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Morphology, FTIR fingerprint and survivability of encapsulated lactic bacteria ( Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus ) in simulated gastric juice and intestinal juice
Author(s) -
Vodnar Dan C.,
Socaciu Carmen,
Rotar Ancuţa M.,
Stãnilã Andreea
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2010.02406.x
Subject(s) - streptococcus thermophilus , lactobacillus , bacteria , lactobacillus delbrueckii subsp. bulgaricus , microbiology and biotechnology , lactic acid , food science , chemistry , biology , genetics
Summary Microencapsulation of bacteria in hydrocolloid beads is known as a potential way to enhance and protect their survivability in the digestive tract. We encapsulated a mix of two lactic bacteria ( Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) in sodium alginate (AG) and chitosan (CH) matrices. The morphological parameters of beads containing bacteria were comparatively measured. The FTIR fingerprint can discriminate the presence of bacteria into the beads, identifying specific absorption peaks for bacteria located at 1750, 2852 and 2926 cm −1 . To check the survivability of bacteria, beads were incubated in simulated gastric juice (pH 1.5) and intestinal juice (pH 7.2) for different periods of time, up to 120 min. The 2% AG beads, better than CH beads, provided best protection of bacterial survivability. Encapsulated mix of S. thermophilus and L. delbrueckii subsp. bulgaricus can behave as a probiotic bacteria, viable, surviving in the simulated gastric and intestinal juice.