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Keywords:

  • bacterial release;
  • bacterial survival;
  • Lactobacillus reuteri ;
  • microencapsulation;
  • probiotic;
  • spray drying;
  • whey

Abstract

Aims

Formulations of dietary probiotics have to be robust against process conditions and have to maintain a sufficient survival rate during gastric transit. To increase efficiency of the encapsulation process and the viability of applied bacteria, this study aimed at developing spray drying and encapsulation of Lactobacillus reuteri with whey directly from slurry fermentation.

Methods and Results

Lactobacillus reuteri was cultivated in watery 20% (w/v) whey solution with or without 0·5% (w/v) yeast extract supplementation in a submerged slurry fermentation. Growth enhancement with supplement was observed. Whey slurry containing c. 109 CFU g−1 bacteria was directly spray-dried. Cell counts in achieved products decreased by 2 log cycles after drying and 1 log cycle during 4 weeks of storage. Encapsulated bacteria were distinctively released in intestinal milieu. Survival rate of encapsulated bacteria was 32% higher compared with nonencapsulated ones exposed to artificial digestive juice.

Conclusions

Probiotic L. reuteri proliferate in slurry fermentation with yeast-supplemented whey and enable a direct spray drying in whey. The resulting microcapsules remain stable during storage and reveal adequate survival in simulated gastric juices and a distinct release in intestinal juices.

Significance and Impact of the Study

Exploiting whey as a bacterial substrate and encapsulation matrix within a coupled fermentation and spray-drying process offers an efficient option for industrial production of vital probiotics.