Sensory and electronic nose analysis of Noble goat’s milk from Cilento (Italy)

The interest in extensive farming which is sustainable for the environment and animal welfare has recently increased. In such context, an approach that arises from these assumptions, aimed at enhancing the quality of dairy products, is the “Noble method”, applied in Cilento area (PSR Campania 2014/2020-Measure 16.1) for zootechnical productions. The disciplinary of the “Noble method” prohibits the use of silage in the livestock feeding system, provides quantitative limits for the use of energy concentrates and dictates specific rules for the botanical composition of pasture forage (at least 5 different cultivars in the ration). Due to constraints related to the feasibility of extensive grazing, the “Noble method” appears to be a promising strategy especially for small ruminants, such as sheep and goat farms. In this investigation, sensory analysis was applied to test the differences between noble goat’s milk and non-noble standard goat’s milk. Then, E-nose, consisting of ten metal oxide semiconductor sensors was used to classify the two types of goat’s milk, in terms of rearing and feeding system, and to test the discrimination feasibility of the device. The milk samples were taken in five different times over a period of six months (lactation period effect) from 18 individual goats. In terms of sensory differences, Noble milk scored higher for descriptors such as grassy and sweet aromatic, typical of an extensive pasture farmed milk, while regular milk scored higher for descriptors such as silage and malty. E-nose resulted capable of classifying the two milk types in terms of animal feed (87.78% correct classification of milk samples according to the feeding system). Since the “Nobile method” follows a production specification, it is necessary to control and guarantee the authentic quality of the dairy products, and the E-nose has proved to be a quick, reproducible and simple method for routine control analyses.