José Alberto Gallegos-Infante

Effect of high-pressure homogenization on the physical and antioxidant properties of Quercus resinosa infusions encapsulated by spray-drying.

Quercus resinosa leaves are used in northern Mexico as a refreshing beverage rich in polyphenolic compounds. These leaves show astringency and hence need taste masking for incorporating in a food product. They also interact with many other food components and are not very stable to food processing environments, thus it is important to protect them and a common way is by encapsulation. In the present study the use of encapsulation by spray-drying of Quercus resinosa leaves infusions was evaluated. Q. resinosa leaves were collected, air dried, and milled prior to infusion preparation. Lactose-sodium caseinate blends at 3 different proportions (11 : 4%, 9 : 6%, and 7 : 8%) were dispersed with a constant amount of lyophilized infusion (0.075%) and processed under high-pressure homogenization (0, 100, 200, 300 MPa). Total phenolic content, DPPH kinetic analysis, deoxy-D-ribose oxidation inhibition, rheological evaluation, and particle size analysis were performed to evaluate the obtained capsules. High antioxidant activity was shown by capsules despite their very low concentration when inhibiting deoxy-D-ribose oxidation. Chain breaking rate was related to polyphenolic concentration in capsules. Using lactose-caseinate blends produces capsules of submicron to nanometer size that retain the good antioxidant capacities of original infusions.

Antioxidant, anti-inflammatory and anticarcinogenic activities of edible red oak (Quercus spp.) infusions in rat colon carcinogenesis induced by 1,2-dimethylhydrazine

Red oak (Quercus spp.) leaves are traditionally used as food in Mexico, and some of their infusions have potential anticarcinogenic and anti-inflammatory effects; however, these properties have not yet been scientifically tested. The aim of this work was to explore the anti-inflammatory activity in HT-29 cells and anticarcinogenic effect in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis of red oak infusions. Quercus infusions were prepared and administered as the sole source of drink to male Sprague-Dawley rats (1% w/v) for the entire 26-week experimental period. On week 4, rats received 8 subcutaneous injections of DMH (21 mg/kg body weight) once a week. The results showed that mean tumor (0.9 ± 0.2 vs. 2.6 ± 0.3) and multiplicity (1.2 ± 0.1 vs. 2.0 ± 0.23), and β-catenin protein level (2.2-fold) in adenocarcinomas were significantly lower in Quercus  sideroxyla-treated group compared with DMH group. By contrast, Quercus  durifolia and Quercus  eduardii infusions had no protective effect. Additionally, the experiments in HT-29 cells confirmed that Q. sideroxyla infusion effectively decreased the levels of the inflammatory markers COX-2 and IL-8 by modulating the expression of NF-κB. These results highlight some of the molecular mechanisms related to the chemopreventive effect of Q. sideroxyla infusion and its potential value as a source of bioactive compounds.

Chemical evaluation, antioxidant capacity, and consumer acceptance of several oak infusions.

As part of an ongoing screening on natural products, 4 oak leaves were analyzed as potential nutraceutical beverages. The phenolic composition, antioxidant capacity, and sensory preferences of leaves infusions from Quercus resinosa, Q. sideroxyla, Q. eduadii, and Q. durifolia in comparison with 2 commercial green teas were investigated. Herbal infusions from oak leaves and Green teas (1%, 80 °C, 10 min) were evaluated for total polyphenol content (TPC), total flavonoid content (TFC), HPLC analysis, trolox equivalent antioxidant capacity (TEAC), oxygen radical absorbance capacity (ORAC), soluble solids, pH, color, and consumer preference analysis. Q. resinosa leaves infusions have shown the highest TPC, TEAC, and ORAC values but they have attained the lowest preference score. Quercus leaves infusions with higher content of gallic acid and catechins showed best antioxidant capacity but lower consumer preference.

Antioxidant activity of fractions from Quercus sideroxyla bark and identifi cation of proanthocyanidins by HPLC-DAD and HPLC-MS

Abstract The most active phenolics in Quercus sideroxyla Humb. & Bonpl. residual bark were identified and evaluated following a chromatographic fractionation. Bark powder was defatted with hexane and crude extract (CE) was obtained by extraction with aqueous acetone (70%). A liquid partition with ethyl acetate was performed to produce an organic extract (OE), which was subsequently purified by column chromatography (Toyopearl HW-40F, methanol), and resulted in six methanolic fractions (MF1 to MF6) and an oligomeric fraction (OLF) eluted with acetone 67%. Extraction yields, total phenolic and flavanol contents were determined. The antioxidant activity of bark extracts was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox (6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic-acid)-equivalent antioxidant capacity (TEAC), and ferric ion reducing antioxidant power (FRAP) assays. Their median effective concentration (EC50) data and rate constants for DPPH radical scavenging were also estimated. Identification of major phenolics was carried out by high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography with electrospray ionization coupled to mass spectrometry (HPLC-ESI-MS) instruments. Bioactive gallic acid, catechin, epicatechin, gallocatechin, catechin gallate, dimeric procyanidins, galloylated dimeric proanthocyanidins, trimeric procyanidins, and tetrameric proanthocyanidins were detected and identified in Q. sideroxyla bark extracts. MF2 was the most active fraction containing gallocatechin as its major compound; MF5 and OLF contain galloylated procyanidins, which may explain their higher antiradical activity. OLF besides galloylated procyanidins has gallocatechin, which presumably contributes to its higher antiradical activity. Consequently, Q. sideroxyla bark could be a good source of therapeutic health products or nutraceutical ingredients that may exert a potential prevention or treatment action against diseases in biological systems.

Effect of extrusion conditions on physicochemical characteristics and anthocyanin content of blue corn third-generation snacks

The aim of this study was to evaluate the effect of barrel temperature (BT, 98.8–141.2°C) and feed moisture (FM, 19.93–34.07%) as independent factors on physicochemical characteristics of microwave-expanded extruded third-generation (3G) snacks obtained from blue corn and corn starch. Single-screw laboratory extruder and a central, composite, rotatable experimental design were used. Both independent factors showed significance (p ≤ 0.01) on most of the analyzed responses. The mathematical models showed values of R2Adj ≥ 0.76 and p of F(model) ≤ 0.001. The optimum area of the extrusion process ranged from 120°C to 126°C for BT and from 23.8% to 25.2% for FM. In optimal conditions, the product showed an expansion index of 4.8, a penetration force of 12.42 N, a specific mechanical energy of 169.08 kJ/kg, and 71.09 mg of total anthocyanin content/kg. The developed 3G snack presented high-quality physicochemical characteristics, with the potential health benefits derived from nutraceutical characteristics (dietary fiber and anthocyanins) of the whole blue corn used.

Drying Parameters of Half-Cut and Ground Figs (Ficus carica L.) var. Mission and the Effect on Their Functional Properties

Drying of ground and half-cut figs (Ficus carica L., var. Mission) was investigated at three temperatures (45, 55, and 65°C). Their effective moisture diffusivity () was estimated by using the slope method. values for ground figs were 5.15 × 10−10, 9.96 × 10−10, 1.07 × 10−9 m2 s−1 and for half cut figs 5.88 × 10−10, 1.66 × 10−9, and 2.08 × 10−9 m2 s−1 at 45, 55, and 65°C, respectively. Dehydrating fig samples showed a similar behavior: higher values at higher temperatures and activation energy () values in the range of other foodstuffs. Half-cut figs needed about twice more energy and time than ground figs to carry out the dehydration; values were 56.86 and 28.21 kJ mol−1, respectively. The drying process increased the total phenolic content and degraded the anthocyanin content of figs; however, it enhanced the dried figs antioxidant activity. Dehydrating ground figs was faster and maintained its functional properties better than half-cut figs.

Influence of Commercial Saturated Monoglyceride, Mono-/Diglycerides Mixtures, Vegetable Oil, Stirring Speed, and Temperature on the Physical Properties of Organogels

The objective of this study was to evaluate the influence of gelator, vegetable oil, stirring speed, and temperature on the physical properties of obtained organogels. They were prepared under varying independent conditions and applying a fractional experimental design. From there a rheological characterization was developed. The physical characterization also included polarized light microscopy and calorimetric analysis. Once these data were obtained, X-Ray diffraction was applied to selected samples and a microstructure lattice was confirmed. Commonly, the only conditions that affect crystallization have been analyzed (temperature, solvent, gelator, and cooling rate). We found that stirring speed is the most important parameter in the organogel preparation.

Efecto del procesamiento térmico sobre la capacidad antioxidante de pinole a base de vainas de mezquite (Prosopis laevigata)

El objetivo de este estudio fue obtener un pinole de alta calidad funcional a base de vainas de mezquite (Prosopis laevigata). Se llevó a cabo un diseño factorial (3)2 con tres temperaturas de secado (60, 70 y 80°C) y tres de tostado (140, 150 y 160°C) y una muestra control (pinole sin tratamientos térmicos). Se determinó la caracterización proximal, incluyendo proteína soluble, perfil electroforético, digestibilidad de proteínas; Factores antinutrivos como inhibidores de tripsina, lectinas y fenoles; Actividad antioxidante por inhibición de la oxidación de lipoproteínas de baja densidad (LDL); y Capacidad hipotensiva por la inhibición de la Enzima Convertidora de Angiotensina (ACE). La mayor digestibilidad se encontró a 60°C/160°C (74,43±0,38%). La temperatura de secado más alta (80°C) mostró la mayor disminución de inhibidores de tripsina (73%) y lectinas (186,81 U/mg). Asimismo, los fenoles disminuyeron con un incremento de temperatura (secado y tostado). Los extractos de pinole disminuyeron la oxidación de las LDL y los tratamientos térmicos mostraron efecto sobre la inhibición de la actividad de la ACE.

Mixing and tempering effect on the rheological and particle size properties of dark chocolate coatings Efecto del mezclado y temperado sobre las propiedades reológicas y de tamaño de partícula de coberturas de chocolate oscuro

Chocolate coatings are semisolid suspensions of fine particles from sugar, cocoa, non fat milk solids in an oily phase. Processing steps of chocolate include mixing, refining, conching, tempering, molding, and packing. Tempering is a directed pre-crystallization that consists of shearing chocolate mass at controlled temperatures. The effect of mixing and tempering process on the particle size distribution and rheological behavior of dark chocolate coatings were evaluated. Each sample was melted (65 °C, 15 min) and tempered following three different procedures usually recommended for chocolate. Proximate composition analysis, specific surface area, mean particle diameter, consistency index (K), flow index (n), G′, G″ and electron micrographs (4000×) were obtained. All samples followed Casson flow model and (n) showed a pseudoplastic behavior. Higher values of K were shown by tempering process 3. Shear increased chocolate storage module (G′) and its stability. Samples without tempering and shearing have shown higher values of particle size. Las coberturas de chocolate son suspensiones semi-sólidas de partículas pequeñas de azúcar, cacao, sólidos no grasos de leche en una fase oleosa. Los pasos del procesamiento de chocolate incluyen mezclado, refinación, conchado, temperado, moldeo y empacado. El temperado es una pre-cristalización directa que consiste en cizallar la masa de chocolate a temperaturas controladas. Se evaluó el efecto del mezclado y del temperado sobre la distribución del tamaño de partícula y el comportamiento reológico de coberturas de chocolate obscuro. Las muestras fueron fundidas (65 °C, 15 min) y temperadas siguiendo tres procedimientos recomendados. Se determinaron el análisis proximal, área superficial específica, diámetro medio de partícula, índice de consistencia (K), índice de flujo (n), módulos viscoelásticos (G′ y G″), y se usó micrografía electrónica, SEM (4000×). Todas las muestras presentaron un comportamiento al flujo ajustado al modelo de Casson. Los cambios de K estuvieron en función del proceso de temperado usado, pero (n) mostró cambios en su comportamiento pseudoplástico. Los mayores valores de K se obtuvieron para el temperado 3 y los menores para el temperado 1. El corte incrementó el módulo de almacenamiento (G′) y en consecuencia su estabilidad. Las muestras sin temperado y corte mostraron el mayor tamaño de partícula (9.17 μm).

Chemical composition of biomass generated in the guava tree pruning

Psidium guajava L. (Myrtaceae) is a native plant of Central America and is now widely cultivated in many tropical regions of the world for the fruit production. In Mexico, in the guava orchards common practices to control fruit production are: water stress, defoliation and pruning. In this study, we report the chemical composition of the biomass (branches and leaves) generated in the pruning practices. The results ranged as follows: pH (4.98-5.88), soda solubility (39.01-70.49 %), ash (1.87-8.20 %); potassium and calcium were the major inorganic elements in ash. No heavy metals were detected in the studied samples; total solubility (15.21-46.60 %), Runkel lignin (17.77-35.26 %), holocellulose (26.56 -69.49 %), α-cellulose (15.53-35.36 %), hemicelluloses (11.02-34.12 %), tannins in aqueous extracts (3.81-9.06 %), and tannins in ethanolic extracts (3.42-15.24 %).