• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 72
  • 7
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 96
  • 96
  • 67
  • 67
  • 30
  • 30
  • 29
  • 24
  • 21
  • 21
  • 20
  • 19
  • 18
  • 17
  • 14
  • 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.
1

IMPACT OF ALGAE SUPPLEMENTED DIETS COMBINED WITH ANTIOXIDANTS ON THE NUTRITIONAL PROFILE, QUALITY ATTRIBUTES, AND STORAGE STABILITY OF CHICKEN BREAST MEAT

Norcross, Rebecca G. 01 January 2015 (has links)
Consumers’ demands for ω-3 polyunsaturated fatty acids (PUFAs) are at all-time high. Algae, a common source of PUFAs, and antioxidants are both used as supplements in livestock feeds, are known to affect the overall quality of meat. To implement PUFA deposits into broiler meat, this study evaluated combining antioxidants and algae in broiler feed to enhance the breast meat quality. Broilers were fed diets supplemented with 50 IU Vitamin E or 200 g/ton EconomasE (EcoE, an antioxidant pack) plus 10 IU Vitamin E, with or without 0.5% algae extract (SP-1). The feed oil was partially oxidized soybean oil (POV: 86 mEq of O2/kg). The feed supplementation with combined SP-1 and EcoE increased meat lipid oxidation but had no effect on protein. This combination supplement substantially reduced (P < 0.05) meat exudation during refrigerated storage while no evident differences were seen on cooking loss or tenderness between diets. Meat from SP-1 supplemented diets was found less acceptable than meat from other diets due to detected off-flavors. The results indicate that EcoE at a supplementation level other than 200 g/ton may be required to overcome off-flavors of broiler meat due to feed incorporation of 0.5% SP-1 with oxidized oil.
2

Improving oxidative stability of omega-3 enriched pork meat by addition of food grade sugars and sensory characterization of cooked and re-warmed pork meat patties by free choice profiling

PEETHAMBARAN, KRISHNADAS Unknown Date
No description available.
3

Value-addition of cold pressed hemp seed oil and oil by-products through ultrasonic bleaching and heat treatment: evaluation of chlorophyll, oxidative stability and antioxidant activity

Jingbang, Liang 04 May 2016 (has links)
Cold pressed Hemp (Cannabis sativa L) seed oil, which contains a favorable ratio of omega-6/omega-3 and a considerable amount of vitamin E, is a high nutrition value product with various health benefits. However, the presence of a large amount of chlorophyll makes the oil highly susceptible to photo-oxidation and limits its applications. Chlorophyll and other pigments in edible oils are commonly reduced through oil bleaching process. The objective of this study was to reduce the chlorophyll content in cold pressed hemp seed oil using ultrasonic bleaching and evaluate the impacts on carotene content, peroxide value, conjugated diene, total phenolic content and oxidative stability. The bleaching efficiency increased significantly as the ultrasound power (0 to 60% pressure amplitude) and concentration of bleaching clay (20 to 40 g/kg) increased. At 20% ultrasound power, the chlorophyll reduction (%) of different clays was found to be 99.4% (industrial clay) > 97.8% (activated bentonite) > 82.7% (sepiolite) > 47.1% (non-activated bentonite). Ultrasonic bleaching significantly reduced (p<0.05) the total chlorophyll content, total carotene content and primary oxidation products of hemp seed oil. During accelerated oxidation tests (40 and 60 ℃), the developments of peroxide value and conjugated diene were significantly (p<0.05) slower for hemp seed oil treated with ultrasonic bleaching compared to the control oil. Enhanced oxidative stability was observed in hemp seed oil after ultrasonic bleaching. In addition, another objective of this study was to evaluate the impacts of solvent and heat treatment on phenolic profile and antioxidant activity of cold pressed canola and hemp meals. For canola meal, a solvent-mixture of aqueous methanol (70%) and aqueous acetone (70%) in a ratio of 1:1 (v/v) extracted (p<0.05) slightly higher total phenolic content (11.3 mg SAE/g), while aqueous methanol (70%) extracts exhibited higher DPPH scavenging effect (40.4%). For hemp meal, aqueous acetone (80%) extracts exhibited higher total phenolic content (6.0 mg GAE/g) and DPPH scavenging effect (12.5%). Total phenolic content and antioxidant activity in canola meal extracts were significantly higher (p<0.05) than those in hemp meal extracts. After heat treatments at temperature from 140 to 180 ℃, canola and hemp meal extracts showed equal or lower total phenolic content and DPPH scavenging effect. / May 2017
4

Avaliação do potencial do ácido tânico e do líquido extraído da castanha do caju (Anacardium occidentale L) como antioxidante para biodiesel

Mendes, Danylo Bezerra 04 April 2013 (has links)
A estabilidade oxidativa é uma das mais relevantes propriedades que atestam a qualidade de um biodiesel. Esse fato pode comprometer a armazenagem e a sua utilização como combustível e para prevenir esta oxidação, faz-se necessário o uso de compostos que demonstrem eficiência frente ao processo oxidativo em biodiesel. Assim sendo, o presente trabalho teve como objetivo geral avaliar o efeito do Ácido Tânico (AT) e do Líquido extraído da Castanha do Caju (Anacardium occidentale L.) (LCC) como antioxidante para biodiesel, analisando as características gerais da oxidação. Para tanto, foi utilizada uma metodologia onde o estudo da estabilidade do biodiesel foi realizado por meio do Rancimat, termogravimetria, espectrofotometria e análises de acidez. Por meio da análise no Rancimat, constatou-se que todos os biodieseis aditivados apresentaram um aumento do PI (período de indução), ou seja, um aumento da estabilidade oxidativa, de forma progressiva com o aumento da adição do antioxidante. A avaliação termogravimétrica (TGA) empregada demonstrou que o LCC técnico apresentou uma maior temperatura inicial e menor temperatura final de decomposição quando comparado com os demais antioxidantes testados. Os resultados dos testes de acidez e espectrofotometria na armazenagem em estufa e prolongado, com todos os antioxidantes testados, não mostraram aumento significativo da oxidação devido ao tipo de teste empregado, que buscou reproduzir as condições reais de armazenagem. Vale ressaltar que os resultados encontrados nesta pesquisa atendem aos parâmetros de qualidade exigidos pelo órgão regulador dos biocombustíveis, a ANP. / Oxidative stability is one of the most important properties that attest to the quality of a biodiesel. This fact can affect the storage and their use as fuel and to prevent this oxidation, it is necessary the use of compounds that show efficacy against oxidative process into biodiesel. Thus, the present work had as general objective to evaluate the effect of Tannic Acid (TA) and the liquid extracted from the Cashew Nut (Anacardium occidentale L.) (LCC) as antioxidant for biodiesel, analyzing the General characteristics of oxidation. To this end, we used a methodology where the study of the stability of biodiesel was performed by means of Rancimat, Thermogravimetry, spectrophotometry and the analysis of acidity. By means of Rancimat analysis, it was found that all additives biodieseis showed an increase of PI (induction period), an increase of oxidative stability, progressively increasing the addition of antioxidant. The thermogravimetric maid evaluation showed that the LCC a higher initial temperature presented technical and minor final temperature of decomposition when compared with other antioxidants tested. The results of the tests of acidity and spectrophotometry in the kiln and prolonged storage, with all the antioxidants tested, showed no significant increase in oxidation due to the type of test used, which sought to reproduce the actual conditions of storage. It is worth noting that the results found in this research meet the quality parameters required by the regulator of biofuels, the ANP.
5

Tabernaemontana catharinensis como aditivo antioxidante em biodiesel de soja

Ramos, Anelize Felicio 22 February 2018 (has links)
Submitted by Eunice Novais (enovais@uepg.br) on 2018-05-18T18:49:13Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Anelize Ramos.pdf: 1261676 bytes, checksum: cc63fbd3d08ae55a8e35c7d4d7bf932e (MD5) / Made available in DSpace on 2018-05-18T18:49:13Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Anelize Ramos.pdf: 1261676 bytes, checksum: cc63fbd3d08ae55a8e35c7d4d7bf932e (MD5) Previous issue date: 2018-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O biodiesel além de um caráter mercadológico possui base social e ambiental, podendo ser considerado uma fonte energética renovável com diversificação de matérias primas e de meios de produção. Para ser comercializado, o biodiesel, deve atender às especificações de qualidade estabelecidas pela ANP como a estabilidade oxidativa que se relaciona diretamente com a composição, em ácidos graxos, da matéria prima utilizada. Em especial, a presença de ácidos graxos insaturados interfere diretamente sobre a estabilidade oxidativa do biodiesel pois através das ligações múltiplas acontecem as reações de oxidação do mesmo. O uso de aditivos antioxidantes é uma alternativa para aumentar a estabilidade do biocombustível e, a utilização de antioxidantes naturais corrobora com seu caráter biodegradável e sustentável. Neste trabalho verificou-se o potencial antioxidante do extrato metanólico das folhas da Tabernaemontana catharinensis, conhecida vulgarmente como cobrina, frente ao biodiesel de soja. Ao misturar biodiesel com o extrato de cobrina em uma determinada concentração observou-se uma variação no período de indução prolongando a estabilidade oxidativa do mesmo. O presente aditivo natural, extrato de cobrina e cobrina potencializado com ácido cítrico, ácido ascórbico e -tocoferol é considerado ecologicamente correto, não tóxico, biodegradável e renovável e antioxidante para biodiesel, com a capacidade de aumentar o tempo de indução de biodiesel em valores iguais ou superiores à 8h como descrito nas normas da ANP 2017. / Biodiesel, besides a market character, have a social and environmental basis, and can be considered a renewable energy source with diversification of feedstock and means of production. To be commercialized, biodiesel must meet the quality specifications established by the ANP as Oxidative stability, what is directly related to the composition in fatty acids, of the feedstock used. In particular, the presence of unsaturated fatty acids directly interferes with the oxidative stability of the biodiesel because through the multiple bonds the oxidation reactions take place. The use of antioxidant additives is an alternative to increase the stability of biofuel and the use of natural antioxidants corroborates its biodegradable and sustainable character. In this work the antioxidant potential of the methanolic extract of the leaves of Tabernaemontana catharinensis, commonly known as Cobrina was verified in soybean biodiesel. When mixing biodiesel with the Cobrina extract at a certain concentration a variation in the induction period was observed prolonging the oxidative stability of the same. This natural additive, Cobrina extract and Cobrina extract enhanced with citric acid, ascorbic acid and α-tocopherol is considered to be environmentally friendly, non-toxic, biodegradable and renewable and antioxidant for biodiesel. With the capacity to increase the time of induction of biodiesel in values equal to or greater than 8h as described in ANP 2017 standards. Key words: Natural antioxidant, Oxidative stability, Cobrina
6

Óleo degomado de grãos de soja sem defeitos e partidos para produção de biocombustível

Miranda, Eduardo Lebarbenchon de 28 February 2018 (has links)
Submitted by Eunice Novais (enovais@uepg.br) on 2018-07-24T17:40:36Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) EDUARDO L. MIRANDA.pdf: 667563 bytes, checksum: a26ce019073169bce213e38345cf54b2 (MD5) / Made available in DSpace on 2018-07-24T17:40:36Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) EDUARDO L. MIRANDA.pdf: 667563 bytes, checksum: a26ce019073169bce213e38345cf54b2 (MD5) Previous issue date: 2018-02-28 / A demanda por energia no mundo está cada vez mais crescente. Uma alternativa é a produção de biodiesel de soja, que além dar um destino ao subproduto do grão também é fonte de energia renovável. As indústrias de biodiesel seguem padrões de classificação de grãos, onde realizam descontos para grãos avariados em casos de ultrapassagem dos limites pré-estabelecidos pelas normas. O objetivo desse trabalho foi verificar se os descontos normatizados para grãos avariados procedem; comparando a qualidade do óleo para produção de biodiesel proveniente de grãos de soja (Glycine max) classificados como partidos e sem defeitos. O delineamento experimental utilizado foi o inteiramente aleatorizado. Os tratamentos consistiram nas análises de óleo degomado de grãos partidos e sem defeitos de dez cultivares de soja. Foram realizadas três repetições por tratamento. As variáveis analisadas foram: acidez, índice de estabilidade oxidativa do óleo e o teor de óleo de grãos. Concluiu-se que a qualidade do óleo de soja para produção de biodiesel, proveniente de grãos de soja classificados como sem defeitos e partidos diferiu significativamente em mais de 70% das dez cultivares testadas. Os resultados foram semelhantes apenas para uma das cultivares analisadas (NA 5909 16/17) em duas variáveis (acidez e índice de estabilidade oxidativa) e diferindo para o teor de óleo. / The world’s demand for energy is constantly increading. One of the alternatives is the production of the biodiesel from source of soy. The biodiesel from the soy provides the benefits of being a great use of the grain itself, and also is a great source of renewable energy. The industry follow specific standards to classify the quality of the grains. In case the grains present results outside of the standards estipulated by the industry, a discount is determined to buy the cargo. The purpose of this study is to verify and analize the discount established by the industry for the gain of soy (Glycine max), comparing the quality of the oil for the purpose of production of biodiesel classified as “broken” and/or without any defects. The experimental design used for statistics purposes was the Entirely Randomized. The study analized the degummed oil in the production of ten diferente samples of biodiesel from gain of soy “broken” and without any deffects. The variables analized were: acidity, oil oxidative stability index, and grain oil content. The conclusion presented results comparing both qualities of the grain of soy (i.e. “broken” and without any defects), showing a discrepancy of 70% in the quality index, analizing the ten different samples randomly extracted and tested. The results were similar only for one of the analyzed cultivars (NA 5909 16/17) in two variables (acidity and oxidative stability index) and differing for the oil content.
7

Extração de oleuropeína de folhas de oliva com solvente hidroalcoólico e efeito dos extratos sobre a estabilidade oxidativa de óleos vegetais / Oleuropein extraction of olive leaves using hydroalcoholic solvent and effect of the extracts on the oxidative stability of vegetable oils

Coppa, Carolina Fernanda Sengling Cebin 30 March 2016 (has links)
A oleuropeína é o composto fenólico mais abundante presente nas folhas da oliveira, sendo que muitos estudos vêm demonstrando que este composto apresenta importantes propriedades antimicrobiana, antioxidante, anti-inflamatória, entre outras, surgindo o interesse em estudos de métodos para sua extração e aplicação em produtos na área alimentícia, cosmética e farmacêutica. O objetivo deste estudo foi a extração da oleuropeína à partir de folhas de oliva, utilizando solvente não tóxico, para posterior aplicação dos extratos em óleos vegetais a fim de se verificar seu efeito sobre a estabilidade oxidativa dos mesmos. O solvente selecionado para o estudo foi uma mistura de etanol e água (70:30, em massa, condição obtida através de um trabalho prévio), na presença de 1 % de ácido acético. Em uma primeira etapa, foram realizados experimentos de extração utilizando-se as técnicas de maceração (tipo I) e ultrassom (tipo II), em diferentes condições de temperatura (20, 30, 40, 50 e 60°C). Em uma segunda etapa, através de experimentos com maceração à temperatura ambiente, estudou-se o efeito da razão folhas:solvente (1:8, 1:6 e 1:3) e a influência da presença de ácido acético sobre o processo de extração (tipo III). Por fim, realizando-se a maceração na presença de ácido acético, temperatura ambiente e proporção folhas: solvente igual a 1:3, realizaram-se extrações sequenciadas a partir de uma mesma matéria-prima (tipo IV). Os resultados desses experimentos foram expressos em rendimento de oleuropeína (RO), teor de oleuropeína nos extratos (TO) e rendimento global (RG). Analisando-se os experimentos I e II, verificou-se que a temperatura não exerceu influência significativa sobre as respostas RO, TO e RG. Além disso, verificou-se que os valores das respostas para os experimentos com a maceração foram um pouco maiores do que os valores obtidos para as extrações com o auxílio do ultrassom. Nos experimentos tipo III, em linhas gerais, observou-se a influência positiva da presença do ácido acético sobre as respostas estudadas. Verificou-se também que, na presença de ácido, o aumento da quantidade de solvente na extração conduz ao aumento de RO e RG, e à diminuição de TO. Através do experimento tipo IV, constatou-se que mesmo após quatro extrações sequenciadas, ainda não foi possível esgotar a oleuropeína da matéria-prima. Após a obtenção de todos os extratos hidroalcoólicos, selecionou-se um contendo aproximadamente 19 % de oleuropeína para o estudo da estabilidade oxidativa em óleos vegetais (oliva e girassol) utilizando o método Rancimat. A presença de extrato aumentou em 3 horas o tempo de indução do azeite de oliva extra-virgem, e em 2 horas o tempo de indução do azeite de oliva comum. Os óleos de girassol bruto e refinado não apresentaram melhora na estabilidade oxidativa quando adicionados dos extratos. Foram realizados também testes de estabilidade oxidativa através da adição direta de folhas de oliva em pó nos azeites de oliva extra-virgem e comum. Para o azeite extra-virgem, a adição das folhas não proporcionou melhora da estabilidade oxidativa, porém para o azeite comum, houve um aumento de mais de 2 horas no tempo de indução.Os resultados apresentados neste trabalho demonstraram que é possível obter extratos contendo teores significativos de oleuropeína utilizando-se um solvente renovável. Além disso, constatou-se que os mesmos podem ser utilizados como um antioxidante natural em azeite de oliva, melhorando sua estabilidade oxidativa. / Oleuropein is the most abundant phenolic compound present in the leaves of the olive tree, and many studies have shown that this compound has significant antimicrobial properties, antioxidant, anti-inflammatory, among others, emerging interest in studies of methods for extraction and use in products in the food industry, cosmetics and pharmaceuticals. The aim of this study was the extraction of oleuropein from the olive leaf, using non-toxic solvent, for further application of the extracts in vegetable oils in order to check its effect on their oxidative stability. The solvent selected for the study was a mixture of ethanol and water (70:30, % mass, condition obtained from a previous study), in the presence of 1 % acetic acid. In a first step, extraction experiments were conducted using maceration (type I) and ultrasound (type II) under different temperature conditions (20, 30, 40, 50 and 60 ° C). In a second step, through experiments with maceration at room temperature, the effect of the ratio olive leaves:solvent (1:8, 1:6 and 1:3) and the influence of the presence of acetic acid on the process of extraction (type III) was studied. Finally, using maceration in the presence of acetic acid at room temperature and proportion olive leaves:solvent of 1:3, sequencial extractions from the same raw material (type IV) were performed. The results of these experiments were expressed in oleuropein yield (RO), oleuropein content in extracts (TO) and global yield (RG). Analyzing the experiments I and II, it was found that the temperature did not have significant influence on the RO, TO and RG values. Furthermore, it was found the response values for the experiments with maceration was somewhat higher than values obtained for extractions using ultrasound. In type III trials, in general, a positive influence of the presence of acetic acid in the studied answers were observed. It was also found that in the presence of acid, higher amount of solvent leads to an increase of RO and RG values, and a decrease of TO value. Through the experiment type IV, it was found that even after four sequential extractions, it was not possible to exhaust oleuropein raw material. After obtaining all the hydroalcoholic extracts, na extract contanining approximately 19 % of oleuropein was selected for the study of oxidative stability of vegetable oils (olive and sunflower oil), using the Rancimat method. The presence of extract increased in 3 hours the induction time of extra-virgin olive oil, and in 2 hours the induction time of common olive oil. Crude and refined sunflower oils showed no improvement in the oxidative stability when added to the extracts. Oxidative stability tests were also performed by direct addition of olive leaf powder in extra virgin and common olive oil. For extra virgin olive oil, the addition of the powder leaves did not improve the oxidative stability, but for the common oil, an increase of more than 2 hours in induction time was observed. Results demonstrated that it is possible to obtain extracts containing significant concentrations of oleuropein using a renewable solvent. Furthermore, it was found that it can be used as a natural antioxidant in olive oil, improving its oxidative stability.
8

Oxidative Stability of Omega-3 Polyunsaturated Fatty Acids Enriched Eggs

Ren, Yuan 11 1900 (has links)
Omega-3 polyunsaturated fatty acids (n-3 PUFA) enriched eggs are an increasingly important contributor to the egg industry due to the health benefits of n-3 PUFA. During storage and cooking, n-3 PUFA could undergo oxidation and further cause cholesterol oxidation. This study examined stability of n-3 PUFA enriched eggs fortified with antioxidants (vitamin E or organic Selenium [Sel-Plex] or both) following storage and cooking. Total n-3 PUFA was not affected by cooking and storage, although long chain n-3 PUFA concentration decreased. Overall, both vitamin E and Sel-Plex decreased oxidation of yolk lipids and cholesterol. Cooking increased the lipid and cholesterol oxidation. Four weeks of storage did not affect the cholesterol oxidation products (COPs) content, but increased lipid oxidation. It is possible to make the n-3 PUFA in enriched eggs more stable with dietary antioxidants. / Food Science and Technology
9

Encapsulation of flaxseed oil within modified lentil protein isolate matrices

2013 March 1900 (has links)
The overarching goal of this research was to formulate an encapsulated powder using a modified lentil protein isolate-maltodextrin mixture to encapsulate flaxseed oil by freeze drying. The primary objectives were: a) to examine the physicochemical and emulsifying properties of lentil protein isolates with different degrees of hydrolysis; b) to design and test the physicochemical properties of encapsulated flaxseed oil using a wall material with native, heat treated and partially hydrolyzed lentil proteins in combination with maltodextrin; and c) test the oxidative stability of encapsulated flaxseed oil with the capsule design with the lowest surface oil and highest encapsulation efficiency versus free oil. During the first study, the physicochemical and emulsifying properties of lentil protein isolates (LPI) were investigated as a function of their degree of hydrolysis (DH of 4, 9 and 20%) following exposure to trypsin/heat. Interfacial tension, surface characteristics (charge and hydrophobicity) and intrinsic fluorescence were determined and related to changes in the emulsification activity (EAI) and stability indices (ESI) of unhydrolyzed (u-LPI) and hydrolyzed LPI (h-LPI) in a flaxseed oil-water emulsion. Most importantly surface hydrophobicity declined from ~30 to ~24 for the u-LPI and h-LPI (DH 4-20%), respectively. The changes in physicochemical properties induced by hydrolysis had a detrimental effect on EAI and ESI values, which declined from ~51 to ~47 m2 g-1 and ~12 to ~ 11 min for u-LPI and h-LPI (DH 4-20%), respectively. In the second study, the physicochemical properties of encapsulated flaxseed oil within lentil protein-based maltodextrin microcapsules were investigated using native (n-LPI), pre-treated (heated, un-hydrolyzed (u-LPI); and heated, hydrolyzed (h-LPI)) lentil protein isolates and as a function of oil load (10.0, 20.0 and 30.0% of total solids). The moisture, water activity, surface oil and encapsulation efficiency (EE) were assessed, along with droplet size and emulsion morphology. Light microscopy imaging of the emulsions, showed that the h-LPI had slightly larger oil droplets than the n-LPI and u-LPI, which both appeared similar. Microcapsules prepared from h-LPI showed significantly higher surface oil and lower EE than both the n-LPI and u-LPI materials. The microcapsules prepared using n-LPI with 10.0% oil loading were found to have the lowest surface oil content (~3.7%) and highest EE (~62.8%) for all formulations, and were subjected to an oxidative storage stability test over a 30 d period vs. free oil. The encapsulation process however induced autooxidation leading the production of a greater amount of primary oxidative products than free oil. Findings indicate that future studies are necessary to enhance the stability of the flaxseed oil through the encapsulation process.
10

Evaluation of Xanthan/Enzymatically Modified Guar Gum Mixtures in Oil-in-Water Emulsions

Chityala, Pavan Kumar 01 July 2015 (has links)
Oil-in-water emulsions have wide range of applications in food industry because of their structure-forming properties, and as delivery systems of polyunsaturated fatty acids into foods. The thermodynamic instability of oil and water, and high susceptibility of unsaturated fatty acids to oxidation lead to physical and oxidative stability in oil-in-water emulsions. These instability processes are generally controlled by incorporating proteins and polysaccharides into oil-in-water emulsions. The objective of this study was to evaluate xanthan/enzymatically modified guar (XG/EMG) polysaccharides on the physical and oxidative stability of 2 wt% whey protein stabilized oil-in-water emulsions containing 20% v/v menhaden fish oil. Enzymatic modified guar gum was obtained by hydrolyzing native guar gum using α-galactosidase enzyme. Emulsions were prepared for guar gum (GG), xanthan gum (XG), xanthan/guar (XG/GG), and xanthan/enzymemodified guar (XG/EMG) gum mixtures using 0, 0.05, 0.1, 0.15, 0.2, and 0.3% gum concentrations. Emulsions were then evaluated for creaming, viscosity, particle size, and microstructure to evaluate the physical stability, and peroxide value, TBARS value and GC-MS solid phase micro extraction (SPME) experiments were performed to evaluate the oxidative stability. Emulsions containing XG/EMG gum mixtures exhibited better creaming stability and higher viscosity of all the emulsion types. However, XG/EMG gum concentrations did not affect the droplet size of the emulsions. The microstructures revealed decreased flocculation in emulsions with XG/EMG mixtures. The primary and secondary lipid oxidation measurements indicated that emulsions containing XG/EMG gum mixtures were more effective in preventing the lipid oxidation of all the emulsion types. From the results, it is evident that XG/EMG gum mixtures can be used as emulsifiers in oil-in-water emulsions to increase both physical and oxidative stability.

Page generated in 0.0561 seconds