*Corresponding author. Email: nayana@ansci.ruh.ac.lk eISSN: 2550-2166 / © 2022 The Authors. Published by Rynnye Lyan Resources FULL PAPER Food Research 6 (5) : 174 - 182 (October 2022) Journal homepage: https://www.myfoodresearch.com Effect of sugar replacement with stevia on quality of vanilla flavoured cow milk set yoghurt * Narayana, N.K., Govinda, G., Kumari, A.V. and Palliyaguru, O.G. Department of Animal Science, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, 81100, Sri Lanka Article history: Received: 22 July 2021 Received in revised form: 28 August 2021 Accepted: 19 December 2021 Available Online: 28 September 2022 Keywords: Calorie content, Stevia, Sugar replacement, Yoghurt DOI: https://doi.org/10.26656/fr.2017.6(5).548 Abstract Stevia extracted from the leaf of Stevia rebaudiana Bertoni plant is a natural alternative sweetener that has the potential to be used as a sugar replacer in sweetened dairy products. The current study aimed to investigate the effect of sugar replacement with stevia extract on the quality of vanilla flavoured cow milk set yoghurt. Cow milk was standardized to 3% fat and 12% milk solids non-fat. Commercially available pure stevia extract was used to replace the sugar (maintained at 8% in the control) at the rate of 0 (control), 25% (T1), 50% (T2), 75% (T3) and 100% (T4) in cow milk set yoghurt. Yoghurt mixtures were separately heat treated (85°C/30 mins), cooled to inoculation temperature (42°C), inoculated with commercial yoghurt culture containing Streptococcus thermophilus and Lactobacillus delbruekii subsp. bulgaricus (1:1 ratio) and incubated till the pH reaches nearly 4.6. Set yoghurt samples were tested for chemical composition, organoleptic attributes, physicochemical and physical properties using standard procedures. Total calorie content was calculated per 100 g of yoghurt. Milk fermentation characteristics, water holding capacity and instrumental colour of yoghurt were not affected ( p>0.05) by the sugar replacement with stevia. Carbohydrate content showed a decrease while protein and ash showed an increasing trend with an increasing level of sugar replacement in yoghurt. A 100% sugar replacement with stevia resulted in a 16.83% reduction in the calorie content of yoghurt. Control, as well as 100% sugar replaced yoghurt, obtained higher sensory scores while in the other treatments a decreasing trend in the sensory score was observed with the increasing level of sugar replacement suggesting possible interaction of stevia compounds with sucrose. It can be concluded that the replacement of 100% sugar is possible with the commercially available stevia extract used in the current study for the production of vanilla flavoured set yoghurt. 1. Introduction Yoghurt is considered a nutrient-dense healthy dairy product and therefore, it has a growing consumer demand throughout the world. It has been reported that the global yoghurt market reached a value of nearly US$ 40.6 billion in the year 2019 and is forecasted to reach approximately US$ 51.2 billion by 2024 (Shahbandeh, 2020). Yoghurt is marketed in various physical forms such as set, stirred, drinking, frozen and more, and in different types such as natural, fruit on the bottom, sweetened flavoured and sundae style. Yoghurt is a good source of protein, calcium, phosphorus, iodine vitamin B2, B12 like nutrients (Moore et al., 2018) and its consumption is associated with a lower risk of obesity and cardio-metabolic risk in children as well as in adults (Marette and Picard-Deland, 2014; Cormier et al., 2016). Sucrose is the main sweetener used in the production of sweetened yoghurt due mainly to the desirable sweet taste, easy availability and low cost (Giri et al., 2014). However, excessive consumption of sugar leads to various health ailments such as type II diabetes, obesity, cardiovascular diseases, tooth decay etc. (Cichosz et al., 2011; Kalicka et al., 2017). Even a small amount of sugar reduction can significantly improve the diet and the health of an individual (Mahato et al., 2020). Therefore, there is a growing interest in the food industry to use low/no-calorie alternatives for sugar. On the other hand, there is a big demand for ‘lite’ products among current health-conscious consumers (Narayanan et al., 2014). Therefore, low-calorie dairy products with alternative sweeteners have a promising market. Even though many alternative high-intensity