Valorization of guava residues: evaluation of substrates and nutritional potential in seed germination

Abstract

Guava seeds, a byproduct of guava (Psidium guajava L.) industrialization, stand out for their high protein content compared to the pulp, which can be further enhanced through germination. In this study, two substrates were evaluated: cotton (CN) and a mixture of peat moss, vermiculite, and perlite (PVP). Under controlled conditions at 30 °C for 30 days, parameters such as sprout height (h), root/shoot ratio, germination speed index (GSI), germination percentage (GP), biomass weight (P), and protein content (PC) were measured. The average height of the sprouts was 5.57 ± 0.15 cm in AL and 5.03 ± 0.15 cm in PVP. The root/shoot ratio varied, with values of 0.52 ± 0.43 for AL and 0.44 ± 0.11 for PVP. GSI was higher in AL with 2.5 ± 0.87 seeds/day, compared to PVP with 1.3 ± 0.4 seeds/day. However, the GP % at the end of the evaluation period was similar in both substrates, at 40 % and 39 % for AL and PVP, respectively. The protein content of the sprouts at the end of the evaluation showed no significant differences (10.39 % ± 0.34 and 11.06 % ± 1.57 for PVP and AL, respectively). Both substrates proved suitable for germination, and the increase in protein content suggests the potential use of these byproducts in both animal and human nutrition.