RESUMO
In this work, we investigated the effects of the ultrasonic power (0, 200, 400 and 600â¯W) on non-thermal processing of an inulin-enriched whey beverage. We studied the effects of high-intensity ultrasound (HIUS) on microbial inactivation (aerobic mesophilic heterotrophic bacteria (AMHB), total and thermotolerant coliforms and yeasts and molds), zeta potential, microstructure (optical microscopy, particle size distribution), rheology, kinetic stability and color. The non-thermal processing applying 600â¯W of ultrasonic power was comparable to high-temperature short-time (HTST) treatment (75⯰C for 15â¯s) concerning the inactivation of AMHB and yeasts and molds (2 vs 2 log and 0.2 vs 0.4 log, respectively), although HIUS has reached a lower output temperature (53⯱â¯3⯰C). The HIUS was better than HTST to improve beverage kinetic stability, avoiding phase separation, which was mainly attributed to the decrease of particles size, denaturation of whey proteins and gelation of polysaccharides (inulin and gellan gum). Thus, non-thermal processing by HIUS seems to be an interesting technology for prebiotic dairy beverages production.
Assuntos
Bebidas , Viabilidade Microbiana , Prebióticos , Ondas Ultrassônicas , Soro do Leite , Alimento Funcional , Temperatura Alta , Tamanho da Partícula , Desnaturação Proteica , SonicaçãoRESUMO
O Mycobacterium bovis causa a tuberculose zoonótica, doença que afeta os animais e o homem podendo causar a morte, sendo o leite uma importante via de transmissão da doença para o homem. A pasteurização do leite é a principal medida para quebrar essa cadeia de transmissão, cujos parâmetros de tempo e temperatura foram definidos através de experimentos que datam desde o fim do século XIX, com base na resistência térmica do M. bovis e da Coxiella burnetti, então considerados os mais resistentes patógenos não formadores de esporos que contaminam o leite. No Brasil são aprovados os binômios 62ºC a 65ºC por 30 minutos e 72ºC a 75ºC por 15 a 20 segundos. Entretanto, com o passar dos anos e surgimento de novas tecnologias (PCR, Spoligotyping e outras técnicas biomoleculares) foi possível observar diferenças genéticas intra-espécie. Assim, este projeto tem por objetivo avaliar e comparar o comportamento de dois espoligotipos de M. bovis (SB0120 e SB1033) frente aos dois protocolos de pasteurização utilizados no país. Para tanto, leite integral UHT foi contaminado com esses espoligotipos e submetido aos dois processos térmicos, em Banho-Maria. O leite foi semeado em meio sólido Stonebrink-Leslie e a contagem de colônias foi feita após 45 dias de incubação a 37ºC. Não houve neste experimento diferença entre as resistências térmicas dos dois espoligotipos, no entanto detectou-se uma maior importância da fase de aquecimento na redução do agente do que da fase de manutenção da temperatura, para os dois espoligotipos, nos dois processos.
Mycobacterium bovis causes zoonotic tuberculosis disease that affects animals and humans and can cause death, the milk is an important route of disease transmission to humans. The pasteurization of milk is the main measure to break the transmission chain, whose time and temperature parameters were defined by experiments dating from the late nineteenth century, based on thermal resistance of M. bovis and Coxiella burnetti, considered then the most resistant non-spore-forming pathogens that contaminate the milk. In Brazil, there are two approved binomials 62ºC to 65ºC for 30 minutes and 72ºC to 75ºC for 15 to 20 seconds. However, over the years and the emergence of new technologies (PCR, spoligotyping and other biomolecular techniques) was observed genetic differences intra-species. Thus, this project aims to evaluate and compare the behavior of two spoligotypes of M. bovis (SB0120 and SB1033) compared to the two pasteurization protocols used in the country. To this end, UHT milk was contaminated with these spoligotypes and subjected to two thermal processes in a water bath. The milk was streaked on solid medium Stonebrink-Leslie and colony counting was done after 45 days of incubation at 37ºC. This experiment showed that there was no difference between the thermal resistances of the two spoligotypes, however it was detected a greater importance of the heating phase in reducing the agent that the maintenance phase of temperature for the two spoligotypes, in both cases.