<OL> <LI> Develop reduced salt fermentation procedures for cucumbers and cabbage that will consistently produce vegetables with firm texture and appropriate flavor;<LI>Preserve non-fermented cucumbers and peppers in acidified, low-salt, or salt-free solutions so they can be stored and used as process-ready ingredients for food products; <LI>Develop processing technologies to convert sweetpotatoes into shelf-stable ingredients, such as puree and dehydrated powder, with physical, chemical, and sensory properties suitable for use as ingredients in restructured and formulated food products; <LI>Increase nutrients and beneficial phytochemicals in sweetpotato products by selection of cultivars with increased concentrations of target components and by optimization of processing conditions to minimize losses. </OL> Additional funds in support of project plan objectives 1,2,5: (1) to determine the metabolic changes that lead to the death of vegetable fermentation bacteria in response to acid and to develop approaches to assure growth of desirable fermentative organisms; (2) to understand and prevent degradation of the cell wall structure that results in softening of fermented and acidified vegetabes stored in low salt without thermal treatments.
APPROACH: New or improved processing methods will be developed for cucumbers, cabbage, peppers and sweetpotatoes that will increase utilization of these vegetables. Research will be done both to solve problems that limit utilization and to create opportunities to broaden uses for these vegetables as ingredients in formulated foods. Problems to be addressed include excessive generation of processing wastes, loss of quality attributes, and inadequate commercial shelf-life. Opportunities include development of new convenient-to-use ingredient forms for these vegetables and enhancement of the nutrient and beneficial phytochemical levels in products produced from these vegetables. Control of texture is a major quality issue that must be addressed in the development of improved processing methods. Therefore, the basic mechanisms which accelerate and inhibit softening of cucumbers, peppers, and cabbage will be investigated, as well as the factors that modify the rheology of sweetpotato puree. A recent development by this unit of an experimental technique to experimentally separate the effects of hydrogen ions from the effects of protonated acids on killing bacteria will be exploited to further our understanding of the physiology of acid tolerance in fermentative bacteria.