Chemical composition and nutritive value of the protein of Amaranthus quintensis

An account is given of some considerations concerning the chemical recognition and evaluation by biological methods of the quality of the flour obtained from Amaranthus quitensis seeds, submitted to grinding and sifting. The protein content of the flour (21.70g/100g) can be considered as very important, as well as that of the available lysine (5.20g/16gN). The calcium content was also remarkable (500mg/100g), and the starch ratio reached 45.00g/100g. The amount of nitrates found was 20.00mg/100g, which is an acceptable limit. The research for organic nitro compounds was negative. As for the biologic quality of the protein, the experiments revealed that it has quite an acceptable availability, as demonstrated by the following values: NPU = 42.50 +/- 6.10, D = 68.50 +/- 5.30, VB = 62, NPR = 2.10 +/- 1.80 and RNPR = 42.     

Study of drying kinetics of salmon processing by-products at different temperatures and the quality of extracted fish oil

Samples of salmon processing by-products were minced, mixed, and partially dried to moisture content of 90?±?5% (dry basis), at two different temperatures 60 and 100°C (using hot air-drying and oven-drying, respectively). Theoretical and semitheoretical drying models were used for modeling of the drying kinetics of salmon by-products mix, where Page model and logarithmic models were observed as the best models presenting the drying kinetics of salmon by-products at 60 and 100°C, respectively. Salmon by-product oil was extracted from the partially dried by-product through centrifugation and was compared with enzymatically extracted (enzymatic extraction method was considered as the control method) salmon oil, in terms of fatty acid profile of the oils. The oil content obtained through semidried samples and enzymatically treated samples ranged between 16.234 and 18.212?g/100?g of fresh sample, which were not significantly different. The fatty acid composition was similar in all the cases. The fatty acids predominantly observed in the salmon oils included oleic acid, linoleic acid, and palmitic acid. Other fatty acids included palmitoleic acid, stearic acid, vaccenic acid, gondoic acid, and myristic acid. Docosahexaenoic acid and eicosapentaenoic acid contents were between 1 and 2% of the oil extracted in all the cases, and DPA (Docosapentaenoic acid) content was approximately 1%. Hence, partial dehydration at both the temperatures was concluded as a potential processing method for increasing the storability of salmon by-products and obtaining salmon oil with high quality.     

Discovery of an 11(R)- and 12(S)-lipoxygenase activity in ovaries of the mussel Mytilus edulis

Eicosanoid biosynthesis was investigated in mussel gonads by incubation of tissue homogenates with radiolabeled arachidonic acid and analysis of the products by radio-high-performance liquid chromatography. No radiolabeled metabolites were formed in homogenates of testes, but two major metabolites were synthesized by ovarian preparations. The radiolabeled metabolites were analyzed by mass spectrometry and chiral chromatography and identified as 11(R)-hydroxy-5,8,12,14-eicosatetraenoic acid and 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid. In addition, four other nonlabeled metabolites, formed from endogenous substrates, were detected in ovarian extracts. Their structures, determined by mass spectrometric analysis, were the corresponding 11- and 12-hydroxy analogs formed from eicosapentaenoic acid (11-HEPE and 12-HEPE) and 9-hydroxy-6,10,12,15-octadecatetraenoic acid (9-HOTE) and 13-hydroxy-6,9,11,15-octadecatetraenoic acid formed from stearidonic acid. The biosynthesis of the 11- and 12-hydroxy products was calcium dependent, localized to the 100,000×g supernatant cell fraction, and was inhibited by nordihydroguaiaretic acid, but not inhibited by the prostaglandin synthase inhibitors aspirin and indomethacin, or the monoxygenase inhibitor proadifen. Together these data suggested that both the 11(R)- and 12(S)-hydroxy products were formed from lipoxygenase-type enzymes. Incubation of homogenates of immature ovaries with eicosapentaenoic acid revealed the major product to be 12-HEPE, whereas in mature ovaries mainly 11-HEPE was formed. Extraction of spawned eggs with methanol revealed that predominantly 11-HEPE and 9-HOTE were formed from endogenous substrates. This study shows that female gonads of the mussel express an 11(R)- and 12(S)-lipoxygenase activity whose expression is dependent on differentiation of the ovary.     

Effect of reheating on iron availability and the protein nutritive value of cooked black bean (Phaseolus vulgaris)]

In Guatemala, at the rural level, beans are prepared for family consumption every two days. Beans are cooked again every 12 hours for 15 minutes prior to their consumption. Due to the adverse effect that the process causes on nutritive value, the present study evaluated the method and preparation practice of beans on protein value; tannin and soluble and ionizable iron content. As to the effect of re-cooking on protein level, findings revealed that there were no significant statistical effects on net protein ratio (NPR) or in protein efficiency ratio (PER) and number of bean cooking. Nevertheless, a constant effect in quality in the first and second cooking procedure was detected. The second cooking gave a similar value as the first. Also, the first and second heating reduced protein digestibility, but the third gave a value similar to the initial one. No changes were observed in the digestibility of dry matter. Relatively high amounts of protein were found in the cooking broth, which was not affected by the number of heating. It was also found that the bean broth contained high levels of tannins in the initial heating, decreasing later significantly. The same was observed in the cooked beans alone and in beans with their broth. With respect to iron, findings showed a relatively high transference of beans to broth, in total iron as well as in soluble, ionizable and insoluble iron. No changes were observed in whole beans without broth caused by number of heatings, on total, soluble or ionizable iron. In beans with their broth, a similar effect was observed, although a slight increase in insoluble iron was detected at the end of heating. A decrease in soluble and insoluble iron was observed in broth with number of heatings. Correlations were calculated among the parameters studied, which suggested an effect of tannins on the bioavailability of iron caused by tannins.     

Influence of mixing sequence and superplasticiser dosage on the rheological response of cement pastes at different temperatures

An experimental methodology to study the rheological response of superplasticised cement pastes subjected to temperatures ranging from 5 to 45 °C is presented. The content of a polycarboxylate-based superplasticiser (PC) and moment of its addition to the mix (direct or delayed) are investigated. A loop of shear rate ramps is applied to each sample in order to obtain information about apparent viscosities and yield stresses, as well as a measure of their thixotropic behaviour. Results from the experimental campaigns indicate PC saturation dosages depend only slightly on temperature. The evolution of yield stress and thixotropy with temperature shows inverted trends under some conditions.     

Evaluation of the protein quality of Erythrina edulis (balú)

The protein content (N x 6.25) of the seeds of Erythrina edulis (balú) varies between 18-21%; when the fraction corresponding to non-protein nitrogen is extracted with trichloroacetic acid (10%), this value decreases to 14-15%. Remarkable differences in the distribution of the protein fractions are observed when two schemes of extraction are assayed. The amino acid analysis shows that this legume has similar or higher amounts of most amino acids than those present in other leguminosae; the calculated chemical score and protein score show that methionine is the first limiting amino acid and tryptophan, the second. The protein efficiency ratio (PER) of thermically-treated flours has the highest value at 30 minutes of treatment (1.15).     

Study and comparison of different drying processes for dehydration of raspberries

The aim of the present study was to evaluate and compare different drying methods (microwave, hot air?+?microwave, and osmotic dehydration?+?microwave) in raspberries (cv. Heritage). A portion of raspberries was pretreated with osmotic dehydration (60°Brix sucrose solution at 20°C for 360?min) and another with hot air drying (HAD) (1.5?m/s air speed at 60°C for 300?min). Pretreated raspberries were then dried by microwave and at three different intensities (3.5, 7.5, and 11?W/g). Physicochemical properties (moisture content, water activity, and drying rate) and quality parameters (optical properties, mechanical properties, antioxidant capacity, and rehydration capacity) of dried raspberries were evaluated. Results showed that the microwave drying (MWD) at 7.5?W/g (50?min and final temperature of 79?±?5.1°C) allowed a high yield of dried raspberries. The combined processes were not efficient to accelerate the decrease of moisture content, due to the low drying rate of the pretreatments. In terms of quality, none of the drying processes allowed a high retention of the antioxidant capacity. However, they allowed an appropriate rehydration performance. The combination of HAD with MWD allowed obtaining a good appearance and desirable texture on the dried product. Thus, this last option seems to be the best among the drying methods tested, but additional studies are required to improve the efficiency of the process and the effect on the antioxidant capacity during drying.     

Influence of Mo doping on the tribological behavior of Ti3AlC2 ceramic at different temperatures

(Ti_0·8Mo_0.2)₃AlC₂ solid solutions were successfully synthesized from Ti, Al, TiC, and Mo powders using the in situ hot-pressing sintering method. The tribological properties of (Ti_0·8Mo_0.2)₃AlC₂ and the reference Ti₃AlC₂ in the temperature range 25–800 °C were evaluated in ambient air with the counterpart of Al₂O₃ balls. The results show that (Ti_0·8Mo_0.2)₃AlC₂ has improved lubricating properties and wear resistance above 400 °C compared with Ti₃AlC₂. This can be contributed to the formation of tribo-oxidation films containing MoO₃ and MoO_3-x. Structural characterization of the tribo-oxidation films was conducted using SEM, EDS, Raman spectroscopy, and XPS to evaluate the effect of Mo doping on the wear mechanisms of Ti₃AlC₂ in detail.     

不同炼焦方式对焦炭质量的影响

采用国内有代表性的焦炉进行配煤炼焦试验,探讨不同炼焦方式对焦炭质量的影响,结果表明,捣固、配型煤、配沥青炼焦均能改善焦炭质量。当入炉煤的挥发分较高、黏结性偏低时,焦炭质量改善的效果较为显著;采用捣固炼焦比配型煤、配沥青炼焦更能有效地改善焦炭的反应性和反应后强度。     

不同熔炼工艺对电熔方镁石的影响

为了提高电熔方镁石品位,合理利用资源,以菱镁矿为原料制备电熔方镁石。研究了不同石墨电极（分别是直流空心电极、直流实心电极、交流空心电极和交流实心电极）对电熔方镁石的影响。通过对电熔方镁石的体积密度、显气孔率、物相组成和显微结构进行分析,结果表明：电熔方镁石坯体在靠近皮砂位置结晶最好,晶体发育比较完整;使用空心电极制备出的电熔方镁石结构致密,晶粒尺寸大。用交流空心电极制备出的电熔方镁石体积密度最大、显气孔率低、晶界平直,形成了较大尺寸的方镁石晶粒。     

Structural and adhesion properties of poly(ethyl 2-cyanoacrylate) post-cured at different temperatures and times

The structure and properties of poly(ethyl 2-cyanoacrylate)s (pECNs) cured at 25?°C during 24?hours, and post-cured at different temperatures (45-90?°C) and times (2-6?hours) were studied. Irrespective of the post-cure conditions, pECN was not fully polymerized and two different structures of different molecular weights and topographies were obtained. The post-cure decreased the shear strength values in joints made with aluminum and ethyl cyanoacrylate due to the decrease in the percentage of higher molecular weight polymeric chains and the formation of new short polymeric chains by unzipping de-polymerization mechanism, both contributed to decrease the mechanical properties. On the other hand, the post-cure changed the morphology of pECN because of nano-spheres were produced by curing at 25?°C which were not present after post-cure at 90?°C.     

The nutritive value of soybean oil meal prepared by the different methods of oil extraction

This article is primarily a review of the literature pertaining to the subject. Solvent extracted, hydraulic, and expeller soybean oil meals all contain, if properly cooked, protein of high biological value, similar to that of milk protein. Solvent extracted meal has a higher percentage of protein. Since expeller and hydraulic meals contain more oil than solvent extracted soybean oil meal, they naturally have a slightly higher vitamin A and D potency, but the amounts of these vitamins contained in any type of soybean meal or even in the whole soybean are not significant. Levine’s assays reveal that solvent process soybean oil meal contains roughly 2.8 I.U. of vitamin B per gram of solids compared to 1.0 I.U. for hydraulic meal. According to results of Cornell experiments, the vitamin G content of soybeans is not materially affected by any of the common methods of processing. Kraybill reports that expeller and hydraulic pressed soybean oils contain more “lecithin” (total phospholipins) than hexane extracted soybean oil. Therefore his results indicate that our domestic solvent extracted meal contains slightly more “lecithin” than expeller meal. “Lecithin” in soybean oil meal may be valuable as an antioxidant to stabilize the vitamin A contained in mixed feeds.     

Influence of spray drying temperatures and storage conditions on physical and functional properties of dried egg white

This study investigated the effect of spray drying inlet temperatures (140, 160 and 180°C) and storage conditions (temperature; 25 and 40°C and storage period; 1 and 2 months) on the physical and functional properties of dried egg white. The results showed that the three inlet temperatures did not affect the color of the spray-dried egg white (SDEW) after drying. However, all SDEWs increased in yellow color after storage at 40°C. The solubility (%) of SDEW and gelling properties including gel hardness and water holding capacity of the gel samples were changed when the dried samples were stored, particularly for SDEW drying at 180°C. The changes in gelling properties of the SDEW were related to a decrease in the enthalpy of protein denaturation, an increase in exposed sulfhydryl (SH) contents, a decrease in the total SH contents and the occurrence of protein aggregation as shown by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern.     

Nutritional value of mung bean (Vigna radiata) as effected by cooking and supplementation

The study was conducted to improve the nutritional value of Mung (Vigna radiata) by supplementation with different kinds of meat. Diets were prepared using raw and cooked Mung and then cooked Mung was supplemented with poultry, mutton and beef at 10, 15, and 20 percent levels. Nutritional value of Mung was determined by chemical analysis as well as by rat assay. Mung had 25 percent protein and minor losses were observed during cooking. It had 1.21 percent lysine which was reduced by 43 percent on cooking. Other amino acids also showed losses during cooking. The Protein Efficiency Ratio (PER) of diet containing Mung was significantly reduced on cooking (1.86 vs 1.40). On the contrary cooking resulted in some improvement of Net Protein utilization (NPU) and True Digestibility (TD) of the Mung based diets. Twenty percent level of different meats showed better results in terms of PER, NPU and TD.     

Influence of blanching treatment and drying methods on the drying characteristics and quality changes of dried sardine (Sardinella gibbosa) during storage

The aim of this study is to examine the drying characteristics of blanched and unblanched sardine during indoor and open sun drying processes. Changes in temperature and relative humidity of the air during drying were recorded. The color, peroxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acid (FFA) content, fatty acid composition, and sensory attributes of dried samples were also evaluated once a month for 5 months of storage. High drying rates were obtained in all samples at the start of drying and then decreased with increasing drying time. The highest drying rate and effective water diffusivity (D_eff) were observed in blanched sardine during open sun drying. Blanching treatment slowed down the FFA progression during product storage but adversely affected the color, PV, and TBARS content as well as sensory properties. Although sardine dried for a longer time under indoor drying conditions, it attained a stable moisture ratio that was lower than in open sun-dried samples. Indoor drying produced a quality stable product with less lipid oxidation and the desired moisture content, higher polyunsaturated fatty acids and sensory properties. Blanching treatment negatively affected the fish quality and is therefore not recommended for commercial sardine drying.     

Chemical composition, amino acid content and nutritive value of the protein of the annatto seed (Bixa orellana, L.)

On several occasions, many Latin American countries have shown interest in the economic potential of industrializing the exploitation of the pigment in Annatto seed (Bixa orellana, L) used as a natural coloring agent in the food industry. Production of the pigment leaves the seed as a by-product, which once characterized chemically and nutritionally, could contribute to a more profitable exploitation of Annatto seed. The main objective of the present study was to obtain information in regard to this matter. The results of chemical analyses of the seed showed a relatively high amount of protein, which fluctuated between 13 and 17%. Crude fiber levels were also high, about 16%; however, more than 50% of this fiber can be eliminated through sifting of the seed flour. This operation also increases protein content. Annatto seeds have a high phosphorus and a low calcium content. Its protein contains adequate levels of tryptophan and lysine, but is low in methionine, isoleucine, leucine, phenylalanine and threonine. The protein quality of Annatto seed flour was about 65% that of casein, which was used as reference protein. Partly responsible for this low biological value are the amino acid deficiencies, mainly that of methionine, and the low digestibility of the protein. The latter was 57% as compared to 94% for casein, a finding which can be attributed to the crude fiber content of Annatto seed flour, since partial elimination of the fiber resulted in an increase in digestibility up to a value of 65%. In order to utilize more effectively this potential feedstuff in combination with other feeds, further studies should confirm the amino acid deficiencies and digestibility of the Annatto seed protein.     

Long-term effect of diesel degradation on polyoxymethylene at different temperatures

Diesel is an important fuel, partly because of the longevity and cleanliness of diesel engines. Often, polymers are in direct contact with diesel and understanding compatibility is critical. Polyoxymethylene (POM) is a thermoplastic used to manufacture automotive fuel pump gears and rotors due to its low coefficient of friction and thermal and dimensional stability. In this study, tensile tests were performed on plain and glass fiber reinforced (POM and POMGF) after immersion in diesel at different temperatures (−10°C, 23°C, and 60°C) for 1000, 2000, 3000, 5000, and 10 000 hour. A mathematical model was developed using data from just three tensile stress-strain curves obtained at two different fluid temperatures and three different immersion times. Model and experimental results show good agreement with one another for all conditions tested.     

不同温度下反硝化除磷污泥特性研究

在低温(15℃)与常温(25℃)条件下,用SBR反应器对反硝化除磷污泥特性进行了系统分析.结果表明.在常温与低温条件下反硝化除磷菌(DPB)污泥均具有较好的沉降性能:总磷质量分数分别为2.3%～3.7%和1.6%～2.1%;DPB占总PAOs的质量分数(R<,DPB>)分别约为77%和51%;VSS/SS分别为76%～88.6%和74%～85.3%.低温下DPB污泥中存在钟虫和少量轮虫等原生动物.低温下DPB污泥系统运行正常,可通过增加污泥浓度和延长反应时间以提高除磷率.