Taxonomic structure of the yeasts and lactic acid bacteria microbiota of pineapple (Ananas comosus L. Merr.) and use of autochthonous starters for minimally processing Raffaella Di Cagno a , Gainluigi Cardinali b , Giovanna Minervini a , Livio Antonielli b , Carlo Giuseppe Rizzello b , Patrizia Ricciuti c , Marco Gobbetti a, * a Department of Plant Protection and Applied Microbiology, University of Bari, via Amendola 165/a, 70126 Bari, Italy b Department of Applied Biology, University of Perugia, Italy c Department of Biologia e Chimica Agro-Forestale ed Ambientale, University of Bari, Italy article info Article history: Received 26 July 2009 Received in revised form 16 November 2009 Accepted 17 November 2009 Available online 26 November 2009 Keywords: Yeasts Lactic acid bacteria Fermented pineapple Autochthonous starter abstract Pichia guilliermondii was the only identified yeast in pineapple fruits. Lactobacillus plantarum and Lactobacillus rossiae were the main identified species of lactic acid bacteria. Typing of lactic acid bacteria differentiated isolates depending on the layers. L. plantarum 1OR12 and L. rossiae 2MR10 were selected within the lactic acid bacteria isolates based on the kinetics of growth and acidification. Five techno- logical options, including minimal processing, were considered for pineapple: heating at 72  C for 15 s (HP); spontaneous fermentation without (FP) or followed by heating (FHP), and fermentation by selected autochthonous L. plantarum 1OR12 and L. rossiae 2MR10 without (SP) or preceded by heating (HSP). After 30 days of storage at 4  C, HSP and SP had a number of lactic acid bacteria 1000 to 1,000,000 times higher than the other processed pineapples. The number of yeasts was the lowest in HSP and SP. The Community Level Catabolic Profiles of processed pineapples indirectly confirmed the capacity of autochthonous starters to dominate during fermentation. HSP and SP also showed the highest antioxi- dant activity and firmness, the better preservation of the natural colours and were preferred for odour and overall acceptability. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Pineapple (Ananas comosus L Merr.) is the most representative fruit of the Bromeliaceae family. It is mainly cultivated in the trop- ical and subtropical regions. In 2007, the production of pineapple was estimated to be ca. 188,733,577 tonnes (www.fao.org). As tropical fruit, its cultivation is only preceded by banana and citrus (Bartholomew et al., 2002). Ripe fruits are consumed fresh, also as topping in desserts and salads, cooked in pies, cakes and puddings or processed. Canned pineapple and pineapple juice are generally subjected sterilization and consumed throughout the world, mainly because of their pleasant, and unique aroma and flavour (Morton, 1987; Bartolome et al., 1995). The FAO organization estimated that ca. 184,833 tonnes of pineapple per year are consumed in Italy (www.fao.org). Besides sensory properties, the nutritional features of pineapple also deserve an interest. Pineapple core is a source of fibres (Stuab et al., 1983) to be used as functional ingredients for bakery and meat products (Prakongpan et al., 2006). Pineapple fruits and their extracts (bromelain) are proposed as potential anti- inflammatory agents in rheumatoid arthritis, ulcerative colitis, colon inflammation, chronic pain and asthma (Secor et al., 2005; Onken et al., 2008). Overall, fresh fruits are essential components of the human diet and there is considerable evidence of the health and nutritional benefits associated with their consumption. Public health institu- tions recommend the consumption of at least five daily servings of fruits. Especially, fresh and minimally processed pineapple (e.g., peeled, cut and packaged fruit salads), but also pineapple juice are strongly recommended for the nutritional properties. Minimally processed pineapples are present in the market under different shapes: cubes, slices, chunks and cored whole fruit. Since the bulky inedible crown and peel tissue are removed, they have the commercial advantage of decreasing the weight for transport (Budu and Joyce, 2005). Nevertheless, two major problems might affect the quality of minimally processed pineapples. The shelf-life is very limited (ca. 2e3 days) because of the pulp browning and * Corresponding author. Tel.: þ39 080 5442949; fax: þ39 080 5442911. E-mail address: gobbetti@agr.uniba.it (M. Gobbetti). Contents lists available at ScienceDirect Food Microbiology journal homepage: www.elsevier.com/locate/fm 0740-0020/$ e see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.fm.2009.11.012 Food Microbiology 27 (2010) 381e389