Vacuum and steam pasteurization to increase nuts’ shelf-life ?
Knowing that heat treatment can destroy some of the enzymes responsible for the oxidation of nuts, Steripure’s quality team decided to measure the impact of vacuum and steam treatment on nuts’ rancidity.
Over the past two years, we have followed the evolution of macadamia nuts, whole pistachios, walnuts and hazelnuts treated with our process, and compared them with conservatory samples of untreated products from the same batches.
Preliminary results are very promising and we do believe that vacuum and steam treatment can significantly increase nuts’ shelf life.
This perspective is particularly interesting for our customers since, if confirmed, it would allow them to store their products at lower cost without specific precautions such as low temperature storage or oxygen free packing, while offering the consumer a longer shelf life. It therefore deserves to be supported by more formal arguments through accurate and quantified data from independent laboratories.
We therefore decided to organize, with the support of an external accredited laboratory a whole set of physicochemical tests as well as regular tasting sessions, the first of which will start in June 2017. First phase results will be available at the end of 2017 and the survey will run up to the end of 2018.
The study protocol includes measures of the peroxide index, FFA and hexanal, as well as bi-monthly tasting sessions. It will be conducted in parallel on different nut status :
• untreated (control samples) / untreated and reconditioned under vacuum
• roasted / roasted and reconditioned under vacuum
• Vacuum steam pasteurized by Steripure / vacuum steam pasteurized by Steripure and reconditioned under vacuum.