UV processing and storage of liquid and solid foods: Quality, microbial, enzymatic, nutritional, organoleptic, composition and properties effects

Abstract

Non-thermal food processing technologies have been explored extensively in recent years in order to develop food products with extended shelf life as well as preserved nutritional and organoleptic characteristics in accordance with the changing consumer demands (Falguera et al., 2011a; Sanchez-Moreno et al., 2009). Ultraviolet (UV) irradiation is one of the non-thermal processes that can be applied to reduce the microbial load in liquid foods and surfaces, and to sterilize food packages and packaging materials, and environments involved in food processes (Jimenez-Sanchez et al., 2017a; Bintsis et al., 2000). UV light is subdivided into three regions as short-wave UV (UV-C, 200 and 280 nm), medium-wave UV (UV-B, 280 to 315 nm), and long wave UV (UV-A, 315 to 400 nm). The different types of effects on microorganisms can be caused by UV light of different wavelengths. The effectiveness of UV light on microorganisms results primarily from the fact that DNA molecules absorb UV photons between 200 and 300 nm, with peak absorption around 260–265 nm. This causes DNA damage by altering the nucleotide base pairing, thereby creating new linkages between adjacent nucleotides, particularly between pyrimidine bases, on the same DNA strand and ultimately results in cell death (Zimmer and Slawson, 2002). Peak et al. (1984) proposed that the dimer formation is not the only requirement to damage the DNA. Absorption of different wavelength photons by different molecular groups in the long DNA molecule can damage or destroy these bond groups. Thus, different bonds in the DNA can be affected with photons of different energy (Neister, 2014).