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The sensory, microbial and bioactive quality changes of untreated (CTRL) and mild heat−treated (HT; 90 ºC/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 ºC). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelf−life (CTRL/HT) of 18/55 (at 5 ºC), 4.5/12 (at 15 ºC), 2.4/5.8 (at 25 ºC) days. The yeast and moulds growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HT−5/15 ºC. HT and 5 ºC−storage stabilized the phenolics content. FRAP reported the best correlation (R2=0.94) with the studied bioactive compounds, followed by ABTS (R2=0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R2=0.49). Conclusively, modelling was used to estimate the shelf−life of a smoothie based on quality retention after a short time−high temperature heat treatment that better preserved microbial and nutritional quality during storage.

Carrots are worldwide highly consumed due to their sensory characteristics and health-promoting properties. However, their low phenolic/antioxidant levels may be greatly increased with abiotic stresses. Accordingly, phenolic/antioxidant enhancements and related phenylalanine ammonia-lyase (PAL) activity of carrot shreds under different treatments (UVc radiation and hyperoxia conditions) were studied after a pre-enrichment incubation of 72 h at 15ºC. Subsequently, a carrot smoothie prepared from enriched carrot shreds was heat-treated (90ºC for 30 s) and stored at 5ºC up to 14 days. Heat-treated smoothies showed a good physicochemical and microbiological quality (<6 log CFU g-1) after 14 days at 5ºC, although those non-irradiated samples registered lower psychrophilic and yeasts and molds levels. Heat-treated smoothie from non- irradiated shreds stored under hyperoxia conditions, showed the highest total phenolic content of 13,82 mg ChAE kg-1 fw (87 % chlorogenic acid) after 14 days at 5ºC. Total phenolics content was in accordance with PAL and total antioxidant capacity. Conclusively, a pre-enrichment incubation of carrot shreds under hyperoxia conditions allowed to obtain a functional smoothie with great phenolic levels and good microbiological and physicochemical quality up to 14 days at 5ºC.