J Nutritional Health Food Engg 2014, 1(2): 00012 Submit Manuscript | http://medcraveonline.com Journal of Nutritional Health & Food Engineering the sensorial attributes and also to decrease the properties of undesirable compounds in products. Lactic acid fermentation has been reported as a means to reduce beany flavours and anti- nutritional factors, such as phytic acid in soy beans [6]. Aside fermentation, effect of soaking in reducing the apparent beany/ nutty flavours of legumes have been studied [7]. In producing Soy-peanut-cow milk yoghurt, the study combined soaking of oilseeds in sodium bicarbonate solution, heat treatment and fermentation processes to further enhance the removal of undesirable components in oilseeds [8]. Functional properties of food proteins are essential factors to consider in food processing or in the formulation of new food products [9]. Proteins impart desirable functional properties like water holding capacities, viscosity, emulsification, gelatin, foam formation and whipping capacity to food systems [9,10]. The functionality of soy and peanut protein in food systems is influenced by intrinsic factors of the protein and the presence of other components in the food environment [10]. Water holding capacity is a term that is frequently employed to describe the ability of a matrix of molecules to physically entrap large amounts of water in a manner that inhibits exudation [11]. WHC of a protein gel is a vital consideration in yoghurt manufacturing, because it is related to syneresis, which is due to the intrinsic instability of gels resulting in loss of water after some storage time [12]. Syneresis is a quality defect frequently faced in yoghurt manufacture. Less syneresis had been found in yoghurts produced from a mixture of skim milk and soymilk regardless of the type of starter culture utilized [13]. The water holding capacity of peanut Introduction Yoghurt is a fermented milk product and has been noted to be the most widely consumed fermented dessert worldwide [1]. Traditionally, the product is prepared by fermenting cow milk with lactic acid bacteria Streptococcus thermophilus and Lactobacillus bulgaricus. Acidification of milk by lactic acid bacteria enhances the aggregation of milk proteins to form a yoghurt gel. When milk is fermented and in the process gets acidified, the internal structural properties of casein miscells are disrupted [2]. Acid induced milk gels are formed by the aggregation of casein particles as the pH of milk decreases and caseins approach their isoelectric point (pH 4.6) [3]. Milk-like beverages manufactured from legumes such as soya beans and peanut have also been noted as potential nutritional substitutes in cultures where cow milk is used [4,5]. Soy-peanut yoghurt is a composite fermented milk product developed by culturing milk extracts from soybeans and peanut with lactic acid producing bacteria. Since yoghurt is basically a protein gel formed as a result of the acidification of milk by starter bacteria mainly lactic acid bacteria, a strong soy protein- peanut protein- cow milk protein interaction could generate a stable milk gel. Yoghurt manufactured from a composite milk blend can offer a considerable appeal for a growing segment of consumers with certain dietary and health concern. The need to also exploit further sources of high quality food proteins and high energy foods has made it imperative to study the possibility of developing soy-peanut-cow milk yoghurt. Fermentation processes have been utilized to improve Abstract Acidification of milk by lactic acid bacteria enhances the aggregation of milk proteins to form yoghurt gels with enhanced texture, colour and viscosity. A three- component constrained mixture design was employed to develop 10 soy-peanut-cow milk (SPCM) formulations which were fermented with Lactobacillus bulgaricus and Streptococcus thermophilus (1:1) into soy-peanut-cow milk yoghurt (SPCY). The effect of ingredient variations on microbial acidification, colour, susceptibility to syneresis, water holding capacity and viscosity were determined. Titratable acidity increased with increasing cow milk content and trends in pH were contrary to titratable acidity. SPCY formulations were yellowish-white in colour. Yellowness and lightness increased with increasing soymilk content. Rheologically all products investigated were non-Newtonian and had better consistencies as cow milk content increased in samples and peanut milk content decreased. The water holding capacities of yoghurt samples increased with increasing soy milk content. Formulations without cow milk were the least susceptible to syneresis. Keywords Vegetable milk; Yoghurt; Starter culture; Viscosity; Susceptibility to syneresis; Souring Effect of Ingredient Variation on Microbial Acidification, Susceptibility to Syneresis, Water Holding Capacity and Viscosity of Soy-Peanut- Cow Milk Yoghurt Research Article Volume 1 Issue 2 - 2014 Fidelis Mawunyo Kwasi Kpodo, Emmanuel Ohene Afoakwa*, Betty Bediako Amoa, Agnes Simpson Budu and Firibu Kwesi Saalia Department of Nutrition & Food Science, University of Ghana, Ghana *Corresponding author: Emmanuel Ohene Afoakwa, Department of Nutrition & Food Science, University of Ghana, P. O. Box LG 134, Legon-Accra, Ghana, Tel: +233- 0-207366861; Email: eafoakwa@ug.edu.gh Received: April 29, 2014 | Published: May 24, 2014