Quality control method based on quartz crystal microbalance and WGA for flour milled from germinated wheat

Plasma membrane is the initial sensor of different stress conditions and its composition is modified with response to environmental changes. In the present study, we have modified the lipid composition of the membrane by growing Saccharomyces cerevisiae in the presence of different fatty acids and ergosterol. All supplemented fatty acids were incorporated into the cell and this incorporation produced significant changes in the lipid composition. The incubation with ergosterol also modified the lipid composition of the cells; however, these cells presented a strong reduction in the content of this sterol. The different cellular lipid composition has been related to viability and fermentation performance at low temperature (13 °C). The cells incubated with palmitoleic acid (C16:1) showed higher viability and significant reduction in the fermentation length. These cells presented higher C16:1 and ergosterol content, shorter chain length of the fatty acids and higher ratio of sterols/phospholipids. Therefore redesigning the composition of cellular membranes during industrial yeast propagation seems to be a promising strategy for improving fermentation performance in the winery.     

Changes in the Lipid Composition of Saccharomyces cerevisiae Race Capensis (G-1) During Alcoholic Fermentation and Flor Film Formation

The cellular lipid composition of one flor-forming strain of Saccharomyces cerevisiae during fermentation and the subsequent period of film formation with different oxygen levels was studied. Irrespective of fermentation conditions, only those yeasts which came into contact with oxygen after fermentation formed a flor film. After the fermentation, these yeasts entered an adaptation phase in which the percentage of oleic acid increased considerably at the expense of other long-chain fatty acids. Their phospholipid contents remained high, as well as the unsaturation index of their fatty acids and the ergosterol/phospholipids ratio was maintained below 1. These changes allowed an increased viability of yeasts in the wine of up to 80% and the acquisition of sufficient hydrophobicity and floatability to reach the surface and form flor film.     

Species‐specific differences in the fatty acid profiles of the lipids of the yolk and of the liver of the chick

Differences between four avian species of commercial importance (chicken, turkey, duck and goose), in terms of the relationship between the dietary fatty acids supplied in the diet of the layers and the fatty acid composition of the egg yolk lipids, were investigated. Laying hens of the four species were provided with diets with very similar fatty acid compositions. The polyunsaturated fatty acid content of the diets consisted of linoleic and α‐linolenic acids at approximately 50% and 6% (w/w of total fatty acids), respectively, for all four species. In spite of the very similar dietary provision of fatty acids, the subsequent fatty acid profiles of the yolk lipids differed markedly between the four species. In particular, the proportion of docosahexaenoic acid in the total lipid of the yolk was three to five times greater for the chicken compared to the other three species. By contrast, the proportion of arachidonic acid in total yolk lipid was approximately two times greater for the goose and duck than for the chicken and turkey. Thus the chicken was more efficient at incorporating long‐chain (C₂₂ ) fatty acid of the n‐3 series into yolk lipid whereas the duck and goose preferentially incorporated C₂₀ fatty acid of the n‐6 series. The turkey eggs contained a similar proportion of arachidonic acid but less docosahexaenoic acid than the chicken eggs. The main differences between the avian species in terms of the yolk levels of C_{20 –22} polyunsaturated fatty acids were in the phospholipid fraction since only low levels of these fatty acids were present in the triacylglycerol fraction. The relative proportions of docosahexaenoic acid in the phospholipid and triacylglycerol fractions of the livers of the newly‐hatched chicks of the four species reflected the differences displayed by the yolks. The proportions of arachidonic acid in these liver lipid fractions, however, did not reflect the species differences in yolk lipid composition. © 1999 Society of Chemical Industry     

Characteristics of lipids in buckwheat grain and isolated starch and their changes after hydrothermal processing

Studies were carried out on bond and free lipids of buckwheat grain and isolated starch. As regards free and bond lipids, fraction composition (percentages of neutral and polar fraction) and fatty acids were determined. It was found that the content of free lipids in buckwheat grain was twice higher than of bond lipids. On the other hand, in case of starch percentage of free lipids was twice lower than of bond lipids. As regards free and bond lipids of buckwheat grain and starch, main fraction was represented by the neutral one. Percentages of glycolipids and phospholipids amounted to only from 5 to 7%. Fatty acids were predominated by unsaturated acids C_18:2 and C_18:1. Fire and steam hydrothermal processing resulted in several quantitative changes, the most important ones being an increase of free lipid content in the grain and of bond lipid content in the starch, changes in the percentage of glycolipids and phospholipids, an increase of saturation of free lipid fatty acids in the grain, and of saturation of bond lipid fatty acids in the starch.     

Changes in lipid components during the development of the french bean seed (Phaseolus vulgaris)

Changes in lipid classes, fatty acid composition and distribution have been monitored during the germination, development and maturation of the French bean seed Phaseolus vulgaris. A lipase activity profile over time was also determined. Ungerminated seeds contained high levels of triglycerides and free fatty acids, but low levels of polar lipids, monoglycerides, and diglycerides. Five days after germination there was a decrease in the quantity of triglycerides and free fatty acids and a concomitant increase in the levels of monoglycerides, diglycerides, and polar lipids. As development and maturation progressed, triglycerides increased substantially at the expense of mono- and diglycerides. Ungerminated seeds contained high levels of C₂₀-C₂₂ fatty acids which decreased after germination with a concomitant increase in C₁₆-C₁₈ unsaturated fatty acids. A study of the fatty acid distribution among the different classes of lipids demonstrated that 55% of the unsaturated fatty acids in the ungerminated seeds were present in the triglycerides, whereas the remainder were distributed among the mono- and diglycerides as well the other lipid classes (free fatty acids, polar lipid, and sterols). Five days after germination, the majority of these unsaturated fatty acids were found in the glyceride form. Overall the lipid classes, fatty acid composition and distribution changes during development and maturation of the French bean seed indicated that it shares many of the characteristics of soya bean development.     

Composition of adipose tissue triglycerides of neonatal and year-old lambs

Triglyccrides were isolated from perinephric (internal) and subcutaneous (external) adipose tissue obtained from neonatal lambs and from lambs which had been fed, until they were a year old, on a semi-synthetic ration or on a diet of grass cubes. the triglycerides went analysed for their fatty acid composition (including trans unsaturated acids) and for the intramolecular distribution of these acids between the primary and secondary alcoholic groups of the glycerol moiety. Whereas in the year-old lambs (and in adult sheep previously examined), the triglycerides of internal adipose tissue had a higher content of stearic acid and trans unsaturated acid than those of external tissues, the triglycerides from the perinephric and subcutaneous tissues of the neonatal lambs were very similar in fatty acid composition. Palmitic acid and C₁₈ mono-unsaturated acid together constituted more than 80% of the total acids. This composition resembles that of the subcutaneous triglycerides of the grown animal and suggests that, at all stages of growth, the triglycerides of external tissues are largely the result of endogenous synthesis. The fatty acids of the adipose tissues of the neonatal animals did not contain any of the acids of exogenous origin, such as those with trans double bonds, which characterise the triglycerides of the growing and mature animals, particularly those of the internal depots. Nevertheless, the intramolecular disposition of the fatty acids in the triglycerides formed in utero was similar to that previously observed in triglycerides from both the internal and external depots of the adult sheep. Saturated acids (palmitic and stearic acids) predominated amongst those esterified in the 1-and 3-positions of the glycerol moiety and unsaturated acids (almost entirely oleic acid) were the major components esterified in the 2-position. While the triglycerides from corresponding body sites in the two groups of year-old lambs were generally quite similar with respect to their content of palmitic acid, stearic acid and C₁₈ mono-unsaturated acid, the contribution of trans isomer to the total C₁₈ mono-unsaturated acid was considerably greater in the tissues (particularly perinephric tissue) of the animals fed on grass cube than in the tissues of those given the semi-synthetic ration. This difference between the two groups of lambs was associated with a corresponding difference in the proportions of C₁₈ trans unsaturated acid in the lipids of the rumen contents of the animals.     

TUDIES ON THE FATTY ACID COMPOSITION OF HOP EXTRACT

Studies on fatty acids composition of hop extract obtained from Vurtenberg hop by extraction with a threecomponent mixture was carried out. It has been established that the content of fatty acids in hop extract is 0.3% ±5%. Fatty acids composition was determined by Gas-chromatographic analysis. The presence of the following unsaturated fatty acids has been proven: C_16:1; C_18:1; C_18:2; C_18:3; C_20:1 which represent about 40% of the general content of fatty acids in the extract.     

Generation of glycerophospholipid molecular species in the yeast Saccharomyces cerevisiae. Fatty acid pattern of phospholipid classes and selective acyl turnover at sn-1 and sn-2 positions

Acyl chains linked to phospholipids of the yeast, Saccharomyces cerevisiae, are mainly C16:1 and C18:1 accompanied by minor amounts of C14:0, C16:0 and C18:0. In view of this rather simple fatty acid composition, the question arose whether in yeast, as in higher eukaryotes, fatty acyl groups were characteristically distributed among the sn-1 and sn-2 positions of distinct phospholipid classes. Analysis of fatty acids linked to the sn-1 and sn-2 positions of the major phospholipids showed that indeed saturated fatty acyl groups predominated in the sn-1 positions. While the percentage of saturated fatty acids was low (10%) in phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) from cells grown on rich medium, it was higher in phosphatidylserine (PtdSer) (25%) and highest in phosphatidylinositol (PtdIns) (41%). Oleate was mainly linked to position sn-2, while palmitoleate predominated in position sn-1. Striking differences in the fatty acid distribution of phospholipids that are metabolically closely related (e.g. PtdSer and PtdEtn, PtdEtn and PtdCho, and PtdIns and PtdSer) suggest that pathways must exist for the generation of distinct phospholipid molecular species within the different phospholipid classes. The highly selective incorporation of exogenous [¹⁴C]palmitic acid (90%) and [³H]oleic acid (99%) into the sn-2 position of PtdCho, and the preferential incorporation of these fatty acids into the sn-2 position of PtdEtn (70 and 90%, respectively, for palmitic and oleic acid) are compatible with the postulate that phospholipase A₂-mediated deacylation followed by reacylation of the lysophospholipids is involved in the generation of phospholipid species in yeast.     

The fatty acid and phospholipid composition of longissimus dorsi muscle from Pietrain and Large White pigs

An examination was made of the fatty acid and phospholipid composition of longissimus dorsi muscle from Pietrain and Large White pigs. The neutral lipid fraction from Pietrain muscle had a more unsaturated fatty acid composition possibly because of a reduced rate of intramuscular fat deposition in these pigs. The phospholipid content of muscle and muscle sarcoplasmic reticulum was similar in both breeds. The fatty acid composition of phospholipid and the concentrations of individual phospholipids were also similar. Differences in the lipid composition of muscle between the breeds appear to reflect a reduced capacity for carcass fat deposition in Pietrains rather than the propensity of pigs of this breed to produce muscle which is pale, soft and exudative (p.s.e.).     

The fatty acid composition of the lipids of earthworms.

Lipids were freshly extracted from earthworms from agricultural pasture land, and fatty acid compositiona analyses were carried out on the total lipids; phospholipids; triglycerides; free fatty acids; mixed sterol esters, wax esters, free methyl esters, etc.; glycolipids; and neutrallipids. A wide variety of fatty acids ranging from C₁₀ to C₃₂ were identified. In the fatty acids of the total lipids, polyunsaturated constituents predominated in amount, while monomethyl branched, isoprenoid and n-odd-numbered acids were present in appreciable proportions. Eicosa-5,8,11,14,17-pentaenoic acid and arachidonic acid occurred at higher levels than any other components and were located mostly in the phospholipids. Significant contents of linoleic and linolenic acids were also detected. Earthworms collected in spring had a fatty acid composition which differed noticeably from that of worms from other seasons. The content of lauric acid during spring was much higher than that normally found in animals or pasture plants. The composition of the free fatty acids indicated that these components were the products of lipolysis and were derived from all the lipid classes. The results of this investigation suggest that the diet of local earthworms, which is reported to consist mainly of dead plant material, is supplemented by living and dead microorganisms from ingested soil.     

Ethanol tolerance of five non-Saccharomyces wine yeasts in comparison with a strain of Saccharomyces cerevisiae—influence of different culture conditions

The kinetics of cell inactivation at high concentrations of ethanol (22.5% and 25% v v⁻¹) was studied with particular reference to the influence of different cultivation conditions (aerobiosis, semi-aerobiosis, anaerobiosis, addition of survival factors) prior to ethanol challenge. The levels of fatty acids and sterols in cells grown under these different conditions were analysed in order to derive a potential relationship between the ethanol tolerance and the lipid composition of the different strains studied. Under the conditions tested, Hanseniaspora guilliermondii showed an ethanol tolerance very similar to that of Saccharomyces cerevisiae, and very different to that of the other apiculate yeast, H. uvarum. The survival of S. cerevisiae and H. guilliermondii at 25% (v v⁻¹) ethanol was strongly influenced by the conditions of cultivation prior to the ethanol challenge. A small increase in survival was observed for H. uvarum and Torulaspora delbrueckii in the cultures grown in aerobiosis. Growth of these yeasts in anaerobiosis in the presence of added ergosterol and Tween 80 (as a source of oleic acid) did not induce a considerable tolerance to the ethanol challenge, in spite of the incorporation of these compounds by the cells. In these growth conditions Debaryomyces hansenii was not capable of incorporating the survival factors and did not increase the ethanol tolerance. It is shown in this work that, besides S. cerevisiae, the presence of oxygen and the addition of survival factors to the culture conditions and the subsequent increase in the proportion of cell sterols and unsaturated fatty acids may play an important role in the ethanol tolerance of some non-Saccharomyces yeasts. This effect was not, however, observed in all of the yeasts studied.     

Supercritical fluid extraction and characterization of lipids from algae scenedesmus obliquus

Supercritical carbon dioxide (SC‐CO₂) extractions (with and without ethanol as an entrainer) were carried out to remove lipids and pigments from protein concentrate of green algae (Scenedesmus obliquus) cultivated under controlled conditions. The content and fatty acid composition of algal lipids using column, thin‐layer (TLC) and gas‐liquid chromatography (GLC) were determined. Absorption spectra of extracted fractions showed the predominance of chlorophyll A (λ_max at 410nm). Single step supercritical carbon dioxide (SC‐CO₂) extraction resulted mostly in removal of neutral lipids and a part of glycolipids, but phospholipids were not extracted. Addition of ethanol to SC‐CO₂ increased the amount of glycolipids and phospholipids in the extract. TLC pattern of algal lipids showed that the main part of neutral lipids consisted of diglycerides, triglycerides, hydrocarbons, free sterols, and sterol esters. The glycolipids were mostly monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. In phospholipids, phosphatidyl choline, phosphatidyl glycerol, and phosphatidyl ethanolamine were the main compounds. Fatty acid composition patterns indicated the main fatty acids to be 16:0, 16:1, 16:2, 16:3, 16:4, 18:1, 18:2 and 18:3(a). Relatively high recovery of polyunsaturated fatty acids and essential fatty acids in supercritical fluid extracted algal lipids and protein isolates were observed.     

DISTRIBUTION OF ESTERS PRODUCED DURING SUGAR FERMENTATION BETWEEN THE YEAST CELL AND THE MEDIUM

The distribution of the esters formed during sugar fermentations between the yeast cells and the medium was investigated in fermentations by 5 strains of Saccharomyces cerevisiae and 3 strains of S. uvarum (carlsbergensis). The esters studied included the acetates of isoamyl alcohol and phenethyl alcohol and the ethyl esters of the C₆-C₁₂ fatty acids. All of both acetates appeared in the medium. The proportion of the fatty acid ethyl esters transferred to the medium decreased with increasing chain length: all in the medium for ethyl caproate, 54–68% for ethyl caprylate, 8–17% for ethyl caprate, and all remaining in the yeast cell for ethyl laurate. A higher proportion of the esters formed appeared to remain in the cells of the S. uvarum strains than in cells of S. cerevisiae.     

Evaluation of whisky distillery by-products. VI. The reduction in digestibility of malt distiller's grains by fatty acids and the interaction with calcium and other reversal agents

In vitro methods have been used to study the inhibitory effects of fat and fatty acids which reduce the digestibility of malt distiller's grains (MDG). Glycerol and individual fatty acids below C⁸ in the homologous series do not produce any measurable decrease in digestibility. Capric acid lowers digestibility appreciably and the depression is even greater with lauric acid. Myristic, palmitic and stearic acids are less active than lauric and the greatest depressions were recorded with the unsaturated acids which showed greater activity with increasing unsaturation. Calcium salts produced partial reversal of digestibility in the presence of saturated acids above C¹⁰ and substantially greater reversal with the C¹⁸ unsaturated acids. The reduction in digestibility of MDG and in steam volatile acid production in the digesta by the presence of native fat may be attributed to the high content of oleic and linoleic acids which can also account for the marked reversal of effects by calcium. Alkaline earth metals and iron were examined for reversibility but only calcium produced consistent effects. Addition of ergocalciferol produced reversal effects similar to calcium. The reversal by calcium was evident when the calcium was added to the digesta up to 8 h after the commencement of incubation which indicates that the fatty acids have a bacteriostatic effect. In in vivo digestibility trials sheep consumed increasing amounts of dried MDG when the level of calcium supplementation was increased. Rations containing fat levels similar to that of MDG should be supplemented with calcium at levels higher than normal requirements of the element.     

The fatty acid composition of the lipids from two species of hake

The fatty acid composition of lipids extracted from the livers, muscle and skin of two hake species Merluccius capensis and M. paradoxus were studied. In one instance a comparison was made between the fatty acid composition of the phospholipid and triglyceride fractions of the lipids. In pre-spawning fish there appears to be a tendency for M. capensis to have fat of higher unsaturation than M. paradoxus. The only consistent species difference found was the high level of unsaturation of skin lipids relative to muscle lipids in M. paradoxus, a species living at greater depth and lower water temperatures. The major saturated fatty acid in hake lipids is that with 16 carbon atoms, the major monoenoic acid the one with 18 carbon atoms, while C_22:6 is the dominant polyenoic fatty acid and C_20:5 the second most plentiful in hake lipids. Phospholipids form a small proportion of the lipid from dark muscle. They are particularly rich in the fatty acids C_16:0 and C_22:6.     

THE ORIGIN OF THE MEDIUM CHAIN LENGTH FATTY ACIDS PRESENT IN BEER

The medium chain length fatty acids that are excreted during fermentation are produced by synthesis and not by degradation. The fermentation of a wort supplemented with propionic acid (C₃) or valeric acid (C₅) leads to the excretion of nonanoic acid (C₉) in addition to the usual even chain acids. C₉ acid was not detected in the beer when the inoculated yeasts contained a high proportion of pentadecanoic acid (C₁₆) and heptadecanoic acid (C₁₇) or when the C₁₇ acid was added to the wort, demonstrating that a degradative route is unimportant. The content of the medium chain length fatty acids in beer varies directly with their content in yeast; thus the fatty acid composition of the beer reflects changes in the content of these acids in yeast brought about by alteration in the supply of oxygen or by the addition of C3 acid to wort.     

The fatty acid composition of the main phospholipid fractions of the rumen and abomasum tissues of foetal and adult sheep

The fatty acid composition has been determined on phosphatidyl choline, phos-phatidyl ethanolamine and sphingomyelin fractions earlier isolated from the rumen and abomasum tissues of foetal and of adult Romney sheep. The major proportion of polyunsaturated fatty acids was found in the phosphatidyl ethanolamine (17 to 43%) fraction and this was reduced in the phosphatidyl choline (7 to 25%) and sphingomyelin (1 to 4%) fractions. These features are in keeping with the results for mammalian tissues generally. The phosphatidyl ethanolamine fractions were further characterised by the low content of palmitic acid (<8%) compared with 25 to 30 % in the phosphatidyl choline fractions and 29 to 52% in the sphingomyelin fractions and by the occurrence of cyclopropane fatty acids. Consistent with the findings of other workers on mammalian tissues, the sphingomyelin fractions contained a relatively high content (16 to 27%) of higher w-saturated fatty acids including 22:0,23:0,24:0 and 25:0 and of tetracos-14-enoic (24:1 ω9) acid (5 to 16%). The total amounts of acids above C₂₀ tended to vary inversely with the levels of palmitic acid whereas the levels of stearic acid were relatively constant at 13 to 17%. Changes in fatty acid composition with age were generally not marked but the tissues of the foetus were distinguished from those of the foetus were distinguished from those of the adult by their substantial amount of eicosa-5,8,11-trienoic (20:3 ω9) acid together with relatively low contents of linoleic (18:2 ω6) and linolenic (18:3 ω3) acids and to a leser extent by reduced level of acids of the ω3 series. This was particularly reflected by the ratios of ω6/ω3 C₂₀ + C₂₂ acids in the phosphatidyl ethanolamine fractions, the valucs for the foetal rumen and abomasum tissues being 1.03 and 1.07, respectively, compared with corresponding values of 0.78 and 0.72 found in adult sheep. The results are consistent with a requirement for C₂₀ and C₂₂ polyunsaturated acids of the ω3 and ω6 series and some penetration of maternal fatty acids through the placenta. The resemblance between the fatty acid make-up and composition of foetal and maternal phospholipids suggests the possibiligy of transference of intact or lyso-phospholipids from the mother to the foetus through the placenta. However, such a possibility is counter-indicated by consideration of previous work using labelled intermediates and by the mechanism of conversion of linoleic and linolenic acids requiring their CoA derivatives in the formation of the corresponding polyunsaturated C₂₀ + C₂₂ acids. Nevertheless, the sharp cut-off of exogenous maternal fatty acids from the foetal triglycerides and their inclusion in the foetal phospholipids are not readily explainable.     

Fatty Acids of Neutral and Phospholipids, Rancidity Scores and TBA Values as Influenced by Packaging and Storage

The fatty acid (FA) of neutral lipids (NL) and phospholipids (PL) and this composition's relationship to rancidity score and TBA values of cooked beef patties, during frozen storage at times up to 4½ months under vacuum and nonpackaged conditions were studied. The predominant FA in the NL was C_18:1 (46.0%), followed by C_16:0 at 29.2%. However, the PL fraction gave a more balanced distribution of FA. In the neutral lipid fractions, reduction in the C_16:1 and C_18:2 fatty acids made significant contributions to increased rancidity scores and TBA values but in the phospholipid fraction, changes in the C_18:3 and C_20:4 were of greatest importance. After 3 months of frozen storage a regression model containing the neutral lipid fatty acids C_18:1 and C_18:2 and the phospholipid fatty acids C_18:3 and C_20:4 accounted for 88% and 85% of the variation in rancidity score and TBA value.     

Fractionation of buffalo butter oil by supercritical carbon dioxide

Buffalo butter oil was fractionated by supercritical carbon dioxide into four fractions (F₁-F₄). Fractionation was performed at 50 and 70 °C over a pressure range of 10.9-40.1 MPa. Short chain fatty acids (C₄-C₈), medium chain fatty acids (C₁₀-C₁₄) and saturated fatty acids were decreased from F₁ to F₄, while long chain fatty acids (C₁₆-C_18:3) and unsaturated fatty acids were increased. Triacylglycerol molecular species exhibited a similar trend as fatty acids. Cholesterol was concentrated in F₁, and with increasing the fluid density, it decreased by more than 50% in F₄. Substantial changes occurred in the chemical composition of the fractions led to distinctive differences in their thermal profile and solid fat content. Fractions obtained in the initial stages of the fractionation exhibited lower melting behavior that obtained in the late stages.