Abstract:
Several health benefits of Moringa oleifera commonly known as ‘drum-stick’ tree have been researched and documented. As a result of this, Moringa oleifera leaves extract incorporation and fortification has been carried out in foods such as yoghurt to generate a functional food that advances human health and prosperity. However, information on its utilization especially in yoghurt and its effects in micronutrients during fermentation remains scanty. The main objective of this study was to establish the effect of Moringa oleifera leaves extract on the utilization of iron and manganese by starter cultures during yoghurt development. The resultant rheological properties of the developed yoghurt and the resultant total Lactobacillus and Streptococcus counts which constitute the yoghurt starter culture as well as morphological characteristics were also explored. To achieve this, Moringa oleifera leaves extract of varying concentrations were added in milk during yoghurt development. Total manganese and iron were later determined spectrophotometrically, rheological properties were recorded taking into account the firmness, cohesiveness and consistency and lastly cell culture and gram staining was used to establish cell morphology.
The results showed that cocci shaped Streptococcus thermophilus counts increased significantly with increase in the Moringa oleifera leaves extract concentration while Lactobacillus bulgaricus growth was inhibited by Moringa oleifera leaves extract. The firmness and consistency of yoghurt decreased significantly with increase in Moringa oleifera leaves extract concentration while cohesiveness increased slightly during yoghurt development.
Keywords:
Moringa oleifera leaves extract, Yoghurt, Streptococcus, Lactobacillus, Iron, Manganese, Rheology.