15D-33 |
Structure/function modification of b-lactoglobulin and egg white proteins by pulsed electric fields. |
O. E. PÉREZ and A. M. R. Pilosof. Departamento de Industrias, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, 1428, Argentina High intensity pulsed electric fields (PEF) is one of the most innovative technologies for food preservation in order to produce higher quality products. In addition to microbial cell count reduction, enzymes may be inactivated by PEF. We hypothesize that similarly to enzymatic proteins, the structure-function of protein components of foods may be altered by PEF. The objective of present work was to determine if PEF treatment could alter protein structure and related functional properties, i. e, gelling behavior. To this end two protein systems, b-lactoglobulin (b-lg, 10%, pH=7) and fresh egg white (EW) were subjected to 1-20 pulses of 12.5 kV/cm. Protein denaturation and aggregation were determined by differential scanning calorimetry and PAGE-electrophoresis. The gelling time was determined by a tilting test. The results showed that, both b-lg and EW, were increasingly denatured by enhancing the number of pulses. Low molecular aggregates were formed in b-lg upon PEF treatment (3-15) pulses, but no significant changes in EW protein bands were observed. The temperature for b-lg and EW gelation was increased by PEF treatment. However, the gelling times were decreased when heating at the appropiate (higher) temperatures. These results suggest that PEF induces structural changes in proteins and modifies their functional performance. Therefore, PEF treatment conditions must be optimized in order to achieve the desired microbiological control of foods with minimal alteration of product quality.
Session 15D, Food Engineering: Processing Technologies
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