In the U.S., youth experience health problems due to inadequate eating behaviors. In terms of physical environmental factors and social environmental factors, youth encounter problems with accessing good foods, as do other age groups. The purpose of this study is to find the relationship between youths’ eating behavior, especially patterns of visiting food resources, and the availability of food resources by food type and socioeconomic background in Providence, Rhode Island. In order to test the relationship between the availability of food resources and socioeconomic situation and children’s eating behaviors, several statistical models are developed. The models are based on the multinomial logistic regression model. Students’ activity data were obtained from a survey in Teen Activity and Transportation Enterprise Project (TATE) under direction of Dr. Talia McCray from September 2006 to May 2007. The food resources location data are collected from the Providence Plan and the Yellow Pages in Rhode Island. The multinomial logistic model shows that the availability of healthy food resources within walking distance from home, frequency to visit food resources, gender, employment status, and race significantly affect access to unhealthy food resources (p < 0.05). The availability of unhealthy foods within walking distance, the number of members living in the household, the number of cars in household, students born in the U.S.A, and the father born in the U.S.A, are not significant. In terms of availability of healthy foods around the home location, number of healthy food resources matter. / text

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Heat transfer to canned particulate laden Newtonian fluids was studied during free axial agitation thermal processing in a pilot STOCK retort which was modified to simulate the can motion in continuous turbo cookers. Evaluation of heat transfer coefficients (overall, U and fluid to particle, hfp) associated with canned liquid/particle mixtures, while they are subjected to free axial motion is difficult because of the problems involved with attaching temperature measuring devices to liquid and particles without affecting their normal motion. A new methodology was developed to evaluate U and hfp in Newtonian liquids. The methodology involved first correlating U and hfp as a function of input variables for cans in fixed axial mode of rotation in which both particle and fluid temperatures were measured using thin wire thermocouples. Subsequently, only liquid temperatures were measured in cans using wireless sensors in the free axial mode, and hfp values were empirically computed from the developed correlations and the measured temperatures. An L-16 orthogonal experimental design of experiment was carried out to select system and product parameters that significantly influence hfp and U for particles in the Newtonian liquid. With significant parameters selected, a response surface methodology and two full factorial experimental designs were used to relate U and hfp to process variables in each mode of rotation (fixed and free axial modes). / Dimensionless correlations were then developed using the evaluated data for heat transfer coefficients (U and hfp), in canned high viscosity Newtonian liquids (with and without particles) using stepwise multiple non-linear-regressions of significant dimensionless groups. In free axial mode, combining the natural and forced convection, Nu = A 1(GrxPr)A2+ A3(Re) A4 (Pr)A5 FrA 6 (rhop/rhop1)A 7 (e/100-e)A8 (dp/Dc) A9 (Kp/K1)A10 yielded a higher R2 (0.93) than using a pure forced convection model when particles were present in the can. Even in the absence of particles, and with the end-over-end mode of agitation where forced convection dominates, introducing natural convection term (GrxPr), improvedR2 from 0.81 to 0.97. Artificial neural network (ANN) models were also developed for heat transfer coefficient predictions and the trained models gave better predictions than dimensionless correlations. All ANN models developed could be implemented easily in a spreadsheet as either matrices or a set of equations.

Changing environments are challenging access to wild foods; resources, which are valued by Inuit for health benefits, often surpass that of available market foods. Community freezer initiatives are gaining popularity as one option to help support wild food access, and thus food security, in northern Canada. Little information exists, however, about how these initiatives help facilitate wild food access for residents. A case study was undertaken in Nain, Nunatsiavut to understand: (1) how the Nain community freezer influences access to wild foods; and (2) key factors that community freezer management could consider to better support food security in their communities. Results indicate characteristics of the socio-cultural, economic, and natural environment are challenging wild food access for Nain community freezer users. Factors for consideration in future management include: issues of supply, dependency, social exclusion, and tensions between the feasibility of operations and the representation of traditional values.

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The effects of irradiation dose (0, 0.5 and 1.0 kGy), various gas atmospheres and storage temperature (5, 15 and 25$ sp circ$C) on the physical, chemical, microbiological, and organoleptic changes in fresh pork were studied using factorial design experiments. The effects on toxin production by Clostridium botulinum were also investigated using challenge studies. Shelf life could be extended to 21 d when product was packaged in 0% O$ sb2$, irradiated at 1.0 kGy and stored at 5$ sp circ$C compared to 4 d for control samples. While the presence of O$ sb2$ in the package headspace enhanced the antimicrobial effects of low-dose irradiation, it adversely affected the organoleptic qualities of pork. Botulinum toxin was detected after only 2 d in all inoculated treatments stored at 25$ sp circ$C. At 15$ sp circ$C, toxin was produced faster when pork was initially packaged with O$ sb2$ or low levels of CO$ sb2$ (15-30%) as compared to 100% N$ sb2$. Higher levels of CO$ sb2$ (45-75%) delayed toxin production. In most treatments, spoilage preceded toxigenesis. Models were developed relating the above factors to the time until toxin production and to the probability of toxigenesis. Temperature, initial O$ sb2$ and irradiation were all significant factors.

The motivation of the research presented in this thesis was to investigate the potential of using a commercial 2.3 kW heat pump dehumidifier (HPD) simultaneously as a dryer for high-moisture agricultural products and for other domestic dehumidification/heating applications. A drying system incorporating the HPD was designed and constructed, along with instrumentation to gather data on the properties of process air as well as real-time weight of the material being dried. The HPD was equipped with an external water-cooled condenser that rejected excess heat out of the system. The design of the system allowed for conducting drying with recirculation of air as well as use of electrical heaters. In an open mode, the drying could be carried out simultaneously with room dehumidification and water heating in the secondary condenser. / The drying experiments were conducted with apple, tomato and agar gels. The system was found to be more effective in drying of material with higher amount of free moisture such as tomato. Comparisons were made between HPD assisted drying (partial and complete) and hot air drying (at 45°C and 65°C) in the same system using apple as the test material. Colour changes (L*a*b* values) in the samples were compared between treatments. It was observed that the degree of undesirable colour change was least in case of the HPD assisted system. The HPD dried fruit exhibited better rehydration properties than the hot air dried samples. Water activity of the HPD dried samples was noticeably lower than that of the hot air dried samples at the same water content, indicating that the residual moisture was probably held under higher tension. Histological observation indicated that there was a lesser degree of damage to the cellular structure of apple when dried with the HPD than when dried with hot air alone. / In terms of energy consumption, the process of HPD assisted drying is more expensive. Much of the energy input is rejected at the secondary condenser as excess heat. Unless this heat is recovered for another purpose, or the system is modified to reuse it for drying, the drying process must carry this loss entirely. The specific moisture extraction rate (SMER) for apple was as low as 0.1 kg per kWh with the HPD assisted system. The SMER values for drying at 45°C was 0.5 kg per kWh and was almost 0.8 kg per kWh at 65°C. / The HPD assisted drying system demonstrated the ability of heat pumps to link different energy related activities viz., drying, space dehumidification and water heating. The energy expenditure is expected to be impressive when considered for all the related applications. The concept of utilizing heat pumps on farms to link up different energy streams for better utilization of the low-grade heat sources is discussed. A possible drying efficiency assessment in the form of energy-based evaluation is proposed.

The application of visible/near-infrared hyper-spectral analysis to monitor the quality of frying oil and fried breaded chicken nuggets was investigated. / Partial least squares (PLS) calibration models were developed to predict the acid value, total polar components and viscosity of heated oils with different ratios of hydrogenation. Coefficient of determination (R2) and root mean square error (RMSE) were calculated to assess the performance of each model. Results of the study demonstrated good prediction ability of the calibration models for the quality parameters with R2 values of over 0.92. / The second study was based on developing calibration models for prediction of moisture and fat contents of fried breaded chicken nuggets with different levels of moisture and fat contents. Performing the same procedure for evaluation of the PLS calibration models, results of the study demonstrated that moisture and fat contents of fried breaded chicken nuggets could be predicted with R2 values of 0.92.

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No description available.