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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.
251

Podnikatelský záměr - založení výrobního podniku / Business Plan - Founding of a Manufacturing Company

Houšťava, Jiří January 2017 (has links)
The subject of this diploma thesis is the business plan for the establishment of a manufacturing company. The company will operate mainly in the food industry. Thesis is divided into three parts, namely theoretical, analytical and practical. The theoretical part describes the theoretical data related to the preparation of the business plan, the analytical part is dedicated to analysis of the state and practical part contains own suggestions in several variants.
252

Fabrication of zein-based biodegradable surface enhanced Raman spectroscopy biosensor platforms for the detection of food toxins

Hazal Turasan (9028997) 26 June 2020 (has links)
Identifying and detecting health hazards in food products, especially contaminants and toxic substances such as allergens, food toxins and agricultural residues from pesticides, remains a challenge. Increasing demand for food products and growing health consciousness necessitate rapid and accurate measurements which can be easily conducted on-site without long measurement times and high costs. Due to their ease of use, accuracy sample preparation and rapidity, biosensors have started to outcompete time-consuming lab-scale analytical devices. However, as the use of biosensors increase, a concern of the amount of plastics and synthetic polymers used in the fabrication of these biosensors rises. In this dissertation, new ways to create biodegradable and eco-friendly plant-based SERS biosensor platforms from corn protein, zein, are presented. Its higher hydrophobicity and film forming capability make zein a very suitable biopolymer for fabricating biosensors. In the first part of this dissertation, chemical crosslinking was tested to improve the surface hydrophobicity, surface roughness (using AFM), mechanical properties, kinetics of gelation and film formation of zein films, and as a result zein-film based SERS platforms with fewer defects could be fabricated. In the second part, the detection sensitivity of the zein film-based SERS platforms was increased with metallic nanoparticle decoration (gold, silver or silver-shelled-gold). The addition of all three types of nanoparticles significantly increased the SERS enhancement factors of the platforms, with silver-shelled-gold nanoparticles giving the highest enhancement factor of 10<sup>5</sup>. In the last part of this thesis, a novel approach was tested, where electrospun zein nanofibers decorated with metallic nanoparticles were used as a SERS biosensor platform. Due to their higher surface area-to-volume ratios, electrospun zein nanofibers gave a higher SERS enhancement factor (10<sup>6</sup>). This enhancement factor enabled the detection of acrylamide, a food carcinogen, with a 10<sup>4</sup> times lower detection limit than nanophotonic based nanoimprinted zein, acrylamide sensor platform. Overall, this dissertation successfully shows the fabrication of biodegradable and eco-friendly SERS sensor platforms that have comparable detection sensitivities to those of non-biodegradable ones.
253

Development of a Non-Intrusive Continuous Sensor for Early Detection of Fouling in Commercial Manufacturing Systems

Fernando Jose Cantarero Rivera (9183332) 31 July 2020 (has links)
<p>Fouling is a critical issue in commercial food manufacturing. Fouling can cause biofilm formation and pose a threat to the safety of food products. Early detection of fouling can lead to informed decision making about the product’s safety and quality, and effective system cleaning to avoid biofilm formation. In this study, a Non-Intrusive Continuous Sensor (NICS) was designed to estimate the thermal conductivity of the product as they flow through the system at high temperatures as an indicator of fouling. Thermal properties of food products are important for product and process design and to ensure food safety. Online monitoring of thermal properties during production and development stages at higher processing temperatures, ~140°C like current aseptic processes, is not possible due to limitations in sensing technology and safety concerns due to high temperature and pressure conditions. Such an in-line and noninvasive sensor can provide information about fouling layer formation, food safety issues, and quality degradation of the products. A computational fluid dynamics model was developed to simulate the flow within the sensor and provide predicted data output. Glycerol, water, 4% potato starch solution, reconstituted non-fat dry milk (NFDM), and heavy whipping cream (HWC) were selected as products with the latter two for fouling layer thickness studies. The product and fouling layer thermal conductivities were estimated at high temperatures (~140°C). Scaled sensitivity coefficients and optimal experimental design were taken into consideration to improve the accuracy of parameter estimates. Glycerol, water, 4% potato starch, NFDM, and HWC were estimated to have thermal conductivities of 0.292 ± 0.006, 0.638 ± 0.013, 0.487 ± 0.009, 0.598 ± 0.010, and 0.359 ± 0.008 W/(m·K), respectively. The thermal conductivity of the fouling layer decreased as the processing time increased. At the end of one hour process time, thermal conductivity achieved an average minimum of 0.365 ± 0.079 W/(m·K) and 0.097 ± 0.037 W/(m·K) for NFDM and HWC fouling, respectively. The sensor’s novelty lies in the short duration of the experiments, the non-intrusive aspect of its measurements, and its implementation for commercial manufacturing.</p>
254

Evaluation of Small-Scale Extrusion for Aflatoxin Decontamination of Maize in Kenya

Margaret Leah Hegwood (9159503) 24 July 2020 (has links)
<p>Aflatoxins, secondary metabolites produced by the molds <i>Aspergilllus flavus</i> and<i> A. parasiticus</i>, are estimated to affect upwards of 25% of the world’s global food supply. For Low and Middle-Income Countries like Kenya, a combination of trade, economic, and health challenges related to aflatoxin contamination present a serious threat to food and national security. One option for reducing aflatoxin risks in countries like Kenya is deploying small-scale, reprocessing technologies that degrade aflatoxin in contaminated food products. One potential technology for reprocessing is small-scale extrusion (60 pph) like the TechnoChem Mini-Extruder™.</p><p> First, to understand the extent of aflatoxin contamination in Kenyan maize, two field work trials were conducted in Uasin Gishu County, Kenya. Aflatoxin levels from each sample were analyzed and compared to a variety of agro-economic variables (e.g. farm size) using a stepwise multiple linear regression. Upon analysis, only 5% of maize samples collected during field work tested positive for unsafe levels of aflatoxin ( >10 ppb). Thus, the resulting regression model is highly biased towards predicting low aflatoxin levels. Such bias makes any inferences to predict high aflatoxin levels in maize largely inconclusive. The inherent heterogeneity of aflatoxin and the history of wide-spread contamination in Kenya further supports the conclusion that more studies are needed to understand the true extent of aflatoxin contamination in Uasin Gishu maize.</p><p> Second, to test the effectiveness of small-scale extrusion on aflatoxin degradation in maize, contaminated samples were processed at varying motor frequencies (15, 38, and 50 hz) and moisture contents (35, 40, 45 %wb). Moisture content is significant (p-value < 0.05) in aflatoxin degradation. Total aflatoxin degradation varied between 11 and 83% depending on processing conditions. Maximum degradation occurred at 40 %wb product moisture with a residence time of 265.1 s and an effective shear rate of 56.5 1/s. Thermal degradation is considered negligible due to low temperature increases. Consequently, all degradation is attributed to shear forces inside the extruder. Shear rates were approximated using the Harper model with moisture content and residence time being the most significant factors affecting shear effects on aflatoxin degradation. Although significant aflatoxin degradation occurred in the extruder, further studies are necessary to understand the role of processing parameters on aflatoxin degradation before small-scale extrusion can be confirmed as a viable reprocessing technology.</p>
255

The Recovery of Protein from Egg Yolk Protein Extraction Granule Byproduct

Kaufman, Irene Jennifer 01 June 2017 (has links)
In addition to proving an excellent source of nutrients, eggs are used in the food, cosmetic, and biotechnology industries for their rheological and bioactive properties. Much of the potential for the added value is in individual components of the egg, rather than the whole egg. At low speed centrifugation, yolk separates into two distinct fractions—granules and plasma. It is becoming increasingly popular in the industry to remove the plasma fraction of the egg yolk to use for its livetins, particularly immunoglobulin Y, leaving behind a granule by-product (“yellow cake”). Previous research has shown potential added-value from the granule fraction, especially from its phosvitin and phospholipids. Granules are protein aggregates with complexes of phosvitin and high density lipoproteins linked by phosphocalcic bridges. In their native form, the proteins are mostly insoluble, however previous studies have shown the links can be broken by alterations in pH, ionic strength, and mechanical treatments. This thesis project seeks to find potential uses for the egg yolk by product after the removal of the livetin fraction by means of further fractionation with mechanical treatment (filtration). Two variables were tested to extract more proteins from the yellow cake. Salt was added to 10% solids solution of yellow cake in water before filtration at four different NaCl levels: 0%, .05%, 1%, and 2.5%. Additionally pH was tested at four different levels: 4.6, 4.8, 5.0, 5.2. The samples were also tested for antibacterial properties against Escherichia v coli with a minimum inhibitory concentration assay (MIC). Analysis with BCA showed salt concentration had a significant effect on the yield of protein. The highest concentration of salt tested, 2.5%, had the highest protein yield. Additionally, SDS PAGE showed 2.5% salt had the most unique protein bands. This could be to the disruption of the phosphocalcic links between the phosvitin and HDL by NaCl, allowing the protein to solubilize. pH did not have a significant effect on the yield or types of proteins in the range tested in this experiment. There is no conclusive evidence of antibacterial properties against E. coli from the protein extract. The MIC assay had growth show up in all wells with the protein extract, however there was a visible decrease in turbidity with higher concentration of the protein extract. This could mean that the protein extract does have some antibacterial properties, but needs testing at higher concentrations or with isolated proteins/peptides. The SDS-PAGE revealed bands showing phosvitin present, which has known antibacterial properties. Overall, improvements to the methods for further protein extraction from egg yolk by-products will help lead the industry to finding novel uses and product applications.
256

INTERACTIONS AMONG PROTEINS AND CARBOHYDRATES UNDER THERMAL PROCESSING CONDITIONS AND THEIR EFFECTS ON DAIRY FOULING

Yizhe Zhang (8986394) 23 June 2020 (has links)
<p>In dairy processing, dairy ingredients need to be thermally treated to ensure product quality and safety for an extended shelf life. During thermal processes, milk protein denatures and interacts with other dairy ingredients to form a layer of deposit on heated surfaces, known as fouling which can deteriorate process efficiency and product safety. Milk is a complex mixture of proteins, fats, carbohydrates, minerals and vitamins. The heat-sensitive B-lactoglobulin (B-lg) is known to be a key component in fouling formation (constituting 50% of type A fouling deposits) during milk pasteurization, as B-lg unfolds when heated and exposes the reactive sulfhydryl groups that can interact with other proteins and ingredients to form deposits. Although casein (80% of milk proteins) is known to interact with denatured B-lg, no fouling studies have been performed with particular focus on the effect of casein on whey protein fouling.</p><p>Carbohydrates are an ingredient widely added in various dairy products as sweetener, stabilizer, texturizer, and fat replacer. Simple sugars have a protective effect on whey protein denaturation, but their effect on dairy fouling is not known. Polysaccharides can interact with milk proteins through electrostatic and hydrophobic interactions, as well as hydrogen bonding. The addition of polysaccharide (carrageenan) has been reported to cause opposite effects on protein deposition, however, no conclusive mechanism has been proposed to elucidate how protein-polysaccharide interaction at pasteurization temperatures affects the fouling behavior of dairy products.</p><p>In this dissertation, different model dairy solutions and real dairy products were used to study the effect of composition, including protein distribution and additions of simple sugars and polysaccharides, on dairy fouling. Fouling deposits were formed and analyzed using a bench-top spinning disc apparatus operating under well-controlled temperatures and shear stresses characterized by computational fluid dynamics simulations. By studying the fouling behavior of camel milk and comparing with bovine milk, milk without B-lg was found to still foul and form deposits containing casein, α-lactalbumin, serum albumin with a reduced thermal resistance due to a more porous structure. Results also showed that the addition of 10 wt% sugar reduced whey protein fouling by more than 30% and affected the structure and adhesion strength of deposits. Furthermore, the presence of carrageenan in dairy solutions can promote the denaturation of B-lg when heated and form a more compact deposit, resulting in more severe fouling. Overall, this dissertation provides a fundamental understanding of the fouling characteristics of complex dairy products. The knowledge gained is expected to help the dairy industry select suitable ingredients to mitigate or prevent the fouling problem.</p>
257

Examination of Strategic Management Accounting Techniques among SMEs (Perception of the Usefulness, Adoption, and Outcomes) : A multiple Case Study of SMEs in the Food Processing Industry in Nigeria

Akhtar, Muhammad Naveed, Eniodunmo, Kayode Olumide January 2021 (has links)
Purpose: This thesis examines the perception of the usefulness of SMAT, its adoption, and expected outcomes among SMEs in the food processing industry of Nigeria. Research Questions: Three research questions have been addressed in this thesis; (1)What is the perception of the usefulness of SMAT among SMEs in the food processing industry in Nigeria? (2) What leads to SMEs adoption of SMAT (antecedents) among SMEs in the food processing industry in Nigeria? and (3) What outcomes (consequences) are believed to result from using SMAT among SMEs in the food processing industry in Nigeria?  Methodology: Qualitative studies are employed to handle empirical data gathering by semi structural interviews from four SMEs in the food processing industry in Nigeria. The data has been analyzed and thoroughly discussed in the light of previous theories, and findings are presented. Findings: A significant positive perception of the usefulness of SMAT among the selected SMEs in the food processing industry in Nigeria was observed. With few exceptions, costing techniques, customer-focused techniques, and competitors' accounting are moderately and highly perceived while customer accounting techniques are not in use. The most adopted technique is target costing, and the other including; pricing strategy, competitor position tracking, brand valuation, and life cycle costing. Moreover, the management of the sample SMEs thought that benchmarking is the most suitable method to meet their operational targets. The perception of usage of SMAT positively and significantly impacts the perception of increasing customer base and obtaining competitive advantage. The findings imply that SMAT could replace the traditional management accounting practices such as budget and budgetary control in SMEs. Further, human capital is a more influential factor for SMEs than technology because human capital is better positioned to decide which technological tools are more effective for the firms to implement them in their business processes and operations to achieve the organizational goals. Significance of the Study: The research work contributes towards the literature by increasing the knowledge regarding the perception of the usefulness of SMAT and the implications of SMAT practices and its awareness in the SME sector. The larger and smaller firms' policymakers, owners, and managers can benefit through the knowledge and awareness of SMAT and its implementation in their day-to-day business operations. Moreover, the knowledge of using SMAT can enhance the effectiveness of the organizations in achieving their goals that would result in the overall prosperity of the economy of any country. Limitations: The study is restricted to the perception of the usefulness of SMAT, level of adoption, and outcomes among SMEs operating in the food processing industry with a sample size consist of four companies and limited to participants’ in particular geographic regions of Nigeria; therefore, provided information may not be valid for other areas and markets. This fact limits the global generalizability of our findings.
258

Enzymic Milk Coagulation: Casein Micelle Aggregation and Curd Formation

McMahon, Donald J. 01 May 1983 (has links)
Enzymic milk coagulation was monitored by measuring changes in curd firmness and apparent absorbance of undiluted milk. Detection of coagulation, visually or rheologically, occurred after the milk changes from a system of aggregating particles to an extended space network. This change was observed as a shoulder in apparent absorbance plots and coagulation time was defined as the critical point in the aggregation process analogously to non-linear condensation polymerization reactions. It corresponds to the inflexion point during the period when apparent absorbance was rapidly increasing and can be calculated by fitting curd firmness data to an exponential equation. Addition of calcium chloride to milk reduced coagulation time with a minimum occurring at .05M calcium. Also, curd firmness increased with a maximum at .02M calcium. It appears that calcium affects all stages of coagulation: proteolysis, micelle aggregation, and gelation. When bulk culture media was added to milk, the pH of the media had a greater effect on coagulation time than did presence of phosphate in the media. Non-specific proteolytic activity of milk coagulants affects the initial rate of curd firming but not the maximum firmness. The more proteolytic the enzyme the slower the curd firming rate. This can be used to rapidly assay for pepsin content of bovine rennets.
259

A Study of Factors Controlling Physical Properties of Mozzarella Cheese and the Manufacture of a Reduced Fat Mozzarella Cheese

Merrill, Richard Kevin 01 May 1993 (has links)
Variables affecting the physical properties of Mozzarella cheese were investigated. The effects of various milk-clotting enzymes were examined. The type of milk coagulating enzyme used played a significant role in determining physical properties of direct acid Mozzarella cheese. Cook color was not affected by enzyme type, but melt and stretch were significantly affected. Proteolytic nature of starter cultures was reviewed and recommendation s were give n. Cheese made with proteinase-deficient strains had more stretch after holding for 14 and 28 d than cheese made with non-deficient strains. Cheese made with pairs or single strains of L. helveticus had the same melt, more stretch, and less cook color than cheeses made with paired strains of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. Frozen storage, thawing, and shredding of Mozzarella cheese were described and suggestions given for optimizing shelf life. Shredding, freeze temperature, thaw temperature , and time of storage had no effect on cook color. Frozen, shredded cheese stretched more and melted less than non-shredded frozen cheese. Reduced fat, high moisture Mozzarella cheese was made and found acceptable when compared to low moisture part-skim Mozzarella cheese. Reduced fat cheeses decreased in stretch and increased in melt throughout storage. Differences in stretch, melt, and cook color were not significant from one casein-to-fat ratio to another. Reduced fat, high moisture Mozzarella cheese was made with partial or total replacement of L. helveticus with L. casei ssp. casei and was found to compare well with low moisture part-skim Mozzarella cheese. Cheese made with L. casei ssp. casei cultures, paired with either S. salivarius ssp. thermophilus and L. helveticus or just S. salivarius ssp. thermophilus, had the least stretch and the greatest melt.
260

The Influence of Hot Brine on the Calcium Content, Score, and Physical Properties of Low-Fat, Cheddar-Like Cheese

Ogden, Robert V. 01 May 1967 (has links)
Two factors that are important in the production of the typical body and texture of cheddar cheese are acid development and milk fat content. When either of these is absent or present in less-than-normal amounts, the resulting cheese shows marked defects of curdiness and firmness.

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