Maira Segura-Campos

Bioavailability of Bioactive Peptides

Peptides from various dietary sources have been shown to have clearly positive effects on health by functioning as antihypertensives, antioxidants, anticarcinogens, antimicrobials, and anticariogenics, among others. Implementation of a peptides potential biological effect depends largely on its ability to remain intact until reaching the target organ. Research in humans has shown that peptides of different sizes can pass through the intestinal epithelium. To exercise their effects, peptides need to preserve their bioactivity during the digestive process, requiring determination of the most appropriate structures or peptide modification by chemical methods (lipidation) or physical methods (microencapsulation).

Chemical and Functional Properties of Chia Seed (Salvia hispanica L.) Gum

Chia (Salvia hispanica L.) constitutes a potential alternative raw material and ingredient in food industry applications due to its dietary fiber content. Gum can be extracted from its dietary fiber fractions for use as an additive to control viscosity, stability, texture, and consistency in food systems. The gum extracted from chia seeds was characterized to determine their quality and potential as functional food additives. The extracted chia gum contained 26.2% fat and a portion was submitted to fat extraction, producing two fractions: gum with fat (FCG) and gum partly defatted (PDCG). Proximal composition and physicochemical characterization showed these fractions to be different (P < 0.05). The PDCG had higher protein, ash, and carbohydrates content than the FCG, in addition to higher water-holding (110.5 g water/g fiber) and water-binding capacities (0.84 g water/g fiber). The FCG had greater oil-holding capacity (25.7 g oil/g fiber) and water absorption capacity (44 g water/g fiber). In dispersion trials, the gums exhibited a non-Newtonian fluid behavior, specifically shear thinning or pseudoplastic type. PDCG had more viscosity than FCG. Chia seed is an excellent natural source of gum with good physicochemical and functional qualities, and is very promising for use in food industry.

Defatted Jatropha curcas flour and protein isolate as materials for protein hydrolysates with biological activity.

Jatropha curcas L. protein hydrolysates were produced by treatment of a non-toxic genotype with Alcalase as well as the digestive enzymes pepsin and pancreatin. The J. curcas protein hydrolysate produced with the pepsin-pancreatin system from protein isolate had the highest TEAC value and was shown to undergo single-electron transfer reactions in the ABTS(+) reduction assay, demonstrating its antioxidant capacity. Testing of antimicrobial activity in the J. curcas protein hydrolysates against seven bacterial pathogens showed no growth inhibitory effect in Gram-negative and Gram-positive bacteria. More ACE-I inhibitory active peptides were produced in the Alcalase hydrolysates obtained from J. curcas protein isolate. The protein hydrolysate obtained with Alcalase from defatted J. curcas flour as well as from the protein isolate showed the highest inhibitory effect of ADP-induced aggregation of human platelets in platelet-rich plasma. It is expected that the information collated will facilitate new applications of proteins present in Jatropha plant.

Effect of Enzymatic Hydrolysis on Solubility, Hydrophobicity, and In Vivo Digestibility in Cowpea (Vigna unguiculata)

Vigna unguiculata protein concentrate was enzymatically hydrolyzed with Alcalase® and Flavourzyme® and the resulting hydrolysates, with the highest respective degrees of hydrolysis, functional, and nutritional properties, were evaluated. Hydrolysis was conducted for 5, 10, 15, and 60 min. Degree of hydrolysis values increased from 10.56 and 3.26%, respectively, at 5 min to 23.61 and 7.27%, respectively, at 60 min. The Flavourzyme® hydrolysate exhibited higher solubility and surface hydrophobicity than the Alcalase® hydrolysate. A large number of low molecular weight bands in the Alcalase® hydrolysate suggested that hydrolysis was extensive (DH = 23.6%). Both hydrolysates exhibited digestibility and intestinal absorption levels comparable to a casein control.

ACE-I inhibitory properties of hydrolysates from germinated and ungerminated Phaseolus lunatus proteins

Phaseolus lunatus protein concentrates and the proteases Alcalase(R) and Pepsin-Pancreatin were used for the production of protein hydrolysates that inhibit angiotensin-I converting enzyme (ACE). Protein concentrate obtained from germinated and ungerminated seeds flour was hydrolyzed with Alcalase(R) at enzyme/substrate ratio (E/S) 1/10 and during 0.5 and 2.0 h, respectively. On the other hand, protein concentrate obtained from ungerminated (E/S: 1/10) and germinated (E/S: 1/50) seeds flour was sequentially hydrolyzed with Pepsin-Pancreatin during 1.0 and 3.0 h, respectively. Peptide fractions with ACE inhibitory activity in a range of 0.9 to 3.8 µg/mL were obtained by G-50 gel filtration chromatography and high- performance liquid chromatography C18 reverse phase chromatography. The observed amino acid composition suggests a substantial contribution of hydrophobic residues to the peptides’ inhibitory potency, which potentially acts via blocking of angiotensin II production. These results show that P. lunatus seed proteins are a potential source of ACE inhibitory peptides when hydrolyzed with Alcalase(R) and Pepsin-Pancreatin.

Whole and crushed nutlets of chia (Salvia hispanica) from Mexico as a source of functional gums

The objective of this study was to characterize the chemical and functional properties of Mexican chia (Salvia hispanica) gums extracted from defatted whole and crushed nutlets using the Soxhlet and SFE-CO2 methods. Chia gums have interesting chemical and functional properties for the food industry. The oil and gum yields were in the range of 1.98-16.42% and 5.81-12.60%, respectively. The defatting procedure did not affect significantly the oil and gum extraction; the nutlet type (whole or crushed) was the only parameter influencing the yield. The proximate composition and the protein and fiber contents of chia gum were evaluated. Low contents of protein and fiber and high NFE levels were found in whole nutlet gums. The functional properties of chia gum extracted from whole and crushed nutlets with the Soxhlet and SFE-COs methods showed the following ranges of water absorption capacity of 62.64 to 143.66 g/g, water adsorption capacity of 0.69 to 1.35 g/g, and water and oil holding capacity of 100 to 149.28 g/g and19.5 to 40.4 g/g, respectively. The rheological behavior exhibited by the gums was pseudoplastic or shear thinning. From a functional perspective, chia gum is an important food component due its emulsifier and stabilizer potentials.

Biological activity of Stevia rebaudiana Bertoni and their relationship to health

ABSTRACT The leaves of Stevia rebaudiana Bertoni has nutrients and phytochemicals, which make it an adequate source for the extraction and production of functional food ingredients. Preclinical and clinical studies suggest therapeutic and pharmacological applications for stevia and their extracts because they are not toxic and exhibit several biological activities. This review presents the biological activity of Stevia rebaudiana Bertoni and their relationship to antidiabetic, anticariogenic, antioxidant, hypotensive, antihypertensive, antimicrobial, anti-inflammatory and antitumor activities. Consumption and adverse effects were also reviewed.

Studies on drying characteristic, nutritional composition, and antioxidant properties of Stevia rebaudiana (Bertoni) leaves

Abstract Drying characteristics of Stevia rebaudiana (Bertoni) leaves using radiation drying, convection drying, sun drying, and shade drying treatments were investigated in a convective type. Results for all treatments indicated that drying took place in the falling rate period. The chroma of the dried samples ranged between 29.66 and 23.85. Convection and shade drying samples were found better in colour and had the highest content of total pigments. The proximate and fibre composition were affected by the drying treatments. Extracts obtained from convection drying and shade drying leaves exhibited higher values of Trolox equivalent antioxidant capacities 416.89-423.64 mM mg−1 and ferric reducing power 85.19-87.97%. These extracts also showed ion chelating capacity 59.05-60.21% for Cu+2 and 55.05-59.11% for Fe+2. The results indicate that it is possible to select the drying treatment to obtain the best nutritional and biological properties. Convection drying and shade drying were the least aggressive treatments and leaf powders obtained by these drying methods could be used as sources of nutrients, fibre, and antioxidant compounds.

EVALUACIÓN DE LA INOCUIDAD DE STEVIA REBAUDIANA BERTONI CULTIVADA EN EL SURESTE DE MÉXICO COMO EDULCORANTE DE ALIMENTOS

Stevia rebaudiana leaves and their glycosides have been recently and significantly used so important as sweeteners. However, it has been reported an antihyperglycemic effect of the extract and a glycoside. The aim of this study was to quantify S. rebaudiana glycosides, assess cytotoxicity of the extract and its acute and chronic effect on blood glucose in animal models and in human. The glycosides of the Morita II and Criolla extract were quantified by HPLC, using a C18 column (250 mm x 4.6 mm and particle size of 5 uM) with UV detection at 210 nm, mobile phase of acetonitrile/sodium phosphate buffer 10 mmol/L, pH 2.6 (32:68 v/v). Cytotoxicity study was performed in Vero cells, whereas an intraperitoneal glucose tolerance test (IPGTT) and a chronic consumption assay (4 weeks) were executed in an animal model of diabetes; finally the glycemic index (G.I.) was determined in healthy individuals. The glycoside content is higher in the Morita variety II although both had a CC50 >300 g/mL. The areas under the curve of the IPGTT and fasting glucose of the animals were not significantly different (p> 0.05) and the I.G. extract was 11.11 %, which classifies the extract as low I.G. The extract of S. rebaudiana Morita II has a low glycemic index and, in the doses tested, is not cytotoxic nor has acute or chronic effect on blood sugar, which makes it a safe sweetener.

Antioxidant activity of Vigna unguiculata L. walp and hard-to-cook Phaseolus vulgaris L. protein hydrolysates

Recent research, using model systems, has shown that enzymatic hydrolysis of food proteins can make them act as direct scavengers of diverse free radicals. This study aimed at the characterization of protein hydrolysates with antioxidant properties from Vigna unguiculata L. walp and hard-to-cook Phaseolus vulgaris L. protein concentrates. The maximum values obtained for all the assays were 15.1 mM/mg of protein for Trolox-equivalent-antioxidative capacity, 98.2% for percentage of 2,2-diphenyl-1-picrylhydrazyl (DPPH) discoloration, 70.1% and 71.4% for iron and copper chelating activities, respectively. The reducing power of hydrolysates was higher than butylated hydroxytoluene (BHT) (control). The antioxidant activity of the hydrolysates may be a result of enzymatic hydrolysis generating peptides that exhibit this type of activity. The hydrolysates showed an increase of amino acids that have been associated with the biological activity of peptides with antioxidant activity, such as hydrophobic residues: Ala, Phe and Ile; hydrophilic: Lys and neutral: Ser and Gly.