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Summary: Feasibility of using konjac glucomannan hydrolysate (KGMH) as prebiotics and wall material for encapsulating probiotics was investigated. Prebiotic activity scores (PASs) were determined for KGMH, inulin, fructooligosaccharides and konjac glucomannan to assess their effectiveness in promoting growth of probiotics and inhibiting enteric mixture. Thermal tolerances of probiotics were also assessed. Lactobacillus rhamnosus L34 and L. acidophilus LA5 exhibited higher PASs and thermal tolerances and were selected for encapsulation; freeze drying and spray drying were used to form and dry encapsulated probiotics. Maltodextrin (MD), soy protein isolate (SPI) and KGMH, either individually or in combination, were comparatively used as wall materials. Freeze drying with SPI and KGMH resulted in highest survival rates for L. rhamnosus L34 (97.92%) and L. acidophilus LA5 (88.94%). In case of spray drying, MD, KGMH and combination of MD and KGMH resulted in drying yields of 55–71%; SPI‐containing formula resulted in lower yields (20–23%). Spray‐dried probiotics exhibited lower survival rates compared to their freeze‐dried counterpart. KGMH, particularly in combination with SPI, emerged as promising material for enhancing probiotics survival during encapsulation. [ABSTRACT FROM AUTHOR]

Konjac glucomannan (KGM) is a high-molecular-weight polysaccharide that was originally extracted from the corms (underground storage organs) of Amorphophallus konjac. KGM and its oligomers have been reported as dietary fibers that exhibit an array of health benefits. The depolymerization of KGM via enzymatic hydrolysis at different conditions gives products of low viscosity and can be used for coating materials in microencapsulation. In the present study, konjac glucomannan hydrolysates (KGMHs) were produced by enzymatic hydrolysis using commercial mannanase at pH 4.5 at 70 °C for 5–120 min, then KGMHs' molecular weight (Mw), Degree of Polymerization (DP) and their bioactivities were determined. A longer hydrolysis time resulted in KGMH of a lower DP. Oligoglucomannans (Mw < 10,000) could be obtained after hydrolysis for 20 min. The DP of KGMH rapidly decreased during an early stage of the hydrolysis (first 40 min); DP reached around 7 at the end of the hydrolysis. Antioxidant activities were determined by the DPPH radical scavenging and FRAP assays of KGMHs prepared at pH 4.5 and evaluated at pH 2.0–8.0 depending on pH. KGMH having lower Mw exhibited higher antioxidant activities. KGMHs having the smallest molecular weight (Mw = 419) exhibited the highest DPPH radical scavenging activity. Mw and pH have a greater impact on KGMHs' bioactivities which can be useful information for KGMHs as functional ingredients. [ABSTRACT FROM AUTHOR]

Glutamicibacter arilaitensis is one of the predominant bacterial species involved in the coloration of cheese rinds, especially smear-ripened cheeses. Besides well-known yellow-pigmented carotenoids, this species exhibits an ability to produce red pigments, as the occurrence of pink/red formation was previously found when co-cultured with a fungal strain. In this work, the red pigments synthesized by G. arilaitensis strains grown on cheese-based (curd) solid medium deacidified using Debaryomyces hansenii were identified. The analyses using HPLC equipped with both fluorescence and diode array detectors were performed to characterize the pigments extracted from a dry matter of the medium inoculated with either G. arilaitensis Re117, Po102, or Stp101. Based on the UV-vis absorption spectra, the elution order, and fluorescent property, compared to those of the porphyrin standards, eight metal-free porphyrins, including UPI, UPIII, 7PI, 6PI, 5PI, CPI, CPIII, and MPIX, were indicated as components of the red pigments produced by these G. arilaitensis strains. However, following the chromatographic profiles, the degree of porphyrins formed by each strain was apparently different. Regardless of precise quantitative measurement, the type strains Re117 and Po102 manifested a potential to produce a high amount of CPIII, whereas MPIX was formed by the strains Po102 and Stp101, but exceptionally high by the strain Stp101. The variation in both yield and form of the red pigments synthesized by the cheese-related bacterial G. arilaitensis has not previously been reported; therefore, our results provide the first information on these aspects. [ABSTRACT FROM AUTHOR]