EVALUATION OF SELECTED TECHNOLOGICAL PARAMETERS FOR MANUFACTURE OF LASSI
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Date
1992
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AAU, Anand
Abstract
The present study was planned and conducted to evaluate certain technological parameters of Lassi manufacture. The experiment vms divided into three phases. In the first phase, preliminary trials were conducted to screen various starters used for dahi making and LBW + MD2 (1:1) at the rate of 2 per cent was found to give a good quality curd. This was followed by selection of optimum level of acidity in curd used for dahi making (levels 1.0, 1.2 and 1.4 per cent L.A.), level of TMS (6.5, 8.5 and 10.5 per cent), and sugar (8, 10 and 12 per cent) in Lassi. For preparing Lassi, curd was stirred, mixed with sugar syrup, heated at 65°C for 15 min, homogenized at 100 kg/cm2 and cooled to 10°C. From 27 combinations tried, Lassi made from curd having 1.2 per cent L.A., containing 10.5 per cent TMS and 10 per cent sugar was preferred the most. During second phase, selection of type and concent ration of stabilizer , added to Lassi before thermal processing, for impiovinc body-texture characteristics was attempted. From the stabilizers evaluated Viz., CMC (0.1 and 0.2 per cent), sodium alginate and guar gum (both at 0.05 per cent), guar gum (0.05 per cent) was found to bring about significant improvement in the sensoric quality of Lassi followed by sodium alginate (0.05 per cent), both were statistically at par. The stabilizers did not signifi cantly affect the flavour of Lassi. The higher levels employed were found to affect body-texture score adversely. The preference order was observed as guar gum (0.05 per cent) > sodium alginate (0.05 per cent) >sodium alginate (0,1 per cent) >guar gum (O.l per cent) >control >CMC (O.l percent) >CMC (0.2 percent ) . Viscosity of Lassi in the range of 50-60 cp was preferred. Though, CMC provided viscosity in this range, the product was found to score l e s s than the control mainly because of slight coarse t e x t u r e . The difference between the scores of Lassi made with CMC and control was statistically indistinguishable. In the third phase, heat treatment of Lassi for 15 min at 65°C (L65) and 70°C (L70) were attempted with a view to improve itshelf - life; up stream homogenization was followed during this study. The control (homogenized at 60°C and cooled immediately), L65 and L70 were stored at 37 + 2°C and 7 + 1°C till their spoilage. During storage, a marginal increase in acidity and decrease in pH were observed. The FFA content also tend to increase during storage. Both of these changes were found to proceed faster at the higher temperature of storage. The soluble nitrooen content also increased during storage, but the increase was found t o proceed at a faster rate at lower temperature of storage, which may be attributed to the enzymes elaborated by surviving obligatory psychrotrophs in Lassi. All the chemical changes were restricted by the thermal treatments employed and were minimum in L70. Thermal treatment caused reduction in lactic count of control, L65 and L70 by 1.00, 4.06 and 4.44 log cycle respectively.
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Keywords
DAIRY TECHNOLOGY, EVALUATION