Evaluation of microencapsulation of a Bifidobacterium strain with starch as an approach to prolonging viability during storage

Abstract

Aims: To optimize a spray coating process for the production of encapsulated microspheres containing viable Bi®dobacterium cells and to determine whether the readily gelatinized modi®ed starch coating used in this study improved bacterial survival in foods or under acid conditions. Methods and Results: An air inlet temperature of 100°C was demonstrated to be optimal for the spray drying process, as it afforded good drying, low outlet temperatures (45°C) and resulted in less than 1 log reduction in bi®dobacteria numbers during drying. Maximum recovery yields of 30% were obtained after optimizing the air aspiration conditions. The average size of the Bi®dobacterium PL1-containing starch microparticles was determined by scanning electron microscopy to be of the order of 5 lm. The starch-coated cells did not display any enhanced viability compared with free PL1 cells when exposed to acid conditions for 6 h or in two dry food preparations over 20 d storage at ambient temperature (19±24°C). Determination of 1491 nucleotides of the 16S rRNA gene from PL1 indicated that it shared 97% homology with a previously sequenced Bi®dobacterium ruminantium strain. Conclusions: Our data demonstrated that, although spray drying is a valuable process for encapsulating bi®dobacteria, further work is required to ascertain a more appropriate coating material that will protect this strain against adverse environmental conditions. Signi®cance and Impact of the Study: The production of small, uniformly coated microspheres containing viable bi®dobacteria using an affordable and industrially convenient process, such as spray drying, has commercial implications for the production of probiotic products. Although popular for use as a coating polymer by the food industry, this study indicated that modi®ed starches might not be suitable for use as an encapsulating material for probiotic strains.

Technology and potential applications of probiotic encapsulation in fermented milk products

“…The shape and size of capsules affecting the sensory quality of final products are important issues for industrial production. Furthermore, in spray-drying process, the outlet temperature may affect the colour of the capsules due to a Maillard reaction (a form of non-enzymatic browning similar to caramelization) (McMaster et al, 2005;O′Riordan et al, 2001;Su et al, 2007). The addition of encapsulated probiotic bacteria did not significantly change the appearance and color, acidity, flavor, or aftertaste of the yoghurts, but significantly affected their textural properties (smoothness) (Krasaekoopt et al, 2006).…”

Encapsulation Technology to Protect Probiotic Bacteria

“…Inlet temperatures of above 60 °C resulted in poor drying and the sticky product often accumulated in the cyclone. Higher inlet temperatures (>120 °C) resulted in higher outlet temperatures (>60 °C) and significantly reduced the viability of encapsulated [55]. The logarithmic number of probiotics decreases linearly with outlet air temperature of the spray-drier (in the range of 50 ºC -80 ºC) [56].…”

“…The successful spray drying of Lactobacillus and Bifidobacterium have previously reported for a number of different strains, including L. paracasei [57,58], Lactobacillus curvatus [59], L. acidophilus [60], L. rhamnosus [61] and Bifdobacterium ruminantium [8]. Specifically, FavaroTrindade and Grosso [6] used spray drying to encapsulate B. lactis and L. acidophilus in the enteric polymer cellulose acetate phthalate enriched with the fructooligosaccharide Raftilose1 (a prebiotic).…”

“…Encapsulation is a process to entrap active agents within a carrier material and it is a useful tool to improve living cells into foods, to protect [3,4,5,6,7], to extend their storage life and to convert them into a powder form for convenient use [8,9,10,11]. In addition, encapsulation can promote controlled release and optimize delivery to the site of action, thereby potentiating the efficacy of the respective probiotic strain.…”

Supercritical CO2 interpolymer complex encapsulation improves heat stability of probiotic bifidobacteria

“…Better survival of bifidobacteria stored in glass than polyester bottles was reported previously (Dave and Shah 1997;Hsiao et al 2004). Glass has also been shown to improve survival of bacteria when compared to poly (ethylene terepthalate) (PET) bottles (O'Riordan et al 2001). PET has higher oxygen permeability than glass (Ishibasi and Shimamura 1993; Hsiao et al 2004).…”