Impact of blanching and high hydrostatic pressure combined treatments on the physico-chemical and microbiological properties and bioactive-compound profile of an industrial strawberry smoothie

Abstract

Enhancing the shelf life of fruit and vegetable products is an important research field in the food industry. Smoothies are an alternative to filtered juices and highly processed beverages. High-pressure processing (HPP) has recently gained increasing attention as a non-thermal technology to reduce microbiological load while preserving juice quality-related properties. Herein, the combination of blanching and HPP to treat strawberry smoothies at industrial scale was compared with conventional thermally pasteurized (TP) and untreated (NT) smoothies. Analysis focused on physicochemical (pH, °Brix, colour, and viscosity) and microbiological properties, and bioactive compound contents. Additionally, phenolic compounds were analysed by HPLC-ESI-TOF-MS, vitamin C content was analysed by HPLC-UV-Vis, and antioxidant activity was determined by DPPH and ABTS assays. HPP samples treated at 600 MPa for 3 min at 4 °C showed increased viscosity and a significant increase in phenolic compounds (particularly p-coumaroyl hexose) related to TP and untreated samples (26.8 and 17.6%, respectively) and maintained colour stability compared to untreated samples. Anthocyanidins retention was better in HPP- than in TP- treated samples. Vitamin C content increased significantly by 15% in HPP-treated samples, contributing to enhanced antioxidant potential (12%), as shown by the minimal microbiological load observed, in comparison with untreated samples. These findings suggest that HPP is an effective alternative to TP for improving the overall quality of strawberry smoothies.