Browsing by Subject "emulsion gel"

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  • Suryanarayanan, Tilak (Helsingfors universitet, 2015)
    The objective of the thesis was to investigate the effect of carbohydrates on solubility, emulsifying, gelling and water holding properties of proteins. Faba bean is a readily available pulse crop with high protein content similar to soy bean and there is a lot of potential for a novel, high protein fermented gel product to be made from a pulse crop like faba bean. This is mainly due to its remarkable nutritional properties, functional properties and low cost, the demand for faba bean protein ingredients will grow. The current study was an attempt to develop pulse protein based products – emulsion (milk-like) and emulsion gel (yogurt-like) from faba bean. It seeks to expand the field of application of faba bean protein based products. Faba bean was pretreated, dehulled and milled. The flour was made into suspensions and the starch in faba bean was subjected to amylolytic treatments (addition of alpha amylase and glucoamylase) to breakdown the starch into smaller particles. These treated suspensions were then homogenized to obtain emulsion. A protein based gel network was produced with the gelation of amylolytically treated faba bean proteins. The emulsion properties, specifically droplet size, stability and activity were tested by PAMAS Particle Counter System. Light microscopy was applied to reveal the microstructure of emulsion and emulsion gel. Emulsion gel texture properties were studied by texture analysis. The emulsions were relatively stable over a period of a month and had white ‘milk’ like appearance. The emulsion gels prepared (amylolytic treatment) had slightly higher water holding capacities than the control A (entire starch present) and control B (starch removed by filtration) emulsion gels. Texture analysis of the emulsion gels showed that more force was required by probe to penetrate the yogurt produced from amylolytically treated samples and less force was required to penetrate the yogurt produced from controls A and B. The yield of the emulsion gels were higher for the amylolytically treated samples. It can be concluded that amylolytic treatment has increased the water holding capacity and also resulted in stronger gel systems.
  • Wang, Jing (Helsingin yliopisto, 2015)
    The faba bean (Vicia faba L.) is an economical protein source used in food and feed worldwide. It has high protein content and well-balanced amino acid composition. Since the starch fraction of faba beans causes problems in protein gelation, it hinders the use of whole faba beans for tofu production. Due to economical, ecological and nutritional reasons, it is worthwhile to develop a new way for producing whole faba bean tofu without discarding any part of faba beans. The aim of this thesis work was to produce whole faba bean glucono-𝛿-lactone (GDL) tofu by the starch amylolysis treatment and to study the impact of starch hydrolysate on faba bean tofu properties. This research investigated the changes in faba bean emulsion and emulsion gel properties with or without the starch hydrolysate. The pH and soluble protein content of faba bean suspensions with different GDL concentrations were measured. The microstructure, particle size distribution and viscosity of faba bean emulsions were studied. Moreover, the rheological and textural properties, microstructure, water holding capacity and total solid content of faba bean emulsion gels (GDL tofu) were also investigated. In addition, the contribution of different protein-protein interactive forces to the maintenance of faba bean emulsion gels was evaluated by comparing the protein resolubilization extent of the gels immersed in different reagents. Whole faba bean GDL tofu was prepared by the starch amylolysis treatment, emulsification and gelation processes. The starch hydrolysate containing faba bean emulsion gel was less elastic and more viscous than the starch-free gel. The presence of the starch hydrolysate increased the pH and viscosity of faba bean emulsions, which resulted in weakened protein-protein interactions. The starch hydrolysate significantly reduced the contribution of disulfide bonds to the maintenance of faba bean gel networks, but it increased the contribution of non-covalent interactions. In addition, the microstructure of the starch hydrolysate containing faba bean emulsion gel was not as fine and uniform as that of the starch-free gel. The presence of the starch hydrolysate lowered the water holding capacity and decreased the gel strength of faba bean tofu. All in all, the quality of the whole faba bean GDL tofu containing the starch hydrolysate was not comparable to that of the starch-free faba bean tofu, and further improvements are still required to improve its quality.