Assessment of Protein Nutritional Quality of Novel Hairless Canary Seed in Comparison to Wheat and Oat Using In Vitro Static Digestion Models.

Hairless canary seed (Phalaris canariensis L.) is a novel true cereal that is now approved for human consumption in Canada and the United States. This true cereal grain has higher protein content (22%) than oat (13%) and wheat (16%) and represents a valuable source of plant proteins. Assessment of canary seed protein quality is therefore essential to evaluate its digestibility and ability to provide sufficient amounts of essential amino acids for human requirements. In this study, the protein nutritional quality of four hairless canary seed varieties (two brown and two yellow) were evaluated in comparison to oat and wheat. The assessment of anti-nutrients contents (phytate, trypsin inhibitor activity, and polyphenols) showed that brown canary seed varieties had the highest content in phytate and oat the highest in polyphenols. Trypsin inhibitor level was comparable among studied cereals, but slightly higher in the brown canary seed Calvi variety. In regard to protein quality, canary seed had a well-balanced amino acid profile and was particularly high in tryptophan, an essential amino acid normally lacking in cereals. The in vitro protein digestibility of canary seeds as determined by both the pH-drop and INFOGEST (international network of excellence on the fate of food in the gastrointestinal tract) protocols appears slightly lower than wheat and higher than oat. The yellow canary seed varieties showed better overall digestibility than the brown ones. For all studied cereal flours, the limiting amino acid was lysine. The calculated in vitro PDCAAS (protein digestibility corrected amino acid score) and DIAAS (digestible indispensable amino acid score) were higher for the yellow C05041 cultivar than the brown Bastia, similar to those of wheat, but lower than those of oat proteins. This study demonstrates the feasibility and utility of in vitro human digestion models for the assessment of protein quality for comparison purpose.

Scale up fractionation of components from novel glabrous brown and yellow canary seeds (Phalaris canariensis L.) and techno-functional properties of the resulting protein isolates.

Glabrous canary seed (Phalaris canariensis L.) is a novel true cereal grain produced primarily in Western Canada which has been approved for human consumption by the U.S. Food and Drug Administration and Health Canada in 2016. Due to its high protein content (22%), this new edible grain is emerging as an alternative source of plant proteins. In the present work, protein extractability from four novel glabrous (2 yellow and 2 brown) canary seeds varieties was improved based on the selection of optimal pH of protein solubilisation and precipitation. Solubilisation at pH 12 followed by acid precipitation at pH 5 were retained as optimal conditions. Scale up of the protein optimized wet fractionation process resulted in highly purified canary seed protein isolates (purity of 91 to 93%) with protein recovery yield of 65 to 69%. In parallel, for the others canary seed components, a good recovery yields were obtained for the oil fraction (6.1-6.7 g/100 g flour), starch fraction (48.1-54 g/100 g flour), and crude fiber fraction (15.1-19.7 g/100 g flour). The study of the functional properties of the obtained canary protein isolates revealed, higher solubility at acidic than alkaline region; enhanced fat and water holding capacities and notably higher foaming and emulsifying capacities than control soy protein isolate. With growing global demand for protein, glabrous canary seed has high potential in the food industry, particularly as a good source of functional gluten free cereal proteins.

Consensus-degenerate hybrid oligonucleotide primers for amplification of priming glycosyltransferase genes of the exopolysaccharide locus in strains of the Lactobacillus casei group.

A primer design strategy named CODEHOP (consensus-degenerate hybrid oligonucleotide primer) for amplification of distantly related sequences was used to detect the priming glycosyltransferase (GT) gene in strains of the Lactobacillus casei group. Each hybrid primer consisted of a short 3' degenerate core based on four highly conserved amino acids and a longer 5' consensus clamp region based on six sequences of the priming GT gene products from exopolysaccharide (EPS)-producing bacteria. The hybrid primers were used to detect the priming GT gene of 44 commercial isolates and reference strains of Lactobacillus rhamnosus, L. casei, Lactobacillus zeae, and Streptococcus thermophilus. The priming GT gene was detected in the genome of both non-EPS-producing (EPS(-)) and EPS-producing (EPS(+)) strains of L. rhamnosus. The sequences of the cloned PCR products were similar to those of the priming GT gene of various gram-negative and gram-positive EPS(+) bacteria. Specific primers designed from the L. rhamnosus RW-9595M GT gene were used to sequence the end of the priming GT gene in selected EPS(+) strains of L. rhamnosus. Phylogenetic analysis revealed that Lactobacillus spp. form a distinctive group apart from other lactic acid bacteria for which GT genes have been characterized to date. Moreover, the sequences show a divergence existing among strains of L. rhamnosus with respect to the terminal region of the priming GT gene. Thus, the PCR approach with consensus-degenerate hybrid primers designed with CODEHOP is a practical approach for the detection of similar genes containing conserved motifs in different bacterial genomes.