Selective removal of fat from acid whey during whey protein concentrate manufacture : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Technology in Food Technology

The purpose of this study was to develop a low cost technology for selective removal of lipids from acid whey during whey protein concentrate manufacture Attention was focused on gaining a better understanding of the structure and composition of the lipids in whey and ultrafiltration retentate The effects of varying dilutions, pH, salt concentration, temperature and holding time on the flocculation of lipids in the whey and retentate were investigated The composition and structure of lipids in acid whey and retentate were determined by ultracentrifugation, compositional analysis, integrated light scattering and confocal scanning laser microscopy (CLSM) techniques. Acid whey contained ~ 0.034% lipids The size of the milk fat globules (MFG) in whey varied from 0.1 and 10 μm. with the majority of the globules < 1 μm in diameter The retentate contained ~ 0.36% lipids The size of the MFG in the retentate ranged between 0.1 and 20 μm. generally larger than the MFG in the acid whey Investigation into the removal of lipids from acid whey revealed that flocculation of MFG in the acid whey occurred at temperatures between 40 and 50°C and at pH values from 5.8 to 7.0. It was observed that under these conditions, high-density lipid containing flocculent/precipitates was formed, which subsequently sedimented upon centrifugation (at 1126/g for 10 min) The MFG removed in the flocculent/precipitate appears to be either part of a calcium-MFG complex or MFG entrapped by precipitation of calcium precipitate Examination of the effects of physiochemical factors on the flocculation of MFG in between the retentate revealed that flocculation occurred upon dilution and at pH values between 4.5 and 4.7. It was found that at increasing dilutions, there was an increase in the removal of MFG and in the retention of protein in the supernatant. At retentate dilution of 1:6, the majority of the MFG was removed and a majority of protein was retained in the supernatant Flocculation of MFG in the diluted retentate was influenced by ionic strength (at Low pH values) of the system. This flocculation is thought to result from the hydrophobic association of proteins of MFGM, aggregates of serum proteins, lipoprotein complexes or individual denatured serum proteins Low fat whey protein concentrate powder (WPC) was produced on a pilot-scale plant using the process conditions determined at the laboratory scale to remove MFG from acid whey retentate. The resulting product contained ~ 1% fat. considerably less than the normal commercial WPC On a dry basis the protein content was ~ 96% as compared to ~ 85% in the commercial WPC Examination of the functionality of the low fat WPC revealed the heat-induced gels formed from 15% WPC were more elastic, had better water holding capacity, and were more "gelatinous" in nature Their gelation properties were markedly superior to the commercial WPCs currently manufactured Based on the results of this study, recommendations are made on possible areas of process improvement and development opportunities

Why the undergraduate mechanical engineering curriculum needs reform

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 32).The addition of a systems engineering concentration through the MIT Mechanical Engineering Alternative (course 2A) curriculum will be shown to have the potential to increase the number of engineering degrees in comparison to non-engineering degrees, to better prepare MIT engineering graduates, and to increase the percentage of graduates that pursue careers in engineering rather than finance and consulting. Original data was collected from Careerbridge and used along with existing information available through the registrar and careers office to provide a quantitative breakdown of the trends in Mechanical Engineering department enrollment, degrees awarded, and skills demanded of graduating alumni. These results are used to suggest that the number of MIT Mechanical Engineering graduates can increase by recognizing the existence of a type of engineer defined as the Systems Engineer. Systems Engineers are currently switching out of engineering into business, finance and consulting, and this can be corrected through a concentration in 2A similar to an existing program called the Gordon Engineering Leadership Program.by Arron Acosta.S.B

Changes and relationships of soil aluminum, organic matter, and hydrogen ion concentration with rye cover crop

Soil acidity is a common agricultural problem worldwide, as approximately 50% of all potentially arable soils are affected by pH limitations. At soil pH 3+) is considered to be the chemical form of aluminum in acid soil that hinders plant growth the most. Potentially, soil organic matter (SOM) can ameliorate the toxic effects of Al3+ on plants and microbes by binding with Al3+, thus preventing Al3+ (and other species of aluminum) from interacting in the rhizosphere. Increasing SOM also increases soil health indicators (i.e., microbial activity, soil water holding capacity, aggregate stability, porosity, etc.) while the management of SOM is relatively inexpensive. Wintertime cover crops (WCC) are commonly used for increasing SOM (and for other soil benefits). This study hypothesized that increased SOM from the growth of a WCC could potentially reduce Al3+ concentrations by binding Al3+ to the SOM. This study attempts to fill a knowledge gap regarding the relationship between cover crops, SOM and Al3+, as few (if any) field-scale tests on this subject have been published. In this before-after field study, a WCC of annual rye (Lolium multiflorum) was grown in a 0.4-ha field between November 2020 to July 2021 and then mowed. During this time, soil analysis was carried out for SOM percentage, Al3+ concentration, and pH. These variables were analyzed using paired t-tests and linear mixed effects regression. Random effect terms were added to the linear regression analyses to account for spatial and temporal variability in field conditions. Paired t-tests indicate a significant decrease in hydrogen (H) ion concentration (t = 2.1858, df = 16, p-value = 0.04404, n = 18), a marginally significant increase in SOM ( t = -1.8972, df = 16, p-value = 0.076, n = 18), and a marginally significant increase in Al3+ (t = -1.8741, df = 16, p-value = 0.0793). H ion concentration decreased significantly between wet (December 2020) and dry (September 2021) seasons (t = 2.1545, df = 16, p-value = 0.04678). Using linear mixed effect regression (LMER), H ion and nitrate (NO3-) were found to have significant effects on Al3+ concentrations (conditional R2=0.41), Al3+ and NO3- were found to have significant effects on H ion concentration (R2 = 0.35), and H ion and phosphorous (P) were found to have significant effects on SOM (R2 = 0.54). The fit for the last model is moderate and further inquiry could be made to predict SOM with these (and other) variables. While heterogeneity of the study site and mixed results are limitations, this study offers evidence that use of annual rye WCC may be an effective tool for maintaining SOM and pH. This study concludes that soil pH has a stronger effect on Al3+ concentration than does SOM. This concept further refines the understanding of the limitations of SOM in relation to soil pH, especially with regards to managing soil fertility and soil carbon sequestration on croplands and rangelands

Exploring Surfactant and Plasticiser Segregation in Thin PVA Films

Surfactant segregation in solid polymer films is a little studied area of scientific research. This investigation launches an initial exploration into the behaviour of surfactant and plasticiser (glycerol) molecules in a poly(vinyl alcohol) (PVA) matrix. By understanding the nature of segregation within these systems, information regarding the compatibility of components can be gained. A greater understanding of what dictates compatibility and small molecule segregation in polymers is of importance to many industrial products and processes. Using a series of ion beam analysis and neutron reflectometry experiments the segregation behaviour of three non-ionic, and two ionic surfactants is studied in great detail, both in binary non-plasticised and ternary plasticised PVA films. In order to use these techniques effectively, samples were mostly spin-cast, silicon substrate bound polymer films, of thickness <200 nm. The non-ionic surfactants studied were a series of poly(oxyethylene glycol) alkyl ethers with a 12-carbon lipophilic tail-group (C12Ex). Each of these surfactants exhibited spontaneous segregation to the air and/or substrate interface of the polymer film in binary films with PVA. Upon the introduction of plasticiser under ambient conditions, the amount of surface segregating surfactant is reduced, causing a greater concentration to be present in the bulk. However, when studied under relative humidity control the opposite effect is realised, and the presence of water in the films causes increased surfactant segregation. The ionic surfactants studied are cetlytrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS). In binary films with PVA, CTAB shows no segregating nature, until glycerol is introduced, at which point substrate and surface segregation is induced. SDS shows development of significant surfactant-plasticiser multi-lamella structures on the surface of the thin films upon the introduction of the glycerol. SDS-glycerol structures like this, with interstitial regions of plasticiser stabilising the surfactant lamellae are unlike anything seen on the surface of a solid polymer film before. Both of these features infer a complex array of interactions with the plasticiser. Surface energy and compatibility arguments are provided throughout to explain the diverse range of surfactant behaviours discovered in this work. Where surface energy is believed to be the driving force of surface segregation, with lower energy components segregating more, and compatibility to be the force which dictates how segregation behaves upon the introduction of plasticiser. Compatibility arguments are mostly comprised of the hydrogen bonding potential of the compounds within the films, where strong interactions between the polymer, plasticiser and surfactant give rise to increased compatibility, and therefore reduced segregation. Through this work, new, exciting information on the nature of small molecules in polymer systems is realised

Arabophobia and Arab-Conscious Hip-Hop

Designation of Arabs as the quintessential Other in America is considered in response to events witnessed on September 11, 2001. Cowardly, menacing, violent – are words used to describe 9/11. American popular culture, not surprisingly, has used the same words to describe Arabs for decades. American popular culture has always undermined Arabs’ existence. Distorted images of Arabs have become a part of the American visual psyche, influencing education, politics and policies. Therefore 9/11 to an extent provided the framework for systemic discrimination against Arabs and those assumed to be Arabs. My essay advances a definition of Arabophobia, calling for differentiation between racial discrimination and religious discrimination, i.e., Arabophobia and Islamophobia. Arab hip-hop artists in response to criminalisation of Arabs and wars in the Middle East, I argue, have taken up a quintessential American medium to enter the popular discourse surrounding Arabs and counter the dominant narrative dictating Arab lives. Arab-conscious hip-hop is the actualisation of a cultural protest by Arabs for better representation. Instead of being portrayed by apathetic popular culture, Arab artists challenge the same culture and create conditions and possibilities for social change. Arab-conscious hip-hop counters Arab stereotypes with potential to educate audiences and (re)construct the Arab identity. In the essay I discuss the song “P.H.A.T.W.A.” by The Narcicyst. Elements of the song I present reconstructs the Arab identity by reclaiming symbols of discrimination, the same way African Americans did with hip-hop in the 80’s, and berating American for using 9/11 as an excuse for fascist wars and institutional discrimination. The Narcicyst, through “P.H.A.T.W.A.,” creates a sense of consciousness for socio-political transformation

Where The Border Ends: How Reactive Policies to Terrorism Became Conduits for Drone Technology and the Enclosure of Wealthy Nations

The Antiterrorism and Effective Death Penalty Act (1996) and the USA PATRIOT Act (2001) are two key examples of reactive policies enacted in response to terrorist attacks on American soil. Expedited passage of both pieces of legislation were reliant on the public’s support for government action in wake of recent atrocities. These acts gave particular attention to securing the nation’s borders, directing an increase in funding for Border Patrol in order to prevent future terrorist attacks. This essay will connect the increased funding for border security directed by Congress with the defense industry’s pursuit of funding and outlets for drone technology, to the export of the national security state model and the expansion of borders via drone technology. The arms race that ensues as a result of this restructuring of the global order directly connects to a new form of imperialism, expanding borders without the necessity of troops on the ground through the utilization of drone technology. Expansion and blurring of borders occurs when wealthier nations utilize a poorer nation’s airspace for terrorism deterrence missions using drone technology. This essay finds that this new form of imperialism creates a de facto open-air prison out of much of the impoverished world; one that is under constant unmanned aerial surveillance by wealthy nations as they simultaneously enclose themselves under the doctrine of national security

An Evaluation of Performance as it Relates to Leadership Training in the United States Coast Guard

Problem. Training programs that focus on leadership and management are becoming more prevalent in society with little regard to the training’s impact. This study’s purpose was to determine if there was a relationship between leadership training and performance in the United States Coast Guard. Method. The sequential mixed-method study examined the impact o f a 33-day resident training course on the graduate’s performance. The measurement o f performance was obtained quantitatively through annual performance evaluations and qualitatively through interviews. The performance evaluations were collected from 40 graduates of the Coast Guard C hief Petty Officer Academy and analyzed using a repeated measure analysis o f variance. The study spanned 4 years, collecting one pre-graduation evaluation and three post-graduation evaluations. For the qualitative portion of the study, four Chiefs were examined with interviews in an effort to expand on the impact o f the leadership training. Results. The results of this study indicated that leadership training significantly increased overall performance as measured through performance evaluation (p \u3c 0.01). The portions o f the performance appraisal that significantly increased were the leadership abilities and organizational responsibilities sections (p \u3c 0.01), whereas the military protocol and professionalism section showed no significant increase (p \u3e 0.05). Although leadership training positively impacted performance, the effect was found to be minimal. Conclusion. The Chief Petty Officer Academy was designed to teach newly promoted Chiefs the leadership and communication skills they need to be successful in their new position. While it was not specifically designed to improve performance, it appears that it has that effect. The Chief Petty Officer Academy could capitalize on this positive effect by focusing aspects o f its curriculum more directly on performance-enhancing training, making the program more beneficial to the United States Coast Guard