Shelf‐life extension of multi‐vegetables smoothies by high‐pressure processing compared with thermal treatment. Part I: Microbial and enzyme inhibition, antioxidant status, and physical stability

• Published in: Journal of food processing and preservation 2019-10, Vol.43 (10), p.1-n/a
• Main Authors: Hurtado, Adriana, Dolors Guàrdia, Maria, Picouet, Pierre, Jofré, Anna, Bañón, Sancho, Ros, José María
• Format: Article
• Language: English
• Subjects: Humanities and Social Sciences; Life Sciences
• ISSN: 0145-8892; 1745-4549
• DOI: 10.1111/jfpp.14139

Consumer demand for minimally processed food products based on fruits and vegetables is associated with their “fresh‐like” qualities and a desire for convenience. Smoothies could help meet these needs and contribute to increasing fruit and vegetable intake. The first part of this study assesses microbial and enzyme inactivation, antioxidant status, and physical stability of a vegetable smoothie (apple, carrot, zucchini, pumpkin, and leek) stabilized (for up to 28 days at 4°C) by high‐pressure processing (HPP) (350 MPa/5 min/10°C). Compared with mild heating (85°C/7 min), HPP ensured microbial quality (aerobic mesophilic and psychotropic bacteria, yeasts and molds), inhibited peroxidase, and slightly enhanced polyphenol oxidase and pectinmethylesterase enzymes. Consequently, the pressurized smoothies underwent earlier clarification and oxidation as reflected in their values of turbidity, browning index, viscosity, and antioxidant capacity. Therefore, the pressurizing conditions and/or raw material selection need to be improved to achieve better stabilization by HPP. Practical applications High‐pressure processing (HPP) allows fresh‐like vegetable smoothies to be obtained with an extended shelf‐life from the microbiological point of view. A handicap for industry is to choose the pressurization conditions able to maintain vegetable smoothies stable during a suitably long shelf time, without altering other properties of interest. This requires establishing pressurization patterns more adapted to the properties (enzyme activities, antioxidant status, color, viscosity, turbidity, etc.) of the raw materials used in the homogenates.