Composition, Organoleptic Characteristics, Fatty Acid Profile and Oxidative Status of Cow's Milk and White Cheese after Dietary Partial Replacement of Soybean Meal with Flaxseed and Lupin

In most Mediterranean countries, soymeal is an imported and economically unstable feedstuff that unpredictably affects the profitability of dairy farms. Here we examined whether the partial substitution of soymeal with a mixture of locally produced flaxseed and lupins could affect milk yield and cheese production in dairy cows. Sixty Holstein cows were fed either a standard food, or a meal in which 50% of soymeal was replaced by a flaxseed-lupin (FL) mixture. Milk yield and composition, as well as cheese characteristics of five replicates, were examined. The feed modification did not affect the general health and milk yield of the animals. Milk yield and composition, as well as cheese characteristics, were examined. The feed modification did not affect the general health and milk yield of the animals. Milk from the FL group had decreased levels of saturated fatty acids, while cheese made from milk from this group had increased polyunsaturated fatty acids when compared to controls. These results imply that replacement of soymeal with flaxseed and lupin is profitable as it confers special characteristics to milk and cheese that are of benefit to human health. The effect of partial substitution of soybean meal by equal quantities of flaxseed and lupins in diets of Holstein dairy cows and heifers was investigated. A total of 6 animals (30 multiparous and 30 primiparous) were allocated into two equal groups in a randomised block design and fed control (group CO) or modified (group FL) TMR diets from three weeks prior to calving until day 40 postpartum. The TMR of group CO contained corn, barley, soybean meal, rapeseed cake, corn silage, and Lucerne hay, whereas in group FL equal quantities of whole flaxseed and lupins were used to replace 50% of the soybean meal in the TMR. All animals were fed twice daily with a daily allowance of 24 kg dry matter intake per animal. Milking was carried out three times daily and milk yield was recorded during every milking. Milk samples were analysed for chemical composition and SCC content. White cheeses were manufactured from bulk milk of each group at industrial level. Bulk milk and white cheese were analysed for chemical composition and fatty acid profile; cheese was also assessed for its organoleptic properties. Results indicate that milk yield did not differ among groups. Lipid oxidation values were similar among the groups, for both milk and cheese. However, FL inclusion resulted in lower (p < 0.05) protein carbonyls and higher (p < 0.05) phenolic compounds in both milk and cheese samples. Milk from the FL group had decreased palmitic (p < 0.05) and myristic (p < 0.05) and increased oleic (p < 0.05) and linolenic acid (p < 0.05) when compared to group CO. White cheese from group FL showed a decrease in saturated fatty acids (SFA) (p < 0.05), an increase in monounsaturated fatty acids (MUFA) (p < 0.05), and a higher increase in polyunsaturated fatty acids (PUFA) (p < 0.05) when compared with that of group CO. The white cheese of cows fed diets with flaxseed and lupins showed compositional and organoleptic properties quite similar to control group cheese; aroma, texture, and color were acceptable and desirable in both cheeses. However, increased levels of n-3 polyunsaturated fatty acids were found in the cheese of FL fed animals. The substitution of soybean meal by flaxseed and lupins in diets of Holstein cows warrants further investigation, especially towards the production of cheese that meet the consumers' demand for novel and healthier dairy products.

Automated summary

In Mediterranean countries, using locally produced flaxseed and lupins as a partial substitute for soymeal in dairy cow feed can positively affect milk yield and cheese production. This alternative feed does not impact the general health and milk yield of the cows, but it does result in milk and cheese with improved fatty acid profiles that are beneficial to human health. Overall, the substitution of soymeal with flaxseed and lupins is profitable and provides special characteristics to milk and cheese.