Effects of drying process on biochemical and microbiological quality of silverside (fish) Atherina lagunae

Changes in biochemical and microbiological quality of silverside during two drying process were investigated. Total fatty acid and amino acid contents in silverside were 5.42 and 10.9 g 100 g^?1 fresh sample, respectively, in which, palmitic acid and glutamic acid were the most abundant. N‐3 and n‐6 polyunsaturated fatty acids (PUFA) levels were 0.59 and 0.62 g 100 g^?1 fresh silverside respectively. After hot air and solar drying treatments, Peroxide value and thiobarbituric acid reactive substances of the total lipids increased significantly (P < 0.05) to reach 2.58 and 3.41 meq active O₂ kg^?1 oil and 0.87 and 1.27 mg MA kg^?1 oil, respectively. Fatty acid profile of non‐polar lipid remains unchanged during experimental drying process. However, PUFA (% of total fatty acids) of polar lipid decreased significantly (P < 0.05) during both drying process with lower levels in solar drying process. Drying conditions had a significant effect on the microbiological quality. Therefore, mesophiles and total coliforms increased within drying treatment with higher counts in solar drying process.     

Nutritional composition and sensory attributes of Alaskan flatfishes compared to plaice (Pleuronectes platessa)

Proximate composition, fatty acids profiles and other nutritional values were evaluated for fillets of Limanda aspera (yellowfin sole), Lepidopsetta bilineata (southern rock sole) and Lepidopsetta polyxystra (northern rock sole) and compared to North Sea plaice (Pleuronectes platessa). Additional information is given on the composition of fillets from arrowtooth flounder (Atheresthes stomias). Plaice (0.8% lipid) and Alaska soles (1.0–1.2% lipid) can be classified as lean species, resulting in low 0.3–0.5 g ∑EPA+DHA/100 g muscle, although the fatty acid profiles of the extracted lipids were characterised by high amount of n‐3 fatty acids (33.2–47.3%). Arrowtooth flounder belong to the medium‐fat species (4.3%). Taurine was the most prevalent free amino acid; mean values ranging between 221 mg100 g^?1 and 247 mg100 g^?1 wet weight. The selenium content varied between 130 and 310 μg kg^?1 ww. Sensory attributes of Southern and Northern rock sole were comparable to plaice.     

Lipolytic and oxidative changes in Iberian dry-cured loin

This study was conducted using 61 Iberian pigs from four different genetic lines fattened under two different rearing systems. Fatty acid composition of neutral lipids (NL), polar lipids (PL) and free fatty acids (FFA) of the 61 fresh loins and their corresponding dry-cured loins and indices of lipid oxidation (hexanal, TBARS and rancid flavour) of the dry-cured loins were analyzed. Although the total amount of fatty acids from PL decreased most (89.77%), the fatty acid profile of FFA from dry-cured loin was more similar to that of NL from fresh loins. Monounsaturated fatty acids (MUFA) were the most abundant FFA type (260mg/100g muscle dry matter) followed by saturated fatty acid (SFA) (256mg/100g muscle dry matter) and polyunsaturated fatty acids (PUFA) (148mg/100g muscle dry matter). Neither genetic line nor rearing system showed any significant (P>0.05) effect on the decrease of fatty acids in the lipid fractions studied. The important decrease in PUFA from NL (43.70%) and PL (89%) was not reflected in higher oxidative indices in dry-cured loin. Neither PCA nor Pearson's correlation showed any clear relationships between lipolytic changes and oxidative indices.     

Amino acid stability in unpreserved and preserved minced capelin (Mallotus villosus)

Dark muscle tissue of farmed rainbow trout (Oncorhynchus mykiss Walbaum) was found to have a higher total lipid content than light muscle—73 vs 30 g kg^?1—which was mainly due to a higher content of neutral lipids. In accordance with this the phospholipid content in the dark muscle tissue was 322 g kg^?1 of total lipids compared with 569 g kg^?1 in light muscle tissue. Lipids from light muscle tissue contained higher percentages of polyunsaturated fatty acids than the dark muscle lipids, and docosahexaenoic acid was the major fatty acid present.     

Comparative lipid composition of porcine muscles at different anatomical locations

The influence of anatomical location on the intramuscular lipids was studied in Large White pigs. The amount of total, neutral and polar lipids and the composition of fatty acids of the above three fractions were determined for Longissimus dorsi (LD) at two points and Transversus abdominis (TA) and Biceps femoris (BF) taken from the two half carcasses of an animal. The symmetrical samples from the same animal had identical intramuscular lipid characteristics. The three muscles did not show significant differences in their total (2·8 to 2·4g/100g) and neutral (2·1 to 1·4g/100g) lipid contents. The amount of polar lipids was characteristic of every muscle (0·65 g, 0·84 g and 0·97 g per 100 g, respectively, in LD, BF and TA). The fatty acid composition of neutral lipids was influenced by the type of muscle. Polar lipid had similar fatty acid composition in the three muscles. The intramuscular lipids contained appreciable amounts of essential fatty acids of the family n-6; interestingly, a part of which (25% of EFA) was the long chain fatty acid (C20 and C22) located in the polar lipids.     

Seasonal variations in lipid composition of spanish wild rabbit (Oryctolagus cuniculus) meat

Four batches of wild rabbit (Oryctolagus cuniculus: winter, spring, summer and autumn) were caught at the end of the respective season of the year. A study of the meat chemical composition of these animals was carried out. The classes and amounts of total, apolar and polar lipid fractions, and their fatty acids, have been extensively studied. The total, apolar and polar lipid contents from the muscle of the four batches ranged from 37 to 14, 30-1 to 8–4 and 9–0 to 4–8 g kg^?1 FW respectively. Triglycerides accounted for more than 59% of the apolar lipids, and phosphatidylcholine and phosphatidyl-ethanolamine were the major phospholipids (>44% and >35% of total phospholipids, respectively). Almost always, 16:0, 18:0, 18:1 and 18:2 were the more abundant fatty acids of the total lipid fraction. Many seasonal differences may be observed in the fatty acid composition of total and apolar lipid fractions which are obviously related to the kinds of feed available in each season. One of the most significant differences is in 18:1 concentration. This fatty acid accounted for more than 50% in the apolar lipids from rabbits caught in autumn whereas the same fatty acid never reached 30% in other seasons. On the contrary, 18:2 and 20:0 showed a lower concentration in the autumn batch by comparison with those of the other seasons.     

Ripening of salted anchovy (Engraulis anchoita): development of lipid oxidation, colour and other sensorial characteristics

BACKGROUND: Changes in lipids are in general associated with quality deterioration, though earlier studies in anchovy indicate that the volatile compounds of importance to the characteristic flavour could be generated by lipid oxidation. The aim of the present paper was to study the changes in the fatty acid composition and the lipid oxidation of Engraulis anchoita during ripening and their relationship with the development of the typical sensorial characteristics. RESULTS: As a result of ripening, polyunsaturated fatty acids decrease from 4.27 to 2.42 and 2.00 g kg^?1 fatty acids in gutted fish and fillet, respectively. The most affected class of fatty acids was the n‐3 fatty acids, especially docosahexaenoic acid. Moreover, saturated fatty acids were the most stable to the process. 2‐Thiobarbituric acid reactive substances (TBARS) increased throughout ripening, and the use of fillets instead of gutted fish reduced this value. The a* value was the parameter most modified, showing a marked increase which correlates with the acquisition of a uniform pink colour. Sensory analysis did not show development of off‐odour or undesirable changes in colour during ripening. CONCLUSION: As a result of ripening, the fatty acid profile was modified and an increment of TBARS was observed. However, these changes did not lead to deterioration in the quality of the product. Copyright © 2010 Society of Chemical Industry     

Fatty acids profile of oil from nine varieties of Macadamia nut

The fatty acids profile and lipids content of the Macadamia integrifolia and Macadamia tetraphylla varieties and interspecies hybrids, M. integrifolia and M. tetraphylla were analyzed. Total lipids content ranged from 70.9 to 79.7 g of oil per 100 g^?1 dry-solids. Gas chromatography/mass spectrophotometry identified 20 fatty acids, the most abundant of which were oleic acid (40 to 51%), palmitoleic acid (24 to 36%), and palmitic acid (8.4 to 13.1%). Fatty acids concentration differed between varieties and hybrids (Multivariate analysis of variance, F = 13.89, p < 0.0001). A ratio of monounsaturated fatty acids:saturated fatty acid values ranged from 2.8 to 4.6. The Huatusco variety (M. integrifolia and M. tetraphylla) exhibited the highest percentage of lipids (79.7 g of oil per 100 g^?1 DS) and the highest monounsaturated fatty acids:saturated fatty acid (4.6), thus highlighted its potential applications within the food industry. The Cate variety (M. integrifolia and M. tetraphylla) had the lowest monounsaturated fatty acids:saturated fatty acid, suggesting potential uses in the cosmetics industry.     

LIPIDS AND FATTY ACIDS OF WILD EDIBLE MUSHROOMS OF THE GENUS BOLETUS

Fifteen species of wild edible mushrooms belonging to the genus Boletus (phylum Basidiomycota) were examined by high-performance thin-layer chromatographic (HP-TLC) analysis and gas chromatography–mass spectrometry (GC-MS) analysis for the presence of neutral, glyco-, phospholipids, betaine lipids and fatty acids. The most abundant fatty acids were oleic acid (9-18:1, 15–42%), linoleic acid (9,12-18:2, 38–58%) and palmitic acid (16:0, 7–17%), but a great variation of the ester composition from one to another one was found. A comparison of neutral lipids, glycolipids, polar lipids and fatty acid composition of four species was done. Diacylglyceryltrimethylhomoserine and phosphatidylcholine were found as major components among polar lipids. Chemical constituents were characterized by GC-MS, HP-TLC and other chemical methods. Biologic activity of some isolated compounds from the genus Boletus is also discussed.

PRACTICAL APPLICATIONS

Mushrooms are important wildlife food in the Mediterranean countries. The lipids of mushrooms, sampled from the Upper Galilee, Golan Heights and Mount Carmel areas, and also from the forest around Jerusalem, were examined. The benefits of including fatty acids in the diets of humans are well documented. Fatty acids play a major role in the functioning of the immune system and the maintenance of all hormonal systems in the body. Mushrooms from the genus Boletus are an excellent source of both fatty acids and neutral and polar lipids. Boletus mushrooms are one of the most popular treats in Israeli houses.     

Development of lipid oxidation during manufacturing of horse mackerel surimi

When fatty fish are transformed into surimi, lipid oxidation takes place, decreasing the quality of the product. This study was aimed to identify the critical stages of the process in terms of the development of lipid oxidation. Horse mackerels were transformed into surimi on a pilot line and samples taken (hand‐skinned fillets = minced fillets, mince, washed and refined minces, paste, surimi and washing water). Most of the lipids were removed during the process and neutral lipids were lost in higher proportion than polar lipids. As a consequence, total lipids of surimi contained more polyunsaturated fatty acids (338 ± 19 g kg^?1) than total lipids of the minced fillets (220 ± 8 g kg^?1). Thiobarbituric acid reactive substances (TBARS) was higher in the minced fillets than in the mince because less subcutaneous fat and dark muscle were removed during hand‐mincing, indicating that the settings of the skinning–deboning machine can strongly influence the final quality of the product. Concentrations of lipid oxidation products increased significantly during the next stages of surimi processing. The increase was more pronounced for TBARS than hydroperoxides. Concentrations in hydroperoxides were similar in mince and washed mince (15.3 ± 2.8 and 16.6 ± 2.8 mmoles kg^?1 lipid) and increased in refined mince (29.6 ± 2.8 mmoles kg^?1 lipid). TBARS accounted for 2.7 ± 1.0 mg kg^?1 lipid in mince, 40.4 ± 2.3 mg kg^?1 lipid in washed mince and 237 ± 7 mg kg^?1 lipid in refined mince. Hydroperoxides and TBARS were found in appreciable amounts in washing water (76.9 ± 4.7 mmoles kg^?1 lipid and 479 ± 8 mg kg^?1 lipid respectively), when they decreased in surimi (27.3 ± 3.8 mmoles kg^?1 lipid and 44.2 ± 0.8 mg kg^?1 lipid respectively) compared with refined mince. This shows that the last dewatering stage is crucial to ensure surimi quality. Copyright © 2005 Society of Chemical Industry     

Original article: Extraction of lipid from scallop (Patinopecten yessoensis) viscera by enzyme‐assisted solvent and supercritical carbon dioxide methods

In the present study, lipid was extracted from scallop (Patinopecten yessoensis) viscera by using the enzyme‐assisted solvent method and the supercritical carbon dioxide (SC‐CO₂) method. Soxhlet extraction with ethyl ether produced a yield of 23.7 ± 0.6 g of lipid 100 g^?1 of dry matter. Enzyme‐assisted solvent extraction allowed recovering 60.6 ± 1.5% of P. yessoensis viscera lipid from the samples treated with papain, whereas a lipid recovery rate of 78.3 ± 0.6% was achieved by SC‐CO₂ extraction. The lipid extracted was divided into the unsaponifiable fraction (sterol) and the saponifiable fraction (fatty acid) and analysed by gas chromatography mass spectrometry. Results indicated that the fatty acid composition and sterol composition for lipids extracted by different methods were slightly different. Eicosapentaenoic acid and docosahexaenoic acid were dominant polyunsaturated fatty acids accounting for 35–40% of the total fatty acid.     

Effect of rearing system on muscle lipids of gilts and castrated male pigs

The objective of this study was to investigate the polar and neutral lipid fatty acid composition of pig muscle as influenced by rearing conditions and sex. A total of 120 Hampshire crossbreeds were divided in two groups, one reared free-range in a strip grazing fashion and one reared indoors in a large pen (120 m(2)). Free-range rearing produced a more unsaturated fatty acid composition (M. biceps femoris) in the neutral lipids, although the effect was small. In the polar lipids the effect of rearing condition was sex dependent. In the muscle of free-range gilts, there was a higher level of C18:2 n-6, compared with indoor gilts, indoor castrates, and free-range castrates. Moreover, muscle of gilts irrespective of rearing condition, had a higher level of the C?20 polyunsaturated fatty acids in the polar lipids (16.75 and 14.60, respectively). Thus, we suggest that the difference between castrates and gilts with respect to fatty acid composition in the polar lipids, might be affected by rearing condition.     

白卜鲔下脚料中脂质成分分析

对白卜鲔下脚料中的脂质成分及其脂肪酸组成进行了分析。结果表明:白卜鲔加工下脚料中含有大量的脂质成分,鱼肝中粗脂肪含量达到了48.8%(以干基计),鱼头中的粗脂肪含量达到33.3%(以干基计);鱼头中的脂质以极性脂肪为主,而鱼肝中的脂质则以中性脂肪为主,两者的极性脂质中磷脂是主要成分;鱼头和鱼肝脂质中的脂肪酸组成基本相似,不饱和脂肪酸含量较高,EPA和DHA的总含量分别为13.8%和7.77%。     

Lipids and fatty acids of a whitefish (Coregonus albula) flesh and roe

The total lipids of whitefish flesh and roe averaged 3.0 and 9.8% fresh weight, respectively. Although neutral lipids dominated in both tissues the polar lipid content of fresh roe was unexceptionally high (2.5%). The fatty acid patterns of the total lipids from flesh and roe and of neutral lipids were similar to each other. Polyenoic acids constituted about half of the total fatty acids and monoenoic and saturated components existed in equal amounts. The calculated iodine values for the total lipids from flesh and roe indicated a slightly higher degree of unsaturation for roe fatty acids. The polar lipids were enriched in polyenoic and saturated fatty acids. Similarities in the composition and content of fatty acids from flesh and roe suggest that storage problems, apparent as a rancidity of roe products, may result from the high content of polar lipids readily hydrolysed during storage.     

Spirulina: A source of dietary gamma-linolenic acid?

Spirulina powders obtained from different commercial sources contained 23.6–38.0 mg g^?1 DM as long-chain fatty acids and 3.4–6.0 mg g^?1 DM as y-linolenic acid (6, 9, 12-octadecatrienoic acid). However, γ-linolenic acid constituted up to 40% of the total fatty acids within the isolated galactolipids. Unesterified fatty acids accounted for 8.4–66.9% of the fatty acids recovered from the different samples; the remaining fatty acids were in glycerolipids. There was also a wide variation in the contents of photosynthetic pigments among the different preparations. Spirulina was four-fold more expensive than evening primrose oil as a source of a-linolenic acid to supplement human diets. Since α-linolenic acid (9, 12, 15-octadecatrienoic acid), (E)-3 hexa-decenoate, 3-sn-phosphatidylcholineand 3-sn-phosphatidyl ethanol-amine were not detected in the lipid extracts, none of the samples was significantly adulterated by eucaryotic algae. From an analysis of the extracted lipids it was possible to make some predictions both about the manner in which the cells were cultured and the post-harvest treatment of the preparations.     

Muscle lipids, vitamins E and A, and lipid oxidation as affected by diet and RN genotype in female and castrated male Hampshire crossbreed pigs

The objectives of this study were to investigate the polar and neutral lipid fatty acid composition, content of retinol, -tocopherol, γ-tocopherol and level of oxidation of the pig muscle (M. longissimus dorsi). Female and castrated male Hampshire crossbreeds were produced in two systems. One group was raised indoors with a more polyunsaturated diet and the other raised outdoors with a more saturated diet. The level of polyunsaturated fatty acids in muscle was higher in the indoor females compared with the outdoor females, indoor castrated males and outdoor castrated males. The increased level of polyunsaturated fatty acids in the muscle, which was accompanied by a relatively low content of -tocopherol, increased the susceptibility to lipid oxidation in the form of MDA (malondialdehyde) in the indoor female pigs. Finally, the level of polyunsaturated fatty acids in the polar lipids was affected by the RN genotype, and this difference was dependent on sex. In conclusion, diet has a major effect on the fatty acid composition and oxidation stability in pork muscle, but additional factors such as sex and RN genotype might also contribute.     

Epicatechin derivatives and fatty acid composition of a traditional product made in Sikkim from leaves of Camellia sinensis

A traditional product of Camellia sinensis leaves was recorded in tribal areas of Sikkim State, India. The product was analysed for its epicatechin derivatives, and for its neutral lipid, glycolipid and phospholipid contents together with their fatty acid compositions. (–)– Epigallocatechin-3-gallate (EGCG) was the main polyphenolic constituent present in this traditional product, accounting for 742 g kg^?1 of total epicatechin derivatives. Glycolipids, which account for 570 g kg^?1 of total lipid, contained a significantly greater amount of linolenic acid (C 18: 3, 546 g kg^?1 of glycolipid) than the neutral lipids or phospholipids. Palmitic (C 16:0) and linoleic (C18:2) acids were in greater proportion in the phospholipid fraction, while myristic (C14:0) and lauric (C12:0) were abundant in the neutral lipid. Since EGCG is a known antimutagenic and anticarcinogenic agent, this traditional tea product may have considerable pharmacological significance.     

Chemical composition,protein fractionation,essential amino acid potential and antimetabolic constituents of an unconventional legume,Gila bean (Entada phaseoloides Merrill) seed kernel

Physical characteristics of pods and seeds, proximate composition, different protein fractionation, SDS‐PAGE analysis of proteins, amino acid composition, starch content, fatty acid profiles and various antimetabolic substances of Gila bean (Entada phaseoloides Merrill) were studied. The pod length and the number of seeds per pod ranged from 55 to 90 cm and from 5 to 11 respectively. The kernel comprised 66.1% of the seed weight (18.41 ± 1.14 g). The seed kernels contained 256.7 g kg^?1 crude protein, 108.1 g kg^?1 lipid, 27.3 g kg^?1 ash and a high content of carbohydrate (585.7 g kg^?1). The levels of potassium, phosphorus, zinc and iron were similar to those in conventional pulses. Among the different protein fractions of seed kernels, albumins constituted the major storage proteins (69.7%). The kernel proteins were rich in essential amino acids, particularly sulphur‐containing amino acids, and their values appeared to be higher than the FAO/WHO (1990) reference protein for a 2–5‐year‐old growing child and soybean, and comparable to hen egg. Seed kernel lipids contained high levels of unsaturated fatty acids, oleic and linoleic acids, which accounted for 83% of the total fatty acid recovered. The kernel exhibited high trypsin and chymotrypsin inhibitor activities (96.65 mg TI g^?1 and 30.02 CIU mg^?1 sample respectively) in addition to containing phenolics, phytic acid, lectins and oligosaccharides. Another major toxic constituent was identified as a group of triterpenoid saponins (3.21%), which had high haemolytic activity (HeU) against cattle erythrocytes and caused high mortality in fish. The in vitro digestibility of the kernel protein was low (67%). © 2001 Society of Chemical Industry     

Compositional characteristics of muscle and visceral oil from steelhead trout and their oxidative stability

The quality of lipid from steelhead trout viscera, a byproduct of steelhead trout industry, was evaluated and compared with that of the muscle. Steelhead trout viscera had a higher lipid content than muscle and the visceral oil differed from muscle oil in its lipid class composition. Neutral lipids, mainly triacylglycerols (TAG), comprised the major lipid class in both muscle and visceral lipid. However, as expected, muscle contained a remarkably higher level of phospholipids (PL) than viscera, and the ratio of total neutral lipids to polar lipids was lower in muscle than in viscera. Visceral and muscle lipid had similar fatty acid compositions, with the concentration of muscle polyunsaturated fatty acids (PUFA) slightly higher than that of visceral PUFA. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were the major n-3 PUFA present in both muscle and visceral lipid; docosapentaenoic acid (DPA) was present at about 1.61–1.76%. With respect to minor components, muscle lipid had higher α-tocopherol and total carotenoids contents than visceral lipid. Oxidative stability of visceral and muscle lipid, as determined by conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS), showed that visceral lipid was more stable against oxidation than muscle lipid, probably due to their different lipid profiles. Besides, carotenoids, which were present more abundantly in muscle, might have acted as prooxidants and therefore, decreased the oxidative stability of muscle lipid. These results suggest that steelhead trout viscera may serve as a good source of lipid and could be utilized for production of omega-3 oils.     

Influence of cold shock on the fatty-acid composition of different lipid classes of the food-borne pathogenListeria monocytogenes

Listeria monocytogenes, a Gram-positive pathogenic food-borne bacterium, is notably resistant to chill and osmotic stress.Listeriais characterized by an unusual proportion of branched-chain fatty acid (>85%), primarily anteiso-15:0 and anteiso-17:0. Cells grown at lower temperatures contain significantly less anteiso-17:0 than those grown at higher temperature. Cold-shock studies were performed to determine the mechanisms by whichListeriaperceives cold shock and changes its membrane composition. This study made three comparisons: (i) The lipids ofL. monocytogenescultured at 30°C were compared with those of cells grown at 6°C. Extraction of total lipids yielded 4–4.5 and 6.5–7 mg ml^-1cell mass (wet weight), respectively. Total lipids contained 3–4% and 2–2.5% lipid phosphorus, respectively, reflecting a higher content of neutral lipids in cells grown at 6°C. (ii) The fatty-acid compositions of different lipid classes (total lipids, the major phospholipid, and the glyco-containing phospholipid class) all responded by increasing the proportion of anteiso-15:0 fatty acids at low temperature. (iii) The fatty-acid composition of the neutral and polar lipids from the early stage of the temperature response (3 days at 5°C) and the effect of chloramphenicol or cerulenin were examined. The results indicated that anteiso-15:0 fatty acids were selectively increased in the newly synthesized neutral lipids, but the polar lipids did not show an apparent change in fatty-acid composition. These changes in membrane fatty-acid composition did not require new protein synthesis (the process was chloramphenicol insensitive) and the existing condensing enzyme activity was necessary to the fatty-acid response (the process was cerulenin sensitive).