Horseradish (Armoracia rusticana) leaves pomace, which contains high-value bioactive compounds, is the product resulting from pressing horseradish leaves for juice production. The aim of the current research was to investigate the effect of convective, microwave-vacuum and freeze-drying on the content of bioactive compounds in horseradish leaves pomace. Convective hot air-drying was performed at 40, 60 and 80 °C. The total phenolic content (TPC), total flavonoid content (TFC), total flavan-3-ol content, total phenolic acid content, total flavonol content, chlorophylls and total carotenoids, and antioxidant activity were determined by spectrophotometric methods. Individual profiles of phenols and organic acids are estimated by high-performance liquid chromatography (HPLC), but volatile compounds are estimated by gas chromatography (GC). Totally, 14 individual phenolic compounds, 8 organic acids, and 49 volatile compounds were analysed in the studied samples. The main phenolic compound identified in horseradish leaves pomace was rutin (3231 mg/100 g DW), among organic acids—quinic and malic acids, and volatile compounds—allyl isothiocyanate, 3-butenenitrile and benzyl alcohol. In the drying process, the content of some (total flavan-3-ols, total carotenoids content) compounds increased, but others (TPC, total organic acids content) decreased, and it was drying method-dependent. Freeze-drying caused the reduction of TPC by 29%, whereas convective drying by 53–59%. Fresh pomace contains such isothiocyanates as allyl isothiocyanate and butyl isothiocyanate, which were completely lost in the drying process. Freeze-drying allowed the best retention of various phenolic and volatile compounds in horseradish leaves pomace.

中文翻译：

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辣根叶渣的特征：酚类化合物的特性和抗氧化能力，有机酸，色素和挥发性化合物的含量

辣根（辣根）叶果渣，其中含有高价值的生物活性化合物，是将辣根叶压榨用于汁液生产的产品。当前研究的目的是研究对流，微波真空和冷冻干燥对辣根叶果渣中生物活性化合物含量的影响。对流热风干燥在40、60和80°C下进行。用分光光度法测定总酚含量（TPC），总黄酮含量（TFC），总黄烷-3-醇含量，总酚酸含量，总黄酮含量，叶绿素和总类胡萝卜素以及抗氧化活性。酚和有机酸的各自概况通过高效液相色谱（HPLC）估算，而挥发性化合物则通过气相色谱（GC）估算。总共14种酚类化合物，在研究的样品中分析了8种有机酸和49种挥发性化合物。在辣根叶果渣中鉴定出的主要酚类化合物是芦丁（3231 mg / 100 g DW），其中有机酸（奎宁酸和苹果酸）和挥发性化合物（异硫氰酸烯丙酯，3-丁烯腈和苄醇）。在干燥过程中，某些化合物（总黄烷-3-醇含量，总类胡萝卜素含量）的含量增加，而其他化合物（TPC，总有机酸含量）降低，这取决于干燥方法。冷冻干燥导致TPC降低29％，而对流干燥降低53-59％。新鲜的果渣含有异硫氰酸酯，例如烯丙基异硫氰酸酯和异硫氰酸丁酯，它们在干燥过程中完全消失。冷冻干燥可以使辣根叶果渣中各种酚类和挥发性化合物得到最佳保留。