Licuri Kernel (Syagrus coronata (Martius) Beccari): A Promising Matrix for the Development of Fermented Plant-Based Kefir Beverages

Abstract

New licuri-based kefir beverages were obtained using water kefir grains as fermentation inoculum (1, 2.5, and 5%) under different fermentation times (24 and 48 h). Metagenomic sequencing of the kefir grains adapted to the aqueous licuri extract revealed Lactobacillus hilgardii and Brettanomyces bruxellensis to be predominant in this inoculum. The excellent adaptation of the kefir grains to the licuri extract raised the possibility of prebiotic action of these almonds. The beverages showed acidity values between 0.33 ± 0.00 and 0.88 ± 0.00 mg lactic acid/100 mL and pH between 3.52 ± 0.01 and 4.29 ± 0.04. The viability of lactic acid bacteria in the fermented beverages was equal to or greater than 10⁸ CFU/mL, while yeasts were between 10⁴ and 10⁵ CFU/mL. There were significant differences (p < 0.05) in the proximate composition of the formulations, especially in the protein (1.37 ± 0.33-2.16 ± 0.84) and carbohydrate (5.86 ± 0.19-11.51 ± 1.26) contents. In addition, all the samples showed good stability in terms of acidity, pH, and viability for LAB and yeasts during 28 days of storage (4 °C). Overall, the beverages showed a dominant yellow-green color, non-Newtonian pseudoplastic behavior, and high mean scores in the sensory evaluation. This study provided evidence of the emerging potential of licuri in the plant-based beverage industry.

Keywords: Lactobacillus; fermentation; kefir; metagenomics; non-dairy alternative.

Figure 1

Flowchart outlining the process of aqueous licuri extract preparation, kefir grains adaptation, and fermented plant-based kefir beverages development.

Figure 2

Viability of lactic acid bacteria (a) and yeasts (b) in plant-based fermented kefir beverages of licuri kernel stored for 28 days at 4 ± 2 °C. Different lowercase letters indicate significant differences (tukey p < 0.05) depending on the treatment used for the time evaluated. Different capital letters indicate significant differences (p < 0.05) between treatments over storage time. D0: The moment after the grains were removed; D7: After 7 days of storage; DT4: After 14 days of storage; D21: After 21 days of storage; T28: After 28 days of storage. (A) Fermented for 24 h with 1% inoculum; (B) Fermented for 48 h with 1% inoculum; (C) Fermented for 24 h with 2.5% inoculum; (D) Fermented for 48 h with 2.5% inoculum; (E) Fermented for 24 h with 5% inoculum; (F) Fermented for 48 h with 5% inoculum.

Figure 3

Rheological curve of fermented plant-based kefir beverages of licuri kernel. (a) Shear stress versus strain rate; (b) Viscosity versus strain rate; (aqueous extract) aqueous licuri extract; (A) fermented for 24 h with a 1% inoculum; (B) fermented for 48 h with a 1% inoculum; (C) fermented for 24 h with a 2.5% inoculum; (D) fermented for 48 h with a 2.5% inoculum; (E) fermented for 24 h with a 5% inoculum; (F) fermented for 48 h with a 5% inoculum.

Figure 4

Principal component analysis of parameters of fermented plant-based kefir beverages of licuri kernel. JAR: Mean score obtained on the near-ideal scale for perception of acidity and sweetness; (*) CIELAB system; LAB: lactic acid bacteria; WHC: water holding capacity; (A) fermented for 24 h with 1% inoculum; (B) fermented for 48 h with 1% inoculum; (C) fermented for 24 h with 2.5% inoculum; (D) fermented for 48 h with 2.5% inoculum; (E) fermented for 24 h with 5% inoculum; (F) fermented for 48 h with 5% inoculum.

Figure 5

Hierarchical cluster analysis of fermented plant-based kefir beverages of licuri kernel. (A) Fermented for 24 h with 1% inoculum; (B) fermented for 48 h with 1% inoculum; (C) fermented for 24 h with 2.5% inoculum; (D) fermented for 48 h with 2.5% inoculum; (E) fermented for 24 h with 5% inoculum; (F) fermented for 48 h with 5% inoculum. (C1) Cluster 1; (C2) Cluster 2; (C3) Cluster 3.