Reduced fouling and enhanced microbial inactivation during online sterilization of cheese whey using UV coil reactors in series

Abstract

The effectiveness of coil UV reactor series for the online sterilization of cheese whey was compared to those of the single conventional and coil reactors at various flow rates (5-70 mL/min). The residence time varied from 168 to 12 min and from 48 to 24 min for the single and the series reactors, respectively. Hundred percent destruction efficiency could not be achieved in the single reactors whereas in the coil reactor series the destruction efficiency reached 100% at the flow rates of 35 and 40 mL/min. The rate of microbial destruction was described by polynomial equation for the single coil reactor and by exponential equations for the single conventional reactor and the coil reactor series. The temperature of the effluent decreased with the increase in flow rate in all the reactors. The maximum effluent temperatures in the single conventional reactor, single coil reactor and coil reactor series were 45.8, 46.1, and 36.4 degrees C (Deltat = 20.8, 21.1, 11.4 degrees C), respectively. The flow in all the reactors was laminar (R ( e ) = 1.39-20.10) and the Dean number was in the range of 1.09-15.41 in the coil reactors. Visual observation revealed less fouling on the UV lamps of coil reactors than on that of the conventional reactor due to the impact of Dean flow. The total operating time during which 100% destruction efficiency is achieved prior to the advent of fouling was 240 min in the coil reactor series compared to only 45 min in the conventional reactor.

Use of immobilised biocatalysts in the processing of cheese whey

“…In the United States, of the 13.4 billion kg produced in the same year, 42% was disposed of as a waste product. Although whey production has increased over the past 28 years by 165% in both countries, the utilisation and disposal practices have remained essentially the same [6]. However, because of its high biochemical oxygen demand (40,000-60,000 mg/L), whey disrupts the biological process of conventional sewage treatment plants and its disposal into these plants has, therefore, been banned by many municipalities [7].…”

Fermented whey beverages: A review of process fundamentals, recent developments and nutritional potential

“…This hinders UV transmittance by absorbing, scattering, reflecting and attenuating the incident light and reduces microbial deactivation efficiency (Mahmoud and Ghaly 2004). Nonetheless, using reactors with UV coils in series with long treatment times and improving UV penetrability by using low flow rates and thin flow thicknesses have shown success in achieving ~100% elimination of microbes in cheese whey (Mahmoud and Ghaly 2004; Singh and Ghaly 2006). However, these conditions along with the high biomolecule and mineral content in whey promote rapid fowling of the quartz‐liquid interface of UV lamps.…”

Ultraviolet Light Applications in Dairy Processing

“…However, fouling was seen as a major problem when the temperature of cheese whey increased. As a solution to the fouling problem, coil reactor series were recommended instead of conventional reactor by Singh and Ghaly [36]. Table 2 summarizes the microbial inactivation and technical characteristics of UV light system used for milk that were reported in the studies cited above.…”