Abstract

This paper aimed to carry out the stabilization of phytase produced in solid-state fermentation by means of Aspergillus níger 7A-1 in triticale as substrate. The crude extract obtained in liquid state was stabilized with glycerol and maltose. These materials presented a synergic effect that improve phytase stability around 80% with ki of 0.031 and a shelf-time of 156 days (22.35 weeks) with glycerol 30% and maltose 20%. Besides, microencapsulation by spray drying was used as well to analyze the potential of whey and guar gum to obtain microencapsulates of phytase for monogastric animals. Statistical analysis allowed establishing the suitable temperature at 110°C with a flow of 10% (3.3 ml/min), guar gum concentration of 1% and yield process at 93%. Characterization allows us to observe that microencapsulates with whey and guar gum is a good alternative to be used in spray drying. SEM showed the formation of aggregates with pores. Thermogravimetric analysis demonstrated that thermal stability of guar gum is improved when it is mixed with whey. Infrared showed the signal of protein groups in samples with whey and guar gum. Stability assessment was performed with two different containers, Eppendorf and Ziploc bags, in which it was demonstrated that microencapsulation with whey and guar gum allow the retention of 85% for both containers. At 35°C, phytase activity decreases until 55%. In this study, color was evaluated as well in Ziploc bags with the color observing change during the 8 weeks; this change was not observed in Eppendorf container and it was possible to observe that color does not affect enzymatic stability. Finally, digestibility evaluation demonstrated that whey and guar gum provide protection in gastrointestinal conditions. After digestive system simulation, 90% of activity is retained which allows observing the potential of whey and guar gum to protect enzymes under gastrointestinal condition.

Key words: Phytases, phosphorus, phytate, guar gum, microencapsulation.