The dry blend ingredients in roasted coffee, ground coffee or coffee extracts are dependent on the product’s formulations. If using crude coffee beans, roasting is the unit operation in which coffee beans are put in contact with hot surfaces or gases to raise their temperature to 220°C (Robertson, 2009). The roasted and ground coffees are brewed with hot water at a temperature from a moderately-below boiling point to moderately-above boiling point (European Patent EP 1206206 B1, 2004). Ready to drink coffees are generally pasteurized and chilled or sterilized and stored at ambient temperatures (Robertson, 2009).
Pasteurization and sterilization are key unit operations that causes microbial inactivation in ready-to-drink coffee drinks (Kilcast & Subramaniam, 2011). The coffee base is mixed with the water in a mixing tank using a high-shear mixer to reconstitute the coffee or tea extract. The dairy or soy base and key flavors are then mixed into the mixing tank using a high-shear mixer.
After the ready-to-drink beverage is homogenized, the beverage is commercially sterilized via ultra-high temperature (UHT) or high temperature short time (HTST) pasteurization techniques. Aseptic or retort packaging equipment may be used to produce a shelf stable ready-to-drink beverage (United State Patent No. US 2008/0317924 A1, 2008).
If there is no machine for the UHT process, the pasteurization process can be preceded prior to filling into containers to kill spoilage microorganisms in order to produce safer end products with a longer shelf life (WIPO Patent No. WO 2014204454 A1, 2014).
There are different types of pasteurization processes. A HTST treatment (High Temperature/Short Time) is a pasteurization method using a temperature of at least 71.7 °C for 15 to 20 seconds. Flash pasteurization on the other hand uses temperatures of 71.5 °C to 74 °C for about 15 to 30 seconds. Retorting typically is treatment for 5 to 35 minutes at 121 to 125° C. Any of these pasteurization or sterilization techniques or any other suitable techniques may be used after gassing the RTD beverage (WIPO Patent No. WO 2014204454 A1, 2014). The FDA requirement for pasteurization is at least 160°F (71°C) for 6 seconds (Zemser, 2015).
Ingredients such as stabilizers, emulsifiers and acidity regulators can also be added to improve shelf stability and quality of end products (United State Patent No. US 2008/0317924 A1, 2008).
Polypropylene can be retorted with a maximum process temperature of around 127°C but some grades exhibit poor-low temperature tolerance, thus impacting their characteristics (Yam, 2010).
In aseptic sterilization, a minimum container temperature is developed and held for a predetermined period of time (e.g., 55° F. for 5 seconds) after application of the sterilant. Hot sterile air is delivered at a high volume and relatively low temperature to dry the container and to prevent the container from being heated to its softening temperature (US Patent No. US20050097863 A1, 2005).
Connor, C. W. & Gutwein, R. W. (2004). Method of utilizing delayed dilution, mixing and filtering to provide customized varieties of fresh-brewed coffee on demand. European Patent EP 1206206 B1.
Kilcast, D. & Subramaniam, P. (2011). Food and beverage stability and shelf life. Cambridge: Woodhead Publishing Limited.
Robertson, G. L. (2009). Food packaging and shelf life: A practical guide. Boca Raton: CRC Press.
Robertson, G. L. (2009). Food packaging and shelf life: A pratical guide. Boca Raton: CRC Press.
Sher, A., Cilliers, C., Alahverdzhieva, V., Fu, J. T., Sahai, D. (2014). Ready to drink beverages with foam formed by microwave energy. WIPO Patent No. WO 2014204454 A1.
Taggart, T. (2005). Apparatus for aseptic packaging. US Patent No. US20050097863 A1.
Yam, K. L. (2010). The Wiley Encyclopedia of Packaging Technology. USA: John Wiley & Sons.
Yang, A. (2008). Beverage and method of making same. United State Patent No. US 2008/0317924 A1.
Zemser, R. (2015). The Changing Face of Beverage Processing. The World of Food Ingredients, 10-15.