Abstract The increasing interest in functional foods has encouraged the search for new lactic acid bacteria (LAB) with singular characteristics, including technological and probiotic properties, present in natural sources. The present research aimed to isolate and in vitro characterize the probiotic potential of LAB isolated from artisanal goat cheese. In addition, the acidifying and proteolytic capacity of the strains were evaluated in order to develop a functional dairy product. Fifty strains, presumptively identified as LAB, were isolated from artisanal goat cheese. From them, seventeen strains were selected for identification through Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry (MS) and 16S gene sequence. None of the tested strains showed hemolytic ability, while all strains showed at least 76% of survival to low pH and conjugated bile salts. Hydrophobicity and auto-aggregation values varied among LAB with ranges between 15.5 ± 1.8 to 84.7 ± 3.2, and 4.72% to 59.2%, respectively. Selected LAB were capable of adhering to intestinal mucus in a range of 5.08 to 6.90 Log CFU/mL. Remarkably, eight strains showed high bile salt hydrolase activity. Autochthons strains were able to grow and acidify milk after 24 h. Besides, proteolytic activity showed a range between 10 and 151 mmol/L amino acids. PCA analysis and technological properties allow us to propose Lactiplantibacillus plantarum CB5, CB8 and Lentilactobacillus parabuchneri CB12 strains as potential probiotic starter cultures. The isolation of new LAB strains with demonstrated functional properties is of interest to academic institutions and the food industry as it allows the design of indigenous dairy cultures with added probiotic and technological properties.

Resumo O crescente interesse por alimentos funcionais tem incentivado a busca por novas bactérias láticas com características singulares, incluindo propriedades tecnológicas e probióticas, presentes em fontes naturais. A presente pesquisa teve como objetivo isolar in vitro e caracterizar o potencial probiótico de BAL isoladas de queijo artesanal de leite de cabra. Além disso, as capacidades acidificante e proteolítica das cepas foram avaliadas a fim de desenvolver um produto lácteo funcional. Cinquenta cepas, presumivelmente identificadas como BAL, foram isoladas de queijo de leite de cabra artesanal. Destas, 17 linhagens foram selecionadas para identificação por Espectrometria de Massa MALDI-TOF e sequência do gene 16S. Nenhuma das cepas testadas apresentou capacidade hemolítica, enquanto todas as cepas apresentaram pelo menos 76% de sobrevivência a pH baixo e sais biliares conjugados. Os valores de hidrofobicidade e autoagregação variaram entre LAB com faixas de 15,5 ± 1,8 a 84,7 ± 3,2, e 4,72% a 59,2%, respectivamente. Todas as bactérias láticas selecionadas foram capazes de aderir ao muco intestinal na faixa de 5,08 a 6,90 Log UFC/mL. Notavelmente, oito cepas mostraram alta atividade de hidrolase de sais biliares. Cepas autóctones foram capazes de crescer e acidificar o leite após 24 h. Além disso, verificou-se atividade proteolítica mostrando uma faixa entre 10 e 151 mmol/L de aminoácidos. A análise de PCA e as propriedades tecnológicas permitem propor cepas de Lactiplantibacillus plantarum CB5 e CB8, e Lentilactobacillus parabuchneri CB12 como culturas iniciais probióticas. O isolamento de novas cepas de bactérias láticas com propriedades funcionais demonstradas é de interesse para instituições acadêmicas e para a indústria alimentícia, pois permite o desenho de culturas lácteas nativas com potenciais propriedades probióticas e tecnológicas agregadas.

Ochratoxin A (OTA) is a mycotoxin produced by filamentous fungi with high impact Lactic acid bacteria; in food safety due to its toxicity. In the last decade, the presence of OTA was widely reported in different foods. In this study, the ability of Lactobacillus (L.) plantarum CRL 778 to control growth and OTA production by Aspergillus (A.) niger 13D strain, at different water activity (a w) values (0.955, 0.964, 0.971, 0.982, and 0.995) was determined in vitro. Both parame ters were significantly (p<0.05) reduced by the lactobacilli and the effect depended on a w. Greatest growth rate inhibition (46.9%) was obtained at a w = 0.995, which is the most suitable value for growth and production of antifungal metabolites (lactic acid, acetic acid, phenyllac-tic and hydroxyl-phenyllactic acids) by L. plantarum CRL 778. Besides, morphological changes and inhibition of melanin synthesis were observed in colonies of A. niger 13D in presence of L. plantarum CRL 778 at a w ranged between 0.971 and 0.995. In addition, maximum reduction (90%) of OTA production took place at a w = 0.971, while inhibition of fungi growth was more evident at a w =0.995. These findings suggest that L. plantarum CRL 778 could be used for control of ochratoxigenic fungal growth and OTA contamination in different fermented foods with a w values between 0.971 and 0.995.

Ocratoxina A (OTA) es una micotoxina producida por hongos filamentosos con un alto impacto en la seguridad alimentaria debido a su toxicidad. En la última década se ha reportado ampliamente a nivel mundial, la presencia de OTA en diversos alimentos. En este estudio se evaluó in vitro, la capacidad de Lactobacillus (L.) plantarum CRL 778 de controlar el crecimiento y la producción de OTA por Aspergillus (A.) niger 13D, a diferentes valores de actividad de agua (a w): 0.955, 0.964, 0.971,0.982 y 0.995). La cepa láctica redujo significativamente (p <0.05) ambos parámetros, siendo el efecto dependiente del valor de a w. La mayor inhibición del crecimiento (46.9%) se obtuvo a a w =0.995, valor más adecuado para el crecimiento y producción de metabolitos antifúngicos (ácido láctico, ácido acético, ácidos fenil-láctico e hidroxi-fenil láctico) por la cepa láctica. Además, se observaron cambios morfológicos en las colonias de A. niger 13D, crecidas en presencia de L. plantarum CRL 778 a valores de a w de 0.971 y 0.995. El porcentaje máximo de reducción en la producción de OTA (90%) por la cepa láctica se observó a un valor de a w = 0.971, mientras la inhibición del crecimiento fúngico fue mayor cuando a w = 0.995. Estos hallazgos sugieren que L. plantarum CRL 778 podría emplearse para el control de la contaminación por hongos ocratoxigénicos en alimentos con valores de aw comprendidos entre 0.971-0.995.