Effect of high-temperature degradative processes on ketocarotenoids present in paprika oleoresins

Carotenoid pigments in six commercial oleoresins, qualitatively uniform in pigment composition, were thermodegraded to determine the degradation kinetics in the two (red and yellow) isochromic fractions, structurally differentiated by the presence or absence of keto groups. The different rate of degradation of total pigment indicates that the oily medium modulates the degradation reaction differently, so that each oleoresin shows a different stability. However, in all the oleoresins, the red pigment fraction is degraded at a higher rate than the yellow. Arrhenius curves reveal an isokinetic temperature (T(isok)) distinguishing two zones in which the degradation process has a different effect on each fraction. At temperatures above T(isok), degradation is preferentially toward the red fraction, while at lower temperatures, it is toward the yellow fraction. An isokinetic point between the two pigment fractions means that the thermal conditions at which the stability of the system is to be determined must be stated, as such conditions produce a different effect on each fraction.     

Quantitaive and qualitative changes associated with heat treatments in the carotenoid content of paprika oleoresins.

Quantitative changes in the red and yellow carotenoid pigment fractions of four paprika oleoresins were studied at four storage temperatures. At all four temperatures, there was an overall loss of pigmentation, which was more marked with increasing temperature. However, pigmentation loss was not qualitatively uniform. At temperatures below 60 degrees C, the rate of destruction of the yellow pigment fraction was higher than that of the red pigments. Above 60 degrees C, the order of lability of the two fractions was inverted and the red pigment fraction became the more unstable. Thus, treatments above this temperature increase the proportion of yellow pigments. Any heat treatment results in a decrease in the total pigment concentration, with the initial proportion of red and yellow pigments switching in favor of one or the other depending on the temperature used.     

Rapid spectrophotometric determination of red and yellow isochromic carotenoid fractions in paprika and red pepper oleoresins

A rapid method has been developed for the determination of the red (R) and yellow (Y) isochromic carotenoid pigments fractions in paprika and oleoresins, based on UV-visible spectrophotometric measurement at two characteristic wavelengths and application of the Lambert-Beer law for multicomponent mixtures. The wavelengths 472 and 508 nm were selected as the most appropriate for simultaneous quantification of these fractions in the acetone extract of pigments. Experimental determination of the specific absorption coefficients (epsilon) for the two pigment fractions (R, Y) at 472 and 508 nm yielded equations to calculate the concentration of the two fractions, the total pigment content, and the ratio between the two fractions. The error in the determination of the isochromic fractions by the proposed spectrophotometric method was <5% when the results were compared with those obtained by HPLC analysis. The method can be applied to the direct extract of pigments, thereby avoiding saponification and minimizing errors from pigment degradation and sample manipulation as well as shortening the time of analysis (5 min in the case of oleoresins).     

Cholesterol oxides,cholesterol, total lipid,and fatty acid composition in turkey meat

The contents of cholesterol oxides, cholesterol, and total lipid, and the fatty acid composition were determined in frozen turkey meat. The 7-ketocholesterol content varied from 33 microg/100 g in the breast to 765 microg/100 g in the skin, and the levels of 7 beta-hydroxycholesterol varied from not detected in the leg, breast, and skin to 370 microg/100 g in the skin. The values for total lipid (g/100 g) in the wings, legs, breast, and skin were 0.9 +/- 0.4, 1.1 +/- 0.2, 0.5 +/- 0.1, and 12 +/- 3, respectively. The contents for cholesterol (mg/100 g) were 46 +/- 5, 35 +/- 2, 27 +/- 3, and 81 +/- 6 in the wing, legs, breast, and skin, respectively. The main fatty acids identified in all cuts were C18:2n6, C18:1n9, C16:0, C18:0, and C20:4n6.     

饲粮油脂对蛋鸡生产性能、血清脂质含量和蛋黄脂肪酸组成的影响

选用90只50周龄海蓝褐壳蛋鸡,随机分成5组。5组饲粮中分别添加使用2%棕榈油(对照组,2%PO)、2%亚麻油(2%LO)、4%亚麻油(4%LO)、4%鱼油(4%FO)、4%火麻仁油(4%HO),研究不同油脂对蛋鸡生产性能、蛋黄中脂肪酸组成和血清胆固醇等脂质含量的影响。结果表明:(1)4%亚麻油组鸡产蛋率较对照组提高,差异显著(P<0.05),4%鱼油组和2%亚麻油组产蛋率与对照组差异不显著(P>0.05)。(2)与对照组比较,随着饲粮亚麻油用量的增加,蛋黄中α亚麻酸(ALA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)的含量增加(P<0.05);4%鱼油组蛋黄中EPA和DHA含量增加(P<0.05);4%火麻仁油组蛋黄中亚油酸(LA)和ALA的含量增加(P<0.05)。(3)饲粮中不同油脂影响蛋黄中n6/n3多不饱和脂肪酸(PUFA)比值,亚麻油、鱼油、火麻仁油能降低n6/n3PUFA比值(P<0.05)。(4)不同油脂对血清脂质含量无显著的影响(P>0.05),但亚麻油、鱼油、火麻仁油有降低血清总胆固醇、低密度脂蛋白胆固醇和甘油三酯的含量,提高高密度脂蛋白胆固醇浓度的趋势。     

Improving the fatty acid profile of fairy shrimp, Streptocephalus dichotomus, using a lipid emulsion rich in highly unsaturated fatty acids

Fatty acids are the largest component of lipids and have become a useful tool in the determination of live feeds to a variety of cultured species. Bioencapsulation is a technique which allows high-level incorporation of desired components (i.e., fatty acids, vitamins, antibiotics, etc.) in live feeds, which in turn can be supplemented to the consumer organisms. The procedure described in the present study serves as a platform of technology for enriching the Streptocephalus dichotomus. Uptake of two enrichment diets (ALGAMAC2000 and DHA-SELCO) by adult S. dichotomus was investigated. The fatty acid profile supports the hypothesis that the enrichment diet increases the level of essential fatty acids, such as linolic, linolenic, eicosapentenoic, and docosahexaenoic acids. The average content (percent of total fatty acids detected) of the enriched organism by different highly unsaturated fatty acid (HUFA) products were as follows: ALGAMAC2000 showed 14-22% saturated fatty acid (SFA), 17-18% monounsaturated fatty acid (MUFA), 28-41% polyunsaturated fatty acid (PUFA), 23-34% n-3, and 4.9-7.5% n-6, whereas DHA-SELCO showed about 20-23% SFA, 20-26% MUFA, 38% PUFA, 28-31% n-3, and 7.5-10% n-6. Our present investigation proves that both HUFA-rich diets appear to be an appropriate enrichment diet, and further provides an additional rationale for using fairy shrimp as a maturation diet for any cultivable freshwater organism.     

Changes in fatty acid composition with age and environment in different types of peat profiles in Japan

Fatty acid composition of the crude lipid fraction of peat was investigated using several typical peat profiles in Japan. Fatty acid composition varied with the peat layers accumulated in a peat profile since 32,000 years BP. Deposition of long-range transported volcanic ash tephras also affected the composition remarkably due to the acceleration of decomposition. Fatty acid composition differed among high moor, transitional moor, and low moor peat profiles sampled in several locations in Hokkaido, Japan. The difference in the plants involved in the formation of peat was considered to be a very important factor determining the fatty acid composition. For example, arachidic acid was considered to be a good indicator for the presence of reed, while the percentage of stearic acid tended to be high in the high moor peat profiles dominated by sphagnum. As the fatty acids with a longer chain length were more stable than those with a shorter chain length, the percentage of longer fatty acids (C24 and C26) tended to increase and that of shorter fatty acids (CI4 and CI6) to decrease in the lower peat profiles. The drying of peatland also exerted a similar effect on the fatty acid composition.     

Effect of the polyunsaturated fatty acid composition of beef muscle on the profile of aroma volatiles

The effect of n-3 polyunsaturated fatty acids (PUFAs) in beef muscle on the composition of the aroma volatiles produced during cooking was measured. The meat was obtained from groups of steers fed different supplementary fats: (i) a palm-oil-based control; (ii) bruised whole linseed, which increased muscle levels of alpha-linolenic (C18:3 n-3) and eicosapentaenoic acid (EPA, C20:5 n-3); (iii) fish oil, which increased EPA and docosahexaenoic acid (C22:6 n-3); (iv) equal quantities of linseed and fish oil. Higher levels of lipid oxidation products were found in the aroma extracts of all of the steaks with increased PUFA content, after cooking. In particular, n-alkanals, 2-alkenals, 1-alkanols, and alkylfurans were increased up to 4-fold. Most of these compounds were derived from the autoxidation of the more abundant mono- and di-unsaturated fatty acids during cooking, and such autoxidation appeared to be promoted by increased levels of PUFAs.     

Effect of brown seaweed lipids on fatty acid composition and lipid hydroperoxide levels of mouse liver

Brown seaweed lipids from Undaria pinnatifida (Wakame), Sargassum horneri (Akamoku), and Cystoseira hakodatensis (Uganomoku) contained several bioactive compounds, namely, fucoxanthin, polyphenols, and omega-3 polyunsaturated fatty acids (PUFA). Fucoxanthin and polyphenol contents of Akamoku and Uganomoku lipids were higher than those of Wakame lipids, while Wakame lipids showed higher total omega-3 PUFA content than Akamoku and Uganomoku lipids. The levels of docosahexaenoic acid (DHA) and arachidonic acid (AA) in liver lipids of KK-A(y) mouse significantly increased by Akamoku and Uganomoku lipid feeding as compared with the control, but not by Wakame lipid feeding. Fucoxanthin has been reported to accelerate the bioconversion of omega-3 PUFA and omega-6 PUFA to DHA and AA, respectively. The higher hepatic DHA and AA level of mice fed Akamoku and Uganomoku lipids would be attributed to the higher content of fucoxanthin of Akamoku and Uganomoku lipids. The lipid hydroperoxide levels of the liver of mice fed brown seaweed lipids were significantly lower than those of control mice, even though total PUFA content was higher in the liver of mice fed brown seaweed lipids. This would be, at least in part, due to the antioxidant activity of fucoxanthin metabolites in the liver.     

Comparison of lipid content and fatty acid composition between Tuber fermentation mycelia and natural fruiting bodies

A comparison of lipid content and fatty acid (FA) composition between Tuber fermentation mycelia and natural fruiting bodies indicates that the lipid content in Tuber fermentation mycelia is higher than that in fruiting bodies. Unsaturated FAs (particularly linoleic acid and oleic acid) were the predominant constituents in total FAs in both Tuber fermentation mycelia and fruiting bodies. A total of 23 FAs, including arachidonic, eicosapentaenoic, docosahexaenoic, and γ-linolenic acids, were first identified in the Tuber species. A hierarchical clustering analysis showed that the FA profile of fermentation mycelia was quite similar, regardless of Tuber species. However, the FA profile of the fruiting bodies was significantly influenced by its species and habitat environments. Interestingly, the FA profile of the Tuber indicum and Tuber aestivum fruiting bodies was nearly identical to that of the Tuber fermentation mycelia, which partially confirms the similarity between the Tuber fermentation mycelia and the fruiting bodies.     

Characterization of sphingolipids from sunflower seeds with altered fatty acid composition

Sphingolipids are a group of lipids that are derived from long-chain 1,3-dihydroxy-2-amino bases and that are involved in important processes in plants. Long-chain bases are usually found bound to long-chain fatty acids forming ceramides, the lipophilic moiety of the most common sphingolipid classes found in plant tissues: glucosyl-ceramides and glucosyl inositol phosphoryl-ceramides (GIPCs). The developing sunflower seed kernel is a tissue rich in sphingolipids, although, importantly, its glycerolipid composition can vary if some steps of the fatty acid synthesis are altered. Here, the sphingolipid composition of the seed from different sunflower mutants with altered fatty acid compositions was studied. The long-chain base composition and content were analyzed, and it was found to be similar in all of the mutants studied. The sphingolipid species were also determined by mass spectrometry, and some differences were found in highly saturated sunflower mutants, which contained higher levels of GIPC, ceramides, and hydroxyl-ceramides.     

Effect of lipid composition on meat-like model systems containing cysteine, ribose, and polyunsaturated fatty acids

This paper compares the volatile constituents of model systems containing the important meat aroma precursors cysteine and ribose, with and without either methyl linoleate, an n-6 fatty acid, or methyl alpha-linolenate, an n-3 acid, both of which are present in meat. Many of the volatile compounds formed from the reaction between cysteine and ribose were not formed, or formed in lower amounts, when lipid was present. This may be due to the reaction between hydrogen sulfide, formed from the breakdown of cysteine, and lipid degradation products. In addition, cysteine and ribose modified lipid oxidation pathways, so that alcohols and alkylfurans were formed rather than saturated and unsaturated aldehydes. Several volatile compounds, which have been found at elevated levels in cooked meat from animals fed supplements high in n-3 acids, were formed when methyl alpha-linolenate reacted with cysteine and ribose. The possible effects of increasing the n-3 content of meat upon flavor formation during cooking are discussed.     

Transformation kinetics of corn and clover residues in mineral substrates of different composition

Mineralization kinetics of corn and clover residues in quartz sand, loam, sand + 15% bentonite, and sand + 30% kaolinite have been studied. A scheme has been proposed for the transformation of plant residues in mineral substrates. Kinetic parameters of mineralization have been calculated with the use of a first-order two-term exponential polynomial. It has been shown that the share of labile organic carbon pool in the clover biomass is higher (57–63%) than in the corn biomass (47–49%), which is related to the biochemical composition of plant residues. The mineralization constants of clover residues generally significantly exceed those of corn because of the stronger stabilization of the decomposition products of corn residues. The turnover time of the labile clover pool (4–9 days) in all substrates and that of the labile corn pool (8–10 days) in sands and substrates containing kaolinites and bentonite are typical for organic acids, amino acids, and simple sugars. In the loamy substrate, the turnover time of labile corn pool is about 46 days due to the stronger stabilization of components of the labile pool containing large amounts of organic acids. The turnover time of the stable clover pool (0.95 years) is significantly lower than that of the stable corn pool (1.60 years) and largely corresponds to the turnover time of plant biomass.     

Growth,ion accumulation,and lipid composition of two olive genotypes under salinity 1

Olive (Olea europaea L cv. Leccino and cv. Frantoio) plants grown in aeroponic cultivation system were supplied with Hoagland solutions containing 0 and 150 mM NaCl for 4 weeks. Sodium (Na⁺), chloride (Cl^‐), and potassium (K⁺) concentration was measued on 15‐day‐old leaves and K⁺/Na⁺ selectivity ratio was calculated. Plant water relations were estimated on the same leaves by measuring leaf bulk water and osmotic potentials, and by calculating leaf turgor pressure. Root and leaf tissues were also analysed for lipid composition, estimating free sterol (FS), glycolipid (GL) and phospholipd (PL) content. The salt‐sensitive Leccino accumulated more Na⁺ and Cl^‐ in the leaves and showed a lower K⁺/Na⁺ selectivity ratio than the salt‐tolerant Frantoio. The FS/PL ratio and the content of GL (namely mono‐galactosyldiglyceride, MGDG) in the roots were related to the salt accumulation in the shoot. Salinity‐induced changes on root lipids were more important in Frantoio than in Leccino, indicating the specific role of the roots in salt exclusion mechanisms. Conversely the effect of salinity on leaf lipid composition was more important in the leaves of the salt‐sensitive Leccino.     

Characterization of soil microbial communities under different potato cropping systems by microbial population dynamics, substrate utilization, and fatty acid profiles

The effects of 11 different 2- and 3-yr potato crop rotations on soil microbial communities were characterized over three field seasons using several techniques. Assessments included microbial populations determined by soil dilution plate counts on various general and selective culture media, microbial activity by fluorescein diacetate (FDA) hydrolysis, single carbon source substrate utilization (SU) profiles, and fatty acid methyl ester (FAME) profiles. Potato rotation crops evaluated in research plots at Newport, ME, included barley/clover, canola, green bean, millet, soybean, sweet corn, and a continuous potato control. Soil populations of culturable bacteria and overall microbial activity tended to be highest following barley, canola, and sweet corn rotations, and lowest with continuous potato. Differences among rotations were less apparent during the potato phase of the rotations. Populations of actinomycetes and fluorescent pseudomonads tended to be greater in barley rotations than in most other rotations. SU profiles derived from BIOLOG GN2 plates indicated that certain rotations, including barley, canola, and sweet corn tended to have higher overall microbial activity, and barley and sweet corn rotations averaged higher substrate richness and diversity. Soybean and potato rotations tended to have lower substrate richness and diversity. Principal component analyses of SU data revealed differences among rotation soil communities in their utilization of individual carbon sources and substrate guilds, including carbohydrates, carboxylic acids, amines/amides, and amino acids. Analyses of soil FAME profiles demonstrated distinct differences among all the rotation soils in their relative composition of fatty acids, indicating differences in their microbial community structure. Fatty acids most responsible for differentiation among rotation soils included 16:1 ω5c, 16:1 ω7c, 18:2 ω6c, 18:1 ω9c, 12:0, and 13:0 anteiso, with 16:1 ω5c being the single greatest determinant. Overall, monounsaturated fatty acids, particularly 16:1 ω5c, were most prevalent in sweet corn rotations and polyunsaturates were highest in barley and millet rotations. Straight chain saturated fatty acids comprised the greatest proportion of fatty acids in soils under continuous potato. FAME biomarkers for microorganism groups indicated barley and millet rotations had the highest ratio of fungi to bacteria, and soybean and continuous potato had the lowest ratio. This research has demonstrated that different crop rotations have distinctive effects on soil microbial communities that are detectable using a variety of techniques. Further studies will identify more specific changes associated with particular rotations and relate these changes to potential effects on disease management, crop health, and crop productivity.     

甘蔗对不同基质肥源氮、磷、钾的吸收和利用

对甘蔗进行直接浇灌不同浓度糖蜜酒精废液处理、常规施用化肥和不施肥处理,研究直接浇灌糖蜜酒精废液对甘蔗前期生长的影响.结果表明:苗期糖蜜酒精废液对甘蔗芽萌发、幼苗生长和对氮、磷、钾的吸收有一定胁迫作用,但该抑制作用随甘蔗生长可通过其自身代谢解除;到分蘖盛期,胁迫作用解除后,施用糖蜜酒精废液的甘蔗叶片氮、磷、钾含量高于对照和常规施肥,促进了甘蔗分蘖和伸长,提高了蔗茎产量,最终甘蔗产量显著高于对照,与常规施用化肥处理相当.说明适宜浓度的糖蜜酒精废液可直接施用于甘蔗,新植蔗以浇灌45 t·hm-2糖蜜酒精废液+60 t·hm-2清水最好,宿根蔗则以浇灌105 t·hm-2糖蜜酒精废液最好.     

分提橄榄油中主要脂肪酸成分傅里叶变换红外光谱法测量（英）

为了测量从橄榄油中分提的高、低熔点油脂的脂肪酸成分,在4 000～600 cm-1 的范围测量了31个含有不同脂肪酸成分植物油的傅里叶变换红外光谱,用于建立偏最小二乘（PLS）回归分析校正模型。在油脂的傅里叶变换红外光谱变量和脂肪酸组成变量之间建立了交叉验证的PLS校正模型。为了校正油酸和亚油酸含量,在4?000～600 cm-1 的频率范围,经平滑,二阶导数,规范化处理的红外光谱获得了最好的交叉验证校正模型和最佳的预测结果。PLS校正模型预测结果表明,与高熔点橄榄油（油酸,72.29%,亚油酸,9.98%）相比,低熔点橄榄油含有较高的油酸含量和亚油酸含量（油酸,77.46%,亚油酸,12.51%）,预测的结果与气相色谱测量的结果有很好的一致性。建立的PLS校正模型预测橄榄油的不饱和脂肪酸含量具有较好的相关性。该研究为分提油脂质量的判别评价提供了便捷的方法。