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"Theobroma cacao" beans are an economically significant commodity for the Fiji Islands. The cocoa beans are harvested in the wild and then fermented and sun-dried under tropical weather conditions. The high relative humidity (RH) as well as the unpredictable weather conditions extend the sun-drying time and causes quality issues in the final dried product. Maintaining product quality is important as export quality cocoa beans are sold at premium prices to chocolate manufacturers internationally. The problems in sun-dying can be solved by reducing the RH of drying air stream. This is possible with desiccant wheel technology (DWT). The solid desiccant material in DWT desorbs moisture from air and reduces humidity. The desiccant material can be regeneration between 60 and 100 °C for the next cycle. This temperature conditions can be achieved by using a solar dryer. This study tested the drying conditions below 20% RH on small batches (6 kg) of fermented Fijian cocoa beans at 45 °C and 55 °C. Impact of these conditions on the drying kinetics and bioactive quality was tested. Experimental data was used to validate a mechanistic drying model. The model was developed using partial differential equations (PDEs) with an implicit scheme for a targeted drying time of 72 hours. Finite difference method (FDM) was used to solve PDEs. The model output was comparable to experimental data from drying runs in Fiji. Reducing the RH at 45 °C showed a better retention of key bioactive compounds, such as polyphenols, caffeine, and theobromine when compared to other treatments. These findings are presented in detail in this thesis and suggests that DWT can provide consistent drying conditions in a tropical environment. The drying model is a useful tool for predicting the drying conditions for cocoa beans based on multiple input variables. The model can be used to advise cocoa farmers on the estimated processing time for cocoa beans to meet the demands of the export market.

Bone loss, common in women after menopause, is characterized by reduced bone mineral density with disruption of bone microarchitecture, leading to higher fracture risk and osteoporosis. There are few treatments, and most have adverse side effects. Intervention studies have shown protective effects of lycopene against bone loss in animal models. Lycopene is a lipid-soluble carotenoid found mainly in tomatoes. The molecule exists in all-trans- and a variety of cis- configurations; and cis- lycopene isomers have been reported to be more bioavailable than all-trans-. ‘Moonglow’, an orange heirloom tomato, contains >90% of its lycopene in cis- isomeric form and thus may be a better source of naturally bioavailable lycopene than red tomato, which contains all-trans- lycopene. We hypothesised that consumption of moderate daily doses of whole ‘Moonglow’ tomato would reduce bone loss more effectively than red tomato in rat and cell models of osteoporosis. In vivo, ‘Moonglow’ tomato supplementation delivered physiologically relevant plasma lycopene concentrations within four days of feeding. The post-ovariectomy rat model was successful in accelerating bone loss. ‘Moonglow’ tomatoes delivered a higher plasma lycopene concentration than red tomatoes and were beneficial in reducing a bone turnover marker compared to red tomatoes, even when fed after initiation of bone loss, but did not improve bone mineral density. Ovariectomy reduced gut bacteria abundance; compared to red, ‘Moonglow’ tomato feeding restored the numbers of Lactobacillus, Enterococcus, Bacteroides and E. coli. In vitro cell culture studies showed that both red and ‘Moonglow’ tomato hexane extracts induced a significant decrease in the number of bone-resorbing TRAP-positive osteoclasts at 10 µmol/L lycopene concentration. In conclusion, there were slight differences in bone measurements between red or 'Moonglow' tomato feeding, except for the significant reduction of one bone turnover marker. This suggests that

Export of feijoa (Acca sellowiana [O.Berg.] Burret) to the main markets in Europe, Asia and North America is currently by airfreight that is not only expensive but rather unsustainable as the industry expands. With the ongoing breeding works and expansions of plantings, growers will eventually have to seek for an economic mode of transport. As is the case with kiwifruit, apples, avocadoes, and squash, seafreight will provide an alternative option that is both cheaper and accommodates large fruit volumes. The short storage life of feijoa, however, is likely to pose a challenge to seafreight (that requires at least 6 weeks of storage) if appropriate postharvest techniques are not identified to extend storage life. Feijoa stores for about 4 weeks at 4 °C after which it becomes overripe, loses flavour, and develops chilling injury and internal browning. This study was undertaken to examine potential postharvest techniques that could extend storage life and maintain quality of feijoa. The postharvest techniques investigated were temperature and relative humidity management, harvest timing, step down conditioning, intermittent warming, chlorophyll fluorescence and development of non-destructive grading tools. The varieties used in this study were ‘Kakariki’, ‘Wiki Tu’ and ‘Triumph’ that were stored for 8 weeks under various conditions. To assess the effects of temperature and relative humidity in storage, ‘Kakariki’, ‘Wiki Tu’ and ‘Triumph’ were stored at 1 °C (85% RH) and 4 °C (88% RH). These conditions were set to result in equal water vapour pressure deficits at both temperatures. The effects of RH on feijoa quality during 8 weeks storage were tested by using a polyethylene liner (polyliner) to cover the fruit in each tray, for half of the treatments. Despite good retention of some attributes indicating quality (firmness and skin colour) for up to 8 weeks at 1 °C, many fruit developed chilling injury making it unsaleable and therefore causing huge losses. At both 4 °C