Master of Science / Department of Animal Sciences and Industry / Travis G. O'Quinn / The objectives of this study were to determine the effect of enhancement on consumer and trained beef palatability scores of three quality grades when cooked to three degrees of doneness (DOD) and to determine the accuracy and repeatability of the Pressed Juice Percentage (PJP). Striploins of USDA Prime, Low Choice, and Low Select quality grades were used in this study. To maximize variation in juiciness, steaks were either enhanced (formulated for 108% pump with a solution of water, salt, and alkaline phosphates) or non-enhanced, and cooked to three degree of doneness (Rare: 60°C, Medium: 71°C, or Very Well-Done: 82°C). All samples were evaluated for Warner-Bratzler shear force (WBSF), Slice Shear Force (SSF), PJP, and palatability traits by consumer and trained panelists. Consumer panelists rated all enhanced treatments similar (P > 0.05) to each other and greater (P < 0.05) for juiciness, tenderness, flavor liking, and overall liking than all non-enhanced treatments. Consumer ratings of juiciness, tenderness, and overall liking scores increased (P < 0.05) as DOD decreased. Consumer panelists rated all enhanced treatments similar (P > 0.05) and greater (P < 0.05) for the percentage of steaks classified as premium quality. For trained panel initial juiciness, all enhanced treatments and non-enhanced Prime samples were similar (P > 0.05) and greater (P < 0.05) than other treatments cooked to Medium and Very Well Done. Results indicated PJP had a relatively high repeatability coefficient (0.70), indicating that only 30% of the variation observed was due to sample measurement differences. The PJP threshold values evaluated accurately segregated steaks by the probability of a sample being rated “juicy” by consumers, with the actual percentage of “juicy” samples determined to be 41.67%, 72.31%, 89.33%, and 98.08% for the <50%, 50 – 75%, 75 – 90%, and >90% categories, respectively. Therefore, enhancement has a substantial, positive effect on beef palatability. Enhancing higher quality beef does not provide an additional palatability benefit; hence the greatest economic advantage is in enhancing lower quality beef products. Results of this study indicate the PJP juiciness method is both repeatable and accurate at sorting steaks based on the likelihood of a steak being “juicy”.

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Mozzarella cheese is currently the highest consumed cheese in the United States. The popularity of mozzarella cheese is typically attributed to the high consumption rates of pizza cheese and string cheese; both of which are low moisture part skim (LMPS) mozzarella cheese. A single serving of LMPS mozzarella cheese contains approximately 8% of the daily value (DV) for sodium, a mineral which is currently consumed in excess among most Americans. On average, one in three Americans has hypertension. This condition is strongly associated with excessive sodium intake, and it is a leading risk factor for cardiovascular disease and stroke in the United States. Considering the popularity of LMPS mozzarella cheese, its sodium content, and the alarmingly high rates of hypertension among the American population, mozzarella cheese appears to be a product worth pursuing for sodium reduction. Salt (NaCl) provides several key benefits to cheese including: flavor enhancement, preservation, moisture control, and syneresis; thus reducing its concentration in cheese can result in multiple quality concerns. Previous research has investigated the effects of lower sodium in a variety of cheeses including: cheddar, feta, and imitation cheese. Typical methods for reducing sodium content in cheese include reduction of NaCl alone to a level which is still acceptable or partial substitution of NaCl with salt replacers including KCl. For assessing the consumer acceptability of low sodium cheeses, researchers have typically employed the use of traditional hedonic, preference, and ranking questions; however, consumer scientists have recently suggested the benefits of asking consumers questions which go beyond typical acceptability questions. Purchase intent and decision making have been associated with consumer emotions, and perhaps by better understanding consumer emotions toward nutritional alternative foods, including low sodium mozzarella cheese, a more successful low sodium cheese can be developed. The current study implemented a series of tests to progressively understand the role NaCl plays in mozzarella cheese and consumer opinion of low sodium cheese. A series of traditional sensory tests, including triangle, duo-trio, and hedonic tests, were performed to determine a sensory transparent antimicrobial and a consumer acceptable salt replacer. Based upon this sequence of tests, a single antimicrobial (SEA-i F75) and concentration (0.275%) were selected in addition to the most consistently preferred salt replacer in a low sodium mozzarella cheese system; however, the most preferred salt replacer was dependent upon the type of mozzarella cheese (direct acid or bacteria cultured). In order to address the potentially limited information from traditional sensory testing, a novel method for evaluating emotions was developed. The IMET (Image Measurement of Emotion and Texture) method utilized consumer provided images of emotions, researcher generated emotion images, and emotion words (the current industry standard) to aid in emotion testing, and the use of texture images and texture words (industry standard) for texture assessment. The IMET method was tested and validated across three commercial food product categories: orange soda, dairy beverages, and convenience cheeses. The IMET study indicated consumer selected emotion images were less variable than emotion words in a positive emotion, but the words only method was less variable in a negative emotion. Additionally, subjects were more likely to use images of themselves for positive emotions, and images of others for the negative emotions. After validation of the IMET method, the consumer emotion images method was used in conjunction with consumer acceptability testing and instrumental texture analysis in non-commercial low sodium mozzarella cheese. This study indicated the full sodium cheese was consistently liked most, followed by the 100% KCl cheese sample. Additionally, cheese with higher hedonic scores had increased changes in the positive emotions, while the disliked products had increased changes in the negative emotions across the eating experience. The instrumental texture analysis resulted in significant textural differences between the eight samples tested, and samples with higher mean scores for all texture attributes were associated with having higher mean hedonic scores. The studies performed in this thesis are important contributions for better understanding the role of NaCl in LMPS mozzarella cheese, and the consumer’s perception and potential acceptance of this nutritional alternative product. Additionally, the development of a novel emotion testing method may impact how researchers ask consumer questions, conduct consumer research, and investigate the effects of images on emotion testing with consumers.

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