14A-25 |
Sensory quality and some physical-chemical changes in UHT whole milk during storage at 25 or 35 oC |
E. XAVIER1, J. B. P. CHAVES2, T. J. P. D. Silva3, R. Rodrigues4, A. A. D. Silva4, and M. R. D. Souza4. (1) Ministério da Agricultura - Brazil, Ministério da Agricultura - Brazil, Av. Francisco Sales, no. 780, zip code 30 150 - 221, Belo Horizonte, 30150 - 221, Brazil, (2) Departamento de Tecnologia de Alimentos, Universidade Federal de Viçosa, DTA/UFV, UFV, Viçosa, 36 571 - 000, Brazil, (3) Departamento de Tecnologia e Inspeção de Produtos Animais, Unversidade Federal Fluminense, dta/ufv, DTA/UFV, vicosa, 36 571 - 000, Brazil, (4) Departamento de Tecnologia e Inspeção de Produtos Animais, Universidade Federal de Minas Gerais, Escola de Veterinária da UFMG, Belo Horizonte, 30 120 - 000, Brazil Five random sample groups (replications) of whole UHT treated milk were obtained from one commercial mark processed in the Belo Horizonte area, in the State of Minas Gerais-Brazil. Each sample group (replication), collected a week apart, had 42 cartoon packages of 1000 mL. Half of the packages (21) was stored at 25 ± 2oC and the other half at 35 ± 2oC, for a time period of 154 days. The sensory attributes: cooked, caramelized and oxidized flavors and typical UHT milk flavor were analyzed at times: 0, 7, 14, 28, 42, 56, 70, 84, 98, 126 and 154 days, by a trained eight members taste panel. Titrable acidity, pH and hydroximethylfurfural (HMF) values were determined at the same time intervals indicated. Sensory analysis results up to 154 days showed significant changes along storage time. Cooked flavor average scores decreased more sharply during the first 50 to 60 days and continued declining slowly up to 100 days storage and, they were not significantly (P„d0.05) affected by storage temperature. Typical flavor average scores decreased linearly with storage time, with a greater decreasing rate (P„T0.05) at 35 oC storage. Caramelized and oxidized flavors also increased linearly with storage time, with a much greater increase in milk stored at 35 oC. Physical-chemical analysis presented significant (P„T0.05) variations either with time or storage temperature. The pH decreased and the titrable acidity increased linearly with storage time. Again, the much greater effect was at 35 oC storage. HMF value variation with storage time followed a quadratic model, decreasing at the beginning up to 70 to 90 days and increasing sharply after 120 days, with a much greater increase at 35 oC storage. There was no significant (P„d0.05) correlation between HMF values and average flavor scores.
Session 14A, Dairy Foods: General developments in dairy technology I
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