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收稿日期：2018－07－24；修回日期：2019－02－21作者简介：黄小雪（1996），女，硕士研究生，研究方向为粮食、油脂及植物蛋白（E-mail ）846507614@qq．com 。
通信作者：胡传荣，副教授，硕士生导师，博士（E-mail ）hcr305@163．com 。
油脂加工4种提取工艺橡胶籽油的品质比较研究黄小雪1，曾仕林1，郭雄1，何东平1，2，胡传荣1，2（1．武汉轻工大学食品科学与工程学院，武汉430023；2．国家粮食局粮油资源综合开发工程技术研究中心，武汉430023）摘要：以橡胶籽仁为原料，采用压榨法、浸出法、超声波辅助溶剂法和水酶法制备橡胶籽油。
比较不同提取工艺的油脂提取率、理化性质及脂肪酸组成。
结果表明：超声波辅助溶剂法油脂提取率最高，水酶法的最低；水酶法得到的橡胶籽油的水分及挥发物含量较高；浸出法所得橡胶籽油的酸价最高，压榨法的最低；压榨法橡胶籽油过氧化值最高，水酶法的最低；4种提取工艺所得橡胶籽油的脂肪酸组成基本相同。
关键词：橡胶籽油；提取工艺；理化性质；脂肪酸组成；品质比较中图分类号：TS224；TQ646文献标识码：A文章编号：1003－7969（2019）06－0006－04Quality comparison of rubber seed oils by four kinds of extraction processesHUANG Xiaoxue 1，ZENG Shilin 1，GUO Xiong 1，HE Dongping 1，2，HU Chuanrong 1，2（1．School of Food Science and Engineering ，Wuhan Polytechnic University ，Wuhan 430023，China ；2．Grain and Oil Ｒesources Comprehensive Exploitation and Engineering Technology Ｒesearch Center ofState Administration of Grain ，Wuhan 430023，China ）Abstract ：Ｒubber seed oil was separately extracted from rubber seed by pressing method ，leaching meth-od ，ultrasound －assisted solvent method and aqueous enzymatic method．The oil extraction rates ，physi-cochemical properties and fatty acid compositions of rubber seed oils obtained by different processes were compared．The results showed that the ultrasound －assisted solvent method had the highest oil extraction rate ，while that of aqueous enzymatic method was the lowest．The content of water and volatile matter in the oil obtained by aqueous enzymatic method was higher．The leached rubber seed oil had the highest acid value ，while that of pressed rubber seed oil was the lowest．The peroxide value of pressed rubber seed oil was the highest ，while that of aqueous enzymatic extracted oil was the lowest．The fatty acid com-positions of the four rubber seed oils were basically the same．Key words ：rubber seed oil ；extraction process ；physicochemical property ；fatty acid composition ；quali-ty comparison橡胶籽油是传统食用油之一，在我国的海南岛、云南西双版纳等地有长期食用的历史［1］。
·木质素的羟基化改性·木质素羟基化改性及其在聚氨酯合成中的应用靳汇奇贾文超盛雪茹牛梅红石海强*（大连工业大学轻工与化学工程学院/辽宁省生物质与化学重点实验室，辽宁大连，116034）摘要：工业木质素主要来源于制浆和纤维素乙醇生物精炼的副产物，产量巨大；且木质素具有替代多元醇合成聚氨酯材料的应用潜力。
对木质素进行羟基化改性，可以控制木质素分子质量和增加羟基含量，从而提高木质素的反应活性和在合成体系中的相容性，减少木质素在聚氨酯中的聚集，增加聚氨酯材料的微观均匀性，从而增强聚氨酯材料的机械性能；同时还可能赋予聚氨酯抗紫外、吸油、可降解等性能。
本文对木质素基本理化性质进行简要介绍，重点介绍了目前国内外木质素羟基化改性方法的研究进展；最后探讨了木质素基聚氨酯合成领域的研究和应用前景。
关键词：木质素；羟基化；聚氨酯；改性；机械性能中图分类号：TS721；O636.2文献标识码：ADOI ：10.11980/j.issn.0254-508X.2021.10.016Hydroxylation of Lignin and Its Application in Synthesis of PolyurethaneJIN Huiqi JIA Wenchao SHENG Xueru NIU Meihong SHI Haiqiang *（School of Light Industry and Chemical Engineering/Key Lab of Biomass and Chemistry of Liaoning Province ，Dalian Polytechnic University ，Dalian ，Liaoning Province ，116034）（*E -mail ：Shihq@ ）Abstract ：Industrial lignin with huge output was mainly derived from the by -products of pulping and cellulosic ethanol biorefinery ，and it had the potential to replace polyol to synthetic polyurethane materials.The hydroxylation of lignin could control the molecular weight and in⁃crease the hydroxyl content of lignin ，improving the reactivity of lignin and its compatibility in the synthesis system.It also could reduce the aggregation of lignin in the polyurethane ，increase the micro -uniformity of the polyurethane materials to enhance the mechanical properties of the polyurethane materials.At the same time ，it could also give polyurethane materials anti -ultraviolet ，oil absorption ，degradable and otherproperties.The basic physicochemical properties of lignin were briefly introduced ，and the current research progress of lignin hydroxylationmethods at home and abroad were also introduced.The research and application prospects in the field of synthesis of lignin -based polyure⁃thane materials were discussed.Key words ：lignin ；hydroxylation ；polyurethane ；modification ；mechanical properties木质素是自然界储量第二大的天然高分子化合物，在植物细胞壁中，木质素与纤维素和半纤维素结合在一起为细胞提供支撑[1]。
不同处理与干燥方式对黄瓜脆片理化特性和抗氧化性的比较王浩，祖正梅，程晨霞，张怀震，杨绍兰*（青岛农业大学园艺学院，山东青岛 266109）摘要：该论文以黄瓜为材料，对黄瓜切片进行蒸汽或烫漂预处理，通过空气炸锅、热风干燥、真空冷冻三种干燥方式对预处理后的黄瓜进行干燥处理。
测定黄瓜脆片的硬度、色泽、复水性、电子鼻、叶绿素、以及抗氧化性等生理指标，探究不同预处理以及不同干燥方式对黄瓜脆片理化特性和抗氧化性的影响。
结果显示，未处理冷冻干燥的黄瓜脆片硬度最低，为0.22 N；烫漂后再进行冷冻干燥的黄瓜脆片的复水率、叶绿素含量均为最高，分别为13.37%和1.85 mg/g；空气炸锅和热风干燥处理的样品色泽较深，容易褐化，但预处理中烫漂可以较好的维持黄瓜脆片色泽；电子鼻的LDA分析能够较好区分不同干燥方式的黄瓜脆片；未处理冷冻干燥的黄瓜脆片抗氧化能力最强，DPPH·清除率和O2-·清除率分别为66.30%和46.12%。
因此，预处理烫漂后可以更好的维持黄瓜脆片的颜色特性，但抗氧化活性更低。
进行冷冻干燥的黄瓜脆片更好的维持了黄瓜的颜色特性，也提高了营养价值，但其制作脆片的成本也更高。
关键词：黄瓜脆片；热风干燥；冷冻干燥；空气炸锅；抗氧化性文章编号：1673-9078(2024)04-113-120 DOI: 10.13982/j.mfst.1673-9078.2024.4.0478Comparison of Different Treatments and Drying Methods on the Physicochemical Properties and Antioxidant Activity of Cucumber ChipsW ANG Hao, ZU Zhengmei, CHENG Chenxia, ZHANG Huaizhen, YANG Shaolan*(College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China) Abstract: Cucumber slices were subjected to steam blanching or hot water blanching pretreatment, followed by drying using three different methods: hot air frying, hot air drying, and vacuum freeze-drying. The hardness, color, rehydration, electronic nose, chlorophyll, antioxidant activity, and other physiological indices of cucumber chips were determined to explore the effects of different pretreatment and drying methods on the physicochemical properties and antioxidant activity of cucumber chips. The results showed that the hardness of unpretreated freeze-dried cucumber chips was the lowest at0.22 N. After blanching and freeze-drying, the rehydration rate and chlorophyll content of cucumber chips were the highest引文格式：王浩,祖正梅,程晨霞,等.不同处理与干燥方式对黄瓜脆片理化特性和抗氧化性的比较[J] .现代食品科技,2024, 40(4):113-120.WANG Hao, ZU Zhengmei, CHENG Chenxia, et al. Comparison of different treatments and drying methods on the physicochemical properties and antioxidant activity of cucumber chips [J] . Modern Food Science and Technology, 2024, 40(4): 113-120.收稿日期：2023-04-21基金项目：山东省蔬菜产业技术体系（SDAIT-05）作者简介：王浩（2000-），男，在读硕士生，研究方向：果蔬采后生理与分子生物学，E-mail：通讯作者：杨绍兰（1978-），女，博士，教授，研究方向：果蔬采后生理与分子生物学，E-mail：113黄瓜（Cucumis sativus）属葫芦科一年生攀援草本植物，又名胡瓜、吊瓜等。
刺梨发酵乳的制备及其理化性质杨曦澜，董洁怡，刘佳玥，刘冬梅*（华南理工大学食品科学与工程学院，广东广州510640）摘要：刺梨含有丰富的多糖和维生素C等营养成分以及超氧化物歧化酶（SOD），具有降低慢性疾病风险及发病率的潜力。
该研究选用保加利亚乳杆菌德氏乳杆菌DMLD-H1（Lactobacillus delbrueckii DMLD-H1，简称H1）和嗜热链球菌DMST-H2（Streptococcus thermophilus DMST-H2，简称H2）为发酵剂菌株，通过优化菌种比例、接种量和刺梨汁添加量，确定刺梨发酵乳最佳发酵工艺，并与商业菌种发酵的发酵乳的各项理化性质进行比较。
实验表明，最佳的刺梨发酵乳发酵条件为：菌种比例为H1:H2=1:2，接种量为1.0×107 CFU/mL，刺梨添加量为0.06 g/mL。
在此条件下发酵所得的刺梨发酵乳pH值为4.47，酸度为76.78 °T，持水力为32.94%，其中分离出11种挥发性物质，蛋白质相对分子质量主要分布在22~38 ku，后酸化4周后发酵乳的pH值降低至3.89，活菌数含量为1.1×108 CFU/mL。
对比商业发酵乳发现，刺梨发酵乳能够抑制发酵乳的后酸化作用，提高持水力，以及提升发酵乳中的酪蛋白含量；然而，刺梨可能会影响发酵乳中原本的风味物质。
该研究为一种新型的刺梨发酵乳的开发提供理论依据，为新型功能性发酵乳的研发提供参考。
关键词：刺梨；发酵乳；保加利亚乳杆菌；嗜热链球菌文章编号：1673-9078(2024)03-153-162 DOI: 10.13982/j.mfst.1673-9078.2024.3.0411Preparation and Physicochemical Properties of Roxburgh rose YogurtYANG Xilan, DONG Jieyi, LIU Jiayue, LIU Dongmei*(School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China) Abstract:Roxburgh rose is rich in nutrients such as polysaccharides and vitamin C as well as superoxide dismutase (SOD), and has the potential to reduce the risk and incidence of chronic diseases. In this study, Lactobacillus delbrueckii DMLD-H1 (H1) and Streptococcus thermophilus DMST-H2 (H2) were selected as the fermentation starters. By optimising the strain ratio, inoculation amount and the addition amount of Roxburgh rose juice, the optimal fermentation process for preparing Roxburgh rose yogurt was established. The physicochemical properties of the resulting Roxburgh rose yogurt were then compared with those of the yogurt produced using commercial strains. The results showed that the optimal fermentation conditions for Roxburgh rose yogurt were as follows: H1:H2=1:2; inoculation amount, 1.0×107 CFU/mL; addition amount of Roxburgh rose juice, 0.06 g/mL. The pH value of the Roxburgh rose yogurt obtained under such conditions was 4.47, with its acidity being 76.78 °T, and the water-holding capacity being 32.94%. From such a yoghurt, 11 volatile substances were isolated, and the relative molecular masses of proteins were mainly in the range of 22~38 ku. The pH value of the yogurt 引文格式：杨曦澜,董洁怡,刘佳玥,等.刺梨发酵乳的制备及其理化性质[J] .现代食品科技,2024,40(3):153-162.YANG Xilan, DONG Jieyi, LIU Jiayue, et al. Preparation and physicochemical properties of Roxburgh rose yogurt [J] .Modern Food Science and Technology, 2024, 40(3): 153-162.收稿日期：2023-04-06基金项目：广州市科技计划项目（20212100007；201903010015）；国家级大学生创新创业训练项目（202210561135）作者简介：杨曦澜（2001-），女，在读本科生，研究方向：食品微生物学利用和控制，E-mail：通讯作者：刘冬梅（1972-），女，博士，教授，研究方向：食品微生物的利用与控制研究，E-mail：153decreased to 3.89 and the viable bacterial count was 1.1×108 CFU/mL after 4 weeks of post-acidification. After comparison with the commercial yogurt, it was found that the Roxburgh rose yogurt was able to inhibit yoghurt’s post-acidification, improve the water-holding capacity, and increase the casein protein content of the yogurt; however, the Roxburgh rose may affect the original flavour substances in the yogurt. The study provides a theoretical basis for the development of a new type of Roxburgh rose yogurt and a reference for the development of new functional yogurts.Key words:Roxburgh rose; yogurt; Streptococcus thermophilus; Lactobacillus delbrueckii刺梨是我国西南和中南部山区广泛种植的重要农作物，中国刺梨的年产量约为2 000~3 000 t[1] 。
不同植被类型对土壤物理及化学性质的影响--以挂墩杉竹林和茶园下发育的黄壤为例郭湘宇;陈松林【摘要】The difference of vegetation types has a great impact on soil development, the paper takes yellow soil developed in Guadun of Wuyishan National Natural Reserve as an example, and makes a physicochemical property comparison be-tween different types of yellow soils partly developed in cunninghamia lanceolata forests and tea plantation in the same cli-mate, rock and topographical conditions through field observation and laboratory experiments. In the end, the paper comes to conclusion that the difference of vegetation types is the main factor that causes the differences of physicochemical proper-ty such as soil color, texture, structure, organic matter content, pH, etc, and reveal the effects of different vegetation condi-tions on soil development.%不同植被类型对于土壤的理化性质有重要影响，文章以武夷山自然保护区挂墩发育的黄壤为例，在野外观察、室内实验基础上，将相同气候、母岩、地形条件的杉竹林和茶园下发育的黄壤进行理化性质的比较，得出植被类型的不同是导致土壤结构、颜色、质地、pH值、有机质含量等一系列理化性质差异的原因，揭示不同的植被条件对土壤物理及化学性质的影响。
Journal of Crystal Growth 235(2002)471–481Stabilization of a metastable polymorph of sulfamerazine bystructurally related additivesChong-Hui Gu a,c ,Koustuv Chatterjee a ,Victor Young Jr.b ,David J.W.Grant a,*aDepartment of Pharmaceutics,College of Pharmacy,University of Minnesota,Weaver-Densford Hall,308Harvard St.S.E.,Minneapolis,MN 55455-0343,USAbDepartment of Chemistry,University of Minnesota,207Pleasant St.S.E.,Minneapolis,MN 55455,USAcBristol-Myers Squibb Co.,1Squibb Drive,P.O.191,New Brunswick,NJ 08903,USAReceived 30April 2001;accepted 8October 2001Communicated by A.A.ChernovAbstractThe influence of structurally related additives,namely N4-acetylsulfamerazine (NSMZ),sulfadiazine (SD)or sulfamethazine (SM),on the rate of the solvent-mediated polymorphic transformation (I -II)of sulfamerazine in acetonitrile (ACN)at 241C was studie d.Thetransformation rateis controlle d by thecrystallization rateof themore stable Polymorph II.All three impurities exhibit inhibitory effects on the crystallization of Polymorph II and hence stabilize the metastable Polymorph I in ACN suspension.The rank order of the inhibitory effect (NSMZ b SD>SM)is thesameas therank orde r of thebinding e ne rgy of theimpurity mole culeto thesurfaceof thehost crystal.The relationship between the concentration of the impurity and the inhibitory effect was fitted to various models and was found to be best described by a model based on the Langmuir adsorption isotherm.r 2002Published by Elsevier Science B.V.Keywords:Al.Adsorption;puter simulation;Al.Crystal structure;A1.Impurities;A1.Nucleation;A2.Growth from solutions1.IntroductionPolymorphs arecrystallinesolids with thesame chemical composition but with different arrange-ments and/or conformation of the molecules in a crystal lattice.The discovery and characterization of polymorphs areimportant in various fie lds,because different polymorphs exhibit significantlydifferent physicochemical properties.In the phar-maceutical field,for example,the sudden appear-anceof a morestablepolymorph,that was not discovered at the early stage of pharmaceutical development,can cause loss of time and resources [1].Solvent-mediated polymorphic transformation is an efficient method to prepare more stable polymorphs [2,3].Traceamounts of a structurally related impurity may exert significant effects on thekine tics of dissolution [4]and crystallization [5],leading to changes in the polymorphic transformation rate in solution.Such effects may delay the discovery of a more stable polymorph.*Corresponding author.Tel.:+1-612-624-3956;fax:+1-612-625-0609.E-mail address:grant001@ (D.J.W.Grant).0022-0248/02/$-see front matter r 2002Published by Elsevier Science B.V.PII:S 0022-0248(01)01784-5On the other hand,the presence of an impurity or additivemay assist thepre paration of theme ta-stablepolymorph,which may othe rwiserapidly transform to themorestablepolymorph [6].To exploit the superior properties of a metastable polymorph,additives may be used to stabilize kinetically the metastable polymorph by inhibiting the formation of more stable polymorphs.There-fore,it is important to understand the effects of impurities or additives on the polymorphic trans-formation ratein solution.Thetransformation from theme tastablePoly-morph I of sulfamerazine (SMZ)to the more stablePolymorph II at 241C (room temperature)was chosen as the model system,while N4-acetylsulfamerazine (NSMZ),sulfadiazine (SD),and sulfamethazine (SM)were each chosen in turn as theimpurity (Sche me1).2.Materials and methods 2.1.MaterialsSulfamerazine (SMZ,4-amino-N-[4-methyl-2-pyrimidinyl]benzenesulfonamide,Lot #47H0114,purity >99.9%),SD,and SM were purchased from Sigma Co.(St.Louis,MO).Polymorphs I and II of SMZ were prepared as described in a previous paper [3].HPLC grade acetonitrile (ACN)was purchased from Fischer Scientific (Pittsburgh,PA).Residual water in ACN wasminimized by adding molecular sieves and anhy-drous calcium sulfate (Drierite,Hammond,Xenia,OH).N4-acetylsulfamerazine (NSMZ,4-acetamido-N-[4-methyl-2-pyrimidinyl]benzene-sulfonamide)was synthesized as described by Roblin and Winneck [7].The starting materials,namely acetylsulfanilyl chloride and 2-amino-4-methyl-pyrimidine,were purchased from Aldrich Chemi-cal Co.(Milwaukee,WI).The final precipitated product was recrystallized twice from tetrahydro-furan.The water content of NSMZ,determined by Karl Fischer titrimetry,was 6.3%(w/w),which corresponds to the monohydrate [theoretically 5.6%(w/w)water].Dehydration was achieved by storing at zero humidity for 2weeks.The anhydrate form of NSMZ (water content o 0.5%,w/w)was used in the later experiments.2.2.Solvent-mediated polymorphic transformationThetransformation from theme tastablePoly-morph I to Polymorph II at 241C was studied in ACN [3].Polymorph I was suspended in its presaturated solution containing a known amount of an impurity at 241C.Thewe ight/volumeratio of suspended solid to solvent was 20mg/ml.The suspension was shaken by a wrist-action shaker (Model 75,Burrell,Pittsburgh,PA)at B 300strokes/min.A portion of the suspension was withdrawn and filtered at designated times and the polymorphic composition of thesolid phasewasS NHOONNC H3NH 2C H 3S N HOONN NH 2S NHOO N NC H 3C H 3C ONHsulfamerazine (SMZ)N4-acetylsulfamerazine (NSMZ)sulfamethazine (SM) sulfadiazine (SD)Scheme 1.Molecular structure of the host molecule,SMZ,and the impurity molecules,NSMZ,SD,SM.C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481472determined by powder X-ray diffractometry (PXRD,Siemens D5005,Germany),which was described in detail in the previous reports[3,8]. Meanwhile,the concentration of SMZ in the solution during thetransformation proce ss was determined at l¼307nm with a spectrophot-ometer(DU7400,Beckman,Irvine,CA)[9].The standard solution contained the same concentra-tion of theimpurity as thesolution in which SMZ was suspended.To determine the crystal growth rate of Form II, 270mg(90%)of Polymorph I and30mg(10%)of Polymorph II were geometrically mixed and were suspended in the solutions described above,to determine the polymorphic transformation rate. This high proportion of seeds(10%of II)obviated the primary nucleation step in the transformation. Thepolymorphic transformation rateso de te r-mined corresponded to the crystal growth rate of themorestablePolymorph II in solution[3].2.3.Scanning electron microscopy(SEM) Themorphology was analyze d by SEM(S-800, Hitachi,Tokyo,Japan)at an accelerating voltage of10kV.The samples were sputter-coated with platinum to a thickness of50(A.2.4.Calculation of the impurity–surface binding energyTheinte raction of theimpurity with a growing surfacemay becalculate d,assuming that the solvent has no effect on the available conforma-tions of the impurity molecule[10].Commercial software(Ce rius2t,Molecular Simulation Inc. San Diego,CA)was employed to calculate the binding energy of the impurity molecule to the crystal surface.The Dreiding2.21forcefield was used to minimize the structure and to calculate the energy.For purposes of comparison,the binding energy of one molecule of each impurity to afixed and defined crystal face was calculated according to the procedure described by Jang and Myerson [10].The binding energy was obtained by sub-tracting the energy of the impurity molecule in the corresponding conformation from the minimum total energy of the surface bound with a single impurity molecule.3.Results and discussion3.1.Inhibitory effect of impurities on the transformation of SMZ Polymorph I to Polymorph II in ACN suspensionSolvent-mediated transformation consists of three consecutive steps:dissolution of the less stablepolymorph;nucle ation of themorestable polymorph;and crystal growth of themorestable polymorph.Theimpurity may affe ct any or all of these three steps.It was found in a previous study that thetransformation ratein pureACN is controlled by the crystallization rate of SMZ Polymorph II[3].To determine the rate-limiting step in the presence of the impurity,the concen-tration of SMZ in thesolution was monitore d.The concentration vs.time profile(Fig.1)indicated that thetransformation ratein thepre se nceof impurity is still controlled by the crystallization rate of Polymorph II,because the concentration of SMZ was closeto thesolubility of theme tastable Polymorph I until all Polymorph I in thesuspe n-sion had transformed to Polymorph II.In the presence of impurity,both the nucleation rate and crystal growth rate(Table1)were reduced significantly.However,the effect of NSMZ is 01234560102030Time (h)Conc.ofSMZinsolution(mg/ml)Fig.1.SMZ concentration–time profile during polymorphic transformation(I-II)in ACN solution containing the impurity,NSMZ(E)or SM(’)or SD(m),at molefraction 1.71Â10À5.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481473much greater than that of SM and SD.The morphology of SMZ Polymorph II grown from solutions containing each of these impurities is shown in Fig.2.Themorphology of SMZ grown in the presence of SM or SD is similar to that grown in its absence.However,in the presence of NSMZ at a molefraction as low as3.43Â10À6, themorphology is change d to a plateshapewith dominant\001\faces.These results indicate that all three impurities inhibit the crystallization of SMZ Polymorph II and that therank orde r of the inhibitory effect is NSMZ b SD>SM.The rank order of the inhibitory effect of the impurity may be explained by examining the crystal structureof SMZ Polymorph II,which is shown in Fig.3[11].Theamino group on the phenyl ring serves as a hydrogen bond donor in thecrystal of Polymorph II.If a NSMZ mole cule substitutes for a SMZ molecule in the crystal lattice,the acetyl group of NSMZ,which has replaced a hydrogen atom in SMZ,will hence disrupt the hydrogen bond interaction with incoming SMZ molecules(Scheme1).Therefore, the rate of molecule incorporation,i.e.,the crystallization rate,will be reduced.In addition, at the nucleation stage,the incorporated impurity molecule may destabilize the molecular aggregates and facilitate the dissolution of the aggregate, resulting in a reduction of the nucleation rate.In this way,the nucleation and crystal growth process can be greatly disrupted by NSMZ.However,SM and SD differ from SMZ only in the methyl group on thepyrimidinering,which doe s not participate in the hydrogen bonding interaction.Therefore, SM and SD are less effective in inhibiting the crystallization process than is NSMZ.The inhibitory effect of the impurity does not follow therank orde r of themole cular sizeof the impurity.The molecular volumes and mole-cular surface areas of the impuritymolecules, Fig.2.Morphologies of the crystals of SMZ Polymorph II grown from ACN in the presence of impurities,NSMZ,SM,and SD.The molefraction of theimpurity in thesolution is1.71Â10À5.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481475respectively,are:NSMZ,244.6(A3,295.4(A 2;SM,225.1(A3,275.2(A 2;SD,196.3(A 3,233.4(A 2.3.2.Surface–impurity binding energyThe effects of impurities on crystallization kinetics are related to the strength of the inter-molecular interaction between the impurity and the terraces,steps,and kinks of the nuclei or crystals.Because crystal growth of SMZ in ACN follows theBCF me chanism,theimpurity inhibits crystal growth mainly by being adsorbed on to the steps and kinks.Chernov found that the decrease in step rate is proportional to the time when the kinks are free of impurities [12–14].If the lifetime of adsorbed molecules at kinks,steps,and terraces is shorter than the time required for the step to cover the interstep distance,impurities with great-er adsorption energy at kinks and steps are more likely to be adsorbed and thereby to inhibit the crystal growth.The adsorption energy at kinks and steps includes the adsorption energy on the terrace,which is proportional to the calculated solute–surface binding energy.The calculated solute and solvent binding energies (kcal/mol)to the crystal faces (001),(100),and (110),respec-tively,of SMZ Polymorph II are:NSMZ,À23.0,À20.4,À19.8;SM,À8.1,À14.5,À18.4;SD,À21.8,À17.6,À19.0;SMZ (host molecule),À19.5,À13.9,À12.2;ACN (solvent),À6.52,À6.13,À5.28.The greater the absolute value of the surface–impurity binding energy,the stronger the binding of impurity molecule to the surface,indicating higher probability of absorption on theste ps or kinks.The results show that all three impurities have greater binding energies to the individualcrystalFig.3.Crystal structure of SMZ Polymorph II [11].The dotted lines represent the hydrogen bonds.C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481476faces than does the host molecule,SMZ,and the solvent molecule,ACN,which supports the fact that all three impurities exert inhibitory effects. Among the three impurities,the binding energy of NSMZ is the greatest,followed by SD and then by SM,which is in agreement with the rank order of their inhibitory effects on both nucleation and crystal growth.Desolvation of both solute mole-cules and growth sites is an essential step in crystal growth.The difference in solvation energy be-tween the host molecule and the impurity mole-cule,compared to that at the growth sites,might also affect the binding preference of the solute molecules during crystal growth.This effect is neglected when the binding energy is compared.3.3.Relationship between the concentration of the impurity and the inhibitory effect on crystallization Several models have been developed to describe the dependence of the growth inhibitory effect of theimpurity on theconce ntration of theimpurity [15–19].The impurity molecules arefirst adsorbed onto the surface of a growing crystal,where they interfere with the further incorporation of SMZ molecules,causing the reduction in growth rate. Theamount of impurity adsorbe d onto thesurface may be described by the classical Langmuir adsorption isothermy¼kc1þkc;ð1Þwhere y is thefraction of thesurfacecove re d bythe impurity molecules,c is theconce ntration oftheimpurity in solution,and k is theratio of theadsorption rate coefficient to desorption ratecoefficient.If the adsorption of new molecules is subject toblocking by the adsorbed molecule or the surfacecontains unfillablevoids,themaximum proportionof the occupied area available for adsorption,y max;is less than unity(0o y max o1),corresponding to an empirical Langmuir equation[20].At equili-brium,the percentage of the surface coverage,y;may be expressed byy¼y max kc1þkc;ð2Þwhere y max is themaximum proportion of thesurfaceavailablefor adsorption,and theothe rparameters have the same meaning as definedpreviously.Because the classical Langmuir ad-sorption isotherm(Eq.(1))and the empiricalLangmuir adsorption isotherm(Eq.(2))have thesame form and therefore cannot be distinguishedwhe nfitting thedata,theclassical Langmuiradsorption isotherm is applied tofit the data inthe following models.The same value of thefittedparameters will be obtained when applying theempirical Langmuir adsorption isotherm tofit themodel,although thefitted parameters have differ-ent meanings.In order to model the inhibitory effect of theadsorbed impurity molecule on the crystal growth,the crystal growth mechanism needs to be deter-mined.The Jackson factor[5,21],a;may becalculated to estimate the growth mechanism bythefollowing e quation:a¼E sliceh k lE crystalD H sRT;ð3Þwhere E sliceh k lis the slice energy,E crystal is the energyof crystal formation,D H s is thehe at of solution,Ris thegas constant,and T is thete mpe rature[22].The a values are8.4for the(001)face,7.9for the(010)face,5.4for the(100)face,and6.5for theð1%11Þface[23].Be causethe a values are>5,crystal growth is likely to follow the BCFmechanism[5].Several established models fordescribing the dependence of the growth inhibitoryeffect on the impurity concentration[15–19]weretested byfitting to the experimental data[23].Boththe Cabrera–Vermileya model and the Kubota–Mullin model may describe the inhibitory effect ofimpurity on crystal growth following theBCFmechanism,but that proposed by Kubota andMullin[15]gave the bestfit to the experimentalresults.This equation for the latter model isf¼1Àe y;ð4Þwhere f is theratio of thecrystal growth ratein thepresence of impurity to that in its absence and e isthe inhibitory effectiveness factor of the impurity.The other symbols have the same meaning asdefined previously.In this model,the growth rateis assumed to be proportional to the step-C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481477advancement velocity.The impurities are adsorbed onto a linear array of active sites of steps to inhibit the step advancement.The inhibitory effect,e ;is determined by both the size of the impurity molecule and the strength of interaction between theimpurity and thecrystal surface .Be cause 0o y max p 1;when e >1and theconce ntration of impurity is high enough to make y ¼y max ;crystal growth may be blocked completely when the e y X 1:However,when e o 1;thecrystal growthrate will be reduced maximally to a value equal to (1Àe ),and the dependence of the inhibitory effect on the concentration of the impurity will level off at high concentrations of the impurity.Rearran-ging Eq.(4)with inserting Eq.(1)gives the following linear expression:1=ð1Àf Þ¼ð1=ek Þð1=x Þþð1=e Þ;ð5Þwhere x is themolefraction of theimpurity in the solution and theothe r symbols havethesame(a)(b)x (mole fraction)x (mole fraction)0.00000.00020.00040.00060.00080.00100.00120.00.20.40.60.80.00.20.40.60.8F r a c t i o n o f n u c l e a t i o n r a t e ( f )F r a c t i o n o f c r y s t a l g r o w t h r a t e ( f )Fig.4.Fitting of the experimental data to Eq.(4),which describes the model proposed by Kubota and Mullin [11].The lines are drawnbased on the parameters determined by Eq.(5),and the symbols represent the experimental results.(a)Fitting of the crystal growth data;and (b)fitting of the nucleation data.The impurities are NSMZ, ;SD,.;and SM,J .C.-H.Gu et al./Journal of Crystal Growth 235(2002)471–481478meaning as defined previously.The data in Table1 werefitted to Eq.(5)to determine the values of k and e(Table2).Thefit of thedata to Eq.(4)is shown in Fig.4a.The e valuefor NSMZ is slightly>1,which indicates that the crystal growth may cease completely when the concentration of NSMZ is high enough,at which point y is closeto unity.We found that,when the concentration of NSMZ reaches3.26Â10À4molefraction,thetransforma-tion virtually ceases.At this concentration,the model also predicts that the crystal growth rate will be equal to zero,which is in agreement with the experimental observations.In the presence of SM or SD,the e values are o1,which means that the maximum extent of reduction in the crystal growth rate by these two impurities is(1Àe).TheKubota–Mullin mode l predicts that the minimum crystal growth rate in the presence of SM or SD is27%or22%, respectively,of that in their absence.In Table1, the conversion time in the presence of SM reaches a plateau,2h,despite the increase of the SM concentration.This maximum time corresponds to theminimum growth ratein thepre se nceof SM, which is25%of thegrowth ratein its abse nce.In the presence of SD,the plateau value is2.25h, corresponding to22%of the growth rate in its absence.The predicted value agrees with the experimental value.In Table2,the rank orders of the values of k and e follow the rank order of the inhibitory effect and the rank order of the surface–impurity binding energy.The k value is directly related to the surface–impurity binding energy by the Arrhenius equation[24].The value of the effectiveness factor, e;is related to the strength of the interaction between the impurity molecule and the crystal surface,which may reflect the surface–impurity binding energy[25].Therefore,the calculated surface–impurity binding energy may serve to screen the inhibitory effect of the impurity. Unlike the mechanism for impurity effect on the crystal growth rate,the dissolved impurity may reduce the nucleation rate by occupying the active sites on prenuclear aggregates,thereby inhibiting their growth beyond the critical size of a stable nucleus,and/or by becoming incorporated into the prenuclear aggregates or nuclei,thereby disrupting them and facilitating their dissolution.If the impurity acts primarily by inhibiting thegrowth of prenuclei,the models for crystal growth may be applied to describe the relationship between the concentration of the impurity and the inhibitory effect on nucleation.However,if the impurity acts primarily by its incorporation,there lationship between the segregation coefficient and the con-centration of the impurity must be known to model the dependence of the inhibitory effect on theimpurity conce ntration.In this study,the relative nucleation rate is estimated by the reciprocal of the induction time (Table1).When the inhibitor prevents the molecular aggregates from growing into stable nuclei,the relationship between the concentration of theimpurity and there duction in nucle ationTable2Estimated parameters of the Kubota–Mullin model[15]for crystal growth inhibition based on Eq.(5)NSMZ SM SD Langmuir(Eq.(5))k 5.66Â105 4.55Â105 5.31Â105e 1.020.7280.781 Estimated minimum crystal growth rate a00.270.22 Minimum experimental crystal growth rate b00.250.22a Theminimum crystal growth rateis theminimum ratio of thecrystal growth ratein thepre se nceof an impurity to that in its absence.b The minimum experimental crystal growth rate is the ratio of the growth time in the absence of impurity to that with the highest concentration of impurity(Table1).C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481479ratemay bede scribe d by Eq.(4),in which f is the fraction of the nucleation rate in the presence of impurity to that in its absence.Fig.4b summarizes thefit to Eq.(4).Thefitting appears satisfactory,and the esti-mated minimum nucleation rates in the presence of various impurities agree with the experimental values.These results suggest that the impurity may retard the nucleation of Polymorph II by inhibit-ing the growth of the molecular aggregates. However,the experimental results do not exclude thepossibility that theimpurity may beincorpo-rated into the host lattice in the form of prenuclei and destabilizes them.With increasing concentra-tion of theimpurity in thesolution,theamount of incorporated impurity may reach a maximum, corresponding to the solid solubility limit of the impurity in thehost crystal[26].This maximum incorporation may also explain the constancy of the inhibitory effect at higher concentrations of SM and SD.The solid-state relationship between thehost crystal and theimpurity mole culewill be studied to examine the possibility of solid solution formation.4.Conclusions1.Structurally related additives significantly in-hibit thetransformation of Polymorph I of SMZ to Polymorph II in suspension in ACN, by inhibiting both thenucle ation and thecrystal growth of themorestablePolymorph II.2.The rank order of the inhibitory effect isN4-acetylsulfamerazine(NSMZ)b sulfadiazine (SD)>sulfamethazine(SM).This rank order agrees with the rank order of the binding energy of theimpurity to thecrystal surface.3.The relationship between the inhibitory effectand theconce ntration of theimpurity is be st described by a model proposed by Kubota and Mullin[15,16].When the concentration of NSMZ is sufficiently high(>6.86Â10À5mole fraction for nucleation or>3.26Â10À4mole fraction for crystal growth),both thenucle ation rateand thecrystal growth ratebe come negligible.However,in the presence of SD or SM,the nucleation rate is maximally reduced to13%or29%,respectively,with respect to that in theabse nceof theimpurity.Thecrystal growth rate is maximally reduced to25%by SM or22%by SD with respect to that in its absence.Theimpurity e ffe ct on thestabilization of a particular polymorph should be considered during polymorph screening.Because the impurity may delay the discovery of a polymorph,it is necessary to repeat the screen for polymorphs after the chemical purity of the material has been opti-mized.On the other hand,stabilization of a metastable polymorph with superior physicochem-ical properties may be achieved by adding an acceptable additive with a suitable binding energy. The kinetic models discussed in this paper may be used to estimate the concentration of the additive necessary to achieve stabilization of the metastable phase over the shelf life of a product. AcknowledgementsWethank Bristol–Mye rs Squibb for an unre st-ricted grant and also the Supercomputing Institute of the University of Minnesota forfinancially supporting our use of the Medicinal Chemistry/ Supercomputing Institute Visualization F Work-station Laboratory.References[1]S.R.Chemburkar,et al.,Org.Process Res.Dev.4(2000)413.[2]N.Rodriguez-Hornedo,D.Murphy,J.Pharm.Sci.88(1999)651.[3]C.H.Gu,V.Young Jr.,D.J.W.Grant,J.Pharm.Sci.90(2001)1878.[4]H.Bundgaard,J.Pharm.Pharmacol.26(1974)535.[5]J.W.Mullin,Crystallization,3rd Edition,Butterworth-Heinemann,London,UK,1993.[6]R.Vrcelj,H.Gallagher,J.Sherwood,J.Am.Chem.Soc.123(2001)2291.[7]R.O.Roblin Jr.,P.S.Winneck,J.Am.Chem.Soc.62(1940)2002.[8]G.Zhang,Influence of solvents on properties,structures,and crystallization of pharmaceutical solids,Ph.D.Thesis, Department of Pharmaceutics,University of Minnesota, Minneapolis,MN1998,pp.70–122.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481 480[9]R.D.G.Woolfender,in:K.Florey(Ed.),AnalyticalProfiles of Drug Substances,Academic Press,New York, NY,1977,pp.515–517.[10]A.S.Myerson,S.M.Jang,J.Crystal Growth156(1995)459.[11]K.R.Acharya,K.N.Kuchela,J.Crystallogr.Spec.Res.12(1982)369.[12]A.A.Chernov,in: A.V.Shubnikov(Ed.),Growth ofCrystals,3rd Edition,Consultant Bureau,NY,1962,p.31.[13]A.A.Chernov,p.4(1961)116.[14]A.A.Chernov,Modern Crystallography III CrystalGrowth,Springer,Berlin,1984,p.162.[15]N.Kubota,J.W.Mullin,J.Crystal Growth152(1995)203.[16]N.Kubota,M.Yokota,J.W.Mullin,J.Crystal Growth182(1997)86.[17]M.C.van der Leeden,D.Kashchiev,G.M.van Rosmalen,J.Crystal Growth130(1993)221.[18]R.J.Davey,J.Crystal Growth34(1976)109.[19]N.Cabrera,D.Vermilyea,in:B.Doremus,B.W.Roberts,D.Turnbull(Eds.),Growth and Perfection of Crystals,Wiley,New York,NY,1958,p.393.[20]Z.Adamczyk,B.Siwek,M.Zembala,P.Belouschek,Adv.Colloid Interface Sci.48(1994)151.[21]K.A.Jackson,Liquid Metals and Solidification,AmericanSociety of Metals,Cleveland,OH,1958.[22]P.Bennema,J.Phys.D26(1993)B1.[23]C.H.Gu,Influence of solvent and impurity on thecrystallization process and properties of crystallized product.Ph.D.Thesis,Department of Pharmaceutics, University of Minnesota,Minneapolis,MN,2001.[24]M.Rauls,K.Bartosch,M.Kind,S.Kuck,cmann,A.Mersmann,J.Crystal Growth213(2000)116.[25]N.Kubota,M.Yokota,J.W.Mullin,J.Crystal Growth212(2000)480.[26]Z.J.Li,D.J.W.Grant,Int.J.Pharm.137(1996)21.C.-H.Gu et al./Journal of Crystal Growth235(2002)471–481481。
不同国家乳木果油品质研究作者：李一峰陈志韶戴伟杰阚启鑫王耀华曹庸来源：《食品安全导刊》2024年第05期摘要：本文以乳木果油为原料，旨在全面研究加纳、乌干达和布基纳法索乳木果油的油脂品质。
通过理化性质对比、气相色谱-质谱联用法分析脂肪酸组成、高效液相色谱仪分析甘油三酯组成，考察3个国家乳木果油的成分和品质。
结果表明，乌干达油脂得率最高，为51.82%；加纳乳木果油具有更低的酸价、水分、过氧化值和不溶性杂质，同时有更高的不皂化物含量；气相色谱-质谱联用法共检测出12种脂肪酸，油酸、硬脂酸、亚油酸和棕榈酸为3种乳木果油主要脂肪酸，这4种脂肪酸总含量均超过95%，而乌干达乳木果油具有更高的不饱和脂肪酸含量；高效液相色谱仪检测出SOS和SOO为3种乳木果油的主要甘油三酯，乌干达乳木果油含有更多OOO甘油三酯，含量为其他两个国家的6倍以上。
综上所述，加纳乳木果油具有更好的油脂品质，而乌干达乳木果油的高不饱和脂肪酸和高OOO含量也为乳木果油的使用拓宽了应用范围。
关键词：乳木果油；理化指标；脂肪酸；甘油三酯Shea Butter Quality Study in Three African CountriesLI Yifeng1， CHEN Zhishao1， DAI Weijie1， KAN Qixin2， WANG Yaohua3， CAO Yong2*（1.Guangdong Huiertai Biotechnology Co.， Ltd.， Guangzhou 510700， China;2.School of Food Science， South China Agricultural University， Guangdong Key Laboratory of Functional Food Actives， Guangdong Engineering Technology Research Center for Natural Actives， Guangzhou 510642， China;3.Yunnan Hill Biotechnology Co.， Ltd.， Kunming 650214， China）Abstract： The purpose of the experiment was to comprehensively investigate the oil quality of shea butter in Ghana， Uganda and Burkina Faso. The composition and quality of shea butter in the three countries were investigated by physicochemical property comparison， gas chromatography-mass spectrometry analysis， and high performance liquid chromatography analysis of triglyceride composition. The results showed that the yield of oil in Uganda was the highest （51.82%）， and the content of Ghanaian shea butter was lower in acid value， moisture， peroxide value， insoluble impurities， and higher in unsaponifiable substances， and 12 fatty acids were detected by gas chromatography-mass spectrometry， among which oleic acid， stearic acid， linoleic acid andpalmitic acid were the three main fatty acids of shea butter， and the total content of these four fatty acids exceeded 95% high performance liquid chromatography showed that SOS and SOO were the main triglycerides of the three shea butters， and Uganda shea butter had more OOO triglycerides，which were more than 6 times higher than those in the other two countries. In summary， Ghanaian shea butter has better oil quality， while the high unsaturated fatty acid and high OOO content of Uganda shea butter also broadens the application range of shea butter.Keywords： shea butter; physicochemical indexes; fatty acids; triglycerides乳木果油的提取源自“乳油木”，“乳油木”所結果实的果肉常用于食用，而果核中的油脂就是乳木果油，大约占果实质量的一半。
ORIGINAL PAPERComparison of physicochemical properties of chitins isolated from an insect (Melolontha melolontha )and a crustacean species (Oniscus asellus )Murat Kaya •Vykintas Baublys •Esra Can•Ingrida Sˇatkauskien _e •Betu ¨l Bitim •Vaida Tubelyt _e•Talat Baran Received:6February 2014/Revised:25February 2014/Accepted:27February 2014/Published online:16March 2014ÓSpringer-Verlag Berlin Heidelberg 2014Abstract The chitin structures of two common European species belonging to Insecta (Melolontha melolontha )and Crustacea (Oniscus asellus )were isolated.The same pro-cedure is followed for chitin isolations for both the species.First,HCl was used for removing of minerals in the organisms,and then,the protein structure was removed by using NaOH.Chitins obtained from these two species were characterized physicochemically.Physicochemical prop-erties of chitins isolated from the insect and the crustacean were compared to each other.The chitin content for dry weights of M.melolontha and O.asellus were recorded as 13–14and 6–7%,respectively.The results of Fourier transform infrared spectroscopy,thermogravimetric ana-lysis and X-ray diffraction analysis were found to be more or less similar.The surface morphologies of chitins wereexamined via environmental scanning electron microscopy and nanofibers,and pore structures were observed.While the chitin nanofibers of O.asellus were adherent to each other,nanofibers of M.melolontha were non-adherent.On the other hand,the number of pores was much higher in the chitin from M.melolontha than in the chitin from O.asellus .Looking at the elemental analysis results,the M.melolontha chitin was found to be more pure than the O.asellus chitin.For this reason,M.melolontha has been considered more attractive source for chitin than O.asellus .Keywords Chitin ÁNanofiber ÁPorous ÁInsecta ÁCrustacea ÁExtraction ÁThermal propertiesIntroductionInsecta is a class with more than one million species,but only a few of them have been investigated for their chitin structures (Zhang et al.2000;Nemtsev et al.2004;Paulino et al.2006;Majtan et al.2007;Sajomsang and Gonil 2010;Gonil and Sajomsang 2012;Liu et al.2012).Insects are found all over the world.When environmental conditions are appropriate,insects reproduce very quickly and there may be an excessive increase in population (Zhang et al.2000).Insects can be used for chitin production,when there is an over-abundant increase in the population for any insect.Studies on chitin isolation and characterization focus often on big-sized organisms (crab,prawn,crayfish)belonging to Crustacea (Zhao et al.2010).Generally these organisms live in aquatic ecosystems.A small-sized crus-tacean living in aquatic ecosystems,Gammarus argaeus ,searched for chitin isolation and physicochemical charac-terization (Kaya et al.2013).In the present study,for theCommunicated by A.Schmidt-Rhaesa.M.Kaya ÁE.Can ÁB.BitimDepartment of Biotechnology and Molecular Biology,Faculty of Science and Letters,Aksaray University,68100Aksaray,Turkey M.Kaya ÁE.Can ÁB.Bitim ÁT.BaranScience and Technology Application and Research Center,Aksaray University,68100Aksaray,TurkeyM.Kaya (&)Department of Biotechnology and Molecular Biology,Science and Arts Faculty,Aksaray University,Aksaray,Turkey e-mail:muratkaya3806@V.Baublys ÁI.Sˇatkauskien _e ÁV.Tubelyt _e Department of Biology,Vytautas Magnus University,44404Kaunas,LithuaniaT.BaranDepartment of Chemistry,Faculty of Science and Letters,Aksaray University,Aksaray,TurkeyZoomorphology (2014)133:285–293DOI 10.1007/s00435-014-0227-6first time,a small-sized terrestrial crustacean species, Oniscus asellus,was examined for chitin isolation and characterization.The same method was used for chitin extraction from an insect and a crustacean species to see changes of physicochemical properties in chitin structures.Chitin is a biopolymer naturally found in the exoskeleton of some organism groups such as Trilobitomorpha,Chelic-erata,Crustacea,Myriapoda and Hexapoda.However,chitin is found in the cell wall of fungi and yeast(Rinaudo2006), and body structure of Anthozoa(Bo et al.2012;Jua´rez-de La Rosa et al.2012)and diatoms(Durkin et al.2009).Chitin and chitosan are produced for commercial purposes and having wide range of applications due to their antimicrobial and antioxidant effects,nontoxic feature,biodegradability and biocompatibility.Because of these advantages,chitin and chitosanfind applications in the textile industry,as a food preservative,in controlled drug release,wound healing,gene delivery and tissue engineering(Synowiecki and Al-Khateeb 2003;Rinaudo2006;Muzzarelli et al.2007;Aranaz et al. 2009;Park and Kim2010;Muzzarelli2011).M.melolontha(common cockchafer)is an insect belonging to the family Scarabaeidae.It is much abundant insect species in Europe,and also,it is known as a major pest in the cyclical years of‘‘massflight’’(Fraval1998).Adult individuals feed on bush and leaves of trees,and they are rarely a problem of any significant harm.But the larvae of this species can be urgent pests in nurseries,gardens and pastures because they eat roots of plants in the soil(Fraval1998).The woodlouse O.asellus is very common terrestrial isopod species in Europe.This crustacean lives beneath rocks,leaves and logs in meadows,forests and gardens (McKenzie1997).O.asellus plays an important role in the ecosystem by degrading organic compounds and returning nutrients to the soil.This species is saprophagous, coprophagous,mycophagous and detritivorous(Zimmer 2002).As a chitin source,this species offers the advantages of being easily captured and cared for in captivity.Thus, the woodlouse may prove to be a good source of chitin for industrial use in biotechnology,medicine and other industries that use chitin or chitosan as a raw material.The purpose of this study was to extract and characterize the chitin from one insect and one crustacean species comparatively.Moreover,the feasibility of using these species as a chitin source was evaluated during the over-growth and harmful situations.Materials and methodsSamples collectionAdult individuals of M.melolontha were captured from Puvociai in the Varena region of Lithuania in June2013.O.asellus samples were collected from Karmelava in the Kaunas region of Lithuania in November2013.Insects were killed using ether as a killing agent.Isopods were killed by freezing and allowing them to thaw at room temperature.DemineralizationIn the laboratory,samples of M.melolontha and O.asellus were washed several times with distilled water.The sam-ples were then dried in an oven at60°C for24h.The dried samples were crushed mechanically in a mortar.Two grams of powder samples for each species were refluxed in 50ml of4M HCl solution at75°C,by heating the mag-netic stirrer for2h.The samples were washed with dis-tilled water to form a neutral pH.At this point,the demineralization process was complete.DeproteinizationThe acid-treated samples were refluxed with4M NaOH to remove proteins,at150°C for18h,using a heater magnetic stirrer system.After this procedure,the samples were washed with distilled water again,to make a neutral pH,using pore-sizedfilter paper of1l m in diameter.DecolorizationAfter deproteinization,the samples were stirred in a mixture of water,alcohol and chloroform(4:2:1rate, respectively)at room temperature for20min.Once again,the samples were washed with distilled water using1-l mfilter paper;following this,the samples were put in an oven to dry at60°C for24h.The chitin contents of the species were calculated using the dry weight of the obtained material.It is noted that the same procedure was used for the chitin extraction from the two species.Kaya et al.(2013)and Kaya et al.(2014)were followed for chitin extraction process.Fourier transform infrared spectroscopy(FTIR)Isolated chitins from M.melolontha and O.asellus were analyzed at4,000–625cm-1using Perkin–Elmer FTIR spectrometer.Environmental scanning electron microscopy(ESEM)Sputter Coater(Cressingto Auto108)brand equipment was used for gold cover of the chitins,andfigures were taken by using QUANTA-FEG250ESEM.Thermogravimetric analysis (TGA)Chitins isolated from M.melolontha and O.asellus were analyzed using EXSTAR S117300with a temperature rate change of 10°C per min from 25to 650°C.X-ray diffraction (XRD)X-ray diffraction peaks of chitins isolated from M.melolontha and O.asellus were taken at 40kV,30mA and 2h using a Rigaku D max 2000system (with a scan angle from 5°to 45°).Crystalline index (CrI)values of chitins were calculated using the formula below (Al Sagheer et al.2009):CrI 110¼I 110ÀI am ðÞ=I 110½ Â100ð1ÞI 110is the maximum intensity at 2h %19°.I am is the intensity of amorphous diffraction at 2h %13°.Elemental analysisElemental analyzer Flash 2000mark elemental analyzer was used to determine the %C,N and H contents of thechitins.Degree of acetylation of chitins extracted from M.melolontha and O.asellus were calculated using the for-mula (Xu et al.1996):DA ¼½ðC =N À5:14Þ=1:72 Â100ð2ÞResultsChitin content of Melolontha melolontha and Oniscus asellusChitin contents are varied between 13–14and 6–7%for the dry weight of M.melolontha and O.asellus ,respectively.FTIRThe FTIR bands were observed for M.melontha :3,441,3,263,3,103,2,926,2,870,1,656,1,621,1,552,1,424,1,376,1,308,1,155,1,112,1,069,1,010,952,895cm -1;and for O.asellus :3,434,3,262,3,100,2,930,2,873,1,654,1,620,1,553,1,424,1,376,1,308,1,154,1,113,1,068,1,008,952,897cm -1(Fig.1).Fig.1FTIR bands of chitins isolated from a Melolontha melolontha and b O.asellusFE-SEMSurface morphologies of chitins that had been isolated from an insect species(M.melolontha)and a crustacean species(O.asellus)were examined using FE-SEM.Pores and nanofibers were observed on the surface of both forms of chitins(Figs.2,3).The chitin of M.melolontha was found to be much more porous than that of O.asellus. Nanofibers are non-adherent on the surface of the chitin isolated from M.melolontha(Fig.2),but the nanofibers on chitin surface of O.asellus were adherent(Fig.3).The diameters of pores were185–400and100–250nm for the chitin of M.melolontha and O.asellus,respectively;and the widths of nanofibers were25–45and10–25nm for M. melolontha and O.asellus,respectively.TGAThe TGA analysis results for both chitins were recorded similarly,and mass losses were observed in two steps.In thefirst step,4and5%mass losses were observed between0and150°C for M.melolontha and O.asellus, respectively,as a result of water evaporating from the structure.In the second step,mass losses were evidenced between150and600°C at78%for M.melolontha and 77%for O.asellus(Fig.4).This second mass loss was attributable to the deterioration of chitin molecules.The temperature at which maximum degradation occurs (DTGmax)was found to be380°C for M.melolontha and 387°C for O.asellus(Fig.4).XRDIn total,six peaks were observed in the examination of chitins from M.melolontha and O.asellus by XRD (Fig.5).CrI values were calculated at75.2%for M. melolontha chitin and75.3%for O.asellus chitin.Elemental analysisIn the present study,the N contents of chitins from two species were measured: 6.72%for M.melolonthaand Fig.2ESEMfigures of chitin extracted from Melolontha melolontha(Magnifications:a98,000,b916,000,c930,000and d940,000)4.7%for O.asellus.The DA values of the chitins were calculated according to the formula given in the materials and methods section.The DA values of the chitins were calculated as91.27and168.71%for M.melolontha and O. asellus,respectively.The chitin extracted from O.asellus has a low N content and a high DA value,indicating the presence of some inorganic materials in the chitin structure.DiscussionHolotrichia parallela,belonging to the same subfamily (Melolonthinae)as M.melolontha,comprises of15% chitin in dry weight(Liu et al.2012).Chitin contents of some insects have been studied,and the amount varies from20%for silkworm chrysalides(Paulino et al.2006), 15–20%for Bombyx mori(Zhang et al.2000)to36%for cicada sloughs(only outer covering)(Sajomsang and Gonil 2010).Chitin content offive different species living in aquatic ecosystems is in the range of10–20%(Kaya et al.2014).Overall,depending on the species,the chitin content of insects has been found to be varied between10and 36%.Asellus aquaticus,belonging to the same subphylum Crustacea as O.asellus,possesses similar morphology with regard to body shape and size as O.asellus,although the habitat is different;while A.aquaticus lives in aquatic environments,O.asellus lives in terrestrial ecosystems. However,the chitin content of two species has been found to be in the similar range with A.aquaticus having5–6% chitin content(Kaya et al.2014).Crab and shrimp shells are composed of about20%chitin(Al Sagheer et al. 2009).G.argaeus lives in the aquatic environment and has quite small body size compared to crab and shrimp.Chitin content in G.argaeus is11–12%of its dry weight(Kaya et al.2013).FTIR spectroscopy is one of the most widely used techniques,in which the crystalline form of the chitin to determine.After the examination of FTIR spectrums,the observed bands1,660cm-1[(–C=O)and amide II of (–NH)groups of the hydrogen bonds absorption]and Fig.3ESEMfigures of chitin extracted from O.asellus(Magnifications:a910,000,b920,000,c930,000and d940,000)1,620cm -1[(–CH2ÁOH)groups and carbonyl groups of the hydrogen bonds absorption]indicate that the chitin is in a -form (Focher et al.1992a ,b ).It is reported that FTIR spectrum of b -chitin shows only a single band near 1,620cm -1(intramolecular hydrogen bands)(Gardner and Blackwell 1975).In the present study,we observed the bands for chitins at 1,656–1,620cm -1for M.melolontha and at 1,654–1,620cm -1for O.asellus .These bands around 1,650and 1,620indicate the chitins in the a -form.Also,these bands are evidence of a -chitin (Acosta et al.1993).Ifuku et al.(2009)reported that widths of chitin nanofibers isolated from crab shells vary in width between 10and 100nm.On the other hand,nanofiber widths on chitin isolated from crab and prawn shells have been observed as uniform,lying between 10and 20nm (Ifuku et al.2010,2011a ).Widths of fungal chitin nanofibers were found to be between 20and 28nm,depending on the fungi species (Ifuku et al.2011b ).In the present study,widths of O.asellus chitin nanofibers were found to be very similarto those of other crustacean chitin nanofibers,but the widths of chitin nanofibers extracted from M.melolontha were observed to be much higher than those of nanofibers isolated from crab,prawn and fungi species.In previous studies on insect chitin surface,SEM figures were taken,but widths of nanofibers could not be calcu-lated due to insufficient magnifying capacity (Sajomsang and Gonil 2010;Liu et al.2012).Chitin surface morphol-ogies of five different insect species were examined,and it was observed that all the chitins consisted only of nanofi-bers without pores (Kaya et al.2014).On the other hand,chitin from silkworm chrysalides was found to be highly porous.In the present study,we observed both pores and nanofibers on the chitin surfaces obtained from M.melo-lontha and O.asellus .Porous and nanofiber chitin struc-tures,similar to those found in our study,were seen in chitins from crabs and prawns (Yen et al.2009;Ifuku et al.2010,2011a ).The mass losses were observed in two steps which examined the TGA analysis results of chitinsextractedFig.4TGA Thermograms and DTG curves of chitins from a Mel-olontha melolontha and b O.asellus Fig.5XRD peaks of chitins isolated from a Melolontha melolontha and b O.asellusfrom crabs,shrimp,insects and anthozoans similar to our results(Jang et al.2004;Sajomsang and Gonil2010;Ju-a´rez-de La Rosa et al.2012).DTGmax values observed between350and380°C in other studies resembled our values(380–387°C)(Kittur et al.2002;Paulino et al. 2006;Sajomsang and Gonil2010;Wang et al.2013).Normally,two sharp(around9°and19°)and four weak peaks(about13°,21°,23°and26°)have been found when examining chitin isolated from various organisms such as insects,crabs,shrimp,fungi and anthozoans(Jang et al. 2004;Sajomsang and Gonil2010;Jua´rez-de La Rosa et al. 2012;Liu et al.2012).We observed two sharp(9.44°and 19.48°)and four weak peaks(12.7°,20.82°,23.4°and 26.62°)in the chitin from M.melolontha,but three sharp (9.2°,19.26°and26.62°)and three weak peaks(13.02°, 20.64°and23.76°)were seen in the chitin from O.asellus (Fig.5).Here,an extra sharp peak at26.62°was observed in the chitin from O.asellus.This sharp peak at26.62°possibly shows the remains of inorganic materials still present in the structure.The CrI values of chitin and chitosan are of great importance in determining their effective application areas (Aranaz et al.2009).The CrI value was found to be 89.05%for the chitin of H.parallela,which is within the same subfamily as M.melolontha(Liu et al.2012).On the other hand,the CrI values of chitins isolated from larva cuticles and silkworm pupa exuviae were found to be54 and58%,respectively(Zhang et al.2000).Isolated chitins from one crustacean andfive insect species were evaluated for their CrI values,and the values for each species were between76.4and90.6%(Kaya et al.2014).The CrI values of chitins extracted from cicada slough,rice-field crab shell and shrimp were recorded at around90%(Sa-jomsang and Gonil2010;Liu et al.2012).Chitins fromfive fungi species were searched for their CrI values,and the results ranged from47.6to80%(Ifuku et al.2011b).In this instance,it can be seen that the CrI value of chitins changes considerably depending on the species,and maybe the isolation procedures.Thermal properties of chitins such as mass losses and DTGmax values were found very similar.And also,CrI values of the chitins were observed very close.These similarities of thermal properties and CrI values are prob-ably for using the same isolation methods.The nitrogen(N)percentage of chitin is an extremely important indicator of its purity.The nitrogen content of completely acetylated(pure)chitin is known to be6.89% (Majtan et al.2007;Sajomsang and Gonil2010;Liu et al. 2012).Nitrogen levels higher than6.89%indicate that protein residues may be present in the chitin sample,while nitrogen levels lower than6.89%suggest that inorganic materials may not have been fully removed(Sajomsang and Gonil2010).Additionally,a DA value higher than 100%suggests that some inorganic materials remain in the chitin(Sajomsang and Gonil2010).The DA values of chitins previously isolated from various other organisms were observed to be higher than 100%,and the N contents of these species were all lower than 6.89%(Table1).These results indicate that the chitins isolated in other studies contained inorganic materials,similar to the chitin extracted from O.asellus in the present study.During fungal chitin extraction,it is impossible to remove glucan from the chitin structure using chemical methods(Ifuku et al.2011b).Therefore, the reported DA values of fungal chitins are generally higher than100%.The high DA values shown in Table1 represent fungal chitins isolated from Hypsizygus mar-moreus,Grifola frondosa and Lentinula edodes.The results of other elemental analyses and the DA values of chitins obtained from different organisms are given in Table1.FTIR and TGA analysis results were found to be very similar for both chitins isolated from M.melolontha and Table1Elemental analysis results and DA values of chitins isolated from various organismsSamples C(%)N(%)H(%)DA(%)ReferencesMelolonthamelolonthachitin45.09 6.72 6.2991.27Present studyOniscus aselluschitin38.44 4.78 5.15168.71Holotrichiaparallela chitin44.36 6.45 5.92101.02Liu et al.(2012) Shrimp chitin43.75 6.24 6.40108.79Cicada sloughschitin40.85 5.92 6.12102.3Sajomsang andGonil(2010) Rice-field crabshells chitin42.64 6.15 6.45104.2Crude crab chitin41.1 5.37.1151.7Yen et al.(2009) Purified chitin44.4 6.27.5117.5Bumblebee chitin43.92 5.92 6.43132.5Majtan et al.(2007) Shrimp chitin44.72 4.85 6.47237.2Chitin powderfrom crab shells47.29 6.89100.2Ifuku et al.(2011a,b) Pleurotus eryngiichitin45.43 6.37115.8Agaricus bisporuschitin43.69 6.19111.5Lentinula edodeschitin45.3 4.89239.76Grifola frondosachitin42.72 3.67377.9Hypsizygusmarmoreuschitin43.77 2.96560.9O.asellus.A sharp peak was observed at26.62°;low N% content and high DA values of chitin isolated from O. asellus suggest remnant inorganic materials in the chitin structure.For these reasons,chitin from M.melolontha is a much more attractive source than chitin from O.asellus. 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