Abstract:

To select lactic acid bacteria stains for okra fermentation, single and mixed inoculums of two species of lactic
acid bacteria (Leuconostc mesenteroides and Lactobacillus plantarum) were investigated by measuring pH, total acid,
viable cell counts, volatile components and sensory evaluation of fermented okra juice. Lactobacillus plantarum when
inoculated singly grew rapidly in okra juice and reached nearly 107 CFU/mL and pH 4.5 after 24 h fermentation, whereas
Leuconostc mesenteroides alone was not useful for acid production during fermentation of okra juice. Fermentation with
a mixture of Leuconostc mesenteroides and Lactobacillus plantarum (2:1, V/V) fast reduced the pH to less than 4.5 (high
acid) and resulted in a large number of living lactic acid bacteria (108 CFU/mL). GC-MS results showed that fermented okra
juice was more conducive to producing flavor compounds through mixed-culture fermentation compared with pure-culture
fermentation. Sensory evaluation results also showed that mixed-culture fermentation of okra juice was more desirable
than single-strain fermentation. The best inoculum for okra juice was the 2:1 mixture (V/V) Leuconostc mesenteroides and
Lactobacillus plantarum. The optimal fermentation parameters were determined as 5%, 35 ℃ and 72 h for inoculum amount,
incubation temperature and fermentation duration, respectively .

Key words: okra, lactic acid fermentation, mixed bacteria fermentation, volatile components