Effects of cooking methods on the proximate,mineral and fatty acid composition of European eel (Anguilla anguilla)

The influence of microwave cooking and traditional cooking methods such as baking, grilling and frying on the nutritional composition of eels (Anguilla anguilla) was studied. All methods reduced moisture and increased the protein and fat content. Although the potassium and sodium content of fish cooked by different methods decreased significantly (P = 0.000), the calcium and magnesium content increased. The zinc content of the fish was not affected by cooking. The manganese and iron content significantly increased only in fried fish. The copper content was increased by grilling and microwave cooking. The proportion of saturated fatty acids and monounsaturated fatty acids in cooked fish decreased. Omega‐3 polyunsaturated fatty acids were increased by all cooking methods. The grilling and microwave‐cooking methods were the most suitable considering the n3/n6 ratio and eicosapentaenoic acid levels. The increase in the docosahexaenoic acid level of fried fish enhanced its nutritional value.     

Comparative assessment of proximate composition,physicochemical parameters,fatty acid profile and mineral content in farmed and wild rainbow trout (Oncorhynchus mykiss)

This study was conducted to determine differences between farmed and wild rainbow trout in terms of proximate and fatty acid composition, physicochemical parameters and mineral content. Fat content of farmed fish fillets was higher, while moisture content was lower than wild fish. However, wild fish had higher pH value and water‐holding capacity comparing to farmed fish. The muscle lipids of farmed fish contained higher proportions of 20:0, 18:1n‐9 and 20:1n‐9; and lower proportions of 18:2n‐6, 20:2cis, 18:3n‐3, 20:3n‐6, 20:4n‐6, 20:5n‐3 and 22:6n‐3 fatty acids than wild fish. The percentage of total saturated fatty acids (SFAs) was similar in both fish. Total polyunsaturated fatty acids (PUFAs), n‐3 PUFAs and n‐3/n‐6 PUFAs ratio were higher in the wild fish comparing to farmed fish, whereas its total monounsaturated fatty acids (MUFAs) and n‐6 PUFAs contents were lower. Among the seventeen minerals analysed in fish flesh, differences existed between farmed and wild rainbow trout in Ca and Fe contents. Moreover, toxic trace minerals (As, Cd, Pb and Hg) were all present in amounts below their toxic levels. The differences observed between farmed and wild fish may be attributed to the diet constituents and environmental conditions of the fish.     

Variation of major fatty acids in F8 generation of opium poppy (Papaver somniferum × Papaver setigerum) genotypes

The fatty acid compositions in F₈ genotypes of a cross between Papaver somniferum×Papaver setigerum were studied. The oil content in both species was quite variable, ie 38·0% in P setigerum and 47·8% in P somniferum, while C18 fatty acids were quite comparable. The F₈ genotypes had higher oil contents (>40%) and fatty acid concentrations than the parental species. Linoleic acid ranged between 68% (BRO 54) and 74·4% (BRO 59) and oleic acid varied between 13·6% (BRO 65) and 20·3% (BRO 54). High oleic desaturation ratio (ODR, >0·79) and C18 polyunsaturated fatty acid (>87%) with very low C18: 3 (0·37±0·01) indicate the possibility of using poppy oil for the edible oil industry. Oleic (18:1) acid was not correlated with the other fatty acids, except for significant negative correlation with linoleic (C18: 2) acid. © 1998 SCI.     

Variation in nutrient composition of Australian retail potatoes over a 12-month period

‘Pontiac’, ‘Sebago’ and potatoes marketed under the general name of New potatoes were purchased from retail outlets in Sydney, Australia every 2 weeks over a 12-month period during 1982–83 to determine the change in composition over a season. Data are presented for water, vitamin C, starch, sugars (fructose, glucose and sucrose), dietary fibre, protein, fat, organic acids (malic, citric and oxalic acids), ash, carotenes, thiamin, riboflavin, niacin, potassium, sodium, calcium, magnesium, iron and zinc levels, edible weight and energy content. The level of vitamin C varied throughout the year from 10 to 23 mg 100 g^?1 for ‘Pontiac’, 14 to 29 mg 100 g^?1 for ‘Sebago’ and 16 to 32 mg 100 g^?1 for New potatoes with the lowest values occurring in August to September (late winter to early spring) and the highest values in December to January (mid summer). Substantial variations also occurred in the water content, which was higher, and the level of starch and hence energy content, which was lower, during the cooler months of the year. Smaller changes were noted for niacin and thiamin which were lower and sugars which were higher during the winter period.     

A review of chemical composition and nutritional value of wild‐growing and cultivated mushrooms

Fruit bodies of about 200 mushroom species are consumed throughout the world, preferably as a delicacy. Knowledge of their chemical composition, nutritional value and health‐promoting effects has expanded dynamically during the last few years. Dry matter (DM) is low: commonly about 100 g kg^?1. The usual contents of protein, lipids and ash are 200–250, 20–30 and 80–120 g kg^?1 DM, respectively. Various carbohydrates form the remaining DM. Nevertheless, great variations occur both among and within species. Energy is low, usually 350–400 kcal kg^?1 of fresh fruit bodies. The nutritional contribution of mushroom protein derived from earlier data seems to be overestimated. Fat content is low with markedly prevailing in linoleic acid and oleic acid, while the proportion of n‐3 fatty acids is nutritionally marginal. The main carbohydrates are chitin, glycogen, trehalose and mannitol. Information on fibre content and composition is limited. Health‐promoting β‐glucans are an auspicious group of polysaccharides. High potassium content is characteristic of mushrooms. Several species can accumulate very high levels of both detrimental trace elements, particularly cadmium and mercury, and radiocaesium isotopes if growing on heavily polluted substrates. Mushrooms seem to be a considerable source of ergosterol, provitamin D₂, and phenolids with antioxidative properties. Hundreds of flavour constituents have been identified, particularly with eight‐carbon aliphatic chains. Data on changes of mushroom components under various preservation conditions and culinary treatments have been fragmentary. Even more limited is knowledge of nutrient bioavailability. Copyright © 2012 Society of Chemical Industry     

The proximate chemical composition and the amino acid content of some Nigerian oil seeds

Seven samples of some Nigerian oil seeds have been studied with respect to their proximate composition, calcium and phosphorus contents as well as the amino acid composition which was determined by column chromatography. Three of the groundnut samples were processed in the laboratory. These were then compared with a commercial groundnut cake. The African oil bean seeds, the conophor nuts and the soya beans obtained locally were processed in the laboratory. The chemical composition of the oil seed meals were with few exceptions similar to those reported in the literature. The tryptophan and sulphur amino acid contents of the conophor nuts were extremely high compared with the other oil seeds in which the sulphur amino acids were the limiting ones. The lysine contents of the African oil beans and the conophor nuts were exceptionally high compared with others. Glutamic acid followed by aspartic acid and arginine levels were generally high in each of the oil seeds. The implication of these findings are fully discussed.     

三种洋葱营养成分分析

对三种洋葱的主要营养成分、矿物质和黄酮类化合物含量进行分析研究,并探讨黄酮类化合物含量与抗氧化的关系。三种洋葱中水分含量为88.3%～92.7%,碳水化合物为7.73%～8.56%,蛋白质为1.12%～1.71%,脂肪为0.23%～0.41%,其中,白皮洋葱的脂肪含量较高,适合作为提取洋葱油的原料。三种洋葱中黄酮类化合物含量为592.3～913.2mg/kg,紫皮洋葱的黄酮类化合物含量最高,适合作为提取黄酮类化合物的原料,而且紫皮洋葱的产量较高,种植面积较大,很有开发前景;三种洋葱的黄酮类化合物含量与总的抗氧化能力没有相关性。三种洋葱矿物质元素组成相似,钾含量最高,铜含量最低。     

Walnuts (Juglans regia L): proximate composition,protein solubility,protein amino acid composition and protein in vitro digestibility

Walnuts contained 16.66% protein and 66.90% lipids on a dry weight basis. Non‐protein nitrogen values ranged from 6.24 to 8.45% of the total nitrogen when the trichloroacetic acid concentration was varied within the range 0.25–1.0 M . Albumin, globulin, prolamin and glutelin respectively accounted for 6.81, 17.57, 5.33 and 70.11% of the total walnut proteins. Walnut proteins were minimally soluble at pH 4.0. The majority of total walnut protein polypeptides had estimated molecular weights in the range 12 000–67 000. The Stokes radius of the major protein in walnuts (glutelin fraction) was 66.44 ± 1.39 Å. Lysine was the first limiting essential amino acid in total walnut proteins as well as in the globulin and glutelin fractions. Leucine and methionine plus cysteine were the second limiting essential amino acids respectively for the prolamin and albumin fractions. Hydrophobic and acidic amino acids dominated the amino acid composition in all protein fractions. Native and heat‐denatured walnut glutelins were easily hydrolysed by trypsin, chymotrypsin and pepsin in vitro. © 2000 Society of Chemical Industry     

Effect of different precooking methods on chemical composition and lipid damage of silver carp (Hypophthalmichthys molitrix) muscle

The influence of three precooking methods (steaming, oven‐baking and microwave‐cooking) on the chemical composition and lipid quality of silver carp fillets was evaluated. The changes in protein, fat and moisture were found to be significant for all the treatments (P ≤ 0.05). The iron content in the samples subjected to steam‐cooking increased; however, the other precooking methods did not change the mineral contents (P ≥ 0.05). The free fatty acid content of the fillets did not change by the different precooking methods, while thiobarbituric acid (TBA) values increased for oven‐ and microwave‐cooked fillets and remained constant in the steam‐cooked samples. Conjugated diene and browning colour formation levels significantly increased in the oven‐baked fillets. Oven‐baking and microwave‐cooking marginally affected the fatty acid composition of the silver carp. On comparing the raw and precooked fillets, steam‐cooking was found to be the best precooking method on retaining nutritional constituents.     

The chemical composition and some physical properties of a water-soluble gum from Prosopis africana seeds

A water‐soluble gum was extracted from the endocarp capsule of the seed coat of Prosopis africana. The gum yield varied substantially with the method of dehulling. Maximum yield was obtained after boiling in 0.1 m Na₂CO₃ for 4 h. The effects of two different gum concentrations on the rheological properties of gum solutions were examined. The gum formed viscous solutions at low concentrations and exhibited stable viscosity in the pH range 6.0–8.0. Chemical analyses showed that the purified gum had a composition of 2.4% fat, 1.04% protein, 21.5% crude fibre and a gelation concentration of at least 10%. Galactose and mannose were the major polysaccharides identified. Large reductions in viscosity were observed with the addition of various concentrations of Na⁺ salts. The activation energies of flow for 2 and 3% gum solutions were in the range of 19.2–22.8 kJ mol^?1 and were characteristic of systems with little intra‐ and intermolecular interactions.     

Comparative study of proximate composition and amino acid in farmed and wild Pseudobagrus ussuriensis muscles

The proximate composition and amino acid compositions of the muscle of wild and farmed Pseudobagrus ussuriensis were compared. The lipid content of the farmed fish was significantly higher, while moisture content was significantly lower, than those of the wild fish. Pseudobagrus ussuriensis protein has a well‐balanced amino acid composition. The percentages of total amino acids, essential amino acids, nonessential amino acids and delicious amino acids were significantly higher in the wild than those in farmed fish. The ratios of W_EAA to W_TAA (42.78%–43.02%) and W_EAA to W_NEAA (85.52%–87.74%) were comparable to the reference values of 40% and above 60% recommended by FAO/WHO. According to the amino acid scores, methionine would have been described as the first limiting amino acid, and Lys had the highest score for the protein in both wild and farmed Pseudobagrus ussuriensis. This study shows that Pseudobagrus ussuriensis under investigation have high nutritional qualities and are good protein resources.     

Effect of season and proximate composition on the Br,As, Cd and Pb contents in different kinds of key foods consumed in Portugal

On the basis of a Total Diet Study, the Br, As, Cd and Pb contents in relevant food groups consumed in Portugal were determined. The studied groups were meat products, fatty fish, lean fish, shellfish, cephalopods, fresh and dried fruit, crucifers and other vegetables. It was observed that the concentrations of As, Br, Cd and Pb in fruit, vegetables and meat products were much lower than in seafood. Fresh fruit exhibited the lowest elemental contents. The concentrations of As, Br, Cd and Pb did not show any dependence on season. With respect to proximate composition, elemental content dependence on protein or ash was weak. PCA showed relevant associations: between Br and ash contents in fatty fish; between Cd, Pb and protein contents in crucifers; and between As, fat and protein contents in the other vegetables group. Therefore, the effect of the proximate composition on the studied elemental contents warrants investigation.     

Kigelia africana seed: proximate,mineral, vitamin E,fibre, amino acid and fatty acid composition

Research reports on the ethnomedical and pharmacological potential of Kigelia africana extracts. In this study, the nutritional potential of K. africana seed and seed oil was evaluated by chemical analyses. Organic matter and ash constituted 915.23 ± 7.98 g kg^?1 DM and 49.05 ± 4.55 g kg^?1 DM of the seed mass, respectively. Oil constituted 492.2 g kg^?1 DM of the seed mass with oleic acid, linoleic acid and α‐linolenic acid constituting 17.6%, 12.9% and 54.3%, respectively, of the seed oil. Vitamin E concentration was 0.94 ± 0.25 μg g^?1. Crude protein was 357.35 ± 3.39 g kg^?1 DM. Arginine (6.14 ± 0.31 g per 100 g) as the most abundant amino acid and hydroxyproline (0.11 ± 0.06 g per 100 g) the least. Phosphorus (1123.2 mg per 100 g) and calcium (56.1 mg per 100 g) were, respectively, the most and least abundant minerals. Gross energy was 29.6 ± 0.06 MJ kg^?1. Kigelia africana seeds could be exploited as nutrient‐dense dietary supplement rich in protein, oleic acid and essential fatty acids.     

Composition and functional properties of raw and electron beam-irradiated Mucuna pruriens seeds

The proximate, nutritional and functional properties of raw and electron beam-irradiated (0–30 kGy) Mucuna seeds were investigated. Irradiation increased crude protein and crude carbohydrates significantly than crude lipid, crude fibre and energy. Raw seeds were rich in minerals and were not affected by irradiation except for magnesium and phosphorus. Amino acids of raw seeds were comparable to soyabean and FAO/WHO reference pattern and except for 30 kGy, no significant changes were seen in amino acid profile. Raw seeds were rich in unsaturated fatty acids and some of them decreased on irradiation, while linoleic acid steadily elevated (0–14.35 mg g⁻¹ lipid). In vitro protein digestibility was dose dependent and significantly increased up to 15 kGy. Water and oil absorption capacities and foaming capacity significantly increased on irradiation, while protein solubility decreased (15 and 30 kGy) with an improvement of gelation property of seed flour. The cooking time of seeds significantly reduced on irradiation.     

Fatty acid profile and proximate composition of Pacific mullet (Mugil so‐iuy) caught in the Black Sea

This study demonstrates proximate composition and fatty acid profile of Pacific mullet caught in Turkey. The highest moisture and protein contents were observed with muscle tissues as 83.74 and 10.52%, while the highest fat and ash contents were attributed to female gonads as 11.80 and 0.94%, respectively, with a significant variation amongst months (P < 0.05). Significant variation (P < 0.05) usually occurred amongst months within the same sex for total saturated fatty acids ( ∑ SFA), monosaturated fatty acids ( ∑ MUFA), polyunsaturated fatty acids ( ∑ PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in muscle, although overall mean values between sexes were not found significant. Except for EPA, no variation observed for gonads while significant changes occurred (P < 0.05) with liver samples amongst months. Overall total values of ∑ SFA, ∑ MUFA, ∑ PUFA, DHA and EPA in muscle samples were 29.59, 29.26, 18.06 and 4.48%, respectively, while in gonads ranged as 30.26–33.23%, 35.17–37.47%, 11.87–14.88%, 4.38–5.34% and 3.02–5.02%. These FAs were 21.57–33.11%, 32.89–50.96%, 14.78–20.08%, 0.89–9.94% and 5.85–9.54% for liver, respectively. The results of this study showed that muscle and gonads of Pacific mullet were rich in n‐3 PUFA, especially, EPA, DHA, increasing the value of this species for human consumption.     

Comparison of proximate composition,amino acid and fatty acid profiles in wild,pond‐ and cage‐cultured longsnout catfish (Leiocassis longirostris)

The proximate composition, amino acid and fatty acid profiles in the fillets of wild, pond‐ and cage‐cultured longsnout catfish (Leiocassis longirostris) were determined to identify nutritional differences. Wild fish showed higher (P < 0.05) moisture and viscerosomatic index (VSI), but lower (P < 0.05) protein, ash and gross energy than cage‐cultured fish. Pond‐cultured fish contained lower (P < 0.05) protein and ash contents, but higher VSI compared to cage‐cultured fish. The amino acid of glycine content was higher (P < 0.05) in wild fish than in pond‐ and cage‐cultured fish. Most of the fatty acids had a significant difference among all fish groups. The percentages of total polyunsaturated fatty acids (∑ PUFAs) were higher (P < 0.05) in wild and pond‐cultured fish than in cage‐cultured fish. Pond‐cultured fish had higher (P < 0.05) ∑ n‐3 PUFAs, eicosapentaenoic acid (EPA), docosahxaenoic acid (DHA) and ∑ n‐3/∑ n‐6 PUFAs ratio than wild and cage‐cultured fish. The differences among the wild, pond‐ and cage‐cultured fish may be attributed to dietary components and environmental conditions of the fish.     

Seasonal changes of proximate composition and fatty acids of farmed dusky grouper (Epinephelus marginatus Lowe, 1834)

The aim of this work was to determine the seasonality of nutrient profiles of dusky grouper (Epinephelus marginatus Lowe, 1834) cultured in a cage to improve knowledge on its nutritional composition. Fish (n = 735) were reared in a circular polyethylene floating cage for a 19‐month experimental period and provided a commercial pelleted feed once a day with a total daily ration of 1% wet body weight. Fish were sampled every 3–4 months, and biometric parameters as well as muscle composition were determined. The edible proportion of fish increased slightly with culture time. The flesh showed low lipid content, similar to those reported for wild grouper. Biometric indices, muscle proximate composition and fatty acid profiles were significantly affected by seasonality, that is lipids and monounsaturated fatty acids increased during summer, in parallel with the decline of polyunsaturated fatty acids.     

Determination of proximate composition,fatty acid content and amino acid profile of five lesser‐common sea organisms from the Mediterranean Sea

Proximate composition, fatty acid and amino acid analysis of an echinoderm (Paracentrotus lividus), a crustacean (Penaeus kerathurus), a tunicate (Microcosmus sulcatus), and two gastropod molluscs (Littorina littorea and Patella coerulea) were determined. All organisms except M. sulcatus, were found to be good protein sources. P. lividus contained on average 15.1 g/100 g, P. kerathurus 15.6 g/100 g, L. littorea 8.3 g/100 g and P. coerulea 9.2 g/100 g protein. The crustacean contained high percentages of n‐3 fatty acids (28.3 g/100 g fatty acids), the tunicate high percentages of saturated fatty acids (62.2 g/100 g fatty acids) while the gastropod molluscs and the echinoderm had a balanced content of all fatty acid families. The most abundant amino acid in P. kerathurus, M. sulcatus, L. littorea and P. coerulea was glutamic acid (11.13 ± 0.9, 1.05 ± 0.3, 5.39 ± 0.3, 5.55 ± 0.8 g/100 g freeze‐dried sample respectively), while glycine was the most abundant amino acid in P. lividus (10.34 ± 1.0 g/100g freeze‐dried sample).