To establish an ultra performance liquid chromatography (UPLC) analysis method that can simultaneously determine niacin, niacinamide, and vitamin B6 in formula milk powder. Gradient elution was performed with 10 mmol/L ammonium acetate solution (containing 0.1% formic acid) as mobile phase A and methanol as mobile phase B. The analytes were separated by Poroshell 120 EC-C18 in tandem with ACQUITY? UPLC HSS T3 column, detected with the UV detector and fluorescence detector, and quantified by an external standard method. Good linearity was observed for niacin concentrations in the range of 0.0-0.8 μg/mL，nicotinamide concentrations in the range of 0.0-20.0 μg/mL, pyridoxamine concentrations in the range of 0.0-0.2 μg/mL, pyridoxal concentrations in the range of 0.0-0.6 μg/mL and pyridoxine concentrations in the range of 0.0-4.0 μg/mL, and the correlation coefficients of standard curves were all greater than 0.999. The limits of detection and quantification met the requirements. The average recoveries of the method were all in the range of 80.5%-104.1% with relative standard deviation (RSD) were 0.37%-2.99%. This method is simple, accurate, can be used for batch detection of niacin, niacinamide, and vitamin B6 in formula milk powder.

The fermentation conditions for producing a fermented dairy beverage from skim milk added with the polysaccharide extract from Dendrobium officinale were optimized in the present study. Beverage with the best flavor was obtained when skim milk added with 50% Dendrobium officinale polysaccharide and sugar at levels of 10% and 7% (by mass), respectively was fermented at 42 ℃ for 6 h after inoculation with the starter culture (Lactobacillus bulgaricus:Streptococcus thermophilus = 1: 1) at a level of 0.10%.