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  • Vainio, Lari; Ellis, Rob (2020)
    This article reviews evidence for the special inhibitory mechanisms required to keep response activation related to affordances of a non-target object from evoking responses. This evidence presents that response activation triggered by affordances of a non-target are automatically inhibited resulting, for example, in decelerated response speed when the response is compatible with the affordance. The article also highlights the neural processes that differentiate these non-target-related affordance effects from other non-target-related effects such as the Eriksen flanker effect that-contrary to these affordance effects-present decelerated response speed when there is incompatibility between the non-target and the response. The article discusses the role of frontal executive mechanisms in controlling action planning processes in these non-target-related affordance effects. It is also proposed that overlapping inhibition mechanisms prevent executing impulsive actions relative to affordances of a target and exaggerate inhibition of response activation triggered by affordances of a non-target.
  • Arte, Elisa; Huang, Xin; Nordlund, Emilia; Katina, Kati (2019)
    The effect of three combinations of bioprocessing methods by lactic acid fermentation, cell wall hydrolyzing enzymes and phytase on the biochemical (protein, fat, carbohydrate composition) and technofunctional properties (protein solubility, emulsifying and foaming properties) of wheat bran protein isolates were evaluated. The bioprocessing increased the protein (up to 80%) and fat content (up to 22.8%) in the isolates due to the degradation of starch and soluble pentosans. Additional proteins, globulin 3A and 3C, chitinase, beta-amylase and LMW glutenins, were identified from the electrophoretic pattern of the protein isolate bioprocessed with added enzymes. Generally, the bioprocessed protein isolate had lower protein solubility and stronger net charge in pH below 7, when compared to the protein isolate made without bioprocessing. The emulsifying properties of the protein isolates were not affected by bioprocessing. However, the foaming stability of the protein isolates was nearly doubled by bioprocessing with cell wall hydrolyzing enzymes and phytase.
  • Calligaris, Sonia; Plazzotta, Stella; Valoppi, Fabio; Anese, Monica (2018)
    Combinations of ultrasound (US) and high-pressure homogenization (HPH) at low-medium energy densities were studied as alternative processes to individual US and HPH to produce Tween 80 and whey protein stabilized nanoemulsions, while reducing the energy input. To this aim, preliminary trials were performed to compare emulsification efficacy of single and combined HPH and US treatments delivering low-medium energy densities. Results highlighted the efficacy of US-HPH combined process in reducing the energy required to produce nanoemulsions stabilized with both Tween 80 and whey protein isolate. Subsequently, the effect of emulsifier content (1-3% w/w), oil amount (10-20% w/w) and energy density (47-175 MJ/m(3)) on emulsion mean particle diameter was evaluated by means of a central composite design. Particles of 140-190 nm were obtained by delivering 175 MJ/m(3) energy density at emulsions containing 3% (w/w) Tween 80 and 10% (w/w) oil. In the case of whey protein isolate stabilized emulsions, a reduced emulsifier amount (1% w/w) and intermediate energy density (120 MJ/m(3)) allowed a minimum droplet size around 220-250 nm to be achieved. Results showed that, in both cases, at least 50% of the energy density should be delivered by HPH to obtain the minimum particle diameter.
  • Wiedenmann, Verena; Oehlke, Kathleen; van der Schaaf, Ulrike; Koivula, Hanna; Mikkonen, Kirsi S.; Karbstein, Heike P. (2019)
    Protein films can be applied to improve food quality and to reduce packaging waste. To overcome their poor water barrier properties, lipids are often incorporated. The function of incorporated lipid depends on the interface between filler and matrix. This study aimed to tailor the properties of a protein–lipid film by designing the oil/water interface to see if the concept of inactive/active filler is valid. Therefore, we varied the emulsifier stabilizing solid lipid nanoparticles (SLN) to promote (viaβ-lactoglobulin) or to minimize (via Tween 20) interactions between particle surface and protein. SLN were incorporated into protein films and film properties were determined. Addition of SLN led to significantly decreased water vapor permeability (WVP) of protein films. However, WVP was mainly affected by the emulsifiers and not by the lipid. Protein-stabilized SLN (BS) replaced a lacking protein in the protein network and therefore did not influence the mechanical properties of the films at ambient temperature. BS-composite films were temperature sensitive, as lipid and sucrose palmitate melted at temperatures above 40°C. Tween 20-stabilized SLN(TS) led to reduced tensile strengths, probably due to perturbative effects of TS and plasticizing effects of Tween 20. Dynamic mechanical analysis showed that TS and Tween 20 increased film mobility. Melting of lipid and emulsifiers, and temperature-dependent behavior of Tween 20 led to a strong temperature dependence of the film stiffness. By designing the interface, particles can be used to tailor mechanical properties of protein films. Tuned edible films could be used to control mass transfers between foods.
  • Korpela, Bei; Pitkänen, Leena; Heinonen, Marina (2022)
    The effect of enzyme treatment on protein-tannin interactions was investigated using up-to-date analytical approaches for improving their physical properties. The formation of ligands between procyanidin B2 and native oat globulin (OG) was observed to be affected by the ratio of procyanidin B2 to OG and the availability of tryptophan. For the transglutaminase-treated OG, the results obtained from circular dichroism (CD) and size exclusion chromatography (SEC) revealed that procyanidin B2 acted as an acyl acceptor in the process of OG deamidation. Procyanidin B2 also inhibited the non-covalent protein-protein interactions occurring between the aromatic side-chains or sedimentation of tryptophan aggregates. For trypsin-treated OG, procyanidin B2 interacted with phenylalanine and the tryptophan side-chain of OG. The inhibition of procyanidin B2 towards protein-protein aggregation was proved by the observation of CD, SEC and asymmetric flow field-flow fractionation.
  • Wang, Yaqin; Tuccillo, Fabio; Lampi, Anna-Maija; Knaapila, Antti; Pulkkinen, Marjo; Kariluoto, Susanna; Coda, Rossana; Edelmann, Minnamari; Jouppila, Kirsi; Sandell, Mari; Piironen, Vieno; Katina, Kati (2022)
    Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.
  • Xu, Yan; Pitkänen, Leena; Maina, Ndegwa Henry; Coda, Rossana; Katina, Kati; Tenkanen, Maija (2018)
    The aim of this study was to study the interactions between dextran and fava bean protein. Two dextrans produced by Leuconostoc pseudomesenteroides DSM 20193 and Weissella cibaria Sj 1b were purified and mixed with fava bean protein isolate (FPI) in water or in different buffers. The two isolated dextrans presented a typical dextran structure, mainly alpha-(1 -> 6) linkages (above 95%) and few alpha-(1 -> 3) branches, but they differed in molar mass and conformation. Dry-heating incubation of FPI and dextran mixture facilitated the conjugation of dextran to FPI through the Maillard reaction. Both mixed and conjugated systems were further heat-treated, and different influences of the formed covalent bonds on rheological properties were observed. The W. cibaria Sj 1b dextran had a much higher gel-strengthening ability than the Ln. pseudomesenteroides DSM 20193 dextran. The intermolecular FPI-dextran interactions played an important role in stabilizing the mixed systems at different pH.