Enhancing probiotic encapsulation with konjac glucomannan hydrolysate

Abstract

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.