Introduction

Interest in industrial oilseed crops dedicated to liquid biofuel production has been successful in bringing Camelina sativa (L.) Crantz, (camelina), commonly known as false flax or linseed dodder, to the Canadian prairies. Camelina, a member of the Brassicaceaefamily, produces seed containing three valuable biopolymers – oil (36-43%), protein (20-33%) and fibre (10-13%) – with mucilageneous polysaccharides of the seed coat comprising 6-10% of the seed weight and contributing to the soluble fibre fraction (Zubr 2010; Li et al., 2016; Zhu et al., 2016). Camelina oil is generally destined for liquid biofuels; however, the high omega-3 fatty acid content (30-40% α-linolenic acid) makes it suitable for use in human food applications and as a replacement for fish oil in aquaculture feed. Camelina meal, what remains after oil extraction, contains ~40-45% protein (Boyle et al., 2018; Li et al., 2014) and fibre, including polysaccharides. Transcriptome analysis of developing seeds showed that the seed storage proteins (SSPs) of camelina resemble those of otherBrassicaceae species and primarily consist of cruciferin and napin (Nguyen et al., 2013). According to Russo and Reggiani (2015), a rapid and steady increase in camelina SSP (cruciferin and napin) occurs seven days after pollination and ends at around 42 days after pollination. Nutritional and techno-functional properties of camelina meal protein products relevant in plant-protein-based applications have been reported by few researchers (Boyle et al., 2018; Kim and Netravali, 2012: Li et al., 2014). Camelina meal contains glucosinolates, namely, glucoarabin [9-(methylsulfinyl)nonylglucosinolate], glucocamelin [(10-(methylsulfinyl)decylglucosinolate)], and 11-(methylsulfinylundecylglucosinolate), at levels of 9-36 μmols/g seed (Matthaus and Zubr, 2000; Schuster and Friedt, 1998). In the context of the bioeconomy, almost all of these components of camelina seed have economic value that can be valorized.
Archeological and historical evidence indicate that camelina was cultivated in Europe since the Bronze Age (Zubr, 1997). Sustainable production of camelina on marginal lands has been proven however, establishment of camelina as a financially competitive, contemporary, oilseed crop necessitates extraction and valorization of both the oil and meal co-products. In the current market, utilization of camelina protein requires nutritional, techno-functional, and safety evaluation. Information on the types of camelina SSPs proteins, and their their structural and physico-chemical properties is limited. SSPs of the widely-cultivated crucifer, canola/rapeseed (Brassica napus ), primarily consist of 11S cruciferin, a cupin family protein, and 2S napin, a prolamin family protein, each with distinct structural and physico-chemical properties that bring diverse end-use opportunities as a plant protein (Perera et al., 2016; Wanasundara, 2011; Wanasundara and McIntosh, 2013). Information on the genetic, chemical and physico-chemical details of camelina seed protein will fill this knowledge gap and optimize their utilization. This study investigated the types of proteins present in camelina meal, and the structural characteristics and physico-chemical properties of the major camelina SSPs.