The possibility of using horseradish leaves pomace in the food industry

Abstract

Horseradish is a plant that belongs to the Brassicaceae family and is native to southeastern Europe and western Asia. It is cultivated for its succulent and spicy root, which is used as a seasoning for meat, soups, seafood, etc. The horseradish root has a much higher culinary value than the horseradish leaf, which is usually discarded with the rest of the aboveground biomass and has no use in the food industry. However, the horseradish leaf can be used in the diet in the form of salad or in the preparation of various dishes, to which it gives a characteristic spicy flavor. The biological activity of horseradish is expressed as antimicrobial, insecticidal, anticoagulant, and gastro-protective effects of isothiocyanates, compounds formed by the hydrolysis of glucosinolates under the action of the enzyme myrosinase. In addition, the horseradish leaf is rich in vitamin C, polyphenols, and flavonoids, which is why it is desirable to press it to obtain juice that can be used in the food industry. Moreover, pressing leaves behind a pomace that could also potentially be used in the food industry. Therefore, this research aimed to analyze the content of phenolic compounds and the antioxidant potential of the horseradish leaves pomace, to achieve the full utilization of the plant and reduce biomass loss. Total phenolic content (TPC), total flavonoid content (TFC), total phenolic acid content (TPAC), and antioxidant activity (DPPH, ABTS, and FRAP methods) were determined by standard spectrophotometric methods. The results showed that the quantitative content of total phenolic compounds, flavonoids, and phenolic acids in horseradish leaves pomace, after pressing and obtaining juice, was 7825.50 ± 749.20 mg GAE/kg FW (fresh weight - FW), 9460.00 ± 138.60 mg CE/ kg FW and 8905.50 ± 336.90 mg CAE/kg FW, respectively. In the analysis of antioxidant activity, it was found that all three methods indicate the presence of antioxidant potential of horseradish leaves pomace, namely: 9.00 ± 0.70 mmol TE/kg FW (DPPH), 42.30 ± 3.80 mmol TE/kg FW (ABTS ) and 17.30 ± 0.60 mmol TE/kg FW (FRAP). Based on the obtained results, it can be concluded that horseradish leaves pomace contains significant amounts of polyphenolic compounds and high antioxidant potential, making it a suitable raw material for the food industry, both from the point of view of waste prevention and potential enrichment of food products to which it is added (as a seasoning for salads and dehydrated soups, etc.).