Effect of Linoleic and Linolenic Acid Contents on the Oxidation Stability of Interesterified Fats under Rancimat Test Conditions.

This study aimed to better understand the association between the amount of polyunsaturated fatty acids, namely, linoleic acid (LA) and linolenic acid (LNA), and the increases in the peroxide value that results from storing interesterified fats, which are used as sources of solid fats in edible oil and fat products, at high temperatures. Six interesterified fats with different LA and LNA contents were prepared and oxidized at 50°C, 60°C, 70°C, and 80°C under Rancimat test conditions. The oxidation rate increased with LA and LNA contents and increasing temperature. The oxidation kinetic analysis during the early oxidation stages demonstrated that when LA and LNA exceeded 8% and 2% respectively, the oxidative stability decreased as expected. However, the total LA and LNA contents had a higher correlation with the reaction rate constant [k (meq kg-1 h-1 )] than each amount of LA and LNA contained therein. In other words, the oxidation stability of the interesterified fats used in this study depended on the total LA and LNA contents.

Effect of Sucrose Esterified Fatty Acid Moieties on the Crystal Nanostructure and Physical Properties of Water-in-oil Palm-based Fat Blends.

The effects of sucrose ester of fatty acid (SEF) on the nanostructure and the physical properties of water-in-oil (W/O)-type emulsified semisolid fats were investigated. Model emulsions including palm-based semisolid fats and fully hydrogenated rapeseed oils with 0.5% SEF or fractionated lecithin, were prepared by rapidly cooling crystallization using 0.5% monoacylglycerol as an emulsifier. The SEFs used in this study were functionalized with various fatty acids, namely, lauric, palmitic, stearic, oleic, and erucic acids. Cryogenic transmission electron microscopy (cryo-TEM) was used to observe the sizes of the solvent- extracted nanoplatelets. The solid fat content (SFC), oil migration value, and storage elastic modulus were also determined. The average crystal size, which was measured in length, of the fat blends with SEFs containing saturated fatty acids (namely, palmitic and stearic acids) was smaller than that of the SEFs containing unsaturated fatty acids (namely, oleic and erucic acids). The effects exerted by these fatty acid moieties on the spherulite size in the corresponding bulk fat blends were observed via polarized microscopy (PLM). The results suggest that nanostructure formation upon the addition of SEF ultimately influenced these aggregated microstructures. Generally, smaller platelets resulted in higher SFC in the fat phase, and a high correlation between the SFC and the G' values in W/O emulsion fats was observed (R2 = 0.884) at 30°C. In contrast, the correlation was low at 10℃. Furthermore, samples with larger nanocrystals had a higher propensity for oil migration. Thus, the addition of SEF regulated the fat crystal nanostructure during nucleation and crystal growth, which could ultimately influence the physical properties of commercially manufactured fat products such as margarine.

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.

Nanostructured Fat Crystal and Solid Fat Content Effects on the Physical Properties of Water-in-Oil Semisolid Fat Blends.

The effect of nanostructured fat crystals on oil migration properties in water-in-oil-type emulsified semisolid fats was investigated. Model emulsions containing 4 different semisolid fats (palm oil, partially hydrogenated palm oil, partially hydrogenated soybean oil, and milk fat) and 1 bulk fat blend were prepared with rapidly cooling crystallization. The length of the nanoplatelets was observed by cryo transmission electron microscopy, the crystal thickness was calculated by small-angle X-ray diffraction, and the solid fat content (SFC) was determined. Although the interfacial surface of the dispersed water droplets did not influence nanoplatelet size, oil migration in the emulsified samples was lower than in the bulk fat. The crystal sizes in samples with partially hydrogenated soybean oil involving elaidic acid were larger, in contrast to that of milk fat, involving low to medium chain length fatty acids, which had smaller crystal sizes and showed wide length distribution. The length of the platelets and SFC were related to the oil migration value. These results suggest that the oil binding ability of fat products, such as margarine, is influenced by the nanostructure, which is related to fatty acid composition and interfacial structure.