**Abstract**

Adverse reactions to food such as allergies and celiac disease are increasingly recognized as a growing public health burden. There is currently no cure for these diseases so that there is an unmet need to evaluate different nutritional approaches aiming at improving the quality of life of affected patients and their families. In this context, healthy promising nature-derived compounds, most of which contained in fruits and vegetables, have been studied as an alternative to attenuate the epidemic. Indeed, phenolic compounds have become an emerging field of interest in nutrition in the last decades. A growing build of research suggests that phenolic compounds inhibit pro-inflammatory transcription factors by interacting with proteins involved in gene expression and cell signaling, leading to protective effects against many inflammation-mediated chronic diseases. However, the use of phenolic compounds as attenuating agents of immune reactions to food has to be aligned to the organoleptic characteristics of food, since many compounds present unpleasant taste properties, namely bitter taste and astringency. In this framework, tasty but healthy phenolic compounds arise as attractive ingredients in the design and formulation of functional foods. This book chapter is focused on revisiting the organoleptic properties of phenolic compounds while evaluating the role of these compounds in health promoting actions, namely the management of immune reactions to food such as Food Allergies and Celiac Disease.

**Keywords:** food allergies, celiac disease, functional foods, phenolic compounds, clean label

## **1. Introduction**

"Healthy" and "natural" are two keywords appealing for consumers. Along with these, there is a growing demand for "functional" and "clean label" food products. The food system and consumers demand for new functional products that have potentially positive effects on health besides basic nutrition alongside to products made with few ingredients, preferably natural ones and assuring that these new ingredients are easy-to-recognize. In fact, "clean label" is a new "action" of food system to recover consumer trust, somehow lost in the past decades due to different issues, such as low transparency about ingredients. The term clean label is complex and multidimensional. While there is not a specific definition of the term, it is

while accepted that clean label refers to "natural" food, with simple, well-known and short ingredients list while avoiding the use of synthetic additives [1, 2]. In this context, the use of natural extracts rich in bioactive compounds able to reduce the use of synthetic additives arise as a new reality. Consumers' of nowadays are more informed and demanding. In addition, to healthy, functional and natural, consumers are also demanding for sustainable food products. Within this framework, plantbased ingredients and bioactive compounds arise as promising tools because they comprise all these topics. This chapter will focus on a class of plant-based bioactive compounds, the phenolic compounds, and their potential to be added to functional and clean labelfoods. This chapter will start by covering the structural classification and occurrence of phenolic compounds, their health bioactivities as well as their potential application for modulation of immune reactions to food (food allergies and celiac disease). While these compounds are undoubtedly healthy, their supplementation in food can affect the sensory properties leading to unpleasant effects, namely bitter taste and astringency perception. This will be also focused inside this chapter. The technological properties of phenolic compound as new ingredients will be also discussed considering the interactions within food matrices. Despite their importance, these interactions are usually overlooked in functional and clean label foods. At the end, this chapter aims to highlight that functional foods should constitute a part of a healthy but tasteful diet.
