优化碱洗塔操作减少黄油生成

叙述了乙烯装置自开车以来碱洗塔运行的情况,并分析黄油产生的原因及消除黄油应采取的措施。     

螺旋藻多糖铁配合物制备、抗氧化及淋巴细胞增殖活性分析

以三氯化铁为原料,通过络合反应,对螺旋藻多糖(SP)进行结构修饰,制得有机铁化合物〔螺旋藻多糖铁(Ⅲ)配合物SP-Fe(Ⅲ)〕。采用FTIR、DSC、TGA、XRD和SEM对其结构进行了表征,采用DPPH(1,1-二苯基-2-三硝基苯肼)自由基法、羟自由基法等5种方法和MTT(四唑盐)法分析了SP和SP-Fe(Ⅲ)的抗氧化活性和淋巴细胞增殖活性的影响。制备的SP-Fe(Ⅲ)中Fe(Ⅲ)质量分数为16.42%±1.17%。采用5轴蛛网图对SP-Fe(Ⅲ)的抗氧化活性进行了综合评价。结果表明,SP-Fe(Ⅲ)相比SP具有较高的抗氧化活性。在模拟人工胃液消化后,随着消化时间的延长,在pH=6.8的人工肠液中释放出的Fe(Ⅲ)质量分数达到83.64%;在31.25×10–3 g/L的质量浓度下,与SP相比,SP-Fe(Ⅲ)配合物对淋巴细胞增殖提高了44.35%。     

New Insights into the Anti‐Inflammatory and Antioxidant Properties of Nitrated Phospholipids

Nitro‐fatty acids (NO₂‐FA) have been widely studied with regard to their identification, structural characterization, and biological actions. NO₂‐FA could also be present endogenously esterified to phospholipids (PL), and NO₂‐PL were already detected in cardiac mitochondria from diabetic rats and cardiomyoblasts subjected to starvation. However, the biological actions of NO₂‐PL have been overlooked. In this study, we evaluate the antioxidant and anti‐inflammatory potential of the nitrated 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (POPC) formed in vitro by incubation with NO₂BF₄, in a well‐recognized mimetic model of nitroxidative stress. Nitrated POPC showed anti‐radical ability to reduce both 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH^?) (IC₂₀ = 225 ± 4 μg/mL; Trolox equivalent (TE) = 86 ± 6 μmol Trolox/g lipid) and 2,2′‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid radical cation (ABTS^?+) (IC₅₀ = 124 ± 2 μg/mL; TE = 152 ± 9 μmol Trolox/g lipid). Also, higher lag times were achieved in oxygen radical absorbance capacity (ORAC) assay for nitrated POPC, indicating a faster reaction with oxygen‐derived radicals (TE = 1.03 ± 0.22 and TE = 1.30 ± 0.16 mmol Trolox/g lipid for nonmodified and nitrated POPC, respectively). Nitrated POPC showed the ability to inhibit lipid oxidation induced by the hydroxyl radical generated under Fenton reaction conditions, monitored by electrospray ionization (ESI) mass spectrometry (MS) using phosphatidylcholine (PtdCho) liposomes as a model of cell membrane. Nitrated POPC showed anti‐inflammatory potential, as assessed by the inhibition of inducible nitric oxide synthase (iNOS) expression in RAW 264.7 macrophages activated by the Toll‐like receptor 4 (TLR4) agonist lipopolysaccharide (LPS) in a well‐described in vitro model of inflammation. Altogether, this study provides new clues regarding the antioxidant and anti‐inflammatory potential of nitrated POPC, which should be explored in depth.     

The Effect of Phospholipids on Milkfat Crystallization Behavior

Depending on the production method, the fat component in butter can either be in a continuous phase or entrapped by milk fat globule membranes (MFGM). Phospholipids like those present in the MFGM are known to affect milk fat crystallization behavior. This study examines the effect of MFGM phospholipid concentration on butter crystal structure. Regular raw cream was first concentrated to 85% fat via centrifugation to produce a “plastic” cream, and was then blended with anhydrous milk fat (AMF) and skim milk in order to maintain the total fat-to-water ratio while altering the total amount of MFGM in the butter product. Whereas mixtures of AMF and skim milk contained large spherulites that had finer structures as the degree of supercooling was increased, the addition of globular fat (GF) broke up these structures, eventually producing smaller individual needle-like crystals. However, high levels of GF also lead to the coalescence of the aqueous phase, creating large water pockets that adversely affect sensory properties. Thus, the phospholipid concentration in the final butter product must be controlled in order to obtain optimal crystal structure and product quality.     

Preparation and the antioxidant and antibacterial activities of urushiol powders (YPUOH)

Lacquer sap derived from lacquer trees has been widely used in Asian countries for thousands of years as a natural paint and coating material. These natural lacquers exhibit superior barrier properties against oxygen and water, as well as good durability, chemical resistance, mechanical properties, and antibacterial and antioxidant properties. However, they are limited in commercial application due to their high volatility, low drying rate, and allergic reactions. To overcome these limitations, powder-type urushiols (YPUOH), which are essential to provide convenient handling, were successfully prepared using urushiol and different contents of 3-(trimethoxysilyl) propyl methacrylate (TPM). The prepared YPUOH powders were analyzed by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), and antibacterial and antioxidant measurements. The as-prepared YPUOH powders exhibited excellent antibacterial activity against E. coli and S. aureus, good antioxidant activity, and high thermal stability.     

Effect of Different Drying Methods and 24-Month Storage on Water Activity,Rehydration Capacity,and Antioxidants in Boletus edulis Mushrooms

This article evaluates the effect of air drying, freeze drying, and 24-month storage at 4 and 20 ^° C on unblanched and blanched Boletus edulis . Water content and activity were lower in freeze-dried mushrooms than in air-dried mushrooms, whereas rehydration capacity showed the opposite tendency. Drying resulted in substantial losses of the following antioxidants: total flavonoids (4–7%), vitamin C (2–36%), β-carotene (26–32%), and total tocopherols (72–81%); total polyphenols increased during air drying (7–17%) and decreased during freeze drying (5–7%). Antioxidant activity increased 1–33% during drying. Storage led to further changes in the quality of dried mushrooms. After 24 months, no vitamin C or tocopherols were detected, and water content and activity were moderately high.     

Polyphenolic Profile and Antioxidant Activities of Oolong Tea Infusion under Various Steeping Conditions

The phenolic profile and antioxidant activities of oolong tea extract were investigated after tea was steeped in 90 or 100 °C water for 3 or 10 min. The extraction yield increased with increasing temperature and extended steeping time. However, higher temperature and longer time (100 °C water for 10 min) led to loss of phenolics. The aqueous extract of oolong tea (AEOT) at 100 °C for 3 min exhibited the strongest antioxidant activity. The major polyphenolic components of the AEOT were identified as (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCG) and (−)-epicatechin-3-gallate (ECG). The two major catechins (EGC and EGCG) in the tea infusion contributed significantly to the investigated antioxidant activities [i.e., the 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical scavenging and superoxide radical scavenging activities] with high correlation values in r = 0.9486 and 0.9327 for the EGC and r = 0.9592 and 0.8718 for the EGCG, respectively.     

大球盖菇多糖提取工艺、结构表征及生物活性

采用超声辅助离子液体(1-烷基-3-甲基咪唑溴盐,EADS)对大球盖菇多糖进行提取,通过单因素和响应面法优化提取工艺。采用DEAE-100纤维素柱、Sephadex G-100凝胶柱对大球盖菇粗多糖(SRP)纯化,得纯化后均一大球盖菇多糖(SRP-I)。UV、FTIR、GC-MS、XRD、SEM、EDS、刚果红、热重、酸水解、Smith降解、NMR等实验探究SRP-I的结构性质,并评价了SRP-I的体外抗氧化和降糖活性。结果表明,SRP最佳提取工艺为:提取时间106 min,提取温度51 ℃,EADS质量浓度4.3 mg/mL,纤维素酶添加量0.52 g,在此条件下提取率为(32.54±0.12)%;SRP-I是一种具有三螺旋构象的α-D-吡喃构型的中性多糖,表面平整光滑,无定形和晶体共存,热稳定性较好,在550 ℃时残碳率为26.34 %;平均分子量为24.321KDa,主要由岩藻糖(53.31 %)、葡萄糖(43.32 %)和半乳糖(3.37 %)组成,其中岩藻糖主要存在于侧链中,而葡糖糖和半乳糖较均匀的分布在主链和侧链上,主链是以[→3)-Glcp(1→]和[→6)-Galp(1→]的结构组成,同时还存在[→3,6)-Glcp(1→]的支链结构;SRP-I 质量浓度为2.5 mg/mL时,对DPPH自由基、ABTS自由基、羟基自由基清除率分别可达82.54 %、51.62 %、51.57 %,其IC50值分别为0.127 mg/mL、2.438 mg/mL、2.446 mg/mL。对α-淀粉酶和α-葡萄糖甘酶抑制率分别为61.2 %、71.4 %,其IC50值分别为0.97 mg/mL、0.24 mg/mL。     

Investigation of antioxidant activity and lipophilicity parameters of some preservatives

The preservatives have been widely used in food, drugs and cosmetic products to prevent their aging and decay. Antioxidant and antimicrobial activities of some preservatives, such as benzoic acid, sorbic acid and alkyl-parabens, were considered in this work. Study of antioxidant properties of these compounds was carried out by differential pulse voltammetry together with evaluation of their influence on the kinetics of the electrochemical oxygen reduction. Mathematical models of the processes were obtained and their adequacy was estimated using design of experiment methods. As a result, the kinetic parameters of interaction between reactive oxygen species and preservatives were evaluation. Finally, the use of these substances as antimicrobials and antioxidants ensured product stability and safety has been recommended.     

Electron beam-induced mutants of microalgae Arthrospira platensis increased antioxidant activity

Electron beam accelerators are reliable and durable equipments of produce ionizing radiation, and can be used industrially as a means to modify physical, chemical, or biological properties of commercial products. We used electron beam-induced mutagenesis to generate genetic diversity in the industrial strain of the microalgae Arthrospira platensis (A. platensis). A screen of A. platensis cells that were exposed to high energy (0.2 MeV, 1.2 mA) electron beams revealed 2 mutants, EM240 and EM384, that had increased levels of commercially valuable compounds compared to the parental strain of microalgae without the penalty to growth rate that is observed when other methods are used to increase these parameters. The increase in the levels of biologically active compounds, such as phycocyanin, lipids, phenolic compound, flavonoids and antioxidant enzymes (SOD and POD) in mutant cells resulted in enhanced antioxidant activity. Thus, to our knowledge, our study is the first to show that it is feasible to use electron-beam mutagenesis as a means to produce microalgae mutants that can be screened for high productivity of commercially valuable bioactive compounds for use in industrial processes.     

The Effect of Germination on Phenolic Compounds and Antioxidant Activity of Pulses

In this study the changes of phenolic compounds and antioxidant activity of four different pulses namely white bean (Phaseolus vulgaris L), Common vetch (Vicia sativa), Lentil (Lens culinaris) and Chickpea (Cicer arietinum) seeds before and after germination were investigated. Seeds germinated in dark chambers maintained near 100 % relative humidity at 20 °C. Three different solvents namely acetone, hexane and methanol were employed to extract the phenolic compounds present in the seeds and sprouts. Total content of phenolic compounds was measured by the Folin–Ciocalteu method and antioxidant activity determined by the delay in fat oxidation. Different concentrations of extracts (0.02 and 0.1 % w/w) were added to tallow and the stabilities of the treatments were determined by the peroxide value and induction period measurements to evaluate the antioxidant activities. The results indicated that the increases in phenolic content from dormant seed to sprouted seed were significant (P ≤ 0.05) in all the samples. The significant differences between induction periods of tallow treated with sprouted seed extracts were observed (P < 0.05). The results indicated that the greatest increase in stability was obtained when tallow was treated with a 0.1 % concentration of acetone chickpea sprout extract. The pulses' sprout flour or extract might be recommended for use as a source of natural antioxidants in functional foods.