Pressure affects enzyme inactivation and color of orange juice.Nowadays, the trend in consumer tastes for fruit juices is towards freshly squeezed products that have a fresh taste and a preserved natural flavor. Orange juice is a critical product on this front, in part because of the nutritional and sensory damage that occurs when it undergoes traditional thermal pasteurization pasteurization (păs'ch  rĭzā`shən, -rīzā`shən), partial sterilization of liquids such as milk, orange juice, wine, and beer, as well as cheese, to destroy . High-pressure
homogenization homogenization (həmŏj'ənəzā`shən), process in which a mixture is made uniform throughout. Generally this procedure involves reducing the size of the particles of one component of the mixture and dispersing them evenly could be a good alternative to traditional thermal
processing, especially for pumpable foods.
Scientists in Brazil evaluated the influence of processing pressures and pH on the destruction rates of pectinmethylesterase and color in orange juice. Orange juice from the Pera orange variety was obtained using a commercial extractor. The juice was then passed through a 48-mesh 0.297-mm screen. Researchers pumped the juice through a homogenizer A laboratory equipment for the homogenization of various types of material, such as tissue, plant, food, soil, and many others. Many different models have been developed using various physical technologies for the disruption. valve at different pressures using two synchronized overlapped intensifiers at a flow rate of approximately 270 mL per minute. The inlet temperature was kept at 10 C and soluble solids at 10.0 Brix. After processing, the product was immediately cooled to 4 C using a stainless steel coil in an ice bath. Scientists used a complete experimental design to evaluate the effect of pH (ranging from 3.7 to 4.5) and pressure (ranging from 100 MPa to 300 MPa) on the product. The quality parameters analyzed were pectinmethylesterase inactivation inactivation /in·ac·ti·va·tion/ (in-ak?ti-va´shun) the destruction of biological activity, as of a virus, by the action of heat or other agent. and total color difference (L, a, b color system). Two second-order polynomial polynomial, mathematical expression which is a finite sum, each term being a constant times a product of one or more variables raised to powers. With only one variable the general form of a polynomial is a0xn+a equations were successfully obtained for pectinmethylesterase inactivation and total color difference (R2=0.95 and 0.94, respectively). The researchers found that pressure had a bigger effect than pH on the pectinmethylesterase inactivation and on the color difference. The inactivation increased with increases in pressure and decreases in pH, while the color difference increased with decreases in pressure and pH. The inactivation rate of pectinmethylesterase reached its maximum at the higher pressure and lower pH, while the total color difference reached its maximum at the lower pressure and pH. Further information. M. Cristianini, Food Technology Department, Faculty of Food Engineering, UNICAMP UNICAMP Universidade de Campinas (Campinas, São Paulo State, Brazil) , Campinas, Sao Paulo, 13081-970, Brazil; phone: +55 19 3788-4026; fax: +55 19 3788-4027; URL URL in full Uniform Resource Locator Address of a resource on the Internet. The resource can be any type of file stored on a server, such as a Web page, a text file, a graphics file, or an application program. : www.fea.unicamp.br. |
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