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Utilizing summer annual grass-legume forage mixtures has the potential to improve forage yield and nutritive characteristics, and/or animal performance during times when cool-season pasture growth is limited by high temperatures. Legumes can utilize atmospheric nitrogen, which can increase crude protein and forage digestibility in mixtures. As nitrogen application generally improves both the yield and nutritive characteristics of summer annual forages, but can have a negative effect on legume competitiveness, nitrogen fertilizer recommendations for legume-containing summer annual mixtures are not well established. Two experiments were conducted to determine the feasibility of utilizing summer annual mixtures in Kentucky, USA. The first experiment was a small plot study. The objective was to evaluate the effects of increasing botanical diversity and N application rates on the yield, botanical composition, and nutritive characteristics of summer annual forage mixtures. The second experiment was a grazing study that evaluated the effects of increasing summer annual species diversity on forage yield and nutritive value, and animal performance. In the first experiment, N rates of 0, 56, 112, 168, and 224 kg N ha-1 were applied to a sudangrass monoculture, a three-species mixture, and an 11-species mixture. Sward biomass in three out of four environments increased as N application increased (average of 14 kg DM ha-1 per kg N ha-1; p < 0.05). As all treatments were dominated by grass species, mixture complexity had no effect on forage DM accumulation for three out of four environments (4000, 5830, and 7280 kg DM ha-1 averaged over N rates for three environments; p > 0.05). Swards were dominated by sudangrass and pearl millet (73 and 24% in simple mixtures, and 62 and 22% in complex mixtures, respectively), resulting in low functional diversity, likely due to high grass seeding rates. Mixture complexity also did not affect most nutritive characteristics (p > 0.05). Although N application up to 224 kg N ha-1 often had a positive impact on forage quality parameters, forages in three out of four environments would not support the nutritional demands of growing or lactating cattle when averaged across harvests. A sensitivity analyses showed that applying N resulted in positive net returns only when hay prices were very high and N prices were low. When pasture utilization rates and hay feeding/storage losses are accounted for, enterprise budgets determined grazing to have 10% greater expenses than haying. In the second experiment, yearling angus-cross beef calves were assigned to graze one of three summer annual forage treatments, a sorghum-sudangrass monoculture, a simple three-species mixture, or a complex 12-species mixture. Animals grazed for an average of 40 days per year without supplementation. Forage yield was not different between treatments (P > 0.85). Although several forage quality parameters were affected by mixture, none provided useful insight into differences observed in average daily gain (ADG). In 2017 and 2019, calves grazing the monoculture and simple mixture had higher ADG than calves grazing the complex mixture (2017: 0.79 vs. 0.66 kg/day, P < 0.03; 2019: 0.59 vs. 0.43 kg/day, P < 0.03). In 2018, there were no differences in ADG (P > 0.3); however, calves only gained 0.01 kg/day, possibly due to lower nutritive value of more mature forages. Forages in 2018 were abnormally tall and calves were observed to be flightier and more agitated. The added stress of a low-visibility environment may have contributed to poor gains. Taller forages may also have limited dry matter intake and/or sward utilization since calves could not reach the top of the plants. In these studies, increasing species diversity did not improve forage yield, nutritive characteristics, or animal performance. This was likely due to heavy grass competition and poor legume establishment. If sward diversity is of interest, care must be taken to select compatible species, utilize appropriate seeding rates, and implement management that will promote less well-adapted species. Under the constraints of these experiments, utilizing summer annuals in forage systems in Kentucky would only be economical when hay costs were high, when production costs were low, and when animal performance was enhanced.

Personality tests are utilized to characterize individual differences in personality traits across species. Currently, there is no objective personality test that can be implemented on-farm to measure personality in dairy calves. Measuring personality of youngstock in the dairy industry may allow producers to utilize information on individual differences for management decisions and limit the investment in unfit individuals. The isolation box test is a personality test that has potential to be adapted and utilized for dairy calves. The main objective of this thesis is to develop, validate, and utilize an isolation box test for use on-farm in dairy calves. More specifically, the objectives of this thesis are to determine if an isolation box test can determine individual differences in dairy calves, if outcomes from the isolation box test agree with outcomes of established standardized personality tests, and if outcomes from an isolation box test can predict performance outcomes through weaning in dairy calves. The measures produced from an isolation box test were associated with outcomes of standardized personality tests (novel person, novel object, and startle tests) and growth through weaning. The isolation box test has potential to be used as a personality test in dairy calves on-farm.

The transition period is commonly defined as the last 3 wk before parturition to 3 wk after parturition. It is the most critical stage of the lactation cycle of high-producing dairy cows. The period consists of a complex interplay of metabolic and hormonal adaptations, inflammation, and immune activation. During the transition period, dairy cows commonly face oxidative stress, an underlying factor for dysfunctional immune response and enhanced inflammation, which can further increase the susceptibility of dairy cattle to health disorders and decrease productivity. In the last few decades, there has been an increased interest in studying alternative natural compounds with antioxidant and antiinflammatory properties as supplements for food-producing animals such as dairy cows. The aim of this project was to evaluate the effects of carnosic acid, a phenolic diterpene found in herbs from the Labiatae family, known for its antioxidant and antimicrobial properties, on both in vivo and in vitro models. The first objective was to evaluate the supplementation of carnosic acid on performance parameters and blood biomarkers of transition dairy cows. The findings of this study revealed that carnosic acid promoted positive responses on inflammation and expression of oxidative stress biomarkers during the period of infusions. In addition, carnosic acid tended to increase lactation performance (e.g., milk yield and energy corrected milk), although the mechanisms responsible for this response remain unclear. The second objective was to evaluate the protective effects of carnosic acid on cultured mouse hepatocytes in response to oxidative challenge. This in vitro study revealed that carnosic acid promoted increased viability and antioxidant capacity through superoxide dismutase activity of mouse hepatocytes subjected to hydrogen peroxide-induced oxidative cell damage. In summary, the presented results reveal potential benefits of providing antioxidants such as carnosic acid during periods of oxidative challenge, such as the peripartal period of dairy cows.

In this study, a novel value-added dairy-based health formulation was developed using whey protein hydrolysate and probiotic organisms. In the first part of the study, different forms of whey proteins, concentrate WPC80, isolate WPI90, and hydrolysates WPH10, WPH15 and WPH20 were screened for bioactivities (antimicrobial, antioxidant, and antihypertensive activity). Hydrolysate WPH10, exhibiting the highest bioactivities was conjugated with maltodextrin. A batch of 2L conjugated solution was spray dried in a Niro drier with an inlet and outlet temperature of 200⁰C and 90⁰C, and alternatively, freeze dried at −80 °C under 50 mTorr vacuum. The bioactivities of the conjugated samples were then assessed. Overall, the hydrolysates showed significantly higher bioactivities as compared to concentrate and isolate. The conjugated WPH10 solution demonstrated higher antimicrobial, and antioxidant activity, whereas no significant difference in the antihypertensive activity was observed, as compared to WPH10 alone. Subsequent spray and freeze drying of the conjugate solution exhibited even higher antimicrobial, and antioxidant activities, while retaining the antihypertensive activity. Overall, the results indicate the ability of the WPH-maltodextrin to retain the bioactivities after conjugating with a reduced carbohydrate. In the second part of the first study, conjugated whey protein hydrolysate (WPH10), was used as an encapsulant to entrap probiotic cultures; Bifidobacterium animalis subsp. lactis ATCC27536 and Lactobacillus acidophilus ATCC4356, through a spray drying process. Each culture was added in the conjugated solution at ratio of 1:1, with spiking level of 10 log CFU/mL. The mixture was spray dried in 2L batches using a Niro drier with an inlet and outlet temperature of 200⁰C and 90⁰C, respectively. Following drying, scanning electron microscopy was used to observe the particle structure of the WPH10 conjugate. Following, the dried formulation was stored in airtight bottles for 16 weeks at 4°, 25° and -18°C, to monitor cell viability, moisture, and functionality. From the micro images it was observed that subsequent drying, nonconjugated WPH10 presented link bridges between the powder particles, whereas in case of conjugated WPH10, the particles presented a round surface with pores on it. The mean counts in conjugated WPH10 matrix before and after drying were 10.59 log CFU/g and 8.98 log CFU/g, respectively. At the end of 10 weeks, the counts were 7.18 log CFU/g at 4°C and 7.87 log CFU/g at -18°C, whereas at 25°C the viability significantly decreased to 3.97 log CFU/g. At this point, the wetting time increased from 47min to 61min, and solubility decreased from 90% to 82%. In the second study, whole-genome sequencing was done to determine the genotypic variants and associate with phenotypic expression in Listeria strains. Genomic DNA was extracted from the strains (Listeria innocua 634-2; Listeria innocua 634-34-S- 5; Listeria innocua 634-34-S-6; Listeria welshimeri 634-3; Listeria welshimeri 634-253- S-5, and Listeria monocytogenes 315-S-1), isolated from the dairy processing environment and run through Whole-genome sequencing on the Ilumina MiSeq and Nanopore sequencing platform. The genome was fed into the RAST database to develop the annotations. The results revealed 13 types of phenotypic responses related to the genotypic variants. Overall, the genotypic variants varied with the species and within the strains. Some of the common variants and features identified in the isolates were virulence (DNase, phage terminase, tRNA-Arg-ACG), cell signaling (NAG-IIA, NAGIIB), phage immunity (CRISPR proteins), osmotic stress (CadA), oxidative stress (YRKL), and antibiotic resistance (BaiE, Lde). L. monocytogenes was positive for all the phenotypic characteristics, allowing it to be more persistent, whereas L. innocua and L. welshimeri isolates lacked variants for motility (ActA), biofilm formation (AgD), and acid tolerance (AdiA), making them more sporadic strains.

This study aimed to evaluate the transcriptomic profile of both corium tissue from lactating dairy cows experiencing sole ulcers and skin lesions from lactating dairy cows diagnosed with digital dermatitis (DD). Hoof biopsies were performed in multiparous Holstein dairy cows selected based on their condition as clinically healthy or diagnosed with sole ulcers (n=7/group). Similarly, skin biopsies were taken from the center of active (M2/M4.1) DD lesions or non-active (M0/M4/M1) from multiparous Holstein dairy cows (n = 7/group) to assess the impact of DD on the skin transcriptome via RNA-seq analysis. All RNA samples were sequenced using Illumina, NovaSeq S4 at the University of Minnesota Genomics Center. Principal component analysis (PCA) and analysis of variance for each gene was calculated using the DESeq2 package in R to determine the differentially expressed (DE) genes, fold change (FC), and P-value based on the comparison of sole ulcer (SU) over healthy cows (HC) and digital dermatitis (DD) over apparently healthy (HDD). The DE genes with at least  2-fold change were retained for an enrichment pathway analysis using gene ontology (GO) terms and the enrichGO function in the Clusterprofiler package in R. The FDR cut-off value was set to < 0.01. The PCA analysis clearly discriminated the hoof transcriptomes between HC and SU cows. The number of DE genes in SU and HC was 10,274 ± 22 and 10,289 ± 36 (mean±SD), respectively. Several genes coding for keratins (e.g., KRT34 and KRT85) were downregulated (FC < -15) in SU cows, while the highest upregulated (FC = 10.9) gene in SU was IL6. The GO analysis showed significant downregulation of GO terms in SU cows compared to HC in the Cellular Component category, including intermediate and keratin filaments and intermediate filament cytoskeleton. Upregulated genes in SU cows resulted in a significant enrichment of GO terms in the Biological Process category, including extracellular matrix organization and vasculature development, and GO terms in the Cellular Component category such as extracellular matrix and cell surface. The GO terms enrichment across biological process, cellular components, and molecular function categories were highly involved in the keratinization process, inflammation, and transcriptional regulation. These processes are crucial for the development of sole ulcers causing lameness in dairy cows. Similarly, in the case of digital dermatitis also, the PCA analysis clearly discriminated the skin transcriptome between DD cows and NA. Genes coding for several keratins-associated proteins, including KRT34, KRTAP21-1, and KRTAP4-9, were downregulated in DD cows. The GO terms associated with downregulated genes in the Cellular Component category were mainly correlated with collagen-containing extracellular matrix and keratin filament, while GO terms in the Biological Process category were related to humoral immune response and biomineral tissue development. Upregulated genes were highly enriched in the Molecular Function GO terms of cell-adhesion and skin development as well as intermediate filament cytoskeleton in the Cellular Component category. Overall, this skin transcriptome evaluation comparing NA and DD cows identified key biological pathways in which there was a dysregulation in the skin extracellular matrix, encompassing the keratinization process, collagen binding, and immune response caused by DD lesions. This transcriptomic dataset captures the molecular adaptations in the development of sole ulcer and bovine DD. In the future, this information could be further utilized to generate nutritional and management strategies to reduce this infectious disease.

Phospholipids (PLs) found in milk are of great interest due to their health and nutritional benefits associated with their consumption. By-products generated during the manufacture of dairy products represent a source of PLs with potential for value-added opportunities. Currently, the extraction of PLs from by-products results in overall lowefficiencies, and it involves subsequent solvent separation and lipid recovery. This dissertation studied the extraction of milk PLs from by-product streams with a tertiary anime (N, N-dimethyl cyclohexylamine, CyNMe2) as a switchable hydrophilicity solvent. This type of solvents can be reversibly switched between a hydrophobic and hydrophilic form in the presence or absence of CO2. Different dairy by-products streams, including buttermilk (BM), beta-serum (BS), concentrate buttermilk (CBM), and raw cream (RC) was used to evaluate the feasibility of CyNMe2. The extraction efficiency of CyNMe2 ranged from 0.33-99%, depending on the type of byproduct. Remarkably, CyNMe2 extracted up to 99% of the PLs directly from buttermilk. The extraction of PLs from BS was further studied using ultrasound prior to CyNMe2 extraction. Overall, higher levels of acoustic intensity (44.56 ± 3.47 W cm-2) prior to CyNMe2 extraction recovered 69.07 ± 0.11% of PLs, 10-fold higher than the samples without ultrasound pretreatment. The recovered fraction of PLs mainly comprised of phosphatidylinositol (32%), phosphatidylethanolamine (30%), and sphingomyelin 37%). The effect of the extraction temperature (25, 40, and 60oC), time (3, 10, and 18 h) and solvent ratio (3/1, 10/1, and 18/1 mL) was also studied. The highest yield obtained was 29.29 ± 0.06% of PLs at 60 oC, at minimized solvent ratio and time (3/1 mL and 3 h, respectively). At these conditions, the fraction of PLs recovered was phosphatidylinositol (59%) and phosphatidylethanolamine (35%). Insights into the extraction mechanism of the CyNMe2 was studied through various analytical measurements, such as analysis of protein-profile, particle size, zeta potential, and microstructure, Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). CyNMe2 seems to disrupt the protein-membrane through ion pair formation, releasing the PLs into the aqueous medium. Throughout this thesis, CyNMe2 shows to be an effective way to concentrate PLs from by-products.

This Master thesis evaluates the impact of general health care and eating habits (Study 1), vision care (Study 2), and mental health status (Study 3) on Latino dairy farmworkers lifestyle and work performance in South Dakota. We hypothesized that the health status of dairy workers has a negative impact on the workers’ job performance. In study 1, data from a total of 70 participants were collected, using a face-to-face survey in Spanish, which allowed us to assess various topics and details related to employees’ daily routine tasks, eating habits, and general health status. Furthermore, recommendations to improve general health care were given at an educational workshop at the end of the survey period. The most participants were males (76%); the mean age of participants was 28 ± 1.7 and 34 ± 1.6 for female and male, respectively. The majority of the participants were Mexican (46%) and Guatemalan (44%) workers. The majority (80%) do not have health insurance; over half of them have not seen a physician in the last 3 years, and 65% have not seen a dentist in the last 6 months. Also, over half (53%) of the interviewed workers were overweight or obese (mean BMI = 25.6 ± 4.2 kg/m2). Workers living in the U.S. for up to four years had BMI = 25 kg/m2, whereas the BMI of those who had been in the U.S. for a long time was higher ( > 28 kg/m2). One-third reported sleeping between four to six hours a day and 46% reported eating in restaurants at least twice a week. They usually opted for healthier choices when arriving in the U.S.; however, their food habits change throughout the years with more fast food or frozen food consumption due to their convenience. In Study 2, 90 participants were enrolled for vision screening to identify visual impairments. Demographic data using a survey was collected. Almost one-fourth needed further eye examination and 43% had never been seen by an eye care provider either due to the cost of eye care or due to the language barrier. Among the participants that needed an eye exam, 60% were milking parlor workers. A full detailed report of pupillary diameter, ocular alignment, binocular refraction, and referral recommendation (e.g., anisometropia, hyperopia, strabismus, myopia, astigmatism, and anisocoria) was provided to participants at the end of the study. In study 3, 50 dairy farm employees participated in a Focus Group (FG) for a qualitative study. A total of 7 FG sessions were conducted, 5 FG with 3 commercial dairy farms, and 2 FG in 2 different communities with dairy workers. Transcriptions of the FG were analyzed and coded line by line for each quotation and question using ATLAS.TI software (Scientific Software Development GmbH). Most of the participants were males (88%), and 54% were Mexicans, 30% Guatemalans and 16% other Latin American countries (e.g., El Salvador, Honduras, and Nicaragua). Participants were asked to share stress-causing factors in their workplace, at home, and in their community. Additionally, participants shared information on the strategies they apply or consider useful in reducing stress. Physical changes experienced due to stress, the main causes of their insomnia, and the meaning of stress in one word were included. Results show that over 35 factors were contributing to overall stress at the workplace, at home, and in the community, which were also qualitatively identified. Personal health care and mental health were influenced by individual values, culture, motivation, environment, and community. Overall, employee’s well-being may impact their job performance in a negative way. Strategic workshops designed to promote health education and healthy eating habits for farmworkers are needed in their native language.

Mastitis is considered one of the most common and costly diseases in the dairy industry. Intramammary infection status at a herd level is measured using somatic cell count (SCC). Understanding the total cost of an elevated somatic cell count can help influence dairy farmers to lower SCC and select management practices to produce higher quality milk. The first objective of our research was to determine if the cost of an elevated somatic cell count to farms can be decreased through the adoption of management practices with varying expenses. Using stochastic simulation modeling, the adoption of three differently priced management practices were modeled in herds with varying somatic cell counts. Results were highly dependent on whether a premium scheme for lower SCC milk was in place and how close a herd’s initial SCC was to a premium level. When herd SCC reduced enough to receive a premium, the total cost of SCC to the farm was dramatically reduced. One management practice that has historically been used in the industry is treating every quarter of every cow with an intramammary antibiotic at the end of her lactation. However, future restrictions of antibiotic use in animal agriculture may pressure dairy farmers to treat only cows with an intramammary infection at the end of the lactation. The second objective of our research was to complete an economic analysis comparing the total cost of dry cow therapy in simulated dairy farms when every quarter of every cow was treated with intramammary antibiotics compared treating only cows with an intramammary infection at end of the lactation. Results from the model indicate the treating every quarter of every cow at the end of lactation was most economically feasible in simulated farms. However, as the cost of a case of mastitis and mastitis incidence decrease, treating only cows with an intramammary infection may become economically feasible. Within recent years, the dairy industry in the Southeastern United States has shown interest in changing the way milk is priced. Currently, dairy farmers in the Southeast are paid for total fluid volume and butterfat, while other areas are paid for milk fat, protein, and other solids yields. The third objective of our research was to determine the differences in milk value using the conventional milk pricing system compared to a multiple component pricing system using cow production records. After examining average milk values, multiple component pricing may result in Southeastern dairy farmers being paid more for their milk.

Compost bedded pack barns utilize composting methods which provide a soft surface for dairy cows to lie on. This requires optimal microbial growth, which may increase the exposure of mastitis-causing pathogens to the teats of early lactation animals. Bedding characteristics, bedding bacteria, and bacterial counts on the teat skin, teat ends, and in the milk of early lactation dairy cows housed on a compost bedded pack were assessed over a 6-month time. The main objective was to determine the relationship between environmental effects (bedding characteristics and weather conditions) and cow-level (teat skin, teat end, milk) bacteria counts over time in transition cows. A secondary objective was to assess CBP characteristics across time and what environmental factors influence bedding bacteria counts. The final objective was to determine if various stages of the transition period (2-weeks prepartum, 72-hours postpartum, 60 days in milk) influenced the cow-level microbial populations.

The transition period is the dynamic stage in the lactation cycle, where the most metabolic changes can occur. The use of nutritional strategies, such as yeast culture, can help cows during the transition from pregnancy to early lactation, improving health and decreasing the incidence of metabolic disorders. The first objective of this research was to evaluate the effects of a commercial yeast culture product (YC; Cellerate Culture Classic HD, Phibro Animal Health, Teaneck, NJ) on performance, blood biomarkers, and rumen fermentation and bacterial population in dairy cows during the transition period through 50 days in milk (DIM). Overall, the results showed that yeast culture products could promote positive responses on performance, such as milk yield, somatic cell count (SCC), and energy corrected milk (ECM). In the rumen, yeast culture product contributed to increased valerate, which was accompanied by improvements in rumen bacteria populations such as cellulolytic and lactic acid-utilizing bacteria. In addition, the results suggest that yeast may influence lipid metabolism in transition dairy cows, based on nonesterified fatty acid (NEFA) and beta-hydroxybutyrate (BHB) markers. The second objective was to assess the effects of yeast-based products on metabolism, inflammation, liver function, and immune function through blood biomarkers and gene expression in polymorphonuclear leukocytes (PMNL) in dairy cows during the transition period until 50 DIM. Yeast supplementation might stimulate a mild inflammatory response in transition dairy cows, based on blood biomarker and PMNL mRNA expression. In summary, we observed that yeast culture could promote improvements in performance, rumen bacteria population, and stimulate the immune system in transition dairy cows through 50 DIM.

It is a common practice in dairy industries to nanofilter milk protein concentrate (MPC) to increase the solids and further drying efficiency. Increasing protein and solids in MPC increases viscosity and resist feed-flow in membrane filtration. Previous research proved that increased temperature and hydrodynamic cavitation (HC) have significantly reduced the viscosity of MPC which can potentially increase the level of solids by reducing concentration polarization during nanofiltration (NF). We utilized plate and frame filtration (PF) as an alternate method to reduce the viscosity of MPC. In first objective, we studied the application of HC or elevated temperature (50˚C) or both to concentrate MPC with 80% protein (MPC80) based on total solids (TS) using NF. Three replicates of MPC80 having 20% TS were concentrated in NF system at 22 and 50˚C. HC did not have a significant impact on average flux but increased the TS significantly. Study showed that increased temperature or its combined action with HC improves NF performance in MPC filtration. In second objective, we studied the functionality of MPC80 powder after spray drying of NF retentates from first objective. Study showed that, higher temperature NF impacted on rennet coagulation time (RCT), wetting time, and heat coagulation time of the powders. Both HC and elevated temperature did not impact on flowability and emulsion capacity whereas HC alone improved dissolution and foaming capacity of the powders. Study showed that NF temperature and HC have important impacts on the functionality of MPC80. In third objective, we studied the application of PF in MPC80 concentration at 22 and 50˚C using flat-sheet ultrafiltration membrane. Average flux, final TS, and total protein to TS ratio were increased significantly at higher temperature PF. Study showed that increased temperature improves PF performance in MPC filtration. In fourth objective, we studied the functionality of MPC powders after spray drying of feed and PF retentates from third objective. Higher temperature PF impacted on RCT, wettability and solubility but improved foaming capacity and emulsion stability of the powders. Study showed that temperature optimization is important for concentrating MPC80 in PF system to maintain its functionality.

As a result of their extended shelf-life, dried dairy ingredients constitute a significant category produced for global markets. During the development of dairy ingredients, several drying trials are typically conducted to determine optimum drying conditions. The results of these trials can be critical in determining optimum dryer design. However, these trials can be expensive and time-consuming. An alternative that has recently been developed using a new technique called single droplet drying (SDD). The SDD technique involves a single droplet suspended on the tip of a glass filament, where changes in droplet diameter, mass, and temperature are measured during drying. SDD makes it possible to create a pictorial view of the drying process. Once the drying process is complete, particle morphology can be determined using microscopy, or the rehydration behavior can be visually studied. A predictive model generated using SDD can then be used to optimize the drying conditions and dryer design. The modeling will help reduce costly plant trials and accelerate the development of new ingredients with novel functionalities. Hence, the Single Droplet Dryer (SDD) was installed at SDSU to conduct the bench-top trials. The aim of the first study was to study the effect of different solids concentration on the drying kinetics of whey protein concentrate by using SDD. There was a significant (P< 0.01) change in the diameter, mass, and temperature change profiles during the drying run between 10%, 20%, and 30% total solids level for the WPC80. These activation curves are independent of the initial droplet sizes and constant drying conditions but dependent on the initial total solids’ concentration, hence calculated separately for each level of total solids. The viscosity of the WPC80 solution significantly (P < 0.01) increases with an increase in the total solids level. There is a correlation between the particles obtained from the semi-commercial spray dryer and the particle generated on the SDD. Scanning electron microscopy, in conjunction with SDD, completely avoids commercial spray drying run to observe a particle and study the morphology of newer materials. The second study was conducted to compare the differences in the drying kinetics of Micellar Casein Concentrate (MCC) vs. Modified (CO2 induced) MCC, due to the difference in the composition of both the materials. Due to the differences in the pH and mineral balance between MCC (pH ~ 6.7) and Modified MCC (pH ~ 5.7); and the presence of the higher amount of de-aggregated casein micelle in the modified MCC, there was a significant difference (P< 0.01) observed in the drying properties like change in moisture removal pattern, mass change of the particle, and temperature change pattern during the drying run. Materials with higher viscosities, higher total protein, and higher total solids, and minor differences in composition can be compared and studied on SDD. The objective of the third study was to understand the dissolution behavior of the dried particle of the infant formula at two different temperatures, viz: 70°C and 110°C. The outlet temperatures of the dryer have a significant effect (P< 0.01) on the rehydration properties of dried powder. We have observed a significant difference (P< 0.01) in the diameter change/ moisture removal pattern, mass change, and temperature change between 70°C and 110°C, two different temperatures of drying at all the solids level viz., 15%, 40%, and 50%. The change in total solids for each temperature had a significant (P< 0.01) effect on the properties of the dried particle. We observed better rehydration/ higher solubility (P< 0.01) of the powder particle of Infant Milk formula dried at 70°C temperature compared to those dried at 110°C. The dissolution times for each total solid at 70°C are significantly (P< 0.01) different than those at 110°C for corresponding total solid values. Hence, the functionality of dairy powders is affected by the outlet temperatures of the dryer.

Ever growing demand for dairy products in many countries has led to advancements in the manufacture of such products. Nowadays, revolutionary trends for high-protein dairy foods and drinks products have brought about new challenges from processing requirements and manufacturing aspects. Using different membrane processing has enabled dairy manufacturers to produce different fraction of milk proteins such as micellar caseins, ultra-filtered (UF) milk proteins, whey proteins concentrate (WPC), and micellar casein concentrate (MCC) to meet the nutritional needs with variety of milk product options. However, the installation of new processing lines and establishing further manufacturing steps requires more consumption of water and raises in the generation of waste streams and byproducts. Dairy wastewater is defined as a biomass with high biological oxygen demand (BOD), chemical oxygen demand (COD), nutrients, organic and inorganic materials. Therefore, dairy wastewater requires multifaceted treatment prior disposal into the municipal sewage system to avoid environmental jeopardies. In this research, the valorization of two main biomass streams from dairy manufacturing have been discussed – ice cream wastewater and whey permeate. Ever growing demand for dairy products in many countries has led to advancements in the manufacture of such products. Nowadays, revolutionary trends for high-protein dairy foods and drinks products have brought about new challenges from processing requirements and manufacturing aspects. Using different membrane processing has enabled dairy manufacturers to produce different fraction of milk proteins such as micellar caseins, ultra-filtered (UF) milk proteins, whey proteins concentrate (WPC), and micellar casein concentrate (MCC) to meet the nutritional needs with variety of milk product options. However, the installation of new processing lines and establishing further manufacturing steps requires more consumption of water and raises in the generation of waste streams and byproducts. Dairy wastewater is defined as a biomass with high biological oxygen demand (BOD), chemical oxygen demand (COD), nutrients, organic and inorganic materials. Therefore, dairy wastewater requires multifaceted treatment prior disposal into the municipal sewage system to avoid environmental jeopardies. In this research, the valorization of two main biomass streams from dairy manufacturing have been discussed – ice cream wastewater and whey permeate. been recognized as a promising method for conversion of ice-cream wastewater into valuable chemicals such as surfactants, foaming agents, emulsifiers, and animal feed. Hydrolysis ice-cream wastewater under subcritical treatment (230˚C, 40 bar, and 240 min) reduced its organic materials significantly (87-97 and 25-70% of the BOD and COD, respectively). Moreover, the subcritical process hydrolyzed 38 to 56% of the protein fraction, and the resulting hydrolysates showed antioxidant activity (14-19% of the DPPH) and antihypertension (ACE) activity (60-97%). Additionally, the hydrolysates contained a high ratio of glutamic acid (20-26%) and proline (10-15%), which confirmed the relevant functional properties. Whey is the main byproduct obtained from the manufacture of cheese, yogurt, and milk protein concentrates. After separation of whey proteins through membrane processing, the remained stream is known as whey permeate, and it contains a considerable amount of lactose (75–80% on dry basis). As a feedstock, lactose has the potential to undergo different reactions leading to the formation of value-added compounds. The simultaneous production of lactulose (LAU), lactobionic acid (LBA), and organic acids from sweet and acid whey permeate (SWP and AWP) via catalytic synthesis (5% Ru/C) was studied in a continuous stirred-tank reactor. At selected conditions (60˚C, 60 bar, and 600 rpm), a maximum conversion of lactose (37 and 34%) was obtained after 90 min for SWP and AWP, respectively. The highest yield calculated with respect to the initial concentration of lactose for LAU was 22.98 ± 0.81 and 15.29 ± 0.81% after only 30 min for SWP, and AWP, respectively. For LBA, a maximum yield was found in SWP (5.23%) after 210 min, while about 2.2% was found in AWP. Six major organic acids (gluconic, pyruvic, lactic, formic, acetic, and citric acid) were quantified during the one-pot synthesis of lactose. The synthesis of a pool of molecules through a one-pot approach represents an alternative approach for the utilization of streams of lactose. Upon further separation, organic acids can be used as building blocks of numerous applications in the manufacture of herbicides, bioplastics, and biofertilizers.

Delactosed permeate (DLP), commonly referred to as mother liquor, is a plentiful byproduct in the dairy industry. It is a direct byproduct of edible lactose manufacture produced in cheese and dairy ingredient facilities. Despite being rich in lactose and minerals, DLP is most commonly relegated to an animal feed product due to its high ash content, it inhibits and disallows crystallization of any remaining lactose. Delactosed permeate showed many inconsistencies from supplier to supplier and within lots from the same supplier in the eight DLP samples obtained from four separate mozzarella and cheddar manufacturing facilities. Nanofiltration (NF) opens potential food applications for DLP. The eight DLP samples obtained were processed via NF creating two separate product streams. A retentate (NFR) with increased lactose concentrations on a dry basis in addition to increased concentrations of large molecular weight minerals and organic acids (Ca, Mg, S, citric acid). In addition to, a permeate rich in small molecular weight minerals and organic acids (Cl, Na, K, lactic and formic acid). Flux rate and the composition of retentates/permeates varied from trial to trial and is likely due to different milk compositions, cheese making practices, whey handling practices and lactose manufacturing methods.

Growth of higher protein dairy products and ingredients such as cheese, Greek yogurt, whey protein concentrates, and milk protein concentrates is limited by the amount of co-product generated and the ability to process them into value added ingredients. Finding value for all the co-products will help dairy industry to meet the growing demand for dairy protein products and ingredients. Commercial scale evaluation of new technologies for improving lactose crystallization and drying ability of Greek yogurt acid whey will help dairy industry to better utilize different dairy co-products. Commercially, lactose is manufactured from concentrated permeate by cooling and separating α-lactose monohydrate crystals. Factors that impact crystallization of lactose during cooling will influence the yield of lactose. Caking and powder stickiness are major challenges during drying of Greek yogurt acid whey or Greek acid whey (GAW), because of high acidity, high mineral concentration, and relatively low protein content in it. The first objective of this study was to evaluate commercial feasibility of using Soluble Soybean Polysaccharide (SSPS) to improve lactose recovery during manufacture of lactose from permeate. Previous research has demonstrated that lactose crystallization could be modified by using SSPS in pure lactose solutions. However, commercial lactose is typically manufactured by crystallization of concentrated permeate (CP). A laboratory scale crystallization set up with parallel crystallizers was utilized to conduct control and treatment experiments simultaneously. Lactose recovery with 0.1% SSPS addition was significantly (P < 0.05) higher (76.31%) as compared to the control (71.33%). Out of the total SSPS added to the treatment solution, 79.82% was recovered into the wash water. The findings of this study suggest potential feasibility of SSPS for enhancing lactose crystallization during lactose manufacture from concentrated permeate. The objective of the second study was to evaluate commercial feasibility of using SSPS to improve the drying ability and powder characteristics of GAW. The composition of GAW is considerably different from that of cheese whey making it difficult to process into powder ingredients. The high lactic acid and mineral content in GAW delays lactose crystallization which causes stickiness during spray drying and caking during storage of the powder. The first study had shown that soluble soybean polysaccharide (SSPS) can enhance lactose crystallization in concentrated permeate. However, the effect of SSPS on the crystallization of lactose in concentrated GAW has not been evaluated. GAW obtained from a Greek yogurt manufacturer was vacuum concentrated to 56% total solids (30% Lactose) and crystallized using a laboratory scale crystallization tank. After crystallization, the concentrate was spray dried using a pilot scale NIRO dryer. GAW powder yield (51.87%) with 0.1% SSPS addition was significantly (P < 0.05) higher compared to that of GAW without SSPS (44.51%) and observed to be less sticky on the dryer surface. The findings of this study indicate that SSPS can enhance lactose crystallization in concentrated GAW during crystallization, reduce the sticking of the caking of the GAW powder. The objective of the third study was to evaluate the feasibility of partial demineralization and deacidification of GAW by nanofiltration (NF) to improve the drying ability and powder characteristics of GAW. Greek yogurt acid whey (GAW) contains high concentrations of lactic acid (LA) and minerals as compared to cheese whey. The LA and the minerals, particularly the Calcium (Ca) in GAW cause stickiness during spray drying, thus limiting the processing and utilization of GAW. Nanofiltration (NF) has been in use to for partial removal of minerals from cheese whey and milk to produce high value-added dairy ingredients. Similarly, NF can potentially be applied for partial demineralization and deacidification of GAW to improve spray drying and powder properties. By NF processing, the lactic acid and total ash concentrations were reduced significantly (P < 0.05) by 34.3±0.2 and 37.8±0.7, respectively. The reduction of monovalent ions, i.e., sodium and potassium were observed to be higher (66% and 62%) than that of calcium (41%). GAW-NFR powder yield (56.35%) was significantly (P < 0.05) higher compared to that of GAW (44.51%) and observed to be less sticky on the dryer surface. The findings of this study indicate that partial demineralization and deacidification of GAW using NF can improve the spray drying characteristics of the GAW powder. The objective of the final study was to evaluate the effect of addition of SSPS to NFR-GAW on the drying characteristics of the GAW. In this study, the yield, and drying characteristics of GAW with and without 0.1% SSPS were compared. There was no significant (P > 0.05) difference observed between the yields of GAW-NFR (56.35%) xvi and GAW-NFR with SSPS addition (58.24%). However, the yield of NFR-GAW (56.35%) was significantly (P < 0.05) higher than that of GAW with SSPS addition (51.87%). From this study it can be concluded that there may not be any additional advantage in addition of SSPS to NFR-GAW in improving the spray drying characteristics of GAW.

The phenomenon of hydrodynamic cavitation involves the formation, growth, and subsequent collapse of bubbles when a given liquid experienced a reduction of pressure below its vapor pressure. The presence of cavitation limits the performance and the safe operation of many machinery and pumps. However, innovation in the design of the hydrodynamic cavitation devices has offered promising applications in the food and dairy industry. Upon collapse of the cavities, the fluid experiences significant mechanical effects (shear and turbulence) as well as instantaneously elevation of the fluid temperature. All these effects can be put to work for mixing, dispersion, particle size reduction, disinfection, and emulsification. In this thesis, the feasibility of using a rotational cavitator for different unit operations was systematic evaluated. The feasibility of hydrodynamic cavitation was evaluated in terms of analysis of cavitation parameters, characterization of the increase in the fluid temperature, microbial efficiency, and emulsification of ice cream mix. The analysis of the cavitator revealed that the velocities generated inside the rotational cavitator are sufficiently high to induce cavitation within the fluid. The development of the cavitation was influenced by the flow rate, speed of the rotor, temperature, and fluid properties. The pressure at which cavitation would first appear was calculated as a function of the operating parameters. The increase in the temperature of the fluid was modeled, showing satisfactory correlation with the experimental data. The increased in the temperature of the fluid due to cavitation was used to develop a process for assisting thermal pasteurization with the idea of reducing the log counts of thermoduric bacteria. The newly developed process can be operated within a wide range of processing conditions (50-300 L h-1, 600-3600 RPM, 70-85°C with residence time from 10-110 s). It was found a 3.5 log reduction of Bacillus coagulans by cavitation followed by thermal treatment, while thermal treatment along yielded a 2.77 log reduction. The hydrodynamic cavitation was applied during the manufacture of ice cream with the idea of reducing the concentration of stabilizers. Particle size of ice cream mix and rheology test was conducted to determine the influence of the stabilizer amounts in ice cream mix. Hydrodynamic cavitation itself reduced the particle size of cream and ice cream mix. Dynamic rheological measurements (strain and frequency sweeps) of ICM indicated increased product stability at a rotation speed of 3600 RPM and flow of 100 L -1. However, the mechanical spectra were considerable different. Imparted viscosities at medium shear rates were at least 2-fold greater compared to formulations homogenized conventionally.

The ability of high intensity ultrasound to produce stable emulsions without the addition of surfactant was evaluated in a dairy-based formulation. The formulation consisted of protein (4.33 ± 0.05%, whey protein concentrates (WPC80), carbohydrates (21.52 ± 0.75%, sucrose and maltodextrin), oil (2.90 ± 0.05%, soybean oil), and surfactant (0-.05%). Pre-emulsions formulated with either 0, 0.025, and 0.05% of soy lecithin were treated for 5 min at an acoustic intensity of either 42.58 ± 2.98, 56.83 ± 3.01, or 70.48 ± 2.97 W cm-2. The stability of the emulsions was evaluated through particle size, dynamic rheology, gel electrophoresis, and microstructure. In general, the particle size decreased with the acoustic intensity (397 to 230 nm), regardless of the concentration of soy lecithin. Dynamic rheology (strain and frequency sweeps) showed an improved stability of the emulsions treated at 56.83 ± 3.01 and 70.48 ± 2.97 W cm-2 without the addition of soy lecithin, displaying a distinctive viscoelastic region and a behavior of weak gel. During 21 days of storage at 4°C, the particle size slightly increased (470-500 nm), while the mechanical spectra remained essentially unchanged. High intensity ultrasound offers opportunities for reducing surfactants in dairy-based formulations.

In cold temperature storage, Parmesan cheese can develop an undesirable browning defect. Certain pyrazine compounds converted from methylglyoxal have been identified and associated with the brown pigmentations in Parmesan cheese samples. This study focused on creating a cheese model system to study variables that caused browning and variables that helped reduce or alleviate browning. The cheese making steps for the cheese model system were monitored by measuring pH and TA and the final composition for % fat, % moisture, % salt and pH. Additionally, the cooling curve was studied to ensure all wheels of cheese made were cooled similarly. Cheese made in the experiment were then used in a slurry as part of the cheese model system to test variables such as aging temperature, heat abuse, addition of NSLAB, addition of adjuncts, addition of galactose, addition of methylglyoxal and modified %salt and pH. This study identified variables that contributed to browning which included: aging temperature (55°F), addition of methylglyoxal, NSLAB addition, heat abuse and time. Increased browning was observed over time, the most after 3 months, at 55°F in the presence of methylglyoxal and heat abuse. These findings were verified by testing these variables at different ages using a colorimeter. The variables studied to understand how to reduce browning included addition of NSLAB (Lb. helveticus), addition of adjuncts (lb. plantarum and Lc. lactis diacetylactis) and modified environment of high %salt and low pH. The cheese model system had a % salt of 2.19 and a pH of 5.60 which was modified to 3.00% for high salt and 5.20 pH, all samples were aged at 55°F. Reduction of browning was achieved using both adjuncts and modified environments of high salt and low pH. The greatest reduction in browning was observed when Lb. helveticus and Lb. plantarum were added together as a treatment and had a small Delta E (color change) of 0.92. The adjunct, Lc. lactis diacetylactis also reduced browning, average Delta E of 1.89 in the presence of Lb. helveticus, high %salt and low pH. The most effective way to reduce browning was achieved using adjuncts and modified environments of high salt and low pH.