Philip E. Nelson

Finite element analysis of temperature distribution in microwaved cylindrical potato tissue

Abstract A new finite element formulation for the analysis of temperature distribution in a microwaved potato cylinder was developed by deriving and incorporating a non-linear heat generation term for an axisymmetric and transient heat transfer problem. Using the dielectric properties of potato, temperature distribution was predicted well for the center temperatures lower than 80°C. The deviation between the predicted and experimental temperatures beyond 80°C was corrected using the dielectric properties of water. Pronounced heating was found along the longitudinal axis passing through the center point of the potato cylinder.

An in vitro method for estimating biologically available vitamin B6 in processed foods.

1. An in vitro method which used enzymic digestion of the food matrix to release biologically available vitamin B6 is described. 2. Vitamin B6-fortified liquid model foods were thermally processed. After these foods had been freeze-dried, one part was subjected to enzymic hydrolysis at pH 2.0 with pepsin (EC 3.4.23.1) followed by a hydrolysis at pH 8.0 with pancreatin. The vitamins that were found in the supernatant fraction, after an acidified methanol treatment of the hydrolysate, were estimated by high-performance liquid chromatography (HPLC). The other part was given to rats who were kept on a vitamin B6-depleted diet. 3. The biologically available vitamin B6 content of the processed model foods, as determined by rat bioassay, showed good correlation with the vitamin B6 determined by HPLC. 4. It has proved possible to use this in vitro, two-stage enzymic digestion system followed by HPLC determination to determine biologically available vitamin B6 in vitamin B6-fortified processed model foods.

Processing of nutritious, safe and acceptable foods from CELSS candidate crops

A controlled ecological life-support system (CELSS) is required to sustain life for long-duration space missions. The challenge is preparing a wide variety of tasty, familiar, and nutritious foods from CELSS candidate crops under space environmental conditions. Conventional food processing technologies will have to be modified to adapt to the space environment. Extrusion is one of the processes being examined as a means of converting raw plant biomass into familiar foods. A nutrition-improved pasta has been developed using cowpea as a replacement for a portion of the durum semolina. A freeze-drying system that simulates the space conditions has also been developed. Other technologies that would fulfill the requirements of a CELSS will also be addressed.

From Tomato King to World Food Prize Laureate

This autobiographical article describes my early years, education, and career at Purdue University. Helping form and expand the Department of Food Science at Purdue was exciting and gratifying, and working with students in the classroom and on research projects was rewarding and kept me feeling young. My research on bulk aseptic processing allowed me to help solve problems relevant to the tomato industry, but I learned later that it had much broader relevance. I certainly never expected the impact and visibility of the work to result in my being awarded the World Food Prize. Being the first food scientist to win this award has enabled me to focus increased attention on the need to reduce food losses.

Earth benefits of interdisciplinary CELSS-related research by the NSCORT in Bioregenerative Life Support.

Earth benefits of research from the NSCORT in Bioregenerative Life Support will include the following: development of active control mechanisms for light, CO2, and temperature to maximize photosynthesis of crop plants during important phases of crop development; automation of crop culture systems; creation of novel culture systems for optimum productivity; creation of value-added crops with superior nutritional, yield, and waste-process characteristics; environmental control of food and toxicant composition of crops; new process technologies and novel food products for safe, nutritious, palatable vegetarian diets; creation of menus for healthful vegetarian diets with psychological acceptability; enzymatic procedures to degrade recalcitrant crop residues occurring in municipal waste; control-system strategies to ensure sustainabilty of a CELSS that will enable management of diverse complex systems on Earth.