Katariina Rommi

Effect of Enzyme-Aided Cell Wall Disintegration on Protein Extractability from Intact and Dehulled Rapeseed (Brassica rapa L. and Brassica napus L.) Press Cakes

Cell-wall- and pectin-degrading enzyme preparations were used to enhance extractability of proteins from rapeseed press cake. Rapeseed press cakes from cold pressing of intact Brassica rapa and partially dehulled Brassica napus seeds, containing 36-40% protein and 35% carbohydrates, were treated with pectinolytic (Pectinex Ultra SP-L), xylanolytic (Depol 740L), and cellulolytic (Celluclast 1.5L) enzyme preparations. Pectinex caused effective disintegration of embryonic cell walls through hydrolysis of pectic polysaccharides and glucans and increased protein extraction by up to 1.7-fold in comparison to treatment without enzyme addition. Accordingly, 56% and 74% of the total protein in the intact and dehulled press cakes was extracted. Light microscopy of the press cakes suggested the presence of pectins colocalized with proteins inside the embryo cells. Hydrolysis of these intracellular pectins and deconstruction of embryonic cell walls during Pectinex treatment were concluded to relate with enhanced protein release.

Impact of Total Solid Content and Extraction pH on Enzyme-Aided Recovery of Protein from Defatted Rapeseed (Brassica rapa L.) Press Cake and Physicochemical Properties of the Protein Fractions

Pectinase treatment was used to facilitate protein recovery from defatted rapeseed (Brassica rapa) cold-pressing residue in water-lean conditions and without pH adjustment. Effect of extraction pH on protein yield and physiochemical properties of the protein concentrates was assessed. Enzymatic hydrolysis of carbohydrates was feasible at high (40%) solid content and improved protein recovery at pH 6. Comparable protein yields (40-41% of total protein) from enzyme-aided water extraction (pH 6) and nonenzymatic alkaline extraction (pH10) at 10% solid content suggested that after enzymatic treatment, rapeseed protein could be extracted without exposure to alkali. However, water extraction required dilute conditions, whereas alkaline extraction was feasible also at 20% solid content. The water extracts possessed better protein solubility, higher ζ-potential, and smaller particle size than isoelectric precipitates from alkaline extraction, indicating higher dispersion stability. This is suggested to be mediated by electrostatic interactions between proteins and pectic carbohydrates in the water extracts.

Bioactivities of fish protein hydrolysates from defatted salmon backbones

Graphical abstract

Biocompounds from rapeseed oil industry co-stream as active ingredients for skin care applications

Despite the great number of substances produced by the skincare industry, very few of them seem to truly have an effect on the skin. Therefore, given the social implications surrounding physical appearance, the search for new bioactive compounds to prevent or attenuate skin ageing and enhance self‐image is a priority of current research. In this context, being rich in valuable compounds, such as proteins, phenolics, lipids and vitamins, this study is focused on the potential activity of rapeseed press cake hydrolysates to be used as raw materials for skincare applications.

Biochemical and sensory characteristics of the cricket and mealworm fractions from supercritical carbon dioxide extraction and air classification

Insects represent a sustainable but under-exploited food resource partly due to the chitin-containing exoskeleton and also the high lipid content that hamper the production of food ingredients. Here we present dry fractionation technology for upgrading house crickets (Acheta domesticus) and yellow mealworm larvae (Tenebrio molitor) by extraction with supercritical carbon dioxide followed by separation to fine and coarse fractions by air classification. The defatted insects contained 73–79% crude protein that was partially fractionated by air classification to protein-enriched fractions containing less chitin. In addition to the significant difference in the coarse mouthfeel between the fine and coarse fractions, the fine fraction of crickets was perceived saltier and more intense in flavour, and the fine fraction of mealworms having more meat-like flavour than the coarse fraction. Thus, it seems that the fractionation process has a clear impact on the texture (coarseness), but the flavour characteristics could be varied according to the insect variety. Overall, the dry fractionation technology holds promising prospects for the production of insect-based food ingredients that are modified in their chitin content and flavour intensity, does not contain identifiable anatomical parts, and thus, could better meet consumer acceptance.