Abstract #M70

# M70
Comparison of different types of acidity values of three phases of caprine cheese milk during Cheddar cheese manufacture.
R. Paswan*1, A. Siddique1, Y. W. Park1, 1Fort Valley State University, Fort Valley, GA.

There are several methods of measuring acidity of milk, including titratable acidity (TA), Soxhlet-Henkel (SH) value, acidity Dornic (AD) and acidity Therner (AT) values. TA is a measurement of any constituent that will react with or neutralize the 0.1 N sodium hydroxide. Fresh milk practically contains no lactic acid (LA), but still require an amount of NaOH to reach the phenolphthalein endpoint. During cheesemaking process, the cheese milk undergoes a variety of physicochemical changes. The objective of this study was to compare the differences in levels of LA, SH, AD and AT for 3 different stages of caprine cheese milk, such as fresh pasteurized milk (FPM), culture ripened milk (CRM) and whey milk (WM) during the entire procedure of Cheddar cheese manufacture. Three batches of fresh raw caprine milk were collected from the bulk tank of the Georgia Small Ruminant Research and Extension Center, Fort Valley State University, Fort Valley, GA, and pasteurized at 63°C for 30 min, cooled to 31°C, and then goat Cheddar cheeses were processed. The experimental cheese milk samples were taken at 3 different stages of cheese manufacture. The physicochemical parameters of acidity values were determined using a MilkoScan FT1, which is FTIR (Fourier Transform Infrared Spectroscopy) interferometer. The precision and stability of MilkoScan FT1 were calibrated by traditional AOAC approved fixed filter, which relies on every sine function being defined by its frequency (wavelength) and its amplitude (intensity) of IR beam. The results showed that LA, SH, AD and AT values for the FPM, CRM and WM stages were: 0.11, 0.17, 0.13; 5.34, 7.87, 5.85; 11.81, 17.83, 13.31; 12.86, 19.14, 14.71, respectively. All tested acidity values revealed that CRM samples were highest, followed by WM and FPM samples, indicating that the CRM samples cultured for one hour with Chymax starter contained significantly higher lactic acid levels generated by the starter culture bacteria. All tested acidity parameters showed the same trend of increased acidity in CRM compared with FPM and WM samples. It was concluded that the 4 tested acidity indicators of CRM had the highest values among the 3 phases of the caprine cheese milk.

Key Words: goat milk, cheese milk, acidity values