Browsing by Author "East A"
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- ItemBlueberry firmness - A review of the textural and mechanical properties used in quality evaluations(Elsevier B.V, 2022-10-01) Rivera S; Giongo L; Cappai F; Kerckhoffs H; Sofkova-Bobcheva S; Hutchins D; East AFirmness is an important parameter for fresh blueberries as it influences the quality perceived by consumers and postharvest storage potential. However, the blueberry research community has not yet identified a universal standard method that can evaluate firmness for quality purposes. Different mechanical tests have been considered, offering different perspectives on this quality trait. This review summarises the most common methods previously used to evaluate textural and mechanical properties of fresh blueberries as influenced by pre- and postharvest factors. In addition, this review intends to assist the blueberry research community and commercial supply chain when selecting suitable methods to measure blueberry firmness as a fruit quality response. Different research initiatives to develop, optimize or standardise instrumental methods to assess blueberry firmness and relate to consumer sensory perception are reviewed. Mechanical parameters obtained by compression tests are the most previously used techniques to evaluate the influence of genotype, maturity, calcium, and postharvest management on blueberry firmness or to relate to sensory descriptors. However, standardising operational settings (e.g., compression distance, loading speed, and calculation procedures) is required to make results comparable across data collection conditions. Whether other mechanical test methods such as penetration or a combination of tests can better characterise blueberry quality or the relationship with consumer acceptance remains unknown and is worth studying.
- ItemData of texture profile analysis performed by different input settings on stored ‘Nui’ and ‘Rahi’ blueberries(Elsevier Inc, 2021-10) Rivera S; Kerckhoffs H; Sofkova-Bobcheva S; Hutchins D; East ATexture Profile Analysis is a well-established method for assessing mechanical properties of horticultural food products and consists of two compression cycles on a repeated motion to a given strain using a flat surface probe (i.e., compression plate). Input settings of target deformation (strain%) and duration (s) between compression cycles utilized for Texture Profile Analysis could influence output mechanical properties. The article provides data related to the ability of different Texture Profile Analysis operational settings to enable the separation of blueberries with variable mechanical properties. To create variable mechanical parameters of ‘Nui’ and ‘Rahi’ blueberries, fruit was stored in four relative humidity for 21 d at 4°C. For each storage humidity, mechanical properties of hardness (BH, N), hardness slope (BHS, kN m−1), apparent modulus of elasticity (E, MPa), and resilience (BR, -) were determined by utilizing two strain (15% or 30% of berry equatorial height). Meanwhile, mechanical parameters of cohesiveness (BCo, -), and springiness (BSp, -) were obtained by utilizing the combination of two strain (15% or 30%) and two duration between cycles (2 s and 10 s) as TPA operational settings. The statistical evaluation was conducted by one-way ANOVA, and the means of each storage humidity were separated according to the Tukey-HSD test (P = 0.05). The data presented in this article was used to select the Texture Profile Analysis operational settings utilized in the article entitled “Influence of water loss on mechanical properties of stored blueberries” Rivera et al. [1].
- ItemInfluence of water loss on mechanical properties of stored blueberries(Elsevier, 27/02/2021) Rivera S; Kerckhoffs H; Sofkova-Bobcheva S; Hutchins D; East AMoisture loss is considered a main cause of blueberry softening during postharvest storage. However, the causal relationship between softening and water loss has only previously been described by force to 1 mm compression. This study was performed to identify suitable instrumental tests that allow the separation of blueberries with different water loss values during storage. Mechanical properties were measured by double compression (Texture Profile Analysis) and puncture test. Variability on blueberry mechanical properties was created by regulating storage humidity and consequently water loss. As water loss increases during storage, hardness slope (slope of a straight line drawn between the trigger force of 0.06 N and the force at 15 % strain) obtained by the compression test reduces, and the displacement at berry skin break obtained by puncture test, increases. Therefore, these parameters can be potentially used to quantify mechanical changes in stored blueberries.
- ItemNon-destructive firmness assessment of ‘SunGold’ kiwifruit a three-year study(Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2024-02-14) Sneddon T; Rivera S; Li M; Heyes J; East A; Golding JKiwifruit (Actinidia chinensis var. chinensis) firmness is routinely measured in a destructive manner for decision-making purposes. Thus, a population’s quality is inferred by measuring a sample from that population. Consequently, studies have investigated non-destructive techniques for measuring fruit firmness. However, most of these studies have been restricted to a single season or focused on performance over long-term storage. This work compared non-destructive compression (1 mm deformation) and acoustic stiffness with flesh firmness measured with a penetrometer across three seasons. ‘SunGold’ kiwifruit were harvested from 11, 9 and 3 orchards on multiple occasions in 2020, 2021 and 2022, respectively. Kiwifruit was freighted to Palmerston North and assessed on arrival. Thirty fruit per orchard were measured on lab arrival, whilst 24 fruit per orchard were stored for two weeks at 0°C prior to assessment. The non-destructive methods had a strong (r2 > 0.89–0.92) segmented correlation with flesh firmness (0.52–10 kgf). Flesh firmness could be adequately estimated with the non-destructive methods within a season. However, segmented regression performance was reduced when predicting for a season outside of the training population. Nonetheless, these non-destructive methods may be useful for estimating flesh firmness at harvest and after short-term storage (2 weeks at 0 °C).
- ItemSegregation of ‘Hayward’ kiwifruit for storage potential using Vis-NIR spectroscopy(Elsevier BV, 2022-07) Li M; Pullanagari R; Yule I; East AKiwifruit are often harvested unripe and kept in local coolstores for extended periods of time before being marketed. Many pre-harvest factors contribute to variation in fruit quality at harvest and during coolstorage, resulting in the difficulty in segregating fruit for their storage potential. The ability to forecast storage potential, both within and between populations of fruit, could enable segregation systems to be implemented at harvest to assist with inventory decision making and improve profitability. Visible-near infrared (Vis-NIR) spectroscopy is one of the most commonly used non-destructive techniques for estimation of internal quality of kiwifruit. Whilst many previous attempts focused on instantaneous quantification of quality attributes, the objective of this work was to investigate the use of Vis-NIR spectroscopy utilised at harvest to qualitatively forecast storage potential of individual or batches of kiwifruit. Commercially sourced ‘Hayward’ kiwifruit capturing large variability of storability were measured non-destructively at harvest using Vis-NIR spectrometer, and then assessed at 75, 100, 125 and 150 days after coolstorage at 0 °C. Machine learning classification models were developed using at-harvest Vis-NIR spectral data, to segregate storability of kiwifruit into two groups based on the export FF criterion of 9.8 N. The best prediction was obtained for fruit stored at 0 °C for 125 days: approximately 54% of the soft fruit (short storability) and 79% of the good fruit (long storability) could be predicted. Further novelty of this work lies within an independent external validation using data collected from a new season. Kiwifruit were repacked at harvest based on their potential storability predicted by the developed model, with the actual post-storage performance of the same fruit assessed to evaluate model robustness. Segregation between grower lines at harvest achieved 30% reduction in soft fruit after storage. Should the model be applied in the industry to enable sequential marketing, significant costs could be saved because of reduced fruit loss, repacking and condition checking costs.
- ItemThe responses of ‘Hayward’ kiwifruit to ethylene during regular and controlled atmosphere storage(Taylor and Francis Groupon behalf of the Royal Society of New Zealand, 2024-05-08) Han Y; Heyes J; Glowacz M; Nicholson S; Jeffery P; East A; Li MMaintaining kiwifruit firmness is key to global supply chain. Controlled atmosphere (CA) technology can maintain kiwifruit quality. However, there is a risk of ethylene (C2H4) accumulation in CA that may accelerate kiwifruit softening. The objectives of this study were to determine the impact of ethylene on kiwifruit quality in CA. ‘Hayward’ kiwifruit were stored in air and CA (5% CO2 + 2% O2) at 0°C, 95% RH for 13 weeks. Ethylene at concentrations of 10, 100, 1000 nL·L−1 was added after 3 weeks of storage. The responses of kiwifruit to ethylene were dose-dependent in both air and CA storage. Ethylene-induced kiwifruit softening was delayed and slowed by CA. However, white-core inclusions (WCI) disorder was observed after 8 weeks of exposure to 100 and 1000 nL·L−1 ethylene in CA. The lowest concentrations of ethylene (≤ 10 nL·L−1) in CA did not influence kiwifruit quality. This work demonstrates that kiwifruit sensitivity to ethylene is lower in CA than that in air, but excessive softening and WCI may negatively impact kiwifruit quality when exposed to a high ethylene concentration in CA for extended periods. Hence, ethylene monitoring and management may be less critical in kiwifruit stored in CA but are required.
- ItemUnderstanding changes of laser backscattering imaging parameters through the kiwifruit softening process using time series analysis(Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2024-05-12) Yang Z; Li M; East A; Zude-Sasse M; Gould NDuring kiwifruit storage, quality monitoring is required for inventory planning and consistent quality maintenance. Commercial near-infrared (NIR) spectrophotometers showed reduced performance in the estimation of kiwifruit flesh firmness (FF) as the FF estimation is indirect and can be affected when both, textural structures and absorbing compounds, change during postharvest ripening. Laser backscattering imaging (LBI) records the backscattered signal after a single laser beam interacts with kiwifruit tissue, including merged information on light absorption and scattering. Measurements were carried out at 830 nm, where scattering is most dominant. In this work, time series of kiwifruit ‘Zesy002’ (n = 30) and ‘Hayward’ (n = 30) LBI were collected through the postharvest ripening during a 15-day shelf life at 20°C. Four LBI parameters capturing DIP, FWHM, SLP and HWQM were selected in this study. ‘‘Zesy002’ DIP, FWHM, SLP, and HWQM increased approx. 0.6 cm, 0.2 cm, 0.3 and 0.14 cm, respectively. ‘Hayward’ LBI increased approx. 0.2 cm, 0.1 cm, 0.2 and 0.04 cm, respectively. Different initial LBI values between cultivars and LBI changes may reflect the actual stage of softening, affected by kiwifruit ripeness. In conclusion, time series analysis could be useful in describing kiwifruit LBI change during ripening and making forecasts.
