Identifier

etd-06282011-144209

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

Market and nutritional values of fermented milks can be enhanced by adding microencapsulated polyunsaturated fish oil and vitamin E. Polyunsaturated fatty acids (PUFAs) lower the risk of heart disease and vitamin E is an important lipophilic antioxidant that protects cell membranes from oxidation. This study aimed to develop functional yogurts YMSO and YMMO fortified with á-tocopherol and microencapsulated salmon oil (MSO) or microencapsulated menhaden oil (MMO), respectively and to evaluate their physicochemical properties during 1-mo of storage. Stable emulsions were prepared with 7% red salmon oil (SO) or menhaden oil (MO), 22% arabic gum, 11% maltodextrin, 0.83% á-tocopherol and 59.17% water. The emulsions were spray dried and MSO or MMO were produced. Plain yogurt (PY) was produced and 2% of MSO or MMO were added to three batches of yogurt to produce YMSO or YMMO. PY and yogurt with 22% arabic gum and 11% maltodextrin (YPAM) were used as controls. Yogurts were analyzed for syneresis, pH, color, lactic acid bacteria (LAB), thiobarbituric acid (TBA) value, fatty acid methyl esters composition, á-tocopherol content, rheological properties and microstructure. Triplicate experiments were conducted and data was analyzed at á=0.05. After 1-mo storage, the yogurts pH decreased and syneresis slightly increased regardless of the treatment and all yogurts had a similar reduction in LAB counts from 8 Log CFU/g to 6 Log CFU/g. á-Tocopherol contents of YMMO and YMSO were significantly (P<0.05) higher than those of PY and YPAM during the 4 week storage study. Initial PY, YPAM, YMMO and YMSO á-tocopherol contents were 37.65 ± 3.17, 43.03 ± 0.71, 75.61 ± 0.98, and 72.09 ± 0.18 µg/g yogurt, respectively. All yogurts had low TBA values and YMMO and YMSO had significantly higher (P<0.05) total ù-3 content than the controls. All yogurts were described as pseudoplastic fluids and showed viscoelastic characteristics during 1 month storage. The study demonstrated that PY can be fortified with fish oil and á-tocopherol.

Date

2011

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Sathivel, Subramaniam

DOI

10.31390/gradschool_theses.2900

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