Technological and sensory properties of a fruit-based fermented beverage using selenized lactic acid bacteria

CRESPO, LAURA; SEDE LUCENA, BRENDA; DELLA FONTANA, FRANCO ; GOLDNER, MARÍA CRISTINA; MOZZI, FERNANDA; PESCUMA, MICAELA

Congreso; XVIII Congreso Argentino de Ciencia y Tecnología de Alimentos; 2023

Selenium (Se) is an essential micronutrient that plays a crucial role in human health; however, Se intake by most people is below the recommended daily intake (RDI). The aim of this work was to develop a Se-enriched fermented beverage using lactic acid bacteria (LAB) capable of converting inorganic Se into organic and more bioavailable forms. A pasteurized beverage based on mango and passion fruit pulps (1:1) diluted with sterile tap water (30% v/v) and adjusted to pH 5.6 was formulated. Individual cultures and a mixed culture of selenized or non-selenized cells of Fructobacillus tropaeoli CRL 2034 and Lactiplantibacillus paraplantarum CRL 2051 were used for fermentation. Bacterial growth, acidifying capacity, sugar consumption, and organic acid and mannitol production were evaluated. Also, the effect of selenization of the mixed culture against the harsh in vitro gastrointestinal (GIT) conditions was determined. Finally, a Sensory Focus Group (qualitative method) with 8 trained panelists analyzed the sensorial properties of the beverages and selected the attributes to be evaluated by further consumers (105 people between 18 and53 years old). F. tropaeoli CRL 2034 and L. paraplantarum CRL 2051 grew 1.91 ± 0.19 log CFU/ml after fermentation at 30 °C for 24 h increasing the acidity of the juices by 1.14 ± 0.21. Carbohydrates present in non-inoculated pasteurized mango-passion fruit juice were sucrose (32.83± 4.08 g/L), glucose (5.94 ± 0.63 g/L), and fructose (6.00 ± 0.63 g/L). L. paraplantarum CRL 2051 showed homofermentative behavior producing only lactic acid (5.12 ± 0.01 g/L). Selenized cells of F. tropaeoli CRL 2034 showed an increase of 0.50 ± 0.29 g/L of acetic acid compared to the control cells, while no difference in the production of lactic acid (2.58 ± 0.73) was observed. Mannitol production was detected in the juices fermented with Fructobacillus strain and with the mixed culture (6.94 ± 0.23 and 5.38 ± 0.00 g/L respectively), while no differences were observed between selenized and control cells. The total Se concentration determined by ICP-MS of the fermented juices with selenized cells increased between 36-40% with respect to the non-fermented juice. The selenized mixed culture was resistant to the acidic conditions of the simulated in vitro GIT system showing final cell counts of 8.29 ± 0.06 log CFU/mL (7.91 ± 0.14 F. tropaeoli CRL 2034, and 8.04 ± 0.01 L. paraplantarum CRL 2051). Scanning electron microscopy microphotographs showed rough membranes in both LAB after the GIT passage, and the presence of Se-nanoparticles before and after the treatment. The Focus Group determined that the fermented samples had a deep yellow-orange color with brightness, intense passion fruit odor, more acidic, and less sweet than the control. The fermented samples were accepted for their texture and color (6.28-7.38). The acidity was indifferent while fermentation had a negative effect on the smell, taste, and sweetness of the juice (p < 0.05). A fermented fruit drink with acceptable texture and color was achieved and more interestingly, 200 mL of this drink contained 40% of the RDI, according to the Argentinean CODEX.