Polyphenols: A Comprehensive Review of their Nutritional Properties

Abstract

Polyphenols are the most prominent natural antioxidants found numerously in nature. They are secondary metabolites recognized for having high health benefits for consumers, even if the exploitation of these remarkable natural compounds is still a challenge. Moreover, there is a dilemma over the nutritional value of polyphenols. Hence, this paper seeks to review the classification, sources, anti-browning effect, antioxidant activity, nutritional property and anti-disease effect of polyphenols for better understanding the issues which need to be addressed in the valorization of these natural compounds.

Environmentally Friendly Techniques for the Recovery of Polyphenols from Food By-Products and Their Impact on Polyphenol Oxidase: A Critical Review

“…The enzymatic browning happens after the breakdown of cell structure, and the subsequent interaction between PPO and polyphenols causes color change and a reduction in the antioxidant activity, leading to the deterioration of food nutritional properties [132]. In addition, the reaction between PPO and polyphenols give rise to their oxidation resulting in a decrease in TPC, which has a negative impact in the extraction process of polyphenols from food by-products [21]. Therefore, it is crucial to find an appropriate solution to reduce the drawbacks derived from PPO and prevent the oxidation of polyphenols during the extraction process.…”

“…Application of nonthermal technologies in the extraction of polyphenols may have different results for the enzymatic activity because they influence PPO by several factors, including the intensity, duration, mode of exposure, gas composition, electrical input, and degradation of enzymes or substrates [134]. Nonthermal techniques decrease the amount of PPO, resulting in the better maintenance of phenolic compounds [21]. Indeed, the reduction of PPO activity has a direct impact on the maintenance of polyphenols and could increase the recovery yield of polyphenols [28,132,135,136].…”

“…These compounds are a group of secondary metabolites derived from phenylalanine, and they own one or more phenolic rings with one or several bound hydroxyl groups. Polyphenols act as natural antioxidants, enhancing the nutritional value of food by retarding the oxidation of lipids [8,21,22]. To date, many studies have classified polyphenols as nutritional sources possessing a highly beneficial impact on the prevention of many diseases, including diabetes, obesity, atherosclerosis, hyperlipidemia, hypertension, Alzheimer's, and thrombosis [21,23].…”

“…Polyphenols act as natural antioxidants, enhancing the nutritional value of food by retarding the oxidation of lipids [8,21,22]. To date, many studies have classified polyphenols as nutritional sources possessing a highly beneficial impact on the prevention of many diseases, including diabetes, obesity, atherosclerosis, hyperlipidemia, hypertension, Alzheimer's, and thrombosis [21,23]. Therefore, it is crucial to recover these compounds from herbal food wastes and use them also in the production of functional foods and ingredients.…”

The α-Amylase and α-Glucosidase Inhibition Capacity of Grape Pomace: A Review

“…Phenolic compounds are found in most plants and more than 10,000 structures have been detected so far (Alqahtani et al, 2013). Their great potentials as powerful bioactive compounds, health-promoting, and disease-preventing have increased the interest in these secondary metabolites in recent years (Ebrahimi & Lante, 2021;Tan & Chang, 2017). The content of phenolic compounds and their composition rely on the growth region, climate, and grape variety, among other factors related to the winemaking process (Muñoz-Bernal et al, 2021).…”