Showing papers in "Food Chemistry in 1993"
TL;DR: The literature on the protein content, amino acid composition, fractionation, and functional properties of flaxseed proteins is reviewed and summarized in this article, where the discussion on the fractionation centers on the methods for isolation of the various protein fractions and on the physico-chemical characteristics of high and low-molecular-weight fractions.
Abstract: The literature on the protein content, amino-acid composition, fractionation, and functional properties of flaxseed proteins is reviewed and summarized. The discussion on the fractionation centers on the methods for isolation of the various protein fractions and on the physico-chemical characteristics of high- and low-molecular-weight fractions. Most interesting are the favorable functional properties of flaxseed proteins and the wide range of potential products in which they can be incorporated.
201 citations
168 citations
TL;DR: In this paper, four varieties of dry beans (Phaseolus vulgaris ) grown in four different areas of Burundi were analyzed for moisture, protein, fat, ash, mineral (potassium, calcium, magnesium, iron, copper, zinc, and phosphorus), essential amino acids (isoleucine, leucine and lysine, methionine, phenylalanine, threonine, valine) and antinutritional factors (raffinose oligosaccharide, trypsin inhibitor, hemagglutinin, t
Abstract: Four varieties of dry beans ( Phaseolus vulgaris ) grown in four different areas of Burundi were analyzed for moisture, protein, fat, ash, mineral (potassium, calcium, magnesium, iron, copper, zinc, and phosphorus), essential amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine) and antinutritional factors (raffinose oligosaccharide, trypsin inhibitor, hemagglutinin, tannin and phytic acid) contents. In-vitro digestibility of dry bean proteins was also evaluated. The concentrations observed for the proximate composition, protein quality, and antinutritional factors varied significantly ( P −3 /g, 2·15 HU × 10 −3 /mg, 14·99 mg catechin equivalent/g and 16·50 mg/g. The levels obtained for different nutrients (except for some minerals) and antinutrients were in agreement with those found in dry beans in other areas of the world. Protein digestibility ranged from 67·47% (Calima variety from Kirimiro) to 71·99% (A410 variety from Imbo). These values were comparable to those obtained in other countries. Statistical analyses of data confirmed that nutrient content, protein digestibility and undesirable factors were influenced by both variety and locality. Relationships between some dry bean nutrients and between antinutritional factors and protein digestibility were also observed.
164 citations
TL;DR: In this paper, the proximate chemical composition of Turkish N. sativa L. seeds was investigated, and the compositions of fatty acids and sterols of the extracted oil were studied.
Abstract: Nigella sativa L. is an annual herbaceous plant which is cultivated for its seeds and is classified as an edible plant. The proximate chemical composition of Turkish N. sativa L. seeds was investigated. The compositions of fatty acids and sterols of the extracted oil were studied. The contents of total polyphenols and tocopherols of the oil were also determined, and an analysis of water-soluble vitamins and minerals in the seeds was carried out.
161 citations
TL;DR: Sensory evaluation of cooked fillet from fresh, 4-days frozen, 5-weeks frozen (−18°C) and traditionally smoked fresh fish was performed, and results indicated a combined effect according to vitamin E and n-3 PUFA contents.
Abstract: Atlantic salmon (Salmo salar) were fed three dietary levels of n-3 polyunsaturated fatty acids (PUFA) (1.0, 2.5 and 5.0% of the diets at 17% feed lipid level), each with two levels of vitamin E supplementation (0 and 300 mg α-tocopherol acetate/kg diet). The varying dietary n-3 PUFA contents were achieved by using soybean oil, capelin oil and sardine oil, respectively. Sensory evaluation of cooked fillet from fresh, 4-days frozen, 5-weeks frozen (−18°C) and traditionally smoked fresh fish was performed.
Fillet proximate composition did not differ between high-quality cultured and wild Atlantic salmon. The total lipid fatty acid composition and vitamin-E content of the fillets were highly influenced by the fish diets. The vitamin-E content of the fillets did not influence the fatty acid composition.
Significant differences were found for 7 of 14 sensory parameters when comparing for homogeneity between the dietary groups. Rancid flavour was significantly higher in fish raised on a high n-3 PUFA and low vitamin-E diet. The results indicated a combined effect according to vitamin E and n-3 PUFA contents. Coloration of the fillet seemed to depend upon lipid quality and vitamin E, in addition to the feed content of pigments. The differences in fatty acid composition of the fillets caused differences in the sensory perception of fattiness, juiciness and taste intensity.
Twelve of the sensory parameters showed significant differences between treatments. The freshly sampled fish was most white, tasted less intense, was most juicy and least firm. The smoked fish showed most coloration, least taste of soya, herring, rancidity and off-flavour, probably as a masking effect of the smoking procedure.
Several sensory parameters were affected by freezing and storage, including decreased whiteness and increased colour strength, taste intensity, rancid flavour and off-flavour.
156 citations
154 citations
TL;DR: The seed of an important food crop, indigenous to the Andean region of Latin America, called quinoa (Chenopdium quinoa, Willd) is a good source of thiamin (0·4mg100 g), folic acid (78·1 mg100 g) and vitamin C (16·4 mg100g) as mentioned in this paper.
Abstract: The seed of an important food crop, indigenous to the Andean region of Latin America, called quinoa (Chenopdium quinoa, Willd) is a good source of thiamin (0·4mg100 g), folic acid (78·1 mg100 g), and vitamin C (16·4 mg100 g). The seeds contain twice as much γ-tocopherol (5·3 mg100 g) as α-tocopherol (2·6 mg100 g) and larger amounts of calcium (874 mg/kg), phosphorus (5·3 g/kg), magnesium (2·6 mg100 g), iron (81 mg/kg), zinc (36 mg/kg), potassium (12 g/kg), and copper (10 mg/kg) than most of the common cereal grains. The amounts of mercury, lead, and cadmium found in these samples were low in relation to the values of tolerable intake for these elements. All values are expressed on a dry-weight basis. The fat content of raw quinoa seeds was 9·7% on a dry-weight basis with high amounts of oleic acid (24·8%) and linoleic acid (52·3%). The level of linolenic acid was 3·9%. The process of removing saponins from the seeds reduces the vitamin and mineral contents to some extent. The loss is significant (p < 0·001) in the case of potassium, and considerable also in the case of iron and manganese (p < 0·01).
149 citations
TL;DR: The possibility of producing a vegetable milk for local use or an extracted protein with functional properties for use in food processing applications was studied in this article, where bambara groundnut is an underutilized African legume which provides security for many farmers as it shows considerable drought resistance.
Abstract: Bambara groundnut is an underutilized African legume which provides security for many farmers as it shows considerable drought resistance. The possibility of producing a vegetable milk for local use or an extracted protein with functional properties for use in food processing applications was studied. Milks were made by soaking bambara groundnut overnight, homogenizing and removing insoluble material to give a milky liquid. The beany taste could be removed by dry-frying the beans after soaking but before homogenization. Milks produced in this way were preferred by the taste panel (composed largely of Africans). A comparison of bambara groundnut milk and milks prepared from cowpea, pigeonpea and soybean was made using sensory and instrumental analysis. Sensory analysis showed all milks were acceptable with bambara groundnut ranked first in the preference trial. The lighter colour of bambara groundnut milk was more acceptable to the taste panel but there was no correlation between viscosity measured on a viscometer and viscosity perceived by the taste panel. A crude protein isolate (76% protein) from bambara groundnut was subjected to standard protein functionality tests but it was inferior to the standard used (egg albumen and soy isolate). It did not show any useful properties in emulsification, foam stabilization, or gelation or in a model cake system.
142 citations
TL;DR: In this article, the proximate composition and functional properties of raw, germinated, fermented and heat-treated cowpea flour were studied and the functional properties investigated were protein solubility, water and fat absorption, bulk density, foam capacity and stability.
Abstract: The proximate composition and functional properties of raw, germinated, fermented and heat-treated cowpea flour were studied. The functional properties investigated were protein solubility, water and fat absorption, bulk density, foam capacity and stability.
Germination increased the crude protein, iron and total phosphorus but decreased the carbohydrate, fat and total polyphenols content. Protein solubility was pH-dependent with a minimum at pH 4·0. Maximum protein solubility (0·39 mg/ml) was recorded for germinated flour which also showed excellent fat absorption properties. The water absorption capacity of the heat-treated cowpea flour was significantly higher (P < 0·05) than those of raw, germinated or fermented samples. Bulk densities of the germinated and fermented flours were reduced by 70·6% and 35·3% respectively. The foam of the raw flour was more stable than those of the processed samples. Incorporation of NaCl up to 0·2 m improved the foam capacity of the raw and processed flours.
Calculated on a crude protein basis, raw cowpea flour showed comparatively better water and fat absorption properties than raw winged bean or soyflour and hence it may find useful applications in fabricated foods such as bakery products and ground meat formulations.
128 citations
TL;DR: Theobroma cacao is the first plant described to date whose seeds contain a vicilin-like globulin, but apparently no legumin-class globulin.
Abstract: Differential extractions of proteins from Theobroma cacao seeds have revealed the presence of an albumin fraction and a globulin fraction with proportions of 52% and 43%, respectively, of total seed proteins. In contrast to some earlier reports, we could not detect any prolamin. The ‘glutelin fraction’ described in the literature was found to consist of residual globulin. After fermentation, the first step in cocoa processing, the proportion of the globulin fraction is considerably reduced. The major albumin is a polypeptide with an apparent molecular weight of 19 kDa. The globulin fraction contained polypeptides with apparent molecular sizes of 47 kDa, 31 kDa, and 14·5 kDa. Globulin prepared in the absence of the aspartyl protease inhibitor pepstatin contained two additional polypeptides with apparent molecular sizes of 28 kDa and 16 kDa, respectively. The negative globulin of Theobroma cacao is a glycoprotein with a sedimentation coefficient of 7–8S and a molecular weight of 150 kDa. Its subunits are not cross-linked by disulphide bridges—in contrast to the legumin-like storage globulins which are predominant in the seeds of all other dicotyledons studied so far. Therefore, Theobroma cacao is the first plant described to date whose seeds contain a vicilin-like globulin, but apparently no legumin-class globulin.
108 citations
TL;DR: It is indicated that lipolysis plays a role in the ripening of Spanish dry-cured ham and Neutral and basic lipases are more active at the beginning of the process, while lysosomal acidlipases are active through the entire process.
Abstract: Muscle lipases and esterases were assayed for activity at different stages (0–15 months) in the processing of dry-cured hams. The evolution of volatile and nonvolatile free fatty acids, during processing, was also determined. All the assayed enzymes were found to be quite stable and active even after 15 months of processing. Most lipolysis seemed to occur during the first 5 months when maximal generation of free fatty acids was detected. Neutral and basic lipases are more active at the beginning of the process, while lysosomal acid lipases are active through the entire process. These enzymes seem to be the main ones responsible for the observed lipolysis. Muscle esterases showed excellent stability, but the amounts of volatile free fatty acids were very low, suggesting only a minor role for these enzymes. The study indicates that lipolysis plays a role in the ripening of Spanish dry-cured ham.
TL;DR: Saponin-A remaining in the seeds decreased to 0·31% of the dry weight, and saponin-B was completely removed by this process, and neither protease inhibitor nor tannins were detected in the quinoa seeds.
Abstract: The seeds of quinoa (Chenopodium quinoa, Willd), a food crop of the Andean region of Latin America, contain protein of good quality and high amounts of carbohydrates, fat, vitamins, and minerals. An industrial process for manufacturing infant food using quinoa as a basic raw material is being developed. The presence of antinutrients are of importance in this context, and this paper deals with saponins, phytic acid, tannins and protease inhibitors in quinoa seeds. The samples of quinoa analysed in this experiment contained two main types of saponins. The amount of saponin A (β- d -glucopyranosyl -[β- d -glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl -(1 → 3)]-3-β-23- dihydroxy -12- en -28- oate methyl ester ) was 0·7% of the dry weight and that of the saponin B (β- d -glucopyranosyl -[β- d -glucopyranosyl -(1 → 3)-α- l -arabino- pyranosyl -(1 → 3)]-3-β-23- dihydroxyolcan -12- en -28- oate was 0·2% of the dry weight. These were the major saponins found in the quinoa bran collected while polishing the seeds. After scrubbing and washing, the level of saponin-A remaining in the seeds decreased to 0·31% of the dry weight, and saponin-B was completely removed by this process. The content of phytic acid in the quinoa seeds was about 1% of the dry matter, and scrubbing and washing reduced the phytic acid content of the seeds by about 30%. Neither protease inhibitor nor tannins were detected in the quinoa seeds.
TL;DR: In this paper, the authors investigated six of the most commonly used honeys and their chemical characteristics were reported and compared with the Saudi Standards on honey, and Microscopic examination confirmed the origin of the honey claimed by the manufacturer.
Abstract: Floral identification of six of the most commonly used honeys was investigated and their chemical characteristics were reported and compared with the Saudi Standards on honey. Microscopic examination confirmed the origin of the honey claimed by the manufacturer. ‘Sugar-feed’ honey was significantly (P
TL;DR: In this paper, the thermal and mechanical properties of concentrated (25-35% w/w) starch gels of 43 nonwaxy rices, varying in their amylose content and gelatinization characteristics, were investigated by small amplitude oscillatory shear measurements and differential scanning calorimetry.
Abstract: The thermal and mechanical properties of concentrated (25–35% w/w) starch gels of 43 non-waxy rices, varying in their amylose content and gelatinization characteristics, were investigated by small amplitude oscillatory shear measurements and differential scanning calorimetry. The storage modulus (G') of freshly prepared gels increased exponentially with increasing amylose content. An inverse linear relationship was also found between tan δ and amylose content (r = −0.75, p 29%) rice starch gels exhibited tan δ values less than 0.1, indicating well cross-linked networks. At starch concentrations within 10–25% (w/w), the dependence of storage modulus on concentration followed power law relationships; G' varies as C2.2–2.9 (r>0.96, p<0.01). Changes in gel rigidity (G') upon storage were not solely dependent on amylose content. Kinetic experiments on staling of gels (35% w/w, 8°C) by calorimetry indicated that granular lipids retarded this process; the effect was more pronounced for low-amylose rice starches.
TL;DR: In this paper, commercial mineral waters packed in polyethylene-lined aluminium/cardboard packages were incubated at 40°C and sensorially evaluated for intensities of descriptors: synthetic, musty, sickly, metallic, astringent and dry.
Abstract: Commercial mineral waters packed in polyethylene-lined aluminium/cardboard packages were incubated at 40°C and sensorially evaluated for intensities of the descriptors: synthetic, musty, sickly, metallic, astringent and dry. Tasting of these samples with the use of nose clips diminishes the intensities of the descriptors significantly, except for dry. Volatile compounds of this mineral water were analysed by sniffing the effluent of a gas chromatographic column, which provided similar descriptors as above. The components detected by sniffing were tentatively identified by combined gas chromatography and mass spectrometry as being mainly aromatic hydrocarbons and carbonyls. Semiquantitative analysis showed that the concentrations of the compounds which migrated into the mineral water ranged between 10 and 15 ppb. Storage at elevated temperatures seems to involve flavour deterioration, because no taint was observed in mineral water samples, which were incubated at 20°C.
TL;DR: In this paper, different methods of sampling the volatiles in the mouth during eating have been investigated, using extra strong mints as a simple food system, which contains high levels of volaticles and a simple aroma profile.
Abstract: Using extra strong mints as a simple food system, which contains high levels of volatiles and a simple aroma profile, different methods of sampling the volatiles in the mouth during eating have been investigated. Release of volatiles in the mouth is important in determining the profile perceived by the receptors in the nose and thus relates directly to our perception of aroma when food is eaten. Direct introduction of volatiles from the mouth and nose into a mass spectrometer did not provide information on the volatile profile, as the air introduced greatly reduced the sensitivity of the machine, and volatiles could not be reliably detected above the background noise. Cryogenic trapping on fused silica capillaries followed by gas chromatography and mass spectrometry did give profiles which were different for headspace, mouthspace and nosespace. Problems with loss of volatiles after trapping and the presence of water on the traps limited the usefulness of this method. Trapping on Tenax traps overcame some of these problems, and similar profiles to those obtained with cryogenic trapping were obtained. The amounts of two major volatiles in the headspace and nosespace were estimated and found to be menthone (8·32 and 24·3 mg m 3 air) and menthol (2·59 and 4·3 mg m 3 air), respectively. The concentrations of menthone in both headspace and nosespace were below the reported odour threshold value, but menthol was present in concentrations above the odour threshold. The method shows that volatile profiles during eating can be measured, but further development is required to improve sensitivity if the technique is to be applied to other foods.
TL;DR: The soaking of legume seeds in tap water or sodium bicarbonate solution resulted in a decreased concentration of sucrose and the raffinose family of sugars in each case, but the extent of losses was enhanced as the time of soaking was increased and the removal of oligosaccharides was higher in alkaline medium than in water.
Abstract: Raffinose family oligosaccharides (raffinose, stachyose and verbascose) present in legume seeds have been reported to cause flatulence. The object of this work was to study the effect of methods of domestic processing, including soaking in tap water and 0.5% sodium bicarbonate solution, cooking and autoclaving of unsoaked and soaked seeds, on oligosaccharide contents of four commonly consumed legumes in Egypt, namely: faba bean (Vicia faba L.), lentil (Lens culinaris), common bean (Phaseolus vulgaris) and cowpea (Vigna sinensis). The identification and quantitative determination of oligosaccharides using gas-liquid chromatography (GLC) indicated that the four raw legume seeds contained sucrose, raffinose, stachyose and verbascose. The raffinose family oligosaccharides account for 67.3, 63.2, 53.0 and 51.0% of the total soluble sugars in cowpea, faba bean, lentil and common bean, respectively. The major oligosaccharide was verbascose in faba bean and stachyose in the other three legumes. The soaking of legume seeds in tap water or sodium bicarbonate solution resulted in a decreased concentration of sucrose and the raffinose family of sugars in each case. The extent of losses was enhanced as the time of soaking was increased. The removal of oligosaccharides from legume seeds was higher in alkaline medium than in water. In addition, the loss of an individual sugar was not related to its solubility or molecular weight. Cooking of unsoaked seeds led to a large decrease in oligosaccharide content of all studied legumes compared with soaking for 12 h. The loss in the raffinose family oligosaccharides after cooking of soaked seeds was highest in common bean and lowest in faba bean. Autoclaving had a greater effect on removal of oligosaccharides than did cooking. In all cases, autoclaving of soaked seeds resulted in complete disappearance of raffinose.
TL;DR: The yield of crude mucilage (CM) obtained from yellow mustard ( Sinapis alba, L.) was 5% of the total seed weight as mentioned in this paper, which revealed carbohydrates as the major component with ash (1·7-15·0%) and protein (2·2-4·4%) as minor constituents.
Abstract: The yield of crude mucilage (CM) obtained from yellow mustard ( Sinapis alba , L.) was 5% of the total seed weight. CM was separated into a water-soluble fraction (WS, 55·6%) and a water-insoluble fraction (WI, 38·8%). Proximate analysis of CM and its fractions revealed carbohydrates as the major component (80–94%) with ash (1·7–15·0%) and protein (2·2–4·4%) as minor constituents. Glucose (22–35%) was the major monosaccharide present followed by galactose (11–15%), mannose (6·0–6·4%), rhamnose (1·6–4·0%), arabinose (2·8–3·2%) and xylose (1·8–2·0%). All mucilage fractions exhibited interfacial activity and shear thinning behaviour typical of xanthan gum dispersions. Of the mucilage fractions studied, the WS fraction was least affected by pH, temperature and solutes (NaCl, sucrose).
TL;DR: In this article, the authors conducted a study on the growth and cultivation of Pleurotus tuber-regium on local cellulosic wastes and found that the sclerotia grown on banana leaves were the richest in protein, lipid, ethanol-soluble sugar, crude fibre, calcium and magnesium contents.
Abstract: Studies were conducted on the growth and cultivation of Pleurotus tuber-regium on local cellulosic wastes. Andropogon tectorum straw supported the greatest mycelial growth, and cotton and oil palm pericarp wastes supported the least. For cultivation of edible sclerotia, cotton waste and rice straw gave the highest yield and banana leaves gave the lowest. However, with regard to protein, lipid, ethanol-soluble sugar, crude fibre, calcium and magnesium contents, the sclerotia grown on banana leaves were the richest. In contrast, the sclerotia cultivated on corn cob were the poorest in sodium, potassium, calcium, magnesium and phosphorus contents. In all the sclerotia cultivated on banana leaves, corn cob, cotton waste and rice straw, protein and potassium were the most abundant nutrients. These results are discussed in relation to the prospect of cultivating P. tuber-regium in Nigeria.
TL;DR: In this paper, seven whole-grain cereals were examined to determine extrusion processing effects on in-vitro protein digestibility, and the most digestible products were produced at extrusion combination: 15% feed moisture, 100°C/150°C product temperature and 100 rpm.
Abstract: Seven whole-grain cereals were examined to determine extrusion processing effects on in-vitro protein digestibility. Eight extrusion conditions were applied and effects of cereal variety, extrusion temperature, RPM and feed moisture on in-vitro protein digestibility were studied. Protein digestive acceptability of unprocessed and extruded cereals was determined using an in-vitro method of enzymatic hydrolysis. The most protein-digestible products were produced at extrusion combination: 15% feed moisture, 100°C/150°C product temperature and 100 rpm. This effect was significant when considered across all cereals. Results of this study suggest that a particular combination of extrusion process conditions may be applied when extruding a wide variety of cereals, with the benefit of improving protein digestibility.
TL;DR: In this paper, full-fat flours processed from seeds of African yam bean (AYB) were evaluated for their functional properties and found that the foam and emulsion capacities were greatest between NaCl concentrations of 0·2 and 0·4 m.
Abstract: Full-fat flours processed from seeds of African yam bean (AYB) were evaluated for their functional properties. Foam and emulsion capacities were greatest between NaCl concentrations of 0·2 and 0·4 m . Steeping increased the emulsion capacity of AYB flour over roasting and malting. Roasting at 120°C reduced emulsion capacity, foam capacity and stability. However, it increased the oil and water absorption capacities relative to other processes.
TL;DR: There was a significant reduction in protein nitrogen and true protein contents of three cereal grains at 75% infestation level but the decrease was non-significant at the 25 and 50% levels of grain infestation as compared to control (uninfested grains).
Abstract: A significant increase was recorded in the levels of total nitrogen, total protein, non-protein nitrogen and uric acid contents of wheat, maize and sorghum grains having 25, 50 and 75% infestation caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius separately and in mixed population. On the other hand, there was a significant reduction in protein nitrogen and true protein contents of three cereal grains at 75% infestation level but the decrease was non-significant at the 25 and 50% levels of grain infestation as compared to control (uninfested grains). Both insect species produced uric acid contents above acceptable limits (10 mg/100 g) even at 50% infestation levels in three cereal grains. Variations in contents of nitrogenous compounds during storage (1, 2 and 4 months) were marginal.
TL;DR: In this article, the reaction mechanism of the synthesis of 2-amino-3,4-dimethylimidazo(4,5-f)-quinoline and 2-amide-3.4,8-trimethylimideamines, amino-imidazoazarenes, was studied.
Abstract: The reaction mechanism of the synthesis of 2-amino-3,4-dimethylimidazo(4,5-f)-quinoline and 2-amino-3,4,8-trimethylimidazo(4,5-f)quinoxaline as compounds of the new class of mutagenic heterocyclic amines, amino-imidazoazarenes, in the reaction between aldoses, amino acids and creatinine, has been studied. The reaction involves two reaction steps: (a) the initial step and (b) the steady-state reaction step. The initial step depends on the existence and kinetics of the Maillard and Strecker reactions and pyridine and pyrazine free radical formations. Stabilization of the formed free radicals occurs in the steady-state step, giving pyridine and pyrazine derivatives. These compounds reacted with creatinine and formed amino-imidazoazarenes. The proposed reaction mechanism of the formation of the amino-imidazoazarenes has been studied by Electron Spin Resonance (ESR), 1 H Nuclear Magnetic Resonance ( 1 H NMR) spectroscopy and Mass spectrometry (MS).
TL;DR: In this article, the effects of cooking on the fatty acid concentrations and the stability of long chain n-3 fatty acids in fish flesh were studied and the cooking methods used were boiling, baking in the normal and microwave oven and frying with sunflower and rapeseed oils.
Abstract: The effects of cooking on the fatty acid concentrations and the stability of long chain n-3 fatty acids in fish flesh were studied. The cooking methods used were boiling, baking in the normal and microwave oven and frying with sunflower and rapeseed oils. Three freshwater fish species (rainbow trout, vendace and pike) with different sizes and lipid contents were studied. The concentrations of long chain n-3 fatty acids in fish flesh increased in most cases due to the cooking process. This was mostly caused by the loss of moisture. However, in baked and microwave-cooked vendace their concentrations increased about 70% even when calculated on a dry weight basis. Frying oils were efficiently absorbed into lean vendace and pike, and to some extent into medium fatty rainbow trout. The absorption of n-6 fatty acids from cooking oils may interfere with the biological effects of n-3 fatty acids.
TL;DR: The antinutritive factors and nutritive value of rapeseed products were evaluated in this paper, and the results showed that the elimination of proteins eliminated 72-95% of glucosinolates, 74-92% of phytic acid and 100% of tannic acid for protein concentrate and isolate.
Abstract: The antinutritive factors and nutritive value of rapeseed products were evaluated. The reductions in antinutritional factors by heat processing ranged from 47 to 94% for glucosinolates, from 9 to 43% for phytic acid and from 41 to 67% for tannic acid after toasting and autoclaving treatments. Isolation of proteins eliminated 72–95% of glucosinolates, 74–92% of phytic acid and 100% of tannic acid for protein concentrate and isolate. All processes destroyed trypsin inhibitor activity completely. Rapeseed products have a balanced amino acid composition and their proteins are relatively high in sulphur-containing amino acids and lysine. The chemical score and limiting amino acids of rapeseed products varied considerably, depending on the type of process. Heat treatment and isolation of proteins improved the in-vitro digestibility of rapeseed proteins. The essential amino acid index of rapeseed products ranged from 66 to 81%. Rapeseed meal has high levels of riboflavin, niacin and pyridoxine. Riboflavin and niacin are more stable to the heat process than thiamine, pyridoxine and pantothenic acid. Many of these vitamins are lost during isolation of proteins. The meals are rich in Ca, K, P and Mg. Some minerals increased and others decreased during the processing.
TL;DR: In this paper, the physicochemical properties and proximate composition of two vegetable and field pea varieties were investigated for physicochemical characteristics and proximities, and the results showed that the vegetable pea variety Arkel had higher hydration capacity, hydration index, swelling capacity and swelling index than the field peas.
Abstract: Two each of the vegetable and field pea varieties were investigated for physicochemical properties and proximate composition. Density ranged from 1·27 to 1·30 g/ml in different pea cultivars. The vegetable pea variety Arkel had higher hydration capacity, hydration index, swelling capacity and swelling index than the field pea cultivars. Varietal differences in field peas had no influence on the physicochemical properties. Field pea varieties contained higher amounts of total carbohydrates and lower amounts of ash, fat and crude fibre than vegetable peas. Bonneville, Arkel and Rachna varieties had similar crude protein values.
TL;DR: In this article, both dialysis and precipitation techniques were carried out to determine SDF in fruits, legumes and cereals, and the results showed the incomplete determination of SDF with the present analytical methods.
Abstract: The ethanol precipitation of soluble dietary fibre (SDF) constituents is a common step among modern analytical methods. This precipitation may involve two possible error sources: non-fibre component co-precipitation and incomplete precipitation of SDF components such as pectins. Both possibilities are studied in the present work. Citrus pectins and pectin-organic acid (citric and oxalic) mixtures were dissolved in phosphate buffer and precipitated in 78% ethanol at different pH values. Incomplete recovery of pectins (84–89%, depending upon the pH of the solution) and significant co-precipitation of organic acids were observed. Dialysis has been studied as an alternative method for obtaining SDF. Both dialysis and precipitation techniques were carried out to determine SDF in fruits, legumes and cereals. The SDF values (neutral sugars plus uronic acids) obtained by dialysis were higher in all the samples than the values obtained by precipitation. These results show the incomplete determination of SDF with the present analytical methods. In addition, gravimetric methods can include a fraction of non-fibre constituents, such as organic acids, as fibre.
TL;DR: In this article, the fat content and fatty acid composition of hazelnut samples corresponding to four different varieties, all cultivated in two different areas of Catalonia (Spain) during three consecutive years, were analyzed.
Abstract: In a former paper (Parcerisa et al. (1993). Food Chem., 48, 411–14), the fat content and fatty acid composition of hazelnut samples corresponding to four different varieties, all cultivated in two different areas of Catalonia (Spain) during three consecutive years, were analysed. Those results showed that the fatty acid composition was influenced by the geographical origin and harvesting year of samples. In the present paper, results of triglyceride composition corresponding to the same varieties and harvesting years are presented using HPLC. Twelve different triglycerides have been identified. Main proportions correspond to triolein ( X = 46·9% ) and linoleodiolein ( X = 18·4% ). Triglyceride composition of samples changed significantly as a function of harvest and geographical origin but not in relation to the hazelnut variety, in agreement with previous results. It is thus established that these factors have a great influence on the characteristics and quality of nuts. In addition, a correlation study with previous fatty acid composition data was carried out, in order to check some aspects related to the biosynthesis of glycerides in these nuts. OOO, POO and LOO are always correlated with all glyceride and fatty acid contents, except with PLP and palmitic acid.
TL;DR: In this paper, a reversed-phase liquid chromatographic assay which utilizes isocratic elution and detection by two detectors has been developed to measure simultaneously several carotenoids, retinol, retinyl esters, and α- and γ-tocopherols in serum.
Abstract: A sensitive high-performance reversed-phase liquid chromatographic assay which utilizes isocratic elution and detection by two detectors has been developed to measure simultaneously several carotenoids, retinol, retinyl esters, and α- and γ-tocopherols in serum. Although 100 μl of serum or plasma is used routinely, as little as 10 μl can be analyzed. Typical lower limits of detection (5 : 1 signal/noise ratio) are 0.2 pmol for retinol, 6 pmol for α-tocopherol, 1 pmol for β-carotene, and 2 pmol for retinyl palmitate. Although lutein and zeaxanthin were only partially resolved from each other, all other major serum carotenoids including α-carotene from β-carotene and α-cryptoxanthin from β-cryptoxanthin were completely separated. Retinyl hexanoate and β-apo-8'-carotenyl decanoate are convenient, readily prepared internal standards for this assay. Relative retention indices, based on elution times of alkylphenone standards, proved useful both for characterization of compounds and for comparison between columns.
TL;DR: In this article, the authors found significant varietal differences in the starch digestibility and contents of reducing sugars, non-reducing sugars, and starch in four cultivars of field as well as vegetable peas.
Abstract: There were significant (P < 0·05) varietal differences in the starch digestibility (in vitro) and contents of reducing sugars, non-reducing sugars, and starch in four cultivars of field as well as vegetable peas. Various domestic processing and cooking methods, including soaking for 6, 12 and 18 h, soaking (12 h) followed by dehulling, ordinary and pressure cooking of unsoaked, soaked and soaked-dehulled seeds, and sprouting for varying periods, i.e. 12, 24 and 48 h, brought about significant increase in starch digestibility of peas. Pressure cooking was found to be the most effective method followed by ordinary cooking, sprouting, dehulling and soaking. Cooking may gelatinise starch and sprouting may mobilise starch, thereby resulting in improved starch digestibility by pancreatic amylase.