Ability of a Wild Weissella Strain to Modify Viscosity of Fermented Milk

Abstract

Despite the fact that strains belonging to Weissella species have not yet been approved for use as starter culture, recent toxicological studies open new perspectives on their potential employment. The aim of this study was to evaluate the ability of a wild Weissella minor (W4451) strain to modify milk viscosity compared to Lactobacillus delbrueckii subsp. bulgaricus, which is commonly used for this purpose in dairy products. To reach this goal, milk viscosity has been evaluated by means of two very different instruments: one rotational viscometer and the Ford cup. Moreover, water holding capacity was evaluated. W4451, previously isolated from sourdough, was able to acidify milk, to produce polysaccharides in situ and thus improve milk viscosity. The ability of W4451 to produce at the same time lactic acid and high amounts of polysaccharides makes it a good candidate to improve the composition of starters for dairy products. Ford cup turned out to be a simple method to measure fermented milk viscosity by small-or medium-sized dairies.

Selection of Exopolysaccharide-Producing Lactobacillus Plantarum (Lactiplantibacillus Plantarum) Isolated from Algerian Fermented Foods for the Manufacture of Skim-Milk Fermented Products

“…At low shear rate, the apparent viscosity decreased when increasing the shear rate in all cases (Figure 4). This flow is a typical shear-thinning and non-Newtonian behaviour, characteristic of pseudoplastic fluids, as reported by several authors for milks fermented with EPS-producing and non-producing LAB [61,62]. At higher shear rates, the viscosity decreased and remained without noticeable changes, then behaving as a Newtonian fluid [63].…”

Interaction of the Exopolysaccharide from Lactobacillus plantarum YW11 with Casein and Bioactivities of the Polymer Complex

“…As shown in Table 1 , increasing the addition of EPS-YW11 from 0.25% to 1% ( w / v ) resulted in decreased hardness, adhesiveness and increased viscosity of the EPS-YW11/CAS complex samples, but cohesion of the samples were not obviously affected ( p > 0.05). This might be due to increased interactions of EPS with CAS when more EPS was added, leading to less hard and adhesive samples [ 35 , 36 , 37 ]. Previously, Zhang et al [ 38 ] reported that EPS could affect the textural properties of a yogurt clot by decreasing its hardness.…”

Lactic Acid Bacteria Exopolysaccharides Producers: A Sustainable Tool for Functional Foods

“…In certain cases, heat treatment is used to improve the EPS recovery from the culture medium as the first step in EPS isolation [ 27 , 32 , 35 , 58 , 97 , 98 ]. For the following precipitation of EPS, ethanol is commonly used [ 27 , 42 , 43 , 50 , 55 , 58 , 99 ], although isopropanol [ 100 ], acetone [ 33 ] or a mixture of acetone and ethanol [ 101 ] have been also used.…”

“…Finally, the EPS is lyophilized [ 27 , 33 , 35 , 43 , 99 , 101 ] to remove moisture and allow long storage. For molecular characterization purposes, additional purification steps have been employed to increase the purity of the EPS fraction, by applying advanced instrumental techniques such as size-exclusion chromatography (SEC) or ion-exchange chromatography [ 8 , 27 , 36 , 44 , 47 , 53 , 99 ].…”

“…A colorimetric procedure for the determination of total carbohydrate (expressed as glucose equivalents per unit of weight) by phenol-sulfuric acid method is the most widely used method of calculating EPS yield [ 27 , 33 , 34 , 42 , 43 , 44 , 49 , 55 , 99 , 102 ]. A similar colorimetric technique is the anthrone-sulfuric acid method reported by some researchers as another useful method for the quantification of carbohydrates [ 101 , 103 , 104 ].…”