Numerous health benefits have been reported from the consumption of cranberry-derived products, and recent studies have identified bioactive polysaccharides and oligosaccharides from cranberry pomace. This study aimed to further characterize xyloglucan and pectic oligosaccharide structures from pectinase-treated cranberry pomace and measure the growth and short-chain fatty acid production of 86 Lactobacillus strains using a cranberry oligosaccharide fraction as the carbon source. In addition to arabino-xyloglucan structures, cranberry oligosaccharides included pectic rhamnogalacturonan I which was methyl-esterified, acetylated and contained arabino-galacto-oligosaccharide side chains and a 4,5-unsaturated function at the non-reducing end. When grown on cranberry oligosaccharides, ten Lactobacillus strains reached a final culture density (ΔOD) ≥ 0.50 after 24 h incubation at 32 °C, which was comparable to L. plantarum ATCC BAA 793. All strains produced lactic, acetic, and propionic acids, and all but three strains produced butyric acid. This study demonstrated that the ability to metabolize cranberry oligosaccharides is Lactobacillus strain specific, with some strains having the potential to be probiotics, and for the first time showed these ten strains were capable of growth on this carbon source. The novel cranberry pectic and arabino-xyloglucan oligosaccharide structures reported here combined with the Lactobacillus strains that can metabolize cranberry oligosaccharides and produce short-chain fatty acids, have excellent potential as health-promoting synbiotics.

The relationship between Kombucha fermentation process parameters and microbial composition was investigated. Green tea Kombucha fermented slower, producing a higher sugar/acid ratio, residual sucrose, and sweeter taste compared to black tea Kombucha. No known probiotic bacteria were identified in Kombucha since Zygosaccharomyces, Brettanomyces, Komagataeibacter, and Gluconacetobacter were the dominant genera observed based on 16s rRNA sequencing analysis. Green tea epigallocatechin and epigallocatechin gallate inhibited bacterial growth in black tea Kombucha broth in a concentration-dependent manner. Green tea Kombucha produced from a 10-day inoculum had a higher sugar/acid ratio, residual sucrose, acetic acid, gluconic acid, and a pleasant flavor compared to a 15-day inoculum. In blended green and black tea Kombucha, a solid bacterial pellicle 9-day inoculum increased the amounts of glucose, fructose, acetic acid, gluconic acid, and ethanol, yet there was a lower sugar/acid ratio and residual sucrose, but no change in the catechin profile, compared to a completely liquid inoculum. Increasing the surface area/volume ratio to 0.16 during Kombucha production increased levels of glucose, fructose, and gluconic acid, while acetic acid and ethanol levels remained the same by favoring aerobic vs. anaerobic fermentation. These Kombucha fermentation process parameter results will help producers devise strategies for better quality control.

Consumers' growing interest in fermented dairy foods necessitates research on a wide array of lactic acid bacterial strains to be explored and used. This study aimed to investigate the differences in the proteolytic capacity of Lactobacillus helveticus strains B1929 and ATCC 15009 on the fermentation of commercial ultra pasteurized (UHT) skim milk and reconstituted nonfat dried milk powder (at a comparable protein concentration, 4%). The antihypertensive properties of the fermented milk, measured by angiotensin-I-converting enzyme inhibitory (ACE-I) activity, were compared. The B1929 strain lowered the pH of the milk to 4.13 & PLUSMN; 0.09 at 37 & DEG;C after 24 h, whereas ATCC 15009 needed 48 h to drop the pH to 4.70 & PLUSMN; 0.18 at 37 & DEG;C. Two soluble protein fractions, one (CFS1) obtained after fermentation (acidic conditions) and the other (CFS2) after the neutralization (pH 6.70) of the pellet from CFS1 separation, were analyzed for D-/l-lactic acid production, protein concentration, the degree of protein hydrolysis, and ACE-I activity. The CFS1 fractions, dominated by whey proteins, demonstrated a greater degree of protein hydrolysis (7.9%) than CFS2. On the other hand, CFS2, mainly casein proteins, showed a higher level of ACE-I activity (33.8%) than CFS1. Significant differences were also found in the D-and l-lactic acid produced by the UHT milk between the 2 strains. These results attest that milk casein proteins possessed more detectable ACE-I activity than whey fractions, even without a measurable degree of hydrolysis. Findings from this study suggest that careful consideration must be given when selecting the bacterial strain and milk substrate for fermentation.

β-galactosidase (B-gal) is a vital enzyme used in the food industry to reduce lactose from dairy ingredients through hydrolysis and to synthesize galacto-oligosaccharides (GOS), a known bifidogenic prebiotic, from galactose moieties through transgalactosylation. To favor transgalactosylation, high carbohydrate concentrations must be available to accept the galactose moiety. Since many dairy products rely on sweeteners for flavor and texture, B-gal from GRAS status Lactobacillus bulgaricus strains LB11, YB1, L. helveticus B548, or Kluyveromyces lactis (KL) in the commercial product Lactozyme® 2600L were used to determine if transgalactosylation can be driven in reconstituted nonfat dry milk (NDM, 10%, wt/wt) with commercial sweeteners compared with unsweetened NDM at 50°C for 18 h. Sucrose (14.4%, wt/wt), corn syrup solids (14.4%, wt/wt), or a mixture of sucrose (9.9%, wt/wt) and corn syrup solids (4.5%, wt/wt) were dissolved with NDM (n = 3), then heated with stirring for 30 min at 70°C for batch pasteurization. For Lactobacillus strains, whole cells were inoculated at 7 log cfu/mL, or the same quantity of cells were lysed before adding to the milk and carbohydrate mixtures, or 1.85 U of KL B-gal was used. The sucrose mixture released the highest glucose from all B-gal preparations, with LB11 lysate releasing the highest (245.57 ± 25.16 mM). High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection was used to visualize the presence of oligosaccharides with degrees of polymerization of 3 to 7. Oligosaccharides from YB1 lysate treated sucrose mixtures also increased the anaerobic growth of Bifidobacterium breve 2141 at 37°C compared with untreated or KL B-gal treated sucrose mixtures. B-gal treatment of sucrose in nonfat milk with and without corn syrup can be a source of prebiotic oligosaccharides, although more work is needed to determine the composition of the oligosaccharides.

Summary: The whole cells and lysates of different strains of Lactobacillus delbrueckii ssp. bulgaricus were screened for the ability to synthesize galacto-oligosaccharides (GOS) through the transgalactosylation activities of their β-galactosidase (β-gal) at 50°C for 18 hours. The β-gal reactions from L. bulgaricus strains LB11 and YB1 were performed in increasing concentrations of lactose (146.1 to 876.4 mM) to determine which is optimal for the 2 different strains. The GOS were detected from whole cell and lysate reactions, although generally, the lysates yielded more GOS of varying degrees of polymerization.

Edible films based on the dairy protein casein have been developed, but widespread adoption will require pasteurization, and nothing is known about the effects of pasteurization on properties of the film solutions or their resulting films. This study investigated alterations in calcium and sodium caseinate-based film solutions due to commonly used pasteurization techniques: low temperature, long time; HTST; and UHT. All pasteurization conditions resulted in films with most textural properties and water vapor permeabilities having no significant changes in comparison to those made from nonpasteurized solutions; the only exceptions were films made from the UHT-processed calcium caseinate and HTST-processed sodium caseinate solutions having increased tensile strength and decreased yield stress, respectively. The solutions themselves, however, changed dramatically after higher temperature pasteurization conditions, with reduced viscosity (resistance to flow), and a weakened storage and loss moduli. The pasteurized solutions would thus be easier to process, except more complications may arise during casting. The particle size distribution of the solution based on calcium caseinate, but not the sodium caseinate, changed with all pasteurization techniques to become more polydisperse. Whereas lower temperature processing did not change solution stability, UHT increased stability of the sodium caseinate film solution, but decreased the suspension stability of the calcium caseinate film solution. Processing with UHT was the only pasteurization technique that proved effective in reducing microbial counts to below the limit of detection (1 log₁₀ cfu∙mL^-1). Overall, we demonstrated that caseinate-based film solutions may be pasteurized without concern of obvious changes to properties of resulting films; however, considerable rheological changes to the film-forming solutions are likely to occur.