The In Vitro Inhibitory Activity of Pacaya Palm Rachis versus Dipeptidyl Peptidase-IV, Angiotensin-Converting Enzyme, α-Glucosidase and α-Amylase.

The pacaya palm (Chamaedorea tepejilote Liebm) is an important food that is commonly consumed in Mexico and Central America due to its nutritive value. It is also used as a nutraceutical food against some chronic diseases, such as hypertension and hyperglycemia. However, few reports have indicated its possible potential. For this reason, the goal of this research was to evaluate the effects of the enzymatic activity of the pacaya palm inflorescence rachis on both hypertension and hyperglycemia and the effects of thermal treatments on the enzymatic activity. The enzymatic inhibition of ACE (angiotensin-converting enzyme), DPP-IV (dipeptidyl peptidase-IV), α-glucosidase and α-amylase were evaluated, all with powder extracts of pacaya palm inflorescences rachis. The results indicated that thermally treated rachis showed increased enzymatic inhibitory activity against α-amylase and DPP-IV. However, all rachis, both with and without thermal treatment, showed low- or no enzymatic activity against α-glucosidase and ACE. Apparently, the mechanism of action of the antidiabetic effect of rachis is mediated by the inhibition of α-amylase and DPP-IV and does not contribute with a significant effect on enzymes involved in the hypertension mechanism. Finally, the properties of the extract were modified via the extraction method and the temperature tested.

Effects of Germination and Popping on the Anti-Nutritional Compounds and the Digestibility of Amaranthus hypochondriacus Seeds.

Amaranth seeds, although a valuable food in Mexico, contain anti-nutritional compounds that can affect food quality. As a part of this work, the proximate composition, fatty acid profile, protein digestibility, and the effect of germination and popping of Amaranthus hypochondriacus seeds was analyzed with the aim of eliminating anti-nutritional compounds. Untreated seeds comprised of 11.35-18.8% protein and 0.27-13.39% lipids, including omega 3, 6, and 9 fatty acids such as oleic, linoleic, linolenic, and arachidonic acid. The main minerals detected were Ca+2, K+1, and Mg+2. Nevertheless in vitro studies indicate that germination significantly improved digestibility, whereby treatments aimed at reducing anti-nutritional compounds decreased lectin concentration, while significantly increasing tannins and completely eliminating trypsins and saponins.

Antimicrobial Effects of Aqueous Extract from Calyces of Hibiscus sabdariffa in CD-1 Mice Infected with Multidrug-Resistant Enterohemorrhagic Escherichia coli and Salmonella Typhimurium.

To determinate the antimicrobial effect of chloramphenicol and aqueous extract against multidrug-resistant enterohemorrhagic Escherichia coli (EHEC) and Salmonella enterica serovar Typhimurium in CD-1 mice. Aqueous extract was isolated from Hibiscus sabdariffa calyces. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of chloramphenicol and aqueous extract were determined for EHEC and S. Typhimurium. Nine groups of six mice each were formed. Three groups were inoculated orally with 1 × 104 colony-forming units (CFU) of S. Typhimurium, three groups were inoculated with 1 × 104 CFU of EHEC and the remaining three groups were not inoculated. Six hours postinoculation, the mice of some groups were orally administered solutions of aqueous extract (50 mg/mL), chloramphenicol (82 µg/mL), or isotonic saline. The EHEC and S. Typhimurium concentration in all mice feces was determined. For both pathogens, the MIC and MBC values of aqueous extract were 20 y 50 mg/mL, respectively; for chloramphenicol, they were between 17.5 and 82 µg/mL. EHEC and S. Typhimurium were not detected in the feces of mice that were administered aqueous extract on the 2nd and 3rd days posttreatment. Furthermore, these mice recovered from the infection. In contrast, in mice not treated, or treated with chloramphenicol alone, pathogens were isolated from their feces throughout the study, and some mice died. The H. sabdariffa calyx extracts could be an alternative to control multidrug-resistant bacteria in humans and animals.

LEA13 and LEA30 Are Involved in Tolerance to Water Stress and Stomata Density in Arabidopsis thaliana.

Late embryogenesis abundant (LEA) proteins are a large protein family that mainly function in protecting cells from abiotic stress, but these proteins are also involved in regulating plant growth and development. In this study, we performed a functional analysis of LEA13 and LEA30 from Arabidopsis thaliana. The results showed that the expression of both genes increased when plants were subjected to drought-stressed conditions. The insertional lines lea13 and lea30 were identified for each gene, and both had a T-DNA element in the regulatory region, which caused the genes to be downregulated. Moreover, lea13 and lea30 were more sensitive to drought stress due to their higher transpiration and stomatal spacing. Microarray analysis of the lea13 background showed that genes involved in hormone signaling, stomatal development, and abiotic stress responses were misregulated. Our results showed that LEA proteins are involved in drought tolerance and participate in stomatal density.

Modifications of the Protein Characteristics of Pacaya Caused by Thermal Treatment: A Spectroscopic, Electrophoretic and Morphological Study.

The inflorescences of Chamaedorea tepejilote Liebm. are consumed as food in Central America and southern Mexico but is an underutilized food because of its sensory characteristics, principally due to its bitter taste. However, the inflorescences of Chamaedorea tepejilote Liebm. are nutritionally promising due to their high protein content (approximately 25%). Protein isolates from pacaya were modified via three different thermal treatments to determine the effect of the treatments on the protein structures. Scanning electron microscopy indicated that the pacaya protein isolate particles had less rough and irregular surfaces with larger particle sizes due to an aggregation process when a thermal treatment was used compared to those when no thermal treatment was used. An increase in the intensity of the low molecular weight protein fractions (≤20 kDa) in the electrophoretic pattern of the proteins was observed, which was generated by the hydrolysis of the proteins by heat treatment. The modifications in the FT-IR spectra showed that thermal treatment of pacaya affected the secondary structure of its proteins, mainly when microwave treatment was used. Raman spectroscopy revealed that the α-helical structure was dominant in the proteins of pacaya and that thermal treatment increased the fraction of the ß-sheet structure at the expense of the α-helical structure.

Hibiscus Acid and Chromatographic Fractions from Hibiscus Sabdariffa Calyces: Antimicrobial Activity against Multidrug-Resistant Pathogenic Bacteria.

The anti-microbial properties of acetone extracts from Hibiscus sabdariffa calyces, fractions isolated by silica gel chromatography and hibiscus acid purified from some of these fractions and additionally identified by nuclear magnetic resonance spectroscopy, mid-infrared spectroscopy and X-ray diffraction, were studied against both multidrug-resistant Salmonella strains and pathogenic Escherichia coli bacteria. Gel diffusion was used to determine the anti-microbial effects. The mode of action of hibiscus acid was determined by crystal violet assay. Hibiscus acid and 17 of the 25 chromatographic fractions obtained, displayed an anti-microbial effect against all bacterial strains tested. Hibiscus acid showed a greater anti-microbial effect than the acetone extract against most of the bacteria strains, while chromatographic fractions IX-XIV exerted the greatest anti-microbial effect against all bacteria. The minimum inhibitory concentration of the acetone extract was 7 mg/mL, and the minimum bactericidal concentration was 10 mg/mL, while the corresponding values for hibiscus acid were 4-7 and 7 mg/mL, respectively. The results of the crystal violet assay indicate that hibiscus acid alters membrane permeability. Hibiscus acid is a potential alternative to control multidrug-resistant bacteria. Due to its ready availability and easy extraction from H. sabdariffa, hibiscus acid is potentially useful in the food industries.

Effect of Dual Modification on the Spectroscopic, Calorimetric, Viscosimetric and Morphological Characteristics of Corn Starch.

The effect of dual modification of corn starch, including hydrolysis and succinylation, were evaluated through peak viscosity (PV) analysis, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. This dual modification was shown to increase the reaction efficiency (RE) and degree substitution (DS) compared with starches that were not subjected to acid hydrolysis pretreatment with a 44% and 45% increase respectively. After acid hydrolysis pretreatment, the surface of the corn starch granules exhibited exo-erosion and whitish points due to the accumulation of succinyl groups. The peak viscosity was reduced significantly with the acid hydrolysis pretreatment (between 3 and 3.5-fold decrease), which decreased the pasting temperature and peak time to 20 °C and 100 s respectively. In addition, the dual modification of corn starch altered certain thermal properties, including a reduction in the enthalpy of gelatinization (ΔH) and a higher range of gelatinization (around 6 °C), which may effectively improve industrial applications. Modifications on the FTIR spectra indicated that the dual modification affected the starch crystallinity, while the Raman spectra revealed that the dual modification disrupted the short-range molecular order in the starch. Rearrangement and molecular destabilization of the starch components promoted their granular amphiphilic properties.

Chemical, physical and sensory properties of Vienna sausages formulated with a starfruit dietary fiber concentrate.

The use of a starfruit dietary fiber concentrate (SDFC) as a novel ingredient in Vienna sausages was investigated. A constrained mixture design was followed to evaluate the effect of different proportions of SDFC (0-10%), pork meat (0-100%) and turkey meat (0-100%) on the shear force, shrinkage, color, residual nitrite, moisture and polyphenol contents of sausages. Moreover, a chemical, physical and sensory characterization of the optimized formulations was performed. The cubic model equations demonstrated that the SDFC in mixture with pork or turkey meat had a reducing effect on nitrites, moisture, shear force and shrinkage, while there was an increase on the polyphenol concentration as the increase of SDFC proportion in the formulations. The optimization resulted in Vienna-type sausages formulated with a ternary mixture of pork/turkey meat and high SDFC proportion (7.4-8.4%). These products had high total dietary fiber content (11.04-17.79%) and antioxidant polyphenols, low residual nitrite content, shrinkage and red color. They presented good taste, color and texture attributes, and were sensory acceptable. This study demonstrated that enrichment of Vienna-type sausages with SDFC in mixture with pork/turkey meat is a way to obtain potential functional meat products with high antioxidant dietary fiber content, reduced in nitrites, and good physical and sensory properties.

Spectroscopic, calorimetric and structural analyses of the effects of hydrothermal treatment of rice beans and the extraction solvent on starch characteristics.

The modification of the starches extracted from rice beans both with and without hydrothermal treatment was evaluated via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) and Raman spectroscopy. SEM indicated that the starch granules of rice beans exhibit wide variation in granule shape, showing the greatest size and modification of the surface when extracted with ethanol. It was found that the extraction solvent had no significant effect on the onset (To) and peak (Tp) temperatures of the starch, whereas hydrothermal treatment of rice beans decreased the To, Tp and ΔH of the starch. The modification of FT-IR spectra showed that hydrothermal treatment of rice beans and the solvent used in the extraction of starch affected starch crystallinity, mainly when ethanol was used. Raman spectroscopy revealed that the smaller changes in the starch bonds were due to the solvent used for starch extraction but that hydrothermal treatment disturbed all bonds in the starch.

Fourier transform infrared and Raman spectroscopic study of the effect of the thermal treatment and extraction methods on the characteristics of ayocote bean starches.

Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm-1 in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm-1 indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm-1, indicating the product of the retrogradation process. The thermal treatment reduced the crystallinity as well as short-range order. Raman spectroscopy revealed that acute changes occurred in the polysaccharide bonds after thermal treatment. This study showed that the thermal treatment affected the structural properties of ayocote bean starches, the interactions of the lipids and proteins with starch molecules and the retrogradation process of starch.

Quality of Opuntia robusta and its use in development of mayonnaise-like product.

The aim of this study was to characterize Opuntia robusta parenchyma and mucilage as foodstuffs. Solute absorption of Opuntia robusta parenchyma was studied, mucilage was used to develop a mayonnaise-like product as substitute emulsifier alternative to egg yolk and oil substitute. Shelf life of mayonnaise-like product was evaluated. Scanning electron microscopy demonstrated that oxalate calcium crystal were present in the Opuntia robusta parenchyma and mucilage with druses morphology; whereas that in the mayonnaise-like product were not observed calcium oxalate crystals, due probably to the product pH is acidic. The heat treatment of parenchyma at 50 °C, 65°Brix, had highest influence on the solute absorption (about 35 %). Results revealed that best mixture was the formulated with 26.79 % oil, 62.50 % mucilage and 10.71 % whey protein. Mucilage was the component showing the highest effect on all textural characteristics of mayonnaise-like product. The storage temperature had highest effect on the textural characteristics of mayonnaise-like product than storage time. With the right combination of mucilage of Opuntia, oil and whey protein, it is possible to develop a low-fat mayonnaise with functional properties similar to those of commercial mayonnaise.