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Our study evaluated the impact of incorporating flax seeds or a flax and mustard seeds' mixture into goats' diets to enhance milk polyunsaturated fatty acids (PUFAs). The incorporation of mustard seeds also aimed to slow the lipid oxidation process. A three-week feeding trial was conducted on 18 lactating goats, randomly distributed in three groups: control (C), FS (replacing 12% of the oil source with flax seeds), and FMS (replacing a quarter of flax seeds with mustard seeds). Flax seed inclusion improved the quality of milk fat by reducing saturated fatty acid concentration (p = 0.004) and increasing PUFA levels (p = 0.001). Both experimental groups significantly lowered the omega 6/omega 3 fatty acid ratio (p < 0.001). The FMS group showed a significantly higher total vitamin E concentration (p = 0.007). The fat oxidation parameters revealed that after 24 h of storage at room temperature, the p-anisidine value increased for the FS group compared to the C group, while the FSM group showed no significant difference, suggesting that the combined inclusion of flax and mustard seeds may prolong milk storage time by mitigating secondary oxidation products. This highlights the potential benefits of incorporating the studied seeds into goats' diets for improving milk quality and extending its shelf life. [ABSTRACT FROM AUTHOR]

Brewer's spent yeast (BSY) is a byproduct of the beer industry, rich in proteins and bioactive compounds. The effects of BSY were investigated through a 6-week feeding trial on 30 lactating dairy Blackhead sheep (54.7 ± 5.66 kg, 177.34 days in milk) distributed under a completely randomised design in two groups: a control group (with soybean meal and sunflower meal as protein sources), and a BSY group, where soybean meal was totally replaced by BSY (5.4% inclusion, DM basis). The inclusion of BSY led to a 25% decrease in ruminal propionate and in the acetate/propionate ratio. BSY influenced the milk fatty acid profile by significantly decreasing the omega 6: omega 3 ratio and increasing the contents of caproic, capric, and lauric acids. Also, the inclusion of BSY was associated with an increase in the milk's total polyphenols. Consistently, determinations of the parameters of the milk fat's oxidative stability revealed a decrease in conjugated diene contents. Moreover, the mineral contents of milk were influenced, with an increase in Ca content noted. Overall, these results indicate that BSY represents an alternative feedstuff for ruminants' nutrition, which could have the potential to induce changes in ruminal fermentation and milk composition that are beneficial for consumers. [ABSTRACT FROM AUTHOR]

Having a complex fatty acid profile, milk is the subject of several oxidation processes that are different to those in other food matrices. Considering this, is important to appreciate the degradation status of milk using rapid and simple methods to quantify the main degradation products. The aim of this study was to adapt a simple and rapid method for determination of milk oxidative stability and to quantify malondialdehyde, one of the lipid oxidation products. Four parameters (trichloroacetic acid concentration—TCA, antioxidant type, incubation time, and thiobarbituric acid—TBA concentration) were modified to establish the best experimental sequence. It was concluded that the relevant results were obtained by precipitating milk proteins using 20% TCA; incubating samples for 90 min with 0.8% TBA, without adding antioxidant; and registering absorbance at three different wavelengths (450, 495, and 532 nm). This method was successfully applied to cow and sheep milk samples and the absorbance values obtained provided information about degradation of fatty acids for both milk types. The Pearson correlation showed a positive relationship between the fatty acid profiles of milk samples and the absorbance values that characterized their oxidation pattern during storage. [ABSTRACT FROM AUTHOR]

BACKGROUND The effect of a diet containing 15% grape pomace ( GP) on the general health status and milk quality of dairy cows was assessed by plasma biochemistry and total polyphenol ( TP) content, milk polyphenols, milk composition and milk protein fractions. RESULTS Among the polyphenols measured by liquid chromatography-mass spectroscopy in GP, in feed containing GP ( GP+) or not containing GP ( GP-), gallic acid and epicatechin were present in the highest concentrations (67.58 and 19.23 µg mL−1, respectively). Higher amounts of TP were also detected in the blood plasma of GP+ cows (114.06 and 83.93 mg GAE L−1, respectively) but not in their milk (233.17 and 245.75 mg GAE L−1, respectively). Also a significant increase was found for lactose and β-lactoglobulin, although there was no effect on α-lactalbumin, albumin, secretory components and caseins. CONCLUSION Inclusion of 15% GP in the diets of dairy cows is beneficial for overall normal blood constituent metabolism and helps to maintain cow health. The milk of cows fed with a GP diet preserves the normal levels of fat, protein and caseins, and has increased levels of components that make this milk a versatile ingredient material for the food industry (e.g. model whey powders, stability of lactose-rich powders). © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]