**1. Introduction**

In recent years, new perspectives for oilseed crops have revealed them to be renewable and valuable feedstocks for biorefinery processes, responding to the urgent need to transition toward a circular economy model based on the zero-waste concept [1]. These crops, in fact, are particularly suitable for obtaining, through a cascading use of total biomass, highest added-value products (pharmaceuticals, nutraceuticals, fine chemicals, cosmetics, agrochemicals, biomaterials), over bioenergy. In particular, oilseed meals and cakes, deriving from seed oil extraction, represent interesting co-products due to their high protein content, also for the presence of bioactive substances, such as phenolic acids, flavonoids, lignans and other antioxidant compounds [2], which could be used as food additives, supplements or cosmeceutical additives for foods and human health protection. In addition to the main oilseed crops, such as soybean and rapeseed used for food, feed and biofuel production, there is a growing interest in other minor oilseed crops suitable for marginal land, which could have a positive impact on the sustainability and resilience of agroecosystems. In this

**Citation:** Tavarini, S.; De Leo, M.; Matteo, R.; Lazzeri, L.; Braca, A.; Angelini, L.G. Flaxseed and Camelina Meals as Potential Sources of Health-Beneficial Compounds. *Plants* **2021**, *10*, 156. https://doi.org/ 10.3390/plants10010156

Received: 23 December 2020 Accepted: 12 January 2021 Published: 14 January 2021

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**Copyright:** © 2021 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/).

contest, flaxseed (*Linum usitatissimum* L., family Linaceae) and camelina (*Camelina sativa* (L.) Crantz, family Brassicaceae) are becoming more and more important in the health food market as a functional food and cosmetic ingredients [3,4]. Both crops, compared to the traditional oilseeds, display several agronomic advantages, such as great adaptability and phenotypic plasticity, low water and nutrient requirements, as well as good tolerance to pests and pathogens [5,6]. These positive agronomic attributes make these oilseed crops promising to be introduced in Mediterranean agroecosystems, where they might represent useful tools for enhancing biodiversity and cropping system diversification. These crops are not only characterized by positive agronomic traits, but they also have interesting chemical and functional features due to their products and co-products compositions. The nutritional importance of flaxseed is due to the high content of proteins (22%), lipids (43%) and minerals (3%). Its oil represents an important source of omega-3 fatty acids, especially linolenic acid (ALA) (more than 50% of the total fatty acids) [7]. Furthermore, flaxseed seeds, oil and cake are the richest source of the lignan secoisolariciresinol diglucoside (SDG), a natural cancer chemopreventive agent [8], in form of high molecular oligomers. At the same time, the high potential of camelina for nutritional applications is attributed to the distinctive fatty acid composition of its oil, rich in alpha-linolenic (18:3) and linoleic (18:2) acids [9,10]. Being an essential omega-3, alpha-linolenic acid has beneficial health effects on humans [11]. The presence of eicosenoic acid (11–19%) and tocopherols in relatively large amounts, and the low content of anti-nutritionals such as erucic acid, are additional distinctive differences of camelina in comparison with other commonly used vegetable oils [9,12]. All these compounds have antioxidant and free-radical scavenging activities and can play an important role in preventing several human diseases thanks their potential anti-tumoral, antiviral, antibacterial, and anti-mutagenic abilities [13]. For the aforementioned properties, flaxseed and camelina meals have interesting usable potential as ingredients for food and non-food purposes. Cake/meals composition is known to have a wide range of variability, depending on genetic and environmental growing conditions, and the extraction method. However, the current state of knowledge about the chemical composition of camelina and flaxseed meals, depending on the variety/cultivar and environmental conditions in which the plant is grown, is scarce. Therefore, the present study aimed to evaluate the role of environment and genotype in defining the chemical features of flaxseed and camelina meals. Consequently, the seed meals, obtained after solvent oil extraction, deriving from two flaxseed varieties (Sideral and Buenos Aires) and a camelina cultivar (Italia), cultivated in two environments of central and northern Italy (Pisa and Bologna), were analyzed for their phytochemical content and tested for their radical-scavenging activity. At the same time, the seed yield, oil and protein content and oil yield as well as fatty acid profile, were investigated for all the tested varieties in both environments, providing useful information about camelina and flaxseed yield potential under the climate conditions of Mediterranean region.
