**1. Introduction**

Mayonnaise is semi-solid oil-in-water emulsion. Traditional mayonnaise is made from vegetable oil, egg yolk, vinegar, and spices during gentle mixing. Therefore, traditional mayonnaise as a high oil-containing product is susceptible to deterioration by fast, destructive oxidation of the unsaturated fats in its oil fraction. Oxidation processes reduce the nutritional value of fat-based products due to the loss of polyunsaturated lipids and vitamins that are beneficial to human health. However, the elimination of intrinsic (prooxidants content) and extrinsic factors (high temperature, light) and the addition of high-quality antioxidant ingredients can inhibit the oxidative reactions and increase the shelf life of mayonnaise [1]. On the other hand, mayonnaise ingredients, especially types of edible oils, fat replacers, and emulsifiers, strongly influence the physicochemical properties of the final products. Although the most common oils used to make mayonnaise are refined oils, such as rapeseed oil, sunflower oil, and soybean oil [2], the effect of various nut oils on the structure and physicochemical properties of gel-like emulsions was also investigated [3]. The gel-like emulsion with sunflower oil showed better stability than the gel-like emulsions of nuts oils due to the smaller particle size and higher viscosity. Moreover, mayonnaise made with linseed oil with a high level of linolenic acid (>50%) was more susceptible to

**Citation:** Włodarczyk, K.; Zienkiewicz, A.; Szydłowska-Czerniak, A. Radical Scavenging Activity and Physicochemical Properties of Aquafaba-Based Mayonnaises and Their Functional Ingredients. *Foods* **2022**, *11*, 1129. https://doi.org/10.3390/ foods11081129

Academic Editors: Marco Poiana, Francesco Caponio and Antonio Piga

Received: 15 March 2022 Accepted: 12 April 2022 Published: 14 April 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

lipid oxidation than mayonnaise with saturated medium-chain triglyceride oil [4]. However, Eidhin and O'Beirne [5] did not notice any changes in the oxidative stability of salad dressing and mayonnaises after the replacement of sunflower seed oil with refined camelina oil. In particular, many studies have reported that various cold-pressed oils (linseed, camelina, soybean, sunflower, rapeseed, corn, grapeseed, hemp, rice bran, pumpkin, walnut, rosehip, milk thistle, and black cumin) contain a higher level of natural antioxidants such as tocopherols (165.4–1036.0 mg/kg), phenols (5.1–1151.2 mg/kg), flavonoids (4.5–64.2 mg/kg), carotenoids (18.3–198.0 mg/kg), and squalene (0–1324.3 mg/kg) than refined vegetable oils [6–10]. Therefore, emulsions containing cold-pressed black cumin oil and cold-pressed rice bran oil had a better oxidative status (lower amounts of primary and secondary oxidation products) and antioxidant properties (higher total phenolics content and antioxidant potential determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) than control emulsions without cold-pressed oils [10,11].

Consequently, lipid oxidation in emulsions depends also on the type of emulsifier. It is well known that egg yolk is the most popular emulsifier used in traditional mayonnaise formulation. However, eggs consumption increases the risk of cardiovascular disease, particularly among diabetic patients [12–14], while today's consumers express greater concern about the quality and health benefits of eaten products. Lately, consumption of this product has decreased to promote environmental care and animal welfare. The mean daily water consumption footprint per capita in the European Union countries for eggs and egg products was approximately 1.5 times higher than this result for legumes, nuts, oilseeds and spices [15]. One other reason to reduce the consumption of eggs is an allergy caused by an allergic reaction to their proteins. Unfortunately, raw eggs present in mayonnaise are more likely to cause an allergic reaction than small amounts of cooked eggs. Egg allergy is one of the most common food allergies in infancy and small children, with a prevalence of up to 3.2% in the USA and Western Europe [16]. However, an allergy to eggs is rarely diagnosed in adults. Therefore, egg yolk in mayonnaise samples has often been replaced with plant protein isolates [17], canola protein [18], milk protein [19], soy milk [20], peanut and sesame meal milk [21], and Arabic gum [22]. Moreover, the effect of wastewater after cooking chickpeas (aquafaba) on the texture and physicochemical properties of plant-based mayonnaise was investigated [23]. Recently, the application of one of the most popular pulses cooking water (PCW)—aquafaba as a food ingredient has successfully broadened the list of new egg replacers [24]. Damian et al. [25] reported that PCW was a stable emulsifier and a rich source of phenolic compounds (0.3–0.7 mg/mL) and saponins (8–12 mg/mL). The amount of leached proteins and saponins impacted the foaming and gelling abilities of PCW. Other applications of aquafaba are in bakery products, dressing, dip, ice cream, legume-based cheese, and legume-based dairy substitutes [26]. Interestingly, chickpea ranks third among total legume production worldwide, after beans and peas and accounting for 10.1 million tons annually [27].

In recent years, the functional properties of aquafaba such as its emulsifying capacity, foaming ability, gelling attributed to its composition of proteins, carbohydrates, polysaccharide-protein complexes, coacervates, saponins, and phenolic compounds have been used in various formulations for vegans [28–30].

On the other hand, antioxidant compounds added to fat-based foods counteract lipid oxidation by acting as reducing agents, free radical scavengers and inactivators of prooxidants. Therefore, the antioxidant potential of emulsions enriched with new functional ingredients with antioxidant properties determines their quality and storage stability.

In this study, understanding the relationship between emulsion properties (mainly oxidative stability) and radical scavenging activity (RSA) is essential to improving the quality of mayonnaise production. To the best of our knowledge, there was no reference to the determination of the antioxidant properties of eggless mayonnaise containing aquafaba as a functional replacer. Therefore, the present work focused on the evaluation of radical scavenging characteristics, oxidation stability, microstructures, and optical properties of vegan mayonnaises containing aquafaba from chickpeas and blends of refined rapeseed

oil (RRO) with different cold-pressed oils as key ingredients. The radical scavenging and physicochemical properties of the prepared emulsions were characterized and compared with commercial samples (egg yolk-based and plant-based mayonnaises). The modified QUick, Easy, New, CHEap, and Reproducible (QUENCHER) procedure was applied for an evaluation of the RSA of mayonnaises, whereas the radical scavenging characteristics of ingredients were analyzed by two conventional 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods. Moreover, the emulsifying properties of aquafaba and fatty acid composition (FAC) of cold-pressed oils were estimated and discussed. Finally, a principal component analysis (PCA) was applied to check the differences and similarities among all of the studied mayonnaise samples.
