Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt Protective effects of the use of taro and rice starch as wall material on the viability of encapsulated Lactobacillus paracasei subsp. Paracasei O. Alfaro-Galarza a , E.O. López-Villegas b , N. Rivero-Perez a , D. Tapia- Maruri c , A.R. Jiménez-Aparicio c , H.M. Palma-Rodríguez a,* , A. Vargas-Torres a a Universidad Autónoma del Estado de Hidalgo, Instituto de Ciencias Agropecuarias (ICAP), Av. Universidad km 1, Rancho Universitario, C.P. 43600, Tulancingo de Bravo, Hidalgo, Mexico b Instituto Politécnico Nacional, Central de Microscopia, ENCB, Mexico City, Mexico c Instituto Politécnico Nacional, CEPROBI, Km 6 Carr, Yautepec-Jojutla, Calle Ceprobi No. 8, Apartado Postal 24, Yautepec, 62731, Mexico ARTICLE INFO Keywords: Starch Encapsulation Lactobacillus Viability In-vitro digestion ABSTRACT In this study, was evaluated the protective effect of two microencapsulation materials of different sized starch granules, taro (5.16 μm) and rice (6.99 μm), on the survival of Lactobacillus paracasei subsp. paracasei (LPSP) at controlled spray-drying inlet air temperatures of 70, 115, and 135 °C. Physicochemical properties, encapsulation efficiency, and gastrointestinal viability of microcapsules were analyzed. Rice microcapsules showed a slight increase in water activity and moisture values when compared with taro microcapsules. Viability of the mi- crocapsules was affected drastically with the increase in inlet temperature during spray-drying. Small-sized taro starch granules showed a better formation of spherical aggregates for one logarithmic cycle in the initial viability of LPSP. Electron microscopy showed less LPSP on the outside of the taro starch microcapsules. The findings in this study indicated that use of microcapsules constructed from taro starch can offer better protection to pro- biotic strains. 1. Introduction The intake of probiotics microorganisms has risen owing to the in- creased awareness regarding their associations with multiple health benefits, especially in the digestive system, when administered in ap- propriate doses. FAO/WHO (2002) reported that the consumption of probiotic microorganisms should range from 10 6 to 10 7 CFU/g or mL (CFU, colony-forming unit). However, when bacteria are used as pro- biotics, their viability must remain stable throughout the duration of the shelf-life of the food product and their resistance to the acidic en- vironment of the stomach and to bile salts in the small intestine must be maintained. Other factors that affect bacterial viability are pH, lactic and acetic acid, hydrogen peroxide, and dissolved oxygen content of the product (Picot & Lacroix, 2004). Therefore, various technologies have been developed to protect microorganisms against adverse environ- mental factors and to improve the delivery of bioactive molecules and living cells within foods, for example, spray-dried microencapsulation (Avila-Reyes, Garcia-Suarez, Jiménez, San Martín-Gonzalez, & Bello- Perez, 2014; Peredo, Beristain, Pascual, Azuara, & Jimenez, 2016). Studies have reported the use of carrageenan, alginate, cellulose acetate phthalate, gelatin, chitosan, starch, or combination of some these hydrocolloids (Avila-Reyes et al., 2014; Cortés et al., 2014) as wall material in microencapsulation by spray-drying to preserve probiotic microorganisms. Some studies have reported that starches with small granule size, or modified starches, can also be used as wall material because they have shown to be effective encapsulation agents (Avila-Reyes et al., 2014; Palma-Rodríguez, Alvarez-Ramírez, & Vargas-Torres, 2018). Other studies have reported that small granule starch has a greater protective effect on encapsulated chemical compounds (Hoyos-Leyva, Chavez- Salazar, Castellanos-Galeano, Bello-Perez, & Alvarez-Ramirez, 2018; Zhao & Whistler, 1994). This improvement in the protective effect could be explained by the greater tendency of small granule starch to form spherical aggregates (Gonzalez-Soto, de la Vega, Garcia-Suarez, Agama-Acevedo, & Bello-Perez, 2011). However, there is little in- formation on the use of small granule starch in the encapsulation of probiotics. Pankasemsuk, Apichartsrangkoon, Worametrachanon, and Techarang (2016) reported protective effect of microcapsules made with Hi-maize starch-alginate mixtures and showed that the increase in alginate concentration improved the longevity of Lactobacillus casei 01. Avila-Reyes et al. (2014) evaluated the use of native rice starch and inulin as wall material in the microencapsulation of Lactobacillus https://doi.org/10.1016/j.lwt.2019.108686 Received 13 December 2018; Received in revised form 20 September 2019; Accepted 24 September 2019 * Corresponding author. E-mail addresses: heidi_palma9528@uaeh.edu.mx, apolovt@hotmail.com, palma.heidi@gmail.com (H.M. Palma-Rodríguez). LWT - Food Science and Technology 117 (2020) 108686 Available online 25 September 2019 0023-6438/ © 2019 Published by Elsevier Ltd. T