Extending the shelf life of locally brewed beer (Malwa) using bitter leaf extract (Vernonia Amygdalina)

Abstract

Increasing agricultural production and value addition through careful use of appropriate technologies is necessary to ensure food security and combat hunger and malnutrition. Through alcoholic fermentation, local beverages such as Malwa are made from cereals in developing countries. Malwa production basically comprises malting, mashing, filtration, boiling, fermentation, and maturation. However, due to poor hygiene, low ethanol levels, varying organoleptic characteristics and poor maintenance, Malwa seem less attractive, unstable and generally has a short shelf life. Therefore, it is necessary to employ technologies that will improve its nutritional and marketable qualities. Chemical additives are generally undesirable in food preservation. Also, the use of pasteurization seems limiting in Malwa production. However, phytogenic-based extracts of V. amygdalina are considered safe, ecofriendly and not prone to severe microbial resistance. They contain bioactive compounds that may impair the activities of unwanted microorganisms and ultimately extend the shelf life of Malwa. This research focuses on the role of V. amygdalina in the shelf life of Malwa. Freshly brewed malwa was treated with a cold-water extract of bitter leaf and then stored at temperature regimes of 10⁰C and 30⁰C.Both the control and real experiments were stored at this temperature. The pH, ABV, TSS and TA of freshly brewed malwa was determined and on the third day of storage the same parameters were determined. On the forth day of storage, Lactobacillus bacteria were enumerated. The samples with the bitter leaf extract had colonies within the acceptable range according to ISO standards as compared to the ones without bitter leaf extract. They also had a better alcohol level and the pH, TA was also within the acceptable range for normal beers. On analyzing the data using one way ANOVA, it was found that the bitter leaf extract had extended the shelf life of Malwa. It was thus concluded that V. amygdalina had extended the shelf life of Malwa since it was still safe for consumption on the third and fourth day. However, further studies are required in order to find the compounds which mainly determine the acceptability or rejection of the product and determine the sensory attributes. So, a better preservation strategy could be proposed