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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- 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.
- Combined effect of ultrasound treatment and phytohormones on the accumulation of bioactive compunds in broccoli florets(2017-05-27) Aguilar Camacho, Miguel; Jacobo Velázquez, Daniel Alberto; Wrlti Chanes, Jorge Santos; Benavidez Lozano, Jorge AlejandroIn the past years, postharvest abiotic stresses such as wounding, modified atmospheres, UV-radiation, and the exogenous application of ethylene (ET) and methyl jasmonate (MJ) have been studied as an effective tool to improve the accumulation of bioactive compounds in fresh produce. In this context, previous reports in literature suggest that non-thermal processing technologies such as ultrasound (US) activate the biosynthesis of nutraceuticals in crops by a similar mechanism exerted by wounding stress. However, there is still limited information in literature regarding emerging technologies and their effect on the biosynthesis of bioactive compounds. Therefore, the present thesis evaluated the immediate and late response to US treatment (20 min, frequency 24 kHz, amplitude 100 μm) on glucosinolates, isothiocyanates, phenolic compounds and ascorbic acid in broccoli florets. Moreover, the combined effects of US with exogenous MJ (250 ppm) and/or ethylene ET (1000 ppm) on the content of bioactive compounds were also evaluated during storage (72 h at 15 ºC) of broccoli florets. As an immediate response to US treatment, the extractability of glucosinolates such as glucoraphanin (795%), 4-hydroxy glucobrassicin (153%), and glucobrassicin (78.6%) increased as compared with the control (CT), and induced the detection of gluconasturtiin (0.30 mmol/kg) not identified in the control. Furthermore, US treatment increased the extractability of 1- sinapoyl-2-feruloylgentiobiose (57.23%) as compared with the control, whereas the concentration of the other phenolic compounds remained unaltered. Similarly, the content of total ascorbic acid remained unchanged immediately after US treatment. The enhanced extractability of some bioactive compounds was attributed to cell disruption by US treatment. During storage, gluconasturtiin and 4-methoxy glucobrassicin, which were not detected in CT samples before storage, showed accumulation at 24 h (0.69 mmol/kg) and 72 h (0.29 mmol/kg) of storage, respectively. On the other hand, the content of glucoraphanin and 4- hidroxy glucobrassicin, which were immediately increased by US treatment, remained stable during storage in US samples. However, the high increased content of gluconasturtiin and 4- methoxy glucobrassicin at 24 h and 72 h of storage in CT samples, was not detected in US samples. The combined application of MJ and US in broccoli florets, induced a synergistic effect on the accumulation of 4-hydroxy glucobrassicin, glucoerucin, gluconasturtiin and neoglucobrassicin at 72 h of storage, showing 187.1%, 111.92%, 755.9% and 232.8%, respectively, higher content as compared with US 72 h samples. When ET was applied on US samples, it impeded the accumulation of gluconasturtiin at 24 h of storage, whereas the accumulation of 4-methoxy glucobrassicin (0.52 mmol/kg) was slightly induced at 72 h. Interestingly, when the three stressors where applied together (US+MJ+ET) the synergistic effect of US and MJ observed on the accumulation of 4-hydroxy glucobrassicin, glucoerucin, gluconasturtiin and neoglucobrassicin at 72 h of storage was repressed. Regarding with phenolic compounds the application of US increased the accumulation of 5-O-CQA (70.6%) and 1,2,2-TSG (56.4%) at 72 h and 24 h of storage, respectively, whereas the content of CA (29.8%) decreased at 48 h, as compared with CT samples. Similar to glucosinolates, after 72 h of storage, US and MJ showed a synergistic effect on the accumulation of 3-O-CQA, 1-S-2-FG, and 1,2,2-TSG, showing 73.4%, 56.0% and 136.7%, respectively, as compared with 72h CT+MJ samples. Interestingly, the application of ET did not modify the effect exerted by US on the accumulation of individual phenolic compounds. Likewise, the application of the three stressors in broccoli florets (US+MJ+ET samples) inhibited the accumulation of 3-O-CQA, 1-S-2-FG, and 1,2,2-TSG observed in US+MJ samples stored for 72 h. In general, the ascorbic acid content decreased in most samples during storage. Samples treated with US alone did not show significant differences in the ascorbic acid content during storage when compared with CT samples. However, when MJ+ET were applied, the content of total ascorbic acid was significantly reduced in CT+MJ+ET and US+MJ+ET samples after 72 h of storage by 53.4% and 86.6%, respectively, as compared with CT 0h samples. Based on the results herein obtained, the application of US can be an effective tool to enhance the extractability of certain glucocosinolate and pheniolic compounds in broccoli. Moreover, due to the synergistic effect observed on the accumulation of bioactive compounds, the combined application of US and MJ could be an effective approach to yield higher levels of glucosinolates and phenolic compounds in broccoli during storage. Additionally, recommendations for future investigations such as different US conditions, individual isothiocyanates analysis and analysis of gene expression were proposed in order to better understand the synergistic effect excerted by US and MJ on the accumulation of bioactive compounds in broccoli florets.