Abstract Currently, agriculture has shifted to green production, in which the recycling of post-production by-products is a key issue. In the present work, by-products such as pomelos were studied to promote consumption and enhance the value of pomelo. From pomelo material, essential oils extracted from pomelo peels, pectin, and drying pomelo products have been diversified. In the extraction process of essential oils, the hydrodistillation method was applied in conjunction with the response surface method to obtain the optimal conditions of influence factors. These essential oils were quantified as well as determined for components by GC-MS. The pectin recognition process was done by immersion method in HCl acid (pH 2) and the drying process was made with a heat pump dryer under the effects of drying temperature, drying time and wind rate. The results of the essential oil products reached the highest (0.88 ±0.006 g) at the material size of 3 mm, the distillation time of 27 min, and the ratio of raw materials/solvents of 1/12 g/mL. The main components found in pomelo peeling essential oils included limonene (71.768%), γ-terponene (12,847%), α-Phellandrene (2.979%), β-myrcene (2.668%), 1R-α-pinene (2,656%), and β-pinene (1,191%). The pectin content was the highest under the temperature of 90 °C, extraction time of 60 min and ratio/solvent ratio of 1:32 g/mL. Under these extraction conditions, 48% of concentrated pectin content was obtained. Surveying conditions for drying white pomelo peels are capable of reversing: refunded drying pomelos are drying heat pumps in the following conditions: 50 °C drying temperature, the drying time of 90 min, and wind rate of 12 m/s. Product with hardness 309.862 N.

中文翻译：

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柚子皮的产品多样化。精油、果胶和半干柚子皮

摘要 目前，农业已转向绿色生产，其中产后副产品的回收利用是一个关键问题。在目前的工作中，研究了柚子等副产品，以促进消费并提高柚子的价值。从柚子原料中，从柚子皮中提取的精油、果胶和干柚子产品已经多样化。在精油的提取过程中，采用加氢蒸馏法与响应面法相结合，得到影响因素的最佳条件。通过 GC-MS 对这些精油进行量化和成分测定。果胶识别过程采用 HCl 酸 (pH 2) 浸渍法进行，干燥过程采用热泵干燥机在干燥温度的影响下进行，干燥时间和风速。在原料粒径为3 mm、蒸馏时间为27 min、原料/溶剂比为1/12 g/mL时，精油产品的结果最高（0.88±0.006 g）。柚子皮精油中发现的主要成分包括柠檬烯（71.768%）、γ-萜烯（12,847%）、α-水芹烯（2.979%）、β-月桂烯（2.668%）、1R-α-蒎烯（2,656%）、和β-蒎烯（1,191%）。在温度90 ℃、提取时间60 min、溶剂比1:32 g/mL时果胶含量最高。在这些提取条件下，获得了 48% 的浓缩果胶含量。白柚皮烘干调查条件可逆转：退烘干柚为烘干热泵，烘干温度50℃，烘干时间90min，风速为 12 m/s。硬度为 309.862 N 的产品。