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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

IMPACT OF HOMOGENIZATION AND UHT PROCESSING ON THE EMULSIFICATION AND PHYSICAL PROPERTIES OF PEA PROTEIN BEVERAGES

Xiang Cheng (17583861) 10 December 2023 (has links)
<p dir="ltr">Pea protein is one of the most used plant proteins in food products, acting as an alternative to conventional animal protein sources due to its abundant, nutritious, and ease in supply chain characteristics. The objective of this study was to investigate the impact of homogenization and UHT processing parameters on the properties of protein emulsion. Protein emulsions (8% w/w pea protein isolate and 1% w/w sunflower oil) were freshly prepared prior to processing, and the untreated sample was considered as the control (NT). The pilot-scale aseptic processing system (APS) used in this study consisted of two coil-in-shell heaters and two coolers. Samples flowed through each section of the APS system following this order: balance tank, pre-heater, final heater, hold tube, pre-cooler, and final cooler. The homogenizer was located either after the pre-cooler (AC) or the pre-heater (AH) with a controlled temperature of 165F. A third setup was utilized by bypassing the homogenizer in the UHT system. An additional 8-hour continuous run was conducted to mimic a commercial manufacturing operation by recirculating the protein emulsion in the UHT system, and fouling detections were made using a non-intrusive sensor (NICS). 5% w/w soy protein, 1% w/w sunflower oil oil-in-water emulsion was also used for fouling tests. Protein concentration, pH and zeta potential, Cryo-SEM microscopic image, particle size distribution, flocculation index (FI), coalescence index (CI), viscosity and color data were collected and analyzed. The protein concentration had a 23.20 ± 4.00 %, 28.35 ± 5.02 %, 27.98 ± 5.05% and 21.38 ± 5.75% reduction for AC, AH, UHT and NT samples, respectively, when compared with the initial concentration in the formula. AC, AH, UHT and NT samples had pH values of 7.24 ± 0.01, 7.27 ± 0.01, 7.28 ± 0.02, 7.41 ± 0.01, and zeta potential values of -42.91 ± 0.89, -47.30 ± 0.91, -46.91 ± 1.40 and -50.11 ± 1.47 mV. AC sample had a smaller and NT sample had a bigger, respectively, mean weighted size D 4,3 value than AH and UHT samples, which could also be seen in Cryo-SEM images where only AC images contained more visually observable smaller particles. FI and CI for AC, AH and UHT indicated the formation of flocs but no irreversible aggregations were found. Shear-thinning AC, AH, UHT and NT samples had viscosity decreases from 4.00 to 3.56, 3.88 to 3.75, 4.02 to 3.79 and 10.42 to 9.56 mPa*s in 1 1/s to 100 1/s shear rate range. NT sample had a very noticeable color difference from the other three treated samples. Overall, AC samples had similar or better emulsion stability in all aspects than AH and UHT samples, suggesting that AC processing could potentially be used in the protein beverage industry for manufacturing products with improved shelf stability. Severe foulants buildups were neither observed nor detected by a non-intrusive continuous sensor (NICS) in the UHT system within 8 hours of process for both pea protein and soy protein emulsion, indicating that this UHT-homogenization processing can potentially be adapted to current industrial practices for higher-quality protein beverages.</p>
22

Ett doft- och smakbibliotek avseende hampfrö-presskaka, gula mjölmasklarver, texturerad veteprotein, ärtproteinisolat och ärtprotein koncentrat : En sensorisk undersökning av alternativa proteinkällor / A fragrance- and flavour library for hempseed press cake, yellow mealworm, textured wheat protein, pea protein isolate and pea protein concentrate : A sensory study of alternative protein sources

Vu, Michael, Holmberg, Sofie January 2021 (has links)
Syftet med studien är att genom sensoriska analyser sammanställa ett doft- och smakbibliotek för hampfrö-presskaka, gula mjölmasklarver, texturerad veteprotein, ärtproteinisolat och ärtprotein koncentrat. Metoderna pilotstudie, konsensustest och in-house intensitetstest används i studieprocessen. Pilotstudiens syfte är att få en ökad förståelse för produkternas doft och smak. Konsensustestet är en central punkt för uppbyggnaden av doft- och smakbiblioteket, eftersom övervägande attribut som genererats under testet används till produktbeskrivningen i doft- och smakbiblioteket. Inhouse intensitetstestet avsikt är verifiera attributgenereringens validitet från konsensustestet. Resultatet från pilotstudien bidrar med referenser till konsensustestet. Det finns även gemensamma egenskapsord för produkternas doft- och smak i pilotstudien och i konsensustestet. Resultatet från konsensustestet visar att det är svårt att särskilja smak från munkänsla, där till exempel olja kan fastställas som en smak från hampfrö-presskaka. Resultatet från inhouse intensitetstestet har ett större bortfall, vilket gör det svårt att fastställa attributen på grund av differentialen i minimum- och maximum värdet. Attribut som gav en beskrivande text till biblioteket visar att hampfrö-presskaka har en doft av gräs och tång där smak påminner om doft. Ärtproteinisolat doftar framför allt spannmål och smaken påminner om frön och majs. Gula mjölmasklarver doftar cerealier och valnötter, där smaken utgår från grundsmaken umami. Texturerad veteprotein har en doft som kan härledas till rostade vetepuffar och havregryn, där smak påminner om doft. Sista produkten ärtprotein koncentrat, har en doft av ärtskott och en besk smak. / The purpose of the study is to construct a fragrance- and flavour library for sensory analyses for hemp seed press cake, yellow mealworms, textured wheat protein, pea protein isolate and pea protein concentrate. The methods pilot study, consensus test and inhouse intensity test are used to be able to execute the study. The purpose of the pilot study is to gain an increased understanding of the fragrance- and flavour of the pre-products. The consensus test is a central point for the structure of the fragrance- and flavour library, since predominant attributes generated during the test are used for the product description in the fragrance- and flavour library. The purpose of the inhouse intensity test is to verify the validity of the attribute generation from the consensus test. The results from the pilot study contribute with references to the consensus test. There are also common attributes for the products' fragrance- and flavour in the pilot study and in the consensus test. The results from the consensus test show that it is difficult to distinguish between taste and mouthfeel. For example, can oil from hemp seed press cake be determined as a flavour. The result from the inhouse intensity test has a large statistical error, which makes it difficult to determine the attributes due to the differential in the minimum- and maximum value. Attributes that gave a descriptive text to the library show that hemp seed press cake has a scent of grass and seaweed where the taste is reminiscent of the scent. Pea protein isolate mainly smells of grain, the taste is reminiscent of seeds and corn. Yellow mealworms smell like cereals and walnuts where the taste is based on the basic taste umami. Textured wheat protein has a scent that can remind of roasted wheat puffs and oatmeal, where the taste is reminiscent of the scent. The last product is pea protein concentrate, which has a scent of pea shoots, and the taste is bitter.
23

Incorporation and release of organic volatile compounds in a bio-based matrix by twin-screw extrusion / Incorporation et libération de composés organiques volatils dans une matrice d'agromatériaux par extrusion bi-vis

Castro Gutierrez, Natalia 18 February 2016 (has links)
Dans le contexte actuel, les communautés scientifiques et politiques sont centrées sur les différentes manières de mieux préserver et utiliser les ressources naturelles de notre planète. Dans le but de réduire la consommation des matières issues du pétrole, et de développer de nouveaux produits et procédés industriels plus propres, l’industrie des fragrances et des arômes cherche aujourd’hui à développer de nouveaux matériaux bio-sourcés pour protéger leurs molécules volatiles odorantes. Dans ce travail de thèse, les maltodextrines ont été choisies comme composé majoritaire, les protéines de pois et un amidon modifié ont été sélectionnés comme additifs compatibilisants pour la composition des matrices d’agromatériaux. L’incorporation des molécules volatiles odorantes, ainsi que l’élaboration des matrices encapsulantes ont été réalisées en une seule étape, grâce à la technologie d’extrusion bi-vis à basse température. Les caractéristiques physicochimiques, thermiques et morphologiques de ces nouvelles matrices enrobantes ont été analysées, de même que la détermination de leur efficacité d’encapsulation et du profil de libération du principe actif. Les différentes investigations menées ont permis de mieux comprendre l’impact des formulations et de l’incorporation des molécules volatiles odorantes sur les paramètres opératoires. Les interactions entre la matrice enrobante et le principe actif ont également été étudiées. Les conditions d’extrusion établies, ainsi que les caractéristiques de ces nouvelles matrices encapsulantes, s’avèrent être pertinentes pour le domaine de la parfumerie. / Nowadays, scientific and political communities are focused on ways to better preserve and manage the natural resources of our planet. In order to reduce consumption of fossil resources, and to develop more environmentally friendly industrial processes, the industry of flavors and fragrances became interested in developing new bio-based encapsulating materials. In the present work, maltodextrins have been chosen as main component of the matrix, and pea protein isolate and a modified starch were selected as compatibilizing additives. The incorporation of volatile odorant compounds and the elaboration of the new bio-based delivery systems were performed, all in one single step, by low temperature twin-screw extrusion. The physicochemical, thermal and morphological properties of these matrices were studied, as well as the encapsulation efficiency and the release profile of the active compounds. These investigations have led to a better understanding of the impact of the formulations and of the incorporation of the active compound on the process parameters. The interactions between the wall and the encapsulated materials were also analyzed. The characteristics of the new bio-based delivery systems and the established extrusion process conditions were found to be very promising to be employed in the field of perfumery.

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