Effect of vegetable by-products on folate production by starter and probiotic microorganisms to develop a bio-enriched fermented soy product

• Autor(a) principal: Albuquerque, Marcela Albuquerque Cavalcanti de
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/9/9133/tde-05092018-105229/
• topic: Anti-inflammatory activity; Atividade anti-inflamatória; Bioaccessibility; Bioacessibilidade; Compostos fenólicos; Fermented soy product; Folate; Folato; Fruit by-product; Phenolic compounds; Prebiotic; Prebiótico; Probióticos; Produto fermentado de soja; Subprodutos de fruta; `Probiotic

This study aimed to evaluate the effect of vegetable by-products, including fruit by-products (passion fruit, orange, acerola, and mango) and soy by-product (okara), on the folate production by starter and probiotic strains for the bio-enrichment of fermented soy products. In the first part of this study, the impact of amaranth flour on folate production by these microorganisms was also evaluated. The effect of vegetable by-products and amaranth flour on the ability of three starters - Streptococcus thermophilus (ST-M6, TH-4, and TA-40) and ten probiotic strains (Lactobacillus (Lb.) acidophilus LA-5, Lb. fermentum PCC, Lb. reuteri RC-14, Lb. paracasei subsp. paracasei Lb. casei 431, Lb. paracasei subsp. paracasei F19, Lb. rhamnosus GR-1, and Lb. rhamnosus LGG, Bifidobacterium (B.) animalis subsp. lactis BB-12, B. longum subsp. longum BB-46, and B. longum subsp. infantis BB-02) to produce folate was evaluated, using a modified MRS broth. Most of the microorganisms were able to produce folate. However, folate production was strain-dependent and also dependent on the environmental conditions and on the vegetable substrate used. Passion fruit by-product presented the lowest folate concentration and was selected for the following experiments. Thus, the impact of the supplementation of soymilk with passion fruit by-product and/or commercial prebiotic fructooligosaccharides FOS P95 on the folate production by three St. thermophilus strains, as well as four probiotic Lactobacillus strains (LA-5, LGG, PCC, and RC-14) were evaluated. St. thermophilus ST-M6 and TH-4 produced the highest amounts of folate in all fermented soymilks. The concentration of the vitamin was also high when these strains grew in co-culture with LA-5 and LGG. Soymilk supplemented with both passion fruit by-product and FOS together presented the highest concentration of folate when fermented by the co-culture TH-4+LGG. This co-culture was selected to produce four fermented soy products (FSP). All FSP were bio-enriched with folate produced by the co-culture and the probiotic strain LGG remained always above 8 log CFU/mL until the end of the storage period (28 days at 4ºC). In contrast, the concentration of the vitamin was stable until day 14 then a slight decrease was observed at the end of the storage period. The FSP supplemented with both passion fruit by-product and FOS together may contribute with around 14% of the recommended daily intake for folate if consumed until day 14 of storage. During the in vitro simulated gastrointestinal conditions, the folate content of the digested FSP increased from 1.3 to 3.6-fold, especially at the small and large intestinal in vitro phases and the strain LGG was recovered. In contrast, St. thermophilus TH-4 was not recovered during the assay. Finally, the prebiotic potential of the bioactive compounds present in the fruit by-products was characterized. Fruit by-product water extracts (FWE) containing soluble fibres from fruit by-products were obtained through a hot-water extraction and were associated to phenolic compounds and showed antioxidant activity. The FWE (especially, orange and mango water extracts) presented an anti-inflammatory potential by decreasing the nitric oxide concentration produced in vitro by macrophages stimulated with lipopolisaccharides (LPS) from Salmonella Thyphymurium. The FWE (especially from mango) were able to stimulate the growth of the strains TH-4 and LGG, as well the folate production by these microorganisms when tested individually and in co-culture. The FWE also increased the adhesion of TH-4 and LGG to Caco-2 cells in an in vitro model. These results suggest a prebiotic potential of the fruit by-products evaluated and their potential towards increased folate production by the selected microorganisms. Therefore, the bio-enrichment of fermented soy products with folate produced by beneficial microorganisms is an alternative for the development of functional foods with high folate content. Additionally, fermentable bioactive compounds with functional and/or biological activity, such as soluble fibres associated to phenolic compounds with antioxidant activity, present in the fruit by-products, may act as potential prebiotic ingredients. These bioactive molecules may represent a potential natural alternative to synthetic drugs for the treatment of inflammatory processes.