Food Research International 137 (2020) 109676 Available online 17 September 2020 0963-9969/© 2020 Elsevier Ltd. All rights reserved. Review Seaweed-based natural ingredients: Stability of phlorotannins during extraction, storage, passage through the gastrointestinal tract and potential incorporation into functional foods Lucia Cassani a, b, * , Andrea Gomez-Zavaglia b, c , Cecilia Jimenez-Lopez d, e , Catarina Lourenço-Lopes d , Miguel A. Prieto d , Jesus Simal-Gandara d a Research Group of Food Engineering, Faculty of Engineering, National University of Mar del Plata, RA7600 Mar del Plata, Argentina b Consejo Nacional de Investigaciones Científcas y T´ ecnicas (CONICET), Argentina c Center for Research and Development in Food Cryotechnology (CIDCA, CCT-CONICET La Plata), RA1900 La Plata, Argentina d Nutrition and Bromatology Group, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E32004 Ourense, Spain e Centro de Investigaç˜ ao de Montanha (CIMO), Instituto Polit´ ecnico de Bragança, Campus de Santa Apolonia, 5300-253 Bragança, Portugal A R T I C L E INFO Keywords: Health-related compounds Renewable resources Bioavailability Extraction and stabilization approaches Natural plant-derived ingredients ABSTRACT Adding value to seaweed by extracting their different bioactive compounds and incorporating them into foods represent an interesting and strategic approach to diversify the functional foods offer. However, once harvested, fresh seaweed must overcome a sequence of crucial steps to confer their biological activity. Pre-processing op- erations and extraction processes, as well as long-term storage, play important roles in improving or decreasing the phlorotannins content. In their way to the gut (biological target), phlorotannins are exposed to the human gastrointestinal tract (GIT), where the physiological pH and digestive enzymes can signifcantly affect the phlorotannins’ stability and thus, alter their biological activity. Besides, the subsequent incorporation into foodstuffs could be limited due to sensory issues, as tannins have been associated with astringency and bitter taste, and thus effective phlorotannins doses may negatively affect the sensory attributes of foods. These drawbacks expose the need of applying smart strategies to develop a fnal product providing the necessary protective mechanisms to maintain the active molecular form of phlorotannins up to the consumption time, also controlling their release upon arrival to the gut. In this context, the impact of these technological processes (from pre-processing to the passage through the GIT) on phlorotannins stability, as well as the innovative developed approaches to overcome these issues will be deeply discussed in this review. Besides, recent fndings related to the phlorotannins’ health benefts will be pointed out. Special attention on the potential incorporation of phlorotannins into functional foods will be also put it on. 1. Introduction The concept of nutrition has progressively evolved over the last few years. Indeed, food is not only considered as a nutritional source of compounds to prevent energetic defciencies but also as a rich source of bioactive compounds that have demonstrated to play an important role in health promotion and prevention of chronic diseases (Gupta & Abu- Ghannam, 2011). In particular, algae have gained attention as rich sources of under-exploited bioactive compounds, potentially useful as novel functional ingredients (Li & Kim, 2011; Plaza, Cifuentes, & Ib´ a˜ nez, 2008). According to Ferdouse, Holdt, Smith, Murua, and Yang (2018), the global seaweed market is continuously growing in terms of value and volume because of the increasing demand of the food industry. Considering that the annual growth rate is about 10%, it is expected that the total value would increase up to USD 26 million by 2025 (Ferdouse et al., 2018). Despite being a millionaire industry, the global seaweed production is still limited to the cultivation of edible species [e.g., more than 90% of Japanese farms cultivate nori (Porphyra spp.), kombu (Saccharina japonica) and wakame (Undaria spp.)] and to the phyco- colloids industry (e.g., agar-agar, carrageenan, and alginate extracts) (Ferdouse et al., 2018; Kadam, Tiwari, & O’Donnell, 2013). For this * Corresponding author at: Research Group of Food Engineering, Faculty of Engineering, National University of Mar del Plata, RA7600 Mar del Plata, Argentina. E-mail address: lcassani@f.mdp.edu.ar (L. Cassani). Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres https://doi.org/10.1016/j.foodres.2020.109676 Received 21 April 2020; Received in revised form 3 August 2020; Accepted 6 September 2020