195 research outputs found
Methods of rapid bruise assessment and the formulation of robust bruise indices for potatoes
When potato tubers are subjected to impacts, the sub-surface tissue may become discoloured as damaged cells produce the blue-black pigment melanin. Bruising caused during harvesting and handling can lead to downgrading of potatoes for the processing industry and quality retail trade. The two aims of this thesis were to reduce the time to detect bruising, and to develop a non-subjective method for the quantification of bruising.Reflectance spectrophotometry was investigated as a rapid, non-subjective and non- invasive way of detecting bruising. Wavelengths from ultraviolet to near infrared were selected by discriminant analysis to separate unbruised and bruised tubers. Neural nets were trained with these wavelengths to identify bruised tubers in a sample of unbruised and bruised tubers. The detection of bruising gave inconsistent results in unpeeled tubers, but proved to be reliable in peeled tubers.The rate of bruise development at air pressures up to 10 bar was measured by reflectance spectrophotometry and by a visual rating. The production of dopachrome, an orange pre-cursor pigment of melanin, was used as an early indication of bruising. Dopachrome is visible to the human eye and the time for bruise detection can be reduced to approximately 3 hours when compressed air is used.Infrared and microwave thermography were used to measure possible rises in bruised tissue temperature. Thermography was used in conjunction with scanning laser Doppler imaging to detect changes in the biological zero of bruised tissue. No significant differences could be detected between unbruised and bruised tubers using these techniques.Reflectance spectrophotometry was also used in combination with a colour digital camera to automatically measure bruise area in peeled tubers. While the camera alone could measure bruise area with precision, constant adjustments were needed. Reflectance spectrophotometry was faster but less precise than the camera for measuring bruise area.A new bruise index was formulated by taking measurements of the volume of a tuber removed per peeler stroke for the variety Record, and using the data to model the percentage volume lost for any variety. By counting the number of peeler strokes to remove a bruise an estimate of the tuber volume lost could be derived. This method can accommodate any type and size of bruise and results in an index that can be easily interpreted
Potato sprout suppressants with particular reference to tecnazene
Abstract available p. ii-i
Response in growth performance, blood metabolites, nutrient digestibility, digesta characteristics and carcass characteristics of Windsnyer pigs fed increasing levels of potato hash silage.
Doctor of Philosophy in Animal and Poultry Science. University of KwaZulu-Natal, Pietermaritzburg, 2017.Abstract available in PDF file
Mattrygghet i Europa: en kartlegging av kritiske matpraksiser og kulturelle forskjeller i Frankrike, Norge, Portugal, Romania og Storbritannia
How is food handled in safe and unsafe ways from retail to fork in European households? This is the overall research question raised in this report. The aim of this report is to contribute to an in-depth, detailed, empirical and nuanced analysis of how food is handled in everyday life in five European countries: France, Norway, Portugal, Romania and the UK. The first chapters (Part 1) describe the food cultural difference and food safety variation between the five countries, theories of practices that underpin the study and the transdisciplinary methods employed for studying shopping, transportation, storage and cooking a meal with chicken and raw vegetables in 75 European households. The first empirical chapters (Part 2) introduce the households in this study (chapter 2.1), discuss the everyday food life the households (chapter 2.2) and describe food anxieties and experiences with foodborne illnesses (chapter 2.3). Part 3 concentrates on food procuring and organising practices in the households and includes three empirical discussions of shopping (chapter 3.1), transportation (chapter 3.2) and storage (chapter 3.3). Part 4 discusses food preparation and comprises five chapters discussing the order of cooking (chapter 4.1), chicken preparation (chapter 4.2), vegetable preparation (chapter 4.3), determining doneness (chapter 4.4) and washing hands (chapter 4.5). Finally, Part 5 discusses the main findings in the report and suggests further research steps.info:eu-repo/semantics/publishedVersio
Tropical root crops : root crops and the African food crisis; proceedings of the Third Triennial Symposium of the International Society for Tropical Root Crops - Africa Branch, held in Owerri, Nigeria 17-23 Aug. 1986
Meeting: International Society for Tropical Root Crops - African Branch, Triennial Symposium, 17-23 Aug. 1986, N
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A study of contextual factors influencing the perception of vegetables among primary school children
Low vegetable consumption among children, particularly in Scotland, is a cause for concern. Many factors may influence children’s vegetable consumption, including contextual factors such as socio-economic status and city of residence. It is also likely that associated sensory properties influence children’s perceptions of vegetables. The research presented in this thesis aimed to examine the influence of city of residence and socio-economic status on the vegetable perceptions and preferences ofprimary school children. The impact of the children’s frequency of vegetable consumption on their perceptions and preferences was also investigated. In total, 23 children aged between 8- 11-years-oldparticipated in the pilot study, and 94 children aged between 8-10-years-old in the main study. The samples used in the main study (baked beans, tomatoes, carrots, cabbage, cauliflower, turnip, sweetcom and peas) were all commonly consumed in Scotland and familiar to the subjects. Repertory grid method was used to obtain perceptual information of a free-choice nature relating to the vegetables, and additional hedonic data (without sample tasting) and contextual information was collected from each child. Data were principally analysed using generalised Procrustes analysis and internal preference mapping. Non-linear principal components analysis (PRINCALS) and homogeneity analysis (HOMALS) were employed to explore associations between children’s perceptions of the vegetables and demographic variables. Finally, consensus data were obtained from the free-choice data and an extended internal preference map was constructed to examine correlations between perceptions and preferences for the vegetables. In conclusion, the children’s preferences for and perceptions of the vegetables were influenced by socio-economic status, probably related to their experiences with/exposure to vegetables due to differences in the availability of different varieties between the socially disparate areas. Neither age, city of residence, gender, nor typical weekly consumption of vegetables were found to significantly influence the children’s preferences or perceptions of the sample vegetables. The texture of the vegetables strongly influenced the children’s perceptions and preferences of the sample vegetables. Despite the apparent influence of the samples ’ textural attributes, the flavour of the vegetables (i.e. sweet versus bitter) was additionally responsible for sample likes/dislikes. Repertory grid was found to be a suitable method for children aged 8- years-old and above. It was also determined during the course of this thesis that children aged 8-years-old and older could successfully understand the concept of linear bipolar scales and could rank samples accordingly, both for their liking of the samples andfor the intensity of particular descriptive attributes using such scales
Social science perspectives on managing agricultural technology
TechnologyAgricultural researchResource managementFarmer participationEvaluation
Social science perspectives on managing agricultural technology
Experiences of 15 social science research fellows who recount their roles in particular research projects at the International Agricultural Research Centers they were appointed. In addition to highlighting the contributions social scientists can make in the field of agricultural research, their papers offer a candid look at the kinds of work in which the Centers currently are engaged.Technology, Agricultural research, Resource management, Farmer participation, Evaluation, Farm Management, Research Methods/ Statistical Methods,
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