Potency of UF system in concentrating corn (Zea mays var. indentata) hydrolyzate as fortificant of natural folic acid

Abstract

Ultrafiltration (UF) membrane system in concentrating corn (Zea mays var. indentata) hydrolyzate equipped in Stirred Ultrafiltration Cell (SUFC) was done as a reference for process toward larger scale (semi pilot scale) to get potential concentrate of fortificant of natural folic acid. Concentration of yellow and white corn hydrolyzates as a result of hydrolysis of corn by crude protease enzyme of Rhizopus oligosporus strain C1 was performed through UF membrane (MWCO 20000 Da.) under stirring speed 200, 300 and 400 rpm, and trans-membrane pressure (TMP) 20, 30 and 40 psia for 30 minutes, respectively. The result of experiment work showed that based on recovery of folic acid, the best SUFC process system on both yellow and white corn hydrolyzates were obtained under stirring speed 200 rpm and TMP 40 psia, and stirring speed 200 rpm and TMP 20 psia, respectively. In these process conditions, it generates concentrate with composition of folic acid of 89.79 and 156.73 µg/mL, dissolved protein of 1.010 and 0.668 mg/mL, total solids of 75.42 and 78.43%, total sugars of 273.14 and 298.89 mg/mL, and reducing sugars of 3.71 and 9.77 mg/mL. In these process conditions, UF membrane system was technically able to concentrate yellow corn hydrolyzate 2.64% and white corn hydrolyzate 10.64%. Identification on molecular weight (MW) of folic acid from yellow and white corn hydrolyzate displays mass spectra with dominant folic acid monomer with MW of 442.57 and 442.54 Dalton (Da.).