Effect of processing and storage on neutral lipids of buffalo meat

Three muscles viz. Triceps brachii (TB), Longissimus dorsi (LD) and Biceps femoris (BF) from different anatomical locations of adult male buffaloes were stored after broiling and pressure cooking under refrigerated (4°C) condition for 3, 6, 9 days and 30, 60, 90 days under frozen (-10°C) storage. At the end of each storage interval they were analysed for total lipids, cholesterol contents and glyceride fractions i.e. monoglycerides (MG), diglycerides (DG), and triglycerides (TG). Muscles differed significantly in total lipids as well as contents of all glyceride fractions. Muscle LD had significantly higher total lipid content than TB and BF. Muscles differed significantly in their esterfied cholesterol (EC) contents. Heat processing increased total lipids, cholesterol, MG, DG and TG contents of all the buffalo muscles studied. Total cholesterol contents remained unchanged during refrigerated and frozen storage. However, EC, MG, DG and TG contents declined during storage. The influence of anatomical locations on fatty acid composition of neutral lipids was observed. The ratio of unsaturated to saturated fatty acids increased due to cooking. A gradual decrease in mono- and polyunsaturated fatty acids was recorded during refrigerated and frozen storage.     

EFFECT OF POSTMORTEM AGING ON CHICKEN MUSCLE LIPIDS

Neutral lipids of fresh chicken breast muscles are shown to be triglycerides, sterols and sterol esters with only traces of mono- and diglycerides and free fatty acids. Phospholipids include measurable quantities of phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl serine, sphingomyelin, diphosphatidyl glycerol, lysophosphatidyl choline and lysophosphatidyl ethanolamine. Fatty acid analyses of several of the lipid fractions are also included. Decreases in phosphatidyl choline and phosphatidyl ethanolamine coupled with increases in lysophosphatidyl choline, lysophosphatidyl ethanolamine and free fatty acids after 48 hr postmortem in the cold indicate phospholipase A activity concurrent with other postmortem changes. The significance of the results is discussed.     

Fumgal lipids. I. Effect of different nitrogen sources on the chemical composition

The effect of three nitrogen sources on the chemical composition of seven fungi, namely: Aspergillus niger, A. luchuensis, Penicillium crustosum, Alternaria tenuis, Rhizoctonia solani, Mucor sp. and Pythium irregulare has been studied. The various fungi showed a great variation with respect to lipid percentage and total lipid content. Lipid content varied from 3.2 to 41.5%. Non-polar lipids were comprised of monoglycerides, diglycerides, free sterols, free fatty acids and triglycerides. The quantitative make-up of the non-polar lipid varied with different nitrogen sources. Palmitic, stearic, oleic and linoleic acids were the major fatty acids while lauric, myristic, palmitoleic, linoleic and arachidic were the minor ones. The fatty acid composition was dramatically changed by changing the nitrogen source. Since different fungi responded differently to changes in nitrogen source, no generalisation could be made. Two-dimensional thin-layer chromatography of the polar lipid fraction of these fungi revealed the presence of a maximum of fifteen spots. Phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl inositol were the major spots while lysophosphatidyl choline, lysophosphatidyl ethanolamine and phosphatidyl glycerol were present in smaller quantities. In comparison to phospholipids, glycolipids (except sterol glycoside) were present in relatively lower concentration. Pythium irregulare was very characteristic in having no glycolipids at all.     

Isolation and characterization of whey phospholipids

A freeze-dried whey powder was produced by microfiltration of Cheddar cheese whey. A 0.2-micron ceramic membrane in a stainless steel housing unit was used to concentrate components > 400 kDa present in the whey. The experimental whey powder, derived from Cheddar cheese whey, and a commercial whey powder were subjected to proximate analysis, lipid classes, phospholipid classes, and fatty acid compositional analyses. Commercial whey powder and commercial soybean lecithin were subjected to an alcohol fractionation procedure in an effort to alter the ratio of phosphatidyl choline to phosphatidyl ethanolamine and the functionality of dairy phospholipids. The fractionation procedure produced an alcohol-insoluble fraction containing 84% phosphatidyl ethanolamine, whereas the alcohol-soluble fraction resulted in a decrease in the phosphatidyl choline to phosphatidyl ethanolamine ratio. The commercial whey contained a higher ratio of phospholipids to neutral lipids compared with the experimental whey. The classes of phospholipids present within the two wheys were similar, whereas the experimental whey contained a phosphatidyl choline content twice that of the commercial whey, and the phospholipids composition of both wheys differed from the milk fat globule membrane. Comparison of the phospholipids and fatty acid composition of the wheys with the soy lecithin revealed that although the wheys were similar to each other, they differed from the soy lecithin in both the classes of phospholipids present and in the fatty acid composition. These compositional differences may influence the functionality of whey phospholipids.     

Fatty acid and aldehyde composition of individual phospholipid classes of rabbit skeletal muscles is related to the metabolic type of the fibre

The fatty acid composition of individual phospholipid classes as related to metabolic type of fibre in the rabbit was studied. The fatty acid composition of the individual phospholipid classes of five muscles were compared: two glycolytic ones (Longissimus lumborum and Psoas major), two oxidative ones (Soleus and Semimembranosus propriosus,) and an intermediate one (Gastrocnemius laterale). It was shown that except for phosphatidyl inositol (PI), the fatty acid compositions of the main phospholipid classes were strongly related to the metabolic type of the fibres; phosphatidyl ethanolamine (PE) of oxidative muscles contains less 18:2 n-6 and more 18:0 and long chain PUFA of the n-6 and n-3 series than that of glycolytic ones; phosphatidyl choline (PC) of oxidative muscles contains more 18:0 and less 16:0 and 18:2 n-6 than that of glycolytic ones; cardiolipin of the oxidative muscles contains less 18:2 n-6 than those of the glycolytic ones. These differences in fatty acid composition of PE, PC and cardiolipin explain a large part of the differences in fatty acid compositions of the total phospholipids of glycolytic and oxidative muscles.     

Lipids of berseem (Trifolium alexandrinum) seed

Berseem seed oil was fractionated into non-polar and polar components. Tentative identification was made of hydrocarbons, sterol esters, triglycerides, free fatty acids and partial glycerides in the non-polar fraction and of lysophosphatidyl choline, phosphatidyl inositol, lysophosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl ethanolamine, digalactosyl diglycerides, sterol glycosides, phosphatidic acid, monogalactosyl diglycerides, cerebrosides and esterified sterol glycosides in the polar fraction. The fatty acid constituents of the major polar and of all the non-polar lipid components are also reported.     

Characterization of Shrimp Lipids

Edible shrimp (Penaeus aztecus) tissue contains approximately 1.2% extractable lipids, the majority of which are phospholipids. Data from the gravimetric quantitation of lipid classes isolated by column chromatography indicated that phosphatidyl choline was the predominant phospholipid and cholesterol the predominant neutral lipid in edible shrimp tissue. Fatty acid distribution data indicated that sphingomyelins contained the greatest percent by weight of unsaturated fatty acids while cholesterol esters contained the greatest proportion of saturated fatty acids. Enzymatic hydrolysis followed by gas liquid chromatography of phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine indicated that fatty acids located at the β position were more highly unsaturated than those at the α position.     

Identification and Quantitative Analysis of Phospholipids in Cocoa Beans

SUMMARY: The lipids extracted from several common cocoa bean varieties were separated into neutral lipid, glycolipid, and phospholipid fractions. The composition of the total lipid extract was 98% neutral lipid and 1 to 2% oolar lioid of which aporoximatelv 70% was glycolipid and 30% was phospholipids. Two-dimensional thin-layer chromatography was used to separate all of the known major phospholipids. The relative distribution of the phospholipids was determined by quantitative phosphorus analyses of individual spots scraped from two-dimensional thin-layer plates. The major components were lysophosphatidyl choline, phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl inositol. Phosphatidyl choline was found to contribute 36 to 40% of the phospholipids of cocoa beans. The phospholipid composition of Accra, Arriba, and Bahia beans was shown to be quite similar although minor variations were observed.     

Changes in milk fat phospholipids during lactation

Changes in lipid composition were studied in milk obtained on postpartum d 3 (colostrum), 7, 42, and 180 from 12 Holstein cows. Triglycerides, 96 to 97% of total lipids, were relatively constant during lactation. Phospholipids and cholesterol declined with advancing lactation. Concentrations of the fatty acids synthesized within the mammary gland, C10:0 to C16:0, increased about 50% from 7 to 42 d of lactation. During this period, compensatory decreases were observed in C18:1. The phospholipids were separated into five major classes: sphingomyelin, phosphatidyl choline, serine, inositol, and ethanolamine for fatty acid analysis. The changes that occurred in milk total fatty acids were reflected in phosphatidyl phospholipid fatty acid composition: an increase in medium-chain fatty acids and a decrease in polyunsaturated fatty acids of 18, 20, and 22 carbon atom chain length as lactation progressed. These changes are consistent with the theory that milk phospholipids are synthesized de novo entirely in the mammary gland.     

Relative Role of Individual Phospholipids on Thiobarbituric Acid Reactive Substances Formation in Chicken Meat, Skin and Swine Aorta

Fatty acid profiles and distribution of individual phospholipids (PL) in the total PL were determined in chicken meat and skin and swine aortas, and the contribution of each PL to malondialdehyde (MDA) formation was studied. Results indicate that phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) produced 70-77% of the total PL MDA while 16-25% of the MDA was formed by phosphatidyl inositol (PI) and phosphatidyl serine (PS). Much lower concentrations of MDA (3-6%) were formed by sphingomyelin (SP), cardiolipin (CL) and lysophosphatidyl choline (LyPC). In all analyzed tissues, both the MDA concentration and the percentage of polyenoic fatty acids, especially arachidonic acid, were highest in PI followed by PE, PS, PC, CL LyPC, and SP.     

Effect of cooking and storage on lipid oxidation and development of cholesterol oxidation products in water buffalo meat

Buffalo meat was subjected to two cooking methods viz. broiling and pressure cooking and two storage procedures viz. refrigerated (4 °C) storage for six days and frozen (-10 °C) storage for 90 days. Changes in lipid oxidation and development of cholesterol oxidation products were studied in raw as well as cooked meat samples. Total lipid, phospholipid, cholesterol, free fatty acid, glycolipid and glyceride contents increased significantly on cooking of meat but did not show any significant changes during either refrigerated or frozen storage except for free fatty acid content which showed an increase. The TBA values also increased during storage but not to the extent of indicating rancidity. Cholesterol oxidation products separated by thin layer chromatography were: cholestanetriol, 7-α-hydroxycholesterol, 19-hydroxycholesterol, 7-ketocholesterol, cholesterol-α-epoxide, cholesterol-β-epoxide and an unidentified fraction. All these fractions, except for the unidentified fraction, increased on cooking and storage. The cholesterol-β-epoxide fraction was resistant to changes. Changes in broiled meat were more pronounced compared to pressure cooked meat. Frozen storage did not prevent the development of cholesterol oxidation products in buffalo meat.     

The composition of the fatty acids and aldehydes of the ethanolamine and choline phospholipids of various meats

The ethanolamine phospholipids of beef, lamb, pork and chicken examined in this study contained over 40% of ethanolamine plasmalogen, whereas fish contained only 13%. The level of choline plasmalogen in choline phospholipids was less than 1% in fish and ranged from 10 to 30% in the other four meats. Palmitaldehyde was the major fatty aldehyde in the choline plasmalogens of beef, lamb, pork and chicken (65–80% of total aldehydes), but was present at lower levels in the ethanolamine plasmalogens. The per cent fatty acid compositions of phosphatidylethanolamine and the corresponding ethanolamine plasmalogen were very similar, being typically low in palmitic acid but very high (56–74%) in polyunsaturated fatty acids. The fatty acids of the choline plasmalogens contained more polyunsaturated fatty acids than the corresponding phosphatidyl cholines, but at lower levels than in the fatty acids of the ethanolamine phospholipids.     

Phospholipids of marine origin. IV. The abalone (Haliotis midae)

Phospholipids of the abalone were separated into component fractions by chromatography on silicic acid. The phospholipids were remarkable for the presence (6%) of an unusual sphingolipid liberating 2-amino-ethylphosphonic acid on hydrolysis, and for the high proportion of plasmalogens (23%). The presence of phosphatidyl ethanolamine plus ethanolamine plasmalogen (32%), phosphatidyl serine (5%), phosphatidyl inositol (5%), phosphatidyl choline (41%) and sphingomyelin (1%) were also demonstrated. The fatty acid distribhion in the phospholipids, the non-phosphorylated lipids and the unusual sphingolipid was determined by gas chromatography. In general these results show a similarity between the phospholipid and the non-phosphorylated lipid fatty acids, the former being richer in long chain polyunsaturated fatty acids. Fatty acids of the unusual sphingolipid were outstanding for the high palmitic (53%) and stearic acid (15%) content.     

Changes in the composition of the rumen and abomasum lipids of sheep from birth to maturity

The composition of the lipids of the rumen and abomasum tissues of foetal (at term), 1 month, 2 month and 1-2-year old sheep grazed on pasture has been determined. The lipid content of the rumen tissues increased from 2.0% at birth to 3.4% in 1-2-year old sheep While that of the abomasum tissues increased from 2.6 to 5.7%. The main change in the neutral lipid fraction was a decrease in the hydrocarbon content from 0.13 % in the rumen tissues and 0.08 % in the abomasum tissues at birth to 0.003% and 0.006% respectively in the 1-2-year old sheep. The main components of the phospholipid fraction of the rumen and abomasum tissues were 34.9- 46.8% phosphatidyl choline; 14.623.5 % phosphatidyl ethanolamine; 14.3-21.1 % sphingomyelin; with smaller amounts of lysophosphatidyl choline (4 13-12.6 %), acidic phospholipids (cardiolipin) (4.1-8 -5 %) and phosphatidyl inositol/phosphaticlyl serine (3.0-5.5 %). No marked changes in phos- pholipid composition with age were noted. The amounts of phosphatidyl choline and phosphatidyl ethanolamine tended to be higher in the abomasum than in the rumen whereas the sphingomyelin content of the rumen tissue phospholipids was generally greater than that of the abomasurn tissue phospholipids. From the fatty acid composition of the triglycerides of the rumen and abomasum tissues it appeared that the foetal triglycerides were largely, though not entirely, of endogenous origin. In contrast the phospholipids of the foetal rumen and abomasum tissues contained di- and poly-unsaturated as well as branched-chain fatty acids in proportions similar to those found in older animals having access to pasture. From these results it is suggested that the phospholipids of the foetus are derived to a considerable extent from the maternal phospholipids.     

Role of seed phosphatides as antioxidants for ghee (butter fat)

Antioxidant potentiality of seed phospholipids for stored ghee was found to be in the order of sunflower (Helianthus annuus L.), groundnut (Arachis hypogea), soybean (Glycine max) and cotton seed (Gossypium sp.), possibly corresponding to their phosphatidyl ethanolamine content. Out of phosphatidyl choline, phosphatidyl ethanolamine and phosphatidic acid, phosphatidyl ethanolamine was found to be the most effective antioxidant. Antioxidant property of phosphatidyl ethanolamine did not vary with the seed source, indicating that the fatty acid portion of the molecule played no role in protecting ghee against oxidation. In stored ghee addition of phosphatidyl ethanolamine and phosphatidyl choline reduced lipolysis, probably by interacting with the lipase system. During storage, phosphatidyl ethanolamine afforded better protection against the oxidation of unsaturated fatty acids.     

Composition of wheat-flour lipids

Lipids were extracted from a single sample of wheat flour using three solvent systems: ethanol–diethyl ether–water (2:2:1 by vol.); chloroform–methanol (2:1 by vol.); and water-saturated n-butanol. Analysis of the extracts and of residual lipid in the extracted flour showed that water-saturated n-butanol was the most efficient solvent. Wheat-flour lipids were extracted with water-saturated n-butanol and separated by chromatographic procedures into individual components. The lipid classes which were isolated and studied were steryl ester, free sterol, 6-O-acyl steryl glucoside, steryl glucoside, triglyceride, diglyceride, monoglyceride, free fatty acid, monogalactosyl diglyceride, 6-O-acyl monogalactosyl diglyceride, digalactosyl diglyceride, digalactosyl monoglyceride, monoglycosyl ceramide, diglycosyl ceramide, N-acyl phosphatidyl ethanolamine, N-acyl lysophosphatidyl ethanolamine, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, phosphatidyl choline, lysophosphatidyl choline, phosphatidyl serine and phosphatidyl inositol. Monogalactosyl monoglyceride was also tentatively identified. The quantitative distributions of the lipid classes were determined. Monoglycosyl ceramide contained small amounts of normal fatty acids (12:0–24:0) and large amounts of 2-hydroxy fatty acids (principally 16:0 and 20:0), with similar amounts of dihydroxy long-chain bases (18:0 and 18:1) and trihydroxy long-chain bases (18:0, 18:1, 19:0, 19:1, 20:0, 22:0). The principal sterols were identified as β-sitosterol, campesterol, and C₂₈ and C₂₉ saturated sterols. The fatty acids in the sterol lipids were principally 16:0 (50–60%) and 18:2 (28–30%) with small amounts of 16:1, 18:0, 18:1 and 18:3. The fatty acids in all the glycerides were principally 18:2 (51–84%) with lesser amounts of 16:0, 18:0, 18:1 and 18:3.     

LIPIDS OF CURED CENTENNIAL SWEET POTATOES

SUMMARY –Lipids isolated from cured Centennial sweet potatoes were identified and quantitated by a combination of column and thin layer chromatography. These lipids were shown to consist of 42.1% neutral lipids, 30.8% glycolipids and 27.1% phospholipids. Triglycerides and steryl esters were the major lipids of the neutral fraction. Among the phospholipids, phosphatidyl ethanolamine, phosphatidyl choline and phosphatidyl inositol were the most abundant. Galactolipids and the steryl glucosides were also present. The predominant fatty acids were stearic, palmitic, oleic, linoleic and linolenic.     

Influence of carcass weight on instrumental and sensory lamb meat quality in intensive production systems

The effects of cooking viz. pressure-cooking and broiling and storage at 4 °C for six days and -10 °C for 90 days on lipid oxidation and development of cholesterol oxidation products in mutton were studied. Results revealed that cooking of meat significantly increased the total lipids, phospholipids, cholesterol, glycolipids, free fatty acids and glycerides, but they did not change during refrigerated and frozen storage. The TBA values increased on cooking and during storage. However, the values were below the threshold level for rancidity development. The following cholesterol oxidation products were separated by thin layer chromatography cholestanetriol, 7-α-hydroxy cholesterol, 19-hydroxycholesterol, 7-ketocholesterol, cholesterol-α-epoxide, cholesterol-β-epoxide and an unidentified fraction. All these fractions except the unidentified fraction increased on cooking. On refrigerated and even on frozen storage all these fractions increased except the unidentified fraction, which showed a concomitant reduction. The changes in broiled meat were more pronounced compared to pressure-cooked meat. Results clearly indicated that even frozen storage of cooked meat did not prevent the development of cholesterol oxidation products.     

Lipolysis in muscles during refrigerated storage as related to the metabolic type of the fibres in the rabbit

The relation between lipolysis and the metabolic fibre type was investigated during refrigerated storage of rabbit muscles. Free fatty acid, monoacylglycerol and diacylglycerol contents and free fatty acid composition were compared in five muscles immediately after slaughter and after a 7-day-storage at 4°C. The results showed that. (1) The amount of free fatty acids sharply increased during the refrigerated storage (from 2-10 to 11-32 mg/100 g of muscle), especially that of long chain polyunsaturated fatty acids (from less than 0.1 to 1.4-3.3 mg/100 g of muscle). (2) The glycolytic muscles contained 1.5 times less free fatty acids than the oxidative ones. However, the rates of phospholipid and triacylglycerol hydrolysis were not related to the metabolic type of the fibres. (3) The contribution of phospholipids to free fatty acid fraction was twice that of triacylglycerols in the glycolytic muscles whereas it was similar or lower to that of triacylglycerols in the oxidative muscles.     

Lipolytic and oxidative changes in two Spanish pork loin products: dry-cured loin and pickled-cured loin

Lipolytic and oxidative changes were studied in two typical meat products from pork loin, dry-cured loin (DCL) and pickled-cured loin (PCL). Neither product registered changes in the percentages of the main lipid fractions: non polar lipids, phospholipids and cholesterol. However, in dry cured loin an important decrease was recorded in the main phospholipid classes, phosphatidyl choline and phosphatidyl ethanolamine. Muscle lipolytic enzymes were active in both products, and were accompanied by a significant increase in free fatty acids, from 0.580% (of total lipid) in fresh loin to 5.65 in DCL and 2.95% in PCL. With respect to oxidative changes, the peroxide value decreased in both products, and the TBA number only increased in PCL.