| dc.description.abstract | Yogurt is widely known for its nutraceutical properties. Beans are a healthy and easily affordable food containing good amount of raffinose that has been proven to possess prebiotic properties. Recent research shows that consuming oligosaccharides is possibly the best way to balance gut microflora. Raffinose Family Oligosaccharides (RFOs) is the most commonly found sugar belonging to this group and is mostly contained in pulses. However, studies on yogurt and beanraffinose are limited. The goal of this research was to isolate and characterize raffinose oligosaccharide from soybeans and demonstrate practical utility of raffinose oligosaccharide by studying its effect on the quality of yogurt. Raffinose powder was prepared from soybeans using the methods of soaking, incubation and freeze drying. In this study, 2% low-fat milk was supplemented with 1% and 2% (w/v) Soy-RFO, inoculated with starter culture, Streptococcus thermophiles and L. delbrueckii subsp. Bulgaricus, fermented and stored at 4 ºC. The fortified yogurts were studied for changes in physiochemical (pH, titrable acidity, color, syneresis, viscosity, water activity, total soluble solids, water holding capacity), fermentation, antioxidant, texture profile and microbiological properties. These changes were compared with the properties of 1% (w/v) Inulin fortified yogurt and plain yogurt as the control. Results demonstrated that RFOs enhanced the growth and viability of probiotics present in yogurt. The fermentation rate of RFO yogurt was higher when compared to Plain or Inulin yogurt; 1% (w/v) RFO fermented the milk in 4 hours, which was 1 hour and 1.5 hours lesser than the time taken by Inulin and plain yogurt respectively. A significant (p<0.05) decrease in pH and increase in total titrable acidity was observed during the 21-day storage study with 2% (w/v) RFO-yogurt having the least pH and highest titrable acidity. Total soluble solids were found to be the highest in 2% (w/v) RFO yogurt which gradually decreased throughout the storage period. 1% (w/v) Inulin yogurt had a higher content of soluble solids when compared to the 1% (w/v) RFO yogurt, which proves that RFO was more preferred for consumption by the probiotics. Syneresis was found to be the highest in plain yogurt followed by 1% (w/v) RFO yogurt, then 1% (w/v) Inulin yogurt and least in 2% (w/v) RFO yogurt. This explains the least amount of water holding capacity by plain yogurt and highest by 2% (w/v) RFO yogurt. Though the difference is not very high, by 2% (w/v) RFO yogurt had the highest viscosity with plain yogurt being the least viscous when compared to the other samples. Water activity of all the 4 samples were at a desired level through the 21-day storage period. There were no significant changes in the color between the 4 yogurt samples and it remained the same during storage as well with not much changes. 2% (w/v) RFO yogurt exhibited greatest antioxidant activity and this can be attributed to the increased microbial growth. Addition of Soy-RFO improves the firmness of yogurt and this increase in turn also increases the chewiness of Soy-RFO yogurt. These observed results clearly suggest that raffinose oligosaccharide enhances the overall quality of yogurt, thereby offering a probiotic yogurt with prebiotics, which can also be called a symbiotic yogurt. Basic changes made to the physical and technological parameters of yogurt dairy food products like yogurt is gaining significant interest resulting in the development of new products. Based on this study we can say that the Raffinose oligosaccharide powder extracted from soybeans is an ingredient that is promising from a view of new product development and fortification. In addition to all the benefits, this natural ingredient gains attention due to its health benefitting properties, and this makes it easy for the consumers to adopt them as a practice. | en_US |
