Herppich Werner B, Maggioni Marco, Huyskens-Keil Susanne, Kabelitz Tina, Hassenberg Karin
Department of Horticultural Engineering, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469 Potsdam, Germany.
Division Urban Plant Ecophysiology, Research Group Quality Dynamics/Postharvest Physiology, Humboldt-Universität zu Berlin, Lentzeallee 55/57, 14195 Berlin, Germany.
Foods. 2020 Jun 22;9(6):820. doi: 10.3390/foods9060820.
For fresh-cut salad production, hot-water treatment (HWT) needs optimization in terms of temperature and duration to guarantee a gentle and non-stressing processing to fully retain product quality besides an effective sanitation. One major initial target of heat treatment is photosynthesis, making it a suitable and sensitive marker for HWT effects. Chlorophyll fluorescence imaging (CFI) is a rapid and non-invasive tool to evaluate respective plant responses. Following practical applications in fruit salad production, apples of colored and of green-ripe cultivars ('Braeburn', 'Fuji', 'Greenstar', 'Granny Smith'), obtained from a local fruit salad producer, were hot-water treated from 44 to 70 °C for 30 to 300 s. One day after HWT and after 7 days of storage at 4 °C, CFI and remission spectroscopy were applied to evaluating temperature effects on photosynthetic activity, on contents of fruit pigments (chlorophylls, anthocyanins), and on various relevant quality parameters of intact apples. In 'Braeburn' apples, short-term HWT at 55 °C for 30 to 120 s avoided any heat injuries and quality losses. The samples of the other three cultivars turned out to be less sensitive and may be short-term heat-treated at temperatures of up to 60 °C for the same time. CFI proved to be a rapid, sensitive, and effective tool for process optimization of apples, closely reflecting the cultivar- or batch-specificity of heat effects on produce photosynthesis.
对于鲜切沙拉的生产，热水处理（HWT）需要在温度和持续时间方面进行优化，以确保温和且无胁迫的加工过程，除了有效杀菌外，还能充分保持产品质量。热处理的一个主要初始目标是光合作用，使其成为评估热水处理效果的合适且敏感的指标。叶绿素荧光成像（CFI）是一种快速且非侵入性的工具，用于评估植物的相应反应。在水果沙拉生产中的实际应用之后，从当地水果沙拉生产商处获得的有色和绿熟品种（“Braeburn”、“富士”、“Greenstar”、“澳洲青苹”）的苹果在44至70°C下进行了30至300秒的热水处理。在热水处理一天后以及在4°C下储存7天后，应用CFI和反射光谱来评估温度对光合活性、果实色素（叶绿素、花青素）含量以及完整苹果各种相关质量参数的影响。在“Braeburn”苹果中，55°C下30至120秒的短期热水处理避免了任何热损伤和质量损失。其他三个品种的样品对热不太敏感，在相同时间内可在高达60°C的温度下进行短期热处理。CFI被证明是优化苹果加工过程的一种快速、灵敏且有效的工具，能密切反映热处理对产品光合作用影响的品种或批次特异性。
