Studies on quinoa (Chenopodium quinoa) for novel food and beverage applications

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dc.contributor.advisor Arendt, Elke K. en Mäkinen, Outi 2015-11-03T10:18:29Z 2014 2014
dc.identifier.citation Mäkinen, O. 2014. Studies on quinoa (Chenopodium quinoa) for novel food and beverage applications. PhD Thesis, University College Cork. en
dc.identifier.endpage 245
dc.description.abstract Quinoa (Chenopodium quinoa) is a seed crop native to the Andes, that can be used in a variety of food product in a similar manner to cereals. Unlike most plants, quinoa contains protein with a balanced amino acid profile. This makes it an interesting raw material for e.g. dairy product substitutes, a growing market in Europe and U.S. Quinoa can however have unpleasant off-flavours when processed into formulated products. One means of improving the palatability is seed germination. Also, the increased activities of hydrolytic enzymes can have a beneficial influence in food processing. In this thesis, the germination pattern of quinoa was studied, and the influence of quinoa malt was evaluated in a model product. Additionally, to explore its potential for dairy-type products, quinoa protein was isolated from an embryo-enriched milling fraction of non-germinated quinoa and tested for functional and gelation properties. Quinoa seeds imbibed water very rapidly, and most seeds showed radicle protrusion after 8-9 h. The α-amylase activity was very low, and started to increase only after 24 hours of germination in the starchy perisperm. Proteolytic activity was very high in dry ungerminated seeds, and increased slightly over 24 h. A significant fraction of this activity was located in the micropylar endosperm. The incorporation of germinated quinoa in gluten-free bread had no significant effect on the baking properties due to low α-amylase activity. Upon acidification with glucono-δ-lactone, quinoa milk formed a structured gel. The gelation behaviour was further studied using a quinoa protein isolate (QPI) extracted from an embryoenriched milling fraction. QPI required a heat-denaturation step to form gel structures. The heating pH influenced the properties drastically: heating at pH 10.5 led to a dramatic increase in solubility, emulsifying properties, and a formation of a fine-structured gel with a high storage modulus (G') when acidified. Heating at pH 8.5 varied very little from the unheated protein in terms of functional properties, and only formed a randomly aggregated coagulum with a low G'. Further study of changes over the course of heating showed that the mechanism of heat-denaturation and aggregation indeed varied largely depending on pH. The large difference in gelation behaviour may be related to the nature of aggregates formed during heating. To conclude, germination for increased enzyme activities may not be feasible, but the structure-forming properties of quinoa protein could possibly be exploited in dairy-type products. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Outi Mӓkinen. en
dc.rights.uri en
dc.subject Quinoa en
dc.subject Plant protein en
dc.subject Gluten free en
dc.title Studies on quinoa (Chenopodium quinoa) for novel food and beverage applications en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Food Science and Technology) en
dc.internal.availability Full text available en
dc.description.version Accepted Version
dc.description.status Not peer reviewed en Food and Nutritional Sciences en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.chapterOfThesis 8-9
dc.check.embargoformat E-thesis on CORA only en
dc.internal.conferring Spring Conferring 2015

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