Volatile compounds produced by Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei in single starter culture fermentations of Ghanaian maize dough

Abstract

Aims: To identify and compare the volatile compounds associated with maize dough samples prepared by spontaneous fermentation and by the use of added starter cultures in Ghana. Methods and Results: The starter cultures examined were Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei. For identification of aroma volatiles, extracts by the Likens-Nickerson simultaneous distillation and extraction technique were analysed by gas chromatography-mass spectrometry (GC-MS) and using a trained panel of four judges by GC-Olfactometry (GC-sniffing). Compounds identified by GC-MS in maize dough samples after 72 h of fermentation included 20 alcohols, 22 carbonyls, 11 esters, seven acids, a furan and three phenolic compounds. Of the total 64 volatile compounds, 51 were detected by GC-sniffing as contributing to the aroma of the different fermented dough samples. Spontaneously fermented maize dough was characterized by higher levels of carbonyl compounds while fermentations with added L. fermentum recorded the highest concentration of acetic acid. S. cerevisiae produced higher amounts of fusel alcohols and increasing levels of esters with fermentation time and C. krusei showed similarity to L. fermentum with lower levels of most volatiles identified. Conclusion: The present study has given a detailed picture of the aroma compounds in fermented maize and demonstrated that the predominant micro-organisms in fermented maize dough can be used as starter cultures to modify the aroma of fermented maize dough. Significance and Impact of the Study: The study has documented the advantage of using starter cultures in African traditional food processing and provided a scientific background for introducing better controlled fermentations.

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“…Similar pH values from 6.3 to 4.5 was reported by Egounlety and Syarief (1992) during the studies of ogi supplemented with tempe. A pH decline with corresponding rise in acidity in maize dough fermented with and without a starter culture was also reported by Annan et al (2003). The range of pH obtained especially towards the end of fermentation was enough to inhibit the growth of undesirable microorganisms, since bacteria growth occurs optimally at pH values 6-7.…”

Aroma profile of gowe, a traditional malted fermented sorghum beverage from Benin

“…The ability of selected microorganisms to modify taste, flavors and other characteristics of fermented products has been studied by several authors (Annan et al, 2003b, c;Mugula et al, 2003;Zorba et al, 2003;Gran et al, 2003;Ouoba et al, 2005;Azokpota, 2005). Fermentation of maize dough involving yeasts induced higher concentrations of compounds related to yeasts fermentation products such as alcohols and esters (Annan et al, 2003c). The fermentation of gowé with K. marxianus and P. anomala used singly led to a relatively higher concentration of alcohol.…”

Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu)

“…The absence and/or very low level of ethanol production in the L. plantarum strains and C. tropicalis mixed culture fermentation was indicative of the dominant activities of the LAB in the fermentation, as well as a contamination free process. The role of yeast in the flavour of fermented maize products has been reported by Annan et al (2003), Mugula et al (2003) and Omemu et al (2007). Therefore, the characteristic of C. tropicalis to grow in the fermentation, with little or no ethanol production, could be important in akamu production as the product flavour is an important sensory property.…”

“…The simple sugars are then converted to organic acids that create the acid environment which is known to improve product stability and safety. Although yeast's main function has been related to the production of alcohol and aroma compounds that impact significantly on food quality parameters such as taste, texture, odour and nutritive value (Aidoo, Nout, & Sarkar, 2006;Annan, Poll, Sefa-Dedeh, Plahar, & Jakobsen, 2003), Omemu et al (2007) reported that yeasts associated with maize fermentation for ogi production produced several extracellular enzymes and the amylolytic activities of some of the yeasts were implicated in the breakdown of maize starch to simple sugars for other fermenting microorganisms. Contamination of cereal-based complementary foods has been implicated in diarrhoeal episodes among infants and children <5 years in developing countries.…”