Improving Viability of Bifidobacteria by Microentrapment and Their Effect on Some Pathogenic Bacteria in Stirred Yoghurt

Abstract

Fifteen batches of stirred yoghurt were made to study the effect of microentrapment on the viability of bifidobacteria and their ability to inhibit the growth of E. coli and Staph. aureus. Entrapped cells of Bifidobacterium bifidum and Bifidobacterium infantis were able to produce antimicrobial agents which inhibited E. coli and Staph. aureus used as test organisms. Viable counts of unentrapped bifidobacteria decreased sharply, while entrapped cells of bifidobacteria were quite stable during refrigerated storage of stirred yoghurt. Bif. infantis was more tolerant to storage conditions than Bif. bifidum. Microentrapment of bifidobacteria improved their survival during storage of stirred yoghurt, especially Bif. bifidum, whose viability was not significantly (P>0.05) different from entrapped Bif. infantis. Viable counts of E. coli decreased during storage of stirred yoghurt. Addition of bifidobacteria caused a sharp decrease in the viability of E. coli. E. coli growth was not dectected at the 5th day, when entrapped cells of bifidobacteria were added to stirred yoghurt, while E. coli growth was not detected at the 7th day of storage in yoghurt containing unentrapped bifidobacteria. Addition of Bif. bifidum inhibited the growth of E. coli more effectively than Bif. infantis. Staph. aureus showed similar patterns to E. coli, except that Staph. aureus was more tolerant to storage conditions. The counts of total bacteria, lactobacilli and Streptococcus salivarius subsp. thermophilus increased up to the third day then declined till the end of storage. Titratable acidity increased gradually during the first 3 days of storage then increased slightly up to the end of storage, while pH values dropped during storage. Adding of bifidobacteria, E. coli and Staph. aureus did not affect significantly (P>0.05) the counts of lactobacilli and Str. salivarius subsp. thermophilus, acidity and pH value.

Effect of microencapsulation plus resistant starch on survival of Lactobacillus casei and Bifidobacterium bifidum in mayonnaise sauce

“…Furthermore, microencapsulation with resistant starch may improve viable cells of bacteria in acidic foods. This finding is in agreement with those of Kebary and Hussein (1999), Sultana et al (2000), Krasaekoopt et al (2003), Homayouni et al (2008) and Mirzaei et al (2012). The himaize starch could give a higher survival ability of probiotics (10 5 to 10 6 /g) in acidic environment of mayonnaise sauce.…”

“…A limiting factor in survival of probiotic bacteria has been reported as low pH (3.6 to 4.6) of mayonnaise sauce owing to the concentration of acetic acid (Radford and Board, 1993;Khalil and Mansour, 1998). It has been proven that microencapsulated probiotics survive better in acid conditions (Khalil and Mansour, 1998;Kebary and Hussein, 1999;Mokarram et al, 2009;Nazzaro et al, 2009;Chávarri et al, 2010;Brinques and Ayub, 2011;Su et al, 2011). Alginate microcapsules can be prepared by emulsion and extrusion techniques.…”

Encapsulation in an alginate–goats’ milk–inulin matrix improves survival of probiotic Bifidobacterium in simulated gastrointestinal conditions and goats’ milk yoghurt

“…). Similarly, other encapsulating materials such as alginate (Kebary and Hussein ), alginate–starch (Adhikari et al . ) and κ‐carrageenan have been observed to improve survival of probiotic Bifidobacterium species in fermented dairy foods under refrigerated storage.…”

“…Furthermore, it was observed that capsules containing prebiotics could provide the carbon and nitrogen sources for encapsulated probiotics leading to higher survival rates for Bifidobacterium and Lactobacillus in milk (Chen et al 2005). Similarly, other encapsulating materials such as alginate (Kebary and Hussein 1999), alginate-starch (Adhikari et al 2000) and j-carrageenan have been observed to improve survival of probiotic Bifidobacterium species in fermented dairy foods Table 2 Survival of free and encapsulated Bifidobacterium animalis subsp. lactis BB-12 after incubation in simulated gastric juice (pH 2) at 37°C for 30, 60, 90 and 120 min and in simulated intestinal juice pH (7.5) at 37°C for 2 h (value represents both after gastric and intestinal digestion in vitro).…”

Encapsulation for delivering bioactives in aquaculture

“…Such drug delivery vehicles can also be used to prevent the release of unwanted materials into the environment and extend the shelf life of the encapsulated materials (Zuidam & Shimoni ; Huq et al . ) and ensures a target‐specific delivery of bioactives in a host (Kebary & Hussein ; Picot & Lacroix ). Delivery of bioactives in aquaculture farms is a new challenge to formulation scientists.…”