• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 22
  • 19
  • 9
  • 9
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 76
  • 23
  • 20
  • 18
  • 17
  • 12
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 7
  • 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

Extrato de bagaço de uva como antioxidante natural em carne de frango processada e armazenada sob congelamento / Grape pomace extract as natural antioxidant in processed chicken meat stored under freezing

Miriam Mabel Selani 19 May 2010 (has links)
A carne de frango, em razão da elevada concentração de ácidos graxos insaturados, é altamente suscetível ao processo de oxidação lipídica, que afeta sabor, aroma, cor e textura dos alimentos, limitando sua estabilidade e vida-útil. Devido à possível toxicidade dos antioxidantes sintéticos e à demanda atual por produtos mais saudáveis, o uso de antioxidantes naturais, como o extrato de semente e casca de uva, representa uma alternativa na prevenção da oxidação lipídica em carne de frango, além de permitir aproveitamento do resíduo do processamento do vinho e suco de uva. Assim, o objetivo deste trabalho foi avaliar extratos de bagaço de uva (sementes e cascas) das variedades Isabel e Niágara (Vitis labrusca L.) quanto à atividade antioxidante em carne de frango processada crua e cozida. Foram adicionados à carne de frango 4 tipos de antioxidantes: butilhidroxitolueno; mistura comercial de eritorbato de sódio, ácido cítrico e açúcar; extrato de semente e casca de uva Isabel; extrato de semente e casca de uva Niágara; além do tratamento controle, sem antioxidante. A carne de frango foi processada no formato de mini-hambúrgueres, embalada a vácuo e armazenada sob congelamento (-18°C), durante 9 meses. As amostras foram caracterizadas através da determinação da composição centesimal. A cada três meses, foram realizadas análises de pH, cor instrumental, avaliação microbiológica, oxidação lipídica (valor das substâncias reativas ao ácido tiobarbitúrico TBARS) e análise sensorial. Não foi verificada alteração significativa (p>0,05) na composição centesimal e no valor de pH de amostras cruas e cozidas, em nenhum dos tratamentos analisados. Ambos os extratos de bagaço de uva mostraram efeito na inibição da oxidação lipídica da carne de frango crua e cozida, apresentando resultados comparáveis aos antioxidantes sintéticos utilizados. Houve interferência dos extratos de bagaço de uva na coloração da carne de frango cozida. Na análise de cor objetiva, os tratamentos com extrato de semente e casca de uvas Isabel e Niágara apresentaram-se mais escuros, menos avermelhados e com menor intensidade de cor amarela e, na análise subjetiva, as notas destes tratamentos, para o atributo alteração de cor, foram significativamente maiores (p<0,05) que as dos demais tratamentos. A coloração da carne de frango crua não foi afetada pela adição dos extratos. Através da análise sensorial, o extrato de bagaço de uva Isabel causou menor alteração no sabor e odor da carne de frango, apresentando resultados semelhantes aos antioxidantes sintéticos. Os resultados da análise microbiológica indicaram que as amostras de todos os tratamentos apresentaram-se dentro dos padrões estabelecidos pela legislação brasileira. A utilização de bagaço da indústria vinícola (semente e casca) como antioxidante natural, combinado com o uso da embalagem a vácuo e armazenamento congelado, pode ser considerada um método eficiente para retardar a oxidação lipídica de carne de frango processada, tanto crua, como cozida. Entretanto mais estudos devem ser conduzidos a fim de aprimorar a compatibilidade dos extratos ao produto, buscando minimizar suas interferências nas características sensoriais e organolépticas. / Chicken meat, due to the high concentration of unsaturated fatty acids, is highly susceptible to lipid oxidation, which affects taste, aroma, colour and texture of foods, limiting its stability and shelf-life. Due to the possible toxicity of synthetic antioxidants and the current demand for healthier products, the use of natural antioxidants, such as grape seed and peel extract, is an alternative in the prevention of lipid oxidation in chicken meat, and allows the use of residues from wine and grape juice processing. Thus, the objective of this study was to evaluate grape pomace extracts (seeds and peels) of Isabel and Niagara varieties (Vitis labrusca L.) on the antioxidant activity in raw and cooked processed chicken meat. Four types of antioxidants were added to chicken meat: butylhydroxytoluene; commercial mixture of sodium erythorbate, citric acid and sugar; Isabel grape seed and peel extract; Niagara grape seed and peel extract; and the control, without antioxidant. The chicken meat was processed in the form of mini-burgers, vacuum packaged and stored under freezing (-18°C) for 9 months. The samples were characterized by determining the proximate composition. Every three months, the following analyses were carried out: pH, instrumental color, microbiological evaluation, lipid oxidation (value of thiobarbituric acid reactive substances - TBARS) and sensory analysis. No significant changes (p>0.05) in proximate composition and pH values were observed for raw and cooked samples, in none of the treatments. Both grape pomace extracts showed effect on inhibiting lipid oxidation in raw and cooked chicken meat, with results comparable to synthetic antioxidants used. There was interference from grape pomace extracts in the color of cooked chicken meat. In the objective color analysis, Isabel and Niagara grape seed and peel extract treatments were darker, less red and with less intense yellow color, and in the subjective analysis, the scores for these treatments, for attribute color alteration, were significantly higher (p<0.05) than the other treatments. The color of raw chicken meat was not affected by the addition of extracts. Through sensory evaluation, the Isabel grape pomace extract caused less change in taste and odour of chicken meat, with results similar to synthetic antioxidants. The results of microbiological analysis indicated that samples from all treatments were within the standards established by Brazilian legislation. The use of pomace from the wine industry (seeds and peels) as natural antioxidant, combined with the use of vacuum packaging and frozen storage, can be considered an effective method to retard lipid oxidation in processed chicken meat, both raw and cooked. However, further studies should be conducted in order to improve the compatibility of the extracts to the product, aiming to minimize its interference in the sensorial and organoleptic characteristics.
22

Možnosti mikrobiální degradace a využití odpadů z potravinářských výrob / Prospects of Microbial Degradation and Waste Utilization from Food Processing Industry

Illková, Kateřina January 2012 (has links)
This work deals with the problem of microbial degradation of the waste materials from food industry. This work is focused on the production of technological significant enzymes producing by microorganisms, which were able to use the waste as a sole carbon source. In the first part of this work, the attention was focused on the production of pectolytic enzymes. This part was made within study interships in Slovak Academy of Sciences, department of Glycomics in Bratislava. The grape pomace as the waste form winegrowing was used as a sole carbon source for microbial growth and enzymes production. The production of pectolytic enzymes was tested on this waste. After screening the most suitable microorganisms was chosen with the highest production of polygalacturonase activity. Produced enzymes were isolated by extraction techniques, purified and then identified proteomically. The aim of the second part of this work was the waste water treatment containing lipids and lipolytic enzymes. The reason was the cooperation with the company constructing grease traps. The characterization of supplied commercial preparations was the subject of this work and the other reason was the characterization of conditions for lipases secreting by microorganisms, identification of microorganisms present in the commercial preparation and testing of new microbial cultures for the development of new preparation for the grease traps.
23

Multivalorizaiton of beverage industry waste streams for the development of bioplastics and food ingredients

Williamson, Kathryn January 2021 (has links)
No description available.
24

Investigation of the binding effect of fungal fiber (grown on apple pomace) in the formation of lyocell nonwoven textiles and their potential applications

Luo, Xue January 2021 (has links)
This project combines nonwoven technology, biological technology and food waste management and seeks for this feasibility to use fungal microfiber (FM) as a binder for lyocell pro-duction and the characterizations for possible applications. Rhizopus delemar was cultivated apple pomace in liquid-state fermentation to obtain mycelia biomass. The biomass was later blended in a kitchen blender for one minute. The blended FM was later mixed with 6 mm lyocell fibre at different FM dry weight percentage and water to make nonwoven webs by wet-laid method. The feasibility of using fungal microfiber as a binder for lyocell nonwovens was confirmed in this study. It is not possible to make nonwoven webs using lyocell short fibre without any binder applied. With 5%_FM, the tensile strength of lyocell nonwoven webs reached 0.0989 MPa. A clear increasing tensile strength was recorded as the increasing of FM weight per-centage and resulted a highest tensile strength at 9.38 MPa when applying 60%_FM. The re-sult of water contact angle proved that the increasing FM could decrease the hydrophobicity of nonwoven samples. Abrasion test showed that FM could improve the abrasion resistance of the lyocell nonwoven samples. Porosity test showed that lyocell nonwoven samples with a higher FM ended up with smaller mean flow pore size diameter (MFP) that nonwoven samples with 65%_FM has an average MFP at 7.26 m m. The SEM images reviled that FM bonded nonwoven webs had a fibrous structure, which is due to binding effect of fungal microfiber on lyocell short fibers. These characterizations have demonstrated the mechanism of using fungal microfiber as a binder for lyocell nonwovens in this project. In this thesis project, FM bonded lyocell nonwoven webs showed a great potential on the application of nonwoven applications such as interior materials or filtration materials.
25

Production of textile fibres from filamentous fungi grown on apple pomace : invertase pre-treatment

Berg, Sofia January 2023 (has links)
In this work Rhizopus Delemar was grown on an apple pomace medium, a waste product from the juice industry. The apple pomace was pre-treated with the enzyme invertase to hydrolyse the sucrose available in the waste to glucose and fructose, which are digestible by the fungus. Combination of invertase pre-treatment and yeast extract supplementation, resulted in highest biomass growth which was 4.3 ± 0.5 g/l biomass. The fungal cell wall was separated from fungal biomass using an alkali treatment. A hydrogel was formed from the cell wall material and used for spinning of filaments using dry gel spinning. The average dry weight percentage of the gel was 11.6 ± 1.3 %. The gel was spun through a needle to a collecting rotating surface to make filaments. The filaments were easy to spin and to collect continuous fibres. The spun filaments had a rubber-like texture. All the tested filaments had an ultimate tensile strength approximately 2-3 MPa and 10 – 12% elongation at break. The conclusion of this work is that it is possible to produce fibers from fungi grown in apple waste and that it is possible to improve fungal growth using invertase and yeast extract. The tensile strength of the filaments needs further improvement to compete with other materials used in woven fabrics.
26

Insects as a Sustainable Food Ingredient – Utilization of Carrot Pomace, Identification of Early Adopters, and Evaluation of Mealworm Acceptability

Rovai, Dominic 01 June 2021 (has links) (PDF)
Insects have been proposed as a sustainable alternative to livestock to help feed the growing population. Edible insects such as mealworms require less land and resources and can utilize food by-products to grow. While insects are consumed by over 2 billion people worldwide, they are not widely accepted in developed countries like the United States because of their unfamiliarity and the perception of disgust associated with entomophagy. The objectives of this research are to 1) grow mealworms using carrot pomace and determine an optimum diet for growth and nutritional composition, 2) identify and classify early adopters of insects, and propose a product form, and 3) assess the acceptability of frozen, ready-to-cook mealworms with early adopters. A response surface design was used to evaluate the use of carrot pomace in various percentages in the substrate and as the moisture source in a mealworm growing system. Mealworms were grown under controlled conditions in a climate chamber until they began to pupate, and statistical models were fitted to predict mealworm mortality, weight, days to pupation, protein content, fat content, and moisture content. An algorithm in Design Expert was used to optimize mealworm growth based on maximizing mealworm weight and minimizing mortality and days to pupation, and the optimum diet was found to be 36% carrot pomace in the substrate with carrot pomace as the moisture source. Early adopters of insects were identified through a survey using Red Jade Sensory Software. Participants were segmented using partitioning around medoids clustering algorithm based on responses to questions on willingness to consume insects in a variety of forms. Four segments were identified: No-thank-you’s, Hideaways, Daredevils, and Peekaboo’s. Daredevils, Peekaboo’s, and Hideaways are early adopters of insects in the nonvisible form, and Daredevils and Peekaboo’s are also early adopters of insects in the visible form. Based on these insights, frozen, ready-to-cook mealworms were selected to target Daredevils and Peekaboo’s as a product to serve as a sustainable alternative to traditional livestock protein. Participants from each of the four segments were shown a video of mealworm cooking and asked their willingness to buy the product and the motivation behind their response. The majority of respondents were unwilling to buy this product, driven by unfamiliarity and the perception of disgust. However, over half of Daredevils were willing to buy the product, driven by the novelty and ease of preparation. Marketing a product towards this group may be a feasible route for entry into the market and increase the familiarity of edible insects, thereby contributing to long-term acceptability.
27

Use of Naturally Occurring Anthelmintics to Control Gastrointestinal Parasites in Small Ruminants

LeShure, Shirron Nicole 16 September 2014 (has links)
No description available.
28

Integrated Process Design and Techno-Economic Analysis of A Grape Pomace Biorefinery

Jin, Qing 09 September 2020 (has links)
Grape pomace (GP) is one of the most abundant and underutilized fruit-derived wastes. GP is generated during winemaking, occupying over 60% of the total solid winery wastes. GP may cause serious environmental problems if it is not properly handled. On the other hand, it is rich in valuable compounds that are worthy of recovery. Although research has been working on GP upgrading, the utilizations are limited to producing a single product (e.g., grape seeds oil or polyphenol powders), which leads to large volumes of secondary wastes left. Therefore, the goal of this study is to develop an integrated process for the comprehensive utilization of GP by the production of multiple value-added products and evaluate its economic feasibility at a commercial scale. First, the chemical composition of different industrial GPs was analyzed to lay the foundation for the process design. Based on the analyzed chemical composition, an integrated process was developed to produce grape oil, polyphenols, and biofuels from GP. In this process, GP was extracted by hexane to produce oil, followed by aqueous ethanol solution extraction to obtain polyphenols. The solid residue rich in structural carbohydrates was then pretreated by alkali to partially remove lignin and enzymatically hydrolyzed to produce monomer sugars. The produced sugars were used as feedstock to produce acetone, butanol and ethanol (ABE) through anaerobic fermentation. Under the optimized conditions, the process was able to produce 71.9 g crude oil, 322.8 g crude polyphenols (equivalent to 72.6 g gallic acid), and 20.7 g ABE from 1 kg dry GP. Besides the valuable products, the process co-generated a large amount (50% of input GP biomass) of secondary waste, which is rich in lignin. Therefore, we further converted the secondary waste to biochars and evaluated their potential application in water purification by removing lead (Pb) from contaminated water. Based on the results, the produced biochar showed a high Pb adsorption ability (134 mg/g), with 66.5% of lead removal achieved within the first 30 min. Experimental and modeling results indicated that both physisorption and chemisorption mechanisms were involved in the Pb adsorption of the biochar. Finally, techno-economic analysis was conducted to evaluate the economic feasibility of the integrated processing of GP into oil, polyphenols, and biochar at an industrial scale. The results showed that compared with generating of single product or dual products, the integrated process aiming to produce multiple products had the best economic performance with the net present value (NPV), internal rate of return (IRR), and payback period of $135.0 million, 47.5%, and 1.8 years, respectively. Sensitivity analysis showed that plant capacity and polyphenol selling price had major impacts on process economics. Therefore, a suggestion for implementing this integrated process is to invest more in the polyphenol production and purification process to generate high-quality polyphenols with a high selling price and running the plant with a large capacity. Overall, we explored a novel integrated process that aims to produce multiple value-added products to increase the economic gain for the wine industry, and at the same time, potentially reduce the environmental burdens caused by GP disposal. / Doctor of Philosophy / During wine making, a large amount of solid waste is generated, and the major one is called grape pomace (GP). GP is mainly consisted of grape skins, seeds, and some stems. Normally, GP is discarded as waste; however, if it is not handled properly, GP may cause serious damages to the environment such as contaminating soil and stream water. On the other hand, GP has valuable compounds that could be recovered for other applications. Previous researchers used GP to produce a single product, which still leads to a large amount of components not used. Therefore, the aim of the current study is to design a process to comprehensively utilize GP to produce multiple value-added products. The developed process can produce grape seed oil, polyphenols, and biofuels from GP. The solid residue generated from the designed process was further converted into biochar, which can be used as an excellent adsorbent to remove lead (Pb) from contaminated water. Based on the economic model results, the developed process to convert GP into grape seed oil, polyphenols, and biochar could be a promising investment at an industrial scale. Generally speaking, various valuable products were obtained from low value GP waste, which could not only reduce the potential environmental problems caused by waste disposal, but also provide different value-added products for food, pharmacy, chemical, and energy industries.
29

Funkcionalni proizvodi na bazi cerealija i pseudocerealija sa dodatkom inkapsuliranog ekstrakta tropa cvekle / Cereal- and pseudocereal-based functional products with encapsulated beetroot extract

Jakišić Mirjana 23 December 2020 (has links)
<p>U okviru disertacije kreirani su novi, nutritivno obogaćeni, fini pekarski proizvodi na bazi bra&scaron;na od cerealija i pseudocerealija, kroz čiju se proizvodnju valorizuju sporedni proizvodi prehrambene industrije &ndash; trop cvekle. Rezultati istraživanja pružaju nova saznanja o stepenu redukcije bioaktivnih jedinjenja (polifenola i betalaina) tokom postupka proizvodnje i skladi&scaron;tenja finih pekarskih proizvoda obogaćenih ekstraktom tropa cvekle, kao i njihov uticaj na reakcije neenzimskog tamnjenja.<br />Uspe&scaron;no realizovana istraživanja ukazala su na stepen stabilinosti bioaktivnih jedinjenja iz tropa cvekle inkapsulacijom na protein soje i na opravdanost primene ove metode (tehnike) u proizvodnji funkcionalne hrane. Na ovaj način se obezbeđuju funkcionalni proizvodi koji sadrže dovoljnu količinu visokovrednih jedinjenja koja imaju veću bioraspoloživost i finalan zdravstveni efekat. Zbog niza prednosti inkapsulirane forme ekstrakta imaju veliki potencijal primene u industriji u vidu boja i aditiva, tj. funkcionalnih dodatakau prehrembenim ali i kozmetičkim proizvodima. Istraživanja u okviru disertacije omogućavaju dobijanje inovativnih proizvoda koji pro&scaron;iruju asortiman nutritivno vrednih proizvoda i doprinose kvalitetnijoj ishrani potro&scaron;ača.<br />Upotrebom nusproizvoda prerade voća i povrća smanjuje se količina otpada i doprinosi za&scaron;titi životne sredine, povećava dobit proizvođača kroz pobolj&scaron;anje iskori&scaron;ćenja sirovine i konkurentnosti na trži&scaron;tu.</p> / <p>Within the thesis a new, nutrient-rich, fine bakery products based on flour of cereals and pseudocereals were created, through the production of which valorizing by-products of the food industry are produced- pomace beetroot. Results of the research provide new knowledge about degree of reduction bioactive compounds (polyphenols and betalains) during process of production and storage of fine bakery products enriched with beetroot pomace extracts, as well as their influence on non-enzymatic tanning reactions.<br />Successfully realized researches have indicated degree of stability bioactive compounds from beetroot pomace by encapsulation on soy protein and justification of application this method (technique) in the production of functional food. In this way, functional products witch contain a sufficient amount of high-value compounds which have higher bioavailability and final health effect are provided. Due to a number of advantages, encapsulated form of the extract have a great potential for application in industry like food color and additives, ie. functional supplements for food and cosmetic products. Research in the framework of the thesis allow obtaining innovative products which expand the range of nutritionally valuable products and contribute to the quality consumers diet.<br />Using by-products of processing fruits and vegetables reduces the amount of waste and contributes to the protection of environment, increases the profit of producers by improving the efficiency of raw materials and market competitiveness.</p>
30

Les composés phénoliques des raisins : étude du potentiel qualitatif et des procédés émergeants d'extraction / The phenolic compounds of grapes : study of qualitative potential and emerging processes of extraction

El Darra, Nada 21 January 2013 (has links)
Ce travail porte sur l’amélioration de l’extraction des composés phénoliques à partir des raisins tout au long de la chaîne de la vinification en rouge. La qualité des vins rouges est en grande partie déterminée par les composés phénoliques. Parmi les composés phénoliques, les anthocyanes, qui sont responsables de la couleur, et les tanins, à l’origine de la sensation d’astringence. Pour augmenter la quantité des composés phénoliques présents dans le vin, un développement des procédés permettant d’améliorer la diffusion des composés phénoliques durant la vinification en rouge doit être mis en jeu. Nous avons entamé notre étude par un suivi de la maturité phénolique des raisins rouges appartenant à différentes parcelles de la société château KSARA localisées dans la vallée de la Békaa tout en se servant des méthodes Glories (1&2) et ITV. Quant à l’amélioration de l’extractibilité des composés phénoliques durant la vinification en rouge, différents prétraitements ont été appliqués dans le but d’améliorer la diffusion de ces composés. Parmi ces procédés, les technologies suivantes ont été abordées dans notre étude: les électrotechnologies (CEP), les ultrasons, le chauffage modéré, le traitement enzymatique, la macération préfermentaire à froid et la thermovinification. Ces techniques permettent d’endommager ou de fragiliser les membranes et/ou parois cellulaires facilitant ainsi la libération du contenu cellulaire vers le milieu extérieur. Les cinétiques d’extraction des composés phénoliques ont pu être modélisées par le modèle empirique de Peleg et le modèle cinétique simplifié afin d’estimer les rendements d’extraction. De plus, dans ce travail, l’accent a été mis sur les propriétés antiradicalaires et antimicrobiennes des composés phénoliques extraits de différentes variétés de raisins fournis par la société Château KSARA. Pour valoriser les co-produits de la vinification, le chauffage ohmique pulsé (COP) a été appliqué sur le marc du raisin dans le but d’améliorer l’extraction de ses composés phénoliques. L'optimisation du choix de la date des vendanges et l'amélioration des procédés d’extractions des composés phénoliques durant la vinification en rouge, pourraient nous conduire à élaborer un vin d'une meilleure qualité. Ce travail étant effectué, il sera intéressant comme projet à venir de valider ces différents pré-traitements à grande échelle pour une perspective d’application industrielle. / This study focuses on improving the extraction of phenolic compounds from grapes throughout the chain of red winemaking. The quality of wine is mainly determined by the phenolic compounds. From these phenolic compounds, the anthocyanins, which are responsible of the color and tannins, the responsible of the astringency. In order to increase the amount of phenolic compounds present in wine, a development of methods used to improve the extraction of phenolic compounds during the red vinification should be discussed. We began our study by using two methods Glories (1&2) and ITV to monitor the phenolic maturity of red grapes grown in the vineyards in the province of Bekaa-Château KSARA S.A.L. Whereas for the improvement of the extractibility of phenolic compounds during the vinification, different pre-treatments were applied in order to ameliorate the diffusion of these compounds. Among these process, the following technologies were discussed in our study: the electrotechnologies (PEF), the ultrasound, the moderate heat treatment, the enzymatic treatment, the cold maceration and the thermovinification. These techniques are able to weaken the cell walls and facilitate the diffusion of grape’s phenolic compounds during vinification. Peleg’s equation and the simplified kinetic model were shown to be suitable for describing the extraction kinetics for phenolic compounds and for the estimation of the extraction yield of polyphenols. Furthermore, in this study, the antiradical and antimicrobial activities of phenolic compounds extracted from grapevine varieties of Château KSARA-Bekaa-Lebanon were analyzed. To valorize the by-products of the vinification, the pulsed ohmic heating (POH) was applied on the grape pomace in order to ameliorate the extraction of the phenolic compounds. The optimization of the choice of the harvesting date and the amelioration of the extraction of phenolic compounds during the red vinification, will conduce to elaborate a high quality of wine. After this study, it will be interesting to validate the different pre-treatments at large scale for a perspective of an industrial application.

Page generated in 0.4237 seconds