Optimization of high pressure processing parameters to preserve quality attributes of a mixed fruit and vegetable smoothie

Fruit & Vegetable (F&V) smoothies are rich in nutrients and other health related compounds. However, they have a short shelf-life and the traditional methods applied to preserve them generate losses in their natural flavor and nutrients. The aim of this study was to optimize the pressure level (35-650 MPa) and holding time (1-9 min) of High Pressure Processing (HPP), performed at an initial temperature of 20 degrees C and only modified by adiabatic heating of a F&V smoothie in order to achieve microbial and enzymatic inactivation while maintaining its natural attributes. Response surface methodology with a Doehlert design and Desirability function were employed to simultaneously optimize these quality attributes. Results showed that HPP enhances microbial quality and does not affect pH, total soluble solids, texture and total phenolic content. Moreover, the optimal HPP treatment (627.5 MPa/6.4 min) leads to reductions of 85%, 45% and 10% on PME, POD and PPO, increases antioxidant capacity by 75% and maintains or slightly improves the color of the smoothie. Industrial relevance text F&V smoothies are tasty, healthy, convenient and ready to drink, fulfilling all the current demands of consumers. This has led to an accelerated increase in their popularity. However, they have a short shelf life mainly attributed to microbial and enzymatic spoilages. HPP is proposed as a non-thermal method able to prolong shelf-life of the products by means of microbial and enzymatic inactivation, while preserving bioactive compounds and quality characteristics. An optimization assay was carried out in order to find optimal process conditions for the F&V smoothie's preservation. The promising results obtained can help to promote the use of HPP as an alternative technology for the preservation of this kind of products.