An Investigation of Volatile Flavor Compounds and Lipolysis-Oxidation in Coppa as Affected by the Inoculation of Coagulase-Negative Staphylococcus during the Air-Drying Stage

Abstract

This study aimed to explore the effects of coagulase-negative Staphylococcus inoculation on flavor generation and lipolysis-oxidation in Coppa. Acid lipase, neutral lipase, phospholipase, and lipoxygenase (LOX) activities, as well as free fatty acids, volatile compounds, and sensory evaluation, were determined during the fermentation and air-drying processes of Coppa over 40 days. Staphylococcus carnosus and Staphylococcus xylosus or a combination of both strains were selected for this study, and natural fermentation was treated as a control. The results showed that Staphylococcus inoculation significantly enhanced lipase and LOX activities, and mixed strains had a superior effect. Palmitic acid, stearic acid, linoleic acid, and oleic acid were identified as the predominant free fatty acids in Coppa, with the mixed fermentation group exhibiting the highest contents. Acids, aldehydes, alcohols, ketones, esters, and phenols were found for the volatile compounds in Coppa. These findings thus suggested a positive role of Staphylococcus inoculation in activating lipolysis-oxidation and contributing to the flavor formation of Coppa during the air-drying stage.

Keywords: Staphylococcus fermentation; lipolysis; pork collar butts; volatiles.

Figure 1

Aroma sensory evaluation of Coppa samples among the four groups (Natural fermentation group, NA; Staphylococcus carnosus group, RS; Staphylococcus xylosus group, MS; Mixed Staphylococcus strains group, HS).

Figure 2

Changes in neutral lipase, acid lipase, phospholipase, and LOX activities in Coppa with or without inoculation of Staphylococcus strains during the air-drying process. Means ± standard errors are shown. Different lowercase letters (a–e) represent significant variations in the different air-drying days within the same group (p < 0.05), and different uppercase letters (A–D) indicate significant inter-group differences at the same air-drying stage (p < 0.05).

Figure 3

Heat map of hierarchical cluster analysis between the four differential groups. Total saturated fatty acid (ΣSFA); total monounsaturated fatty acids (ΣMUFA); total polyunsaturated fatty acids (ΣPUFA); total free fatty acids (TOTAL FA).