# Research on Physicochemical Properties and Taste of Coppa Influenced by Inoculation with Staphylococcus During Air-Drying Process

## TL;DR

This study shows how inoculating air-dried pork coppa with Staphylococcus bacteria improves its taste and quality by altering its chemical properties.

## Contribution

The study identifies specific Staphylococcus strains and key metabolites that enhance the taste and physicochemical properties of air-dried pork coppa.

## Key findings

- Staphylococcus inoculation significantly reduced water activity and pH in coppa.
- Key taste metabolites like citrulline and isovaleric acid were identified as differentiators.
- Inoculation improved color, hardness, chewiness, and overall taste acceptability.

## Abstract

Air-dried pork coppa is highly favored for its unique organoleptic and flavor characteristics. However, the traditional long processing cycle and uncontrollable environmental conditions lead to unstable product quality. Staphylococcus mediates the reduction in nitrite to nitric oxide via nitrite reductase; the resulting nitric oxide then binds to myoglobin, forming nitrosylmyoglobin that endows meat products with a characteristic bright red. It could also improve the activity of lipase and protease, promoting the flavor. In this study, Staphylococcus carnosus and Staphylococcus xylosus as starter cultures have been applied to air-dried coppa. After Staphylococcus inoculation, the water activity and pH value of coppa significantly decreased compared with those of naturally fermented coppa (p < 0.05). Meanwhile, it improved the color and increased the hardness and chewiness, which in turn enhanced the overall taste of organoleptic acceptability. The 1H NMR spectra showed that the main taste metabolites were free amino acids and organic acids. Citrulline, formic acid, isobutyric acid, and isovaleric acid might be the key metabolites distinguishing between those with or without Staphylococcus inoculation. This study suggested that inoculation with Staphylococcus xylosus and Staphylococcus carnosus played an important role in improving the physicochemical properties and taste development of coppa.