Sergio I. Martínez-Monteagudo

Chemical Reactions in Food Systems at High Hydrostatic Pressure

The combination of high hydrostatic pressure and temperature has become a valuable alternative to produce superior quality products in cases where the traditional thermal treatments have failed to deliver high-quality products. Unfortunately, the impact of pressure on chemical reactions in food systems is often overlooked. This review summarizes studies on chemical reactions in various food systems that have been qualitatively and quantitatively evaluated under high pressure at either ambient, moderate, or elevated temperatures. In addition, a critical discussion on the current approaches was used to evaluate the reaction rates, and therefore, the reaction mechanisms of some food systems are provided. Activation volume and activation energy of various food systems treated by high hydrostatic pressure are also provided. Finally, the need of kinetic studies in food systems is highlighted.

Combined effect of pressure-assisted thermal processing and antioxidants on the retention of conjugated linoleic acid in milk

The effect of pressure-assisted thermal processing (PATP) in combination with seven synthetic antioxidants was evaluated on the retention of conjugated linoleic acid (CLA) in enriched milk. Milk rich in CLA was first saturated with oxygen, followed by the addition of either catechin, cysteine, ascorbic acid, tannic acid, gallic acid, caffeic acid or p-coumaric acid (500 mg kg−1 untreated milk). Samples were treated at 600 MPa and 120 °C up to 15 min of holding time. During PATP, CLA not only oxidized at a slower rate, but also less oxygen was consumed compared to the control (0.1 MPa and 120 °C). In addition, phenolic antioxidants were able to quench dissolved oxygen in samples treated with PATP. For those samples added with gallic acid and catechin, 85% and 75% of the CLA was retained after 15 min of holding time at 600 MPa and 120 °C, respectively. The retention of CLA was enhanced by the application of PATP in combination with gallic acid.