Quality preservation and safety ensurement of a vegetable smoothie by high-pressure processing

摘要

This research aims to evaluate the effect of a previously optimized high-pressureprocessing (HPP) treatment on the vegetable smoothie stability during 28 days at5 ℃ and on the inactivation of a contamination with Listeria monocytogenes andEscherichia coli O157:H7 surrogates during 12 days at 15 ℃. HPP (630 MPa/6 min)reduced native microbiota to values below detection limit (DL = 1 log CFU/g) andsignificantly reduced polyphenol oxidase, peroxidase, and pectin methylesterase initialactivities (16.7%, 29.6%, and 70.7%, respectively), maintaining significant lowervalues than control during storage. In addition, smoothie's soluble solids and pH wereneither modified with treatment nor storage time, while greater retention of colorand nutritional indicators was noted on treated samples during storage. Moreover,HPP allowed controlling 6 log CFU/g surrogate counts, maintaining them below DLduring storage. Hence, optimized HPP treatment is effective to improve the qualitystability of the product besides ensuring their safety when contamination occurs.Practical applicationsHigh-pressure processing is an alternative preservation method that not only is effectivefor microbial and enzymatic control but also has demonstrated promisingresults in antioxidant and bioactive compounds preservation, which is of especialrelevance in foods such as fruit and vegetable smoothies that contain large amountof them. Recently, smoothies have gained strength in the market as part of the trendtoward healthy eating habits. However, there is little information available on the effectof conservation technologies on this type of matrix. This is one of the first studiesaddressing the effect of high hydrostatic pressure processing during the storageof mixed fruit and vegetable smoothies, providing information of great interest for anindustry in full growth.