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    The effect of physical damage on carrots and carrots respiration : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Palmerston North, New Zealand
    (Massey University, 2024) Guo, YuHao
    This thesis aims to investigate the influence of physical damage on carrots' respiration rate (RR). The paper comprises eight experiments categorised into two parts. Firstly, research on carrot respiration rate was conducted. To provide a more comprehensive understanding of carrot respiration, factors that may affect carrot respiration; such as the carrot properties and temperature were studied. Linear regression, Monte-Carlo simulation, and other statistical tools, were used to describe how temperature plays a significant role in affecting respiration rate. This second part of the research investigated the influence of physical damage on the respiration rate of carrots. This work introduced the concepts of respiration rate gap and damage density to reflect the damage-enhanced respiration rate and damage level, respectively. A relationship between damage density and damage-enhanced respiration rate was built, which indicated that both low-density and high-density damage have limited influence on respiration rate.
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    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 Ignacio
    By 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.
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    Analysis of the Antioxidant Mechanism of Ozone Treatment to Extend the Shelf Life and Storage Quality of ‘Korla’ Fragrant Pears Based on Label-Free Proteomics
    (MDPI (Basel, Switzerland), 2024-05-01) Lin S; Zhang X; Li M; Zhang N; Dong C; Ji H; Zheng P; Ban Z; Mei X; Gu C; Chen C; Antunes MDC
    In this study, the physiological indicators, reactive oxygen species (ROS) levels, and activities and expressions of key enzymes related to ROS metabolism were monitored to explore the mechanism of ozone treatment on the shelf life of postharvest Korla fragrant pears. The results show that postharvest fragrant pears treated with ozone had a higher firmness and lower weight loss rate and decay rate during their shelf life, especially in the late stage. Ozone treatment could also delay the occurrence of the respiratory peak and reduce the peak value. The generation rate of superoxide anion (O2−), the hydrogen peroxide (H2O2) content, and the malondialdehyde (MDA) level were reduced in the ozone-treated group, while the activities of key enzymes, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), related to ROS metabolism in postharvest fragrant pears were stimulated by ozone treatment, especially in the middle and late stages of shelf life. Analysis of the proteomics results indicates that the POD family enzymes were the main target protein in postharvest fragrant pears treated by ozone during the middle and late stages of shelf life. The activity and expression of antioxidant-related enzymes in postharvest fragrant pears were stimulated by ozone to accelerate the metabolism of ROS and maintain high quality, especially in the middle and late shelf lives.