The Effect of Starter Culture Addition on Cow’s Milk and Plant-Based Milk Bases in Yoghurt Production

Abstract

Yoghurt is a fermented product resulting from the activity of lactic acid bacteria and is recognized as a functional food with probiotic benefits. Conventionally, yoghurt is made from cow's milk; however, the growing demand for plant-based products has encouraged the development of soy milk-based yoghurt as a lactose-free alternative. Differences in substrate composition between cow's milk and plant-based milk affect starter culture performance and the quality of the resulting yoghurt. This literature review aims to analyze and compare the effect of starter culture addition on the microbiological, physicochemical, sensory, and functional characteristics of cow's milk-based and plant-based yoghurts, particularly soy milk. The method used was a literature study of accredited national journal articles published between 2015 and 2025 that discussed yoghurt fermentation using lactic acid bacteria and/or probiotics. The results show that cow's milk yoghurt has better gel stability, moderate viscosity, relatively stable pH, and consistent lactic acid production owing to the presence of lactose and casein. In contrast, plant-based yoghurt shows higher viscosity, protein content, and bioactive compounds such as isoflavones, but is more sensitive to variations in starter concentration, potentially causing excessive acidity and syneresis. The type and concentration of the starter culture and the fermentation conditions play an important role in determining yoghurt quality on both bases. Therefore, optimization of the starter culture and fermentation parameters is required to produce high-quality yoghurt, especially in plant-based formulations, in order to achieve a balance between probiotic viability, functional value, and consumer acceptance.