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G. P. SCHAMBERGER and T. P. Labuza. Dept. of Food Science & Nutrition, Univ. of Minnesota, 1334 Eckles Ave., 225 Food Science & Nutrition Bldg., Saint Paul, MN 55108-6099 Extended shelf life (ESL) milk has a niche market in various parts of the world, but has limited acceptability by US consumers. The negative sensory profile of this product can be attributed to increased thermal processing, resulting in the Maillard reaction that consequently causes the formation of off flavors and colors. The ability to inhibit the Maillard reaction in milk would allow for a consumer-accepted product with increased shelf life and greater food safety. The objective of this project was to evaluate the ability to minimize the Maillard reaction in milk during processing and storage. Initial testing determined the ability of cysteine hydrochloride and green tea extracts - catechin, epicatechin, and epigallocatechin gallate to decrease the Maillard reaction. Raw skim milk mixed with these compounds was thermally processed using a Microthermics pilot plant thermal processing unit at 138ºC for 6 seconds. The product was filled into sterile 15 ml caped tubes and stored at 4, 12, 23, 35 and 45ºC. Samples were assessed for brown pigment formation at 420 nm, the formation of hydroxymethylfurfural (HMF), and the production of fluorescent compounds using front face spectroscopy. The results showed a decrease in brown pigment formation, HMF, and fluorescence levels of the milk containing cysteine or the green tea extracts when compared to the control milk after initial thermal processing and during storage. The addition of cysteine resulted in the greatest decrease in the formation of fluorescent compounds after processing. These results indicate the Maillard reaction can be inhibited in ESL milk.
Session 31, Dairy Foods: General I
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |