HIGHLY ACTIVE FREEZE-DRIED PROBIOTIC CONCENTRATES WITH LONG SHELF LIFE

Abstract

The application of probiotics in the composition of products intended to have long shelf life is limited due to their mandatory refrigeration storage. Increase in the resistance of probiotics to the production  conditions  and  improvement  of  their  viability  throughout  storage  is  achieved  by microencapsulation. The preservation of probiotic strains for a long period of  storage and low cost transportation and thus, resulting in ready-to-use cultures for dairy and other food-related industries including  in  the  field  of  probiotics  is  facilitated  by  freeze-drying  using  appropriate  cryoprotectant media. The used cryoprotectants are hydrocolloids which are natural, vegetable raw materials, with numerous beneficial physiological effects on the body. The aim of the present study is obtaining highly active probiotic freeze-dried bioproducts of selected probiotic strains by applying a combined modern biotechnology with the following main stages: selection, immobilization of the selected strains in the hydrocolloid  matrix,  cryoprotection,  freezing  and  freeze drying.  The  selected  probiotic  strains Lactobacillus plantarum X2 and Lactobacillus paracasei RN5 are immobilized and freeze-dried using combined  hydrocolloid  matrix  -  sodium  alginate  and  high-ester  pectin.  The  survival  of  the  two
lyophilized  microorganisms  after  lyophilization  and  in  the  course  of  storage  for  nine  months  is monitored  –  both  strains  retain  high  concentrations  of  active  cells.  The  used  hydrocolloids  are appropriate for  the  mechanical immobilization  of  cellular  cultures and  as  cryoprotectants.  The  new combined biotechnology allows the preparation of probiotic bioproducts with long shelf life and intact probiotic  potential  for  application  as  supplements  for  foods  with dietary  purpose  and  in  the prophylaxis and treatment of gastrointestinal disorders.