Development and biochemical characterization of freeze-dried guava powder fortified with Lactobacillus plantarum

Guava (Psidium guajava L.) is one of the most nutrient-dense fruits, which is native to tropical and subtropical regions of the world. The processing of value-added products from guava has not been carried out on a scale similar to some other fruits, which offers an opportunity to fully exploit the potential of this fruit, such as guava-based nutraceutical food products. The objectives of the present study were to develop freeze-dried guava powders (FDGPs) from two guava varieties (white and pink) and characterize their physico-chemical and nutritional properties. FDGP was also incorporated with probiotic strains of Lactobacillus plantarum, to develop a healthy nutraceutical probiotic supplement. Functional groups assessed by Fourier transform infrared (FTIR) spectroscopy exhibited the existence of strong C-Br stretch, O-H stretch, and C = C stretch vibrations; however, scanning electron micrograms (SEMs) showed the flaky structure indicating the presence of starch, dietary fibers, and esterified groups of pectin. Significant mineral concentrations (mg/100 g) of potassi-um (323-362), magnesium (26.2-28.8), zinc (0.43-0.51), and iron (0.52-0.63) were observed in FDGPs. The FDGP samples from both guava varieties had high levels of crude fiber (43.94-46.29%), vitamin C (2.27-2.49 mg/g), and phenolic compounds (57.50-61.86 mg GAE/g) as well as significant antioxidant properties. Fortification of FDGP with L. plantarum strains produced significant results in terms of probiotic viability that was nearly maintained at 10⁸ CFU/g up to 60 days in the final product. The viability of probiotics proved that FDGP is a good carrier of prebiotics and can be utilized as a potent probiotic supplement.