Sn-2 Position Of Triacylglycerols Research Articles

Lipase-Catalyzed Synthesis of Structured Fatty Acids Enriched with Medium and Long-Chain n-3 Fatty Acids via Solvent-Free Transesterification of Skipjack Tuna Eyeball Oil and Commercial Butterfat.

Human milk lipids generally have the maximum long-chain fatty acids at the sn-2 position of the glycerol backbone. This positioning makes them more digestible than long-chain fatty acids located at the sn-1, 3 positions. These unique fatty acid distributions are not found elsewhere in nature. When lactation is insufficient, infant formula milk has been used as a substitute. However, the distribution of most fatty acids ininfant formula milk is still different from human milk. Therefore, structured lipids were produced by the redistribution of medium-chain fatty acids from commercial butterfat (CBF) and n-3 and n-6 long-chain fatty acids from skipjack tuna eyeball oil (STEO). Redistribution was carried out via transesterification facilitated by Asian seabass liver lipase (ASL-L). Under the optimum conditions including a CBF/STEO ratio (3:1), transesterification time (60 h), and ASL-L unit (250 U), the newly formed modified-STEO (M-STEO) contained 93.56% triacylglycerol (TAG), 0.31% diacylglycerol (DAG), and 0.02% monoacylglycerol (MAG). The incorporated medium-chain fatty acids accounted for 18.2% of M-STEO, whereas ASL-L could incorporate 40% of n-3 fatty acids and 25-30% palmitic acid in M-STEO. The 1H NMRA and 13CNMR results revealed that the major saturated fatty acid (palmitic acid) and unsaturated fatty acids (DHA and EPA) were distributed at the sn-2 position of the TAGs in M-STEO. Thus, M-STEO enriched with medium-chain fatty acids and n-3 fatty acids positioned at the sn-2 position of TAGs can be a potential substitute for human milk fatty acids in infant formula milk (IFM).

Use of natural biotechnological processes to modify the nutritional properties of bean-based and lentil-based beverages

The market for plant-based beverages (PBBs) is relatively new; hence, to enable its further development, it is important to use new raw materials and improve production technology. The use of natural biotechnological processes can diversify the segment of PBBs, which may offer products with better functionality than those available in the market. Therefore, the present study aimed to determine the effects of fermentation and germination on the nutritional properties of bean-based beverages (BBs) and lentil-based beverages (LBs). The applied processes significantly (p ≤ 0.05) influenced the characteristics of PBBs. Fermentation improved the antioxidant properties (e.g., by increasing the level of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity by 2–6% and 3–7% for BBs and LBs, respectively) and modified the fatty acid (FA) profile of PBBs. This process increased the share of polyunsaturated FAs in the sn2 position in triacylglycerols, which may promote its absorption in the intestine. The simultaneous use of germination and fermentation was most effective in decreasing oligosaccharide content (< 1.55 mg/kg), which may reduce digestive discomfort after consuming PBBs. We recommend that the designing of innovative legume-based beverages should include the application of fermentation and germination to obtain products with probiotic bacteria and improved nutritional properties.

Ultrasound-assisted extraction of cranberry seed oil: food waste valorization approach

Cranberry pomace considered as a by-product of fruit industry contains seeds which may be processed to highly nutritive oil. Conventional extraction methods may be, however, harmful to natural environment, thus alternative, ultrasound-assisted extraction method may be useful tool to reduce environmental impact. In the following study, sonication was applied to extract oil from cranberry seeds. The aim of the study was to determine the most efficient conditions of ultrasound-assisted extraction of oil and to investigate sonication influence on the properties of final product. Ultrasound amplitude and extraction time were independent variables; yield and maximum induction time of oils were responses. The most efficient conditions were amplitude of 95% and extraction time of 11.38 min. Model predicted extraction yield of 22.55 ± 0.36% (vs. actual 21.98 ± 0.08%) and induction time of 52.60 ± 0.95 min (vs. actual 61.95 ± 3.06 min). Detailed analyses of oil extracted in the most efficient conditions and the control sample were performed. Kinetic parameters of oil oxidation, fatty acid profile and distribution, melting characteristics studies were carried out. Sonication influenced activation energy of oxidation reaction, contribution of chosen fatty acids (oleic, α-linolenic and eicosenoic fatty acids) and distribution of oleic and α-linolenic fatty acids in sn-2 position of triacylglycerols. Slight changes in melting profile of oils were also recorded. Scanning electron microscopy of cranberry seeds revealed that ultrasound treatment resulted in pore enlargement and fat agglomeration damage. Additional studies of thermal properties of cranberry seeds: differential scanning calorimetry and modulated differential scanning calorimetry were performed, which confirmed that cranberry seeds may be a new source of oil with unique properties.

Palmitic Acid is Absorbed as sn-2 Monopalmitin from Milk and Formula with Rearranged Triacylglycerols and Results in Increased Plasma Triglyceride sn-2 and Cholesteryl Ester Palmitate in Piglets

Milk fatty acids contain 20–30% palmitic acid (16:0), with -70% of the 16:0 esterified to the sn-2 position of the milk triacylglycerol. Formulae containing vegetable and oleo oils contain different amounts of 16:0, but all have unsaturated fatty acids esterified to the triacylglycerol sn-2 position. Intraluminal triacylglycerol hydrolysis by endogenous lipases produces sn-2 monoacylglycerols and free fatty acids, which are absorbed and re-esterified in the enterocyte for secretion to plasma. The extent of absorption and re-esterification of sn-2 monoacylglycerols from milk or formula fats in infants is unknown. This was studied by feeding piglets sow milk or formulae containing similar total saturated fat, 18:1, 18:2(n-6) and 18:3(n-3) with unsaturated fatty acids at the sn-2 position or with rearranged triacylglycerols containing -30% 16:0, with 70% 16:0 in fatty acids at the sn-2 position. Feeding milk or 16:0 on the sn-2 position of formula with rearranged triacylglycerols resulted in higher 16:0 esterified to the plasma triacylglycerol sn-2 position and in cholesteryl esters than feeding formulae with 0.4 to 4.4% 16:0 in the sn-2 position fatty acids. The absorption of 16:0 as monopalmitin from milk and any metabolic importance in human infants has yet to be determined.

Fatty acids and minor functional compounds of hemp (Cannabis sativa L.) seeds and other Cannabaceae species

Nowadays, hemp (Cannabis sativa) seeds are receiving increased attention because of their high nutritional value. Among other nutrients, they contain a PUFA- and bioactive compounds-rich oil. Accordingly, this work was focused to establish the fatty acids (FA) content, the regiospecificity of triacylglycerols, and to quantify several bioactive compounds of relevant hemp seeds varieties and related taxa. Eight varieties of unhusked hemp seeds and eight samples of commercial husked hemp seeds were studied, and other Cannabaceae seeds: those from hop (Humulus lupulus) and European hackberry (Celtis australis). We found that all hemp seeds varieties constitute a rich source of essential PUFA as linoleic and α-linolenic acids, as well as oleic acid. PUFA were mostly distributed at the sn-2 position of triacylglycerols, thus, being highly bioaccessible, while SFA were mostly located at the sn-1,3 positions. The n–6/n–3 PUFA ratio was found to be nutritionally advantageous. Vitamin E compounds were noticeable, and γ-tocopherol was the major tocol found. Regarding phytosterols, campesterol and β-sitosterol were the most prominent compounds, while squalene content was also noticeable. Overall, the lipid fraction of hemp seeds can be considered as a source of essential and bioactive FA as well as an antioxidant- and cholesterol-lowering bioactive compounds-containing functional food.

Comprehensive evaluation of lipidomics profiles in golden threadfin bream (Nemipterus virgatus) and its by-products using UHPLC-Q-exactive Orbitrap-MS

Golden threadfin bream (Nemipterus virgatus) has become the second-largest surimi processing resource, but little is known about its lipidomics profiles. A comprehensive lipidomics analysis of golden threadfin bream and its by-products was performed. The results showed that golden threadfin bream contained high levels of phospholipid (4.54%–13.13% of total lipids), saccharolipid (5.22%–18.68%), docosahexaenoic acid (DHA, 11.07–21.54% of total fatty acids), eicosapentaenoic acid (EPA, 3.89–5.29%) and arachidonic acid (ARA, 2.36–3.64%). DHA tended to concentrate more on phospholipid than triacylglycerol and other lipid classes. Interestingly, DHA was mainly bonded to the sn-2 position of triacylglycerol and sn-1 position of phospholipid. Additionally, 1400 lipid molecular species belonging to 28 subclasses were identified by ultrahigh-performance liquid chromatography equipped with quadrupole-exactive orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS), and glycerolipid was the dominant lipid class. Glycerophospholipid and sphingolipid in fish head and viscera were relatively higher than muscle and skin. Furthermore, the chemometric models were used to differentiate and evaluate the four tissues, and 57 potential lipid biomarkers were screened. Hence, this study will contribute to comprehensively assess the nutritional value of golden threadfin bream and facilitate the high-value utilization of its by-products.

Comprehensive lipid profiles of sea cage aquaculture cobia (Rachycentron canadum) based on lipidomics

Cobia (Rachycentron canadum) is a significant fish species for mariculture with high nutritional value. This research aims to comprehensively investigate the lipid profiles of cobia tissues, including fatty acid profiles, characteristics of phospholipids (PL) and triacylglycerols (TAG), and lipid molecular species. The results showed that cobia contained high levels of total lipids (2.89 −32.09 % of wet weight), docosahexaenoic acid (DHA, 10.83 −14.69 % of total fatty acids) and eicosapentaenoic acid (EPA, 3.54 −9.68 %). Compared with TAG, higher levels of polyunsaturated fatty acids, DHA/EPA in particular, were concentrated in PL. Interestingly, DHA was predominantly distributed in the sn-1 position of PL and the sn-2 position of TAG, whereas EPA was predominantly distributed in the external positions of PL and TAG. Additionally, at least 693 molecular species from 23 subclasses were identified by ultrahigh-performance liquid chromatography-quadrupole exactive-mass spectrometry (UPLC-Q-Exactive-MS). Glycerophospholipids (63.19 −66.61 %) and glycerolipids (19.17 −22.21%) were the major lipid classes in cobia tissues, and the majority of them contained DHA and EPA. Hence, this comprehensive analysis will help to evaluate the lipid nutritional values and facilitate exploitation in cobia consumption and processing.

Similarity Index for the Fat Fraction between Breast Milk and Infant Formulas.

The similarity of the fat fraction in infant formulas rich in either bovine milk fat (MF) or vegetable oil (VO) to breast milk was evaluated by analyzing their lipid composition. Milk fat-rich formulas were highly similar (average similarity index 0.68) to breast milk compared to the VO-rich formulas (average similarity index 0.56). The highest difference in the indices was found in the contents of cholesterol (0.66 vs 0.28 in MF- and VO-rich formulas, respectively, on average) and polar lipids (0.84 vs 0.53), the positional distribution of fatty acids in the sn-2 position of triacylglycerols (0.53 vs 0.28), and fatty acid composition (0.72 vs 0.54). The VO-based formulas were superior in similarity in n – 6 PUFA. Thus, the addition of bovine MF fractions is an effective way to increase the similarity between the lipid composition of infant formulas and human milk.

Plant and algal lysophosphatidic acid acyltransferases increase docosahexaenoic acid accumulation at the sn-2 position of triacylglycerol in transgenic Arabidopsis seed oil.

Although docosahexaenoic acid (DHA), an important dietary omega-3 polyunsaturated fatty acid (PUFA), is at present primarily sourced from marine fish, bioengineered crops producing DHA may offer a more sustainable and cost-effective source. DHA has been produced in transgenic oilseed crops, however, DHA in seed oil primarily occupies the sn-1/3 positions of triacylglycerol (TAG) with relatively low amounts of DHA in the sn-2 position. To increase the amount of DHA in the sn-2 position of TAG and in seed oil, putative lysophosphatidic acid acyltransferases (LPAATs) were identified and characterized from the DHA-producing alga Schizochytrium sp. and from soybean (Glycine max). The affinity-purified proteins were confirmed to have LPAAT activity. Expression of the Schizochytrium or soybean LPAATs in DHA-producing Arabidopsis expressing the Schizochytrium PUFA synthase system significantly increased the total amount of DHA in seed oil. A novel sensitive band-selective heteronuclear single quantum coherence (HSQC) NMR method was developed to quantify DHA at the sn-2 position of glycerolipids. More than two-fold increases in sn-2 DHA were observed for Arabidopsis lines expressing Schizochytrium or soybean LPAATs, with one Schizochytrium LPAAT driving DHA accumulation in the sn-2 position to 61% of the total DHA. Furthermore, expression of a soybean LPAAT led to a redistribution of DHA-containing TAG species, with two new TAG species identified. Our results demonstrate that transgenic expression of Schizochytrium or soybean LPAATs can increase the proportion of DHA at the sn-2 position of TAG and the total amount of DHA in the seed oil of a DHA-accumulating oilseed plant. Additionally, the band-selective HSQC NMR method that we developed provides a sensitive and robust method for determining the regiochemistry of DHA in glycerolipids. These findings will benefit the advancement of sustainable sources of DHA via transgenic crops such as canola and soybean.

Docosahexaenoic Acid Is Naturally Concentrated at the sn-2 Position in Triacylglycerols of the Australian Thraustochytrid Aurantiochytrium sp. Strain TC 20.

The Labyrinthulomycetes or Labyrinthulea are a class of protists that produce a network of filaments that enable the cells to glide along and absorb nutrients. One of the main two Labyrinthulea groups is the thraustochytrids, which are becoming an increasingly recognised and commercially used alternate source of long-chain (LC, ≥C20) omega-3 containing oils. This study demonstrates, to our knowledge for the first time, the regiospecificity of the triacylglycerol (TAG) fraction derived from Australian thraustochytrid Aurantiochytrium sp. strain TC 20 obtained using 13C nuclear magnetic resonance spectroscopy (13C NMR) analysis. The DHA present in the TC 20 TAG fraction was determined to be concentrated in the sn-2 position, with TAG (16:0/22:6/16:0) identified as the main species present. The sn-2 preference is similar to that found in salmon and tuna oil, and differs to seal oil containing largely sn-1,3 LC-PUFA. A higher concentration of sn-2 DHA occurred in the thraustochytrid TC 20 oil compared to that of tuna oil.

Impact of an Infant Formula Containing a Novel Fat Blend (Cow’s Milk Fat, Fish and Vegetable Oil) and Prebiotics on Stool Fatty Acid Soaps and Erythrocyte Fatty Acid Profiles in Full-Term Healthy Newborns

Introduction: Recently, new commercial infant formulas have been composed considering novel fat blends and oligosaccharides to better resemble the fatty acid (FA) composition and stereospecific distribution (e.g., increased amount of ß-palmitate) as well as probiotics content of human breast milk. We hypothesized that these newly composed infant formulas may decrease fecal FA soap excretion and may positively affect erythrocyte FA profiles compared with regular formulas. Methods: Healthy infants were randomly assigned to receive a high-sn-2-palmitate formula (>25% of the PA is esterified to the sn-2 position of the glycerol backbone, verum: n = 30) or a “standard” formula containing <10% of PA in sn-2 position and no oligosaccharides (control: n = 27); a non-randomized group of breast-fed infants served as control. Anthropometric data of the infants (body weight, recumbent length, and head circumference) were recorded at inclusion (visit 1) and 6 and 12 weeks after onset of intervention (visits 2 and 3). Blood samples for erythrocyte FA analysis (gas chromatography) were taken at visits 1 and 2; stool samples were collected at visit 2. Results: Quantitative formula intake (mL/kg body weight × day) at visit 2 (verum: 155 ± 30, control: 164 ± 30) and visit 3 (verum: 134 ± 26, control: 134 ± 21) was comparable. Six weeks after onset of intervention, stool total FA soaps, palmitate soaps, and total FAs were similar in both formula-fed groups but significantly higher than in breast-fed infants. During the 6-week intervention, erythrocyte palmitate decreased significantly from baseline in all 3 groups with no group differences (verum: 29.20 ± 1.17 to 27.12 ± 0.66, control: 29.88 ± 2.00 to 27.01 ± 0.94, breast-fed: 30.20 ± 0.86 to 26.84 ± 0.98). For selected FAs, significant changes over time in verum and control group were obvious but without formula effects. Some variations in the FA profile of breast-fed infants compared to both verum and control groups were observed. Conclusions: In contrast to our hypothesis, feeding a newly composed infant formula based on a fat blend with 25% of PA in the sn-2 position of triacylglycerols and supplemented with a prebiotic could not decrease insoluble FA soap excretion compared with a standard product; in this respect, breastfeeding is obviously the best choice. Surprisingly, erythrocyte FA profiles were comparable in formula-fed and breast-fed infants; obvious alterations in FA composition of the respective fat sources and structure did not affect FA incorporation into membranes. Caution should be, however, exercised in drawing robust conclusions in the absence of larger, adequately powered intervention studies.

Co-expressing Eranthis hyemalis lysophosphatidic acid acyltransferase 2 and elongase improves two very long chain polyunsaturated fatty acid production in Brassica carinata

Docosadienoic acid (DDA, 22:2–13,16) and docosatrienoic acid (DTA, 22:3–13,16,19) are two very long chain polyunsaturated fatty acids (VLCPUFAs) that are recently shown to possess strong anti-inflammatory and antitumor properties. An ELO type elongase (EhELO1) from wild plant Eranthis hyemalis can synthesize the two fatty acids by sequential elongation of linoleic acid and alpha-linolenic acid, respectively. Seed-specific expression of this gene in oilseed crop Brassica carinata produced a considerable amount of DDA and DTA in transgenic seeds. However, these fatty acids were excluded from the sn-2 position of triacylglycerols (TAGs). To improve the production level and nutrition value of the VLCPUFAs in the transgenic oilseed crop, a cytoplasmic lysophosphatidic acid acyltransferase (EhLPAAT2) for the incorporation of the two fatty acids into the sn-2 position of triacylglycerols was identified from E. hyemalis. RT-PCR analysis showed that it was preferentially expressed in developing seeds where EhELO1 was exclusively expressed in E. hyemalis. Seed specific expression of EhLPAAT2 along with EhELO1 in B. carinata resulted in the effective incorporation of DDA and DTA at the sn-2 position of TAGs, thereby increasing the total amount of DDA and DTA in transgenic seeds. To our knowledge, this is the first plant LPAAT that can incorporate VLCPUFAs into TAGs. Improved production of DDA and DTA in the oilseed crop using EhLPAAT2 and EhELO1 provides a real commercial opportunity for high value agriculture products for nutraceutical uses.

Integral Stereoselectivity of Lipase Based on the Chromatographic Resolution of Enantiomeric/Regioisomeric Diacylglycerols.

Stereoselectivity, a distinctive characteristic of lipase (EC 3.1.1.3), refers to the ability to differentiate between enantiomeric positions (sn-1 and sn-3) in triacylglycerol (TAG). This property has been determined based on the time course of enantiomeric excess of diacylglycerol (DAG) considering several consecutive steps of lipase-catalyzed hydrolysis of TAG; however, this concept is insufficient to represent the true nature of lipases which are capable of hydrolyzing the sn-2 position of TAG under the condition acyl migration occurs. Here, we suggest "integral stereoselectivity" to capture the preference of lipases for all ester groups of both TAG and DAG, as a novel index of the stereochemistry of lipase. To determine integral stereoselectivity, we established an analytical system based on the chromatographic resolution of dioleoylglycerol (DO) enantiomers and regioisomers. DO enantiomers were derivatized with 4-nitrophenyl isocyanate, and subsequently, resolved by chiral-phase high-performance liquid chromatography-ultraviolet. Regioisomers of monooleoylglycerol and DO were analyzed by HPLC with an evaporative light-scattering detector. Time-course analysis of three model lipases involved in the hydrolysis of trioleoylglycerol validated the analytical system designed to determine the integral stereoselectivity. As an accurate indicator of lipase stereochemistry reflecting all hydrolysis steps, integral stereoselectivity can expedite the development of lipases with unique stereochemistry from agricultural sources and their application to the food industry.

The Enzymatic Preparation of Human Milk Fat Substitute Intermediate Rich in Palmitic Acid at sn-2 Position and Low-Unsaturated Fatty Acids at sn-1(3) Positions from Palm Oil Substrate.

The lipid products that consist of structured lipids rich in palmitic acid (16:0) at the sn-2 position of triacylglycerol (TAG) and rich in low-unsaturated fatty acids (FAs) (LUFAs), such as oleic acid; 18:1 and linoleic acid; 18:2 at the sn-1(3) positions, are useful intermediates for manufacturing human milk fat substitute (HMFS), which contains functional lipid components. In this study, the HMFS intermediate (HMFS-IM) was enzymatically prepared from palm oil without using other oil sources. First, the amount of 16:0 at the sn-2 position of TAG substrate was enhanced from 18.9% to more 34.5% via a random esterification reaction using a non-stereospecific lipase, Novozym® 435, to produce a random-palm substrate. Consequently, 2-monoacylglycerol (2-MAG) rich in 16:0 at the sn-2 position over 88%, together with the FA ethyl ester substrates rich in LUFAs, such as 18:1-Et and 18:2-Et above 93.5% was prepared through ethanolysis reaction using the same lipase from the random-palm substrate and by purification with urea complexation, respectively. As the preferred modified method, a continuous use of the same lipase to these reactions were achieved while reducing the usage of enzyme to half. Finally, an HMFS-IM rich in 16:0 at the sn-2 position more than 60% and LUFA at sn-1(3) positions was prepared using these palm oil-based products, including random-palm, palm-Et, and 2-MAG, via the interesterification reaction using a 1,3-stereospecific lipase, Lipozyme® RM-IM. Thus, HMFS-IM was successfully prepared by palm oil materials with a 65 wt% usage ratio. The concept described in this study will be useful for HMFS manufacturing from a single natural oil substrate, which is not initially rich in 16:0 at the sn-2 position.

Effect of milk fat-based infant formulae on stool fatty acid soaps and calcium excretion in healthy term infants: two double-blind randomised cross-over trials

BackgroundPalmitic acid (PA) is predominantly esterified at the SN-2 position of triacylglycerols in human milk. PA at the SN-2 position is more efficiently absorbed and results in reduced formation of PA soaps, as well as reduced fatty acid (FA) and calcium malabsorption. Bovine milk fat (MF), a natural source of SN-2-palmitate, was used in the fat blend of infant formulae (IF) in the current study to investigate its effect on stool fatty acid soaps, calcium excretion and stool characteristics.MethodsTwo double-blind, randomised cross-over trials (CS1, CS2) were conducted in parallel with healthy term, formula-fed infants aged 9–14 weeks. After a two-week run-in period, infants in CS1 (n = 17) were randomly allocated to receive either a 50% MF-based formula (50MF) or a 100% vegetable fat (VF) formula; in CS2 (n = 18), infants received either a 20% MF-based formula (20MF) or the VF formula, in a 2 × 2-week cross-over design. At the end of each two-week intervention period, stool samples were collected for FA, FA soaps and calcium excretion analysis and stool consistency was assessed according to the Amsterdam Infant Stool Scale (AISS).ResultsMF-based groups showed no significant difference in PA in stools compared to VF group, although reduced stool PA soaps (CS1: 111.28 ± 18.33 vs. 220.25 ± 29.35 mg/g dry weight, p < 0.0001; CS2: 216.24 ± 25.16 vs. 233.94 ± 35.12 mg/g dry weight, p = 0.0023), total FA soaps and calcium excretion (CS1: 46.40 ± 5.27 vs. 49.88 ± 4.77 mg/g dry weight, p = 0.0041; CS2: 46.20 ± 4.26 vs. 50.47 ± 6.71 mg/g dry weight, p = 0.0067) were observed. Furthermore, the 50MF group showed a favourable lower mean stool consistency score compared to the VF group (1.64 ± 0.49 vs. 2.03 ± 0.19, p = 0.0008).ConclusionsWhile the use of bovine MF in IF did not affect PA concentrations in stool, lower excretion of palmitate soaps, total FA soaps and calcium was seen in healthy term infants. 50MF formula also showed improved stool consistency. The use of MF in IF could be an interesting approach to improve gut comfort and stool characteristics in infants, warranting further research.Trial registrationNetherlands Trial Registry Identifier: NTR6702. Date registered: December 01, 2017.

Lipid profiles of Chinese soft-shell turtle eggs (Pelodiscus sinensis)

Studies have shown potential beneficial functions of turtle eggs, but the mechanism is not clear. The species and content of lipids have a significant impact on human health. The major lipid classes and fatty acids composition of dried Chinese soft-shell turtle eggs were characterized with the aim of clarifying the potential beneficial functions of turtle eggs from the perspective of lipid nutrition. 100 g dried turtle eggs power contained an average of 24.7 g of triacylglycerol (TAG), 1.24 g of phospholipid (PL) and 0.72 g of cholesterol. The striking feature of the lipid composition was the abundant n-3 polyunsaturated fatty acids, resulting in an excellent n-6/n-3 ratio (1.27) and low atherogenic index (AI) and thrombogenic index (TI) values, which were considered to be a healthier option for the human diet. A total of 85 TAG molecular species and 95 PL molecular species were obtained by lipidomics. ΣcisC18:1, C18:2n-6 and C18:3n-3 were preferentially esterified at sn-2 position of TAG. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) accounted for more than 90 % of the PL, while no sphingomyelin (SM) was detected. C22:6n-3 and C20:5n-3 were preferentially bound to PE and lysophosphatidylcholine (LPC) respectively.

Chemical composition, nutritive value and health benefits of edible clam Meretrix casta (Chemnitz) from West Coast of India.

The present study was undertaken with a view to determine the nutraceutical value of the commonly consumed edible clam, Meretrix casta (Chemnitz), based on the identification of its organic chemical constituents particularly lipids and carbohydrates. Electrospray ionization tandem mass analysis of the bivalve indicated maltodextrins to be the major carbohydrate constituent. Triacylglycerols (TAGs) (0.88%, dry weight) were rich in C14:0, C16:0 to C18:0 (6-11%) saturated and monounsaturated palmitoleic (C16:1n9c; 11.76%) and oleic fatty acids (C18:1n9c; 14.53%). Though the clams contained PUFAs which are known to be beneficial in lowering the risk of cardiovascular diseases, they were devoid of docosahexaenoic acid (C22:6n3). Maltodextrins being less digestible than glucose beneficially affects the host by selectively stimulating the growth of gut microflora particularly Lactobacillus and Bifidobacteria. These microflora inhibit colonization of pathogens by producing butyrate. The profile of sterols (1.67%, dry wt.) showed it to be a complex mixture of C26, C27, C29 and C30. To our knowledge no reports are available in the literature on the identification of maltodextrins and of positional distribution of PUFA's at the sn2 position of TAGs in M. casta. The results of this study demonstrated the positive attributes of the bivalve for human consumption.

Enzymatic Preparation and Oxidative Stability of Human Milk Fat Substitute Containing Polyunsaturated Fatty Acid Located at sn-2 Position.

The development of human milk fat substitutes (HMFSs), rich in palmitic acid (16:0) at the sn-2 position of triacylglycerol (TAG) and rich in unsaturated fatty acids (FAs) (oleic acid, 18:1 and linoleic acid, 18:2) at the sn-1(3) positions, has gained popularity. In this study, HMFSs containing polyunsaturated fatty acids (PUFAs) predominantly at the sn-2 position were prepared, and their oxidation stabilities were compared. First, a non-PUFA-containing HMFS (NP-HMFS) was produced by enzymatic reactions using Novozyme® 435 and Lipozyme® RM-IM as the enzymes and lard as the raw material. Second, HMFSs, containing 10 % PUFA at the sn-2 or sn-1(3) position, were individually prepared by enzymatic reactions using lard and fish oil as raw materials. Here, sn-2-PUFA-monoacylglycerol (MAG) was extracted from the reaction solution using a mixture of hexane and ethanol/water (70:30, v/v) to produce high-purity sn-2-PUFA-MAG with 78.1 % yield. For the PUFA-containing HMFS substrates, comparable oxidation stability was confirmed by an auto-oxidation test. Finally, HMFSs containing 10 % or 2 % sn-1,3-18:1-sn-2-PUFA-TAG species were prepared by enzymatic reactions and subsequent physical blending. The oxidative stability of sn-1,3-18:1-sn-2-PUFA-HMFS was two-fold higher than that of 1/2/3-PUFA-HMFS in which each PUFA was located without stereospecific limitations in TAG. The removal of PUFA-TAG molecular species with higher concentrations of unsaturated units had a significant effect. In addition, the oxidation stability increased with the addition of tocopherol as an antioxidant. Thus, the combined use of two strategies, that is, the removal of PUFA-TAG molecular species with high concentrations of unsaturated units and the addition of antioxidants, would provide a PUFA-containing HMFS substrate with high oxidative stability.

Effect of a Diet Rich in Interesterified, Non-Interesterified and Trans Fats on Biochemical Parameters and Oxidative Status of Balb-c Mice

The aim of this study was to investigate the effects of different modified fats on the body weight, biochemical profile, and biomarkers of hepatic oxidative status in Balb-c mice. The animals were divided into four groups and fed for 75 days with a normolipidic (Control Group, CG) or hiperlipidic diets (40% kcal) containing a commercial interesterified fat (IFG) rich in palmitic acid (39%); a blend of non-interesterified fat (NIFG), with 2-fold less saturated fatty acids at the sn-2 position of triacylglycerols; or a partially hydrogenated vegetable oil (PHFG), source of trans fatty acid (20%) and of linolenic acid (6%). The mice of the IFG and NIFG presented similar results in all evaluated parameters. The serum biochemical profile and hepatic oxidative stress markers in mice of the PHFG were similar to CG, except for total cholesterol (TC) which was significantly higher (p e PHFG. The mice feed with interesterified fat (IFG) showed serum TC (p fed with partially hydrogenated vegetable oil (PHFG). The hydrogenated fat source of trans fatty acid (20%) had less important metabolic effects than fats containing amounts of palmitic acid (interesterified or non-interesterified). Our results suggest that the replacement of hydrogenated fats by interesterified fats may not be such a simple solution to reduce or eliminate trans fatty acids in foods.

Enzymatic synthesis of structured triacylglycerols rich in 1,3-dioleoyl-2-palmitoylglycerol and 1-oleoyl-2-palmitoyl-3-linoleoylglycerol in a solvent-free system

Structured triacylglycerols (TAGs), rich in 1,3-dioleoyl-2-palmitoylglycerol (OPO) and 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL), were prepared by enzymatic acidolysis of fractionated palm stearin with free fatty acids. The effects of enzyme type, substrate molar ratio, enzyme load, temperature, and reaction time on the yields of OPO and OPL, palmitic acid (PA) content at the sn-2 position of TAG, and the percentage of PA at the sn-2 position relative to total PA content were investigated. Under optimal reaction conditions (palm stearin/oleic acid/linoleic acid molar ratio of 1:8:4, lipase NS 40086 loading of 8%, 60 °C, 4 h), the combined yields of OPO and OPL was 69.26%, PA content at the sn-2 position reached 87.75%, and the relative percentage of PA at the sn-2 position was up to 71.07%. The synthesized TAGs have potential to be used in infant formulas.