Bifidus milk powder: processing parameter standardization and shelf stability evaluation.

Spray dried bifidus milk powder was prepared by supplementing cow milk with different level of additives to obtain slurry of desired concentration. The slurry was pasteurized, cooled and inoculated with Bifidobacterium bifidum, incubated and dried to produce a bifidus milk powder. Among the various bifidus milk powder prepared, the slurry of mention the level total soluble solids exhibited good organoleptic characteristics and it has been standardized for further analysis. Moisture content, bulk density, insolubility index, hydroxymethyl furfural and thiobarbituric acid value of bifidus milk powder significantly increased, while the reflectance value significantly decreased during storage. The B. bifidum count significantly reduced and the bacterium were not detected at the end of the mention storage duration. As such the sentence is not acceptable in the abstract. The reconstituted bifidus milk powder was considered acceptable with an overall acceptability score of 6.97 on a nine-point Hedonic scale and showed a shelf stability of 120 days at ambient temperature condition (27 ± 2 °C).

Optimization of seabuckthorn fruit yogurt formulation using response surface methodology.

The response surface methodology was used to optimize the formulation of seabuckthorn fruit yogurt. The independent variables were proportions of seabuckthorn fruit syrup and skimmed milk powder. The responses were counts of Streptococcus thermophilus and Lactobacillus bulgaricus, taste and viscosity of the product. Statistical analysis revealed that fruit syrup and skimmed milk powder significantly affected all the responses. Contour plots for each response were used to generate an optimum area by superimposition. Optimum formulation conditions of fruit syrup (15 %) and skimmed milk powder (12.5 %) are recommended for the blend formulation yielding an acceptable and good quality seabuckthorn fruit yogurt. Model validation was conducted using separate experiments at optimum conditions. The experimental values were found to be in close agreement to the predicted values and were within the acceptable limits indicating the suitability of the model in predicting quality attributes of seabuckthorn fruit yogurt. The resultant product also exhibited more amounts of fat, protein, carbohydrate and antioxidants viz., vitamin C, E, carotenoids, phenols and anthocyanins when compared to a commercial one.

Optimization of spray drying process for developing seabuckthorn fruit juice powder using response surface methodology.

The response surface methodology was used to optimize the spray drying process for development of seabuckthorn fruit juice powder. The independent variables were different levels of inlet air temperature and maltodextrin concentration. The responses were moisture, solubility, dispersibility, vitamin C and overall color difference value. Statistical analysis revealed that independent variables significantly affected all the responses. The Inlet air temperature showed maximum influence on moisture and vitamin C content, while the maltodextrin concentration showed similar influence on solubility, dispersibility and overall color difference value. Contour plots for each response were used to generate an optimum area by superimposition. The seabuckthorn fruit juice powder was developed using the derived optimum processing conditions to check the validity of the second order polynomial model. The experimental values were found to be in close agreement to the predicted values and were within the acceptable limits indicating the suitability of the model in predicting quality attributes of seabuckthorn fruit juice powder. The recommended optimum spray drying conditions for drying 100 g fruit juice slurry were inlet air temperature and maltodextrin concentration of 162.5 °C and 25 g, respectively. The spray dried juice powder contains higher amounts of antioxidants viz., vitamin C, vitamin E, total carotenoids, total anthocyanins and total phenols when compared to commercial fruit juice powders and they are also found to be free flowing without any physical alterations such as caking, stickiness, collapse and crystallization by exhibiting greater glass transition temperature.