The aim of this study was to evaluate changes in quality attributes of non‐clarified strawberry juice during storage at 5 °C after ultrasonication at 40 kHz for 10 and 30 min in comparison with thermally treated juice at 90 °C for 60 s. Ultrasound treatments maintained color parameters with no significant differences (p < .05) from untreated sample, while thermally treated juice showed lower L* values and higher hue angles than the control. No significant differences in °Brix and total acidity were found between treated and untreated samples, and both parameters remained unchanged throughout storage. Compared to the control, ultrasound treatments showed no significant reductions on day 0 in mesophilic and psychrophilic bacteria, and yeast and molds counts. However, the treatments showed significant decrease in the microbial growth rate through storage time, and significant increase in both polyphenol content and antioxidant activity, compared to control. Practical applications With today's tendency towards the consumption of nutritious and fresh‐like foods, non‐thermal treatments are gaining popularity. Among them, ultrasound has become a feasible alternative against traditional thermal treatments. Strawberry products are considered of great nutritional value, because of their high content in antioxidant compounds and vitamin C. In this study, ultrasound was evaluated in strawberry juice through storage time, where significant reductions on microbial growth rate were achieved; meaning that shelf‐life of the product was increased compared to control. Furthermore, physicochemical parameters were maintained through storage, and antioxidant capacity and polyphenol content showed a significant increment, which implies that nutritional value of the product was increased by ultrasound treatments. Therefore, sonication is a potential technology that can easily be applied at the fruit juice industry, replacing the traditional thermal treatment which compromises the organoleptical and nutritional quality of the final product.

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Lettuce (Lactuca sativa) is one of the most popular leafy vegetables in the world and constitutes a major dietary source of phenolic compounds with health-promoting properties. In particular, the demand for green and red oak-leaf lettuces has considerably increased in the last years but few data on their polyphenol composition are available. Moreover, the usage of analytical edge technology can provide new structural information and allow the identification of unknown polyphenols. In the present study, the phenolic profiles of green and red oak-leaf lettuce cultivars were exhaustively characterized by ultrahigh-performance liquid chromatography (UHPLC) coupled online to diode array detection (DAD), electrospray ionization (ESI), and quadrupole time-of-flight mass spectrometry (QToF/MS), using the MS instrument acquisition mode for recording simultaneously exact masses of precursor and fragment ions. One hundred fifteen phenolic compounds were identified in the acidified hydromethanolic extract of freeze-dried lettuce leaves. Forty-eight of these compounds were tentatively identified for the first time in lettuce, and only 20 of them have been previously reported in oak-leaf lettuce cultivars in literature. Both oak-leaf lettuce cultivars presented similar phenolic composition, except for apigenin-glucuronide and dihydroxybenzoic acid, only detected in the green cultivar; and for luteolin-hydroxymalonylhexoside, an apigenin conjugate with molecular formula C H O (monoisotopic MW = 838.3259 u), cyanidin-3-O-glucoside, cyanidin-3-O-(3″-O-malonyl)glucoside, cyanidin-3-O-(6″-O-malonyl)glucoside, and cyanidin-3-O-(6″-O-acetyl)glucoside, only found in the red cultivar. The UHPLC-DAD-ESI-QToF/MS approach demonstrated to be a useful tool for the characterization of phenolic compounds in complex plant matrices.