Development of yoghurt supplemented with selected herbs and analysis of its physico-chemical properties

With the emergence of fortified foods, there has been a worldwide increase in health awareness and interest in adding herbs as prized food additives in dairy and food products. However the effect of supplementation of dairy products with herbs on their physic-chemical properties is not well documented. This study was done to determine the effect of given amounts of herbal supplementation on the quality and shelf life of yoghurt. The specific objectives of the study were to establish the pH and titratable acidity of the yoghurt supplemented with selected herbs. The selected herbal extracts were Aloe vera (Aloe barbadensis Miller), Beetroot (Beta vulgaris), and Moringa (Moringa oleifera). Herbal yoghurts were developed with different concentrations; 1, 1.5, and 2% each of aloe vera, beetroot and moringa leaf extracts with plain yoghurt used as a control. Yoghurts were stored at 4 °C and their pH and titratable acidity tested on day 1 after incubation, and days 7, and 14 after production and stored at 4°C. The pH of all the samples of aloe vera and beetroot on average was found to decrease between day I to 14, with an increase in titratable acidity, possibly due to increase in microorganism activity and fermentation. This pH range is not only an indicator of good quality yoghurt, but that yoghurt supplemented with the two herbs possibly has more of the beneficial acids for human health as compared to ordinary yoghurt. However, moringa yoghurt at 1% concentration level had nearly the same pH and titratable acidity with plain yorghurt. Higher concentration levels of moringa at 1.5% and 2% were found to have relatively higher pH and less titratable acidity. Although suspected to be richer in minerals than plain yoghurt, its quality could not be guaranteed at that temperature.