Changes in physico-chemical properties of milk under ultraviolet radiation

Abstract

The use of ultraviolet radiation in the treatment of milk and other liquid foods is a very promising field of study since it reduces their bacterial load. It is rarely used to increase the vitamin D content and modify the protein and fatty acid composition of milk. The paper describes how different parameters of ultraviolet radiation influence such characteristics of raw and pasteurized milk as the mass fraction of total protein, nonprotein nitrogen content, active and titratable acidity, general bacterial load (QMA&OAMO), fatty acid composition, and vitamin D content. Low-pressure gas-discharge lamps were used to treat a 400 µm moving layer of milk with ultraviolet radiation. The radiation time, its doses, and the milk flow rate changed in the ranges of 5–25 min, 5.1–102 mJ/cm2, and 0.04453- 0.13359 m3/s, respectively. We identified optimal radiation ranges that lead to both a lower microorganism content and a higher vitamin D content. Our study also determined specific correlations in the mutual changes of the given parameters. The treatment ranges did not produce any significant changes in other physico-chemical properties of milk. We also found that vitamin D was synthesized in raw and pasteurized milk in a similar way. Moreover, there was an insignificant decrease in the vitamin D content in milk treated with ultraviolet radiation during storage for up to 48 hours. On the whole, the results indicate that the treatment of milk with ultraviolet radiation in the dosage range from 5.1 to 102 mJ/cm2 has a complex effect on the total bacterial load (QMA&OAMO) and vitamin D content,
 whereas it has almost no effect on the protein and fatty acid composition.

UV Light Application as a Mean for Disinfection Applied in the Dairy Industry

“…The study of Matak et al [66] showed that ultraviolet irradiation at the wavelength 254 nm and a dose of 15.8 ± 1.6 mJ/cm 2 resulted in changes in the chemical and sensory properties of fluid goat milk. Whereas, Kharitonov et al [65] showed no effect on fatty acid profile during UV treatment of milk either raw or pasteurized for 5-25 min which corresponded to the surface bactericidal irradiation dose 5.1-102 mJ/cm 2 .…”

“…No difference [62] Little effect when treated with less than 4.2 J/cm 2 fluences [63] Protein precipitation No effect Observed [59] Fatty acid profiles HTST treatment: almost no effect, UHT treatment: Considerable changes [64] especially decrease in PUFA content and increase in saturated FA, including low molecular FA Almost no change [65,66] Lipid oxidation Little [62] or significant changes [67]; temperature-dependent No changes [52] Level of vitamin D3 No impact [68] Increases [65] Level of vitamin B12 Reduces [62] No impact [62] Thiobarbituric acid reactive substances No significant difference [62] Significant [66] or no [62] change…”

Optimized Chemical Analysis of Cow’s Milk Proteins: Evaluation of New Measuring Devices

“…They are sent to the laboratory under a cold regime using a stacked ice pack cooler. Before analysis on the Milko Scan FT2 and Kjeldahl K-375/376, the milk samples were heated to 40 °C for 20 min and stirred several times to ensure homogeneous distribution of these components [14].…”

Research of the polyethylene packaging layer structure change in contact with a food product at exposure to ultraviolet radiation

“…В технологиях молочной продукции все большее распространение находит использование ультрафиолетового (УФ) облучения. [5]. Эффективность обеззараживания упаковки данным безреагентным способом подтверждена проведенными исследованиями [6,7,8].…”