Effect Of Soya Protein On Chemical And Sensory Characteristics Of Permented Milk Product
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Publisher: 2009 Dissertation note: Increased population, high cost and changing consumer attitude towards animals based proteins has put greater pressure for the consumption of proteins from plant origin. Soya bean contains almost 40% high quality protein which can be used as a source of proteins in various products. There was a need to develop convenience foods with high energy, good nutritional status and extended shelf life from indigenous resources. Thus the present research project was designed to asses the feasibility of incorporating soya protein isolate to improve nutritional quality of kurut and to determine the physico-chemical properties of SPI-fortified kurut with 90 days of storage. For the reason, yoghurt was converted into long life product (Kurut) with the addition of soya protein isolate (SF1) @ 10%, 15%, 20% and 25%, whereas kurut prepared without the addition of SF1 was taken as control.
Storage has influential significant effect on moisture content of the kurut samples; increased from 11.25c to 12.36a% with 90 days of storage period. Moisture content differed non-significantly with the addition of SF1 in Kurut and ranged from 11.57 to 11.86%. Protein content was momentously affected as a function of SF1 augmentation and non-significantly affected with storage and treatment-storage interaction. All the five treatments showed significant differences for the crude protein content of the product (Kurut).The protein content increased progressively with the addition of SPI in Kurut and the significantly highest protein content was noted in T4 (57.85a%), followed by T3 (55.30b%) and T2 (52.70c%) while the lowest crude protein content was found in To (44.77e%).
The means values of fat content of soya protein isolate fermented dairy product differed momentously and To contained the highest value (9.62a %) followed by 8.94b and 8.59c% in T1 (10% SF1) and T2 (15% SPI), respectively. The lowest value (8.Ole %) for the fat content was found in T4, which was prepared from 25% SPI addition in Kurut recipe. The means for the crude fiber content of SF1 enriched Kurut exhibited that T4 (SPI 25%) had the highest significant crude fiber (0.31a %) followed by 0.2Th% in T3 (SPI 20%) 0.23b% in T2 and T1 whereas, lowest fiber value was recorded for control Kurut (0.21b %). The ash content decreased significantly at all levels of SPI addition in the product; decreased from 9.97a% to 7.61e% up to 25% of soya protein isolate addition. The overall range for the NFE content was found to be from 25.89±1.00 to 35.60±1.04%.
Lactose content ranged from 19.90% to 26.90% from beginning to end of the study. Minimum mean value for lactose (22.77%) was observed at 0 day where as increasing trend was observed with progressive increase of storage period. The highest total solids were noted in T3 (88.43a) followed by T4 (88.42a) and T2 (88.38 a), whereas the lowest total solids value was found in case of To also it is controlled treatment i.e. (88.14a) (Table 4.9). The mean values for total solids of different treatments with 90 days of storage are mentioned in Table 4.9 all the treatments different momentously for total solids were noted 88.75a, 88.45a, 88.45a, 87.64a at 0 , 30, 60 and 90 days respectively.
The means value for acidity of various treatments showed in Table 4.10. It ranged from 1.52d to 1.81a % from initiation to end of the study. Minimum mean value for acidity (1.49d %) was observed at 0 day where as increasing tendency was observed with progressive increase of storage period. At 30 days, it was 1.57c % that increased to 1.67b % at 60 days and 1.79a at 90 days. The mean pH values of all the treatments decreased momentously with storage interval. The highest pH value was noted in T4 (4.53a) followed by T3 (4.38b), T2 (4.16c), and Ti (4.Old), whereas the lowest pH value was found in case of T0.
Color scores assigned to control Kurut were highest (12.Ola), which differed non-significantly with scores assigned to 10% SPI fortification (12.18a), 15% SF1 fortification (12.02a) and 20% SPI fortification (11.88a) while scores given to 25% SPI fortification (11.llb) were significantly lowest from all other treatment scores. Storage has significant effect on color of SF1 fortified Kurut. The scores for flavor of Kurut prepared from different SPI fortified samples showed that Kurut prepared from control obtained the highest flavor score (12.35a) followed by T1 and T2 that were assigned 12.22a and 11.78b scores, respectively. The significant lowest flavor scores 9.Old was allocated to T4 (25% SPI). Storage resulted significant effect on flavor of Kurut prepared from different SPI levels. At 0 day, the highest flavor score (11.62 a) was given by the panelists which decreased to 11.18b, 10.72c and 10.25d after 30, 60 and 90 days of storage.
Texture scores differed variably with SPI addition level whereas, decreased with the progression of storage period. Average overall scores for texture ranged from 10.2± 0.88 to 13.6± 1.34 among various treatments throughout the storage period. It is obvious from the findings that panelists rated higher with SPI addition up to 15% (T2).The judges placed T1 (12.47a) at the top for overall acceptability scores which differed non-significantly with control Kurut (12.28ab) followed by T2 (12.03b) T3 (10.07c) while the lowest mean overall acceptability scores were assigned to T4 (9.19d). Storage also has significant negative effect on overall acceptability scores; decreased from 11.80a at the start of the study to 11.41b, 10.92c , and 10.71c at 30, 60 and 90 days of storage interval, respectively.
Generally, soya protein isolate addition in Kurut (fermented dairy product) resulted in improved chemical and nutritional value. SF1 addition resulted in progressive increase in protein and fiber content, whereas fat and ash contents decreased with SPI augmentation. Regarding sensoric acceptability of Kurut prepared with SF1 fortification; organoleptic quality was affected with SPI levels, however, Kurut prepared from up to 15% SF1 level was not much different from control Kurut. Hence Kurut prepare up to 15% SPI addition level with improved nutritional profile, increased level of essential amino acids and acceptable organoleptic quality has a potential to cope protein deficiency in some vulnerable segment of population and is thus recommended for commercial application.
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