The effect of ultrafiltration, diafiltration, and preacidification of milk on the partition of specific milk components between retentate and permeate was studied. Percent retention (for any component Y) was determined as: [ l - (%Y in soln. permeate/%Y in soln. retentate)] X 100 where %Y in soln. = [%Y/(%Y + %H 20)] Simultaneous samples of retentate and permeate were taken at several points during each process. Percent retention of total solids, fat, total protein, rennet clottable nitrogen, lactose, total calcium, ionic calcium, sodium, phosphorous, and riboflavin was determined at each sampling point. Percent retention of β-carotene, vitamin B12, retinol, and zinc was determined at different stages of ultrafiltration only. As UF proceeded, percent retention of total solids, total protein, total calcium, ionic calcium, sodium, phosphorous, and riboflavin increased. Percent retention of lactose was not affected and was 0-4%. Percent retention of fat, rennet clottable nitrogen, zinc, retinal, β-carotene, and vitamin B12 was 99-100%. As diafiltration proceeded, percent retention of total solids, lactose, total calcium, ionic calcium, sodium, phosphorous, and riboflavin increased. Percent retention of these nutrients was increased when compared to ultrafiltration alone. Milks with lower pH values (resulting from preacidification) also had lower percent retention of total calcium and phosphorous than milks with normal pH values. Percent retention of sodium was lower during ultrafiltration and diafiltration of acidified milk when compared to ultrafiltration and diafiltration of normal milk. Percent retention of other nutrients was not affected by acidification. Loss of whey proteins into permeate resulted in a lower recovery of total protein after diafiltration than ultrafiltration alone and ultrafiltration of acidified milk. These proteins were determined to be α-lactogobulin and β-lactogobulin.

Process cheese models were prepared by blending acid or rennet casein, milk fat, sodium chloride, 2.5% emulsifying salt and water and heating to 80 C. Acid casein cheese models were subjected to sodium hydroxide conditioning at 65 C in the cooker. Model process cheeses were acidified with lactic acid and treated by addition of undenatured and heat-denatured whey protein, four different emulsifying salts and sodium oxalate. Meltability and toughness of the model cheese increased to a maximum with increased sodium hydroxide conditioning of acid casein to pH 7.20. These same properties decreased with addition of undenatured and heat-denatured whey protein to both casein cheese models. Loss of emulsion occurred during the meltability test of rennet casein cheese models with 3.0 and 4.5% added whey protein. Emulsifying salts affected the models differently. Disodium phosphate and tetrasodium pyrophosphate in rennet casein models eliminated the melting property. These same salts in acid casein models produced excellent meltability. Trisodium citrate produced cheeses with good meltability in both acid and rennet casein cheese models. Acid casein cheese models prepared with sodium aluminum phosphate had fair meltability and were very tender (no rupture upon compression). Chelation of calcium by sodium oxalate in rennet casein cheese emulsified with disodium phosphate or tetrasodium pyrophosphate improved meltability with a corresponding increase in toughness. Scanning electron micrographs of model process cheeses indicated a direct relationship between extent of emulsification and poor meltability of rennet and pH conditioned acid casein model cheeses. Acid casein model cheeses prepared with different emulsifying salts did not exhibit this same relationship. Addition of whey protein concentrate to rennet case~n model cheese produced fibrous structures around the fat globules. No structural abnormalities were noted in the acid casein cheeses prepared with whey protein concentrate.

The purpose of this research endeavor was to identify and apply effective strategies to evaluate the efficacy of a university-level general education hybrid nutrition course offered to distance education and on-campus students. A review of relevant literature indicated that student engagement levels, student characteristics, and the use of instructional technology are important to consider when evaluating postsecondary learning environments. Furthermore, the balance of asynchronous and synchronous learning activities within hybrid learning environments should be deemed suitable for the subject matter as well as the receiving student population. Finally, student perceptions and learning outcomes should also be assessed by hybrid course evaluations. The study described in this work established that a standardized general education hybrid nutrition course offered by Utah State University can effectively facilitate learning while generating positive student perceptions from the majority of enrolled distance education and on-campus cohorts alike. All course materials were available online, and were supplemented with weekly, synchronous recitation sessions. Interestingly, the learning outcomes and satisfaction rates of the two student cohorts were similar. However, notable differences in learning preference and performance were identified based on student age alone. Modifications to subsequent versions of the evaluated hybrid course were made based on the findings of the study. Other instructors and course design teams involved in postsecondary nutrition education may view this project as an outline for their own hybrid course development and evaluation efforts, although, limitations did exist and should be acknowledged. An experimental design exhibiting more control over potential extraneous variables, such as instructor, could offer more concrete evidence than the observational nature of the present study. Also, it appears that students' success levels in a given learning environment are not only influenced by instructional measures, but also by the personal and contextual factors of each individual student. Future evaluative efforts should place a greater emphasis on exhibited learning patterns, educational background, and academic discipline of students within the hybrid learning environment. Ultimately, the primary challenge of a modern-day hybrid course is to offer a cohesive and effective blend of uniformity, customization, flexibility, and instructional guidance based on anticipated needs of students.

Vitamin D is hydroxylated to form several active metabolites, of these, 1,25- dihydroxyvitamin D3 [1,25(OH)2D3] is the most studied stimulatory product. It is now accepted that 1,25(OH)2D3 mediates its rapid actions on the control of phosphate homeostasis through its membrane receptor 1,25D3-MARRS (membrane associated rapid response steroid binding) protein. Another metabolite, 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] has been reported to be inhibitory with respect to calcium and phosphate absorption in intestine. Previous work in this laboratory has indicated that 24,25(OH)2D3 inhibits phosphate uptake in isolated intestinal cells and perfused duodenal loops and in vivo. This thesis further tested the hypothesis that the actions of 24,25(OH)2D3 on phosphate homeostasis are physiologically important. Catalase has been identified as a binding protein for 24,25(OH)2D3. We determined the localization of catalase in the presence and absence of steroid, monitored catalase mRNA levels related to gene 24,25(OH)2D3 gene transcription regulation. We studied the effects of the two isomers of 24,25(OH)2D3 on localization of catalase in chicken enterocytes over a time course of 15 sec to 60 min. It was demonstrated that 24R,25(OH)2D3 is the effective metabolite for catalase redistribution in vitro. We also studied the effects of vitamin D on catalase and phosphate uptake in chicken intestinal cells. It was once again demonstrated that 24R,25(OH)2D3 is the effective metabolite for decreasing phosphate uptake and catalase gene expression. These combined results lead us to conclude that 24,25(OH)2D3 is an important hormone in phosphate homeostasis in chick intestinal epithelial cells.

The influence on eating quality of beef of cooking method, sires, mineral (Fe, Mg, Zn, Na, K, and P), lipid, and nitrogen content was determined by objective measurements, sensory evaluations, cooking losses, and chemical analysis. Two adjacent arm and two adjacent rib roasts from 18 Herford animals were used. The arm and rib (sixth to eighth ribs) roasts were deboned, cut in half, and randomly assigned to the conventional or electronic ovens for dry roasting to the medium-rare stage (145 F, 147 F). Roasts of the ninth to twelfth ribs were dry-roasted in a meat research oven at 325 F to an internal temperature of 155 F. The Warner-Bratzler shear test determined tenderness to be greater in conventional roasts, Press fluid amounts were similar for both ovens. Cooking losses were greatest in the electronic oven. The taste panel judged conventional roasts to have better flavor and to be more tender and juicy. Laboratory analysis of minerals indicated specific ones influenced the tenderness of beef, Lipid content was found to be significantly correlated with juiciness, tenderness, shear force, and percentage drip. The findings showed nitrogen to affect juiciness inversely and the cooking losses positively. High correlations for roasts containing the ninth to twelfth ribs were indicated for flavor, tenderness, and shear force; also tenderness was judged by the taste panel with shear force, and press fluid with cooking loss.

Nutritional problems of var ious population groups throughout the world are constantly being emphasized, It has been pointed out that life expectancy at birth is only thirty to forty years for over half of the world's population , while for those people who have been able to take advantage of modern medical and nutritional science, it is sixty five to seventy years, Hunger, as well as preventing economic advancement, promotes unrest and political upheavals. The United States, in the interest of preserving its own security and way of life has a vital stake in solving world nutritional problems as well as its own. Without doubt, we are all aware of this need today of improving the nutritional needs of our own people in practically all parts of the United States. However, the nutritional needs have to be defined before improvements can be recommended. More exact and reliable criteria are needed for identifying borderline cases of malnutrition for various groups of people. This problem is gradually being solved through correlated medical, biochemical, and dietary studies. Thus, as one of the criteria on which to rely, dietary studies are one of the means of measuring the nutritional adequacy of the diet. An evaluation of the school lunch by means of a dietary study cannot be made without also considering the other foods eaten during the day. The benefit of a good school lunch to health and dietary habits, therefore, may be greatest for those children whose family food supplies and habits are the poorest. The benefit will be greatest in the extent to which the foods provided in the school lunch supplement those supplied in the home. A study of the dietary habits of school children in terms of the nutritive value of the school lunch and the rest of the day's food would help to evaluate the nutritional status for the group studied and measure the effectiveness of the school lunch program for improving the dietary habits of the children. Since the school lunch and its contribution tot the total day's diet had not been studied in Utah, seven-day dietary records of the 8th grade Logan Junior High and 8th and 9th grades Wellsville Junior High students were used in evaluating the nutrient intake of the children. The purpose of this study was to determine the contribution of each meal ( breakfast , noon meal , and evening meal) to the total day's diet with emphasis on children eating school lunch versus the children not eating school lunch . The between-meal foods were also studied to see to what extent this supplementary intake improves the overall adequacy of the adolescent's diet .

Physically active females, or female athletes, are at risk for the condition knownas the female athlete triad (Triad). The Triad is made up of three components that are distinctly separate, but intertwined: consuming inadequate energy for how much they are exercising, poor bone health, and problems with their menstrual periods. When female athletes don’t consume enough energy for how much they exercise, there can be hormonal imbalances, causing the body to conserve energy from some important functions including menstruation, and increased bone turnover resulting in a higher risk of stress fractures and early osteoporosis. Female athletes at risk for the Triad have ahigher risk of being injured, and don’t have the energy that they need to perform physically. To combat the Triad, we performed assessments to see how many female athletes were at risk for the Triad in Division I female athletes, and were surprised at the high number that were at risk for the Triad. We provided nutrition information and interventions aimed to decrease female athlete’s risk for the Triad. We also developed anew, quick method for female athletes, or busy individuals, to track their diet using the video feature on their cell phones. The benefits of providing nutrition information to the female athletes included: increasing their knowledge about the Triad, and things that they could do to prevent the Triad. The interventions did cause behavior change in some female athletes to increase how much energy they were consuming, decreasing their risk for the Triad.

Barley, cornstarch, crested wheatgrass, glucose, molasses and solka floc were fermented with rumen fluid obtained from sheep that were adapted or unadapted to feed grade biuret (Kedlor) in their diet. Each rumen fluid and substrate combination was subjected to three nitrogen treatments: (1) control, (2) nitrogen added as feed grade biuret and (3) reagent grade biuret in a factoral arrangement of treatments. In vitro fermentations were terminated at 0, 12, 24, and 36 hours and the protein nitrogen insoluble in trichloroacetic acid (TCA) was determined. Molasses and cornstarch fermentation residues increased while barley, crested wheatgrass, glucose and solka floc decreased in TCA insoluble protein nitrogen. The average of all treatments decreased in TCA insoluble protein nitrogen during the first 12 hours and increased during the remaining 24 hours. Unadapted rumen fluid with simple carbohydrates from glucose and molasses and adapted rumen fluid with complex carbohydrates from barley, crested wheatgrass, cornstarch and solka floc gave the largest gains in TCA insoluble protein nitrogen. No significant differences occurred due to the addition of non-protein nitrogen.

We explored using de-oiled algal biomass (algal cake) as a low-value substrate for production of lactic acid in fermentations with Lactobacillus casei, and strategies for increasing lactic acid production at low pH. L. casei 12A algal cake (AC) fermentations showed carbohydrate and amino acid availability limit growth and lactic acid production. These nutritional requirements were effectively addressed with enzymatic hydrolysis of the AC using α-amylase, cellulase, and pepsin. Producing 0.075 g lactic acid per g AC from AC digested with all three enzymes. We explored heterologous expression of the cellulase gene (celE) from Clostridium thermocellum and the α-amylase gene (amyA) from Streptococcus bovis in L. casei 12A. Functional activity of CelE was not detected, but low-level activity of AmyA was achieved, and increased > 1.5-fold using a previously designed synthetic promoter. Nonetheless, the improvement was insufficient to significantly increase lactic acid production. Thus, substantial optimization of amyA and celE expression in L. casei 12A would be needed to achieve activities needed to increase lactic acid production from AC. We explored transient inactivation of MutS as a method for inducing hypermutability and increasing adaptability of L. casei 12A and ATCC 334 to lactic acid at low pH. The wild type cells and their ΔmutS derivatives were subject to a 100-day adaptive evolution experiment, followed by repair of the ΔmutS lesion in representative isolates. Growth studies at pH 4.0 revealed that all four adapted strains grew more rapidly, to higher cell densities, and produced significantly more lactic acid than untreated wild-type cells. The greatest increases were observed from the adapted ΔmutS derivatives. Further examination of the 12A adapted ΔmutS derivative identified morphological changes, and increased survival at pH 2.5. Genome sequence analysis confirmed transient MutS inactivation decreased DNA replication fidelity, and identified potential genotypic changes in 12A that might contribute to increased acid lactic acid resistance. Targeted inactivation of three genes identified in the adapted 12A ΔmutS derivative revealed that a NADH dehydrogenase (ndh), phosphate transport ATP-binding protein PstB (pstB), and two-component signal transduction system (TCS) quorum-sensing histidine kinase (hpk) contribute to increased acid resistance in 12A.

Underreporting in dietary assessment has been linked to dietary restraint (DR) and social desirability (SD). Thus, this study investigated accuracy of reporting energy intake (EI) of a laboratory meal during a 24-hour dietary recall (24HR) in 38 healthy, college-aged (20.3 +/- 1.7 years), normal-weight women (22.4 +/- 1.8 kg/m2), categorized as high or low in DR and SD. Participants consumed a meal (sandwich wrap, chips, fruit, and ice cream) and completed a telephone 24HR. Accuracy of reported intake = (((reported intake - measured intake)/measured intake) x 100) [positive numbers = overreporting]. Overreporting of EI was found in all groups (meal accuracy rate = 43.1 +/- 49.9%). An interaction of SD x individual foods (p < 0.05) occurred. SD-High as compared to SD-Low more accurately reported EI of chips (19.8 +/- 56.2% vs. 117.1 +/- 141.3%, p < 0.05) and ice cream (17.2 +/- 78.2% vs. 71.6 +/- 82.7%, p < 0.05). An effect of SD occurred, where SD-High as compared to SD-Low more accurately reported meal EI (29.8 +/- 48.2% vs. 58.0 +/- 48.8%, p < 0.05). For measured meal EI, an effect of DR occurred where DR-High consumed less than DR-Low (437 +/- 169 kcals vs. 559 +/- 207 kcals, p < 0.05). An interaction of DR x food type (p < 0.05) occurred where DR-High as compared to DR-Low consumed less sandwich wrap (156 +/- 63 kcals vs. 210 +/- 76 kcals, p < 0.05) and ice cream (126 +/-73 kcals vs. 190 +/- 106 kcals, p < 0.05). For reported meal EI, an effect of DR occurred where DR-High reported consuming less than DR-Low (561 +/- 200 kcals vs. 818 +/- 362 kcals, p < 0.05). An interaction of DR x individual foods (p < 0.05) occurred where DR-High reported consuming less ice cream than DR-Low (145 +/- 91 kcals vs. 302 +/- 235 kcals, p < 0.05). Overreporting EI from a laboratory meal was prevalent. However, those high in SD were more accurate in reporting intake, particularly of high-fat foods. Future research is needed to investigate factors that contribute to overreporting.