Minimally processed fruits and vegetables are increasingly demanded by local consumers and for export purposes. However, the marketing potential of these produce is limited because of physiological ageing, biochemical changes and microbiological spoilage that lead to a short shelf life. The use of polymeric packaging films to control microbial and metabolic processes and edible coatings to control the white blush formation respectively, have shown potential in improving the quality of minimally processed carrots. In combination they may form a double barrier to gases and water vapour that could provide an interaction effect to enhance the shelf life of minimally processed carrots. The aim of the study was to determine the effects of the polymeric packaging films of different permeability and edible coatings at different levels of concentration, alone and in combination on the physiological and biochemical, microbiological, and sensory quality of minimally processed carrots. A factorial experiment of 3 polymeric packaging films x 3 levels of edible coating was conducted. The three polymeric packaging films were P-Plus®, an oriented polypropylene which were fully permeable to gases and water vapour (pi, control), semi permeable (p160) and least permeable (p90) to gases only. The semi permeable and least permeable packaging had similar water vapour permeability. The coating was Nature Seal®, a cellulose based, at 0% (control), 7.5% and 15% w/w. Carrots were minimally processed into slices, dipped in the edible coating, then packed in the polymeric films and stored for 12 days at 10°C. Four packs were analysed for each combination treatment on d4, d8 and d12, and dO was taken as reference point. With time, the head space in the semi permeable packaging (p160) showed a decrease to about 11.5-13.6% oxygen and an increase to about 7.5-9.6% carbon dioxide. The least permeable pack (p90) showed an oxygen decrease to about 9.8-7.6% and a carbon dioxide increase to about 12.3-13.5%. This change showed the creation of a modified atmosphere that will decrease the metabolic activities. As the coating concentration increased, a slight increase in carbon dioxide and a slight decrease in oxygen were recorded in the head space of the packs. This change was unexpected as the coating was supposed to be a gas barrier. Thus, this change questioned the gas permeability properties of the edible coating. The polymeric packaging and the coating interacted to give lower oxygen and higher carbon dioxide levels in the head space atmosphere. However, packaging had a more pronounced effect in the creation of the modified atmospheres than the coating. A lower white blush formation and a higher retention of chroma values was recorded on the lower surfaces of the carrot slices than on the upper surfaces (upper surfaces refer to those that were facing the packaging material, the lower surfaces was the opposite side of the upper surfaces). This showed that the relative humidity gradient was probably not the same between the surfaces. The coating effectively controlled the white discolouration and maintained higher chroma values on both surfaces of the carrot discs, but packaging did not affect the colour changes of the upper surfaces. An interaction effect was also observed between the packaging and coating showing a better control of the white blush formation of the lower surfaces of the carrot discs. Yeast and moulds did not prove to be a problem in minimally processed carrots as they were lower than 103 cfu/g carrots throughout the storage period. When the carrots were visibly spoiled, the lactic acid bacteria were over 106 cfu/g and the psychrotrophs were about 107 to 108 cfu/g. Initially, a high growth rate of psychrotrophic bacteria occurred followed by a high growth rate of the lactic acid bacteria. This showed a dynamic relationship between the two microbes. Visible rot was observed by brown discolouration, tissue softening and exudate production. The packaging controlled the microbiological growth and spoilage as compared with the coating that enhanced it. A decrease in pH from d4 to d12 corresponded to an increase in the lactic acid bacteria and visible spoilage. Combination of edible coatings and polymeric packaging films did not show any synergistic or additive effects to enhance the shelf life of minimally processed carrots despite some interactions between these two variables. This was because the polymeric packaging films primarily prevented microbiological growth and spoilage, whereas edible coatings partly controlled white blush formation. White blush formation was the most important shelf life determinant of minimally processed carrots. Research efforts should therefore be focused on overcoming this defect. / Dissertation (MSc (Food Science))--University of Pretoria, 2007. / Food Science / unrestricted

This research examines an edible and medicinal plant species, Balsamorhiza sagittata Pursh (Nutt) (balsamroot, or spring sunflower). Included are: 1) a study of literature concerning previous uses and potential agronomic applications of B. sagittata; 2) an ecological study to assess the general habitat requirements of B. sagittata at three populations in the Northwestern Plateau of British Columbia; and 3) an agronomic study of B. sagittata, the main purpose of which is to explore the development of the species in a cropping system or as a horticulture plant. Ethnobotanical literature confirms that B. sagittata has a long tradition as a highly significant food and medicinal resource on the Northern plateau. A review of botanical and range literature indicates that the species is an ecologically important forb in sagebrush ecosystems. Ecological data collectci:l was significantly different between the field sites. The only variable that was statistically similar at the Pavilion Mountain, Hat Creek Valley and Botanie Valley research locations was the number of blooms on the B. sagittata plants. Furthermore the data did not indicate significant correlations to explain variation in the number of B. sagittata plants between sample plots. Preliminary agronomic experiments indicate that B. sagittata can be propagated by seed, both in a greenhouse and at a field location. Treating seeds with ethylene before stratification significantly increased seed germination. / Graduate

Human subsistence within the Cape Floristic Region (Cape) dates back to our inception as a distinct species. Unique archaeological evidence found here for the defining attribute of cognitive modernity, as well as coinciding paleo-climatic challenges to survival, both highlight the Cape’s potential to support the existence of pre-historic hunter-gatherers. This habitat, with its unprecedented diversity of geophytes and other plant growth forms, has not yet revealed its potential to provide carbohydrate resources for early Homo sapiens sapiens. In order to investigate this potential, an ethnobotanical survey of the south Cape coastal area near Still Bay was conducted. Despite 17th Century colonialism marking the onset of indigenous plant knowledge decline, the 18 people of Khoe-San descent interviewed in this survey still actively used 58 indigenous edible plant species with a variety of 69 uses. Fruit showed the highest popularity of plants used (52 percent) followed by nectar, with plants having underground storage organs (USOs) ranking third (34 percent). Among growth forms, shrubs dominated (34 percent) followed by geophytes and trees (both 21 percent). With the exception of Prionium serratum, which was rare in the research area, this study failed to identify species that could have formed a staple source of carbohydrate for pre-colonial Khoe-San peoples of the Cape south coast. While eight species of USOs were identified (12 percent of total) only Cyphia species emerged as an important carbohydrate source. This study indicated the importance of Thicket Biome species as a source of edible plants. The second component of the study comprised a two year phenological survey of indigenous edible plant species in four primary vegetation types. A total of 32 USO species and 21 species with aboveground edible carbohydrates (fruiting species) were identified across all sites. Limestone Fynbos had the richest flora of edible species (21 USO species and 18 fruiting species), followed by Strandveld (15 USOs and 13 fruiting species), Renosterveld (8 and 8, respectively) and lastly Sand Fynbos (5 and 5, respectively). The season of highest apparency showed slight variation amongst the four sites over the two years, with more variation evident in the period of apparency. The first survey year had below average rainfall, while the second year received an average rainfall amount. The second year saw a dramatic increase in apparency of abundance for all sites (50 to 60 percent increase) except for the Sand Fynbos site, which showed little change. The other sites showed a one month increase in the period of apparency in the second survey year. Overall, late summer to autumn was the period of lowest apparency of USOs. The ripening of certain fruiting species during this time would have provided a source of carbohydrate when USO availability was at its lowest. Strandveld had the highest biomass in the peak of apparency (over 80 kgha-1) in the first year with a nearly 20 percent increase for the second year. The combined biomass for the four study sites in the first survey year was roughly 150 kgha-1 and 185 kgha-1 for the second year. The apparency of abundance (ripe and edible phase) of fruiting species did not increase much for Renosterveld and Strandveld in the second survey year, except for Limestone Fynbos (49 percent increase) and Sand Fynbos (53 percent). A multivariate analysis showed seven phenophases for high apparency of edible USOs and ripe fruit across the four vegetation types. Given the contribution of evergreen USOs and fruiting species, there would always have been carbohydrates available for foragers to collect in the major vegetation types of the south Cape coast. However, harvesting and processing this carbohydrate resource would have posed cognitive challenges for MSA hunter-gatherers, given the interwoven taxonomic complexity of numerous toxic plant species, and the diverse phenology of edible plant species within the varied vegetation types. These challenges were undoubtedly mastered, highlighting the Cape environment as a possible catalyst to improved human cognitive maturity.

This study used cross-sectional survey data to estimate farmers` perceptions of, and commonly cultivated ILVs, factors that influence the participation of smallholder famers in the production of Indigenous Leafy Vegetables and its contribution to household food security]. With regard to farmers` perceptions of ILVs, descriptive results reveal that a majority of the people from the study area share positive perceptions with respect to ILVs. Regression estimates for determinants of participation indicate that the production of ILVs is primarily conditioned by shared perceptions and institutional factors rather than the socio-economic attributes of farmers. Public policies that address the institutional framework (extension, credit, market and social networks) in favour of ILVs are more likely to promote production. Also, more research on the documentation and benefits of ILVs, supported by investments targeting educational campaigns towards promoting positive attitudes and dispelling fears and myths surrounding ILVs, will further promote production. With reference to the contribution of ILVs to food security, descriptive results indicate that participation in the production of ILVs leads to a higher HDDS and a lower HFIAS. Regression estimates further revealed that participation positively contributes to a higher HDDS and a lower HFIAS, suggesting that households who participate in the production of ILVs are more likely to be food secure than non-participants. Therefore, participation in the production of ILVs has significant potential to address household food security.

Edible insects have been part of the diet of many countries across the world for several decades. It is becoming increasingly popular in the europian developed countries, mainly because of the content of nutritionally important substances. The theoretical part of the thesis deals with the characterization of edible insects in terms of nutritional benefits, explains the reasons and method of breeding edible insects. For the analysis of nutritionally active substances, flour of house cricket (Acheta domesticus) was used. A. domesticus belongs to the representatives of insects legalized from 1.1. 2018 on the EU market. Of the significantly nutritional substances, proteins, lipids, fatty acids, fiber and selected minerals were analyzed. In this study, optimalization of vertical electrophoresis SDS-PAGE was performed to determine protein fragment sizes. In the second part the influence of acricket flour addition protein bars was investigated by sensory analysis. In the experimental part that was found that cricket flour contains protein, lipids and fatty acids in significant amounts. It also contains important minerals for human health such as magnesium, potassium, iron or zinc. However, the sensory properties of protein bars for consumers were not very attractive.

This research examined a single bulb-bearing edible plant species, yellow glacier lily (Erythronium grandiflorum ). Three main approaches to the research were taken: 1) an ecological study, to determine the general habitat requirements of the species in western Canada, and to investigate the nature of vegetative reproduction in the species; 2) an ethnobotanical study, consisting of an extensive literature search for all recorded First Nations' uses of the species (in Canada and elsewhere), in addition to interviews with contemporary Interior Salish elders; 3) a nutritional study, examining in detail the nutritional characteristics of the bulbs, and particularly changes in the carbohydrate content over the course of the growing season and with different types of treatments. The ecological data indicate that E. grandiflorum is more abundant in meadow environments or sites with deciduous cover than in sites with coniferous forest cover. Flowering plants tended to be more abundant and robust at low elevation meadows, while seedlings and juveniles were disproportionately represented at high elevation meadows. Decreased juvenile success in the low-elevation meadows may be related to relatively high litter from shrubs and grasses. Experimental data indicate that appendages on the bulbs, which persist as remnants of previous years' bulbs, can act as vegetative propagules if mechanically separated. In addition, both bulbs and appendages were successfully transplanted over a two-year period from a subalpine meadow to a very different habitat type, 1500 m lower in elevation. The ethnobotanical review confirms that the species was traditionally a highly significant root resource for northern plateau peoples, particularly the Secwepemc and Nlaka'pamux peoples, for probably thou.sands of years. These peoples collected, stored, and traded large quantities of the bulbs, and the traditional processing strategies generally included drying and pit-cooking. People developed a detailed ecological understanding of the species, and practiced active resource management strategies. Nutritional results indicated a carbohydrate-rich food resource, with the main storage carbohydrate consisting of starch (not inulin or other fructan) through most of the growing season. There are significant quantities of sugars (including fructo-oligosaccharides) present at the beginning of the growing season, but starch increases rapidly and peaks (along with overall food value) in the early (green) fruit stage of growth. For bulbs at the fruiting stage, drying markedly increases sugars in the bulbs relative to starch, while pit-cooking the dried bulbs does not have significant effects on relative amounts of carbohydrates. However, pit-cooking has important qualitative effects on the appearance, taste, and possibly storage properties of the bulbs, as well as representing an efficient processing strategy. I argue that traditional harvesting and management strategies practiced by First Nations people (including tilling, thinning, replanting of appendages, and landscape burning) mean that the ecology and ethnobotany of the species cannot be considered in isolation. Based on previous ecological and ethnoecological work on this and similar species, it seems likely that yellow glacier lily is adapted to a periodic, moderate disturbance regime, which traditional practices may have mimicked or enhanced. / Graduate

Thesis(M.Sc.(Agriculture Horticulture)) -- University of Limpopo, 2019 / Innovative methods of preserving the quality of traditionally processed green leafy vegetables are underway in Africa. Improvement of processing and preservation methods of leafy vegetables is another way of overcoming perishability restrictions and guaranteeing continued quality food supply in rural areas. The objectives of this study were: to determine the effect of time-based oven-drying on (1) mineral composition, (2) proximate composition and (3) microbial profiling of cowpea (Vigna unguiculata). Separate experiments were conducted for raw and cooked cowpea leaves with four treatments, viz 0 (sun dried), 24, 48 and 72 hours of oven-drying, arranged in a randomised complete block design with 5 replications. In raw cowpea leaves, relative to control (sun-drying), oven-drying period 48hrs, significantly decreased Potassium (K), Manganese (Mn), and Sodium (Na) content in raw cowpea leaves by 6, 9 and 13%, respectively. Similarly, oven-drying period 72hrs significantly decreased Ca, Fe, Mg, Zn, P and S by 5, 11, 16, 18 and 57%, respectively. In cooked cowpea leaves, relative to control (sun-drying), oven-drying period 24hrs significantly increased Na by 18%. Similarly 48hrs oven-drying periods increased Fe and K by 6 and 8%, respectively. Similarly, oven-drying period 72hrs significantly increased Ca, Mg and Mn by 8, 8 and 3%, respectively. In contrast, oven-drying period 72hrs significantly reduced Zn, P and S by 16, 10 and 39%, respectively. Relative to control (sun-drying), oven-drying period 24hrs significantly increased fat by 46% in raw cowpea leaves, however oven-drying period 72hrs significantly decreased protein, moisture, ash, fibre and carbohydrate by 10, 29, 18, 0.5, and 7% respectively. In contrast, relative to control (sun-drying), 72hrs increased energy by 3%. In cooked cowpea leaves, relative to control (sun-drying), ovendrying period 24hrs significantly increased energy by 1%. In contrast, relative to control (sun-drying) 72hrs oven-drying period decreased energy by 1%. Similarly, oven-drying 72hrs significantly decreased protein, moisture, ash, fat, fibre and carbohydrate by 8, 14, 13, 19, 0.4 and 10% respectively. Relative to control (sun-drying), oven-drying periods 24hrs significantly increased Staphylococcus spp. in raw cowpea leaves by 6%, respectively. Relative to control (sun-drying) 72hrs oven-drying period significantly decreased Shigella spp. by 92%, respectively. In cooked leaves, relative to control (sundrying), 72hrs drying periods decreased both Shigella spp. and Staphylococcus spp. by 99 and 21%, respectively. Total coliforms unit of Salmonella spp, Escherichia coli, Pseudomonas spp, and Bacillus cereus were absent and/or at an undetectable level according to the Tempo Biomerieux system results. In conclusion, cooked leaves retained most essential mineral elements as compared to raw when subjected to 72hrs of ovendrying as there was an improvement in the concentration of Ca, Fe, K, Mg, Mn and Na. However, in both raw and cooked cowpea leaves proximate composition was negatively affected as there was a decrease in protein content. Oven-drying period of 24 hours can be used to minimize the loss of protein. Cooked cowpea leaves subjected to 72hrs of oven-drying had least total coliforms for both Shigella spp and Staphylococcus spp, therefore have potential to serve as an alternative to sun-drying to reduce microorganism causing spoilage in leafy vegetables. Drying raw cowpea leaves under oven-drying periods less than 72 hours should be avoided as it reduces the mineral concentration and increase microbial count of microorganisms responsible for spoilage / National Research Foundation (NRF)

For many years, substitutes for butterfat have been the subject of much controversy. Their acceptance as being nutritionally equal to butterfat has often been question. The importance of this problem lies primarily in its economic and nutritional significance. A recent study of pulic attitudes toward dairy products conducted by Alfred Politz Research, Inc. for the American Dairy Association, shows that 48.4 per cent of the poulation believed that butter is a more nutritions food than oleomargarine. Only 6 per cent thought that oleomargarine is more nutritious while 27.2 per cent believed they are about the same. The remainder, 18.4 per cent, stated that they did not know. Margarine tax laws were in force for some time while vegetable oils were being tested as a human food. In addition to chemical examination, many investigations were conducted with rats, calves, and humans. Although there were still conflicting results, the tax laws were repealed and substitutes wen on the market to compete with butter. Many investigators still question the decision that substitutes are qual to butter, nutritionwise. Many investigations (4, 6, 21, 34) have shown that butter contains one or more growth factors which have not, as yet been identified. Chemical methods have failed to identify any of these factors, and so other methods have been considered. It is a well known fact that interrelationships exist between fat metabolism and the metabolism of other substances. It has been shown (11) that dietary fat affects the metabolism of other nutrients such as calcium and phosphorus. Although not clearly understood, it has been demonstrated (25, 37) that the kidney plays an important role in fat transport and metabolism. The value of urinalysis as a method of indicating the metabolism as a whole is well known, as well as is the high sensitivity of metabolic systems to minute quantities of some substances. The possibility of detecting growth factors or other substances through a study of excreted metabolites seems worthy of consideration in this study. Recent work with paper chromatography at the University of Texas (48) has indicated that each individual has a specific urinary metabolic pattern. Similarities have been found in the patterns of identical twins and schizophrenics. It was also found that the diet changed this pattern to a certain extent, although this was not studied extensively. The problem reported here is a study of urine obtained from highly inbred rats fed animal and vegetable fats analyzed by use of paper chromatography.

Indiana University-Purdue University Indianapolis (IUPUI) / Cannabis (and its main psychoactive component, THC) is one of the most widely-used drugs in the world, and recent expansion of its legal status has made it available in a variety of formulations and at a potency unrivaled in history. While its medicinal properties are gaining scientific support, so too is its potential to lead to abuse and dependence. Both initiation of cannabis use and frequent cannabis use are most prevalent in adolescence, and compared to adults, cannabis use by adolescents is associated with a greater likelihood of developing cannabis dependence and cannabis use disorder. Given the ethical limitations surrounding research that provides cannabis to non-users or non-adults, animal models of drug use can be valuable tools for the study of causes and consequences related to drug use, as well as allowing for investigating brain mechanisms underlying these factors. However, only recently have models in which animals reliably use cannabis (THC) at levels above its respective vehicle and at levels which produce consistent behavioral and physiological effects become available, and in no case has age-related differences in this use been examined. Thus, one goal of the current study was to directly compare the self-administration of edible THC (a route of administration used by humans and a formulation increasing in popularity) between adolescent and adult mice. Adolescents also appear to be differentially sensitive to various effects of several classes of drugs, and they have been shown to be less sensitive to the aversive effects of cannabis, thereby putting them at greater risk for elevated and continued use. Evidence also suggests that, in addition to the risk associated with adolescent cannabis use, having initial positive subjective experiences resulting from its use is a strong predictor of subsequent cannabis dependence. Thus, the second goal of the current study was to use the place conditioning paradigm to examine the reward- (or aversion-) inducing properties of THC in adolescent and adult C57BL/6J mice, using both the traditional experimenter-administered THC (via injection) as well as edible THC self-administration. Prior to initiating these THC studies, sensitivity of the place conditioning procedure to age-related differences in drug-induced reward was validated using cocaine, yielding locomotor stimulation in both ages and a decreased sensitivity to cocaine’s rewarding properties in adolescent mice. When provided limited access to edible THC dough in doses ranging from 0.0 to 6.0 mg/kg, mice showed a dose-dependent reduction in consumption across access sessions, and this reduction was more rapid in adult mice at the highest doses, suggesting that adolescent mice might have been less sensitive to its aversive properties. These same mice, as well as a separate group of mice receiving injection (also 0.0 to 6.0 mg/kg THC), were given place conditioning sessions, alternating between THC dough and control dough or THC injection and vehicle injection, for 6 days per week and were tested once per week across a total of 3 weeks. Mice conditioned using edible THC showed a neutral response (neither reward nor aversion) at all doses. However, mice conditioned using injected THC showed a conditioned place aversion to the highest dose, which was more pronounced in adult mice. Interestingly, in mice self-administering edible THC, the dose of THC consumed was related to the outcome of place conditioning, such that a conditioned place preference was observed for adult mice which shifted their consumption of 3.0 mg/kg edible THC downward relative to those mice with full consumption of 3.0 mg/kg, and for adolescent mice which had the highest degree of consumption of 6.0 mg/kg edible THC relative to those mice with the lowest consumption of 6.0 mg/kg. Furthermore, initial place preference outcomes at the individual level at test 1 predicted subsequent doses of edible THC consumed, suggesting mice adjust their self-administration of edible THC based on the subjective experience it produces. Besides its impact in place conditioning, THC also had differential effects on body weight and locomotor activity based on age and route of administration. Collectively, this project demonstrates that adolescent mice are less sensitive to the hedonic properties of both cocaine and THC, and that differences in edible THC self-administration between ages, and between individuals within an age, are likely related the subjective experience of its rewarding and aversive properties.

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