Technical note: Simultaneous carotenoid and vitamin analysis of milk from total mixed ration-fed cows optimized for xanthophyll detection

Xanthophylls in Human Milk and Maternal Diet: A Cross-sectional Analysis of Data from the Japanese Human Milk Study Cohort

Background

Maternal diet and sociodemographic factors influence xanthophyll concentration and composition in human milk. However, the importance of dietary patterns regarding the intake of fruits, vegetables, and xanthophylls remains unclear.

Objective

The aim was to determine the composition of xanthophylls in the human milk of Japanese mothers and explore associations of xanthophylls with dietary and sociodemographic factors.

Methods

This cross-sectional study was conducted in the early phase of the Japanese Human Milk Study. Xanthophyll content was measured using liquid chromatography at 30-36 d postpartum. Maternal intake of foods, nutrients, and dietary supplements was estimated using a food-frequency questionnaire. Linear regression models were established using xanthophylls, maternal diet, and sociodemographic factors.

Results

Xanthophyll concentrations were measured in human milk from 118 mothers. The xanthophyll concentration varied among individuals. The median (IQR) concentrations of lutein, zeaxanthin, and β-cryptoxanthin were 65.6 ng/mL (51.6-103.4 ng/mL), 18.6 ng/mL (12.9-25.8 ng/mL), and 15.6 ng/mL (9.0-26.0 ng/mL), respectively. In multivariate models, the lutein concentration was associated independently with dietary green vegetables, exclusive breastfeeding, and education (r 2 = 0.153 for the model; β ± SE: 0.468 ± 0.198, 25.048 ± 10.222, and 13.460 ± 6.774; standardized β = 0.210, 0.217, and 0.175; P = 0.019, 0.016, and 0.049 for dietary green vegetables, exclusive breastfeeding, and education, respectively). For zeaxanthin, exclusive breastfeeding was the most appropriate predictor (r 2 = 0.085; β ± SE: 7.811 ± 3.300; standardized β = 0.218; P = 0.020). The highest predictive power for human milk β-cryptoxanthin was obtained with dietary β-cryptoxanthin (r 2 = 0.258; β ± SE: 0.089 ± 0.015; standardized β = 0.468; P < 0.001), attributed to maternal citrus intake.

Conclusions

β-Cryptoxanthin in human milk was the xanthophyll most influenced by the maternal diet in Japanese women. The β-cryptoxanthin concentration in human milk was reflected by the maternal β-cryptoxanthin intake, mainly attributed to Japanese citrus consumption. This trial was registered in the Japanese Clinical Trials Registry (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000017649) as UMIN000015494.

A Fast and Efficient Ultrasound-Assisted Extraction of Tocopherols in Cow Milk Followed by HPLC Determination

A fast HPLC method with fluorescence detector (FD) was developed for the determination of three tocopherols (TOCs) in milk samples from Modicana cattle breed. The ultrasound-assisted procedure was optimized for the extraction of TOCs prior to HPLC/FD analysis, reducing sample preparation time and allowing a fast quantification of α-tocopherol, δ-tocopherol and γ tocopherol. The optimized ultrasonic extraction combines an efficient and simple saponification at room temperature and a rapid HPLC quantification of TOCs in milk. The precision of the full analytical procedure was satisfactory and the recoveries at three spiked levels were between 95.3% and 87.8%. The linear correlations were evaluated (R² > 0.99) and the relative standard deviation (RSD) values for intra-day and inter-day tests at three spiked levels were below 1% for the retention time and below 5.20% for the area at low level spiking. The proposed procedure, reducing the experimental complexity, allowed accurate extraction and detection of three TOCs in milk samples from Modicana cattle breed.

Effects of the substitution of soybean meal by spirulina in a hay-based diet for dairy cows on milk composition and sensory perception

The demand for protein sources alternative to soybean meal for supplementing forages low in metabolizable protein is large. The suitability of spirulina (Arthrospira platensis), a fast growing and resource-efficient blue-green microalga, as a source of metabolizable protein for dairy cows is known, but its effects on milk antioxidants and sensory properties were never investigated. Twelve cows were allocated to 2 groups and fed hay-based diets complemented with sugar beet pulp and wheat flakes in individual feeding troughs. The N content per kilogram of DM was equivalent between the 2 diets. Diet of 1 group was supplemented with 5% spirulina; the second group was supplemented with 6% soybean meal (control). After an adaptation period of 15 d, data were collected, and feed, milk, blood, and rumen fluid were sampled. Feeds were analyzed for proximate contents, and blood plasma was analyzed for total antioxidant capacity and antioxidant contents (tocopherol, phenols). Milk samples were analyzed for fatty acid profile, coagulation properties, color, and contents of fat, protein, lactose, total phenols, lipophilic vitamins, and provitamins (e.g., β-carotene). Triangle tests were performed by a trained sensory panel on 6 homogenized and pasteurized bulk milk samples per treatment. The substitution of soybean meal by spirulina in the diet did not affect feed intake, milk yield, milk fat, protein, or lactose contents compared with the control group. However, the milk from the spirulina-fed cows had a higher content of β-carotene (0.207 vs. 0.135 μg/mL) and was more yellow (b* index: 14.9 vs. 13.8). Similar to the spirulina lipids but far less pronounced, the milk fat from the spirulina-fed cows had a higher proportion of γ-linolenic acid (0.057 vs. 0.038% of fatty acid methyl esters) compared with milk fat from soybean meal-fed cows. Also trans-11 C18:1 (vaccenic acid) and other C18:1 trans isomers were elevated, but otherwise the fatty acid profile resembled that of cows fed the control diet. No sensory difference was found between milk from the 2 experimental groups. Furthermore, we observed no effects of substituting soybean meal by spirulina on total antioxidant capacity, α-tocopherol and total phenols in blood and milk. Effects on rumen fluid characteristics were minor. In conclusion, spirulina seems to be a promising protein source for dairy cows with certain improvements in nutritionally favorable constituents in milk and without side-effects on animal performance in the short term.