e-ISSN:2321-6204 p-ISSN:2347-2359 RRJFDT | Volume 1 | Issue 2 | October-December, 2013 18 Research and Reviews: Journal of Food and Dairy Technology Suitability of Concentrated Milk for Yoghurt Preparation. Mallikarjun Chukki, K Jayaraj Rao*, BV Balasubramanyam, Bikash C Ghosh and S Kulkarni Dairy Technology Section, National Dairy Research Institute (Southern Campus), Adugodi, Bangalore – 560 030, Karnataka, India Research Article Received: 20/09/2013 Revised: 30/09/2013 Accepted: 02/10/2013 *For Correspondence Dairy Technology Section, National Dairy Research Institute (Southern Campus), Adugodi, Bangalore – 560 030, Karnataka, India Keywords: Yoghurt, vacuum concentration, toned milk, physico-chemical characteristics ABSTRACT Yoghurt was prepared from toned mixed milk (TS 11.5%) vacuum concentrated to 23% TS, using yoghurt culture ( mixed culture of S. thermophilus and L. bulgaricus) and its quality was evaluated by acidity, pH, penetrometer – hardness, wheying – off and sensory characteristics. The overall acceptability of yoghurt produced from concentrated milk was significantly low due to salty taste , very firm, leathery body and textural characteristics. Yoghurt produced from concentrated milk with 7.5% added sugar (sucrose) had less acidic taste and loose body and textural characteristics compared to control sample. However, the concentrated milk diluted to toned milk solids level, with and without added sugar yielded good quality yoghurt whose physico-chemical quality characteristics were comparable to those of toned milk yoghurt. INTRODUCTION Indian dairy industry is in a dynamic state with ever increasing market competition. Presently about 85 % of the milk procured by the dairies is utilized for market milk operations, which involves processing, packaging and transportation of liquid milk, bulk of which is constituted by water. This implies that most of the energy and money are spent for water which seems to be a redundant expenditure. Hence, it was proposed to reduce the water content of milk which could minimize wastage of energy and money in such operations. Further, this could aid in alleviating the environmental pollution problem, besides offering the consumer the convenience of having milk the composition of which can be altered as per the requirement. Moreover, the concentration of milk has the advantage of using the milk for production of various milk - based products. Yoghurt is one such product which is getting popularity particularly among urban consumers. The present study was therefore undertaken to assess the suitability of concentrated milk for the preparation of set yoghurt as it is gaining popularity with several entrepreneurs. MATERIALS AND METHODS Milk Cow and buffalo milk received from the Institute farm was used in all the trials after mixing in equal proportion (mixed milk). Standardisation The mixed milk was standardized to 3 % fat and 8.5 % SNF by using skimmed milk. Concentration Standardised milk after heat treatment at 75°C / 30 sec was concentrated by evaporation under vacuum (600 Hg) in a batch type vacuum evaporator (APV model) to half its volume so that the TS content was in the range of 23 %. Culture For the production of Yoghurt, the Visbyvac yoghurt - 709 culture (Germany) was used.