Potential to increase the stability of milk riboflavin against photo-oxidative degradation
2011
Antone, U., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Food Technology | Sterna, V., Latvia Univ. of Agriculture, Auce, Dobele reg. (Latvia). Training and Research Farm Vecauce | Zagorska, J., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Food Technology. Dept. of Food Technology
Milk and other dairy foods are excellent natural sources of riboflavin (vitamin B2). Exposure of milk to light as one of the most serious dangers of riboflavin degradation, can take place at several stages from milking to the consumers, initiating the sensibilization of riboflavin, and resulting in the oxidation of milk, losses of nutritional value, and strong off-flavours that can make the oxidized milk unacceptable to consumers. The stability of milk components is dependent of a delicate balance between the anti- and pro-oxidative factors. Carotenoids are known as one of the strongest natural antioxidants. The aim of this study was to compare the influence of cow feed carotenoids on the milk riboflavin stability against photo-oxidative degradation. Milk was obtained from three experimental and one control cow groups. Experimental group’s feed was supplied with carotenoid sources: carrots, red palm oil and red palm oil concentrate. Milk samples were collected after 6 week long feed supplementation and exposed to direct sunlight for 1.5 and 3 hours. The losses of riboflavin measured by the fluorometric method was significantly lower (p is less than 0.05) in all experimental groups milk when cow diet was enriched with carotenoids from carrots, red palm oil, and red palm oil carotenoid concentrate, compared to the control group (respectively, 10.03, 10.82, 11.13, and 21.22% after 1.5 h storage, and 15.66%, 18.95%, 18.64%, and 23.48% after 3 h storage). A strong positive correlation between milk yellow colour intensity and its riboflavin stability was also observed.
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