The fermentation of whole wheat flour by Pediococcus pentosaceus / Fermentación de harina de trigo integral con Pediococcus pentosaceus

Abstract

A whole wheat flour:water brew (1:3) was fermented (at 32 °C) with a Pediococcus pentosaceus culture at inoculation levels ( I) of log10 I = 0 (control), 5, 6, 7 and 8 cfu/g brew. A direct relationship was observed between the inoculation level and the absolute values of the b and c parameters of the fitted fermentation equation: pH = a + bt + ct2. The first derivative of the fermentation equation was used to determine the duration of the lag phase period. When the inoculation level was increased from log 10 I = 0 to log10 I = 8 cfu/g brew the lag phase period ( Lp) and the fermentation time ( t) decreased from 5.2 to 0.8 h and from 18.0 to 4.2 h, respectively. The model lag phase period and the model fermentation time at inoculation levels other than those examined in this study were calculated using the equa tions LpM= 5.2 + 0.0245 I - 0.0714 I2 and tM5.0 = 18 - 1.15 I- 0.075 I2, respectively. The acid production phase comprised 68% of the fermentation period. The fermentation rate ( F) within each of the three periods of the fermentation increased as the inoculation level increased. The acid production rate- inoculation plot showed a discontinuity at an inoculation level of log10 I = 7.0 cfu/g brew.