Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Efecto del secado por aspersión en la actividad hipoglucemiante de jugo de xoconostle (Opuntia joconostle)

Auteur : Gorostiola Espinosa, Heidi

Etablissement de soutenance : Instituto Politécnico Nacional (IPN)

Grade : Maestría en Ciencias en Bioprocesos 2018

Résumé
The genus Opuntia (cactus pear), which growth in arid and semi-arid climates, being considered valuable vegetable foods in Latin America. Particularly the genus Opuntia joconostle (Xoconostle) have been used in folk medicine as a treatment for diabetes, hypertension, obesity and respiratory ailments. Xoconostle is one of the few sources of betalains in nature and few scientific studies regarding the presence of phenols or other antioxidant compounds. However, stability is an important parameter to consider when using these compounds as antioxidants and colors in foods. Stability of betalains and other antioxidant compounds is affected by pH, exposure to light, oxygen, temperature and enzymatic activities, nonetheless, the temperature is an important factor for betalains degradation. Therefore, the stabilization of bioactive compounds could be improved using microencapsulation technologies, such as spray drying. Different types of encapsulating agents have been used for spray drying ; these include polysaccharides, lipids, and proteins. However, little research has been reported on the encapsulation of xoconostle juice by spray-drying employed gelatin and cactus mucilage as encapsulating agents. The aim of this study was to evaluate the effect of temperature and ratio of gelatin/cactus mucilage as encapsulating agents on the bioactive compounds yields using spray drying, and the stability of the powders obtained. Also, it was evaluated the effect of the powders on lowering blood glucose in a mouse model. Antioxidant activity of xoconostle juice and the powder was evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl). Data showed that compounds from green cactus pear exhibited significant higher DPPH radical-scavenging than pink and red cactus pear. The same behavior was observed in xoconostle powders, where the higher antioxidant activity was found in cactus pear encapsulated with cactus mucilage 2% at 140°C. The response surface analysis (RSM) for the encapsulation efficiency green juice showed xoconostle showed that the inlet air temperature and gelatin/cactus mucilage ratio had a significant effect (p < 0.05) for all the systems under study. The systems containing gelatin 2% at 140 °C and cactus mucilage 1.5% at 132.5°C had better drying yield. On the other hand, the hypoglycemic effect of green cactus pear was demonstrated in experimentally induced diabetic mice. Juice, powder from xoconostle juice and control drug (glibenclamide) had a significant effect for hypoglycemic effect.

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