14A-44 |
Quantitative analysis of water-soluble free fatty acids and amino acids in Swiss cheese with different culture ratio and warm room treatment |
T. JI, V. B. Alvarez, W. J. Harper, and H. Ruiz-Espinosa. Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., 110 Parker Food Science Bldg., Columbus, OH 43210-1007 A standard make procedure for small-scale Swiss cheese is being established to allow many experiments to be made with respect to conveniences and economics. The amount of starter cultures and the duration of warm room treatment (WRT) are important factors for developing cheese flavor. Quantification of free amino acids (FAAs) and volatile water-soluble free fatty acids (FFAs) are performed as a measure of flavor development in Swiss cheeses made using different starter culture usage rates and WRT. The objective of this research is to assess the effect of different WRT time and usage level of starter cultures on the concentration of water-soluble FFAs and FAAs as a flavor contributor in Swiss cheese. Analysis of FAAs in cheese as a measure of proteolysis extent was performed by Cd-ninhydrin method (microplate assay). This method is based on the colorimetric reaction of the amino group in amino acids with ninhydrin in presence of cadmium salts. A capillary gas chromatograph equipped with a flame ionization detector was used for the quantitative analysis for water-soluble volatile FFAs in Swiss cheese. Starter culture usage rates did not affect significantly (P > 0.05) the development of FAAs through out the ripening time of the cheeses. However, ripening time in warm room had a significant effect on the concentration of FAAs in the Swiss cheese. The FAAs augmented considerably during the WRT. A continuous, almost linear increase in FAA was shown during 108 days and 115 days of ripening time in the small-scale Swiss cheese. Starter culture usage rates did not affect significantly the concentration of FFAs (acetic acid and propionic acid) in 3-wk warm room treated Swiss cheeses, but the concentration of the acids in 2-wk warm room treated cheeses were affected significantly by starter culture levels. A 3-wk warm room treatment and a 1:3 ratio of propionibacteria to Streptococcus thermophilus and Lactobacillus helveticus were necessary to obtain similar concentrations of FFAs and FAAs in Swiss cheese reported in previous studies.
Session 14A, Dairy Foods: General developments in dairy technology I
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