector set at 210 nm. The mobile phase consisted of 32:68 (v/v) mixture of acetonitrile and sodium-phosphate buffer (10 mmol/L, pH 2.6), set to a flow rate of 1.0 mL/min. Rebaudioside A and stevioside were determined in two Stevia varieties: Morita II and Criolla, and also validation parameters were calculated. Rebaudioside A content (g/100g) in Morita II was 15.15 ± 0.02 while stevioside was 3.97 ± 0.003;in the case of Criolla they were 4.03 ± 0.01 and 8.80 ± 0.14, respectively (p < 0.001). The recoveries of fortified samples were 100% ± 10% and precision RSD was ≤6.27%. The criteria of validation showed accuracy, linearity (≥0.99), and precision;therefore, the determination of glycosides was performed with reliability.

Comparison of Chemical and Functional Properties of Stevia rebaudiana(Bertoni)Varieties Cultivated in Mexican Southeast

The leaf powders from two varieties of Stevia rebaudiana (Bertoni) cultivated in Yucatan, Mexico were analyzed for their proximate composition, dietary fiber composition and functional properties. The leaf powders were a good source of carbohydrates (64.06%-67.98%), protein (12.11%-15.05%), and crudefiber (5.92%-9.52%). Total dietary fiber content in the S. rebaudiana leaf powders were 28.61 (Morita II) and 29.12 (Criolla) g/100g sample, with most of this content represented by insoluble dietary fiber 87.79% (Morita II) and 70.02% (Criolla). Neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) were higher in Criolla (19.29%, 17.77%, 8.98%) than Morita II variety (18.11%, 14.16%, 2.28%). Hemicellulose and cellulose were higher in Morita II (3.96%, 11.78%) than criolla variety (1.51%, 8.79%). Functional properties of leaf powder from Morita II and Criolla were, water-holding capacity (2.87-4.07 g/g sample), oil-holding capacity (6.49-6.79 g/g sample), water-absorption capacity (3.41-3.44 g/g sample), water-adsorption capacity (0.25-0.28 g/g sample), and organic molecule absorption capacity (1.13-1.81 g/g sample). These suggest that S. rebaudiana (Bertoni) leaf powders may be used as dietary supplement or as food additive.