Microbiological, chemical and sensory characteristics of Masa produced from different cereals in Ghana

Abstract

Masa is a traditional sour puff pastry dough made from fermented millet, rice or maize dough which is fried in a pan with individual cuplike depression. Its popularity is limited to the northern parts of Ghana but is available throughout the country. This work was carried out to assess the effect of using the different cereals in masa production on the microbial species which dominate masa fermentation and also its effect on the organoleptic quality of the masa produced. A survey was carried out in parts of Accra where masa is very well known and produced. Both producers and consumers were interviewed using structured questionnaire and samples collected for laboratory analysis. The microbiota during fermentation was examined on MRS agar and OGYEA for Lactic Acid Bacteria (LAB) and yeasts respectively. The LAB and Yeast were tentatively identified by determining their pattern of carbohydrate fermentation using the API kit and Bruker MALDI Biotyper Mass Spectrometry which is based on the analysis of protein spectrum from microbial ribosome, which is closely related to the analysis of the 16S rRNA gene sequence. The proximate composition of the three different types of masa were analyzed which involved the determination of the moisture, ash, fat, protein, carbohydrate and energy contents. The organoleptic quality of the three different types of masa was also evaluated by a 40-member sensory panel by affective testing using a 9 - point Hedonic scale. The survey confirmed that masa is made from millet, rice or a combination of maize and rice and that the procedure differed based on the cereal or cereals used. The LAB species isolated were identified as Pediococcus acidilactici (37%), Lactobacillus plantarum (25%), Lactobacillus fermentum (23%) and Lactobacillus brevis (15%). The yeasts species isolated were Candida krusei (45%), Pichia farinose (35%), and Candida tropicalis (20%). All LAB isolates exhibited antimicrobial activity against E. coli, Vibrio cholera, Staphylococcus aureus and Salmonella typhimurium with L. fermentum exhibiting the strongest inhibition against Staphylococcus aureus, Vibrio cholera and Salmonella typhimurium. The results show the different proximate composition of the three different types of masa. The results of the sensory panel were in agreement with the results of the consumer survey which showed that the majority of masa consumers preferred maize-rice masa to the other types of masa