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Accueil du site → Master → Mexique → Maestría → Efecto del secado por aspersión en la estabilidad de componentes bioactivos de tuna morada Opuntia ficus-indica

Instituto Politécnico Nacional (IPN) 2014

Efecto del secado por aspersión en la estabilidad de componentes bioactivos de tuna morada Opuntia ficus-indica

Castro Muñoz, Roberto

Titre : Efecto del secado por aspersión en la estabilidad de componentes bioactivos de tuna morada Opuntia ficus-indica

Auteur : Castro Muñoz, Roberto

Etablissement de soutenance : Instituto Politécnico Nacional (IPN)

Grade : Maestria en Ciencias en Bioprocesos 2014

Résumé
The purple cactus pear (Opuntia ficus indica var. Stricta) is a fruit grown primarily in semiarid areas ; it has a high content of bioactive compounds as antioxidants. These components are unstable in the presence of light, oxygen, sudden changes in temperature and pH. Therefore, the main objective of this work was to evaluate the stability of cactus pear juice subjected to spray drying process. The selected fruits were visually healthy without postharvest damage and subsequently washed and disinfected previous to extraction process. The juice obtained by extraction showed a yield of 42.45 ± 2.53 %, this juice was then subjected to a process of clarification by ultrafiltration (membrane 100kDa), analyzing the filtrate flux at different transmembrane pressures and concentrations. In addition extracted juice was determined the presence of secondary metabolites (flavonoids and reducing sugars). By HPLC were identified and quantified the main bioactive components determined as betalains in the clarified juice (43.04 ± 0.02 betacyanins / 100g and 19.64 ± 0.02 mg betaxantinas / 100g mg) with antioxidant capacity of 14.35 ± 1.19 TEAC. The clarified juice was microencapsulated using spray dried with maltodextrin and gelatin as encapsulating agents, using a mixture experimental design with 3 replications at the center point and temperature of 110 ° C to 140 ° C. Microencapsulated juice showed recovery yield 7-14 % and the color characteristics of the microencapsulated were : h ° : 15- 29, L : 16- 37, C : 18- 43 IO : 77- 189, with moisture values of 2-6%, water activity from 0.19 to 0.29, hygroscopicity 14- 28 g agua/100g and solubility values of 70-99 %). Regarding the content of pigment concentrations were obtained betalaínas/100g 11-35 mg), with antioxidant capacity 4- 29 TEAC. These results indicate that a drying temperature does not affect the antioxidant activity, the ratio of encapsulating of 2.5 % gelatin and 7.5 % maltodextrin, which showed the highest value of the activity. Furthermore analysis of scanning electron microscopy (SEM) microencapsulated juice in these conditions showed spherical shapes and particle sizes of 1 - 12 µm. Microencapsulated analysis by differential scanning calorimetry (DSC) showed a melting point between 205-235 ° C, finally the sorption isotherms showed moisture values in the monolayer of 8.5 - 9.5 % in storage temperature range of 15 - 30 ° C.

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