Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Water state and sugars in cranberry fruits subjected to combined treatments: Cutting, blanching and sonication Malgorzata Nowacka a , Luca Laghi b,c, ⁎ , Katarzyna Rybak a , Marco Dalla Rosa b,c , Dorota Witrowa-Rajchert a , Urszula Tylewicz b a Faculty of Food Sciences, Department of Food Engineering and Process Management, Warsaw University of Life Sciences (WULS-SGGW), Warsaw, Poland b Department of Agricultural and Food Sciences, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Cesena, Italy c Interdepartmental Centre for Agri-Food Industrial Research, Alma Mater Studiorum, University of Bologna, Campus of Food Science, Cesena, Italy ARTICLE INFO Keywords: Cranberries Ultrasound Cutting Blanching Water state TD-NMR ABSTRACT To ease the mass exchange in fruit tissues, cutting and blanching are traditionally performed. However, recently, unconventional methods such as sonication are becoming more popular, which cause several alterations of physical and chemical properties as well as microstructure changes. The aim of this work was to evaluate the distribution of water inside the cranberry fruits, microstructural changes and sugars content, following tradi- tional and sonication pre-treatments in osmotic solutions. TD-NMR spectroscopy was used to measure the transverse relaxation time (T 2 ) and intensity of proton pools in diferent cellular compartments. The micro- structure of the samples was evaluated by SEM microscopy, sugars content by HPLC and sucrose melting tem- perature and enthalpy by DSC. Diferent pre-treatments appeared to promote microstructure alterations and loss of water from vacuole and cytoplasm/extracellular space, more pronounced in cut and blanched samples. Cutting and blanching followed by osmotic dehydration with assisted sonication eased sucrose penetration into the tissue. 1. Introduction The use of ultrasound is one of the most promising treatment methods for food production processes as proved by scientifc and in- dustrial researches conducted currently on a large scale. Ultrasound is used for intensifcation of processes based on mass exchange such as drying (Musielak, Mierzwa, & Kroehnke, 2016; Witrowa-Rajchert, Wiktor, Sledz, & Nowacka, 2014), freezing (Cheng, Zhang, Xu, Adhikari, & Sun, 2015), osmotic dehydration (Nowacka, Tylewicz, et al., 2018) or extraction (Chemat et al., 2017). There are two main phenomena occurring during the sonication. The frst is called “sponge efect” and it occurs when the acoustic waves penetrate plant tissue and squeeze and release repeatedly the material. The second phenomenon is cavitation, the forming, growing and col- lapsing of gas bubbles, created by a sudden local increase in pressure and temperature in the material. Ultrasound application causes the formation of microscopic channels and the change in food properties (Miano, Ibarz, & Augusto, 2016; Pieczywek, Kozioł, Konopacka, Cybulska, & Zdunek, 2017; Wiktor, Sledz, Nowacka, Rybak, & Witrowa- Rajchert, 2016). The observations in this feld indicate that adapting properties and duration of the applied sound waves to the character- istics of the raw material, an optimization of the process could be ob- tained, in terms of shortening of required time and increase of mass exchange (Nowacka & Wedzik, 2016). Such optimization is far from straightforward, because it is linked on one side to the characteristics of the structure of the plant tissue, on the other side to the physical and chemical properties of fnal products (Fernandes, Gallão, & Rodrigues, 2008; Nowacka, Tylewicz, Laghi, Dalla Rosa, & Witrowa-Rajchert, 2014). In order to gain information able to drive the optimization of the process, time domain nuclear magnetic resonance (TD-NMR) represents a promising technique. Indeed, it has been extensively used on several fruits and vegetables (Dellarosa et al., 2016; Hills & Duce, 1990; Hills & Remigereau, 1997; Nowacka et al., 2014) to study the water redis- tribution through the structures of their pericarp, following dehydra- tion or treatments with ultrasound. By registering transverse relaxation time (T 2 ) weighted signals by means of CPMG pulses sequence (Meiboom, Gill, & Gillt, 1958), it is possible to separately observe three compartments: vacuole (V), with T 2 of nearly 1 s, cytoplasm plus ex- tracellular space (CE), with T 2 around 200 ms, and cell wall (W), with https://doi.org/10.1016/j.foodchem.2019.125122 Received 31 January 2019; Received in revised form 1 July 2019; Accepted 2 July 2019 ⁎ Corresponding author at: Department of Agricultural and Food Sciences, Alma Mater Studiorum, Università di Bologna, Campus of Food Science, Piazza Goidanich, 60, 47521 Cesena, Italy. E-mail address: l.laghi@unibo.it (L. Laghi). Food Chemistry 299 (2019) 125122 Available online 03 July 2019 0308-8146/ © 2019 Elsevier Ltd. All rights reserved. T