# Applications of Pulsed Light Decontamination Technology in Food Processing: An Overview
## 6 Effect on Food Quality Characteristics
### Effects on Organoleptic Properties (Color, Texture and Flavor) of Food Products
While severe treatment conditions are detrimental to product sensory quality, optimized treatment conditions at particular light intensity, number of pulses and lamp distance  
Lipids in milk products might be quite susceptible to off-flavor generation auto-oxidation phenomenon, due to light. Slight aroma changes were observed in PL-treated goat milk [110] possibly due to photochemical changes in milk components and lipid oxidation. [PERSON] et al. [52] showed that adequately designed pulsed UV treatment process of milk does not induce lipid oxidation. Thus, properly designed fluid milk product PL treatment system are needed based on the optimized flow rate, fluence dosage, and residence time to minimize the effect on their color and sensory properties. [PERSON] [30] showed that no changes in color and taste occurred by PL in dry cottage cheese curd after severe treatment of 32 J/cm\({}^{2}\). Contrastingly, however, a smaller dose of 9.22 J/cm\({}^{2}\) adversely affected the sensory quality of cheese [130]. Color changes were significant for cheese treated by PL at 53.4 J/cm\({}^{2}\) for 40 s at 5 cm distance [102]. The color values a* and b* were significantly different from untreated ones, indicating changes in yellownness and redness. The effects of PL application on sensory qualities of meat, sea-food, fish and other processed foods have been extensively studied. [PERSON] et al. [131] showed the sensory attributes of the PL-treated fish remained acceptable and close to control samples. They concluded that fish was acceptable even after 15 days of refrigerated storage. However, pulses of 2.5-5 J/cm\({}^{2}\) of UV light did not change color in packaged catfish fillets [75]. In another study, salmon fillets, on PL treatment for 30 s at 3 cm distance and for 45 s at 5 cm distance showed excessive heating which resulted in color changes visually [81]. [PERSON] and [PERSON] [83] did not observe any changes in color and flavor after PL treatment of 5.4 J/cm\({}^{2}\) in chicken breast meat. [PERSON] et al. [85] observed significant quality alterations in PL-treated chicken frankfurters. The fluence level up to 67 J/cm\({}^{2}\) for 60 s treatment induced darker,greenish and yellowish tint in the treated frankfurters. This could be due to application of higher fluence. The sensory qualities of PL-treated bologna slices were observed to be adversely affected [132]. Researchers noticed change in redness value and sensory attributes for dose above 2.1 J/cm\({}^{2}\). [PERSON] and [PERSON] [133] studied the impact of pulsed UV light on quality attributes of ham. They observed darkening of ham after processing and storage up to seven days with increasing L* value, and a slight increase in yellowness due to the increase in b* and decreasing redness (due to decrease in a*) value, possibly because of the accumulation of metmyoglobin on surface. They also observed a decrease in the firmness of meat post-processing. Pork and salmon, after PL treatment showed significant color and odor changes [105] post-PL treatment. [PERSON] and [PERSON] [134] found that PL treatment degraded the organoleptic properties of cooked meat, whereas it did affect the sensory attributes of dry cured meats and fermented sausages. The higher fluence dosage (17 J/cm\({}^{2}\)) significantly changed the color parameter values of meat products. No significant differences in sensory and color quality were found for sea foods. Sulphur off-odor was detected in fresh egg pasta after PL treatment of 1.75 J/cm\({}^{2}\). However, no significant color change was observed [103]. As a matter of fact, fat content remains a decisive factor in PL treatment of meats with higher fat content leading to significant sensory changes. Fat however tends to increase the bacterial resistance to PL and thus fat rich meat products require treatment under severe conditions, jeopardizing their sensory characteristics.