Amaranth 11S globulins (Ah11Sn) are an excellent source of essential amino acids; however, there have been no investigations on the characterization of their techno-functional properties at different pH conditions and NaCl concentrations, which are necessary for food formulations. In this work, we report a new two-step purification method for native Ah11Sn with purity levels of ~95%. LC–MS/MS analysis revealed the presence of three different Ah11Sn paralogs named Ah11SB, A11SC, and Ah11SHMW, and their structures were predicted with Alphafold2. We carried out an experimental evaluation of Ah11Sn surface hydrophobicity, solubility, emulsifying properties, and assembly capacity to provide an alternative application of these proteins in food formulations. Ah11Sn showed good surface hydrophobicity, solubility, and emulsifying properties at pH values of 2 and 3. However, the emulsions became unstable at 60 min. The assembly capacity of Ah11Sn evaluated by DLS analysis showed mainly the trimeric assembly (~150–170 kDa). This information is beneficial to exploit and utilize Ah11Sn rationally in food systems.

Background: Curvularia eragrostidis is the causal agent of pineapple leaf spot disease. The search for biological control agents against C. eragrostidis is an activity of agricultural interest. Objectives: To evaluate the antagonistic capacity of Trichoderma spp. on C. eragrostidis and to determine the H2O2, laccase, chitinase and β-glucanase activities. Method: A strain of C. eragrostidis and six strains of Trichoderma spp. (T-82, T-84, T-85, T-94, T-98, T-99) were co-cultured. Interaction types were determined. Laccase activity, H2O2 and total protein in an enzymatic extract from the confrontation were determined spectrophotometrically. Qualitative chitinase and β-glucanase activities in C. eragrostidis and Trichoderma sp. T-98 were measured. Results and conclusions: Trichoderma sp. T-98 inhibited C. eragrostidis by 61.0% with a “partial replacement after a distant inhibition” type of interaction. C. eragrostidis produced laccase (0.027 U/mg of protein) and H2O2 (0.33 mg/L), which increased when it was confronted with Trichoderma sp. T-94 (Laccase=0.219 U/mg of protein) and Trichoderma sp. T-98 (H2O2=6.47 mg/L), respectively. Trichoderma sp. T-98 produced chitinases and β-glucanase, while C. eragrostidis only produced chitinases. The increase in H2O2 and laccase is associated with the defense of C. eragrostidis against Trichoderma spp. Antecedentes: Curvularia eragrostidis es el agente causal de la mancha foliar en piña. La búsqueda de agentes de control biológico contra C. eragrostidis es una actividad de interés agrícola. Objetivos: Evaluar la capacidad antagónica de Trichoderma spp. sobre C. eragrostidis y determinar la presencia de H2O2, lacasa, quitinasa y β-glucanasa. Método: Se confrontaron una cepa de C. eragrostidis y seis cepas de Trichoderma spp. (T-82, T-84, T-85, T-94, T-98, T-99). Se determinaron los tipos de interacción. Espectrofotométricamente se determinó la actividad lacasa, H2O2 y proteína total en el extracto enzimático de la confrontación. Se cuantificó cualitativamente la actividad quitinasa y β-glucanasa de C. eragrostidis y de Trichoderma sp. T-98. Resultados y conclusiones: Trichoderma sp. T-98 inhibió a C. eragrostidis en un 61% con un tipo de interacción “reemplazo parcial después de una inhibición a distancia”. C. eragrostidis produjo lacasa (0.027 U/mg de proteína) y H2O2 (0.33 mg/L), los cuales incrementaron cuando se confrontó con Trichoderma sp. T-94 (Lacasa=0.219 U/mg de proteína) y Trichoderma sp. T-98 (H2O2=6.47 mg/L), respectivamente. Trichoderma sp. T-98 produjo quitinasas y β-glucanasa, mientas que C. eragrostidis solo produjo quitinasas. El incremento de H2O2 y lacasa se asocia a la defensa de C. eragrostidis contra Trichoderma spp.