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The purpose of this paper is to optimize the environmental growth factors for maximum yield of biomass and protein content of Spirulina platensis var lonor.

Central composite design with four independent variables (namely, Temperature (°C), Light intensity (μmol m⁻² s⁻¹), incubation period (days) and inoculum concentration (per cent)) and two dependent variables (namely, Biomass yield (g/L) and Protein content (per cent)) were used for designing the experiment. The quadratic model was selected for analysis of data using analysis of variance and optimization was performed using response surface methodology (RSM). Central Food Technological Research Institute (CFTRI) medium was used for growing the organisms.

The predicted values of optimization showed that the maximum yield of dried biomass (1.13 g/L) and protein (57.45 per cent) were obtained at temperature of 33.6°C, light intensity of 67.50 μmol m⁻² s⁻¹, incubation period of 16 days and inoculum concentration of 20 per cent. The actual values of biomass (1.23 g/L) and protein (58.46 per cent) yield were almost similar to the predicted responses.

The data obtained with this optimization method help Spirulina researchers/producers to cultivate the S. platensis var lonor strain with maximum biomass and protein content using the CFTRI medium.

Earlier works on optimization of growth conditions for Spirulina biomass, revealed that maximum of two factors were employed at a time using factorial design. But unlike other studies here in this study, optimization of multi factors using at a time using RSM on better biomass and protein yield was employed.

Radish (Raphanus sativus) is valued for its nutritive and medicinal properties, but its juice is not palatable because of the pungent flavor. The purpose of this study is to optimize the blending process of radish juice by using sugarcane juice, herbal extract and salt concentration.

The statistical design provided 20 formulations; where herbal extract concentration varied from 0.5 to 2.5 per cent, sugarcane juice concentration from 20 to 50 per cent and salt concentration from 0 to 1.5 per cent.

The p = 0.05 was used to designate the statistical significance of all the responses under study. Different product formulations had total soluble solids (TSS) that ranged from 9.7 to 15.0°Brix, titratable acidity from 0.6 to 1.3%, pH from 3.3 to 4.0, reducing sugars from 0.6 to 0.8%, total sugars from 9.4 to 3.1%, total protein from 172.9 to 304.8 mg/100 ml, total phenols from 25.5 to 29.8 mg/100 ml, ascorbic acid from 10.4 to 19.8 mg/100 ml, antioxidant activity from 77.3 to 83.6% and overall acceptability from 5.6 to 7.7. Sugarcane juice concentration of 30%, herbal extract mixture and salt concentrations of 1 and 1.5%, respectively, were the optimized process conditions for the preparation of nutritional radish juice achieved with the best fit of desirability, i.e. 0.88. Cluster analysis revealed that concentration of sugarcane juice had the maximum significant effect on the quality characteristics of nutritional radish beverage as compared to the other two variables under study.

The developed product can help to promote the use of radish as a substrate for the beverage industry.

Soy beverage is becoming more and more popular because it is touted as a healthy food containing useful phytochemicals and is free from lactose and cholesterol. The purpose of this paper is to optimize the spray drying process parameters for obtaining soy beverage powder with good reconstitution and handling properties.

Pre-concentrated soy beverage was dried in a laboratory model spray dryer, and the effects of inlet air temperature (180-220°C), feed rate (20-40 ml/min) and feed solid content (15-25 per cent) on some physical parameters and reconstitution properties (wettability and dispersibility) of spray-dried soy beverage powders were investigated. Second order polynomial response surface model was selected for the analysis of data and optimization of the process.

Spray drying of soy beverage at different processing conditions resulted in powders with particle size (volume mean diameter) in the range of 86 to 156 µm. Dispersibility and wetting time of the spray-dried soy beverage powders was found to be in the range of 56 to 78 per cent and 30 to 90 s respectively, under various drying conditions. Inlet air temperature was found to be the main factor affecting most of the quality parameters, followed by solid content of the feed. Temperature significantly affected the wettability, dispersibility, colour parameters, particle size and flowability of the powder at p ≤ 0.01. Lower temperature and higher feed solid content produced bigger-sized powder particles with better handling properties in terms of flowability and cohesiveness. A moderate inlet air temperature (196°C), higher feed solid content (24 per cent) and lower feed rate (27 ml/min) were found suitable for drying of soy beverage.

The study implied the possibility of producing powder from soy beverage using the spray-drying method and optimized drying conditions for obtaining soy beverage powder with good reconstitution properties.

The finding of this study demonstrated for the first time how the inlet air temperature, feed solid content and feed rate during spray-drying influenced different quality parameters of soy beverage powder. Further, an optimized drying condition has been identified.