91E-9 |
High hydrostatic pressure processing of peach puree with and without antibrowning agents |
J. A. GUERRERO-BELTRÁN1, B. G. Swanson2, and G. V. Barbosa-Cánovas1. (1) Biological Systems Engineering Department, Washington State University, Pullman, WA 99164-6120, (2) Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376 Non-thermal technologies, such as high hydrostatic pressure (HHP), have arisen as an alternative for thermal processing of fruit products. Deteriorative enzymes and microorganisms are the main concern in processed fruit products. HHP is a valuable tool to inhibit or destroy both enzymes and microorganisms. However, several studies are needed to assess which variables are important in HHP treatment of fruit products. The objective of this study was to evaluate the effect of HHP and antibrowning agents on natural peach puree. Peach puree (natural, with 1000 ppm of ascorbic acid or with 300 ppm of cysteine were treated with HHP (103-517 MPa) for different lengths (5-25 min) to assess the inhibition of polyphenoloxidase (PPO). PPO activity was analyzed spectrophotometrically before and after HHP treatment. All products were stored for 2 weeks at 3±1°C and then 4 weeks at 22±1°C. L*, a*, and b* color parameters were assessed to evaluate the product's color stability. Natural peach puree showed decreasing PPO activity with increasing pressure and processing time. Dp values obtained by a first order reaction rate were plotted vs. pressure. A Zp value was obtained (244 MPa) from the linear relationship of 207 to 517 MPa (r2=0.948). Peach puree with ascorbic acid showed an increase in PPO activity at low pressures (103-310 MPa) and a decrease in activity at high pressure (414-517 MPa). All products with cysteine showed decreasing PPO activity after HHP treatment. Color differences (DE*) were observed (p<0.05) during storage. No color differences were observed in peach products treated at 414 and 517 MPa. However, natural purees were more stable (DE*=12.7) than purees with ascorbic acid or cysteine after 4 weeks of storage. These results suggest it is possible to obtain more stable natural peach purees than products with added antibrowning agents using HHP (414 or 517 MPa).
Session 91E, Nonthermal Processing: Nonthermal processing of foods
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