Author

Haoyuan Zohng

Date of Award:

5-2013

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Advisor/Chair:

Dr. Silvana Martini

Abstract

The effect of commercial shortenings (butter, lard, margarine, all-purpose shortenings, soybean oil, and interesterified soybean oil) on the physical and sensory characteristics of baked products was evaluated. Results showed that lipid viscoelastic character, melting point, onset melting temperature (Ton), and melting enthalpy (ΔH) affect the physical qualities of baked products, such as batter density of cake, spread of cookies, and breaking strength of pie crust. With a larger value (less plastic character), less crystal structure is present in the lipid and fewer air bubbles were incorporated into cake batter, which results in a denser batter. With a liquid character, lipid prevents water-flour interaction by coating flour particles, which develops less gluten in pie crust, indicated by its low breaking strength. The ΔH can be extrapolated to the amount of crystalline material in the lipid: the larger ΔH, the more crystalline material. In cookie production, a low ΔH make the lubricant effect of a lipid available larger cookie spread than the one observed in cookies made with a shortening with high ΔH values. The effect of ultrasound (US)-treated interesterified soybean oil (IES) on the quality characteristics of baked goods was also evaluated. US-treated and non US-treated IES were prepared at 32°C and tempered for 48 h at 5 and 25°C. US-treated IES had smaller lipid crystals than non US-treated IES. In cakes, the highest cake batter density was obtained when non US-treated IES tempered at 5°C was used. This was a consequence of the larger lipid crystals obtained under this condition, which had less ability to incorporate air. In cookies, the fewer crystals (more fluid status) present in non US-treated IES tempered at 25°C led to a higher dough density, higher spread, and lower height in the final cookies. Similarly, in pie crust, the larger amount of lipid crystals in US-treated IES contributed to significantly higher height in final pie crust.

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