Optimization of anthocyanins extraction process from black soybean seed coat for the preparation of maize-based functional food

Abstract

Black soybean seed coat has a considerable content of anthocyanins which can providea positive effect on the health of the consumers through food products enriched with the extracts of these valuable bioactive compounds. Nevertheless, the use of soybean seed coat, a by-product from soybean processing, additionally valorizes this raw material.The possibility of enrichment of sweet maize grains with anthocyanin extract was investigated. Several procedures with acetic acid were applied in the experiments of anthocyanins extraction from black soybean seed coat. During the marination process, the grains were stained, changing their standard yellow color to a crimson red. Since the brines with the addition of citric acid became cloudy (opalescent) after some time, lactic acid was used as an anthocyanin stabilizer in the continuation of the research. Depending on the extraction conditions, the spectrophotometrically determined content of total anthocyanins in the solution varied from 3541.90 to 5387.70 μg CGE/g d.m., and in the marinated maize grain between 179.89 and 286.05 μg CGE/g d.m. After seven days, the total anthocyanin content in the grain did not increase significantly, so this aging period was selected as optimal for marinating maize products.

Semenjača crne soje ima značajan sadržaj antocijana, koji mogu pozitivno uticati na zdravlje potrošača kroz prehrambene proizvode obogaćene ekstraktima ovih vrednih bioaktivnih jedinjenja. Istovremeno, upotrebom sojine semenjače, sporednog proizvoda prerade soje, dodatno se valorizuje ova sirovinu. Ispitivana je mogućnost obogaćivanja zrna kukuruza šećerca ekstraktom antocijana. U eksperimentima ekstrakcije antocijana iz semenjače crne soje primenjeno je nekoliko postupaka sa sirćetnom kiselinom. Tokom procesa mariniranja, zrna su promenila boju, menjajući standardnu žutu boju u tamnocrvenu. S obzirom da su posle izvesnog vremena nalivi za mariniranje sa dodatkom limunske kiseline postali zamućeni (opalescentni), u nastavku istraživanja je korišćena mlečna kiselina kao stabilizator antocijana. U zavisnosti od uslova ekstrakcije, spektrofotometrijski utvrđen sadržaj ukupnih antocijana u rastvoru varirao je od 3541,90 do 5387,70 mg CGE/g d.m., a u zrnu mariniranog kukuruza između 179,89 i 286,05 mg CGE/g. Posle sedam dana, ukupan sadržaj antocijana u zrnu nije značajno povećan, pa je ovaj period odležavanja izabran kao optimalan za mariniranje proizvoda od kukuruza.