Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xiv, 169 p.; also includes graphics (some col). Includes abstract and vita. Advisor: David E. Hahn, Dept. of Agricultural, Environmental & Development Economics. Includes bibliographical references (p. 164-169).

Taken as an engineering material, mozzarella cheese can be considered as a complex food system that has dynamic structure and complex flowproperties. Food scientists have been actively developing methods to characterize mozzarella cheese rheologically, but most of these methods are empirical in nature. In the past decades, there has been a paradigm shift towards the utilization of well-developed rheological methods which have been widely applied in the study of commercial synthetic polymers. In this work, the rheology of mozzarella cheese was studied using well-developed rheological techniques. Utilizing various rheometers, the linear and non-linear rheology of mozzarella cheese was examined. General practical properties of mozzarella cheese such as meltability, flowability and stretchability were extracted from these results. Capillary flow and rolling experiments were also performed to determine their suitability as innovative post-production processing techniques for mozzarella cheese. Finally, a comparative study on the effect of frozen storage on the rheology of three different brands of mozzarella cheese was performed. In general, it was found that mozzarella cheese can be classified as a pseudoplastic (shear thinning) semi-solid material possessing a yield stress at room temperature. Upon heating, the yield stress gradually diminishes and it can be considered as a viscoelastic fluid. The results obtained from the various rheometers indicate that the yield stress, duration of experiment, sample geometry and temperature greatly affect the consistency of the results. It was also shown that extrusion can be used as a processing technique for mozzarella cheese above a certain temperature where the cheese is in a melt state. Rolling was also found to be a potentially feasible processing method. Finally, in terms of the effect of frozen storage, in general, the dynamic moduli decrease with the period of storage due to the freezing of the proteins in the cheese.

No description available.

A sensory method was developed to determine cheese texture by hand evaluation. Cheese sensory evaluation was conducted by panelists (n=8) on four commercial samples in duplicates. Standards, descriptors, methods of each attribute evaluation, sample size, and ballot were developed based on panelists' consensus. Fifteen total attributes, divided into five groups, were tested. Crumbliness was defined as the ease of the sample to break apart during manipulation using the thumb and two fingers for five times. Using Principal Component Analysis (PCA), four components were extracted with the first two explaining most of the variability (60.4%). PCA showed that moistness, crumbliness, color, cohesiveness, irregularity, and oiliness were the main attributes describing the samples. Irregularity and cohesiveness had 83.6% and -88.1% correlations with crumbliness, respectively. Panelists' performances were not significantly different (p≤0.05) and each subject used the method consistently for crumbliness. This method was then applied to evaluate and compare the sensory attributes of Queso Fresco. Three types of Queso Fresco cheese were made: raw cheese (RC), High Hydrostatic Pressure (HHP) treated raw cheese (HP), and cheese made from HHP treated milk (HPM). Sensory attributes, compositions, microstructures and protein profile were compared. Sensory attributes were examined by ten trained panelists using hand evaluation method developed and instrumental methods (Texture Profile Analysis (TPA) and 80% compression test). Protein, fat, and moisture contents were valuated by Micro Kjeldahl, Babcock, and Forced air draft oven respectively. Microstructure was examined by light microscopy using Acid Fuschin protein staining, while native and SDS PAGE were carried out to show the protein profile. One and eight days storage times were studied. HHP treatment of cheese or cheese milk (400 MPa, 20 min, ambient temperature) were shown to reduce microbial loads. HP and RC had similar microstructure, compositional (p-value≤0.05), and sensory attributes, except color (p-value≤0.05). HP and RC had distinct protein network, while HPM had a very diffuse network. HPM was different from both RC and HP. HPM was the least firm, least crumbly, most sticky and oily. HPM day one was firmer, less oily, less springy than day eight. HPM had higher moisture and yield, due to incorporation of denatured whey proteins, than RC and HP cheese. The hand evaluation method developed was proven to be able to differentiate cheese textural attributes. Overall, HHP treatment of Queso Fresco produced cheese with similar characteristics as traditionally made Queso Fresco, while HHP treatment of cheese milk created cheese with weak texture characteristics. HHP treatment of cheese might be an alternative way to produce Queso Fresco with acceptable attributes and reduced microbial load. / Graduation date: 2003

Graduation date: 1961

Taken as an engineering material, mozzarella cheese can be considered as a complex food system that has dynamic structure and complex flowproperties. Food scientists have been actively developing methods to characterize mozzarella cheese rheologically, but most of these methods are empirical in nature. In the past decades, there has been a paradigm shift towards the utilization of well-developed rheological methods which have been widely applied in the study of commercial synthetic polymers. In this work, the rheology of mozzarella cheese was studied using well-developed rheological techniques. Utilizing various rheometers, the linear and non-linear rheology of mozzarella cheese was examined. General practical properties of mozzarella cheese such as meltability, flowability and stretchability were extracted from these results. Capillary flow and rolling experiments were also performed to determine their suitability as innovative post-production processing techniques for mozzarella cheese. Finally, a comparative study on the effect of frozen storage on the rheology of three different brands of mozzarella cheese was performed. In general, it was found that mozzarella cheese can be classified as a pseudoplastic (shear thinning) semi-solid material possessing a yield stress at room temperature. Upon heating, the yield stress gradually diminishes and it can be considered as a viscoelastic fluid. The results obtained from the various rheometers indicate that the yield stress, duration of experiment, sample geometry and temperature greatly affect the consistency of the results. It was also shown that extrusion can be used as a processing technique for mozzarella cheese above a certain temperature where the cheese is in a melt state. Rolling was also found to be a potentially feasible processing method. Finally, in terms of the effect of frozen storage, in general, the dynamic moduli decrease with the period of storage due to the freezing of the proteins in the cheese.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xix, 181 p.; also includes graphics (some col.). Includes bibliographical references (p. 158-168). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 234-244).

Thesis (M.S.)--University of Wisconsin--Madison, 1980. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 49-55).