Authors:G. Fontanari, J. Batistuti, G. Bannach, I. Pastre, E. Ionashiro, and F. Fertonani
The guava seed protein isolate (PI) was obtained
from the protein precipitation belonging to the class of the gluteline (Ip
4.5). The conditions for the preparation of the PI were determined by both
the solubility curve and simultaneous thermogravimetry-differential thermal
analysis (TG-DTA): pH 11.5, absence of NaCl and whiteners and T=(253)C.
Under these conditions a yield of 77.00.4%, protein content of 94.20.3,
ashes 0.500.05% and thermal stability, T=200C,
were obtained. The TG-DTA curves and the PI emulsification capacity study
showed the presence of hydrophobic microdomains at pH 11.5 and 3.0 suggesting
a random coil protein conformation and, to pH 10.0, an open protein conformation.
The capacity of emulsification (CE), in the absence of NaCl, was verified
for: 1 – pH 3.0 and 8.5, using the IP extracted at pH 10.0 and 11.5,
CE≥3435 g of emulsified oil/g of protein; 2 – pH 6.60 just
for the PI obtained at pH 11.5, CE≥1408 g of emulsified oil/g of