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Effect of protein source and homogenization pressure on storage stability of retort processed dilute whey protein emulsions
Abstract
Emulsions stabilized with acid whey or sweet whey were prepared using homogenization pressures of 30 or 90MPa. The emulsions were then canned and sterilized at 250F for 5 minutes. Emulsion stability, particle size and rheological properties were measured before and after sterilization. Glycomacropeptide (GMP) was added to an acid whey emulsion to equal the concentration of GMP in sweet whey and emulsion properties measured before sterilization. Sterilized emulsions were analyzed after 1,7,15 or 30 days of storage at room temperature. The stability of non-sterilized sweet whey and acid whey emulsions homogenized at 30 or 90MPa was not different. However, a significant increase in the stability of emulsions was observed when homogenization pressure was increased from 30 to 90MPa. Addition of GMP to emulsions prepared using acid whey increased emulsion stability compared to emulsions made with acid whey and sweet whey when the emulsions were homogenized at 30MPa but not at 90MPa. The viscosity of acid whey emulsions was increased significantly with the addition of GMP. However, when the homogenization pressure was increased from 30 to 90MPa there was a decrease in viscosity. Sweet whey emulsions homogenized at 30MPa were more stable than acid whey emulsions homogenized at 30MPa for 15 days of storage but not after 30 days of storage. There was no difference in emulsion stability of sterilized acid whey and sweet whey emulsions for the first 15 days but sweet whey emulsions were more stable after 30 days storage. Particle size (dvs) was indirectly related to emulsion stability. Acid whey emulsions were more viscous than sweet whey emulsions during storage. However, homogenization at 90MPa compared to homogenization at 30MPa decreased the viscosity of acid whey emulsions but increased viscosity of sweet whey emulsions. Gelation was not observed during storage. The composition of the fat globule membrane for the sweet whey emulsion was changed by homogenization pressure and sterilization with highest concentration of GMP in the fat globule membrane for non-sterilized emulsions homogenized at 30MPa. Sterilization and homogenization of the emulsion at 90MPa reduced GMP and increased b-lactoglobulin concentration in the fat globule membrane compared to the non-sterilized emulsion homogenized at 30MPa.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 75-79).
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Citation
Bhatia, Sachin (2001). Effect of protein source and homogenization pressure on storage stability of retort processed dilute whey protein emulsions. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2001 -THESIS -B494.
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