Antioxidant activity toward fish oil triacylglycerols exerted by sphingoid bases isolated from butter serum with α-tocopherol.

A mixture of sphingoid bases (SPGs) was prepared from butter serum, a by-product of anhydrous milk fat production. The mixture comprised seven types of SPGs with C16 to C19 alkyl chains. These milk SPGs inhibited the oxidation of fish oil triacylglycerol (TAG) more effectively than did a standard SPG (d18:1) with α-tocopherol. Reaction products were prepared from the combination of d18:0 or d18:1 with acrolein and propanal. Both sets of reaction products showed antioxidant activity toward fish oil TAG. Antioxidant activity of reaction products from d18:0 was stronger than that of reaction products from d18:1, suggesting that the molecule d18:0 may be a significant focus of the difference in antioxidant activity between milk SPGs and d18:1. To use SPGs as food additives in the future, an appropriate source of SPGs will be needed, and butter serum appears to have promise as a source of functional SPGs with strong antioxidant activity.

Association of DHA Concentration in Human Breast Milk with Maternal Diet and Use of Supplements: A Cross-Sectional Analysis of Data from the Japanese Human Milk Study Cohort.

BACKGROUND: DHA (22:6n-3) is essential for neurodevelopment in children, and its concentration in human breast milk is historically high in Japan. Dietary patterns in Japan might affect the fatty acid (FA) composition among lactating mothers. OBJECTIVES: This study aimed to characterize the composition of milk FAs and to identify any dietary and sociodemographic factors associated with the variability of DHA concentration in breast milk in the Japanese population. METHODS: This cross-sectional study was performed as part of the Japanese Human Milk Study. Milk FAs were analyzed by GC at 1-6 mo postpartum, and maternal diet was estimated using an FFQ, including 11 types and cooking methods of seafoods, and the use of DHA supplements. The association of milk DHA with maternal diet and sociodemographic factors was investigated. RESULTS: Milk FA concentrations were measured in 78 mothers, including 24 who routinely used DHA supplements. The DHA concentration in milk (overall median: 0.62%; IQR: 0.47%-0.78%) was higher in women who took DHA supplements than in women who had never used DHA supplements (0.74%compared with 0.55%; P = 0.011). A linear regression model showed the association of milk DHA concentration with maternal dietary intake of grilled fish (ß ± SE: 0.006 ± 0.003; standardized ß: 0.234; r 2 = 0.232, P = 0.036) after adjustment for DHA supplementation status, maternal and infant age, maternal BMI, and infant birth weight. Other FA concentrations were consistent, whereas caproic acid (6:0), undecylic acid (11:0), pentadecylic acid (15:0), palmitoleic acid (16:1n-7), and vaccenic acid (18:1n-7) varied by DHA supplementation status. CONCLUSIONS: The DHA concentration in human milk may be influenced by maternal grilled fish consumption and frequent DHA supplementation in lactating Japanese women. Milk DHA concentrations may reflect a dietary habit in Japanese mothers.This trial was registered at www.umin.ac.jp/ctr as UMIN000015494.

Rennet-induced aggregation and curd formation from skimmed milk powders prepared under different sterilizing conditions.

Heat treatment during the production of skimmed milk powder causes denaturation of proteins, thereby affecting the physicochemical properties of the skimmed milk powder. To understand the effects of heat treatment on the sensitivity of the casein micelles in skimmed milk powders, low heating type (L), normal heating type (N), high heating type (H), and super-high heating type (SH), to reaction with rennet, rennet-induced curd formation was investigated. A well-developed network structure with wide spaces was observed only in the curd derived from the solution of type L skimmed milk powder. SDS-PAGE suggested that there was no difference in the amount of glycomacropeptide generated from kappa-casein in the four types of skimmed milk powder, but casein micelles in the solution of type L skimmed milk powder formed aggregates most effectively. These results are discussed with respect to the thermal denaturation of proteins in skimmed milk powder.