Functional herbal yoghourt with Moringa oleifera flower extract: RSM-based optimisation, and quality evaluation

Moringa oleifera has a greater nutritional value due to the different parts of this tree being used as rich sources of vitamins, minerals, and amino acids. At the same time, yoghourt is considered to have healthful properties because of its probiotic ability, helping to maintain the balance of gut microbiota. The aim of the present investigation is to assess the influence of the addition of M. oleifera flower extract on the fermentation behaviour and product quality of yoghourts made by standard yoghourt starter cultures, consisting of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. It was also done to study the physicochemical characteristics and storage stability of the enriched yoghourt. Incubation time and extract concentration were optimised using response surface methodology, based on multiple responses of titratable acidity, pH, protein, antioxidant activity, total phenolic content, and total flavonoid content. Sensory evaluation revealed that there is no significant difference in the enriched and control yoghourts in terms of appearance and texture, but the enriched yoghourt had a better flavour and overall acceptability.