Changes in the Folate Content and Fatty Acid Profile in Fermented Milk Produced with Different Starter Cultures during Storage

Abstract

The application of bacterial cultures in food fermentation is a novel strategy to increase the “natural” levels of bioactive compounds. The unique ability of lactic acid bacteria (LAB) to produce folate, B vitamins, and conjugated linolenic acid cis9trans11 C18:2 (CLA) during cold storage up to 21 days was studied. Although some species of LAB can produce folates and other important nutrients, little is known about the production ability of yogurt starter cultures. Pasteurized milk samples were inoculated with four different combinations of commercially available yogurt vaccines, including starter cultures of Bifidobacterium bifidum. Both the type of vaccine and the time of storage at 8 °C had a significant effect on the folate and CLA contents in the tested fermented milks. The highest folate content (105.4 µg/kg) was found in fresh fermented milk inoculated with Lactobacillus delbrueckii, Streptococcus thermophilus, and Bifidobacterium bifidum. Only the mix of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and Bifidobacterium bifidum showed potential (59% increase) to synthesize folate during seven days of storage. A significant increase in the content of CLA, when compared to fresh fermented milk, was observed during cold storage for up to 21 days in products enriched with Bifidobacterium bifidum.

Fatty Acid Content, Lipid Quality Indices, and Mineral Composition of Cow Milk and Yogurts Produced with Different Starter Cultures Enriched with Bifidobacterium bifidum

“…The contents of all the previously mentioned milk constituents, such as fatty acids and minerals, may differ from their contents in dairy products. Research results indicate that these differences may be due to various factors used in the technological process, such as heat treatment, homogenization or pasteurization, standardization [26][27][28][29][30], fermentation, starter culture type, fermentation time, and storage time and conditions [31][32][33][34][35][36]. High nutritional value of yogurts and other fermented milk drinks is highly influenced by the quality of milk and the production process used, as well as the possible increase in their bioavailability due to the fermentation process.…”

Folate-producing bifidobacteria: metabolism, genetics, and relevance

“…Folate content in a particular bacterium is not a static property unless conditions are steady, such as in a chemostat, which is never the case in real-life scenarios. Moreover, another significant factor is that the folate content can change significantly based on various factors, such as the type and degree of cellular activity, population state, growth rate, pH, temperature, and medium composition [ 77 - 79 ] . For example, folate-producing LAB strains exhibited a temperature-dependent pattern.…”

“…Some studies investigated the ability of bifidobacteria to increase folate content directly in fermented milk, indicating their potential use in obtaining fermented dairy products [ 77 , 101 , 102 ] . Thirty-two Bifidobacterium isolates ( B. lactis spp., B. animalis spp., B. infantis spp., B. breve spp.)…”

Lactococcus lactis in Dairy Fermentation—Health-Promoting and Probiotic Properties

“…The hyl gene encodes an enzyme called hyaluronidase and the presence of the hyl gene can contribute to virulence and the ability of the bacterium to spread within host tissues [86]. The aggregation substance coded by the asa1 gene is enterococcal surface protein and it often acts as a virulence factor and it transfers antibiotic resistance genes [85,87]. The cell wall adhesin (efa A) is a virulence factor associated with infective endocarditis [86].…”

“…Folate is generated from the precursors, such as guanosine triphosphate, para-amino benzoic acid, and glutamate, which act as building blocks for the production of various folate derivatives such as tetrahydrofolate, 5-formyl tetrahydrofolate, 5,10-methenyl tetrahydrofolate, 10-formyl tetrahydrofolate, and 5,10-methylene tetrahydrofolate in a number of enzymatic steps. Also, among various LAB, L. lactis is the only organism known to possess a complete biosynthesis route for folate [87,283,284]. L. lactis genes, menF, menA, preA, and mvk, are responsible for vitamin K2 (menaquinone) production.…”