How Does Alkali Aid Protein Extraction in Green Tea Leaf Residue: A Basis for Integrated Biorefinery of Leaves
Zhang, C. ; Sanders, J.P.M. ; Xiao, T.T. ; Bruins, M.E. - \ 2015
PLoS ONE 10 (2015)7. - ISSN 1932-6203
functional-properties - antioxidant activity - sugar-beet - cell-walls - cellulose - pectins - biomass - acid - degradation - hydrolysis
Leaf protein can be obtained cost-efficiently by alkaline extraction, but overuse of chemicals and low quality of (denatured) protein limits its application. The research objective was to investigate how alkali aids protein extraction of green tea leaf residue, and use these results for further improvements in alkaline protein biorefinery. Protein extraction yield was studied for correlation to morphology of leaf tissue structure, protein solubility and hydrolysis degree, and yields of non-protein components obtained at various conditions. Alkaline protein extraction was not facilitated by increased solubility or hydrolysis of protein, but positively correlated to leaf tissue disruption. HG pectin, RGII pectin, and organic acids were extracted before protein extraction, which was followed by the extraction of cellulose and hemi-cellulose. RGI pectin and lignin were both linear to protein yield. The yields of these two components were 80% and 25% respectively when 95% protein was extracted, which indicated that RGI pectin is more likely to be the key limitation to leaf protein extraction. An integrated biorefinery was designed based on these results. Introduction
Production of structured soy-based meat analogues using simple shear and heat in a Couette Cell
Krintiras, G.A. ; Gobel, T.W. ; Goot, A.J. van der; Stefanidis, G.D. - \ 2015
Journal of Food Engineering 160 (2015). - ISSN 0260-8774 - p. 34 - 41.
calcium caseinate dispersions - functional-properties - process parameters - extrusion-cooking - fibrous materials - protein isolate - wheat gluten - microstructure - mixtures - system
A Couette Cell device was employed to provide proof of concept for the production of structured meat analogues by application of simple shear flow and heat to a 31 wt% Soy Protein Isolate (SPI)–Wheat Gluten (WG) dispersion. Three relevant process parameters (temperature, time and rotation rate) were varied over a range of realistic values (90–110 °C, 5–25 min and 5–50 RPM, respectively). Layer- or fibre-structured products with high stress and strain anisotropy indices have been demonstrated. Fibrousness is favoured at temperatures over 90 °C and under 100 °C, whereas the role of process time and rotation rate is not critical. Simultaneous application of simple shear and heat is the key to obtaining structured plant protein-based products. The Couette Cell concept is scalable and can enable continuous operation. On this ground, it appears as a realistic option for production of meat analogues at commercial scale.
Method Development to Increase Protein Enrichment During Dry Fractionation of Starch-Rich Legumes
Pelgrom, P.J.M. ; Boom, R.M. ; Schutyser, M.A.I. - \ 2015
Food Bioprocess Technology 8 (2015)7. - ISSN 1935-5130 - p. 1495 - 1502.
air-classified protein - functional-properties - flours - bodies - seeds - pea - efficiency - yield - food
A facile method was developed to establish milling settings that optimally separate starch granules from protein bodies and cell wall fibres for starch-rich legumes. Optimal separation was obtained for pea, bean, lentil and chickpea when the particle size distribution curve of flour and isolated starch granules overlap maximally. This outcome was based on scanning electron microscopy, protein content of the fine fraction and particle size distribution curves. Milling settings differed between legumes due to variances in seed hardness and starch granule size. The protein content of the fine fraction was legume specific as well and could be explained by differences in particle density, seed hardness, starch granule size, fat content and flour dispersibility.
Aqueous fractionation yields chemically stable lupin protein isolates
Berghout, J.A.M. ; Marmolejo-Garcia, C. ; Berton-Carabin, C.C. ; Nikiforidis, C.V. ; Boom, R.M. ; Goot, A.J. van der - \ 2015
Food Research International 72 (2015). - ISSN 0963-9969 - p. 82 - 90.
in-water emulsions - seed oil bodies - oxidative stability - antioxidant properties - lipid oxidation - physicochemical properties - functional-properties - quality - acids - polysaccharides
The chemical stability of lupin protein isolates (LPIs) obtained through aqueous fractionation (AF, i.e. fractionation without the use of an organic solvent) at 4 °C or 20 °C was assessed. AF of lupin seeds results in LPIs containing 2 wt.% oil. This oil is composed of mono- and poly-unsaturated fatty acids and the isolate may thus be prone to lipid and protein oxidation. Lipid and protein oxidation marker values of LPIs obtained at 4 °C and at 20 °C were below the acceptability limit for edible vegetable oils and meat tissue protein; the level of lipid oxidation markers was lower at 20 °C than at 4 °C. The fibre-rich pellet and the protein-rich supernatant obtained after AF also had lower levels of oxidation markers at 20 °C than at 4 °C. This is probably the result of a higher solubility of oxygen in water at lower temperature, which could promote lipid oxidation. The differences between fractions can be explained by the differences in their composition; the fibre-rich pellet contains polysaccharides that potentially have an anti-oxidative effect, while the protein-rich supernatant is rich in sulphur-rich proteins that may scavenge metal ions and free radicals from the aqueous phase. Additionally, the differences in solubility of metal ions and metal-chelating properties of protein at pH 4.5 and pH 7.0 explain the higher level of oxidation in the LPI at pH 4.5 compared with the LPI at pH 7.0. The application of a heat treatment to reduce oxidation decreased the protein and oil recovery values, and increased oxidation values above the acceptability limit. Therefore, AF at 20 °C is the most suitable process to obtain chemically stable LPIs.
Starch facilitates enzymatic wheat gluten hydrolysis
Hardt, N.A. ; Boom, R.M. ; Goot, A.J. van der - \ 2015
Food Science and Technology = Lebensmittel-Wissenschaft und Technologie 61 (2015)2. - ISSN 0023-6438 - p. 557 - 563.
functional-properties - foaming properties - protease - flour - acid
Wheat gluten can be hydrolyzed by either using (vital) wheat gluten or directly from wheat flour. This study investigates the influence of the presence of starch, the main component of wheat, on enzymatic wheat gluten hydrolysis. Wheat gluten present in wheat flour (WFG) and vital wheat gluten (VWG) were hydrolyzed at constant protein concentrations, but subsequently 5.6 times higher amounts of wheat flour. Nevertheless, WFG hydrolysis at 40% total solids resulted in significantly higher degrees of hydrolysis (DH%) than VWG hydrolysis at 7.2% solids. This difference increased to up to 4.5% in 6 h and diminished again for longer reaction times. Possible differences in the gluten composition and the presence of albumins and globulins in wheat flour could not explain the difference in DH% because the addition of starch to VWG increased the rate of hydrolysis similarly. Instead, it was concluded that starch granules impede gluten aggregation, which facilitates the hydrolysis. At higher solid concentrations of up to 70% wheat flour, the positive effect of starch disappeared, because WFG hydrolysis was hindered by mass transfer limitations and lower water activities.
Sustainability assessment of oilseed fractionation processes: A case study on lupin seeds
Berghout, J.A.M. ; Pelgrom, P.J.M. ; Schutyser, M.A.I. ; Boom, R.M. ; Goot, A.J. van der - \ 2015
Journal of Food Engineering 150 (2015). - ISSN 0260-8774 - p. 117 - 124.
functional-properties - exergy analysis - protein - food - feed - fiber - acid
Traditional ingredient production focusses on high purity and yield, resulting in energy- and resource-intensive fractionation processes. We explored alternative fractionation routes for oilseeds by focussing on functionality and optimal resource use. Lupin seeds were taken as model material because they are rich in protein and oil and they can be grown in moderate climate conditions. Dry fractionation yields functional protein-enriched flours without using water, consumes the least energy and exergy losses are low. Purer protein fractions are obtained via conventional wet or aqueous fractionation, but these processes require large amounts of water and an energy-intensive drying step. With the use of exergy analysis, we demonstrate that water and energy consumption can be reduced by replacing drying steps with concentration steps and by combining dry and aqueous fractionation processes. Finally, by valorising side streams, the exergetic efficiency of all fractionation processes increases.
Understanding the differences in gelling properties between lupin protein isolate and soy protein isolate
Berghout, J.A.M. ; Boom, R.M. ; Goot, A.J. van der - \ 2015
Food Hydrocolloids 43 (2015). - ISSN 0268-005X - p. 465 - 472.
heat-induced gelation - functional-properties - globular-proteins - sulfhydryl-groups - thermal gelation - gel strength - rich foods - pea - angustifolius - stability
The gelling properties of lupin protein isolate (LPI) were compared with those of soy protein isolate (SPI). It was found that LPI behaves fundamentally different than SPI, evidenced by the formation of weaker and deformable gels. Further investigation shows that both protein isolates can be considered particle gels and that LPI particles do not swell as much as SPI particles inside the network. Besides, heating hardly affects LPI particles while SPI particles show additional swelling. To explain the differences, the sulfhydryl reactivity of LPI was tested. The amount of free sulfhydryl groups on LPI was higher than the amount of free sulfhydryl groups on SPI. Upon heating the amount of free sulfhydryl groups on LPI increases. We hypothesize that the compact, heat stable structure of the protein particles suppresses the intermolecular bonding through disulphide bridge formation and favours intramolecular crosslinking. The small sulphur-rich proteins that are not incorporated within the particles but are present in the surrounding solution cannot strengthen the particle network, due to their low concentration. LPI did not form gels of similar consistency as SPI and may therefore be less useful for solid food products. The thermal stability of LPI could offer opportunities for high-protein foods that require low viscosity after heating.
Design, properties, and applications of protein micro- and nanoparticles
Saglam, D. ; Venema, P. ; Linden, E. van der; Vries, R.J. de - \ 2014
Current Opinion in Colloid and Interface Science 19 (2014)5. - ISSN 1359-0294 - p. 428 - 437.
microparticulated whey proteins - beta-lactoglobulin - phase-separation - heat-stability - gelatin/maltodextrin mixtures - polysaccharide complexes - rheological properties - functional-properties - biopolymer particles - controlled delivery
The design of protein particles with tailored properties has received an increased attention recently. Several approaches, from simple heat treatment in dilute systems to the combination of heat and mechanical treatments in concentrated protein solutions, have been used to obtain protein particles with varying functional properties. Control of particle size, morphology, surface- and internal properties is crucial for obtaining protein particles with the necessary properties for emerging applications. The latter include not only the use of protein particles in foods, where they can improve the stability of foods at high protein content, but also as food-grade particles for the delivery of bio-actives. By tuning the morphology and size of protein particles, protection or controlled release of various bio-active components may be obtained. We review the various methods that have been used to prepare protein particles and discuss the behavior of the particles in dispersed systems and their possible applications.
Influence of water availability on the enzymatic hydrolysis of proteins
Butré, C.I. ; Wierenga, P.A. ; Gruppen, H. - \ 2014
Process Biochemistry 49 (2014)11. - ISSN 1359-5113 - p. 1903 - 1912.
substrate-inhibition - functional-properties - ionic-strength - amino-acid - hydration - nmr - macromolecules - mechanism - kinetics - protease
The overall rate of enzymatic protein hydrolysis decreases with increasing protein concentration (0.1–30% (w/v)) at constant enzyme/substrate ratio. To understand the role of water, the amount of available water was expressed as the ratio between free and bound water and experimentally determined from water activity and T2 relaxation time (NMR) measurements. At low protein concentrations a large excess of water is present (1.5 × 106 water molecules per protein molecule at 0.1% (w/v) whey protein isolate (WPI), but only 3984 at 30% (w/v) WPI. Assuming that 357 molecules of water are needed for full hydration of the protein, these values correspond to a 4280 and 11 times excess of water, showing that at 30% (w/v) WPI the amount of water becomes limited. At the same time, only a small decrease was observed in water activity (1.00–0.997 for 0.1–30% (w/v) WPI), and an increase of bound water measured by NMR (
Determination of the Influence of Substrate Concentration on Enzyme Selectivity Using Whey Protein Isolate and Bacillus licheniformis Protease
Butré, C.I. ; Sforza, S. ; Gruppen, H. ; Wierenga, P.A. - \ 2014
Journal of Agricultural and Food Chemistry 62 (2014)42. - ISSN 0021-8561 - p. 10230 - 10239.
beta-lactoglobulin - functional-properties - mass-spectrometry - hydrolysis - peptide - endopeptidase - sequence - casein - model
Increasing substrate concentration during enzymatic protein hydrolysis results in a decrease in hydrolysis rate. To test if changes in the mechanism of hydrolysis also occur, the enzyme selectivity was determined. The selectivity is defined quantitatively as the relative rate of hydrolysis of each cleavage site in the protein. It was determined from the identification and quantification of the peptides present in the hydrolysates. Solutions of 0.1–10% (w/v) whey protein isolate (WPI) were hydrolyzed by Bacillus licheniformis protease at constant enzyme-to-substrate ratio. The cleavage sites were divided into five groups, from very high (>10%) to very low selectivity (
Biorefinery methods for separation of protein and oil fractions from rubber seed kernel
Widyarani, R. ; Ratnaningsih, E. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
Industrial Crops and Products 62 (2014). - ISSN 0926-6690 - p. 323 - 332.
aqueous enzymatic extraction - supercritical carbon-dioxide - hevea-brasiliensis seeds - biodiesel production - functional-properties - alpha-lactalbumin - nutritive-value - amino-acids - products - recovery
Biorefinery of rubber seeds can generate additional income for farmers, who already grow rubber trees for latex production. The aim of this study was to find the best method for protein and oil production from rubber seed kernel, with focus on protein recovery. Different pre-treatments and oil separation methods were tested, and alkaline conditions were used to extract protein. Next to processes with subsequent oil and protein recovery, a one-step combined oil and protein extraction was tested. Our study showed that oil separation is not necessary to obtain high protein recovery, however most of the extracted oil is present as an emulsion. The origin of the seeds and their treatment on the plantation before processing were most important for high oil and protein recoveries, and in all cases tested had more influence on recoveries than its subsequent method of processing. Pressing the rubber seed kernel to separate the oil fraction followed by protein extraction from the press cake gives the highest protein recovery with satisfactory recovery for oil.
Factors Impeding Enzymatic Wheat Gluten Hydrolysis at High Solid Concentrations
Hardt, N.A. ; Janssen, A.E.M. ; Boom, R.M. ; Goot, A.J. van der - \ 2014
Biotechnology and Bioengineering 111 (2014)7. - ISSN 0006-3592 - p. 1304 - 1312.
functional-properties - water activity - plastein synthesis - biomass - lignocellulose - inhibition - proteins - softwood
Enzymatic wheat gluten hydrolysis at high solid concentrations is advantageous from an environmental and economic point of view. However, increased wheat gluten concentrations result in a concentration effect with a decreased hydrolysis rate at constant enzyme-to-substrate ratios and a decreased maximum attainable degree of hydrolysis (DH%). We here identified the underlying factors causing the concentration effect. Wheat gluten was hydrolyzed at solid concentrations from 4.4% to 70%. The decreased hydrolysis rate was present at all solid concentrations and at any time of the reaction. Mass transfer limitations, enzyme inhibition and water activity were shown to not cause this hydrolysis rate limitation up to 50% solids. However, the hydrolysis rate limitation can be, at least partly, explained by a second-order enzyme inactivation process. Furthermore, mass transfer impeded the hydrolysis above 60% solids. Addition of enzyme after 24 h at high solid concentrations scarcely increased the DH%, suggesting that the maximum attainable DH% decreases at high solid concentrations. Reduced enzyme activities caused by low water activities can explain this DH% limitation. Finally, a possible influence of the plastein reaction on the DH% limitation is discussed.
Critical parameters in cost-effective alkaline extraction for high protein yield from leaves
Zhang, C. ; Sanders, J.P.M. ; Bruins, M.E. - \ 2014
Biomass and Bioenergy 67 (2014). - ISSN 0961-9534 - p. 466 - 472.
leaf protein - functional-properties - chemical-composition - amino-acids - tea-leaves - biomass - concentrate - refinery - feed
Leaves are potential resources for feed or food, but their applications are limited due to a high proportion of insoluble protein and inefficient processing. To overcome these problems, parameters of alkaline extraction were evaluated using green tea residue (GTR). Protein extraction could be maximized to 95% of total protein, and, after precipitation by pH adjustment to 3.5, 85% of extracted protein was recovered with a purity of 52%. Temperature, NaOH amount, and extraction time are the protein yield determining parameters, while pH and volume of extraction liquid are critical parameters for production cost. The cost of energy and chemicals for producing 1 t GTR proteins is minimized to 102€, and its nutritional value is comparable to soybean protein. Furthermore, this technology was successfully applied to other sources of biomass and has potential to be used as a part of an integrated bio-refinery process.
The potential of aqueous fractionation of lupin seeds for high-protein foods
Berghout, J.A.M. ; Boom, R.M. ; Goot, A.J. van der - \ 2014
Food Chemistry 159 (2014). - ISSN 0308-8146 - p. 64 - 70.
functional-properties - isoelectric precipitation - rheological properties - thermal-damage - albus - angustifolius - ultrafiltration - sustainability - isolate - sweet
Aqueous fractionation of protein from lupin seeds was investigated as an alternative to the conventional wet fractionation processes, which make use of organic solvents. The effect of extraction temperature was studied and the consequences for downstream processing were analysed. Omitting the extraction of oil with organic solvents resulted in a protein isolate that contained 0.02–0.07 g oil g-1 protein isolate, depending on the exact extraction conditions. Nevertheless, the protein functionality of the aqueous fractionated lupin protein isolate was similar to the conventional lupin protein isolate. The protein isolate suspension could be concentrated to 0.25 g mL-1 using ultrafiltration, which provides a relevant concentration for a range of high-protein products. Based on the results, we conclude that aqueous fractionation can be a method to lower the environmental impact of the extraction of proteins from legumes that contain water- and dilute salt-soluble proteins.
Fibril Formation from Pea Protein and Sesequent Gel Formation
Munialo, C.D. ; Martin, A.H. ; Linden, E. van der; Jongh, H.H.J. de - \ 2014
Journal of Agricultural and Food Chemistry 62 (2014)11. - ISSN 0021-8561 - p. 2418 - 2427.
beta-lactoglobulin gels - amyloid fibrils - ph 2.0 - electrostatic interactions - functional-properties - circular-dichroism - globular-proteins - heat - gelation - behavior
The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of ß-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels.
Concentrated whey protein particle dispersions: Heat stability and rheological properties
Saglam, D. ; Venema, P. ; Vries, R.J. de; Shi, J. ; Linden, E. van der - \ 2013
Food Hydrocolloids 30 (2013)1. - ISSN 0268-005X - p. 100 - 109.
colloidal dispersions - functional-properties - thermal-stability - microparticles - beverage - delivery - powders - size
In this work heat stability and rheological properties of concentrated whey protein particle dispersions in different dispersing media are studied. Whey protein particles (protein content ~20% w/v) having an average size of a few microns were formed using a combination of two-step emulsification and heat-induced gelation. Particles were dispersed (volume fraction of particles ~ 0.35) in solutions of Na-caseinate, whey protein isolate or gum arabic at different concentrations. The microstructure, particle size distribution and flow behaviour of the dispersions were analyzed before and after heating at 90oC for 30 min. All dispersions were liquid-like and no significant change in the microstructure was observed after heat treatment. Viscosity measurements showed that both the type and the concentration of the stabilizer influenced the viscosity changes after heat treatment. When 1% (w/w) gum arabic was used as stabilizer no change in the viscosity was observed after heat treatment. However, when Na-caseinate or whey protein isolate was used, viscosity increased in low-shear regime and shear-thickening was observed in high shear regime. Heat treatment did not significantly alter the zeta potential of the particles, whereas the size of the particles increased after heating due to swelling. The results show that swelling of the particles plays a significant role in the heat stability and rheological properties of these dispersions.
Enzyme assisted protein extraction from rapeseed, soybean, and microalgae meals
Sari, Y.W. ; Bruins, M.E. ; Sanders, J.P.M. - \ 2013
Industrial Crops and Products 43 (2013). - ISSN 0926-6690 - p. 78 - 83.
functional-properties - soy protein - antioxidant capacity - conversion factors - phenolic-acids - products - chemicals - biomass - alkaline - heat
Oilseed meals that are by-products from oil production are potential resources for protein. The aim of this work is to investigate the use of enzymes in assisting in the extraction of protein from different oilseed meals, namely rapeseed, soybean, and microalgae meals. In addition, microalgae without prior oil removal was also tested. The extraction was performed varying temperature, pH, and type of enzyme. More protein was extracted at alkaline conditions, compared to acidic conditions. At alkaline pH, 80% protein of soybean meal and 15–30% protein of rapeseed and microalgae meals was extracted without enzyme addition. The addition of enzyme under this condition increased protein extraction yield to 90% for soybean meal and 50–80% for rapeseed and microalgae meals. Here, Protex 40XL, Protex P, and Protex 5L that work at alkaline pH assisted protein extraction particularly for rapeseed and microalgae meals. Microalgae without prior oil removal had the lowest protein extraction yield, illustrating that oil removal prior to protein extraction is beneficial for protein recovery. In general, protein extraction was influenced by pH, the type of biomass, and the addition of enzyme, but not by the type of enzyme that was used.
Production of oligosaccharides from extruded wheat and rye biomass using enzymatic treatment
Makaravicius, T. ; Basinskiene, L. ; Juodeikiene, G. ; Gool, M.P. van; Schols, H.A. - \ 2012
Catalysis today 196 (2012)1. - ISSN 0920-5861 - p. 16 - 25.
secale-cereale l. - dietary fiber - nonstarch polysaccharides - extrusion-cooking - physicochemical properties - extractable arabinoxylans - xylo-oligosaccharides - functional-properties - eucalyptus wood - harvest year
Research on prebiotics and other novel healthpromoting food components has been active for over a decade. Arabinoxylan (AX) derived arabinoxylooligosaccharides (AXOS), which may have various chemical structures, depending on the xylan source and the degradation method used, stand increasingly in the spotlight as potential prebiotics. During the past decade, the studies of the possibilities to produce the AXOS by using biocatalytic conversion have received more attention. In addition, there is an interest in the use of novel cereal biomass for the production of AXOS. The aim of this study was to investigate the influence of various commercial enzyme preparations on the degradability of insoluble arabinoxylans in wheat and rye wholemeal treated by extrusion, identify and quantify xylooligosaccharides (XOS) and arabinoxylooligosaccharides (AXOS) in treated media. The enzymatic degradation of rye and wheat cell wall materials was monitored by HPSEC, HPAEC and MALDITOFMS techniques. It was noticed that there is no significant difference between extruded and natural cereals, and type of cereals had not significant influence on XOS and AXOS production. The most effective biocatalysts were hemicellulases expressed in the enzyme preparations from Trichoderma and Aspergillus spp. (Depol 692), Humicola and Bacillus spp. (Ceremix Plus). Degradability of rye and wheat cell wall materials by these enzyme preparations obtained break down percentages of 70–87% and 67–77%, respectively. After enzymatic treatment, only small amounts of xylose, xylobiose, and xylotriose was eluted compare to the amount of more complex oligosaccharides with higher degree of polymerization (DP). The mass spectra of oligosaccharides indicated the presence of a homologous series of pentoses ranging from DP 4 to 15. This indicates that chosen enzyme preparations acted well on wheat and rye biomass, and released quite high amounts of XOS and AXOS.
Perspectives to breed for improved baking quality wheat varieties adapted to organic growing conditions
Osman, A.M. ; Struik, P.C. ; Lammerts Van Bueren, E. - \ 2012
Journal of the Science of Food and Agriculture 92 (2012)2. - ISSN 0022-5142 - p. 207 - 215.
triticum-aestivum l. - bread-making quality - weight glutenin subunits - nitrogen use efficiency - winter-wheat - protein-composition - spring wheat - breadmaking quality - functional-properties - genetic-improvement
Northwestern European consumers like their bread to be voluminous and easy to chew. These attributes require a raw material that is rich in protein with, among other characteristics, a suitable ratio between gliadins and glutenins. Achieving this is a challenge for organic growers, because they lack cultivars that can realise high protein concentrations under the relatively low and variable availability of nitrogen during the grain-filling phase common in organic farming. Relatively low protein content in wheat grains thus needs to be compensated by a high proportion of high-quality protein. Organic farming therefore needs cultivars with genes encoding for optimal levels of glutenins and gliadins, a maximum ability for nitrogen uptake, a large storage capacity of nitrogen in the biomass, an adequate balance between vegetative and reproductive growth, a high nitrogen translocation efficiency for the vegetative parts into the grains during grain filling and an efficient conversion of nitrogen into high-quality proteins. In this perspective paper the options to breed and grow such varieties are discussed.
Surface activity and molecular characteristics of cuttlefish skin gelatin modified by oxidized linoleic acid
Aewsiri, T. ; Benjakul, S. ; Visessanguan, W. ; Wierenga, P.A. ; Gruppen, H. - \ 2011
International Journal of Biological Macromolecules 48 (2011)4. - ISSN 0141-8130 - p. 650 - 660.
emulsifying properties - peroxidation products - functional-properties - fish gelatin - proteins - emulsions - oil - fluorescence - stability - oxidation
Surface activity and molecular changes of cuttlefish skin gelatin modified with oxidized linoleic acid (OLA) prepared at 60, 70 and 80 °C at different times were investigated. Modification of gelatin with OLA could improve surface activity of resulting gelatin as evidenced by the decreased surface tension and the increased foaming and emulsifying properties. Interaction between OLA and gelatin led to the generation of carbonyl groups, loss of free amino content and the increase in particle size of resulting gelatin. Emulsion stabilized by modified gelatin had the smaller mean particle diameter with higher stability, compared with that stabilized by gelatin without modification.