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Item Identification of mechanical parameters to be used as a firmness standard on quality evaluations of stored blueberry : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Manawatu, New Zealand(Massey University, 2022) Rivera Smith, SebastianBlueberry firmness is considered a relevant quality variable influencing consumer acceptability of fresh blueberries. However, the blueberry supply chain and research community have not yet adopted a standard method to measure firmness on postharvest quality evaluations. This thesis has focused on characterising the mechanical properties of blueberry ‘Nui’ and ‘Rahi’ as influenced by different factors such as storage relative humidity (i.e., fruit water loss), controlled atmosphere and harvest maturity. The mechanical parameters were obtained by using the instrumental methods of texture profile analysis (TPA) equipped with a flat plate and the penetration test equipped with a 0.39 mm round tip diameter needle probe. Mechanical parameters of hardness slope (BHS, also known as chord stiffness) of TPA and displacement at skin break (DSk) of the penetration test can be used to track water loss changes in stored blueberries. The DSk and BHS can also accurately detect quality changes induced by controlled atmosphere storage. In addition, BHS can detect maturity differences in stored blueberries, but the force at skin break (FSk) provides better detection of maturity differences at harvest evaluations. To demonstrate the relevance of chord stiffness evaluations at a commercial level, sensory evaluation of texture of hand-touch firmness using a formal sensory panel setting and trained assessors was related to instrumental mechanical parameters. Chord stiffness measured as BHS using a flat plate compression and skin break slope (SSk) measured using a needle probe were strongly related to consumer sensory perception of hand-touch firmness. A blueberry batch with an average BHS ≤0.47 kN m⁻¹ or SSk ≤0.13 kN m⁻¹ was associated with a very high likelihood of unmarketable berries (i.e., berries are ‘soft’ or ‘very soft’). In summary, BHS was an informative parameter of blueberry quality across factors inducing the textural changes and providing commercially relevant information about consumer acceptability. These results can assist the development of a standard instrumental method to measure postharvest firmness on blueberry quality evaluations for research and commercial purposes. Further studies should focus on validating the feasibility of BHS to determine blueberry quality across other sources of textural variation, such as calcium and ethylene-related treatments. In addition, threshold values for mechanical parameters related to consumer acceptance (sensory analysis) may be identified across an extensive range of blueberry genotypes and using other sensory descriptors also relevant to the consumers, such as crispness. Finally, this research identifies alternative areas for further studies, such as the blueberry firming (an increase of firmness during storage) occurring consistently on blueberries ‘Nui’ stored under high RH in regular air or a controlled atmosphere of 5 kPa CO₂ + 4 kPa O₂.Item A Scholarly Review of Supply Chain Integration within the New Zealand Blueberry Industry(School of Food and Advanced Technology, Massey University, Manawatu Campus, Palmerston North, 2020-12) Bezuidenhout, Carel N.; Martin, Mitchel R.; Williams, Alexander H.; Peiris, Avinash; Wood, Katherine I.A.; Zhang, Tianxin; Shea, Gabriella; Lavelua, T. David; Cosgrove, Megan J.N.; Forman, Jade S.; Paranjape, Mrunal; Kodikara, D.R. Thenuka; Dalglish, Perry; Weng, Lihong; Cosson, Isaac; Raza, Shakeela; Claydon, Jonathon E.D.; Kour, Harpreet; Kathara, Rahul Dilip; Carel N. Bezuidenhout, PhDEthics and credence attributes are the humanistic basis for establishing sustainable supply chain development. It determines brand reputation, ecology and customer experience. Furthermore, good ethics and credence Attributes promote the progress of industry leadership and increase the possibility of win-win strategies, especially in terms of negotiation. Negotiation is the premise of supply chain collaboration. The purpose of collaboration is to establish a synchronized supply chain to improve the ability of industry coordination. This is also the key to creating value, and the importance of risk management cannot be ignored. It is not only a guarantee for the smooth operation of the supply chain, but also an important measure to improve the flexibility of the supply chain. Finally, the results of supply chain integration need to rely on performance metrics and benchmarking to control and improve the overall performance of the supply chain. This publication evaluates modern theories in all these areas and contextualise it to the New Zealand blueberry industry. It is important that the reader appreciates the scholarly origin of this publication.Item Identification of blueberry leaf rust pathogen and quantification of disease infection levels in a blueberry plantation in Hastings, NZ : a thesis presented in partial fulfilment of the requirements for the degree of Master of AgriScience in Horticulture at Massey University, Turitea Campus, Palmerston North, New Zealand(Massey University, 2019) Chen, XiaoyingBlueberries (Vaccinium spp.) are a favourite fruit and they are produced worldwide. In New Zealand, blueberries are the main export berry fruit and contribute greatly to export income. More than 2,800 tonnes of blueberries were produced in the 2017/2018 harvesting season and earned $34.8 million export income in 2018. Currently, 740 ha of the blueberry plantations can be found in both the South Island and North Island. Otautau is the main growing region in the South Island while Waihopo, the Waikato regions of Ngatea and Ohaupo, the Bay of Plenty and Hastings are the regions in the North Island, producing most of the fresh blueberries in New Zealand. However, blueberry leaf rust has become a prevalent disease in blueberry production and a concerning issue for blueberry growers. In Hastings production sites, serious infections have been found in recent years. Although fungicides were applied to control blueberry leaf rust, this form of control is incomplete and unsustainable for blueberry production. The deployment of varieties that are naturally resistant would be a better option for managing blueberry leaf rust disease. Currently, few cultivars are available for this purpose, but breeding for rust resistance can address this demand. The main issues preventing the production of resistant varieties are insufficient knowledge about this rust pathogen in New Zealand, and the lack of resistant germplasm sources and efficient resistance screening procedures. In this study, using the morphological characteristics and genome sequencing results based on the Internal Transcribed Spacer (ITS) regions, Thekospora minima was identified as the causal organism of blueberry leaf rust disease in Hastings, Hawke’s Bay, New Zealand. Additionally, a field assessment was used for understanding the blueberry rust disease resistance levels in current blueberry cultivars. The disease incidence and disease severity of 23 blueberry cultivars, including five rabbiteye, three northern highbush and fifteen southern highbush, were assessed using Fiji software during the 2019 harvesting season. Based on a Tukey Honest Significant Differences (TukeyHSD) analysis, these observed blueberry cultivars were divided into four infection levels of blueberry leaf rust using the percentage of the infected area on the leaf (PIAL). ‘Scintilla’ was highly susceptible to blueberry leaf rust disease, while ‘Blue Moon’ and ‘Southern Splendour’ were moderately susceptible. Nineteen blueberry cultivars, made up of ‘Rahi’, ‘Centra Blue’, ‘Centurion’, ‘Titan’, ‘Sky Blue’, ‘Nui’, ‘Duke’, ‘Camellia’, ‘Misty’, ‘Springhigh’, ‘Snowchaser’, ‘Miss Jackie’, ‘Miss Lily’, ‘Georgia Dawn’, ‘Suziblue’, ‘Kestrel’, ‘Flicker’, ‘Sweetcrisp’ and ‘Palmetto’, showed susceptibility to this rust disease, and ‘‘O’ Neal’ was the one that showed partial resistance to the blueberry rust infection. Furthermore, using 1.5×104 concentration inoculum, an inoculation test was completed in a temperature-controlled room at the Plant Growth Unit of Massey University. The inoculum was sprayed on the healthy leaves from detached branches of the ‘Sky Blue’ blueberry cultivar and they were grown in reverse osmosis water for a 35-day observation on rust symptom development. Fiji software was applied in the assessment of disease severity in this inoculation test. A strong correlation (>0.99) was found between the increase in lesion area (ILA) from the inoculation test and the PIAL from field assessment. A preliminary prediction equation was established by a simple linear regression model. This equation can be used to predict the blueberry leaf rust level on different blueberry cultivars and breeding materials under field conditions by using the results from an inoculation test. This model would be an efficient approach for assisting the screening on blueberry leaf rust of blueberries.Item Characterising texture and cellular level responses of 'Centurion' blueberries during storage in different weight loss conditions : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Albany, New Zealand(Massey University, 2019) Franklin, Deena KelseyPostharvest blueberry softening hinders consumer acceptance and correlates with high moisture loss during storage. Such textural variations have been attributed to factors such as turgor, cell wall modifications and other microstructural changes in the outer cell layers of the fruit. This thesis investigated the impact of moisture loss on blueberry quality, as well as the structure/function relationships associated with fruit texture characteristics during postharvest using an integrated physical and microstructural approach. Four different weight loss conditions (62%, 76%, 93% and 98% RH) were evaluated over a three week postharvest storage period to assess blueberry texture parameters using a texture analyser, where microstructural changes were assessed by light microscopy and optical coherence tomography (OCT). Under high weight loss conditions there was an increase in berry softening and a decrease in texture characteristics whereas an increase in berry firmness, hardness and gumminess was observed during storage under low weight loss conditions. Light microscopy clearly illustrated microstructural differences among ‘Centurion’ blueberries stored in different weight loss conditions, in retention of cell shape, degree of cell to cell wall contact, the amount of space between cells and cell wall integrity. When berries lost moisture during storage, epidermal and subepidermal cells retained their integrity, and parenchyma cells lost integrity leading to collapse which may contribute to overall fruit quality during postharvest. 3D OCT images showed no obvious differentiation between large cells at each weight loss treatment, however significant differences were observed in the microstructure between each storage period. In general the microstructure of medium to large cells in the parenchyma tissue showed an increase in average surface area and total surface area after each storage period. In summary, low weight loss storage conditions help to preserve blueberry texture and quality, whilst maintaining cellular structure and integrity during postharvest storage. It is recommended blueberries are stored between 95 – 99% RH and at a low temperatures to prevent moisture loss during postharvest.Item Phytochemical variation during blueberry juice processing : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University, New Zealand(Massey University, 2015) Kasim, KhairulBlueberry is regarded as a ‘super fruit’ by many consumers and believed to offer health benefits for humans. It is well known for its high antioxidant levels and for the diversity of its anthocyanins. Blueberries can be eaten fresh but are very perishable, so are commonly kept frozen and available all year round. Frozen blueberries are suitable for a range of products including juice. During juicing, there are likely to be changes in phytochemical constituents arising from the various processing steps. These changes lead to variable composition of the finished juice and uncertain impacts on the ‘health value’ of the product. Therefore, this study focused on evaluating three major phytochemicals (anthocyanins, chlorogenic acid (CGA), and procyanidin B2) throughout juice processing in order to model compositional change. Blueberry juice processing involves a series of unit operations: thawing, blanching, mincing, enzyme treatment, separation of juice from pomace, pasteurisation, and bottling. Enzymatic degradation occurs during thawing of blueberries as they still contain ‘live’ oxidases. Prolonged thawing at warm temperatures would therefore be particularly bad for phytochemical degradation. If these oxidases are destroyed by blanching, thermal degradation also occurs but was found to be less aggressive than polyphenoloxidase (PPO) activity. Blanching at high temperature (= 70 °C) for 3 min eliminated PPO and significantly increased the phytochemical concentration in the juice but it induced pectin gel formation which reduced juice recovery. Depectinisation is essential after berry blanching to dissolve pectin gel and to avoid juice volume penalty. Significant losses of phytochemicals were also observed during pressing of the berries into juice, due to physical associations between the phytochemicals and the berry matrix, and entrapment. Blanching at 90 °C for 3 min followed by pectinase enzyme treatment at 50 °C for 2 h was the best way to deliver high phytochemical concentration in the juice with high juice volume recovery and acceptable viscosity. There is a risk that juices with high phytochemical concentration will seem bitter or astringent. This was found not to be the case in sensory trials, with consumers consistently preferring the high-phytochemical juices; it seems sugars in the juice masked any adverse perceptions. Because of the complexity of blueberry juice processing, the processing model developed in this study was simplified into three components: a defrost model, a recovery model and a thermal model. In short, the defrost model was used for the whole berry phase during thawing when PPO was still active; the recovery model accounted for losses into the pomace; and the thermal model covered the subsequent liquid phase. These processing models were able to predict anthocyanin and CGA changes throughout processing (particularly in blanched products) but procyanidin B2 behaviour was not predictable. This modelling approach provides the ability to predict variations in composition arising from changes in the juicing process and offers manufacturers the opportunity to produce consistent blueberry juice with a high phytochemical concentration.Item Influence of temperature management deficiences during postharvest on the quality of sea exported blueberries : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Horticultural Science at Massey University, Palmerston North, New Zealand(Massey University, 2012) Paniagua Gonzalez, Andres CristobalAfter harvest, fresh blueberries deteriorate rapidly due to fungal decay and softening. Postharvest softening is a major problem for the export industry, although the mechanisms for this softening are not completely understood. In order maintain product quality during the postharvest chain, blueberries need to be rapidly stored at the optimal temperature (0°C) and relative humidity (RH) (90-95%). However, rapid cooling is inhibited by the requirement of packing the product at an intermediary temperature (10 °C). Subsequently during marine export, blueberries are often shipped in reefer containers which are set up at the optimal temperature. Nevertheless, it is not known whether temperature heterogeneity within containers (4°C around the set point) constitutes an important factor affecting quality at the market place. Controlled atmosphere (CA) (8-15% CO2 combined with O2 > 1%) is also used in sea exported blueberries as a complementary technology to delay pathogen development, although is not clear what O2 concentration range delivers the best quality benefits. This thesis investigated the impact of cooling delays and temperature heterogeneity during shipping on the final quality of sea exported highbush and rabbiteye blueberries, as well as the interactions of these factors with CA. In addition, the influence of moisture loss on blueberry softening was investigated as a way to improve the current understanding of this quality defect. Cooling delays of 12 and 24 h at 10°C, simulating the packing process, were found to impact the quality of blueberries after a subsequent storage period of 6 weeks at 0°C. A delay of at least 12 h considerably increased the total moisture loss of blueberries over 6 weeks storage. However, the incidence of rotten fruit over the period of coolstorage was not affected by delays in cooling at 10°C. Considering that decay is the main factor limiting blueberry postharvest life, this result may place less relevance on accelerating the packing process despite its effect on fruit moisture loss. A laboratory recreation of temperature heterogeneity of 4°C around the set point, as reported for reefer containers, was shown to affect the quality of blueberries by the end of a coolstorage period. Compared to optimal storage conditions, commercially packed blueberries subjected to 4°C considerably increased (up to 20 fold) the incidence of rots after 6 weeks storage. Furthermore, this variability of 4°C led to slightly increased moisture loss from blueberries during simulated shipping. This result suggests that environments used during shipping of blueberries should minimise temperature variations below 4°C in order to improve blueberry quality. A flow-through system was utilised to simulate 3 different storage atmospheres (2.5% O2 + 10% CO2, 20% O2 + 10% CO2 and air) and assess the effect on blueberry quality during 6 weeks of storage, confirming that CA comprising increased CO2 concentration provides a clear effect in reducing blueberry decay incidence during storage. In addition, CA was found to slightly improve firmness retention during storage, although this benefit was not large enough to suggest a commercial impact. Moreover, increased O2 concentrations were able to alleviate the high CO2-induced softening during storage. The effect of CA on decreasing rot incidence was attributed to the influence of CO2 on pathogen growth, with no benefits achieved by reducing O2 concentration. This indicates that the export industry may benefit from improved quality outcomes and lower CA operational costs if O2 is maintained around 20% and CO2 increased within recommended ranges. The gas composition of storage atmosphere influenced the impact of temperature variability within shipping containers on blueberry quality. Controlled atmosphere comprising 10% CO2 in combination 2.5 or 20% O2 substantially reduced by up to 50% the effect of temperature on blueberry rot incidence during storage. In contrast, atmosphere composition did not alter the effects of cooling delays on blueberry quality. Therefore, CA seems to provide a valuable protection against temperature deficiencies that occur during marine export. Finally, an independent experiment was conducted to test the existence of a causal relationship between moisture loss and postharvest firmness for blueberries. Storage conditions were controlled so only the extent of moisture loss varied between treatments. Opposing firmness outcomes were obtained under different weight loss ranges, in addition to a high correlation between both parameters. Furthermore, different water loss patterns for firming and softening were suggested as observed in MRI analysis. This result provides evidence that fruit moisture loss plays a major role in determining firmness responses of blueberries.Item Phytochemical optimisation of blueberry juice: a research report presented in partial fulfilment of the requirements for the degree of Master of Engineering in Food Technology, Massey University, Turitea campus, Palmerston North, New Zealand(Massey University, 2011) Birt, NatashaBlueberries contain a high concentration and diversity of anthocyanins which are responsible for the blue/purple pigment of their skin. Like many other fruits and vegetables they also contain a large amount of chlorogenic acid (CGA) within the fruit flesh and seeds. Together these phytochemicals appear to account for most of the high antioxidant activity of the fruit, although within the scientific community a consensus has not been reached as to their effects on human health. Fresh blueberries have a limited season and are perishable unless stored frozen. Processing of blueberries into juice allows year round sale, and importantly less market-driven pricing. Therefore the aim of this research project was to investigate and optimise factors which may be significant in producing a high phytochemical blueberry juice. The pigment of blueberries is concentrated in the skin, and therefore smaller blueberries have the highest anthocyanin concentrations on a weight basis. Consequently the three highest concentrations were found in cultivars ‘Elliot’, ‘Burlington’ and ‘Duke’. Conversely chlorogenic acid is not restricted to the blueberry skin; ‘Elliot’, ‘Bluecrop’ and ‘Burlington’ had the three highest concentrations, while ‘Duke’ had the lowest. The profile of individual anthocyanins was also found to be diverse amongst cultivars. Therefore if individual anthocyanin(s) are shown to be important for specific health conditions further consideration should be given to cultivar selection. Upon review of the current blueberry juice manufacturing process, large anthocyanin losses were seen at three key steps: after thawing of the fruit, removal of the press cake and holding of the juice between pressing and pasteurisation. Two alternative processes were compared where a slightly higher anthocyanin concentration was achieved for ‘hot press juice’ but a lower chlorogenic acid concentration than the alternative ‘cold press’ juice. Modifications to the manufacturing process were investigated using the pilot plant at Massey University. It was found that blanching of frozen blueberries before pressing was successful in significantly increasing the anthocyanin and chlorogenic acid concentration of the juice (about a 5 fold increase of anthocyanins and a 4 fold increase in chlorogenic acid from previous levels). However, this did alter the sensory properties of the juice significantly, with a more cooked flavour and thicker texture. Other variations that were trialled, such as milling, ii variation in holding time and temperature between pressing and pasteurising, had comparatively little effect on the anthocyanin and chlorogenic acid concentration. Storage tests on blueberry juice showed a clear relationship between the storage temperature and anthocyanin retention, where warmer temperatures resulted in larger anthocyanin degradation. At the end of the six month storage period, juice storage at 5°C gave 63% anthocyanin retention while juice storage at 25°C gave only 8% retention. Some protection was also afforded to juice packed in glass bottles rather than plastic and stored in the dark rather than the light; but this difference was far smaller than the effect of temperature. Chlorogenic acid levels appeared to be comparatively less affected; only relatively small amounts of degradation were observed. It is important to note that when the antioxidant capacity was measured for stored juice at six months under the various treatments, there was only a small degree of degradation for all samples as compared with at time zero. Previously researchers had encountered a similar phenomenon and suggested that unknown anthocyanin degradation products may still be able to contribute to the juice’s antioxidant capacity. However, here it is also suggested that chlorogenic acid may have had a more significant contribution to the antioxidant capacity that it is usually credited with, due to the large amount present with relatively little degradation throughout the storage period. This information may be used to produce and market a juice with high anthocyanin, chlorogenic acid and/or antioxidant properties. Of the health effects evaluated here, currently, research in cardiovascular disease and neuroprotection effects are looking the most promising with regard to dietary blueberry supplementation in humans, although there is still a lack of double blind randomised placebo controlled studies to come to any consensus within the scientific community. Additionally, at the present time, the use of health claims on food products in New Zealand is being revised (Food Standards Authority proposal P293). As the current state of nutrition research surrounding plant polyphenols is inconclusive it may be important to use generic statements such as ‘high in antioxidants’ rather than statements about specific compounds.