Date of Award

12-2015

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Mary Ellen Camire

Second Committee Member

Jason Bolton

Third Committee Member

Douglas W. Bousfield

Abstract

Ice cream generates $8.4 billion in annual revenue in the United States. Almost half a billion gallons of low-fat or nonfat ice cream were produced in 2014, and these values are only expected to increase. Changes in consumer eating behaviors have forced the ice cream industry to offer low-fat and non-fat options. These changes in habits are inspired by the need to combat health issues such as obesity, diabetes, and other metabolic disorders. The enrichment of foods to increase their nutritional value is extremely attractive to consumers, especially the addition of fiber to ice cream. Research has also suggested the enrichment of 'non-healthy foods' is more justified to the consumer that the fortification of 'healthy.'

The use of cellulose nanofibrils (CNF) as a food ingredient is not a new concept and has been around since its discovery in the 1980's. However, the high energy requirements of the CNF fibrillation process stymied commercial manufacture. Recently, lower energy costs and process improvements have made CNF production more affordable. Currently, CNF research focuses on the production of food packaging to replace plastics, with little research conducted about its usefulness as a food ingredient. Therefore, the goal of this study was to test the feasibility of CNF as a fat replacer in ice cream. However, the resulting products may not meet the U.S. Standard of Identity for ice cream. However, the term "ice cream" will be used to reference the products.

Four CNF ice cream formulations were developed, along with a full-fat control, over the period of several months following intensive research and trial and error. Three replicate batches of each formulation were produced. All ice cream formulations were subjected to a battery of analytical tests that included total solids content, overrun, color, meltdown, hardness, rheology, and fat content.

Overrun values for all formulations were all statistically similar, suggesting that the CNF did not affect the processing quality. There were no differences in whiteness between the CNF formulations and control samples. The ice cream was subjected to puncture testing to determine the hardness and adhesive qualities of the ice cream formulae. The addition of CNF to the ice cream formula increased the product's hardness. Formulas containing a higher CNF concentration produced harder ice cream. A material that is considered adhesive is associated with a high degree of mouthcoating that can be interpreted as the feeling of "richness." The "richness" of food is associated with its fat content. The higher the proportion of CNF, the more adhesive quality the formula exhibited. The addition of CNF reduced the melting of the ice cream product when compared to the control by up to 75%. Two methods of rheological analysis were conducted on the liquid ice cream formula. Steady shear rheology determines the effect shear had on the viscosity. Oscillatory rheology measures the viscoelastic behavior of the ice cream mix. Under steady shear, all ice cream mixes exhibited pseudoplastic behavior, which is typical for ice cream and CNF slurries. In oscillatory rheology, the ice cream mix continued to exhibit pseudoplastic behavior over the frequency range and exhibited solid-like behavior across the frequency range.

CNF appears to be an effective fat replacer within the structure of ice cream. Using this product we were able to produce an ice cream product that contained 1% fat, and had similar physical characteristics to "standard" ice creams. Future work should include scanning electron microscopy to identify how CNF altered the structure of ice cream as well as consumer acceptability testing.

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