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J Food Sci Technol (NovDec 2010) 47(6):613619 DOI 10.1007/s13197-010-0108-z
ORIGINAL ARTICLE
Study of Mucor spp. in semi-hard cheese ripening
Na Zhang & Xin-Huai Zhao
Revised: 18 December 2009 /Accepted: 26 September 2010 /Published online: 18 November 2010 # Association of Food Scientists & Technologists (India) 2010
Abstract A strain of Mucor spp. isolated from a fermented soybean food in central China was smeared on the surface of semi-hard cheese to investigate its role in cheese ripening. Cheese ripening indices showed increase by 34 fold upon ripening of cheese for 90 days. Electrophoretic studies revealed that caseins in the cheese were degraded gradually during ripening forming several low molecular weight peptides, especially of 14.4 kDa. Texture profile analysis and microstructure study of the cheese showed that the proteolytic activity of Mucor led to desirable texture development in ripened cheese. The study indicates that the strain of Mucor used in the experiment has desirable proteolytic capability for use in cheese system.
Keywords Mucor . Cheese . Ripening . Proteolysis .
Texture . Microstructure
Introduction
Mould has an important role in cheese processing, especially for surface mould-ripened cheeses such as Brie (Fernndez-Salguero 2004), Camermbert (Gaborit et al. 2001), Neufchatel (Fernndez-Salguero 2004), Gamalost (Sienkiewicz-Szapka et al. 2009), and interior mould-ripened cheeses such as Stilton (Ercolini et al. 2003), Roquefort (DallAsta et al. 2008), Gorgonzola (Carminati et al. 2004) and Tulum cheeses (Cakmakci et al. 2008). Mould metabolism and degradation of milk constituents i.e.
protein, fat by exogenous and endogenous enzymes lead to an improvement in texture, flavor and nutritional quality of cheeses. Specific texture and desirable flavor of surface mould-ripened cheese are correlated with proteolytic and lipolysis changes respectively. Moulds used in cheese include Penicillium roqueforti, Geotrichum candidum/P. candidum, P. caseicolum and P. camemberti and its mutant (Gripon 1993). Fernndez-Salguero (2004) reported that gradual hydrolysis of proteins led to the formation of low molecular weight compounds in Blue cheese. Complete hydrolysis of both s1- and -caseins was reported in Blue cheese (Gripon 1993). OSullivan et al. (2005) studied the soluble nitrogen and amino acid content of cheese made and ripened with P. camemberti using animal and vegetable rennets.
Mao-tofu, a fermented soybean food covered with white fungus (Mucor) mycelia, is produced in central China. The processing of Mao-tofu is...