AACC International 2012 Meeting Abstract - Solid state fermentation of maize (Zea mays L.): Effect of fermentation time on antioxidant activity

Poster Presentation Abstract

123-P

Solid state fermentation of maize (Zea mays L.): Effect of fermentation time on antioxidant activity
M. L. GUZMÁN URIARTE (1), L. M. Sánchez Magaña (1), E. O. Cuevas Rodriguez (1), S. Mora Rochín (1), A. Valdez Ortiz (1), R. Gutiérrez Dorado (1), J. Milán Carrillo (1), C. Reyes Moreno (1)
(1) Universidad Autónoma de Sinaloa, Culiacán, Sinaloa, Mexico

The objective of this study was to evaluate the effect of fermentation time on the antioxidant activity of maize (Zea mays L.). Fragmented maize grains were soaked (25°C/16h) in acetic acid solution (pH 3.0). Fragmented grains were drained and then cooked in acidified distilled water (pH 3.0) at 90°C for 30 min, cooled (25°C/4 h), inoculated with a suspension of R. oligosporus NRRL 2710 (1 x 10⁶ spores/ml), and packed in perforated polyethylene bags (15 x 15 cm). SSF was performed at 35°C and fermentation times of 24, 36, 48, 60, 72, 84, 96 and 108 h. The resulting fermented maize (tempehs) from each fermentation time were dried (50°C/12 h), cooled (25°C), and milled (80-US mesh = 0.180 mm). Fermented maize flours were packed and stored at 4°C. The fermentation time increased (p < 0.05) the total phenolic content (TPC) and antioxidant activities (ORAC value) of maize grains until 84 h of fermentation; after this time the TPC and ORAC value were not statistical differences (p < 0.05). The best combination of SSF process variables to obtain maize tempeh flour with the highest antioxidant activity was 35°C/84 h. Fermented maize flour produced with this combination of process variables showed higher (p < 0.05) ORAC value (+46%), TPC (+29%), and proteins (+34.9%) than the unfermented maize. Furthermore, this fermented maize flour showed higher (p < 0.05) dispersability and water absorption index, and lower (p < 0.05) water solubility index, pH and Hunter ‘L’ value than unfermented maize flour. Fermented maize flour obtained with the best combination of SSF process variables might be considered for the fortification of widely consumed cereal based food products and also for the prevention of pathologies associated with oxidative stress.