An evaluation of the potential of Inga paterno sarcotesta and its seeds for the production of probiotic beverages: their effect on antioxidants and Lactiplantibacillus plantarum viability at refrigeration storage temperatures

The sarcotesta and seeds of Inga paterno are good sources of nutrients but are rarely explored. Meanwhile, Lactiplantibacillus plantarum (LP) is widely used for probiotic beverage production. The aim of this work was to evaluate the flavonoid content, antioxidant stability, and L. plantarum viability in different formulations of the I. paterno beverage under refrigeration conditions.

The three beverages were prepared using I. paterno 5% w/v sarcotesta (Sa), 5% w/v seed (Se), or a 1:1 mixture of (Ae) and water. All were sterilized for LP inoculation (2.1×10⁶ CFU/ml), incubated (72h), and stored at 5°C. LP quantification was carried out in MRS agar (0, 4, 11, 18, and 25d). The total phenolic content (TPC) was determined by the Folin–Ciocalteu method, and antioxidant activity (TAC) was determined by DPPH•. Experiments were carried out in triplicate. Data were analyzed by one-way ANOVA and Tukey’s test (p < 0.05).

LP concentration increased in Se, Sa, and Ea (2.77×10⁷, 8.67×10⁶, and 3.97×10⁷ CFU/ml) compared to the initial amount. Microorganisms decreased in Ea every week until 8.67×10⁴ CFU/ml; however, microorganisms were stable in Se but decreased after 11d of storage (2.67×10⁴ CFU/ml). On the contrary, a slight increase was observed in Sa (2.10×10⁷ CFU/ml), which may be due to a greater presence of carbohydrates. Sa presented the highest TPC (69.54±9.13-376.42±7.07 ug gallic acid equivalents (GAE)/ml) and TAC (84.34±2.23-106.32±3.91 ug Trolox equivalents (TE)/ml). Se reaches the lowest TPC and TAC values (29.75±3.54-146.00±10.02 ug GAE/ml; 34.47±1.67-69.91±1.183 ug TE/ml, respectively). TPC and TAC presented the same tendency for Sa and Ea. The data showed that the sarcotesta of I. paterno was a better ingredient for the development of an antioxidant–probiotic beverage because it increases the antioxidant compounds and ensures the viability of LP. However, for the use of I. paterno, it is necessary to consider that it is a seasonal crop. Further investigations are needed to characterize the antioxidant compounds generated after fermentation.