角蛋白酶对羊毛蛋白酶防毡缩整理的促进作用

采用Bacillus subtilis产角蛋白酶与蛋白酶-浴法处理羊毛,研究处理后羊毛织物的毡缩率、减量率、强力、润湿性及纤维直径等指标的变化,测试羊毛和羊毛角蛋白水解液中蛋白多肽的释放速率.结合羊毛的溴Allwǒrden现象,通过SEM观察,考察2种酶协同对蛋白质的降解作用、对羊毛防毡缩性能的影响和对羊毛鳞片的去除效...     

1398中性蛋白酶对羊毛织物防毡缩整理的研究

用1398中性蛋白酶对羊毛织物进行防毡缩整理，对羊毛纤维外层鳞片酶解的不均匀性作了进一步探索，并提出用转谷氨酰胺酶与1398中性蛋白酶同时作用于羊毛织物，增强其断裂强力，降低减量率并进一步提高其防毡缩性能的方案，获得理想效果。     

芬顿试剂法对羊毛织物防毡缩及染色性能的影响

采用芬顿试剂法对羊毛纤维鳞片进行氧化处理,与单用双氧水预处理、蛋白酶处理等常规氧化法进行比较,探讨了芬顿试剂法对羊毛织物防毡缩及染色性能的影响。此外,还讨论了C12H25NaO4S、Fe2+、生物酶及螯合剂EDTA对织物色差ΔE的影响。利用扫描电镜观察被处理羊毛鳞片表层状态,测试了羊毛织物毡缩率、色差、断裂强力。结果表明,芬顿试剂法与常规氧化法相比,对羊毛鳞片具有较强的氧化作用,对羊毛织物防毡缩效果显著,可明显提高织物上染率,织物断裂强力损失率为8.4%,不会影响其服用性能。     

Savinase蛋白酶对羊毛织物的整理

研究了Savinase蛋白酶对羊毛织物的防毡缩效果,以及Savinase蛋白酶对羊毛纤维外层鳞片酶解作用的均匀性问题。尝试将Transglutaminase转移酶与Savinase蛋白酶同时作用于羊毛织物,增强了羊毛织物的强度,降低了减量率,进一步提高了羊毛织物的防毡缩性能。     

羊毛织物酶法与化学法防毡缩整理效果比较

针对现有研究中采用蛋白酶种类、酶活不同以及羊毛织物规格不一致等原因,难以对不同工艺处理后的织物进行直接地防毡缩整理效果比较,故基于羊毛“减法”防毡缩原理,考察了相同规格羊毛织物的酶法(角蛋白酶、蛋白酶、角蛋白酶-蛋白酶复合和DCCA-蛋白酶复合)与化学法(二氯异氰尿酸DCCA、过氧甲酸和KMnO4)防毡缩整理效果。结果表明:羊毛织物经蛋白酶单独处理时的防毡缩效果较好,润湿性明显提高;蛋白酶分别与DCCA和角蛋白酶复合处理羊毛织物时,纤维鳞片层被进一步破坏,织物的防毡缩效果更好。     

羊毛生物法防毡缩技术的研究

采用天然生物材料壳聚糖和生物酶对羊毛织物进行防毡缩处理，通过对脂肪酶、蛋白酶处理浓度、不同处理方法比较试验，探讨了一种纯生物羊毛防毡缩处理技术。研究表明，脂肪酶可有效去除羊毛表面的类脂层；壳聚糖先于蛋白酶处理，可对羊毛起到一定的保护作用；经适当的蛋白酶处理后，羊毛的鳞片尖角变钝，使羊毛具有一定的防毡缩性能。     

嗜热酶在羊毛减量处理中的作用

针对羊毛的特殊结构与酶对其作用的机理,研究嗜热酶在羊毛减量处理中的作用.通过对处理后织物减量率、强力与防毡缩性能的测试,并结合扫描电镜分析,发现在较高温度下用嗜热酶处理羊毛,无需前处理即有较高的减量效率,可对羊毛的鳞片层进行有效的剥蚀,且对皮质层的损伤较小,处理后织物的强力损失小,防毡缩性能有所提高.     

前处理对毛织物防毡缩整理的影响

为了改善羊毛织物毡缩性能,运用不同前处理与蛋白酶结合的方法对羊毛织物进行表面改性,探讨整理后织物毡缩性能和强力的变化,从而确定最佳前处理方案。应用SEM研究不同前处理、前处理与蛋白酶共同整理对织物表面形貌的影响,探讨不同前处理对羊毛用蛋白酶处理防毡缩性能的影响。研究结果表明:仅用蛋白酶处理,羊毛织物毡缩率仅下降到11.4%,很难达到羊毛防毡缩的目的,LTP前处理对于其后进行的蛋白酶防毡缩处理效果具有显著的影响,毡缩率下降到5.6%,达到了国际羊毛局防毡缩标准。     

Preparation of modified protease and its application on antifeiting finishing of wool

针对生物酶法处理羊毛防毡缩易出现的强力损伤问题,采用对蛋白酶进行聚合物接枝改性的方法增大蛋白酶体积而限制其向纤维内部扩散,使其对羊毛鳞片的分解停留在表层,降低酶分解作用对羊毛的强力损伤.将聚合物Eudragit L100经碳二亚胺活化后,通过共价键对碱性蛋白酶Esperase 8.0L进行接枝,形成改性蛋白酶Eudragit-Esperase(EE),使得Esperase 8.0L蛋白酶的分子质量从4.1～6.5 kDa增大至45 kDa以上,经分析测试,其基本达到改性要求.羊毛织物经改性蛋白酶EE处理后,与用蛋白酶Esperase 8.0L处理织物的性能相比,织物的失重率降低21.90％,拉伸断裂强力提高13.10％,说明EE可显著降低羊毛纤维的损伤.同时,经EE处理后羊毛织物的面积毡缩率从原毛织物的8.12％降至0.89％,表明改性蛋白酶EE处理赋予织物良好的防毡缩性能.     

TG酶在修复羊毛损伤中的应用

为了减少羊毛蛋白酶防毡缩造成的损伤,应用TG酶对羊毛织物进行整理,研究TG酶对羊毛损伤的修复作用。结果表明：TG 酶可以修复化学预处理和蛋白酶防毡缩处理对羊毛造成的损伤,使羊毛织物强力增加,碱溶度下降。TG酶可以催化羊毛纤维蛋白质分子内的交联。羊毛的蛋白酶/TG酶联合防毡缩的最佳工艺为: 蛋白酶Sav用量1%（o.w.f.）, 蛋白酶Sav作用时间30min,pH值8~9;TG酶用量2%（o.w.f.）,TG酶作用时间50min,pH值6~7;浴比均为20:1,温度均为50℃,该工艺处理后羊毛织物的毡缩率为2.93%, 强力380.4N,强力损伤控制在7.4%。     

Element concentrations in shell of Pinctada margaritifera from French Polynesia and evaluation for using as a food supplement

Element concentrations in shell of Pinctada margaritifera (black-lip pearl oyster) from Manihi, French Polynesia, were measured with Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES). The respective average concentrations were: calcium (Ca) 396.4 mg/g, sodium (Na) 5.536 mg/g, magnesium (Mg) 2.136 mg/g, strontium (Sr) 890.6 ppm, iron (Fe) 67.89 ppm, aluminum (Al) 45.74 ppm, phosphorus (P) 27.19 ppm, boron (B) 12.17 ppm, manganese (Mn) 2.308 ppm, copper (Cu) 1.050 ppm, zinc (Zn) 0.7180 ppm; and nickel (Ni), chromium (Cr), mercury (Hg), arsenic (As), cadmium (Cd), lead (Pb), and vanadium (V) were below detection limits with ICP-AES.     

Effects of extracts of spices on rumen methanogenesis,enzyme activities and fermentation of feeds in vitro

BACKGROUND: An experiment was conducted to study the effects of boiling water, methanol and ethanol extracts (0, 0.25 and 0.50 mL) of seeds of Foeniculum vulgare (fennel), flower buds of Syzygium aromaticum (clove), bulbs of Allium sativum (garlic), bulbs of Allium cepa (onion) and roots of Zingiber officinalis (ginger) on rumen methanogenesis, fibrolytic enzyme activities and fermentation characteristics in vitro. RESULTS: Ethanol and methanol extracts of fennel, clove and garlic at 0.50 mL and clove at 0.25 mL inhibited (P < 0.05) methane production. Carboxymethylcellulase activity was reduced (P < 0.05) by ethanol and methanol extracts (0.50 mL) of fennel and clove (0.25 and 0.50 mL). The extracts of clove reduced (0.25 and 0.50 mL) xylanase and acetylesterase activities, and the fennel extract (0.50 mL) reduced (P < 0.05) xylanase activity. However, the extracts of garlic (0.50 mL) increased (P < 0.05) acetylesterase activity. Concentrations of volatile fatty acids were reduced (P < 0.05) by the extracts of garlic and onion. The extracts of garlic caused a decrease (P < 0.05) in acetate:propionate ratio (A:P) at 0.50 mL, whereas A:P was increased (P < 0.05) by the inclusion of 0.50 mL extracts of clove. Methanol and ethanol extracts of clove decreased (P < 0.05) in vitro organic matter degradability. Extracts (0.50 mL) of clove decreased (P < 0.05) the numbers of total protozoa, small entodiniomorphs and holotrichs, whereas extracts of onion, ginger and garlic enhanced (P < 0.05) protozoal numbers (both entodiniomorphs and holotrichs). CONCLUSION: Ethanol and methanol extracts of fennel and garlic have potential to inhibit rumen methanogenesis without adversely affecting rumen fermentation. Copyright © 2009 Society of Chemical Industry     

Chemical characterization of the oligosaccharides in Bactrian camel (Camelus bactrianus) milk and colostrum

Bactrian camel milk and colostrum are commonly used as foods in Mongolia, whose people believe that these products promote human health. It has been hypothesized that milk oligosaccharides are biologically significant components of human milk, acting as receptor analogs that inhibit the attachment of pathogenic microorganisms to the colonic mucosa, and as prebiotics, which stimulate the growth of bifidobacteria within the infant colon. To evaluate their biological significance, we studied the oligosaccharides present in samples of Bactrian camel milk and colostrum. Using ¹H-nuclear magnetic resonance spectroscopy, we identified and characterized the following oligosaccharides of camel colostrum: Gal(β1–4)[Fuc(α1–3)]Glc (3-fucosyllactose), Gal(β1–3)Gal(β1–4)Glc (3′-galactosyllactose), Gal(β1–6)Gal(β1–4)Glc (6′-galactosyllactose), Neu5Ac(α2–3)Gal(β1–4)Glc (3′-sialyllactose), Neu5Ac(α2–6)Gal(β1–4)Glc (6′-sialyllactose), Neu5Ac(α2–3)Gal(β1–3)Gal(β1–4)Glc (sialyl-3′-galactosyllactose), Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (sialyllacto-N-tetraose c), Neu5Ac(α2–3)Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyllacto-N-novopentaose a), Gal(β1–3)[Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyllacto-N-novopentaose b); and Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (monosialyllacto-N-neohexaose). The oligosaccharides in the mature camel milk were characterized as 3′-galactosyllactose, Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novopentaose I), and 3′-sialyllactose.     

Antimicrobial resistant genes associated with Salmonella from retail meats and street foods

We examined the antimicrobial resistance of Salmonella isolates from 300 meat products (raw beef, chicken meat and street foods). A total of 88 non-duplicate Salmonella from 66 (22.0%) retail meat and 22 (7.5%) street food samples were recovered and 11 serovars were identified. Among the 88 Salmonella isolates, the highest resistance was to tetracycline (73.8%), followed by sulfonamide (63.6%), streptomycin (57.9%), nalidixic acid (44.3%), trimethoprim–sulfamethoxazole (19.3%), ampicillin (17.0%), chloramphenicol (10.2%), cephalotin (8.0%), kanamycin (6.8%), ciprofloxacin (2.2%) gentamycin (2.2%), cefoxitin (2.2%), amoxicillin–clavulanate (1.0%) and amikacin (1.0%). Sixty-seven percent of the isolates (59/88) were multidrug resistant (MDR). Ten out of 17 resistance genes (bla_TEM-1, strA, strB, aadA, sulI, sulII, tetA, tetB, floR, cmlA) were detected. Twelve of the 59 MDR Salmonella isolates from serovars Typhimurium (6), Newport (3), Agona (1), Albany (1) and Weltevreden (1) had class 1 integrons. The gene cassettes identified were dfrA1, dfrV, dfrA12, aadA2, sul1 genes and an open reading frame orfC of unknown function. Four integron-positive isolates could transfer resistance phenotypes to the recipient strain, E. coli J53 via conjugation. These data revealed that the Salmonella isolates recovered from the retail meats and cooked street foods were resistant to multiple antimicrobials, which can be transmitted to humans through food products. The occurrence of mobile genetic elements such as integrons reiterates the roles of food of animal origins as a reservoir of MDR Salmonella.     

Relationship between the structure,physicochemical properties and in vitro digestibility of rice starches with different amylose contents

The in vitro digestibility and molecular and crystalline structures of rice starches (Long-grain, Arborio, Calrose, and Glutinous) differing in amylose content were investigated and the relationship between the structure and in vitro digestibility of starch was studied. Long-grain showed the highest amylose content (27.2%), whereas Glutinous showed the lowest amylose content (4.2%). Long-grain had the highest average amylopectin branch chain length (18.8) and proportion (8.7%) of long branch chains (DP ≥ 37), and the lowest proportion (26.9%) of short branch chains (DP 6–12). Among the non-waxy rice starches (Long-grain, Arborio, and Calrose), Calrose had the lowest average chain length (17.7) and the lowest proportion (7.1%) of long branch chains (DP ≥ 37). The relative crystallinity of rice starch followed the order: Glutinous (33.5%) > Calrose (31.4%) > Arborio (31.0%) > Long-grain (29.9%). Long-grain had the highest gelatinization temperature and the lowest gelatinization temperature range, whereas Glutinous showed the highest gelatinization temperature range and gelatinization enthalpy. Arborio had the highest melting enthalpy for amylose–lipid complex among the tested rice starches. Pasting temperature, setback, and final viscosity increased with increasing amylose content, whereas the peak viscosity and breakdown showed negative correlations with amylose content. The rapidly digestible starch (RDS) content of the tested rice starches followed the order: Glutinous (71.4%) > Calrose (52.2%) > Arborio (48.4%) > Long-grain (39.4%). Contrary to this, the slowly digestible starch (SDS) and resistant starch (RS) contents showed an opposite trend compared to RDS. Digestibility (RDS, SDS, and RS) of the rice starches was significantly correlated (p ≤ 0.05) with amylose content, proportions of DP 6–12 and DP 13–24, relative crystallinity, intensity ratio (of 1047 cm⁻¹ to 1022 cm⁻¹ from Fourier transform infrared spectroscopy), swelling factor, amylose leaching, onset temperature of gelatinization, gelatinization temperature range, gelatinization enthalpy, pasting temperature, peak viscosity, breakdown, setback, and final viscosity.     

Antimicrobial resistance and co-selection phenomenon in Listeria spp. recovered from food and food production environments

Antimicrobial resistance (AMR), co-selection phenomenon, and the relationship between reduced susceptibility (RSC) to ciprofloxacin (CIP) and resistance to other antimicrobials in Listeria spp. (n = 103) recovered from food processing environments (FPE) and food were investigated. Resistance of Listeria monocytogenes and other listeriae, respectively, to cefoxitin (FOX; 98% vs. 88%), CIP (7% vs. 4%), clindamycin (CLI; 33% vs. 59%) and tetracycline (6% vs. 8%) was observed, as was RSC to CIP (67% vs. 57%) and CLI (65% vs. 41%). L. monocytogenes also possessed RSC to linezolid (LZD; 6%), rifampicin (2%) and streptomycin (6%), with other listeriae displaying RSC to chloramphenicol (4%). L. monocytogenes serotype 1/2a (90%) isolates were more frequently resistant or possessed RSC to CIP compared to serotype 4b (55%) (p = 0.015). When eight strains were experimentally adapted to high concentrations of CIP, co-selection occurred as MICs to benzalkonium chloride (BAC) increased (n = 5), gentamicin MICs remained the same (n = 6) or increased 2-fold (n = 2), and led to RSC to LZD (n = 1) and resistance to CLI (n = 8). Overall, levels of resistance/RSC to CIP in food chain isolates, particularly 1/2a, are concerning. Further, reduced sensitivity to disparate antimicrobials following CIP exposure highlights the need for increased knowledge of co-selection phenomenon linked with antimicrobial agents.     

Lipids from cephalothorax and hepatopancreas of Pacific white shrimp (Litopenaeus vannamei): Compositions and deterioration as affected by iced storage

Lipids from cephalothorax and hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) stored in ice for up to 6 days were extracted and characterised. The extraction yields of lipids from hepatopancreas (10.65–12.64%) were higher than those from cephalothorax (2.59–2.88%). However, no changes in the extraction yield were observed during the storage (p > 0.05). The carotenoid contents of lipids from cephalothorax and hepatopancreas slightly increased within the first 2 and 4 days of iced storage (p < 0.05), respectively, but decreased thereafter (p < 0.05). With increasing storage time, a progressive formation of hydroperoxide was found as evidenced by the increase in the absorbance band at 3600–3200 cm⁻¹ in Fourier transform infrared (FTIR) spectra, and increased peroxide values (PVs) (p < 0.05). The increases in thiobarbituric acid reactive substances (TBARS), p-anisidine value (AnV) and free fatty acid (FFA) content of lipids were noticeable when iced storage time increased (p < 0.05). Those changes indicated that lipid oxidation and hydrolysis occurred in both samples. Phospholipids (PL) were the major components in lipids from cephalothorax (82.51% of total lipids). Nevertheless, lipids from hepatopancreas contained triglyceride (TG) and PL as the dominant components (45.35% and 38.03% of total lipids, respectively). A decrease in the TG content with a concomitant increase in free fatty acid was observed at the end of storage (day 6) (p < 0.05). Decreases in unsaturated fatty acids, especially eicosapentaenoic acid (EPA; C20:5(n-3)) and docosahexaenoic acid (DHA; C22:6(n-3)) were noticeable at day 6 of storage (p < 0.05). Thus, the extended storage time resulted in the enhanced deterioration of extracted lipids.     

Traceability of olive oil based on volatiles pattern and multivariate analysis

An automated head-space solid-phase microextraction (HS-SPME)-based sampling procedure, coupled to gas chromatography–ion trap mass spectrometry (GC–ITMS), was developed and employed for fast characterisation of olive oil volatiles. In total, 914 samples were collected, over three production seasons, in north-western Italy—Liguria (n = 210) and other regions—in addition to the rest of Italy, Spain, France, Greece, Cyprus, and Turkey (n = 704) with the aim to distinguish, based on analytical (profiling) data, the olive oils labelled as “Ligurian” (protected denomination of origin region, PDO) from all the others (“non-Ligurian”). For the chemometric analysis, linear discriminant analysis (LDA) and artificial neural networks with multilayer perceptrons (ANN-MLP) were tested. Employing LDA, somewhat lower recognition (81.4%) and prediction (61.7%) abilities were obtained. The classification model was significantly improved using ANN-MLP. Under these conditions, the recognition (90.1%) and prediction (81.1%) abilities were achieved. The diagnostic value of the data obtained by one-dimensional GC–ITMS were compared with those generated by two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS), allowing a comprehensive analysis of olive oil volatiles.     

Novel Approach of Using Nutraceutic‐Directed Caloric Antioxidant Density and Ion‐Ratio for Evaluating Fruit's Health Quality

Seven kinds of indigenous fruits and five imported fruits were compared for their “health quality.” Methods including the calorific, antioxidant, and ion ratios were carried out. Results indicated the order of content (in mg/100g) was: Ca²⁺, Murcott orange (218.2) > Kiwifruit (200.0) > pineapple (138.5) > Golden kiwi (117.6); Mg²⁺, Pitaya (192.2), banana (88.0), Kiwifruit (63.4), and Golden kiwi (58.4); Zn²⁺, Pitaya (19.53) > pear (10.8) > Kiwifruit (6.09) > Irwin mango (4.58). Cu²⁺, Kiwifruit (0.70) > Red globe grape (0.67) > Golden kiwi (0.65) > Irwin mango (0.42) ≈ Pitaya (0.40). In terms of ion ratio, Pitaya showed Zn²⁺/Cu²⁺ (48.8), Mg²⁺/Ca²⁺ (6.7) and uniquely possessed selenium 0.002 mg/100 g; for pear, Zn²⁺/Cu²⁺ = 37.2, while Kyoho grape, Red globe grape, and Golden kiwi revealed extremely high Fe²⁺/(Co²⁺+Ni²⁺) ratios. On the other hands, Irwin mango and Pitaya astonishingly contained huge amount of inositol, reaching 3523.2 mg/100 g and 1998.7 mg/100 g, respectively. To evaluate the “health quality” of fruits, an overall ranking method by combining (a) the Function‐directed Caloric Antioxidant Density (CAD) and (b) the ion ratio was developed. The finalized ranking of these selected fruits was: Pitaya > cherry > Irwin mango > Murcott orange = pineapple > banana > Golden kiwi > pear > Kiwifruit > Red globe grape > apple > Kyoho grape. Conclusively, this evaluation method is novel, contemporary and scientific, which could more clearly assess the “health quality” of fruits in view of nutritional, calorific, and antioxidant balance.     

Lipid components,fatty acids and triacylglycerol molecular species of black and red rices

Extracted lipids obtained from black and red rices were analysed by high-performance liquid chromatography (HPLC), for endogenous tocochromanols. The molecular species and fatty acid (FA) distribution of triacylglycerols (TAG) isolated from these total lipids were analysed by a combination of AgNO₃ thin-layer chromatography (TLC) and gas chromatography (GC), and were investigated in relation to the content of endogenous tocochromanols. With a few exceptions, the predominant tocols were γ-tocotrienol and α-tocopherol, followed by α-tocotrienol (red) and γ-tocopherol (black) with much smaller amounts of β-, δ-tocopherols and δ-tocotrienol. The lipids of these rices were comprised mainly of TAG (76.4–80.5%), free FA (7.2–9.8%), and phospholipids (3.5–3.6%), whilst other components were present in minor proportions (0.1–4.1%). The principal FA components were palmitic (16:0), oleic (18:1n − 9) and linoleic (18:2n − 6) acids. Fifteen different TAG molecular species were detected and quantified by successive applications of AgNO₃-TLC and GC. The major TAG components were S₂M (7.0–7.8%), SM₂ (12.6–12.9%), M₃ (15.7–16.5%), SMD (23.5–23.7%), SD₂ (5.7–5.8%), M₂D (9.3–9.8%), MD₂ (8.1–8.6%) and D₃ (5.8–7.4%) (where S, M, D, and T denote a saturated FA, a monene, a diene, and a triene, respectively). The results suggested that these rice lipids contain large amounts of nutraceuticals with proven positive health effects.