Ya-Wei Fan

Evaluating the trans Fatty Acid, CLA, PUFA and Erucic Acid Diversity in Human Milk from Five Regions in China

Human milk was obtained from 97 healthy lactating women from five different regions in China. Twenty-four hour dietary questionnaire identified the foods consumed that showed distinct differences in food types between cities. The southern and central regions had higher levels of total trans fatty acids (TFA) and conjugated linoleic acids (CLA) in human milk than the northern region. The major isomers in human milk from the northern region were vaccenic and rumenic acids, whereas the other regions had a random distribution of these isomers. This was consistent with the isomer distribution in the refined vegetable oils used and their increased formation during high temperature stir-frying. The human milk composition showed little evidence that partially hydrogenated fats were consumed, except eight mothers in Guangzhou who reported eating crackers, plus four other mothers. The TFA concentration in these human milk samples was higher (2.06–3.96%). The amount of n-6 (1.70–2.24%) and n-3 (0.60–1.47%) highly unsaturated fatty acids (HUFA) in human milk and the resultant ratio (1.43–2.95) showed all mothers in China had an adequate supply of HUFA in their diet. Rapeseed oil was consumed evidenced by erucic acids in human milk. The levels of erucic acid were below internationally accepted limits for human consumption. The levels of undesirable TFA and CLA isomers in human milk are a concern. Efforts to decrease the practice of high temperature stir-frying using unsaturated oils, and a promotion to increase consumption of dairy and ruminant products should be considered in China.

Erythrocyte membrane trans-fatty acid index is positively associated with a 10-year CHD risk probability.

Industry-generated trans-fatty acids (TFA) are detrimental to risk of CHD, but ruminant-originated TFA have been reported as neutral or equivocal. Therefore, the total TFA amount should not be the only factor considered when measuring the effects of TFA. In the present study, we addressed whether a version of the TFA index that unifies the effects of different TFA isomers into one equation could be used to reflect CHD risk probability (RP). The present cross-sectional study involved 2713 individuals divided into four groups that represented different pathological severities and potential risks of CHD: acute coronary syndrome (ACS, n 581); chronic coronary artery disease (CCAD, n 631); high-risk population (HRP, n 659); healthy volunteers (HV, n 842). A 10-year CHD RP was calculated. Meanwhile, the equation of the TFA index was derived using five TFA isomers (trans-16 : 1n-7, trans-16 : 1n-9, trans-18 : 1n-7, trans-18 : 1n-9 and trans-18 : 2n-6n-9), which were detected in the whole blood, serum and erythrocyte membranes of each subject. The TFA index and the 10-year CHD RP were compared by linear models. It was shown that only in the erythrocyte membrane, the TFA isomers were significantly different between the groups. In the ACS group, industry-generated TFA (trans-16 : 1n-9, trans-18 : 1n-9 and trans-18 : 2n-6n-9) were the highest, whereas ruminant-originated TFA (trans-16 : 1n-7 and trans-18 : 1n-7), which manifested an inverse relationship with CHD, were the lowest, and vice versa in the HV group. The TFA index decreased progressively from 7·12 to 5·06, 3·11 and 1·92 in the ACS, CCAD, HRP and HV groups, respectively. The erythrocyte membrane TFA index was positively associated with the 10-year CHD RP (R 2 0·9981) and manifested a strong linear correlation, which might reflect the true pathological severity of CHD.

Analysis of nonpolar lipophilic aldehydes/ketones in oxidized edible oils using HPLC-QqQ-MS for the evaluation of their parent fatty acids

Six edible oils with different fatty acid compositions were used to explore nonpolar lipophilic aldehydes/ketones produced by possible parent fatty acids after accelerated oxidation. Simultaneous determination of 20 aldehydes and five ketones within the C2-C10 range was carried out using HPLC-QqQ-MS technique. Close relationships among the amounts of aldehyde carbonyls and the initial contents of oleic, linoleic and α-linolenic acids were revealed by principal component analysis. Pentanal, hexanal, hexanone, heptanal, 2-propenal, 2-heptenal, 2-octenal, 2-nonenal and 2,4-decadienal were the key carbonyls in close association with the initial content of linoleic acid. Ethanal, acetone, propanal, butanal, 2-pentenal, 2-hexenal, 2,4-heptadienal and 2,4-nonadienal were the key markers closely related with the initial content of α-linolenic acid. Furthermore, octanal, octanone, nonanal, nonanone, decanal, decanone and 2-decenal were the oxidation indexes linked to the initial content of oleic acid. The results provide a complete picture of secondary oxidation products in edible oils and possible source of parent fatty acids.

Comparison of Oxidative Stability among Edible Oils under Continuous Frying Conditions

The stability of camellia oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 1:7:1) after frying potatoes was compared with palm oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 4:4:1) and peanut oil (saturated fatty acid: monounsaturated fatty acid: polyunsaturated fatty acid = 2:4:4). Oil samples were evaluated for acid value, iodine value, peroxide value, p-anisidine value, total oxidation value, tocopherols content, and fatty acids composition. There was the least change in fatty acid composition in camellia oil among the three edible oils. The α-tocopherol was more vulnerable to heat degradation than γ-tocopherol and δ-tocopherol, and α-tocopherol was completely degraded before the whole frying process was done for palm and peanut oils. The oxidative stabilities of the three edible oils were in the order of camellia oil > palm oil > peanut oil. The oxidative stability was mainly determined by the calculated oxidizability value related to fatty acid composition, and when calculated oxidizability values were similar, the tocopherol contents of edible oils would be a key factor in affecting their oxidative stabilities.

Alteration on phenolic acids and the appearance of lotus (Nelumbo nucifera Gaertn) seeds dealt with antistaling agents during storage

ABSTRACT This study evaluated the preservation effectiveness of selected antistaling agents on lotus seeds (Nelumbo nucifera Gaertn) status and the alteration of phenolic acids during their storage. Ascorbic acid (AA), benzoic acid (BA), sodium hydrogen sulfite (SHS), BA+ AA and SHS+ AA were identified as effective to keep lotus seeds fresh with the order of SHS+ AA > BA+ AA > AA > SHS > BA in terms of general performance on not-browning degree, microorganism contamination status, sensory evaluation, and the protection of polyphenols against being oxidized. The polyphenols determined by HPLC and HPLC-MS in lotus seeds were mainly gallic, chlorogenic, gentisic, caffeic, cinnamic, p-coumaric, ferulic, rosmarinic, and salicylic acids. Chlorogenic, gentisic, and caffeic acids were the main phenolic acids correlated with oxidative browning. SHS+ AA was found on inhibiting chlorogenic acid oxidized (p < 0.05) as well as SHS or AA did. BA+ AA also had protective effect on all these three phenolics. The increment of gallic, caffeic, chlorogenic, and p-coumaric acids at the beginning of storage, which was from the hydrolyzation of glycosides promoted by BA, had accordance with the deteriorate sensory of lotus seeds and led to worse anti-browning effect. Gallic acid was found to be relevant to the degree of microorganism contamination. The stronger antibacterial capacity antistaling agents had, the later regeneration of gallic acid appeared. In conclusion, the selected antistaling agents had different preservation effectiveness, which would synchronously indicate alteration of relevant phenolic acids profiles of lotus seed during storage.