Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurisation and their correlation to sensory analysis (original) (raw)

Featured Application: The current study was conducted to identify and measure the off-flavoring volatile compounds and microbial load of pasteurized fluid milk, stored at different temperatures, as a possible indicator of its keeping quality. Abstract: (1) Background: Multiple attempts have been conducted to correlate milk keeping quality with chemical, physical or bacteriological parameters. These methods only measure the chemical changes in milk produced by bacteria. Headspace solid-phase micro-extraction (HS-SPME) is an economic and recent method used to measure both volatile compounds and microbial load in milk, also allowing to keep the quality of the milk product. (2) Methods: The present study was conducted to identify and measure the off-flavoring volatile compounds through gas chromatography coupled with flame ionization detector (GC-FID) and the microbial load of pasteurized fluid milk stored at different temperatures, as a possible indicator of its keeping quality. (3) Results: The highest results were obtained to acetone, followed by butanone, pentanal and ethanol. These mean values were significantly enhanced from the 0 to 19th day of storage, at 10 • C. At day 19th, the minimum score for aroma, flavor and overall acceptability were also recorded as 4.33 ± 0.17, 4.02 ± 0.06, 4.00 ± 0.04, respectively. Likewise, maximum values for standard plate count (Log 10 CFU 15.54 ± Appl. Sci. 2019, 9, 959; doi:10.3390/app9050959 www.mdpi.com/journal/applsci Appl. Sci. 2019, 9, 959 2 of 16 0.40 mL −1) and total psychotroph count (Log 10 CFU 11.67 ± 0.30mL −1) were reported at 10 • C and 4 • C. (4) Conclusion: HS-SPME/GC-FID methodology revealed to be very sensitive and capable to be applied in volatile compounds quantification in pasteurized milk produced during the storage period at different temperatures.