Date of Award:

8-2024

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Committee Chair(s)

Silvana Martini

Committee

Silvana Martini

Committee

Luis Bastarrachea

Committee

Robert E. Ward

Committee

Prateek Sharma

Committee

David Britt

Abstract

Fats play a significant role in shaping the characteristics of foods, influencing texture, mouthfeel, appearance, and nutritional attributes. An important property of fats is their ability to entrap liquid oil known as oil binding capacity (OBC). Poor OBC of fats frequently leads to shortened-shelf life of foods caused by quality issues due to unwanted chemical and physical changes. In natural nut butters without additives, low OBC often results in a visual oil layer forming at the surface. In filled chocolates such as truffles, pralines, and peanut butter cups this low OBC can result in unwanted textural and visual changes.

The OBC of fats is determined by the physical and chemical characteristics. In this dissertation, the relationship between the physical properties and OBCs of fats is examined. To better understand the relationship between the physical properties and OBC of fats, a wide range of physical properties are generated by using different processing conditions, storage temperatures, and diluting the fats with liquid soybean oil (SBO). Additionally, the impact of chemical characteristics on the OBC of fats is studied by examining three types of fats – a soybean-based fat, a palm-based fat, and a palm-kernel-based fat that have different chemical compositions.

The fats studied in this project were solidified quickly or slowly as well as with or without a processing tool – high-intensity ultrasound (HIU), which has been shown to modify the structure of fats. The physical properties of the solidified fats were measured including the texture, amount of solid fat, the temperature that the fats melted at, the amount of energy required to melt the fats, and the size of the solid particles. After the initial solidification of the samples, they were stored at room and refrigeration temperatures and the same physical properties were measured once more. The OBC of the fats was calculated using two methods. In the first method, the samples were spun in a centrifuge and the liquid oil that moved to the top was removed. In the second method, the fats were placed on top of a paper allowing the liquid oil to move onto the paper which was weighed.

The relationship between the physical properties and OBC for both methods was evaluated, and it was found that fats with high amounts of solid fat, hard textures, and higher amounts of energy required to melt the fat were related to higher OBC. Additionally, fats stored at refrigeration temperatures, that contained less liquid oil, and were crystallized quickly with HIU tended to retain more liquid oil. Overall, this work indicates that the OBC of fats can be improved by changing the physical properties.

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