Development and characterisation of Prunus nepalensis fruit-aquafaba probiotic powder by vacuum freeze drying

Usage of probiotics in plant-based matrices has increased due to the addition of functional foods to the human diet. This work subjected to produce powdered probiotic sohiong juice to add value to a fruit rich in bioactives. Lactobacillus plantarum subsp. lactis (MCC 2974) inoculated into sohiong juice with different concentrations of aquafaba as a cryoprotectant and freeze dried. The freeze dried samples were characterized for the viable cell count, physicochemical properties, storage properties, and morphological characterisation. A formulation (F3) that contains probiotic juice and aquafaba at a 1:0.3 (v/v) ratio exhibits improved physicochemical properties, including lower hygroscopicity (13.12 ± 0.39%), indicating lower moisture absorption. This is followed by a wettability measurement of 38.15 ± 0.36 s, which indicates the time taken to sink the powder sample in water; it also retained colour parameters. The aquafaba mixed formulation shows increasing loose bulk density and reduction in porosity. Hausner Ratio and Carr's Index value prove that the formulated F3 sample passes the scale of flowability as per United States Pharmacopeia standards. Field Emission Scanning Electron Microscopy (FESEM) images confirmed proper particle formation of probiotics, followed by Fourier Transform Infrared (FTIR) Spectroscopy, which proved that the aquafaba formulation doesn't lose functional groups that present in the probiotic juice. Thermogravimetric Analysis (TGA) (30% residue at 800 °C) and Differential Scanning Calorimetry (DSC) (18.995 J/g) analysis results showed that aquafaba improved the thermal stability of sohiong fruit juice. It shows the potential of combining underutilized fruits with plant-based stabilizers to develop sustainable, health-promoting nutraceuticals.