Date of Award

Fall 12-15-2017

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Mary E. Camire

Second Committee Member

Mona Therrien

Third Committee Member

Kathryn Yerxa

Abstract

Advances in technology and medicine have extended the human lifespan. Not only the United States, but people all over the world are now living longer. Maine is one of the oldest states by median age. Maintaining optimum health contribute significantly to successful aging.

Many physical changes accompany the aging process. These changes affect taste and smell perception, thirst mechanism, swallowing capacity, and body composition. Such physical changes can lead to decrease appetite and food intake, thus increasing the risk of malnutrition and sarcopenia. Sarcopenia refers to the involuntary loss of skeletal muscle mass. In older adults, sarcopenia can be detrimental. Sarcopenia can be prevented with adequate nutrients and protein intake.

Protein intake and resistance exercise serve as stimulator to the mTOR pathway, which helps stimulate muscle protein synthesis. In older adults with anabolic resistance, increased protein intake and resistance exercise may be helpful in the battle against sarcopenia. Unfortunately, obtaining adequate intake from meals alone may not be feasible for many older individuals. Supplemental products such as Ensure® or Boost®, while containing a high amount of protein and calorie, may not be suitable for every older individual. The development of high protein, real food supplement, such as frozen yogurt, may provide an alternative option as supplements.

Three formulations of frozen yogurt, fortified with three types of protein, were developed. All frozen yogurt formulations were subjected to a series of physical properties test, including color analysis, viscosity, and overrun. A sensory analysis was also conducted to test the acceptability of the product. The objectives were to achieve 10 grams of protein and at least 100 kcals per 89 grams serving.

The L*, a* and b* values were significantly different by protein type, suggesting that protein powder affect the color of the final product. Casein formulations were the lightest and the least yellow and red. Air incorporation can lead to diluted color, and casein formulations had the highest overrun. There were differences in the L* and a* values between batches, which may be due to the use of ingredients from different containers. There was a significant difference in viscosity between protein types, batch and time intervals. The use of micellar casein resulted in the highest mean viscosity. Batch 1 had the significantly lower mean viscosity. Different aging time and over mixing may have contributed to the difference in viscosity between batches. The viscosity of mixes measured at 20 seconds was significantly different from viscosity measured at 5, 10 and 15 seconds. Frozen yogurt, similar to ice cream, exhibits thixotropy, which means that apparent viscosity decreased with time of applied stress. For overrun, there was a significant difference between protein types. Casein formulations had the highest overrun values. Sensory analysis was conducted at three local community cafés. A total of 21 individuals aged 60 and older participated. There was no significant difference in appearance, taste, texture, sweetness, ease of swallowing, and over acceptability between protein types, suggesting that protein types did not affect acceptability of frozen yogurt

Incorporation of protein powders into frozen yogurt increased its protein content. Due to the small number of participants in the sensory analysis, future research may need to extend to compare the effect of protein types on consumer acceptability. It would also be beneficial to analyze total nitrogen content, as well as performing more analytical tests such as hardness and melting rate. These tests may provide more evidence of fortified frozen yogurt being a healthy, palatability acceptable for older adults.

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