Yeo Hyunho, Kim Si-Yeon, Shahbaz Hafiz Muhammad, Jeong Se-Ho, Ju Hye-In, Jeon Ji-Hee, Lee Dong-Un
Department of Food Science and Technology, Chung-Ang University, Anseong 17546, Republic of Korea.
R&D Center, Ottogi Co., Ltd., Anyang 14060, Republic of Korea.
Foods. 2024 Jan 3;13(1):164. doi: 10.3390/foods13010164.
This study applied pulsed electric fields (PEFs) to accelerate the withering and drying processes during cold-brewed black tea production. PEF pretreatment was administered at 1.0, 1.5, and 2.0 kV/cm electric field strengths, combined with varying withering times from 8 to 12 hr. During the 12-hour withering process, the redness value (a*) and total color change (∆E) of PEF-treated leaves significantly increased ( < 0.05). Furthermore, the homogenous redness of tea leaves during fermentation depended on the PEF strength applied. In addition, PEF pretreatment remarkably reduced the drying time, up to a 50% reduction at a 2.0 kV/cm field strength. Additionally, the 2.0 kV/cm PEF-pretreated black tea exhibited a notable 42% increase in theaflavin (TF) content and a 54% increase in thearubigin (TR) content. Sensory evaluation scores were highest for black tea that received PEF pretreatment at 2.0 kV/cm. These findings highlight the significant potential of PEFs in enhancing the efficiency of withering and drying processes while positively impacting the physicochemical and sensory properties of cold-brewed black tea.
本研究应用脉冲电场（PEFs）来加速冷泡红茶生产过程中的萎凋和干燥过程。在1.0、1.5和2.0 kV/cm的电场强度下进行PEF预处理，并结合8至12小时不等的萎凋时间。在12小时的萎凋过程中，经PEF处理的叶片的红色值（a*）和总颜色变化（∆E）显著增加（<0.05）。此外，发酵过程中茶叶的均匀红色度取决于所施加的PEF强度。此外，PEF预处理显著缩短了干燥时间，在2.0 kV/cm的场强下最多可缩短50%。此外，经2.0 kV/cm PEF预处理的红茶的茶黄素（TF）含量显著增加了42%，茶红素（TR）含量增加了54%。感官评价得分最高的是在2.0 kV/cm下接受PEF预处理的红茶。这些发现突出了PEFs在提高萎凋和干燥过程效率的同时，对冷泡红茶的理化和感官特性产生积极影响的巨大潜力。
