Vol. 65, No. 4, 2000—JOURNAL OF FOOD SCIENCE 731 © 2000 Institute of Food Technologists Sensory and Nutritive Qualities of Food JFS: Sensory and Nutritive Qualities of Food Improvement of the Sensory Properties of Dry Fermented Sausages by the Superficial Inoculation and/or the Addition of Intracellular Extracts of Mucor racemosus J.M. B RUNA, M. FERNÁNDEZ, E.M. HIERRO, J.A. ORDÓÑEZ, AND L. DE LA HOZ ABSTRACT: The effect of inoculation of the “salchichón” (dry fermented sausage ) surface with an atoxigenic, pro- teolytic, and lipolytic strain of Mucor racemosus and/or the addition of a intracellular extract of the same mold on the ripening process was studied. Four batches of salchichón were manufactured: control, superficially inoculated, added with intracellular extract, and a combination of both treatments. Superficial mold modified the amino and free fatty acid contents, volatile compounds, and sensory properties. Intracellular extract degraded free amino acids, producing a rise in ammonia and volatile compounds. Both treatments combined improved significantly the sensory properties, which were given scores higher than control sausages at the end of ripening. Key Words: dry fermented sausages, molds, Mucor racemosus, ripening, sensory properties Introduction M EAT PRODUCTS RIPENED WITH MOLDS ARE PART OF A LONG- standing gastronomic tradition in some European coun- tries such as Spain, Italy, France, Germany, Switzerland, and Ro- mania. The surface coating of molds is considered to be an indi- cator of a successful ripening process and a good-quality final product. This is usually composed of a natural microflora com- prised of different species and families, the characteristics and development of which depend on the nature of the product, du- ration of the ripening process, and ripening conditions (Anders- en 1992). The nature of this flora has been studied in both cured hams (Huerta and others 1987; Hinrichsen and Pedersen 1995) and fermented sausages (Grazia and others 1986; Roncalés and others 1991; Trigueros and others 1995; Toledo and others 1997). The beneficial effects of the fungal flora in fermented prod- ucts are due to their antioxidant role (Bigelis 1992) and their ca- pacity to regulate the surface microclimate, producing a more uniform dehydration (Grazia and others 1986; Lücke 1986). They also give the product an agreeable appearance (highly appreci- ated in Southern Europe) and, in some cases, present extracellu- lar proteolytic and lipolytic activity (Trigueros and others 1995; Toledo and others 1997; Larsen 1998; Larsen and Jensen 1999). It has been demonstrated recently that molds can produce a wide range of volatile compounds as a result of their secondary me- tabolism (Pastore and others 1994; Sunesson and others 1995; Larsen 1998), which can play an important role in the develop- ment of the products’ aroma. Finally, from the perspective of consumer safety, the use of molds as starter cultures could pre- vent the growth of altering and potentially micotoxigenic species (Leistner and others 1993). Lipid and protein hydrolysis has a very limited direct reper- cussion on the development of the aromatic and sapid com- pounds of these products. Several authors have tried to acceler- ate the ripening process or potentiate the flavor and aroma of raw, dry fermented sausages by adding proteases and lipases of different origins (Díaz and others 1993, 1996, 1997; Fernández and others 1995a, 1995b; Zalacain and others 1995, 1996, 1997a, 1997b; Naes and others 1995; Blom and others 1996; Melendo and others 1996; Zapelena and others 1997, 1999). In summary, this research demonstrates that the addition of these enzymes to fermented sausages produces a rise in the concentration of pre- cursors (amino acids and free fatty acids) of aromatic and sapid compounds but does not accelerate the transformation of these into volatile compounds. Therefore, in accordance with previous findings, the com- bined extracellular proteolytic and lipolytic activity of molds and their intracellular metabolic activity on amino acids and fatty ac- ids could produce a greater accumulation of volatile compounds than in conventional fermented sausages. The objective of this work was to demonstrate the effect of inoculation of the surface with a Mucor racemosus strain isolated from fermented sausages and addition to the mixture of an intracellular extract of the same mold of proven ability to breakdown amino acids (Bruna and others 1998b, 1999) in an attempt to accelerate the production of volatile compounds and improve the sensory properties of raw fermented sausages. Results and Discussion L ACTIC BACTERIA WERE THE DOMINANT MICROBIOTA IN ALL THE batches studied. Initial values of around 10 6 cfu/g reached a maximum count after 5 d of approximately 10 8 cfu/g, which was maintained until the end of the ripening process (data not shown.) Similar results have been described by Díaz and others (1993, 1996), Fernández and others (1995a), and Bruna and oth- ers (1999, 2000). The microbiota that developed in MSA began at initial values of around 10 5 cfu/g, which decreased to 10 3 to 10 4 cfu/g at the end of the ripening process. The level of these micro- organisms rose during the 1 st 2 wk to later decrease towards the end of the process, although higher values were reached in batches S and E+S. The mold and yeast counts in the interior of the fermented sausages remained stable at around 10 4 cfu/g over the whole ripening period. The evolution of pH was similar to that observed by a number of authors in different fermented sausages (Fernández and oth-