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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.
1

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.
2

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.
3

Oxidative Stability of Omega-3 Polyunsaturated Fatty Acids Enriched Eggs

Ren, Yuan Unknown Date
No description available.
4

Barley protein based microcapsules for nutraceutical delivery

Wang, Ruoxi Unknown Date
No description available.
5

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.
6

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.
7

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
8

Barley protein based microcapsules for nutraceutical delivery

Wang, Ruoxi 06 1900 (has links)
Barley protein based microcapsules (1-5µm) incorporating fish oil/β-carotene were successfully prepared. Well suspended solid microcapsules, rather than emulsions, were able to form after high pressure emulsifying process. These wet-status microcapsules could be turned into dry powder by a spray drying process. The microcapsules demonstrated spherical shape and high loading capacity. Oxidative stability tests under accelerated conditions and in food formulations suggest barley proteins are effective microencapsulation materials to protect fish oil against oxidation. Microcapsule degradation and bioactive compound release behaviors were studied in the simulated gastro-intestinal tract. The data revealed that nano-encapsulations (20-30nm) were formed as a result of enzymatic degradation of microcapsule bulk matrix in the simulated gastric tract. These nano-encapsulations delivered β-carotene to a simulated human intestinal tract intact, where they were degraded by pancreatic enzymes and steadily released the β-carotene. These uniquely structured microcapsules may provide a new strategy to develop target delivery systems for nutraceuticals / Food Science and Technology
9

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
10

Goma de soja: uma alternativa de emulsificante para dietas de poedeiras comerciais / Soy gum: an emulsifying alternative for diets of laying hens

Souza, Rosemary Pereira de Pedro [UNESP] 03 March 2017 (has links)
Submitted by ROSEMARY PEREIRA DE PEDRO SOUZA null (rosemaryppsouza@gmail.com) on 2017-04-07T21:23:24Z No. of bitstreams: 1 Dissertação - Rosemary P. de P Souza 07-04.pdf: 1118611 bytes, checksum: 9417b9cfa0ee4b0a1002991a20e5a5f8 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-17T14:40:37Z (GMT) No. of bitstreams: 1 souza_rpp_me_ilha.pdf: 1118611 bytes, checksum: 9417b9cfa0ee4b0a1002991a20e5a5f8 (MD5) / Made available in DSpace on 2017-04-17T14:40:37Z (GMT). No. of bitstreams: 1 souza_rpp_me_ilha.pdf: 1118611 bytes, checksum: 9417b9cfa0ee4b0a1002991a20e5a5f8 (MD5) Previous issue date: 2017-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O experimento foi conduzido no Setor de Avicultura da Universidade Estadual Paulista – UNESP, Faculdade de Engenharia de Ilha Solteira, com a finalidade de avaliar o efeito da inclusão de níveis crescentes de goma de soja (0, 1, 2, 3, 4 e 5%) na alimentação de poedeiras comercias, e verificar a viabilidade econômica de sua utilização como mais um produto comercial derivado da soja. Foram utilizadas 180 poedeiras comerciais leves da linhagem Lohmann, com 40 semanas de idade, durante o período de 112 dias (quatro ciclos de 28 dias), distribuídas em um delineamento inteiramente casualizado, totalizando 6 tratamentos com 5 repetições (6 aves por parcela). No experimento foram avaliados dados de parâmetros zootécnicos: porcentagem de postura (ave/dia), consumo de ração (g/ave/dia), peso dos ovos (g), conversão alimentar (kg/kg), qualidade interna e externa dos ovos e estabilidade oxidativa dos ovos. No que se refere aos parâmetros de desempenho a inclusão de 5% de goma na dieta aumentou o consumo de ração e a maior produção de ovos foi observada nos tratamentos com a inclusão de 3 e 5% de goma. Quanto ao peso médio dos ovos e massa de ovos a inclusão de goma a partir de 3% favoreceu o aumento dos mesmos. Para os parâmetros de qualidade dos ovos os tratamentos com 4 e 5% de goma foram os que apresentaram os menores valores de unidade Haugh, o aumento da coloração da gema ocorreu a partir da inclusão de 3% de goma. A estabilidade oxidativa dos ovos apresentou diferença (P<0,05) apenas para os ovos provenientes do tratamento com 4% de goma armazenados sob refrigeração por 21 dias. A análise econômica mostrou maior retorno econômico com a inclusão de apenas 1% de goma de soja na dieta. / The experiment was carried in the Poultry Sector of the Universidade Estadual Paulista - UNESP, Ilha Solteira Campus, in order to evaluate the effect of inclusion of increasing levels of soy gum (0, 1, 2, 3, 4 and 5 %) In the feeding of commercial laying hens, and verify the economic viability of this use as another commercial product derived from soybean. The study used 180 Lohmann commercial laying hens with 40 week old Lohmann commercial laying hens during the period of 112 days (four cycles of 28 days), distributed in a completely randomized design, totaling 6 treatments with 5 replicates (6 birds per plot). The evaluated parameters were feed intake (g/bird/day), egg weight (g), feed conversion (kg/kg), internal and external egg quality and oxidative stability of eggs. Regarding the performance parameters, the inclusion of 5% gum in the diet increased the feed intake and, the higher egg production was observed in the treatments with the inclusion of 3 and 5% of soy gum. Regarding the average egg weight and egg mass, the inclusion of soy gum from 3% favored their increase. For egg quality parameters treatments with 4 and 5% of soy gum were the ones with the lowest values of Haugh unit, the increase of the color of the yolk occurred from the inclusion of 3% of gum. The oxidative stability of the eggs presented a difference (P<0.05) only for the eggs from the treatment with 4% of gum stored under refrigeration for 21 days. The economic analysis showed a higher economic return with the inclusion of 1% of soy gum in the diet.

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