The effects that different varieties of fertiliser have on specialized metabolite fruit of Okra (Abelmoschus esculentus L.)

Bamija (Abelmoschus esculentus L.) je jednogodišnja, grmolika biljka koja pripada porodici Malvaceae te se pretežito uzgaja u tropskim i suptropskim područjima. Nutritivno je važna sirovina zbog visokog udjela prehrambenih vlakana te vitamina C. Prilikom uzgoja gnojidbom se značajno može utjecati na konačnu kvalitetu namirnice. Cilj istraživanja bio je utvrditi utjecaj ekoloških gnojiva (1 komercijalni i 2 tradicionalna) u usporedbi s klasičnim mineralnim gnojivom i kontrolom (varijante bez gnojidbe) na sadržaj sekundarnih specijaliziranih metabolita i nutritivni sastav ploda bamije. Kod plodova bamije tretiranih tradicionalnim gnojivom od gaveza utvrđen je najviši sadržaj topljive suhe tvari (1 ,5 %), vitamina C (25,06 mg/100 g svježe tvari) i ukupnih klorofila (0,08 mg/g), dok je kod plodova biljaka tretiranih ekološkim gnojivom „Siforga“ utvrđen najniži sadržaj topljive suhe tvari (6,40 %), vitamina C (18,61 mg/100 g svježe tvari), ukupnih fenola (104,82 mg GAE/100 g svježe tvari) i ukupnih klorofila (0,04 mg/g). Temeljem rezultata istraživanja može se zaključiti kako je tretman biljaka tradicionalnim ekološkim gnojivima od gaveza i koprive značajno pozitivno utjecao na sadržaj sekundarnih specijaliziranih metabolita i nutritivni sastav ploda bamije u usporedbi s mineralnim i biokomercijalnim gnojivom. S obzirom na dobivene rezultate, u svrhu gnojidbe preporuča se korištenje tradicionalnih ekoloških gnojiva uz istovremeno smanjen unos mineralnih koji onečišduju okoliš i dovode do degradacije tla.Okra (Abelmoschus esculentus L.) is an annual, shrubby plant belonging to the Malvaceae family, mainly grows in tropical and subtropical areas. Raw material is nutritionally important because of the high content of dietary fibre and vitamin C. When grown, fertilization can significantly affect the final quality of the food. The aim of the study was to determine the influence of organic fertilizers (1 commercial and 2 traditional) compared to conventional mineral fertilizer and control (non-fertilizer variants) on the content of secondary specialized metabolites and nutritional value of okra fruit. The highest content of total soluble solids (10.50 %), vitamin C (25.06 mg/100 g FW) and total chlorophylls (0.08 mg/g) was determined in fruits treated with traditional comfrey fertilizer, while in plant fruits treated with organic fertilizer 'Siforga' the lowest content of total soluble solids (6.40 %), vitamin C (18.61 mg/100 g FW), total phenols (104.82 mg GAE/100 g FW) and total chlorophylls (0.04 mg/g) was determined. Based on the obtained results, it can be concluded that the treatment of okra plants with traditional organic fertilizers of comfrey and nettle had a significant positive effect on the content of secondary specialized metabolites and nutritional composition of okra fruit compared to mineral and bio commercial fertilizer. Given the results, for the fertilization purposes, it is recommended the use of traditional organic fertilizers, simultaneously reducing the intake of mineral fertilizers that pollute the environment and lead to soil degradation