Browsing by Subject "Food science"

On a planet with shrinking natural resources and a rising population, who will have enough to eat? This research studies the people and policies involved in an emergent citywide system of food waste recuperation in the E.U.’s capital of Brussels. It incorporates those who recirculate food—such as volunteers at the city’s largest food bank; workers at a culinary skills-training program; and activists in a soup kitchen with "zero food waste" weekly pop-up restaurant. It also includes those who benefit from their efforts—such as the E.U.'s growing immigrant and refugee population, some of whom strive to become citizens while others pass through on their way to larger dreams of European belonging.

The same policy drives these efforts, but distinct ethical frameworks guide them. Reflecting the city’s Catholic history, traditional hospitality is embodied in acts of sharing food—which adherents believe builds communities, brings individuals closer to God, and reinforces the belief that God will provide. Volunteers at the food bank strongly express this ethic. Elsewhere, acts of “giving back” become ways to recruit new citizens, expressing neoliberal politics that locate an ethic of caring within capitalism. For example, a job-training program is a restaurant that runs on donated food and offers internships to welfare recipients so that they might join the local labor force one day. Finally, an N.G.O. runs a social inclusion program aimed at recuperating not only abandoned food but also abandoned urban spaces. In this case, a mobile soup kitchen aims to revitalize urban blight through feeding the city’s hungriest residents—giving sustenance by means of scrappy collaborations between volunteers, citizens, and immigrants.

Through ethnographic observation, this dissertation explores sharing food as a way of caring for people that reflects moral beliefs about value and worthiness, both of food as well as of people. It asks: How do obligations of care square with social obligations that match cast-off food with cast-out humans?

Dietary intake is one of the most complex and sustained environmental exposures of the human lifespan. At present, field standard methods for dietary assessment all depend on asking people to self-report what they eat. Self-reported dietary data have enabled the study of diet-health relationships and informed decades of nutritional policy, but they are also limited in their ability to collect data from individuals across the spectrum of age, cognitive ability, and culture. To address the need for alternative measures of diet, we leverage DNA sequencing technology to measure diet from degraded food DNA in human stool samples. This strategy, termed “DNA metabarcoding,” works by amplifying and sequencing regions of the genome to identify foods by their DNA sequence. Although metabarcoding strategies have been applied in other diet-related fields, they have never been used in nutritional epidemiology.

In Chapter 1, I describe the potential of DNA metabarcoding for human dietary assessment. In Chapter 2, we apply DNA metabarcoding with the chloroplast trnL-P6 marker region to >1,000 stool samples from >300 unique participants. Across multiple cohorts, we find that the number of plant taxa detected per sample by trnL metabarcoding correlates with dietary diversity and quality estimates from established self-report assessments. In a cohort where the administration of self-reports failed, we use trnL metabarcoding to retrospectively derive diet data, and detect relationships between trnL dietary diversity and age, socioeconomic indicators, and health that replicate prior epidemiologic findings.

In Chapter 3, we perform a pilot study of a second molecular technique— metaproteomics— to determine if it can address a key limitation of metabarcoding: the inability of DNA to distinguish food type for foods like chicken and egg, which are derived from the same source species. We identify tissue-specific protein signatures of food intake and confirm an overall correspondence between DNA- and protein- based dietary assessment in comparison to written records. We also expand our metabarcoding protocols to include the mitochondrial 12SV5 marker for combined detection of plant and animal intake. Taken together, these findings establish the value of molecular measurements from stool as a strategy to monitor and improve nutrition.

Polycyclic aromatic hydrocarbons (PAHs) are compounds ubiquitous in the environment and are harmful to human health. PAHs can easily enter the human body through the consumption of edible oils due to their high lipophilicity. Most of the published papers investigating PAH concentrations in edible oils focused on virgin (i.e., unheated) samples instead of those being used in cooking at temperatures higher than room temperature. This study aimed to provide a comprehensive landscape of PAH concentration in soybean oil by simulating a more realistic scenario of oil consumption—eating oil being cooked at different temperatures. I quantified the concentration of PAHs in soybean oil after being heated to four temperatures (100°C, 150°C, 190°C, and 222°C) with three durations (5 minutes, 30 minutes, and 60 minutes). Liquid liquid extraction (LLE), tandemly followed by solid phase extraction (SPE), were used to extract PAHs from the matrix and remove interferences from the extract. PAH concentrations were determined by a gas chromatography mass spectrometer (GC-MS). With extended heating time, concentrations of ACE and FLU showed a rising trend in 100°C and 150°C data groups but a falling trend at higher temperature data groups. Concentrations of PHEN and ANTH had a sharp increase when the oil was heated to 222°C and held one hour. Concentrations of B[a]A, CHRY, and B[a]P rose slightly with extended heating time at almost all temperatures. Concentrations of ACY, FLTH, B[b]F, B[k]F, IND, D[ah]A, and B[ghi]P were low and nearly undetectable. Only NAP concentrations in 100°C-oil samples were over the maximum residue level (MRL) set by China’s national standard. Diverse concentration changes of different PAHs after the oil was heated suggested that B[a]P alone or a combination of several PAHs are not sufficiently representative to be the marker or surrogate for PAH exposure. This diversity also resulted in an undetermined correlation between the PAH remaining in the oil and heating temperatures and hold time. The information of PAHs increment caused by heating soybean oil was incomplete because of data unavailability for the vaporized part.

Background: Nutrition and dietary patterns are one of the most crucial healthcare concerns, especially because of the close association with chronic diseases, such as obesity, diabetes, hypertension and cardiovascular disease and some cancers. Our study focused on the Lumbee Native American tribe of North Carolina, who have diet-related health conditions and susceptibility to chronic diseases. Our study aimed to identify the dietary patterns of the local community both Lumbee Indians and non-Lumbees living in the area and provide recommendations for future programs and policies. Methods: Our descriptive study explored dietary patterns (food groups and food categories) in Robeson County, NC. We used the National Health and Nutrition Examination Survey (NHANES) Food Frequency Questionnaire to record dietary information. We evaluated participants’ knowledge level of hypertension using the Hypertension Knowledge Questionnaire (HKQ). Results: We enrolled 277 participants, of whom 115 (50.6%) were Lumbee and 112 (49.3%) were non-Lumbee. Most of our participants were female (n= 137; 58%) with a median age of 68.39 (IQR 63.0 -76.0). The comparison of data from our participants and NHANES 2005–2006 reported significantly lower frequency intake among participants for fruits, vegetables, dairy, snacks, mixed dishes, and both alcoholic and nonalcoholic beverages (p<0.05). Our participants had a high consumption frequency of sugar-sweetened beverage in average (2.03 times per day). The consumption frequency of fruits, vegetables, grains, dairy, protein, oil and fat, and sugar was not significantly different across race or chronic disease status (p>0.05). Differences by gender was observed in the average consumption frequency of vegetables (3.46 times per day for female vs. 3.11 times per day for male), fruits (1.92 times per day for female vs. 1.82 times per day for male), and grains (2.47 times daily for male vs. 1.75 times daily for female). Most of our participants could answer more than 16 out of 25 questions on the HKQ correctly, while the correct rate for some food-related questions such as pickles and crackers were relatively low. Conclusions: People of different races and chronic disease status in Robeson County shared a similar dietary pattern in general, which was characterized by a low consumption frequency of fruits, vegetables, and dairy products compared with NHANES 2005–2006. While efforts are needed to address the health disparity in Robeson, policymakers should consider the unique role of the female in education and communication of dietary information. Stronger policies are needed to restrict consumption on low-nutrient and energy-dense food to improve the dietary pattern.