No abstract

Abstractβ‐(2,1)‐linked fructan of plant origin (inulin) and the related oligosaccharides (FOS) as non‐digestible carbohydrates, i.e., potent prebiotics, can stimulate the growth of various probiotic lactic acid bacteria, including a number of bifidobacteria strains. The related β‐(2,6)‐linked fructans of microbial origin (levan and FOS), however, have scarcely been investigated in this respect. Therefore, the bifidogenic properties of various fructans, i.e., inulin, levan, fructooligosaccharides (FOS) and fructan syrup (FS), were tested as glucose substitutes in MRS media and were compared concerning their effect on the commercial strain Bifidobacterium lactis Bb 12. Although glucose was the preferred substrate for growth and biomass formation, FS exhibited a comparable cell growth (8.4 × 107 counts/mL and 1.0 × 107 counts/mL, respectively) and acidification power (84 °T and 74 °T, respectively) during 48 h of fermentation, as well as an increase in lactic acid and decrease in acetic acid formation. Bifidobacterium lactis Bb 12 did not utilize inulin as a sole carbon source as judged from the 60 % decrease in cell count and the insignificant (0.1 pH unit) acidification of the growth medium, whereas levan provided a noticeable increase in cell count and acidification (0.4 pH units) during 48 h of fermentation. FOS preparation appeared to be a satisfactory carbon source for this strain, but lower acidification power (56 °T) and cell counts were observed as compared to glucose‐ or FOS‐containing media (2.6 % and 22 %, respectively). The products obtained under conditions of mild lactic acid hydrolysis of levan (37 °C, pH 3.3, 24 h) enhanced the cell count (7–10 %) and acidification power (by a factor of 2.7) of Bifidobacterium lactis Bb 12.

Fish is a well-known source of proteins, minerals, fat-soluble vitamins, antioxidants and other bio-active ingredients. Fish and its processing by-products are relatively cheap raw materials however still rarely are used to create food products with increased nutritive value, functional foods or feed supplements. Application of certain strains of probiotic bifidobacteria for fermentation of non-dairy substrates is a great challenge for industry-targeted research and industry with further offering to the market of functional food products. Our study is the first report on application of bifidobacteria for fermentation of fish. It was shown that a new fish-based functional food product can be obtained after fermentation of Baltic herring mince, supplemented with carbohydrates and NaCl, with a single-strain probiotic culture Bifidobacterium animalis subsp. lactis Bb12. Evaluation of FT-IR spectroscopy data indicated changes of proteins and the composition of total carbohydrates in fermented Baltic herring samples compared to the control. Glucose and sucrose ensured quick acidification and the decrease of pH, to achieve the cell count of B. lactis Bb12 up to 10 8 CFU gG 1 , thus meeting requirements of the viable cell-count of probiotic bacteria in functional food products. However the highest cell counts of probiotic bacteria and acidification were reached using fish mince supplemented with sucrose (2%) and NaCl (1%). The obtained fermented baltic herring paste or its concentrate-after freeze-drying, still with high content of viable probiotic cells (10 7 -10 8 CFU gG 1 ), can be used as functional food product as well as food and feed ingredients.

No abstract

No abstract