Helados

Food Chemistry 111 (2008) 50–55

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Food Chemistry
journal homepage: www.elsevier.com/locate/foodchem

Effect of microencapsulation and resistant starch on the probiotic survival and sensory properties of synbiotic ice cream
A. Homayouni a,*, A. Azizi b, M.R. Ehsani c, M.S. Yarmand c, S.H. Razavi c
a

Department of Food Science and Technology,Faculty of Health and Nutrition, Tabriz University of Medical Sciences, Tabriz, Iran Iranian Agricultural Engineering Research Institute, Ministry of Agriculture, Tehran, Iran c Department of Food Science and Technology and Technology, Faculty of Biosystem Engineering, Campus of Agriculture and Natural Resources, The University of Tehran, Tehran, Iran
b

a r t i c l e

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a b s t r a ct
Two types of synbiotic ice cream containing 1% of resistant starch with free and encapsulated Lactobacillus casei (Lc-01) and Bifidobacterium lactis (Bb-12) were manufactured. The survival of L. casei and B. lactis were monitored during the product’s storage for 180 days at À20 °C. The viable cell number of L. casei and B. lactis in the free state in prepared ice cream mixture was 5.1 Â 109 and4.1 Â 109 CFU/mL at day one and after 180 days storage at À20 °C, these numbers were decreased to 4.2 Â 106 and 1.1 Â 107 CFU/ mL, respectively. When we encapsulated the mentioned probiotic bacteria in calcium alginate beads, the probiotic survival raised at rate of 30% during the same period of storage at same temperature. In general, the results indicated that encapsulation can significantlyincrease the survival rate of probiotic bacteria in ice cream over an extended shelf-life. The addition of encapsulated probiotics had no significant effect on the sensory properties of non-fermented ice cream in which we used the resistant starch as prebiotic compound. Ó 2008 Elsevier Ltd. All rights reserved.

Article history: Received 22 September 2007 Received in revised form 7 March 2008Accepted 10 March 2008

Keywords: Probiotic Prebiotic Synbiotic Survival Microencapsulation Ice cream

1. Introduction Probiotics are defined as live microorganisms which, when administered in adequate amounts confer a health benefit to the consumers. Prebiotics are non-digestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favourable growth oractivity of a limited number of indigenous bacteria (FAO/WHO, 2001). A food product containing both probiotics and prebiotics is named as synbiotic or functional food (Homayouni, Ehsani, Azizi, Razavi, & Yarmand, 2007a). There is a synergy between probiotics and prebiotics in synbiotic products. Prebiotic compounds are consumed by probiotics as a carbon or energy source in the colon. This results inan increase in the probiotic count and the reduction of pathogen microorganisms in the gut (Vernazza, Rabiu, & Gibson, 2006). Probiotic bacteria have been incorporated into fermented and non-fermented ice cream which is an ideal vehicle for delivery of these organisms in the human diet (Akin, Akin, & Kirmaci, 2007; Hekmat & McMahon, 1992; Kailasapathy & Sultana, 2003; Ravula & Shah, 1998). Due toits neutral pH, synbiotic ice cream is also gaining popularity (Akin et al., 2007). The pH of non-fermented ice cream is closer to 7 and this provides possibility for satisfactory survival of probiotic bacteria (Christiansen, Edelsten, Kristiansen, &
* Corresponding author. Tel.: +98 411 3357581; fax: +98 411 3340634. E-mail addresses: Homayouni@ut.ac.ir, Homayounia@tbzmed.ac.ir (A. Homayouni).0308-8146/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2008.03.036

Nielsen, 1996). The efficiency of added probiotic bacteria depends on the dose level, temperature, type of dairy foods and presence of air (Homayouni, Ehsani, Azizi, Yarmand, & Razavi, 2006a), their viability must be maintained throughout the product’s shelf-life and the gut environment...