Serra Sara, Anthony Brendon, Boscolo Sesillo Francesca, Masia Andrea, Musacchi Stefano
Department of Horticulture, Tree Fruit and Research Extension Center (TFREC), 1100 N. Western Avenue, Washington State University, Wenatchee, WA 98801, USA.
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Diego, CA 92093, USA.
Foods. 2021 Jan 18;10(1):186. doi: 10.3390/foods10010186.
Phenolic compounds in fruit provide human health benefits, and they contribute to color, taste, and the preservation of post-harvest fruit quality. Phenolic compounds also serve as modifiers of enzymatic activity, whether inhibition or stimulation. Polyphenol oxidases (PPO) and peroxidases (POD) use phenolic compounds as substrates in oxidative browning. Apple browning leads to flesh color, taste, texture, and flavor degradation, representing a drawback for the variety and its' market appraisal. This study was conducted to investigate the process of browning in 14 apple cultivars throughout post-harvest at three-time points: immediately (T0), one hour (T1), and 24 h (T2) after apples were cut in half. Color parameters L* (lightness), a* (red/green), b* (yellow/blue) were measured, and chroma (Δ*) and color (ΔE) were calculated to quantify differences between T0₋T1 and T1₋T2 on the fruit surface. Enzymatic activity (PPO, POD) and phenolic composition were also quantified for each cultivar. 'Granny Smith' and 'Cripps Pink' browned minimally. In contrast, 'Fiesta' and 'Mondial Gala' browned severely, reporting high enzymatic activity and quantified phenolic concentration (QPC). Phenolic compound polymerization appears to play a significant role in enzymatic inhibition. 'Topaz' does not fit the high QPC, PPO, and browning formula, suggesting alternative pathways that contribute to apple browning.
水果中的酚类化合物对人体健康有益，它们影响水果的颜色、味道以及采后果实品质的保存。酚类化合物还可作为酶活性的调节剂，起到抑制或刺激的作用。多酚氧化酶（PPO）和过氧化物酶（POD）在氧化褐变过程中以酚类化合物为底物。苹果褐变会导致果肉颜色、味道、质地和风味变差，这对苹果品种及其市场评价来说是一个缺点。本研究旨在调查14个苹果品种在采后三个时间点（即苹果切成两半后立即（T0）、一小时后（T1）和24小时后（T2））的褐变过程。测量颜色参数L*（亮度）、a*（红/绿）、b*（黄/蓝），并计算色度（Δ*）和色差（ΔE）以量化果实表面T0₋T1和T1₋T2之间的差异。还对每个品种的酶活性（PPO、POD）和酚类成分进行了量化。“澳洲青苹”和“粉红女士”褐变程度最小。相比之下，“嘉年华”和“世界 gala”褐变严重，酶活性高且酚类浓度（QPC）量化值高。酚类化合物聚合似乎在酶抑制中起重要作用。“托帕石”不符合高QPC、PPO和褐变模式，这表明存在导致苹果褐变的其他途径。
