Submitted to: Journal of Food Engineering
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/8/2012
Publication Date: 2/1/2013
Citation: Igual, M., Sampedro, F., Martinez-Navarrete, N., Fan, X. 2013. Combined osmodehydration and high pressure processing on the enzyme stability and antioxidant capacity of a grapefruit jam. Journal of Food Engineering. 114:514-521. Interpretive Summary: Fruit jam is a good source of nutrients and phytochemicals. Traditional thermal processing leads to losses of bioactive compounds and deterioration of sensory properties in fruit products. In this study, high pressure in combination with osmodehydration process was evaluated for the production of grapefruit jam. High pressure with elevated processing temperature is an effective method for the stabilization of grapefruit jam without affecting antioxidant properties of the product. Therefore, fruit jam with better nutrients can be produced using the combined processing technologies.
Technical Abstract: A combined osmodehydration process and high pressure treatment (OD-HHP) was developed for grapefruit jam preservation. The inactivation kinetics of pectinmethylesterase (PME) and peroxidase (POD) in the osmodehydrated (OD) jam treated by combined thermal (45-75°C) and high pressure (550–700 MPa) processes were fitted using special cases of first-order kinetics, the fractional conversion and biphasic models and the Weibull distribution function. No complete inactivation was achieved by any combination of temperature and pressure, and 27-40% and 51-70% of PME and POD, respectively, were pressure-stable fractions. Two PME fractions with different pressure stabilities were observed and kinetic models successfully explained that behaviour. POD was found to be very baroresistant and only the labile fraction could be inactivated. The extent of enzyme inactivation was lower in the OD jam in comparison with other food matrices showing a protective effect against the high pressure treatment. The antioxidant capacity was not affected by any treatment. The proposed high pressure preservation processing was able to improve the enzymatic stability of jam obtained by osmotic dehydration without affecting the bioactive content.