María Eugenia Jaramillo-Flores

Effect of Thermal Treatment on the Antioxidant Activity and Content of Carotenoids and Phenolic Compounds of Cactus Pear Cladodes (Opuntia ficus-indica)

Cactus pears (Opuntia ficus-indica) are draught resistant plants originated in Mexico. Their flattened stem segments, called cladodes, have moisture, protein and fibre contents of 92, 1-2 and 4-6% respectively, and a pectin content in the range of 0.8-3.3% depending on the species. They also contain certain concentration of carotenoids which are of special interest because of their antioxidant activity. This work is aimed to identify and quantify the main carotenoids present in the stems and to evaluate the effect of thermal treatments on the antioxidant activity and concentration of carotenoids and phenolic compounds. The carotenoids -cryptoxanthin, -carotene and lutein were identified in the cladodes, the latter having the highest concentration. Thermal treatments increased the extractability of these pigments and the antioxidant activity was related to the carotenoids concentration. Total phenolic content decreased after the thermal treatments; however this result had little effect on the antioxidant activity. Mucilage present in the stems decreased the extractability of the carotenoids.

Evaluation of Phenylpropanoids in Ten Capsicum annuum L. Varieties and Their Inhibitory Effects on Listeria monocytogenes Murray, Webb and Swann Scott A

Extracts of pepper from ten different varieties of Capsicum annuumL. were prepared and their phenylpropanoids content was analysed by HPLC. There were seven different compounds identified at varying concentrations depending on pepper variety (L-phenylalanine, t-cinnamic acid, o-coumaric acid, mcoumaric acid, ferulic acid, caffeic acid and capsaicin) which are intermediates of the capsaicinoids pathway. The inhibitory action of the pepper extracts was evaluated against Listeria monocytogenes Murray, Webb and Swann Scott A by the agar diffusion test. Results showed that three of the 10 extracts had an antibacterial effect. Guajillo San Luis pepper presented the highest inhibitory effect, and contained the major concentration of cinnamic and caffeic acids. In order to analyse the individual contribution of every phenylpropanoid to the bacteriostatic effect, different concentrations were tested on the growth and survival of L. monocytogenesSwann Scott A.There were no significant differences (p> 0.05) in the t-cinnamic, o-coumaric, m-coumaric, ferulic acids and capsaicin among the samples. However, a significant difference was found between these compounds and the bactericidal action of caffeic acid. The results confirmed that L. monocytogenesSwann Scott A is inhibited by some pepper extracts, and also that some specific phenylpropanoids had a bacteriostatic effect.

Biochemical and Molecular Analysis of Some Commercial Samples of Chilli Peppers from Mexico

The genus Capsicum provides antioxidant compounds, such as phenolics and carotenoids, into the diet. In Mexico, there is a wide diversity of species and varieties of chilli peppers, a fruit which has local cultural and gastronomic importance. In the present study, the relationship of the carotenoid and phenolic profiles with the RAPD fingerprint of three different commercial cultivars of chilli peppers of seven regions of Mexico was investigated. Through RAPD, the species of chilli were differentiated by means of different primers (OPE-18, MFG-17, MFG-18, C51, and C52). The genetic distance found with OPE 18 was in the order of 2.6. The observed differences were maintained when the chromatographic profile of carotenoids, and the molecular markers were analyzed, which suggest a close relationship between carotenoids and the genetic profile. While the chromatographic profile of phenols and the molecular markers were unable to differentiate between genotypes of chilli peppers. In addition, by using infrared spectroscopy and statistical PCA, differences explained by geographic origin were found. Thus, this method could be an alternative for identification of chilli species with respect to their geographic origin.

Application of Osmotic Dehydration Processes to Produce Apple Slices Enriched with β-Carotene

The objective of this work was the impregnation of β-carotene in apple slices by osmotic dehydration (OD) at atmospheric pressure and by pulsed vacuum osmotic dehydration (PVOD). Osmotic solutions were sucrose solutions of 30, 40, and 50 °Brix containing β-carotene (0.01 g/mL). Maximum impregnation using OD treatments was 1.5, 3.5, and 4.1 mg β-carotene/g ds. When using PVOD, significantly shorter processing times were required and impregnation reached 4.7, 5.5, and 6 mg β-carotene/g ds. Values of aw obtained by OD were 0.973, 0.967, and 0.960 while by PVOD were 0.960, 0.930, and 0.880. Results showed that PVOD was a good option to impregnate apple with β-carotene.

Effects of high hydrostatic pressure on the structure of bovine α-lactalbumin

The effects of high hydrostatic pressure (HHP) processing (at 200 to 600 MPa, 25 to 55 degrees C, and from 5 to 15 min) on some structural properties of alpha-lactalbumin was studied in a pH range of 3.0 to 9.0. The range of HHP processes produced a variety of molten globules with differences in their surface hydrophobicity and secondary and tertiary structures. At pH values of 3 and 5, there was a decrease in the alpha-helix content concomitant with an increase in beta-strand content as the pressure increased. No changes in molecular size due to HHP-induced aggregation were detected by sodium dodecyl sulfate-PAGE. All samples showed higher thermostability as the severity of the treatment increased, indicating the formation of a less labile structure related to the HHP treatment.

The effect of cocoa, soy, oats and fish oil on metabolic syndrome in rats

BACKGROUND The effect of functional foods alone or in combination (cocoa + soy + oats + fish oil) on hepatic damage in rats affected with metabolic syndrome was investigated. RESULTS Rats that were given cocoa showed a decrease in the levels of triglycerides (TGs) and glucose (63 and 32% respectively) as well as a decrease in blood pressure (15%). Animals fed with soy showed a reduction of 21% in total cholesterol, 15% in blood pressure and 44% in TGs, while feeding oats reduced the concentration of TGs by 53% (P < 0.5). Fish oil caused a reduction in TGs (56%) and glucose (26%). The effect on blood pressure was statistically significant for the groups supplemented with cocoa, soy, cocoa + oats and the total mix. The main finding was a reduction in liver steatosis in animals supplemented with cocoa + oats (from 30 to 4.7% steatosis). Cocoa or fish oil alone did not protect the liver from damage, while cocoa + fish oil did. CONCLUSION The most relevant effects were that the cocoa + oats mix decreased steatosis by a very large percentage, as did the cocoa + fish oil mix and the mix of all four functional foods.

Oligomerization of 10,16-dihydroxyhexadecanoic acid and methyl 10,16-dihydroxyhexadecanoate catalyzed by lipases.

The main monomer of tomato cuticle, 10,16-dihydroxyhexadecanoic acid (10,16-DHPA) and its methyl ester derivative (methyl-10,16-dihydroxyhexadecanote; methyl-10,16-DHHD), were used to study their oligomerization reactions catalyzed by five lipases: Candida antarctica lipase B (CAL-B), Rhizomucor miehei lipase (RM), Thermomyces lanuginosus lipase (TL), Pseudomonas cepacia lipase (PCL) and porcine pancreatic lipase (PPL). For 10,16-DHPA, optimum yields were obtained at 60 °C using toluene and 2-methyl-2-butanol (2M2B) as solvent, while for methyl-10,16-DHHD the bests yields were obtained in toluene and acetonitrile. Both reactions leaded to linear polyesters according to the NMR and FT-IR analysis, and there was no data indicating the presence of branched polymers. Using optimized conditions, poly(10,16-DHPA) and poly(methyl-10,16-DHHD) with Mw = 814 and Mn = 1,206 Da, and Mw = 982 and Mn = 860 Da, respectively, were formed according to their MALDI-TOF MS and ESI-MS data. The self-assembly of the polyesters obtained were analyzed by AFM.

Halotolerance and Survival Kinetics of Lactic Acid Bacteria Isolated from Jalapeño Pepper (Capsicum annuum L.) Fermentation

The microbiota associated with spontaneous fermentation of vegetables in a saline substrate may represent an important group of bacteria in the food industry. In this work, the lactic acid bacteria (LAB) Weissella cibaria, Lactobacillus plantarum, Lactobacillus paraplantarum, and Leuconostoc citreum were identified by partial 16S rRNA gene sequence analysis. In addition, entophytic bacteria such as Pantoea eucalypti, Pantoea anthophila, Enterobacter cowanii, and Enterobacter asburiae were detected, but they were irrelevant for the fermentation process and were inhibited after 12 h of fermentation when the pH decreased from 6.5 to 4.9. Moreover, 2 species of yeast were isolated and identified as Hanseniaspora pseudoguilliermondii and Kodamaea ohmeri by their partial 26S rRNA gene sequence. The growth of LAB was evaluated at different sodium chloride contents. L. citreum was the most halotolerant species followed by L. plantarum and W. cibaria with a concentration index to obtain a 50% population reduction (IC(50)) of 7.2%, 6.6%, and 5.2%, respectively. Furthermore, the growth of LAB and Escherichia coli O157:H7 was evaluated in the presence of the main phenylpropanoids from chilli peppers such as p-coumaric and ferulic acid. It was determined that LAB can grow in both acids at 4 mM, unlike E. coli O157:H7, whose growth is inhibited in the presence of these acids.

Functional properties of Ditaxis heterantha proteins

Abstract Ditaxis heterantha is a plant of the Euphorbiaceae family that grows in semiarid regions of Mexico. It produces yellow pigmented seeds that are used for coloring of foods. The seeds contain about 20% of proteins. Proteins of D. heterantha were extracted and fractionated on the basis of solubility. Three main protein fractions were obtained: glutelins, 488 ± 0.5; albumins, 229 ± 2; and total globulins, 160 ± 1 g/kg. The amino acid profile was evaluated for each fraction and protein isolated, where the protein isolate contains essential amino acids such as Val, Phe, Tyr, and Leu. A calorimetric study showed that globulins and glutelins have a high denaturing temperature between 100 and 106°C, while albumins showed a denaturing temperature at 76°C. The protein isolate and its fractions exhibited functional properties: the isolated protein demonstrated good oil‐holding capacity of 40.7 g/kg. Foam capacity (FC) and foam stability (FS) were observed principally in glutelins and globulins where FC maximum was 330% and the FS was 28 min. The emulsifying capacity was observed in the same fractions of glutelins and globulins, followed by albumins. However, the glutelin fraction in particular was the only fraction that exhibited emulsifying stability at pH 5, 6, and 7. Gelling capacity was observed in albumins and globulins. This study indicated that protein isolated from D. heterantha could be used in food formulations due to its essential amino acid profile. Glutelin could be used as an emulsifying additive. Additionally, glutelin and globulin were stable at temperatures above 100°C; this is an important factor in food industry, principally in heat processes.

The prothrombotic state associated with obesity-induced hypertension is reduced by cocoa and its main flavanols

BACKGROUND Little is known about the effects of cocoa and its main flavanols on the prothrombotic state associated with the development of hypertension in diet-induced obesity models. PURPOSE To evaluate the effects of cocoa powder, cocoa extract and their main flavanols on plasma biomarkers related to impaired coagulation and fibrinolysis and its association with hypertension and obesity-related metabolic disorders in rats fed a hypercaloric diet. METHODS Male Wistar rats were randomly assigned to 7 treatment groups (n = 7): normal diet (ND); hypercaloric diet control group (HCD); HCD + cocoa powder (CO); HCD + cocoa extract (CO-EX); HCD + (-)-epicatechin (EPI); HCD + (+)-catechin (CAT); and HCD + procyanidin B2 (PB2). Blood pressure was measured using the tail-cuff method (week 7). At the end of the experimental period (week 8), rats were sacrificed and blood samples were collected immediately for coagulation and biochemical analyses. RESULTS Oral administration of CO, CO-EX and their main flavanols significantly decreased plasma biomarkers related to impaired coagulation and fibrinolysis (vWF, FVIII, fibrinogen and PAI-1) in rats fed a hypercaloric diet. These effects were associated with decreased systolic and diastolic blood pressure, aortic oxidative stress (MDA levels) and improvement of dyslipidemia, insulin resistance and circulating markers of inflammation (TNF-α, IL-6 and CRP) compared to the HCD group. CONCLUSION Our results showed that cocoa and its main flavanols may improve endothelial dysfunction and exert their antihypertensive effects by decreasing the prothrombotic state in rats fed a hypercaloric diet. Moreover, improvement of obesity-related metabolic disorders may also contribute to their BP-lowering effect.