Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Low intensity pulsed electric fields as an alternative to scalding in the curing of Vanilla planifolia beans(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024) Gutiérrez Sánchez, Amado; Escobedo Avellaneda, Zamantha Judith; mtyahinojosa, emipsanchez; Rodríguez López, Carlos Eduardo; Chuck Hernández, Cristina Elizabeth; Escuela de Ingeniería y Ciencias; Campus Monterrey; Welti Chanes, JorgeVanilla bean curing remains a highly manual and traditional procedure that requires long periods of time and reduces the level of activity of endogenous enzymes related to the production of vanillin and other aromatic compounds due to heat application in the killing step. Pulsed electric fields (PEF) are a non-thermal technology that acts by generating pores in the membrane and cell wall, and it has also been observed that it can modify enzyme activity and increase the content of metabolites such as phenolic compounds. PEF could be an alternative to high-temperature blanching during vanilla curing to improve vanillin content and accelerate the curing process. This work evaluated the effect of low field strength PEF (~1.2 kV/cm, 100 Hz) at different energy density inputs (kJ/kg) as a killing method for curing. Its effect was compared against blanched (control) pods on moisture loss rate, phenolic compounds content and the activity of β-D-glucosidase (BGLU) and phenylalanine ammonia lyase (PAL) enzymes during specific sweating/drying cycles. PEF (100P and 250P) reached a maximum vanillin content at cycle 5, exceeding scalded pods by 60%. They also hydrolyze glucovanillin a 54% (k=0.463 day-1) and 26% ( k=0.376 day-1) faster than blanching. PEF condition 750P can reduce drying time by 6.2%. BGLU activity was reduced <95% after blanching, whereas using PEF preserved or even increased activity by 24% and 11% (20P and 100P). PEF (100P) increased PAL activity (200%) at cycle 0 and maintained residual activity until cycle 3 (2%). PEF (4.5-32.7 kJ/kg) better preserves enzyme activity increases vanillin accumulation, and can reduce drying time; thus, accelerating the beneficiation process or increasing vanillin yield.
- Functionalization of phenolics-rich pigments from purple corn (Zea mays L.) by an enzymatic treatment as a strategy to improve thermal stability and bioactivity(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022-11-17) Yañez Apam, Jimena; Luna Vital, Diego Armando; puemcuervo, emipsanchez; Gutiérrez Uribe, Janet Alejandra; Mata Gómez, Marco Arnulfo; School of Engineering and Sciences; Campus Monterrey; Herrera González, María AzucenaThe impact of enzymatic treatment of Candida antarctica lipase B on a phenolics-rich extract from purple corn (Zea mayz L.) (PCE) was evaluated. PCE was obtained by solid-liquid extraction with 80% ethanol. PCE was treated with lipase B in acetonitrile using octanoic acid as acyl donor for 72 h. Treated and non-treated PCE were tested for thermal stability at 80°C, α-glucosidase inhibitory activity, and molecular docking. The enzymatic treatment promoted the generation of a reaction product identified by HPLC-UV along with a bathochromic shift (530 nm to 570 nm) in the PCE. Enzymatic treatment increased (p < 0.05) the half-life of total monomeric anthocyanins in solution at 80°C from 6.05 to 10.05 h. Additionally, enhanced (p < 0.05) the α-glucosidase inhibitory activity at a concentration of 0.5 mg eq. C3G/L (11.7% non-treated and 33.2% treated). Molecular docking using predicted acylated structures of major anthocyanins in PCE was correlated with biochemical evaluation on α-glucosidase; for instance, cyanidin-3-(6″-n-octanoyl)-glucoside (-9.4 kcal/mol) had a more favorable binding energy than non-acylated cyanidin-3-O-glucoside (-8.4 kcal/mol) with the catalytic site of α-glucosidase. A ligand-protein interaction analysis showed that the acyl group plays an important role stabilizing anthocyanins in the catalytic cavity of α-glucosidase. The results suggest that treatment with lipase B is a promising strategy to improve technological and biological potential of pigments from purple corn.
- Effects of uvb light, wounding stress and storage time on the biosynthesis of betalains, phenolic compounds and ascorbic acid in red prickly pears (opuntia ficus-indica cv. Rojo vigor)(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2018-05-14) Ortega-Hernández, Erika; Jacobo Velázquez, Daniel Alberto; Benavides-Lozano, Jorge; Cisneros-Zevallos, Luis; Welti-Chanes, JorgeUVB light In the past years, abiotic stresses such as wounding and ultraviolet radiation have been studied as an effective tool to improve the accumulation of bioactive phytochemicals in fresh produce. Postharvest application of UVB-radiation and wounding stress induces the accumulation of secondary metabolites in horticultural crops. However, there are few studies evaluating the combined effects of both stresses Therefore, the present thesis evaluated, on the one hand, the separated and combined effects of UVB radiations and wounding stress on the total content of betalains, phenolic compounds and ascorbic acid in red prickly pear (Opuntia Ficus-Indica cv. Rojo Vigor) treated with UVB light (6.4 W•m-2) for 0, 15, 90 and 180 min, before and after storage (24 h at 16 °C); and on the other hand, the effects of UVB radiations and wounding stress, alone or in combination, on the profile of individual betalains and phenolic compounds, as well as the activity of the enzymes involved in their biosynthesis, in red prickly pear treated with UVB light (6.4 W•m-2) for 0 and 15 min, before and after storage (24 h at 16 °C). The highest phenolic accumulation occurred 24 h after UVB treatment (15 min) in whole pulp and peel, increasing by 125.8% and 33.8%, respectively. In the whole fruit pulp, there was a significant increment in kaempferol (64.5%), sinapoyl malate (187.7%), 1-O-β-D-Glucopyranosyl sinapate (57.7%), rosmarinic acid (584.5%), vanillic acid (15.1%), sinapic acid (23.3%), quercetin3-O-glucoside (28.4%) and kaempferol 3-O-sophoroside-7O-glucoside (57.7%). On the other hand, the whole fruit peel showed an increment in the content of kaempferol (631.5%), sinapoyl malate (172.7%), 1-O-β-D-Glucopyranosyl sinapate (505.7%), rosmarinic acid (394.5%), p-coumaric (53.9%), sinapic acid (639.3%), quercetin3-O-glucoside (133.4%), kaempferol 3-Oglucoside (160.9%), quercetin (425.2%) and kaempferol 3-O-sophoroside-7O-glucoside (63.7%). The increment in the PAL activity (1173.5% in pulp and 239.3% in peel) after 12 h of storage corresponds to the increment in content of phenolics. The highest betalain accumulation occurred 24 h after UVB treatment (15 min) in whole pulp and wounded peel, increasing by 49.8% and 33.1%, respectively. The whole fruit pulp showed a significant increment in muscaaurin VII (293.6%), indicaxanthin (316%), betanin (26.2%) and iso-betanin (70.6%); whereas vulgaxanthin III (-21.1%), betanidin (-78.9%), neobetanidin (-87.3%) and gomphrenin (-55.4%) decreased. On the other hand, the wounded fruit peel showed a significant increment in muscaaurin VII (33.2%), indicaxanthin (159.1%), betanin (161.8) and iso-betanin (98.7%). The increment in the TYR hydroxylase (744.1% in pulp and 332.9% in peel) and TYR oxidase activity (81.6% in pulp and 59.2% in peel), as well as cyclo- Dopa formation (637.2% in pulp and 439.3% in peel) after 12 h of storage corresponds to the increment in content of betalains. The highest ascorbic acid accumulation occurred 24 h after UVB treatment in wounded pulp and peel, increasing by 67.2% and 84.6%, respectively. The increment in the GalLDH activity (85.4% in pulp and 502.3% in peel) after 12 h of storage corresponds to the increment in content of ascorbic acid.Results indicated that the application UVB light alone or combined with wounding stress in red prickly pear can be used as an effective strategy to induce the accumulation of secondary metabolites with potential application in the food, dietary supplements and pharmaceutical industries; since these postharvest treatments are low cost, have no legal restrictions, and do not require complex equipment.