A comparative study of the composition of triacylglycerol molecular species in equine and human milks

Human milk phospholipid analog improved the digestion and absorption of 1,3-dioleoyl-2-palmitoyl-glycerol

The present study investigated the effects of a human milk phospholipid analog (HPLA) on the digestion and absorption of 1,3-dioleoyl-2-palmitoyl-glycerol (OPO). The HPLA contained 26.48% phosphatidylethanolamine (PE), 24.64% phosphatidylcholine (PC), 36.19% sphingomyelin (SM), 6.35% phosphatidylinositol (PI), and 6.32% phosphatidylserine (PS), with 40.51% C16:0, 17.02% C18:0, 29.19% C18:1, and 13.26% C18:2. The HPLA prevented OPO from hydrolysis during the in vitro gastric phase, while it facilitated the digestion of OPO during the in vitro intestinal stage, resulting in the production of large amounts of diglycerides (DAGs) and monoglycerides (MAGs). In vivo experimental results showed that the HPLA might increase the gastric emptying rate of OPO and increase the hydrolysis and absorption of OPO at an early stage of intestinal digestion. Notably, fatty acids in the serum of the OPO group decreased to their initial value at 5 h, while the serum of the OPO + HPLA (OPOH) group still contained a high level of fatty acids indicating that the HPLA was helpful in maintaining serum lipid at a high level, which might be beneficial for sustainably providing energy for babies. The present study provides data support for the potential application of Chinese human milk phospholipid analogs in infant formulas.

A novel and controllable method for simultaneous preparation of human milk fat substitutes (OPL, OPO and LPL): two-step enzymatic ethanolysis-esterification strategy

A novel and effective approach based on the two-step ethanolysis-esterification strategy was proposed for the controllable and simultaneous preparation of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL), 1,3-dioleoyl-2-palmitoyl-glycerol (OPO) and 1,3-dilinoleoyl-2-palmitoyl-glycerol (LPL) with adjustable proportions. Enzymatic ethanolysis of fractionated palm stearin was carried out to yield 2-monopalmitoylglycerol (79.4 ± 0.6 %) with over 91.0 % purity at the optimal conditions. The immobilized Candida sp. lipase (CSL) on octyl-functionalized ordered mesoporous silica (OMS-C₈) was applied to re-esterify 2-monopalmitoylglycerol with oleic acid and linoleic acid for the simultaneous production of OPL, OPO, and LPL. The total content in the final products was 81.5 %, with 91.3 % of palmitic acid (PA) content at the sn-2 position. Besides, OPL/OPO/LPL was conveniently prepared with suitable proportions for worldwide infants by adjusting the ratio of acyl donors. This paper provides a novel and effective two-step ethanolysis-esterification strategy for the development of human milk fat substitutes (HMFS).

Medium- and long-chain triacylglycerols and di-unsaturated fatty acyl-palmitoyl-glycerols in Chinese human milk: Association with region during the lactation

The triacylglycerols (TAGs) of medium- and long-chain triacylglycerols (MLCT) and di-unsaturated fatty acyl-palmitoyl-glycerols (UPU) in human milk provide better nutritional effects, and should be prioritized as crucial focuses on neonatal nutrition research. However, little has been done on the influences of the lactation stage and regional diversity on MLCT and UPU. In this study, we collected 204 human milk samples during colostrum, 1st and 4th month from the north (Baotou), central (Beijing), east (Jinan), southwest (Kunming), southeast (Shenzhen), and northwest (Xining) regions of China. There were 122 species of TAGs detected with UPLC-Q-TOF-MS, including 60 kinds of MLCT and 15 kinds of UPU. The MLCT and UPU type TAGs in human milk were ~27 and ~38%, respectively. The sum content of MLCT and UPU in human milk was stable. Compared to the regional diversity, lactation stages showed more obvious influences on MLCT and UPU composition. Moreover, a summary of TAG studies indicated that Chinese human milk showed a higher ratio of O-P-L to O-P-O than in western countries.

Macronutrient content and fatty acid composition and their positional distribution in human breast milk from Zhejiang Province, China in different lactation periods

Lactational changes in macronutrient content, lipid profile, fatty acid composition, and positional distribution of human breast milk were investigated in this study. A total of 378 milk samples of six different lactation periods, including 0‒5, 6‒14, 15‒30, 31‒90, 91‒180, and 181‒360 days, were collected cross-sectionally from healthy lactating women in Zhejiang, China. As lactation progressed from 0‒5 to 15‒30 days, the lipid content and the percentages of C10:0, C12:0, C14:0, C18:2n-6, and C18:3n-3 increased significantly, while the protein concentration and the proportions of phospholipids, cholesterols, C16:0, C18:1n-9, C24:1n-9, C20:4n-6, C22:4n-6, C22:5n-3, and C22:6n-3 decreased notably. When lactation was further extended to 181‒360 days, the protein content continued to decrease, and the percentages of C12:0 and C14:0 continued to increase, whereas the levels of other tested nutrients remained stable. Although the triacylglycerol positional distributions of some fatty acids underwent significant lactational variations, C14:0, C16:0, C24:1n-9, C22:4n-6, C22:5n-3, and C22:6n-3 were located mainly at the sn-2 position, while C18:1n-9, C18:2n-6, and C18:3n-3 were primarily distributed at the sn-1,3 positions. Compared with human breast milk reported in Western countries, samples in our study demonstrated higher percentages of C18:2n-6, C18:3n-3, C20:4n-6, and C22:6n-3, but lower proportions of C12:0, C14:0, and C18:1n-9. The results from this study indicated a nutritional composition different from that of the Western countries and may provide useful data for the development of infant formulas closer to Chinese breast milk in terms of the fatty acid composition and its specified positional distribution on triglyceride structure.

Effects of the Major Structured Triacylglycerols in Human Milk on Lipid Metabolism of Hepatocyte Cells in Vitro

The effect of structured triacylglycerols [1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL), 3-dilinoleoyl-2-palmitoylglycerol (LPL), and 1,3-dioleoyl-2-palmitoylglycerol (OPO)] in human milk on the lipid metabolism was unclear. Hence, this study investigated the effects of different structured triacylglycerols and their mixtures (M) (OPL/LPL/OPO in M1, M2, and M3 were 1.5:0.5:1, 1.2:1.2:1, and 0.5:0.2:1, respectively) on lipid and expression levels of some critical proteins involved in lipid metabolism in LO2 cells. Results showed that there was more lipid accumulation in the LO2 cells exposed to 2,3-dioleoyl-1-palmitoylglycerol (POO) than OPL, LPL, and OPO (p < 0.05), and more lipid accumulation was observed in the OPL group compared to LPL and OPO groups (p < 0.05). Moreover, there was more lipid accumulation in the M3 group compared to M1 and M2 groups. The expression level of diacylglycerol acyltransferase was highest in the POO group compared to LPL, OPO, and OPL groups and was higher in the M3 group than M1 and M2 groups. The expression levels of acetyl-CoA carboxylase 1 and long-chain acyl-CoA synthetase 1 were highest in the OPL group compared to OPO and LPL groups. In comparison to OPO and LPL, OPL seemed to be more likely to increase the content of triacylglycerols and cholesterol in LO2 cells; therefore, whether this was beneficial to the growth and development of infants needs further verification.

Human Milk sn-2 Palmitate Triglyceride Rich in Linoleic Acid Had Lower Digestibility but Higher Absorptivity Compared with the sn-2 Palmitate Triglyceride Rich in Oleic Acid in Vitro

The digestion and absorption of different structural lipids in human milk may be different. Hence, by simulating in vitro infant digestion and Caco-2 cells to explore the effects of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL)/1,3-dilinoleoyl-2-palmitoylglycerol (LPL)/1,3-dioleoyl-2-palmitoylglycerol (OPO) and their mixtures (M) (OPL/LPL/OPO in M1, M2, and M3 were 1.5/0.5/1, 1.2/1.2/1, and 0.5/0.2/1, respectively) on digestion and absorption. The digestibility of the OPO group was higher than those of the OPL and LPL groups, and the M3 group was higher than the M1 and M2 groups. The synthesis and transport of triglycerides in Caco-2 cells in OPL and LPL groups were higher than the OPO group, and the M1 group was significantly higher than that of M3. The expression of FABP1, PPARα, and MTT protein in OPL and M1 groups was significantly higher than OPO and M3, respectively. There are differences in the digestion and absorption of differently structured lipids from this study.

An Integrative Approach of an In Vitro Measurement of the Digestibility of Triacylglycerols of Human Milk

Several studies have been published regarding the effect of different factors on the digestion of milk lipids, considering their natural structural arrangement as milk fat globules and the efficiency of the digestive enzymes in the lipolysis of such complex structures. During digestion, the lipolytic products are dispersed in vesicles and micelles, which are the source for absorption of digested lipids. Therefore, it is necessary to consider the isolation of the micellar phase from the digesta to appropriately determine the amounts and classes of lipids which are bioaccessible. This study presents an integrative approach that included an isolation procedure to separate the micellar fraction from undigested and non-micellar parts, and the distribution of digested milk lipids in micelles determined directly through chromatographic techniques. Four groups of five full term mothers donated colostrum or mature milk. Two sets of samples were analyzed directly (raw), and two sets were pasteurized and then analyzed. Our data revealed that the profile of digested milk lipids is different depending on the lactation period and processing stage, while the carbon atom number distribution of the digested triacylglycerols in the micellar fraction provides a substantial information regarding the acylglycerols species that are less available for absorption.

Lipidomic analysis of lactic acid bacteria strains by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Analysis by MALDI-TOF mass spectrometry and gas chromatography-mass spectrometry was used to characterize the lipid profile of 3 lactic acid bacteria strains. By gas chromatography coupled with mass spectrometry, 23 fatty acids were identified. Dominant acids were palmitic (C16:0), oleic (C18:1), and α-linoleic acid (C18:3n-3) for Lactobacillus paracasei; for Lactococcus lactis they were palmitic (C16:0), gondoic (C20:1), myristoleic (C14:1), and eicosadienoic acid (C20:2), respectively; and in the case of Lactobacillus curvatus were C18:1, C18:2n-6, and C16:0, respectively. The effect of the medium on fatty acid composition was also determined. In addition, the fatty acid profile was also compared using MALDI MS analysis. The MALDI-TOF MS was used for qualitative analysis and identification of bacterial lipids. Phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylcholine, triacylglycerols, and ceramides were the most abundant species in lactic acid bacteria. One hundred different combinations of fatty acids in polar and nonpolar lipids have been identified, including 11 phospholipids (18 phosphatidylglycerol, 16 phosphatidylethanolamine, 10 phosphatidylinositol, 8 phosphatidylcholine, 4 lyso-phosphatidylethanolamine, 3 lyso-phosphatidylcholine, 3 phosphatidylserine, 1 lyso-phosphatidic acid, 1 lyso-phosphatidylglycerol, 1 lyso-phoshatidylinositol, and 1 phosphatidic acid), 23 triacylglycerols, 9 ceramides, and 2 sphingomyelin. The most abundant fatty acids identified were C16:0, C16:1, C18:0, and C18:3. Obtained lipid profiles allowed to distinguish the tested bacterial strains.

Facile and Green Production of Human Milk Fat Substitute through Rhodococcus opacus Fermentation

Human milk fat substitute (HMFS) is a class of structured lipids widely used in infant formulas. Herein, HMFS was prepared by Rhodococcus opacus fermentation. The substrate oils suitable for HMFS production were coconut oil (66.1-57.5%), soybean oil (17.5-26.5%), high oleic acid sunflower oil (5.4-4.5%), Antarctic krill oil (9-9.5%), and fungal oil (2%). Six HMFSs were prepared, among which HMFS V and VI were similar to human milk fat from Chinese in terms of fatty acid composition and triacylglycerol species. The sn-2 position of HMFS was occupied by palmitic acid (49.31 and 43.48% in HMFS V and VI, respectively). The major triacylglycerols were OPL, OPO, and LPL, accounting for 15.90, 9.49, and 6.84 and 17.52, 8.44, and 8.55% in HMFS V and VI, respectively. This study is the first to prepare structured lipids intended for infant formula through fermentation, providing a novel strategy for the edible oil industry.

Lipidome analysis of milk composition in humans, monkeys, bovids, and pigs

Background

Lipids contained in milk are an essential source of energy and structural materials for a growing neonate. Furthermore, lipids’ long-chain unsaturated fatty acid residues can directly participate in neonatal tissue formation. Here, we used untargeted mass spectrometric measurements to assess milk lipid composition in seven mammalian species: humans, two macaque species, cows, goats, yaks, and pigs.

Results

Analysis of the main milk lipid class, triacylglycerides (TAGs), revealed species-specific quantitative differences in the composition of fatty acid residues for each of seven species. Overall, differences in milk lipid composition reflect evolutionary distances among species, with each species group demonstrating specific lipidome features. Among them, human milk contained more medium and long-chain unsaturated fatty acids compared to other species, while pig milk was the most distinct, featuring the highest proportion of long-chain polyunsaturated fatty acids.

Conclusions

We show that milk lipidome composition is dynamic across mammalian species, changed extensively in pigs, and contains features particular to humans.

Comprehensive Characterization of Bovine Milk Lipids: Triglycerides

A comprehensive survey on triglycerides (TAGs) of bovine milk was conducted by a combination of exhaustive liquid chromatography (LC) separation, high-resolution mass spectrometry (MS) detection, and automated lipid molecular feature extraction. A total of 220 groups (a series of species having the same chemical formula and mass) and 3454 molecular species of TAGs were identified based on the accurate mass of the parent ion as well as MS2 information. Sixty-five different fatty acids (FAs) were found across these TAG species; C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C16:0, C18:0, and C18:1 were the most frequent FAs, whereas C11:3, C11:4, C27:0, C27:1, C28:0, and C28:1 were rare FAs in TAG molecules. The number of species identified represents only a small portion of total TAG molecules that can be theoretically synthesized from 65 FAs. Each TAG group contains on average 15-16 isomeric species (species with different FA composition), but positional isomers do not seem to be widespread. As the isomeric species cannot be completely resolved chromatographically, quantification of TAG was conducted at the group level. The most abundant TAG groups in bovine milk include TAG 34:0, TAG 36:0, TAG 38:1, TAG 38:0, and TAG 40:1. This study provides the most comprehensive milk TAG inventory so far that can be used as a reference for studying milk lipids.

Current Knowledge on Interspecific Hybrid Palm Oils as Food and Food Ingredient

The consumers' opinion concerning conventional palm (Elaeis guineensis) oil is negatively affected by environmental and nutritional issues. However, oils extracted from drupes of interspecific hybrids Elaeis oleifera × E. guineensis are getting more and more interest, due to their chemical and nutritional properties. Unsaturated fatty acids (oleic and linoleic) are the most abundant constituents (60%-80% of total fatty acids) of hybrid palm oil (HPO) and are mainly acylated in position sn-2 of the glycerol backbone. Carotenes and tocotrienols are the most interesting components of the unsaponifiable matter, even if their amount in crude oils varies greatly. The Codex Committee on Fats and Oils recently provided HPO the "dignity" of codified fat substance for human consumption and defined the physical and chemical parameters for genuine crude oils. However, only few researches have been conducted to date on the functional and technological properties of HPO, thus limiting its utilization in food industry. Recent studies on the nutritional effects of HPO softened the initial enthusiasm about the "tropical equivalent of olive oil", suggesting that the overconsumption of HPO in the most-consumed processed foods should be carefully monitored.

Effect of Breed on Fatty Acid Composition of Meat and Subcutaneous Adipose Tissue of Light Lambs

Simple Summary

The recognition of the role of food in the improvement and preservation of health is receiving more and more attention among consumers, especially in developed countries. Fats from red meats are considered quite unhealthy because of their high levels of cholesterol and saturated fatty acids. Healthier lipid profiles of red meats can be achieved by a proper feed composition of animals, but other factors, such as breed, sex, and live weight, are able to affect the nutritional properties of meats. This investigation aimed to evaluate the effect of breed (Bergamasca, Italian Merino, and Sopravissana) on the fatty acid composition of invisible (intramuscular) and visible (subcutaneous) fats of light lambs reared in Central Italy transhumant farms. They recently gained a Protected Geographical Indication label (European Union, Commission Implementing Regulation No. 475/2013), as ”Agnello del Centro Italia”. It is an income opportunity for local farms that passes through the nutritional valorization of lamb meat. The indices of nutritional quality of fats have showed that the meat of Italian Merino and Sopravissana lambs had better nutritional quality than the Bergamasca breed.

Abstract

Lamb meat is the main product of Central Italy transhumant farms, where lambs are traditionally reared with their mothers on pastures and are supplemented with concentrates and/or hay from day 20–30 until slaughter. However, few data are available on the fatty acid (FA) composition of unweaned lambs reared by extensive systems in Central Italy. The study aimed to evaluate the effect of breed (Bergamasca, Italian Merino, and Sopravissana) on the FA composition of intramuscular (longissimus lumborum, LL) and subcutaneous (SC) fats of light lambs. Statistical analysis showed that breed had effect only on some FAs in LL muscle fat (C18:0, C20:0, C14:1, C16:1, C17:1, C18:3 n-3, trans and conjugated linoleic acid isomers) and in SC adipose tissue (C21:0, C16:1, C18:1, C20:4 n-6, C20:5 n-3, C18:1 trans isomers). Gas chromatography data in combination with a chemometric approach could have some potential to discriminate among breeds. Indices of nutritional quality of the lipids suggested that the meat of Italian Merino and Sopravissana lambs might have better nutritional quality than Bergamasca; further studies, involving a greater number of animals, are needed to confirm these early results.

Addition of Olive Pomace to Feeding Substrate Affects Growth Performance and Nutritional Value of Mealworm (Tenebrio Molitor L.) Larvae

The well-recognized efficiency of Tenebrio molitor larvae to convert low quality organic matter into a nutritionally valuable biomass was exploited to manage solid wastes coming from the olive oil industry, which represent a severe environmental challenge in the Mediterranean area. Three organic pomace-enriched substrates (mixtures middlings/pomace 3:1, 1:1, and 1:3) were assessed, together with 100% organic wheat flour and 100% organic middlings as control feeds. A feeding substrate made up of 25% olive pomace and 75% wheat middlings appeared to be the best compromise between growth performance (larval and pupal weights, survival rate, development time) and nutritional properties of mealworm larvae. In fact, larvae fed the 3:1 feed showed the highest dry matter (DM) yield (38.05%), protein content (47.58% DM), and essential/non-essential amino acids ratio (1.16). Fat content (32.14% DM) and fatty acid composition were not significantly different than those of larvae fed more pomace-enriched feeds.

Triacylglycerol Composition of Breast Milk during Different Lactation Stages

Triacylglycerol (TAG) composition of breast milk plays an important role in improving digestion, absorption, and metabolism when consumed by infants. This study characterized the TAG profile of human colostrum, transitional, and mature milk samples from 103 women. Significant differences in the TAGs composition of breast milk fat from three lactation stages were observed. The TAGs with high molecular weight and unsaturated fatty acid (such as 1,3-olein-2-palmitin (OPO) and 1(3)-olein-2-palmitin-3(1)-linolein (OPL)) were enriched in colostrum, while the TAGs containing medium-chain fatty acids were more abundant in transitional and mature milk than that in colostrum. Of note, OPL was the most common TAG in breast milk of Chinese women while the most common TAG in breast milk of Western women was OPO. This data will promote the development of infant formulas in terms of the TAG composition more suitable for infants.

Fatty acid positional distribution (sn-2 fatty acids) and phospholipid composition in Chinese breast milk from colostrum to mature stage

This study quantified the fatty acid profile with emphasis on the stereo-specifically numbered (sn) 2 positional distribution in TAG and the composition of main phospholipids at different lactation stages. Colostrum milk (n 70), transitional milk (n 96) and mature milk (n 82) were obtained longitudinally from healthy lactating women in Shanghai. During lactation, total fatty acid content increased, with SFA dominating in fatty acid profile. A high ratio of n-6:n-3 PUFA was observed as 11:1 over lactation due to the abundance of linoleic acid in Chinese human milk. As the main SFA, palmitic acid showed absolute sn-2 selectivity, while oleic acid, linoleic acid and α-linolenic acid, the main unsaturated fatty acids, were primarily esterified at the sn-1 and sn-3 positions. Nervonic acid and C22 PUFA including DHA were more enriched in colostrum with an sn-2 positional preference. A total of three dominant phospholipids (phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM)) were analysed in the collected samples, and each showed a decline in amount over lactation. PC was the dominant compound followed by SM and PE. With prolonged breast-feeding time, percentage of PE in total phospholipids remained constant, but PC decreased, and SM increased. Results from this study indicated a lipid profile different from Western reports and may aid the development of future infant formula more suitable for Chinese babies.

Triacylglycerol Analysis in Human Milk and Other Mammalian Species: Small-Scale Sample Preparation, Characterization, and Statistical Classification Using HPLC-ELSD Profiles

In this work, a method for the separation of triacylglycerols (TAGs) present in human milk and from other mammalian species by reversed-phase high-performance liquid chromatography using a core-shell particle packed column with UV and evaporative light-scattering detectors is described. Under optimal conditions, a mobile phase containing acetonitrile/n-pentanol at 10 °C gave an excellent resolution among more than 50 TAG peaks. A small-scale method for fat extraction in these milks (particularly of interest for human milk samples) using minimal amounts of sample and reagents was also developed. The proposed extraction protocol and the traditional method were compared, giving similar results, with respect to the total fat and relative TAG contents. Finally, a statistical study based on linear discriminant analysis on the TAG composition of different types of milks (human, cow, sheep, and goat) was carried out to differentiate the samples according to their mammalian origin.

Crude palm oil from interspecific hybrid Elaeis oleifera×Elaeis guineensis: fatty acid regiodistribution and molecular species of glycerides

The composition and structure of triacylglycerols (TAGs) and partial glycerides of crude palm oil obtained from interspecific hybrid Elaeis oleifera×Elaeis guineensis, grown in Colombia, were fully characterised and compared to data obtained by analysing crude African palm oil. Hybridisation appears to substantially modify the biosynthesis of fatty acids (FAs) rather than their assembly in TAGs. In fact, total FAs analysis showed significant differences between these two types of oil, with hybrid palm oil having a higher percentage of oleic acid (54.6 ± 1.0 vs 41.4 ± 0.3), together with a lower saturated fatty acid content (33.5 ± 0.5 vs 47.3 ± 0.1), while the percentage of essential fatty acid, linoleic acid, does not undergo significant changes. Furthermore, 34 TAG types were identified, with no qualitative differences between African and E. guineensis×E. oleifera hybrid palm oil samples. Short and medium chain FAs (8:0, 10:0, 12:0, 14:0) were utilised, together, to build a restricted number of TAG molecular species. Oil samples from the E. guineensis×E. oleifera hybrid showed higher contents of monosaturated TAGs (47.5-51.0% vs 36.7-37.1%) and triunsaturated TAGs (15.5-15.6% vs 5.2-5.4%). The sn-2 position of TAGs in hybrid palm oil was shown to be predominantly esterified with oleic acid (64.7-66.0 mol% vs 55.1-58.2 mol% in African palm oil) with only 10-15% of total palmitic acid and 6-20% of stearic acid acylated in the secondary position. The total amount of diacylglycerols (DAGs) was in agreement with the values of free acidity; DAG types found were in agreement with the representativeness of different TAG species.