Abstract: Flavour is both an important part of the sensory evaluation of raw milk and a comprehensive expression of the intrinsic quality of dairy products.Corresponding to the senses of smell,taste and touch in human,the flavour profile of raw milk can be analyzed in three dimensions:Odour,taste and mouthfeel,respectively.Volatile compounds are not only the main source of flavour, but also a very important flavour contributor, only some of the volatile compounds contribute to the flavour formation.The main volatile compounds in raw milk include terpenoids,acids (such as C4-C12 fatty acids),ketones (such as methyl ketones),aldehydes (such as nonenal and heptenal),esters (such as γ-lactone),phenols (such as p-cresol) and sulfides (such as dimethyl sulfide).Volatile compounds are the determining factor in the flavour of raw milk,but raw milk is highly sensitive and easily disturbed by chemical substances,which makes the flavour of raw milk is difficult to control objectively,therefore flavour is highly susceptible to the quality of dairy products.Therefore,on the basis of ensuring the fresh flavour,it is necessary to strictly control the interference of various external factors on the flavour.Raw milk flavour is closely related to a variety of factors,such as diet,drinking water and barn environment.At present,diet is considered to be the most important and sensitive factor affecting the flavour of milk and dairy products,and the nutrients such as carbohydrates,fats and proteins in diet can affect the flavour substances in milk through different ways,thereby changing the flavour of raw milk.In summary,the diet largely determines the composition of volatile compounds that affect the flavour of raw milk.In this paper,the flavour characteristics of raw milk were elaborated from three dimensions of odour,taste and mouthfeel,and the main volatile compounds in raw milk and the effects of diet,drinking water and barn environment on the flavour of raw milk were reviewed,in order to provide a theoretical basis for the flavour and quality control of raw milk.

Key words: raw milk; flavour; volatile compounds