99E-16 |
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H. Mújica-Paz, Facultad de Ciencias Quimicas, Univ. Autonoma de Chihuahua, Av. Universidad S/N, Chihuahua, 31170, Mexico, O. Martínez-García, Univ. Autónoma de Chihuahua, Chihuahua, 31170, Mexico, E. Ortega-Rivas, J. WELTI-CHANES, Ingenieria Quimica y Alimentos, Univ. de las Americas-Puebla, Cholula, Puebla, 72820, Mexico, and A. Valdez-Fragoso, Facultad de Ciencias Químicas, Univ. Autónoma de Chihuahua, Chihuahua, 31170, Mexico. Pickling is an old preservation method consisting of the immersion of vegetables in acidified brines. Residual pickling solutions can not be reused in subsequent pickling processes due to their high yeasts count and the presence of polygalacturonase, which produces vegetable softening. It has been reported the potential of high pressure homogenization on reduction of enzyme activity and microbial population of liquid foods, as an alternative for the thermal treatment. This work was conducted to study the effect of high pressure homogenization cycles on polygalacturonase activity and yeasts survival of residual pickling solutions. Residual solutions from pickling process of six vegetables were studied. Each pickling solution was pumped through a homogenizer valve at a pressure of 69 MPa, and it was re-circulated up to 15 times. Yeasts count and polygalacturonase activity were determined in treated solutions after the high pressure cycles 1, 2, 5, 10, and 15. Untreated and thermal treated pickling solutions (80° C for 10 min) were also analyzed. Yeast population resulted in a reduction of 4 log cycles after 5 high pressure cycles, contrasted with a reduction of only 2 log cycles in thermal treatment. No clear relationship between enzyme inactivation and the number of high pressure cycles or thermal treatment was observed. The results indicated that high pressure cycles were effective for the inactivation of yeasts in pickling solutions.
Session 99E, Nonthermal Processing: General II
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |