Changes in Fatty Acid and Volatile Compound Profiles during Storage of Smoked Cheese Made from the Milk of Native Polish Cow Breeds Raised in the Low Beskids.

Abstract

Simple SummaryCheese, due to its high nutritional value, is an important element of the daily diet of many consumers. About one third of cow milk produced globally is processed into a wide assortment of cheeses. Most of them are produced on a mass scale in industrial conditions. One factor determining cheese quality is the quality of the milk it is made from. The milk of pasture-grazed cows is known to have higher content of compounds benefiting human health. Consumers are increasingly interested in artisanal products, including cheese, manufactured directly on farms or in small, local processing facilities, regarding them as natural, less processed, and free of additives. Milk for the production of this type of cheese usually comes from cows of native breeds kept on family farms. Smoking is one of the oldest traditional methods used to prolong the shelf-life of food. It imparts a pleasant aroma to cheese and improves its palatability. The literature lacks studies on the quality of smoked cheese during storage. The aim of this study is to assess changes in chemical composition and in fatty acid and volatile compound profiles during storage of smoked cheese made from the milk of native Polish cow breeds.This study investigated changes in the proximate chemical composition and profiles of fatty acids and volatile compounds of 12 smoked cheeses made from the milk of native Polish cow breeds used in Beskid Niski. Analyses were performed during the shelf life i.e., in the 1st, 21st, 42nd and 69th day of storage. Studies have shown that thanks to smoking and vacuum-packing, the chemical composition of cheese remained stable throughout the whole shelf-life. Up until the 21st day of storage, there were no statistically significant changes in the profile of fatty acids as well as volatile compounds. Changes were observed only after the mentioned storage time. After 21 days, there was a significant (p < 0.05) and steady decrease (up to day 69) in the proportion of odd-chain (by about 36%), branched-chain (by about 17%) and unsaturated fatty acids (by slightly over 1%). Among unsaturated fatty acids (p < 0.05), however, there was a significant increase in the proportion of monounsaturated fatty acids (by 5%) and a decrease in polyunsaturated fatty acids of nearly 12%. Storage lowered (by 47% in the 69th day of storage) the content of the conjugated linoleic acids (CLA), as well as lowered the n6 to n3 fatty acids ratio. During the 69 days of storage, the content of carboxylic acids increased to more than 50%. In the period from the 42nd to 69th day of cheese storage, the content of butyric acid and hexanoic acids increased twofold, whereas that of octanoic acid increased more than tenfold. Fifty-four volatile compounds were identified in the cheese. The largest group was ketones (34%), whose level decreased during storage, with 2-butanone, 3-hydroxy- (acetoin) and 2-butanone predominating. The research found that due to their low odor threshold, carboxylic acids may have negatively affected the flavor profile of the cheese.