West African sorghum beer fermented with Lactobacillus delbrueckii and Saccharomyces cerevisiae: shelf-life and consumer acceptance

Abstract

The fermentation profiles, shelf‐life and consumer acceptance of traditional West African sour sorghum beer (pito) fermented with pure commercial starter cultures of lactic acid bacteria (L. delbrueckii) and yeast (Saccharomyces cerevisiae) were evaluated. The beers from this ‘pure culture’ approach were compared with the spontaneous fermentation of pito wort. Lactic acid formation, pH change and extract utilisation were monitored during fermentation. Lactic acid content was used as a measure of sourness to establish the spoilage level of over‐sourness. Further, regression models relating sourness to the time the drink was kept were used to predict the shelf‐life. Consumer acceptance of the product was evaluated using a novel nine‐point hedonic scale. The pure culture and traditionally fermented beers followed similar lactic acid and fermentation profiles but strain‐specific differences were observed. Similar levels of pH, lactic acid level and extract utilisation were achieved. An improvement in shelf‐life of two days was found over traditionally fermented pito. There was no statistical difference between the two pito products for overall liking and taste. However, there was a preference for the aroma of the pure culture pito. It is suggested that the use of pure cultures will facilitate the scale‐up of pito production. © 2019 The Institute of Brewing & Distilling

Potential Application of Tetrapleura tetraptera and Hibiscus sabdariffa (Malvaceae) in Designing Highly Flavoured and Bioactive Pito with Functional Properties

“…The inclusion of extracts or whole prekese and HS (boiled in wort) could lead to a drop in the pH of wort due to the overwhelming phytochemicals present, hence it should be adjusted with buffers, such as calcium carbonate and calcium sulfate/calcium chloride, before pitching. The pH of the final pito documented by [164] is similar to the values reported earlier. A pocket-sized handheld pH meter is the ultimate easier method that local brewers could adopt in measuring the pH of the mash, wort, and final beer.…”

“…Sensory evaluation of pito brewed with a pure yeast culture and dembila revealed that the panellists found no difference in their overall liking between the two products; however, the pure culture enhanced the flavour. The authors concluded that the pure starter culture could be utilized to facilitate scaled-up pito production [164]. Lyumugabe et al [166] reported that hopping wort with V. amygdalina leaves resulted in the synthesis of polyfunctional thiols; however, it inhibited the production of 2-sulfanylethanol and 2-sulfanylethyl acetate.…”

“…However, the chemical method is not ideal due to flavour alteration, toxicity, cost, and availability of these chemicals to local brewers. Djameh et al [164] recently reported that brewing pito with pure culture (L. delbrueckii and S. cerevisiae) extended the shelf life up to 3 days compared to pito brewed with dembila. However, due to the rapid synthesis of lactic acid, the product became undrinkable after 5 days of production.…”

Microorganisms and food safety risks associated with indigenous fermented foods from Africa

“…delbrueckii and Sacch. cerevisiae (Djameh et al, 2019). However, this may not be a sustainable solution due to cost implications.…”

Brewing with Unmalted and Malted Sorghum: Influence on Beer Quality

“…Research to date has focused on optimizing the sorghum brewing process and obtaining a finished product with sensory characteristics that meet consumer acceptability [2]. The studies carried out focused on the possibility of using sorghum as an adjuvant to obtain beer, either in ground or extruded form in a proportion of 40-60% compared to barley malt [2,3,17,18] or used in beer manufacturing at 100% sorghum malt [13,[18][19][20]. The presence of sorghum beers on the market is recognition of the possibility of using this grain in brewing.…”