Micronutrient composition of milling streams of traditional wheat cultivars from Serbia

Abstract

The deficiency of micronutrients in the human diet is widely recognised as a global problem. The objective of this study was to assess the content of two essential minerals, iron and zinc, in milling streams of old heritage wheat cultivars that have not been produced for more than a half-century to discover potential parent lines with high mineral content for breeding. Kernel size of seven Serbian old wheat cultivars was evaluated for ash content, thousand-grain weight and share of specific kernel fractions. Three cultivars, Crnozrna, Rumska Crvenka and Stara Banatka, were selected as the most appropriate for milling and further analysis of mineral content in the milling streams. The cultivars were milled in a laboratory mill to obtain six flour and two byproduct streams. At the same time, iron and zinc content was determined on a graphite furnace atomic absorption spectrometer. After mixing all six flour streams obtained from each cultivar, three different flour types were obtained. The flour with the highest ash content was the "1100" type originating from cultivar Stara Banatka, characterized by the highest iron and zinc content (54.9 mg/kg d. b. and 5.407 mg/kg d. b., respectively). It was estimated that consumption of a daily average bread portion (166 g according to national statistical data) made from Stara Banatka flour could provide about 90% of the recommended daily intake for iron. Therefore, Stara Banatka may be a target cultivar for wheat breeders searching for high-iron parent wheat lines.

Nedostatak mikronutrijenata u ljudskoj ishrani predstavlja globalni problem. Cilj ovog rada je određivanje sadržaja dva esencijalna metala, gvožđa (Fe) i cinka (Zn) u frakcijama dobijenim pri mlevenju tradicionalnih starih sorti pšenice koje se nisu proizvodile više od pola veka u cilju pronalaženja frakcije sa visokim sadržajem esencijalnih metala koje bi poslužile za oplemenjivanje. Kod sedam starih srpskih sorti pšenica određeni su sledeći parametri veličine zrna: sadržaj pepela, masa hiljadu zrna i udeo specifičnih frakcija zrna. Crnozrna, Rumska Crvenka i Stara Banatka bile su odabrane sorte kao najpogodnije za mlevenje, radi kvantitativnog određivanja sadržaja Fe i Zn u dobijenim frakcijama. Mlevenje je izvršeno na laboratorijskom mlinu da bi se dobilo šest proizvoda mlevanja i dva nusproizvoda, a sadržaj Fe i Zn određen je atomskim apsorpcionim spektrometrom sa grafitnom kivetom. Namešavanjem šest proizvoda mlevenja svake sorte dobijene su tri različite vrste brašna. Najveći sadržaj pepela određen je za brašno tip „1100“, dobijeno iz sorte Stare Banatke, koje je takođe imalo najveći sadržaj Fe i Zn (54,9 mg/kg s.m. i 5,407 mg/kg s.m., redom). Konzumiranjem standardne porcije hleba u Srbiji (166 g/dan) dobijene od brašna Stare Banatke bilo bi moguće obezbediti oko 90% preporučenog dnevnog unosa Fe. Stoga, Stara Banatka predstavlja sortu koja bi mogla da bude izvor visokog sadržaja Fe i da se koristi za oplemenjivanje, radi stvranja novih linija pšenice sa visokim sadržajem ovog minerala.