Nutritional effects of enzymatically modified soybean oil with caprylic acid versus physical mixture analogue in obese Zucker rats

Enzymatically modified soybean oil with caprylic acid (SL), a physical mixture of tricaprylin and soybean oil (PHY), and soybean oil as control were fed (20% of diet weight) to female obese Zucker rats. Both lipids (SL and PHY) have similar total fatty acid composition containing 23.4 mol % caprylic acid (C8:0) but have different lipid structures. After 21 days of feeding, the body weight gain was 36.4% in the SL-fed group and 35.2% in the PHY-fed group, respectively; whereas the body weight of the control group increased 41.6%. Significant differences in the respiratory exchange ratio were observed between the SL and PHY groups. However, the contents of glucose, total and high density lipoprotein (HDL) cholesterol, and very low density and low density lipoprotein (VLDL + LDL) cholesterol in serum were not significantly different between the SL- and PHY-fed groups or among the three dietary groups (control, SL, and PHY) (p < 0.05). On the other hand, plasma total cholesterol and plasma triacylglycerol (TAG) were significantly higher in SL- and PHY-fed groups than in the control group. In the liver and inguinal adipocyte TAG, C8:0 was found in the SL-fed group, whereas it was not observed in the liver and inguinal adipocyte TAG of the PHY-fed group, which suggests that positional distribution of C8:0 of the TAG molecule is an important consideration in the metabolism of lipids. This study showed that different positional distribution in TAG molecules lead to different metabolic fates, resulting in the change of fatty acid composition in liver and inguinal adipose TAG in female Zucker rats.     

Chemical interesterification of blends of palm stearin, coconut oil, and canola oil: physicochemical properties

trans-Free interesterified fat was produced for possible usage as a margarine. Palm stearin, coconut oil, and canola oil were used as substrates for chemical interesterification. The main aim of the present study was to evaluate the physicochemical properties of blends of palm stearin, coconut oil, and canola oil submitted to chemical interesterification using sodium methoxide as the catalyst. The original and interesterified blends were examined for fatty acid composition, softening and melting points, solid fat content, and consistency. Chemical interesterification reduced softening and melting points, consistency, and solid fat content. The interesterified fats showed desirable physicochemical properties for possible use as a margarine. Therefore, our result suggested that the interesterified fat without trans-fatty acids could be used as an alternative to partially hydrogenated fat.     

Characteristics of structured lipid prepared by lipase-catalyzed acidolysis of roasted sesame oil and caprylic acid in a bench-scale continuous packed bed reactor

Structured lipid (SL) was prepared from roasted sesame oil and caprylic acid (CA) by Rhizomucor miehei lipase-catalyzed acidolysis in a bench-scale continuous packed bed reactor. Total incorporation and acyl migration of CA in the SL were 42.5 and 3.1 mol %, respectively, and the half-life of the lipase was 19.2 days. The SL displayed different physical and chemical properties, less saturated dark brown color, lower viscosity, lower melting and crystallization temperature ranges, higher melting and crystallization enthalpies, higher smoke point, higher saponification value, and lower iodine value, in comparison to those of unmodified sesame oil. The oxidative stability of purified SL was lower than that of sesame oil. There were no differences in the contents of unsaponifiables including tocopherols and phytosterols. However, total sesame lignans content was decreased in SL due to the loss of sesamol when compared to sesame oil. Most of the 70 volatiles present in roasted sesame oil were removed from SL during short-path distillation of SL. These results indicate that the characteristics of SL are different from those of original sesame oil in several aspects except for the contents of tocopherols and phytosterols.     

trans-Free margarines prepared with canola oil/palm stearin/palm kernel oil-based structured lipids

Structured lipids (SLs) for formulating trans-free margarines were synthesized by lipase-catalyzed interesterification of the blends of canola oil (CO), palm stearin (PS), and palm kernel oil (PKO) in weight ratios (CO/PS/PKO) of 40:60:0, 40:50:10, 40:40:20, 40:30:30, 50:30:20, and 60:25:15. The atherogenicity was determined using fatty acid profiles. We also determined the physical properties (melting/crystallization profiles, solid fat content, polymorphism, and microstructure) of SLs and the textural properties of margarines made with the SLs. The SLs from the 50:30:20 and 60:25:15 blends had atherogenic indices similar to or lower than those of the commercial trans (CTMF) and similar to the trans-free margarine fats (CTFMF). SLs from the blends with PKO contained a wide range of fatty acids (C6-C20) and had more beta' than beta polymorphs. Margarines made with SLs from 50:30:20 and 60:25:15 blends possessed similar hardness, adhesiveness, or cohesiveness to margarines made with CTMF and CTFMF, respectively. Therefore, CO/PS/PKO-based SLs were suitable for formulating trans-free margarines with low atherogenicity and desirable textural properties.     

Effects of soil tillage,canola (Brassica napus L.) cultivars and planting date on canola yield,and oil and some biological and physical properties of soil

Determination of different agronomical properties including soil-related parameters for enhanced canola (Brassica napus L.) production can be of great significance. Hence, the objectives were to determine the effects of different tillage systems, canola cultivars and different planting dates on: (i) canola yield and oil, and (ii) soil moisture and microbial carbon (C) and nitrogen (N). Two field experiments were planned as split-plot experiments in three replicates. The main plots were different tillage systems including no-tillage (NT), minimum tillage (MT) and conventional tillage (CT), and the subplots were the combination of different canola cultivars (PF and Hyola 401) and different planting dates (PD): 8 and 23 September and 7 October. Soil moisture under CT and PF was significantly less than that of MT and NT, and Hyola 401, respectively. Carbon and N microbial biomass was the highest at NT and on the first PD. The tillage method and planting date also significantly affected canola yield, oil content and the amount, and the number of earthworms. We may conclude that although the amount of yield was the highest at CT, it may be more agronomically sustainable to plant canola under NT or MT earlier during the autumn growing season.     

Antioxidant properties of a radical-scavenging peptide purified from enzymatically prepared fish skin gelatin hydrolysate

Hoki (Johnius belengerii) skin gelatin was hydrolyzed with three commercial enzymes to identify radical-scavenging potencies of derived peptides. Peptides derived from tryptic hydrolysate exhibited the highest scavenging activities on superoxide, carbon-centered 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assessed by ESR spectroscopy. Following consecutive chromatographic separations of tryptic hydroolysate, the peptide sequence His-Gly-Pro-Leu-Gly-Pro-Leu (797 Da) acted as a strong radical scavenger under studied conditions. Further, this peptide could act as an antioxidant against linoleic acid peroxidation and the activity was closer to the highly active synthetic antioxidant butylated hydroxytoluene (BHT). In addition, antioxidative enzyme levels in cultured human hepatoma cells were increased in the presence of this peptide and it was presumed to be the peptide involved in maintaining the redox balance in the cell environment. Present data indicate that free-radical-scavenging activities of hoki skin gelatin peptides substantially contribute to their antioxidant properties measured in different oxidative systems.     

Chemical composition and antioxidant properties of clove leaf essential oil

The antioxidant activity of a commercial rectified clove leaf essential oil (Eugenia caryophyllus) and its main constituent eugenol was tested. This essential oil comprises in total 23 identified constituents, among them eugenol (76.8%), followed by beta-caryophyllene (17.4%), alpha-humulene (2.1%), and eugenyl acetate (1.2%) as the main components. The essential oil from clove demonstrated scavenging activity against the 2,2-diphenyl-1-picryl hydracyl (DPPH) radical at concentrations lower than the concentrations of eugenol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). This essential oil also showed a significant inhibitory effect against hydroxyl radicals and acted as an iron chelator. With respect to the lipid peroxidation, the inhibitory activity of clove oil determined using a linoleic acid emulsion system indicated a higher antioxidant activity than the standard BHT.     

Chemical and physical properties of coastal alluvial soils of new brunswick

Soils in the coastal alluvial area at the head of Bay of Fundy in New Brunswick, Canada, were characterized for their chemical and physical properties. A great variability in the electrical conductivity of the soil extract (E.C._e) was observed depending on the history of flooding. The correlation coefficient between E.C._e and sodium adsorption ratio (S.A.R.) was +0.89 (P < 0.01) but the correlation between S.A.R. and exchageable sodium percentage was only +0.36 (P < 0.05). Among the physical properties highly significant relationships were found between saturation percentage and fifteen atmosphere percentage (r = +0.86) and moisture equivalent and silt plus clay (r = +0.87).     

鱼油微胶囊射流空化制备工艺优化及理化性质研究

研究目的是以大豆分离蛋白为壁材,对射流空化制备鱼油微胶囊的工艺进行优化。采用喷雾干燥法,研究壁材添加量、乳化剂添加量、芯材添加量及射流空化处理时间对乳液稳定性和鱼油微胶囊包埋率的影响,通过响应面试验分析各因素,得到最优微胶囊制备工艺,并对制备的微胶囊产品同市售产品的结构、理化特性及稳定性进行对比分析。结果表明:在壁材添加量3.21%、乳化剂添加量0.21%、芯材添加量19.70%、射流空化处理时间11.25 min工艺条件下得到的乳液稳定性较好,鱼油微胶囊的包埋率达到94.14%。微胶囊产品微观结构呈球形颗粒,结构致密,颗粒形态完整,粒径小,表面含油率较低,包埋效果好;水分含量为3.07%,溶解度为96.30%,休止角为40.39?,溶解性较好;差示扫描量热分析结果显示,微胶囊热溶解温度较高,可用于常温贮藏。包埋后的鱼油经加速贮藏试验表明微胶囊化可以提高鱼油的氧化稳定性,延长鱼油贮藏期。     

用于生物降解膜的聚己内酯与聚乳酸共混物制备及性能分析

聚乳酸农用薄膜在自然条件下能够降解为CO2和H2O,可以有效地避免传统农用薄膜废弃后造成的土壤和环境污染。将聚己内酯与聚乳酸共混可以改善聚乳酸脆性强和韧性差的特点。该文将不同质量比例的聚己内酯(polycaprolactone,PCL)和聚乳酸(polylactic acid,PLA)熔融共混后通过注射成型工艺制备了农业薄膜用PCL/PLA共混物,研究了PCL与PLA配比对共混物力学性能、热稳定性、结晶熔融行为以及表面润湿性的影响。结果表明:随着PCL含量增加,共混物的拉伸强度逐渐下降,而拉伸断裂伸长率和冲击强度则先增大后减小。PCL质量分数为50%时,共混物拉伸断裂伸长率和冲击强度分别达到最大值11.2%和6.4 KJ/m2;扫描电镜分析显示,PCL与PLA相容差,聚酯连续相种类及优势共同主导力学性能走向;热重分析表明,PCL的引入有效减缓了共混物热解速率,PLA质量分数增加共混物燃烧成炭率增大;差示扫描量热法分析表明,相对于PCL和PLA,PCL/PLA共混物玻璃化转化温度、熔融温度和结晶温度均产生了变化,但二者配料比对3种温度影响不明显;接触角分析表明,PCL/PLA共混物接触角相比于PCL和PLA均有所增大,水润湿性能不同程度的降低。综合考虑,PCL与PLA最佳质量比为50∶50。研究可为农业薄膜用聚己内酯与聚乳酸共混物的制备提供依据。     

Enrichment of tocopherols and phytosterols in canola oil during seed germination

The effect of canola (Brassica napus L.) seed germination under illuminated and dark environments on the total concentration and the composition of tocopherols and phytosterols in seedlings and extracted oil were investigated. During the first 10 days of germination, a decrease in gamma-tocopherol was offset by an increase in alpha-tocopherol, indicating the interconversion of these isomers. From day 10 to day 20 under illumination, there was a net increase in alpha-tocopherol and total tocopherols suggesting the synthesis of new tocopherols, whereas there was no net increase in tocopherols in dark. Tocopherols were mainly concentrated in the leafy seedling tops rather than in the non-photosynthesizing bottoms, whereas phytosterols were equally distributed across both sections. The total tocopherol content of oil extracted from 20-day-old seedlings was 4.3- to 6.5-fold higher than that of intact seeds. On a dry seedling basis, the content and composition of phytosterols did not change significantly (p > 0.05) over the sprouting period, but the concentration of total phytosterols in the oil fraction increased 4.2- to 5.2-fold. The concentration of these valuable phytochemicals in the oil fraction is largely due to the depletion of oil reserves during germination, as well as the de novo synthesis of new alpha-tocopherol stimulated by the presence of light. Germination may represent a viable means to naturally concentrate these high-value constituents in canola oil, offering improvements in oil quality based on the nutritional value and oxidative protection offered by tocopherols and the health benefits provided by both tocopherols and phytosterols.     

Regioisomerism of triacylglycerols in lard, tallow, yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil analyzed by tandem mass spectrometry.

Triacylglycerols (TAG) of lard, tallow, egg yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil (82:18) were investigated by chemical ionization and collision-induced dissociation tandem mass spectrometry. Accurate molecular level information of the regioisomeric structures of individual TAGs was achieved. When existing in a TAG molecule of lard, palmitic acid occupied 90-100% of the sn-2 position. Within the major fatty acid combinations in tallow TAGs, the secondary position sn-2 was preferentially occupied in the decreasing order by oleoyl > palmitoyl > stearoyl residues, the order in saturated TAGs being myristoyl > stearoyl = palmitoyl. TAGs in egg yolk were more asymmetric than in chicken skin, with linoleic acid highly specifically attached in the yolk sn-2 carbon. Nearly 50% of yolk TAGs contained 52 carbon atoms with two or three double bonds. Linoleic, oleic, and palmitic acids were in the sn-2 location in decreasing quantities in palm oil and its fractions. Triacylglycerols of equal molecular weight behaved similarly in the fractionation process. Randomization of the parent oil TAGs was seen in the transesterified oil. The tandem mass spectrometric analysis applied provided detailed information of the distribution of fatty acids in individual combinations in TAGs.     

Celiac-related properties of chemically and enzymatically modified gluten proteins

The effects of chemical (acid-heating treatment) and enzymatic (microbial transglutaminase, TGase) modification (deamidation) of gluten proteins on their physicochemical and celiac disease-related properties were studied. Ammonia release, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and sample solubility analyses were employed to check the extent of gluten modification. Among different treatments achieved, the acid-heating treatment performed at 90 degrees C for 3 h induced gluten deamidation, paralleling an increase of gluten solubility without relevant proteolysis. Changes in the immunoreactivity of celiac IgA anti-gliadin antibodies (AGAs) to modified gluten proteins were detected by using a competitive indirect enzyme-linked immunosorbent assay method. Chemical deamidation by acid-heating treatment of gluten lowered IgA-AGA immunoreactivity. IgA-AGA immunoreactivity to gliadins was increased when they were submitted to TGase-catalyzed deamidation. The acid-heating treatment of gluten reduced its cytotoxic activity on human colon adenocarcinoma LoVo cell line. These results showed that chemical deamidation of gluten may be envisaged as a way to lower the potential risk for celiac people due to widespread use of gluten as a food additive.     

Chemical compositions and physicochemical properties of the fiber-rich materials prepared from shoyu mash residue

Fiber-rich materials including desalted shoyu mash residue (briefly referred as desalted mash residue, DMR), alcohol-insoluble solid (AIS), and water-insoluble solid (WIS) were prepared from shoyu mash residue, which is a filtration cake obtained during the isolation of shoyu by press filtration of fermented matrix in the final process. The DMR, AIS, and WIS contain rich dietary fiber of 52.4, 61.5, and 54.7 wt %, respectively. The DMR, AIS, and WIS all have significantly lower bulk densities, and higher water-holding capacities, oil-holding capacities, swelling abilities, and cation-exchange capacities than the control cellulose. These results indicated that the said fiber-rich materials prepared in this study all have the desired physicochemical properties for being used as satisfactory sources of dietary fibers or low-calorie bulk ingredients in food applications requiring oil and moisture retention. Furthermore, the said fiber-rich materials also have high contents of isoflavones, mainly daidzein and genistein, which are considered as the most bioavailable phytoestrogens, with a total amount of about 1200-1480 micromol/100 g (equal to daidzein of ca. 3040-3759 microg/g, or genistein of 3240-3996 microg/g). The results revealed that the said fiber-rich materials might be a potent fiber source for health foods.     

Rheological properties of acid gels prepared from heated pH-adjusted skim milk

Reconstituted skim milk was adjusted to pH values between 6.5 and 7.1 and heated (90 degrees C) for up to 30 min. The skim milk samples were then readjusted to pH 6.7. Acid gels prepared from heated milk had markedly higher G ' values, a reduced gelation time, and an increased gelation pH than those prepared from unheated milk. An increased pH at heating decreased the gelation time, increased the gelation pH, and increased the final G ' of acid set gels prepared from the heated milk samples. There were only small differences in the level of whey protein denaturation in the samples at different pH values, and these differences could not account for the differences in the G ' of the acid gels. The levels of denatured whey protein associated with the casein micelles decreased and the levels of soluble denatured whey proteins increased as the pH at heating was increased. The results indicated that the soluble denatured whey proteins had a greater effect on the final G ' of the acid gels than the denatured whey proteins associated with the casein micelles.     

Effect of long-term dietary supplementation of high-gamma-linolenic canola oil versus borage oil on growth, hematology, serum biochemistry, and N-6 fatty acid metabolism in rats

Dietary supplementation of a high-gamma-linolenic acid canola oil (HGCO) containing approximately 36% (w/w) of gamma-linolenic acid (GLA, 18:3n-6) from the seeds of a genetically transformed canola strain, was assessed for its long-term biological effects. Growing Sprague-Dawley rats (n = 30) were fed a purified AIN93G diet containing 5, 10, or 15% (w/w) of HGCO as the fat source. For comparison, a separate group of rats (n = 10) was given the diet containing 15% (w/w) of borage oil (BO), which contained 22% (w/w) of GLA. After 12 weeks of feeding, the growth, relative organ weights, hematology, and serum biochemistry were found to be similar among rats fed the 5, 10, and 15% HGCO diets. The GLA levels in plasma and liver phospholipids (PL) were also similar. However, the levels of GLA in peripheral tissues (muscle PL and adipose triacylglycerols) were significantly higher in rats fed the 10 and 15% HGCO diets than those fed the 5% HGCO diet. When the above biologic parameters were compared between the 15% HGCO and 15% BO dietary groups, there were no significant differences except for lower final body weights and higher tissue levels of GLA, dihomo-gamma-linolenic acid (20:3n-6) and arachidonic acid (20:4n-6) in the 15% HGCO dietary group as compared with the 15% BO dietary group. This is due to a higher GLA content and possibly a more favorable stereospecific distribution of GLA in HGCO. Overall, long-term (12-week) feeding with diets containing up to 15% HGCO resulted in no adverse effects on growth, organ weight, hematology and serum biochemistry as compared to the diet containing 15% BO, suggesting that HGCO may be a safe alternative source of GLA.     

Effects of straw,vegetable oil and whey on physical and microbiological properties of a chernozem

A soil microcosm study was carried out to compare the effects of straw, vegetable oil or whey additions on physical and microbiological properties of a chernozem after 18 weeks of incubation. The application rates of the different organic materials were based on the addition of carbon at a concentration equivalent to 1% of soil dry mass.Straw, vegetable oil and whey additions to soil increased dry aggregate size distribution during incubation. All organic treatments had significantly higher mean weight diameter (MWD) of dry aggregates than the untreated control. The ability of whey, straw and oil to increase MWD did not differ significantly. Only straw addition significantly increased soil maximum water-holding capacity after 126 days of incubation. In comparison with the untreated control, straw tended to reduce the resistance of aggregates to abrasion, while addition of whey and vegetable oil seemed to have a positive effect on this property. Aggregates of organic matter amended soil materials had higher resistance to the dispersive action of water than those of the untreated control. Whey and straw additions sustained higher soil biomass-C contents and C_mic/C_org ratios than vegetable oil. Biomass development was most favored by whey addition. Fungal contributions to biomass-C dominated over bacterial contributions in whey and straw-amended soil. The opposite was observed for the oil treatment. Increases in MWD of dry aggregates seem to be related to the synthesis of biomass and soil binding metabolites in whey and straw-treated soil. Among the organic treatments, oil-amended soil had the highest respiratory activity and the lowest biomass content. Stabilizing agents derived from the microbial metabolism using oily substrate are discussed.     

控释尿素配施黄腐酸对小麦产量及土壤养分供应的影响

【目的】 控释尿素可调控氮素缓慢释放使其与作物养分吸收速率基本同步,黄腐酸可调控土壤与肥料养分转化,两者均能显著提高肥料利用率,然而控释尿素配伍黄腐酸对小麦的协同增效研究鲜有报道。本文研究控释尿素配施黄腐酸对小麦产量和土壤肥力的影响,为其科学施用提供依据。 【方法】 以小麦 (Triticum aestivum L.) 为试材进行了盆栽试验,供试土壤为棕壤。试验设不施氮 (CK)、尿素全量 (U)、尿素减量1/3(U2/3)、尿素全量及减量配施黄腐酸 (U + FA、U2/3 + FA)、控释尿素全量及减量 (CRU、CRU2/3)、控释尿素全量和减量配施黄腐酸 (CRU + FA、CRU2/3 + FA) 共9个处理。所有处理P₂O₅ 和K₂O施入量均为150 kg/hm2和75 kg/hm2,尿素全量处理为N 225 kg/hm2,黄腐酸处理黄腐酸用量为45 kg/hm2。控释尿素处理均为一次性基施,普通尿素处理于拔节期追施尿素,基追比为1∶1。于小麦苗期、返青期、拔节期、开花期和成熟期取0—20 cm土壤样品,测定土壤硝态氮、铵态氮含量,同时测定株高和叶片SPAD值,收获期调查了小麦产量和土壤养分含量。 【结果】 1) 控释尿素CRU、CRU2/3较等氮尿素U、U2/3处理产量平均显著增加7.3%,净收益显著提高24.9%;CRU2/3与处理U产量差异不显著;CRU + FA较CRU显著增产6.4%,净收益显著增加12.6%;与U2/3处理相比,U2/3 + FA显著增产10.6%;U + FA较U处理显著减产12.8%。2) 等氮条件下,CRU、CRU2/3处理与U、U2/3处理小麦株高、叶片SPAD值差异不显著,CRU + FA、CRU2/3 + FA与CRU、CRU2/3处理间差异均不显著。3) 拔节期,CRU、CRU2/3处理土壤硝态氮含量比等氮U、U2/3处理平均显著高出54.7%,CRU2/3处理与U处理差异不显著;配施黄腐酸处理U + FA、U2/3 + FA、CRU + FA、CRU2/3 + FA的土壤有效磷含量均呈现先降低后增加最后降低的趋势,拔节期CRU处理的土壤有效磷含量与U处理无显著差异,CRU2/3、U2/3 + FA的土壤有效磷含量较CRU处理显著提高了18.6% 和20.6%;拔节期U + FA、U2/3 + FA较等氮U、U2/3处理土壤pH平均显著降低了0.11个单位,其他时期U + FA和CRU + FA处理与等量单施化肥处理差异不显著。 【结论】 控释尿素配施黄腐酸可协同增效,满足小麦各生育期氮素需求,一次性基施显著提高小麦中后期土壤养分供应强度,显著提高了小麦产量、肥料利用率和净收益。