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Browsing by Subject "oat protein concentrate"

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  • Chandrakusuma, Angga (2016)
    There is a need to find more sustainable sources of protein due to increasing demand and population growth. Dry milling and air classification yields oat protein concentrate (OPC, 45.5% protein) from defatted oat kernels. However, applications of oat protein in foods require improved technological functionalities. The literature review of this study discusses the chemical composition of oats, and modifications of plant protein through thermal treatment, microfluidizer, and high hydrostatic pressure (HHP). The experimental work aimed to understand the effect of heat treatment (40, 60, 80 °C), microfluidization (50 MPa), and high hydrostatic pressure (HPP, 300 and 600 MPa) on the applicability of OPC in semi-solid food matrices. The treatments were performed on OPC suspensions with 2.4, 4.6, 8.5, 12, or 20 % protein. Changes in particle size, protein solubility, surface hydrophobicity, and rheological properties were measured. Stability of OPC dispersion was improved by microfluidizer treatment while HHP at 600 MPa accelerated sedimentation. Viscosity increased significantly by thermal treatment at 80 °C and HHP at 600 MPa. Gel formation occurred at 12 and 20% protein concentration with 80 °C heat treatment. Highest increase in particle size was shown by HHP at 600 MPa resulting in volume mean diameter, d4,3 of 32-38 µm. On the other hand, microfluidizer reduced d4,3 to 3.3-3.4 µm. Protein solubility increased from 13 to 23% by increasing protein concentration from 2.4% to 20%. Protein solubility was improved by 1-1.7% at 2.4-8.5% protein concentration by thermal treatment at 60 °C, homogenization, and HHP at 300 MPa. Protein solubility was reduced by HHP at 600 MPa by 1.4-1.5 %. Protein surface hydrophobicity was increased by thermal treatment at 60 and 80 °C and HHP. Microfluidizer showed slight increase in solubility at 4.6% protein concentration (1.1-1.6 %) and lowered surface hydrophobicity at 8.5% protein concentration. Thermal treatment showed best result in achieving gel-like structure, whereas microfluidization showed potential for stabilising dispersion.
  • Immonen, Mika (2018)
    The literature review of this thesis focused on the composition of grain proteins, extraction methods, rheology, single-unit processes such as temperature, pH or high-pressure for the modification of physicochemical properties of grain proteins. In addition, combined processing methods for texturisation of plant proteins were described. The aim of the experimental study was to study the melting properties of grain proteins. Another aim was to produce protein concentrate from oats to be used in the protein melt studies. In addition, the melting properties of pea protein isolate and blend of pea protein isolate and oat protein concentrate were investigated. The melting properties of grain proteins were analysed with a closed cavity rheometer, which can be used to study the rheological properties of highly concentrated protein matrices in real-time. In the temperature sweep measurement of oat protein concentrate and pea protein isolate blend, three denaturation and polymerisation sections were observed (80, 110 and 140°C). In addition, polymerisation as a function of time was recorded in the time sweep measurements. The melting temperature of grain proteins was an important factor when producing texturised structures from grain proteins.