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Item Using non-destructive laser backscattering imaging technology for kiwifruit quality assessment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatū, New Zealand(Massey University, 2024) Yang, ZhuoKiwifruit is one of the most important exported horticultural products in New Zealand. The supply of kiwifruit to both national and international markets can be extended by harvesting kiwifruit unripe and storing with proper postharvest practice. During kiwifruit storage, quality monitoring is required for inventory planning and consistent quality maintenance. Currently, the industry is using sampled data to represent a batch of kiwifruit. However, kiwifruit quality is difficult to estimate based on destructively measured samples due to the heterogeneous population quality distribution. Therefore, a non-destructive technology is preferred allowing quality measurement for all kiwifruit prior to and during storage, as well as before exporting and marketing. Commercial spectral-optical devices, such as near-infrared (NIR) spectroscopy, have been employed by the industry for fruit grading and sorting at harvest, and have achieved good performance in total soluble solid content (SSC) and dry matter content (DMC) estimation. However, NIR spectroscopy had a poorer performance in estimating kiwifruit flesh firmness (FF), the primary quality indicator. During light and fruit tissue interaction, those optical devices capture data containing primarily the absorption signal related to kiwifruit’s chemical composition. Therefore, the FF estimation is indirect and the accuracy of FF measurement is affected when both textural structures and SSC change during postharvest ripening. Laser backscattering imaging (LBI) records the backscattered signal after a single laser beam interacts with kiwifruit tissue. These light-tissue interactions include light absorption and scattering. The back-scattered signal could be analysed as an attenuation profile, and this attenuation profile is determined by optical properties of absorption (μa) and reduced scattering (μs’) coefficients, which correlate with fruit chemical compositions and physical properties, respectively. Therefore, LBI data is potentially helpful for FF estimation and early-stage internal disorder symptoms detection. This PhD work developed a non-destructive approach based on the LBI technique to segregate kiwifruit with internal disorders [brown marmorated stink bug (BMSB) feeding injury and chilling injury (CI)], as well as soft fruit at FF threshold of 9.8 N. Estimation of μa and μs’ was achieved with 56.6 % and 91.5 % accuracy respectively, using a pre-classification method and validated against optical phantoms of known optical properties. Additionally, LBI parameters directly extracted from the images were utilised to develop segregation models owing to the uncertainties in μa and μs’ estimation. For internal disorder detection, using the estimated kiwifruit μa and μs’, the segregation accuracy for kiwifruit with BMSB damage was 84 % and 62 % for ‘Zesy002’ (n=198) and ‘Hayward’ (n=198). Using extracted kiwifruit LBI parameters, the segregation accuracy for kiwifruit with CI was 92 % and 39 % for ‘Zesy002’ (n=396) and ‘Hayward’ (n=400). In addition, ‘Zesy002’ (n=30) and ‘Hayward’ (n=30) LBI during the postharvest ripening for kiwifruit were collected through a 15-day shelf life at 20 °C, where extracted LBI parameters were used to develop a time-series model. Absolute values of kiwifruit LBI parameters increased during the kiwifruit ripening process for both cultivars and the trend of LBI parameters may be correlated with kiwifruit softening. For segregating kiwifruit based on FF, the kiwifruit FF segregation model was calibrated, cross-validated and externally tested using kiwifruit LBI and corresponding FF data collected from 2 seasons with varying at-harvest maturity stages and stored at 2 temperatures. The segregation model accuracy for classifying fruit based on the 9.8 N FF threshold was 75 % and 70 % for ‘Zesy002’ (n=2247) and ‘Hayward’ (n=3558) in test sets. In conclusion, this work confirms that LBI technology has the potential for segregating soft kiwifruit or kiwifruit with early internal disorder symptoms and be adapted to the packhouse sorting system. However, in this work, FF segregation uncertainty at the 9.8 N threshold was observed when ‘Zesy002’ FF (N) ∈ (5,15) and ‘Hayward’ FF (N) ∈ (5,20) due to LBI parameter overlapping. Improved image analysis and segregation algorithms need to be investigated to enhance the segregation sensitivity for kiwifruit FF in the lower firmness range.Item Mathematical modelling of airflow during forced draft precooling operations : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2024-11-01) Tapia Zapata, Nicolas IgnacioBy the year 2020, the kiwifruit industry represents approximately 37 % of the horticultural export industry sector in New Zealand. Thereof, the kiwifruit cold chain aim is to reduce losses due to poor temperature control and energy usage during refrigeration. By forced convection aided by fans in palletised kiwifruit, field heat is removed rapidly prior to storage, thus optimising shelflife of the produce. Previous Computer Fluid Dynamics (CFD) model determined the optimal operating point for palletised kiwifruit during forced-draft cooling. However, CFD requires complex simulation, in detriment to computational efficiency and solving time. Therefore, there is an imperative to provide innovative tools that optimise package design by iterating several designs and that is applicable to the local industry sector for cold chain optimisation. In this spirit, this projects aimed to development of a simplified approach for the prediction of airflow distribution of palletised kiwifruit during forced-draft cooling, that can be coupled with an alternative heat transfer model, thus providing a fast and robust package optimisation routine that can inform cooling performance of several package design and pallet configuration.Item Neurobiological impacts of kiwifruit consumption in a pig model and its effects on sleep and mood in young adults : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Sciences at Massey University, Palmerston North, New Zealand(Massey University, 2024) Kanon, Alexander PutraKiwifruit (KF) positively impacts gut health, specifically in alleviating gastrointestinal symptoms and improving laxation. Emerging evidence also suggests that consuming KF influences sleep and mood, with most studies indicating improvements in subjective measures of these attributes. Previous research has explored the mechanisms behind these effects using in vitro and rodent models, which have considerable differences to human physiology. This study explores the impact of New Zealand KF on various brain physiological aspects in animal models and humans. It explores the antioxidant neuroprotective potential of KF, examines alterations in the gut microbiome composition and bioamine concentrations, analyses temporal bioamine concentration effects in plasma and brain regions, and assesses the acute effects on human sleep quality and mood. Findings reveal that in one week, consumption of both green and gold KF reduced oxidative potential in plasma, increased concentrations of 5-Hydroxyindoleacetic Acid (5HIAA, a serotonin metabolite), and induced changes in the abundance of specific microbial genera along the colon of adult pigs, a more representative model of human physiology. Furthermore, green KF enhances antioxidant protective potential in plasma and various brain regions, while gold KF elevates plasma vitamin C levels and tends to reduce acetylcholinesterase activity across the entire brain. Temporal effects highlight distinct patterns in metabolite concentrations between green and gold KF, with γ-Aminobutyric Acid (GABA) and serotonin exhibiting notable interactions in different brain regions. Good and poor sleepers consuming KF before sleep had improved sleep quality and mood. Fresh KF facilitates easier sleep onset for good sleepers, while freeze-dried KF leads to increased ease of awakening in the morning for poor sleepers. Notably, both forms of KF increase the urinary excretion of 5HIAA and reduce feelings of sleepiness while increasing alertness. The inclusion of the fruit skin appears to increase improvements in sleep quality, suggesting a more noticeable effect. These studies provide valuable insights into the neurobiological effects of KF and support its potential as a functional food to improve sleep in humans.Item Genomic architecture of resistance to latania scale (H. lataniae) in kiwifruit (A. chinensis var. chinensis)(BioMed Central Ltd, 2023-10-31) Flay C; Tahir J; Hilario E; Fraser L; Stannard K; Symonds V; Datson PBACKGROUND: Latania scale (Hemiberlesia lataniae Signoret) is an armoured scale insect known to cause damage to kiwifruit plants and fruit, which ultimately reduces crop values and creates post-harvest export and quarantine issues. Resistance to H. lataniae does exist in some commercial cultivars of kiwifruit. However, some of the commercial cultivars bred in New Zealand have not inherited alleles for resistance to H. lataniae carried by their parents. To elucidate the architecture of resistance in the parents and develop molecular markers to assist breeding, these experiments analysed the inheritance of resistance to H. lataniae from families related to commercial cultivars. RESULTS: The first experiment identified a 15.97 Mb genomic region of interest for resistance to H. lataniae in rtGBS data of 3.23 to 19.20 Mb on chromosome 10. A larger population was then QTL mapped, which confirmed the region of interest as the sole locus contributing to H. lataniae resistance. inDel markers mapping the region of low recombination under the QTL peak further narrowed the region associated with H. lataniae resistance to a 5.73 Mb region. CONCLUSIONS: The kiwifruit populations and genomic methods used in this study identify the same non-recombinant region of chromosome 10 which confers resistance of A. chinensis var. chinensis to H. lataniae. The markers developed to target the H. lataniae resistance loci will reduce the amount of costly and time-consuming phenotyping required for breeding H. lataniae scale resistance into new kiwifruit cultivars.Item Understanding kiwifruit postharvest physiology and quality changes in tropical retail market conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, New Zealand(Massey University, 2022) Malavalli Veeregowda, Praveen KumarKiwifruit is New Zealand’s major horticulture crop. A challenge that exists for the New Zealand kiwifruit industry in emerging tropical markets is maintaining fruit quality during marketing. In Asia and the Middle East, high ambient temperatures (> 30 °C) are often prevalent. The domination of traditional fruit marketing practices in these regions results in fruit exposure to these conditions. Understanding of fruit postharvest responses to high ambient temperatures is limited. In this thesis, a supply chain survey was conducted in India and Singapore, where kiwifruit at edible ripeness were found to be exposed to temperatures > 30 °C and ethylene concentrations as high as 150 nL L-1 during retail. Back in the laboratory, kiwifruit were exposed to simulated tropical conditions, where 12 h of exposure to 40 °C resulted in significant changes in fruit physiology as evidenced by rapid respiratory decline. The findings from this initial study indicated that 40 °C exposure may have a lethal impact on kiwifruit whilst 33 °C may not. The role of ethylene in influencing kiwifruit physiology under tropical conditions was investigated by treating kiwifruit with 1-MCP to prevent ethylene responses. Consequently, 1-MCP treated fruit exposed to 33 °C retained firmness both in the presence or absence of exogenous ethylene whilst untreated fruit softened rapidly, indicating that the possible ethylene exposure in tropical conditions advances kiwifruit softening. A further study aimed to identify exposure temperature and time combinations that trigger detrimental outcomes for kiwifruit including after a period returned to coolstorage. Like previous, kiwifruit at 40 °C exhibited rapid respiratory decline, while at 33-38 °C, no such response was evident. This confirmed that 40 °C exposure for 12 h could have a lethal impact on kiwifruit physiology. Fruit that were exposed to high temperatures (33-40 °C) beyond 24 h and later coolstored developed internal breakdown symptoms indicating that irrecoverable degradative processes are induced. A plausible mechanism as a result of heat exposure is the occurrence of anaerobic respiratory metabolism. At 33-40 °C, Respiratory Quotient (RQ) in kiwifruit remained ≥ 1 reaching 3 at 40 °C whilst at 20 °C, RQ remained close to 1. Contrastingly, ethanol accumulation increased at high temperatures but minimal ethanol content changes occurred at 20 °C. At some high temperatures, ethanol content increased with time but no symptoms of heat injury were evident, suggesting that heat injury may not be exclusively caused by the accumulation of anaerobic metabolites. The increase in ethanol content measured in kiwifruit at high temperatures indicates the potential risk of off-flavour development at retail conditions in tropical markets. Overall, this research contributes to kiwifruit quality maintenance in tropical markets by elucidating safe exposure durations for kiwifruit and identifying a postharvest treatment of 1-MCP as a potential quality maintenance tool. Future research requirements include identifying molecular mechanisms that control physiological changes in kiwifruit at high temperatures, identifying causes for the differential responses observed between ‘Hayward’ and ‘SunGold™’ and investigating the efficacy of 1-MCP at wider ranges of high temperature conditions.Item Aspects of fruit growth and rootstock/scion influence on field performance in kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Horticultural Science at Massey University(Massey University, 1994) Cruz, Castillo Juan GuillermoThe influence of nine Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. de!iciosa rootstocks and four 'Hayward' strains on the growth and cropping performance of kiwifruit vines four, five, and six years after grafting was determined. Multivariate analysis of variance on phenotypic data was an effective technique to distinguish main effects of rootstock and scion and the interactions between the two. Canonical Variate Analysis was particularly useful for distinguishing between root systems, 'Hayward' selections and their interaction on the basis of field performance. This statistical technique was highly effective in summarizing the complex relationships of the data and provided a useful method of reducing the dimensionality of the problem. A rootstock effect on plants topworked on root system 4 (male) was characterised by high field performance, as expressed by high floral bud burst and high yield of large size fruit in each of three seasons. Own rooted vines had the highest field performance in one season. Own rooted 'Hayward' B strain had a large trunk diameter and high yield in comparison to the other three own rooted 'Haywards', in two seasons. In contrast, when strain 'B' was topworked across eight root systems the vines produced a low yield of small fruit in two seasons. 'Hayward' A as a scion achieved the best field performance in yield and fruit sizing across eight root systems in two seasons. Root system and scion interactions were characterised by differences in 'Hayward' selection effects on individual root systems, and root system effects on individual 'Hayward' selections. In particular scion performance on root system 9 differed significantly, as did the effect of rootstock on the scion selection 'Hayward' D. Fruit from some vines had a significant increase in percentage of soluble solids and fruit firmness at harvest, and during storage. Scion effects on percentage of soluble solids present at harvest were lost after fifteen weeks of cold storage. Conversely, in some cases, significant interaction between rootstock and scions on that variate were found only after a period of fruit storage. Rapid fruit softening during storage occurred in some rootstock scion combinations, particularly 'Hayward' Con its own roots and three of the eight rootstocks. The effects of early summer partial defoliation on fruit size, return bloom, and carbohydrate content of 'Hayward' kiwifruit vines were studied. An arbitrary distinction was made between shoots arising from the 'replacement cane zone' (RCZ), the wide horizontal area between the T-bar support wires, and the fruiting zone (FZ), comprising all growth arising outside the T-bar support wires. A 75 % defoliation of new shoots in the RCZ significantly reduced mean fruit size 13 and 7 g, in the RCZ and FZ, respectively, and starch content of the shoots as determined in March. The treatments did not significantly alter the root starch content over several dates sampled. The return bloom of the vines was significantly reduced by 50 and 75 % defoliation. Pre-anthesis factors and early fruit growth were important in determining final fruit size. Ovaries from early opening flowers had significantly greater fresh weight than late ovaries. Cell number and cell size in the inner and outer pericarp of the ovary at anthesis were similar for early and late opening flowers but core cell number was significantly higher for ovaries from early flowers. At commercial harvest, the cell number in the outer pericarp of fruit from early flowers was greater than fruit from late flowers. When treated with the synthetic cytokinin CPPU (N-(2-chloro-4-pyridil)-N-phenylurea), fruit from early flowers achieved a larger fruit size than fruit from late flowers. Fruit weight response to the synthetic cytokinin CPPU was enhanced when applied in combination with GA₃ (gibberellic acid) + 2,4-D (2,4-dichlorophenoxyacetic acid) in three seasons. In treated 'Hayward' fruit, the relative thickness of the outer pericarp was increased, and the inner pericarp decreased. Low and high seeded fruit treated with the hormone mixture had mean fresh weights of 102 and 136 g, respectively, compared with 47 and 90 g in untreated fruit. In kiwifruit inner pericarp cultured in vitro there was no callus growth in the absence of hormones, even when seed were present. A mix of 2,4-D + GA₃ + BAP (6-benzylaminopurine) stimulated callus growth. In the presence of 2,4-D + GA₃ , seeds or BAP increased fruit callus growth and reduced the phytotoxicity effect of abscisic acid (ABA). The uptake of ¹⁴C-CPPU and ¹⁴C-CPPU + 2,4-D + GA₃ by 'Hayward' kiwifruit, and the distribution of radioactive label in fruit tissues was examined. After 21 days the recovery of radioactivity was significantly greater from fruit treated with mixture compounds to CPPU alone. At commercial harvest radio-active metabolites of CPPU were on average 6.2 and 4.8 ppb (fresh weight basis) for soluble and insoluble acetone fractions, respectively. Of this activity, 90 % was present on the skin, and 10 % in the flesh.Item Effect of Kiwifruit actinidin on the digestion of gluten proteins : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Sciences at Massey University, Palmerston North, New Zealand(Massey University, 2022) Jayawardana, Isuri AchinthaGluten proteins are resistant to complete proteolysis by the human gastrointestinal tract (GIT) enzymes, due to their high proline- and glutamine-rich peptide sequences. Proline confers resistance to proteolysis by digestive enzymes, producing indigestible proline-rich peptides, some of which can trigger immunogenic reactions that are responsible for gluten-related health disorders such as coeliac disease, wheat allergy and gluten sensitivity. At present, gluten-free diets (GFD) are the only promising therapy for gluten-related health disorders. However, maintaining a lifelong GFD is challenging. As an alternative therapy, gluten-specific enzymes to hydrolyse immunogenic peptides have shown promising results. Most of these are of microbial origin. Identification of natural alternative enzymes is desirable, with fruit-borne enzymes a possible solution. Actinidin, a cysteine protease found in most green kiwifruit (Actinidia deliciosa), is suggested as an effective exogenous enzyme, to be utilized in this category. The objective of this PhD study was to evaluate the effect of actinidin on the digestion of gluten and gluten-derived immunogenic peptides in the GIT. The effectiveness of actinidin was tested using different in vitro GIT models and an animal (pig) preclinical model with purified gluten or whole wheat bread as sources of gluten, and purified actinidin or and fresh green kiwifruit as sources of actinidin. Analytical techniques such as free amino nitrogen determination, enzyme-linked immunosorbent assay and both targeted and untargeted mass spectrometry were used to determine the degree of hydrolysis (DH), R5 gluten epitopes and immunogenic peptides respectively. Actinidin hydrolysed peptide bonds adjacent to proline residues in the 33-mer peptide, one of the most immunogenic gluten peptides. The gastric DH of gluten proteins was influenced by an interaction between pH and actinidin concentration (P < 0.05). Actinidin at a concentration of > 2.7 U/mL and pH > 2 during hydrolysis was considered ideal for gluten hydrolysis. Actinidin increased (P < 0.05) the rate of acceleration of DH of gluten and reduced the amount of R5 epitopes present in the small intestine using a semi-dynamic in vitro GIT digestion model. Actinidin also accelerated the gastric hydrolysis of wheat proteins in whole wheat soda bread, which was reflected in a faster reduction of R5 epitopes in the gastric conditions and the rate of reduction (P < 0.05) of most of the immunogenic marker peptides present in the small intestine. In vivo, the presence of dietary actinidin in the form of green kiwifruit significantly (P < 0.01) enhanced the gastric digestion of wheat proteins in whole wheat soda bread fed to pigs as a model of human GIT digestion. The amount of R5 epitopes was lower (P < 0.01) in the stomach, proximal and distal small intestine and terminal ileum of pigs fed diets containing green kiwifruit (P <0 .05). The number of immunogenic peptides in the proximal small intestine was low in the pigs fed green kiwifruit diet compared to that of the pigs fed yellow kiwifruit diet (control). In addition, a diet containing green kiwifruit markedly reduced (P < 0.05) the amount of seven gluten immunogenic marker peptides including the 33-mer peptide in the stomach chyme of pigs. Actinidin was able to survive peptic proteolysis and gastric pH conditions until 300 min postprandial in pigs. Taken together, these results suggest that actinidin enhanced the rate of proteolysis of both purified gluten and gluten in a food matrix and reduced the amount of immunogenic gluten epitopes reaching the small intestine during GIT digestion in vitro and in vivo. Actinidin was able to reduce both the amount of and the time of exposure to immunogenic peptides in the small intestinal lumen, therefore it is a promising candidate to be considered in oral enzyme therapy for gluten-related health disorders.Item Effects of soil & foliar nutrient application strategies for improving fruit quality for 'Zesy002' kiwifruit : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Sciences at Massey University, Palmerston North, New Zealand(Massey University, 2021) Hashmatt, MaryaNutrient management research work has been conducted in established kiwifruit varieties such as ‘Hayward’ and ‘Hort16A’. But less is known about such research on the newly commercialised ‘Zesy002’ kiwifruit cultivar. A goal is to optimise sustainable production of quality fruits with high fruit dry matter percentage (FDM, a quality predictor at-harvest), without driving excessive vine vigour. The project is aimed to (i) increase calcium (Ca) nutrition and to (ii) optimise potassium (K) fertilisation to produce high quality ‘Zesy002’ kiwifruit at-harvest. The fundamental knowledge of the role of Ca and K nutrients and their interactions was used to increase the photosynthetic performance and improve at-harvest fruit quality. The study was based on the hypothesis that the competitive effect of high K supply on the uptake of Ca may be reduced at soil level by using (i) spatial and (ii) temporal separation of soil-applied Ca and K fertilisers, and (iii) foliar Ca applications after fruit set through to fruit maturity during the growing season. The study also tested the hypothesis that K application at different rates and growth stages through (i) soil-applied and (ii) foliar-applied fertilisation may better meet the nutrient demand of kiwifruit vines and developing fruit and therefore, may improve the potential of the fruit to compete for dry matter import. The results showed that both spatial and temporal separation of soil-applied Ca and K fertilisers reduced the competitive effect of high K input on the availability and uptake of Ca and therefore significantly increased leaf and fruit Ca concentration in ‘Zesy002’ vines compared to true control, not spatial and not temporal strategies and grower practice in each orchard. Likewise, foliar Ca significantly increased Ca concentration in leaf and fruit tissues in ‘Zesy002’ vines and significantly improved photosynthetic performance, nutrient uptake (vine physiology) and at-harvest fruit quality (fruit size and firmness). Both soil and foliar-applied nutrient strategies, which were used mainly to increase Ca nutrition, showed promising improvements in fruit quality; larger and firmer fruit with high soluble solids (SSC) and fruit dry matter concentration (FDM) at-harvest and after thirty-day storage. The results also showed that three split applications of soil K fertilisers (each 100 Kg K ha⁻¹) from bud-break (BB) through to 90 days after full bloom (DAFB) compared to one application either at BB, FB or 90 DAFB, improved at-harvest fruit quality in commercial orchards at Bay of Plenty and Hawke’s Bay, New Zealand. Foliar application of K fertilisers from fruit set through to harvest also improved vine physiology and at-harvest fruit quality. The optimisation of K by using both soil and foliar fertilisation strategies improved fruit growth rate during the growing season, at-harvest fruit weight, SSC and FDM compared to true control. The soil and foliar-applied nutrient (Ca and K) fertilisation strategies employed here were specifically targeted using ‘the right time’, ‘right amount’ and ‘right plant organ’ principles and successfully, delivered larger fruit with higher SSC and FDM at-harvest. For growers, this translates to a lower fruit count per tray (size class) and a higher taste Zespri grade, triggering increased premium payments and orchard gate returns. The fertiliser input used in foliar strategies was 3-8 Kg. ha⁻¹ and only a fraction of soil-applied fertilisation 50-300 Kg. ha⁻¹. Therefore, the foliar nutrient fertiliser application strategies employed in this study were inherently more sustainable approach compared to the soil-applied fertilisation. These research findings have significant implications in horticultural fruit crops to increase leaf chlorophyll, net photosynthesis and stomatal conductance, and increase leaf and fruit Ca and K concentration to deliver high quality fruit at-harvest. The research strategies used in this study can be very easily adapted to the existing fertilisation programs and applied in the commercial orchards. For example, fertiliser spreaders can be modified to side dress K to the weed-strip or broadcast K to alternate rows and broadcast Ca over the whole orchard floor to implement spatial separation of Ca and K fertilisers. Temporal separation of Ca and K can be very easily implemented by applying soil Ca fertiliser at BB and by delaying application of soil K fertiliser until closer to FB. Foliar Ca and K applications can also be easily included in the early season spray programs. For future research, there is a true potential to further maximise fruit quality gains by supplementing soil-applied fertilisation strategies with specific timely foliar applications.Item An integrated modelling approach to inform package design for optimal cooling of horticultural produce : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2018) Olatunji, Jamal RimkeitForced-air cooling is a widely used pre-cooling process that enables the New Zealand horticultural industry, valued at over NZD $8B in 2016, to maintain the quality of perishable exports. In the typical systems used in New Zealand’s horticultural industry, forced-air cooling involves stacking fruit boxes into pallets, which are stacked together in a refrigerated room, and a fan is used to create a pressure drop through the pallets. This forces cold air through the packaging ventilation and over the fruit, facilitating heat transfer and rapidly cooling the product from the field heat (~20 °C) to the storage temperature (0-2 °C), thus prolonging shelf life and preserving fruit quality. Package design is linked with cooling performance, as the specifics of the ventilation (i.e. placement and size of vents in the boxes) results in different airflow patterns. Unfortunately, it is not well understood how to predict the performance of a hypothetical design, which is partly why in industry and academia there has been a focus on package design testing – where through experimental or computational means, the performance of a given design is thoroughly tested. Trial-and-error experimental work represents a steep materials cost, and construction and validation of detailed mathematical models can be a highly arduous and specialised task. It would therefore be beneficial to the New Zealand horticulture industry and academia to have a suite of methodologies that can simply and rapidly predict performance of a hypothetical package design. It was proposed that such methods are based upon mathematical modelling, with a focus on flexibility, computational efficiency, and automation. The goal is that such a model can be used to rapidly develop mathematical descriptions of a wide variety of products and cooling scenarios, and if integrated with optimisation routines, will allow swift iteration toward an optimised design.--Shortened abstractItem Curing kiwifruit : physical, physiological and storage impacts : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Food Technology at Massey University, Auckland, New Zealand(Massey University, 2018) Doleh, LeilaCuring of ‘Hayward’ kiwifruit is a postharvest approach to reduce decay and maintain quality during long-term storage. Curing occurs immediately after harvest, with fruit placed in picking bins in a covered packhouse space for a few days. Curing contributes to fruit quality by allowing the picking scar to heal (resulting in reduced Botrytis rot) and allows a proportion of water loss, resulting in fruit cells that are less turgid and hence less prone to mechanical damage during packing. In the contemporary packhouse, curing is also used to buffer logistical challenges, since stockpiling fruit has advantages in ensuring the packing line continues to process fruit. In kiwifruit, the rates of cooling to storage temperature have previously been identified as an influence on long-term storage outcomes, including firmness and storage breakdown development (SBD). Little is known about how curing contributes to long-term storage, yet there is potential to impact post-storage fruit quality given that curing occurs immediately prior to packing and cooling. There is a lack of knowledge regarding the range of conditions which fruit are exposed to when bins are stacked under non-controlled conditions. It is also unknown how these conditions may influence fruit quality (i.e. fruit softening and SBD development) after long-term storage. This thesis incorporates monitoring of within bin environmental conditions to assess possible in-stack heterogeneity during curing.