Horseradish contains many bioactive compounds with antioxidant activity. The current study aimed to evaluate the effect of various wall materials and their ratios on the physical properties and bioactive-compound retention and stability in microencapsulated horseradish leaf and root juices. Horseradish juice was microencapsulated using maltodextrin, maltodextrin/gum Arabic, soy protein isolate, and starch with three different core-to-wall ratios. The total phenolic, total flavonoid, total flavan-3-ol, and total phenolic-acid contents, as well as antioxidant activity, were determined using spectrophotometric methods, whereas individual phenol profiles were determined by high-performance liquid chromatography (HPLC). Multivariate analysis of variance showed that plant material, wall material, and core-to-wall ratio had a significant effect on the bioactive-compound retention and antioxidant-activity preservation. Microcapsules produced from horseradish leaf juice had a significantly higher content of phenolic compounds and antioxidant activity compared to root-juice microcapsules. However, better retention was observed for microencapsulated horseradish root juice. Maltodextrin and maltodextrin/gum Arabic were the most effective wall materials for the retention of bioactive compounds, while they also had a smaller particle size and better solubility. The horseradish-juice microcapsules possess a high content of rutin. The highest stability of bioactive compounds after storage was found at a core-to-wall ratio of 20:80.

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.

Health-conscious consumers are interested in products with an increased bioactive compound content. The nutritional quality is considered both as a stability and bioaccessibility concern. The aim of this study was to investigate the effect of horseradish products (horseradish root pomace, horseradish leaf pomace, microencapsulated horseradish root and leaf juice) on the physicochemical properties of biscuits, as well as to assess in vitro bioavailability and activity of phenolics. The bioactive compounds and antioxidant activity of horseradish products, which were used to replace the flour in biscuit dough, were analysed. Physicochemical parameters (pH, water activity, colour, phenolic compound contents, and antioxidant activities) were determined for the biscuits. Horseradish products compared to other cruciferous vegetables have a high content of phenolic compounds, as well as high antioxidant activity. Higher levels of bioactive compounds were found in microencapsulated horseradish leaf juice, compared to the other horseradish products used in the study. Enriched biscuits had a significantly higher total phenolic content (TPC) and antioxidant activity, compared to the control. After 180-day storage, TPC of biscuits with horseradish root products did not change significantly but in biscuits with horseradish leaf products it decreased by 2729%. The bioaccessibility index of phenolic compounds after in vitro digestion of enriched biscuits ranged between 2.19 and 2.99. Microencapsulated horseradish leaf juice was more effective in enriching biscuits with bioactive compounds. The developed biscuits enriched with horseradish products could meet consumer expectations for healthy, functional food.y