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Dunge, Alice, 2019. Mechanical properties of films made of faba bean protein nanofiber and non-fibrillated protein. Second cycle, A2E. Uppsala: SLU, Department of Molecular Sciences

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Abstract

The production of livestock puts a huge strain on our ecosystem and the planet. It is the largest source of greenhouse gases and it causes loss in biodi-versity and pollution of water. One way to reduce these environmental dam-ages is to decrease the intake of meat and increase the intake of plant-based proteins. However, the sensory feeling of meat is something many people prefer, creating the need to find a plant-based substitute that still fulfills the sensory need the consumers have. The faba bean is a legume that has similar properties to the soybean but is able to grow in colder climate countries. The faba bean is a legume with high levels of proteins that has similar properties to the soybean but is able to grow in colder climates countries. In recent years the creation of amyloid nanofibrils from proteins, for example from faba beans, and their unique mechanical properties has become an area of high interest. Potentially, they can be used to create a meat-like substitute and in that way fulfill that sensory need the consumers have. This study therefore aims to conform nanofibrils from the extracted faba beans proteins that can be used as raw materials to create a texturized vegetal-based food.
Films as systems models were developed from different concentrations of protein nanofibrils and the mechanical properties of each film were evaluated in terms of young modulus (modulus of elasticity), maximum strain and breaking strength. The influence of the concentration of nanofibrils in the modulus of elasticity of the films were assessed to establish a correlation be-tween the film structure and the mechanical properties (i.e., stiffness of the film). To achieve this faba bean proteins were isolated by alkaline precipita-tion and fibrillated by an acid treatment at high temperature.
Films were made with a combination of glycerol plasticizer, faba bean pro-teins, and faba bean protein nanofibrils with an increasing concentration ratio of the nanofibrils. The mechanical properties of films were tested with help of a tensile tested to determine their stress-strain curve and therefore, their stiffness and elasticity. The result showed a successful isolation of protein from the faba bean. The film casting, and tensile test were however inconclu-sive, showing irregular films and variating data with no correlation between concentrations of nanofibrils and the modulus of elasticity. There are multiple theories why this may be, such as bacteria growth, bubbles trapped within the film, lack of nanofibrils or fibril break down during process.

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Produktionen av boskap är en stor påfrestning på vårt ekosystem och därmed vår planet. Den är den största källan till växthusgaser, och orsakar förluster i biodiversiteten och även förorening av vatten. En möjlighet till att lösa dessa miljöproblem är att minska intaget av kött och öka intaget av växtbaserade livsmedel. Det finns dock en del hinder för denna möjlighet, framför allt att många konsumenter föredrar den speciella sensoriska egenskaper som kött har vilket skapar behovet av ett köttliknande vegetabiliskt livsmedel. Faba-bönan är en proteinrik baljväxt med liknande egenskaper som sojabönan, men som kan växa i kallare klimat. Forskare har på senare år fått upp intresset för att använda extraherat protein från bl.a. fababönor för att skapa nanofibriller då dessa har visat sig ha intressanta mekaniska egenskaper. Potentiellt skulle dessa fibriller kunna användas för att skapa köttliknande substitut och därmed fylla det sensoriska behovet hos vissa konsumenter. I den här studien var må-let att skapa fibriller ifrån extraherat protein från fababönor och undersöka deras mekaniska egenskaper i ett filmbaserat modellsystem. Filmer bildades med en kombination fababön-fibriller, protein och glycerol, med en gradvis ökning av fibrillfraktionen. Filmer testade med hjälp av en dragcell och deras mekaniska egenskaper undersökes med Young’s moduls, maximal belastning och styrkan vid brytpunkten. Resultaten visade på en lyckad isolation av pro-teiner från fababönor. Däremot var resultaten från filmformationen och tensil-testerna ofullständiga med ojämna filmer och varierande data utan någon tyd-lig korrelation mellan koncentrationen av fibriller och filmernas mekaniska egenskaper. Det finns flera förklaringar till hur detta kan komma sig, så som bakterietillväxt, luftbubblor som fastnat i filmerna, brist på fibriller eller att fibrillerna bröts ned under processens gång.

Main title:Mechanical properties of films made of faba bean protein nanofiber and non-fibrillated protein
Authors:Dunge, Alice
Supervisor:herneke, Anja
Examiner:Langton, Maud
Series:Molecular Sciences
Volume/Sequential designation:2019:12
Year of Publication:2019
Level and depth descriptor:Second cycle, A2E
Student's programme affiliation:NY002 Agricultural Programme - Food Science 270 HEC
Supervising department:(NL, NJ) > Department of Molecular Sciences
Keywords:Faba bean, amyloid, fibrils, meat substitutes, elasticity, stiffness, proteins
URN:NBN:urn:nbn:se:slu:epsilon-s-10974
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-10974
Subjects:Food science and technology
Language:English
Deposited On:30 Sep 2019 10:46
Metadata Last Modified:04 Jun 2020 11:28

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