Octenylsuccinate Derivatives of Carboxymethyl Starch – Synthesis and Properties

Carboxymethyl starch (CMS, DS_CM 0.1) was modified with octenylsuccinic anhydride in various solvent systems. Using the dimethyl sulphoxide (DMSO)/p‐toluenesulphonic acid (p‐Ts‐OH) system, carboxymethyl starch octenylsuccinates (OS‐CMS) were obtained with degrees of substitution (DS) ranging from 0.03 to 0.53 at high reaction efficiency, and characterized with regard to their molecular structure, their rheological and surface active properties. The water‐soluble OS‐CMS derivatives showed a pseudoplastic behavior dependent on both the DS and polymer concentration (c_p). The thickening power displayed a maximum at DS 0.14 at higher c_p (2.5 and 5.0%). In spite of the only moderate surface‐tension decreasing effect of the OS‐CMS derivatives, most of them exhibited excellent emulsifying, foaming and antiredeposition effects. They represent novel polysaccharide‐based biosurfactants with a broad application potential.     

Low power microwave‐assisted enzymatic esterification of starch

A series of starch esters was obtained using microwave‐assisted enzymatic transformation of starch. For the reaction hog pancreas lipase was used as a biocatalyst as well as followed acyl donors: acetic, lauric, and stearic acid. DMF and DMSO were applied as a reaction media. Experiments focused on low level microwave irradiation were compared with conventional heating of the reaction mixture. The structure of obtained starch esters was investigated by means of FTIR, analysis of substitution degree, changes in molecular parameters (M_Ws and M_Ws distributions), and microscopic studies (SEM). The spectroscopic analysis confirmed the ester bond formation. The microwave‐assisted reaction in DMF and lauric acid as an acyl donor, gave the highest degree of substitution (0.513) what followed the lowest polysaccharide degradation and maintaining the granular structure of starch. According to all the results the significant shortening in the reaction time (about 2.5 times) for microwave‐assisted reactions were observed. The influence of microwaves on esterification of starch was discussed focusing on reaction media and acyl donor type. The investigated reaction systems were demonstrated as new protocols for obtaining starch ester with higher efficiency in comparison to those known as conventional. Replacement of sophisticated derivatives including vinyl esters or acyl chlorides by simple acyl donors were shown as an additional benefit of proposed starch esterification method.     

Microwave‐assisted Synthesis of Starch Maleate by Dry Method

Starch maleate was prepared by microwave‐assisted reactions. Microwave‐assisted esterification in a dry medium for 5 min gives a reaction efficiency of 98%. Influences of reaction time, reagent molar ratio and water content of starch on the degree of substitution (DS) of the product and reaction efficiency were investigated. The structure of starch maleate was characterized by FTIR and NMR spectroscopy. Changes in the starch granules before and after modification were studied by scanning electron microscopy (SEM). Compared with the conventional heating synthesis method, microwave‐assisted synthesis in a dry medium is rapid and energy saving with high reaction efficiency.     

Effect of low‐energy X‐ray irradiation on physical,chemical, textural and sensory properties of Dates

The effect of X‐ray irradiation as postharvest treatment on physical, chemical, textural and sensory attributes of Khalas dates (Phoenix dactylifera L.) was investigated. The surface of dates was subjected to low‐energy X‐ray irradiation at 3, 5 and 7 KGy. While some physical and chemical properties of dates were significantly different between treatments (fruit hardness, crude protein, total fat, tannins, total fibre and insoluble fibre), there was no detrimental effect on the quality (crude fibre, soluble dietary fibre, sucrose, glucose, fructose, moisture, total soluble solids, pH, water activity, colour and sensory evaluation). The sensory acceptability of X‐ray irradiated dates was significantly lower at 5 and 7 KGy than for untreated control. Irradiation at 3 KGy did not contribute to significant changes in physical, chemical or textural properties of dates. Adaptation to low‐energy X‐ray irradiation can be used as a potential commercial treatment for retaining the quality and ensuring the safety of dates.     

Microwave‐accelerated Synthesis and Characterization of Potato Starch‐g‐poly(acrylamide)

Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O₂ removal from the reaction vessel was not required. Under optimal conditions, grafting and efficiency observed were 160% and 89%, respectively. Grafted starch was characterized by using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). It was observed that the microwave irradiation could significantly accelerate the synthesis of starch‐graft‐poly(acrylamide), because under identical conditions no grafting was observed in a conventional procedure. Viscosity, shear stability and water/saline solution retention of the microwave‐synthesized grafted starch were studied and compared with that of the parent starch.     

Preparation of water‐soluble starch oligomers from variable starch species in 1‐allyl‐3‐methylimidazolium chloride

Native wheat, barley, rice, maize, wx maize, and potato starch species were modified by depolymerization in 1‐allyl‐3‐methylimidazolium chloride ([AMIM]Cl) ionic liquid (IL) using oil bath or microwave heating. Reactions were catalyzed with p‐toluenesulfonic acid (p‐TsOH). Reaction times varied depending on the starch species and its concentration, the heating method, and volume of the reaction mixture. Depolymerization products were analyzed with HPLC‐ELSD. All starch species mostly degraded into water‐soluble 1500–2000 Da‐sized starch oligomers. Glucose and other short‐chained sugars did not precipitate along with starch oligomers due to their high solubility in IL. This property was utilized in the purification of commercial maltodextrins. Produced water‐soluble, low MW starch oligomers might be used, e.g., in bacterial cultivations as a glucose source.     

糠酸正丁酯的超声辅助PMo12/SnO2催化合成及其动力学研究

采用简单浸渍法制备了Sn O2负载的磷钼杂多酸(PMo12/Sn O2),并采用X-射线衍射和扫描电镜对其进行了表征。以PMo12/Sn O2为催化剂,利用超声作用,快速合成了糠酸正丁酯并研究了其反应动力学。通过单因素实验法研究了各因素对糠酸正丁酯产率的影响,得出了最佳反应条件:醇酸物质的量比为3:1,催化剂0.50 g,带水剂5 m L,超声作用时间15 min,超声波功率200 W。在此条件下糠酸正丁酯的产率达到97.5%。与文献报道的其他方法相比,超声辅助PMo12/Sn O2催化合成糠酸正丁酯具有需时少、产率高、能耗低等特点。测定了343 K、353 K和363 K时催化反应的动力学参数,结果表明糠酸正丁酯的超声辅助PMo12/Sn O2催化合成反应符合二级动力学方程,其反应表观活化能为27.85 k J/mol。与单纯超声酯化法、PMo12/Sn O2催化酯化法、直接水浴加热酯化法相比,由于超声处理与PMo12/Sn O2催化之间可能存在某种协同作用,超声辅助PMo12/Sn O2催化合成法显著降低了酯化反应的表观活化能,促进了反应的快速进行,提高了糠酸正丁酯的产率。     

Evaluation Antibacterial Activity of Quaternary‐Based Chitin/Chitosan Derivatives In Vitro

Abstract: Total of 3 water‐soluble quaternary‐based chitin/chitosan derivatives, which have an identical molecular weight and anion, were synthesized and characterized. Their antibacterial activities against Salmonella cholerae‐suis and Bacillus subtilis were evaluated in vitro. The polysaccharides exhibited the antibacterial efficiency. Their minimum inhibitory concentration (MIC) values vary from 0.02 to 20.48 mg/mL, and their minimum bactericidal concentration (MBC) values vary from 0.08 to 40.96 mg/mL against S. cholerae‐suis and B. subtilis, respectively. Futhermore, the extent of Bacillus subtilis cells damage was examined via transmission electron microscopy (TEM) to show how N,N,N‐trimethylchitosan (TMC) gradually destroyed and killed B. subtilis cells when they were treated with TMC. One of those quaternary polymers, O‐([2‐hydroxy‐3‐trimethylammonium])propyl chitin (OHT‐chitin), which can be directly and easily synthesized from chitin in bulk quantities, also was demonstrated its antibacterial activity. These water soluble quaternary‐based chitin/chitosan derivatives that have antibacterial effect should be potentially used as antimicrobial agents in many fields. Practical Application: The main practical application behind the investigation and evaluation antibacterial activity of 3 water‐soluble quaternary‐based chitin/chitosan derivatives could be potentially used as antimicrobial agents in many fields. These polysaccharides represent a renewable source of natural biodegradable polymers and meet with the emergence of more and more food safe problems.     

Improved Extraction and Quality Characterization of Water‐Soluble Polysaccharide from Gamma‐Irradiated Lentinus edodes

Gamma irradiation was applied to the improved extraction of water‐soluble polysaccharides (WSPs) from dried Lentinus edodes. Irradiation provided a dose‐dependent increase in extraction yield (0 kGy, 2.01%; 7.5 kGy, 4.03%; 15 kGy, 7.17%) and purity (0 kGy, 78.8%; 7.5 kGy, 83.1%; 15 kGy, 85.6%) of the WSPs from hot‐water extraction. The effect of irradiation was evident in the degraded microstructures and reduced molecular weights of the WSPs. However, nuclear magnetic resonance, Fourier‐transform infrared, and X‐ray diffraction spectroscopic analyses provided comparable structures of WSPs from nonirradiated and irradiated samples. UV–visible spectra showed a dose‐dependent decline in intensity, but an improvement in thermal properties of the WSPs from the irradiated mushroom samples was observed.     

Study on microwave‐accelerated casein protein grafted with glucose and β‐cyclodextrin to improve the gel properties

The effect of glycosylation treatment coupled with microwave heating (MH) on gel properties and structure change of casein were investigated. Conjugation was confirmed by electrophoresis. Protein disulphide bonds were broken by microwave irradiation to create an increase first and a decrease later in free sulfhydryl contents with time, thereby inducing subunit disaggregation. Also, the exposure of hydrophobic core residues was increased in MH‐treated casein, which brings about protein disaggregation and unfolding. It showed that graft reactions by MH had much faster than those by water bath heating (WH). The content of disulphide bonds is 7.2% and 6.0% in the casein–glucose and casein–β‐cyclodextrin, respectively, treated by MH which was reduced significantly than that of treated by WH. Moreover, MH can increase the hardness of the gel. Consequently, MH could improve the efficiency of the reaction and gel properties.     

Physicochemical and antioxidant properties of non‐refined sugarcane alternatives to white sugar

Antioxidant properties of commercial sugarcane‐derived products were analysed to study their suitability for being used as functional ingredients. Cane honey, several jaggeries and several brown sugars were selected from the market and analysed in terms of physicochemical characteristics and antioxidant properties, and compared with white refined sugar (twelve products in total). Moisture, water activity, total soluble solids, pH, colour and sugar profile are reported. As for antioxidant properties, total phenols and flavonoid content, as well as antiradical ability (DPPH˙ and the TEAC‐ABTS methods), are given. All sugarcane products contained phenols and flavonoids and exhibited in vitro antioxidant activity, determined by degree of refining. Among the alternatives analysed, jaggeries and cane honey showed the best antioxidant properties. Thermal treatment did not significantly affect the antioxidant capacity of sugarcane products, especially jaggeries. As sugar‐rich products are widely consumed worldwide, the use of non‐refined sugarcane derivatives in food formulation is encouraged.     

机械活化协同微波法制备高取代度柠檬酸酯淀粉

在微波辐射条件下,以不同机械活化时间的木薯淀粉为原料,柠檬酸为酯化剂,氢氧化钠为催化剂制备柠檬酸酯淀粉。以取代度和反应效率为指标,分别探讨机械活化时间、微波功率、微波辐射时间、淀粉含水量、柠檬酸用量及氢氧化钠用量对木薯淀粉柠檬酸酯化反应的影响,并对影响因素进行了正交优化。结果表明,木薯淀粉经机械活化后,对微波功率、微波辐射时间、酯化剂用量、催化剂用量、淀粉含水量的依赖性明显降低,取代度和反应效率均为原木薯淀粉的2倍多。通过正交试验确定了制备柠檬酸酯淀粉的最佳工艺条件:微波功率800 W、微波辐射5.0 min、淀粉含水量35%、柠檬酸质量分数50%、氢氧化钠质量分数6%,所得产品的取代度为0.399 8,反应效率为88.84%。并采用红外光谱和X-射线衍射对木薯淀粉、活化淀粉及高取代度柠檬酸酯淀粉进行了表征。     

Optimisation of the microwave‐assisted extraction process for six phenolic compounds in Agaricus blazei murrill

An efficient microwave‐assisted extraction (MAE) technique was employed in the extraction of phenolic compounds from Agaricus blazei murrill, and phenolic compounds were quantified by High‐performance liquid chromatography (HPLC). The MAE procedure was optimised, validated and compared with other conventional extraction techniques. MAE gave the best result because of the highest extraction efficiency within the shortest extraction time. The optimal conditions of MAE were 60% ethanol, ratio of solid/liquid 1:30, temperature 110 °C, irradiation power 500 W and three extraction cycles, each 5 min. This is the first report on combining MAE with HPLC for the extraction and quantification of phenolic compounds in A. blazei murrill. The developed MAE method provided a good alternative for the extraction of phenolic compounds in A. blazei murrill as well as other materials.     

Extraction of pure lycopene from industrial tomato by‐products in water using a new high‐pressure process

BACKGROUND: Lycopene, a precursor of β‐carotene with a well‐known antioxidant activity, contained in many natural products such as tomato (Lycopersicon esculentum Mill.), watermelon, red pepper and papaya, is usually recovered from natural vegetal sources using organic solvents and a purification step. In this paper an innovative process for the extraction of pure lycopene from tomato waste in water that uses the Naviglio^® extractor and water as extracting phase is presented. RESULTS: Lycopene was obtained in the all‐trans form at a very high grade of purity, not less than 98% (w/w), with an average recovery of 14% (w/w). The availability of high‐purity trans‐lycopene allowed measurement of the molar absorption coefficient. An alternative procedure for high‐performance liquid chromatographic analysis using a phenyl‐hexyl silicone phase as inverse phase and a linear gradient in water and acetonitrile is also described. CONCLUSIONS: The use of water as extracting phase considerably reduces the cost of the entire process when compared with the commonly used solvent‐based procedure or with the newer supercritical extraction process of lycopene from tomato waste. Lycopene, not soluble in water, was recovered in a quasi‐crystalline solid form and purified by solid‐phase extraction using a small amount of organic solvent. Copyright © 2008 Society of Chemical Industry This article was published online on September 15, 2008. Errors in Figures 2 ‐ 4 were subsequently identified. The publishers wish to apologise for these errors. This notice is included in the online and print versions to indicate that both have been corrected [September 19, 2008]     

Chemical Acylation of Water‐Soluble Antioxidant of Bamboo Leaves (AOB‐w) and Functional Evaluation of Oil‐Soluble AOB (cAOB‐o)

Antioxidant of bamboo leaves (AOB) is a novel natural food antioxidant approved in China since 2004. Natural phenolics contained in the current AOB are usually polyhydroxy derivatives exhibiting hydrophilic character, which has been marked as water‐soluble AOB (AOB‐w). In order to broaden the application fields, oil‐soluble AOB (cAOB‐o) was obtained by chemical acylation of AOB‐w with different chain‐length fatty acids varying from C8 to C18. Results indicated that the yield and solubility of cAOB‐o in 1‐octanol solvent depended on the carbon chain length of acyl donor, and cAOB‐o derived from C12 fatty acid exhibited the more powerful antioxidant activity evaluated by β‐carotene/linoleic acid bleaching assay. Total phenolic content decreased by Folin–Ciocalteu assay. Fourier transform infrared spectra showed the increase of a carbonyl (C = O) peak at 1701 cm^?1 and a decrease in the intensity of the absorption at 3400 cm^?1 (O‐H stretching) in cAOB‐o. Acylation was inferred to mainly occur on the hydroxyl groups of flavones C‐glycosides according to the change of high‐performance liquid chromatography spectra and the contents of total flavonoids and phenolic acids. cAOB‐o with the addition of 0.02% significantly increased oxidative stability of palm oil 1.59 times, lard 3.74 times, and fried potato chips 2.08 times, which was better than the effect of oil‐soluble tea polyphenol (P < 0.01). Moreover, cAOB‐o was identified to be actually nontoxicity by an acute oral toxicity test. All the above results indicated that cAOB‐o could be used as a novel and effective oil‐soluble antioxidant in the food industry.     

Impact of cell wall‐degrading enzymes on water‐holding capacity and solubility of dietary fibre in rye and wheat bran

BACKGROUND: Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water‐holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well‐defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. RESULTS: The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. CONCLUSION: None of the enzymes increased the water‐holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased. © 2012 Society of Chemical Industry     

Influence of Various Cooking Methods on the Concentrations of Volatile N‐Nitrosamines and Biogenic Amines in Dry‐Cured Sausages

Abstract: N‐nitrosamines, biogenic amines, and residual nitrites are harmful substances and are often present in cured meats. The effects of different cooking methods (boiling, pan‐frying, deep‐frying, and microwave) were investigated on their contents in dry‐cured sausage. The various N‐nitrosamines were isolated by a steam distillation method and analyzed by gas chromatography mass spectrometry (GC‐MS). The biogenic amines were determined after extraction with perchloric acid as dansyl derivatives by high‐performance liquid chromatography (HPLC) method. The results showed that initial dry‐cured raw sausage contained 5.31 μg/kg of total N‐nitrosamines. Cooking by deep‐frying or pan‐frying resulted in products having the highest (P < 0.05) contents, compared with boiling or microwave treatments, which were not different from the raw. Although frying increased the content of N‐nitrosodimethylamine (NDMA), N‐nitrosodiethylamine (NDEA), and N‐nitrosopyrrolidine (NPYR), it decreased the contents of histamine and cadaverine. Boiling and microwave treatments decreased the total biogenic amines significantly (P < 0.05). Residual nitrite was significantly reduced by cooking treatments. The results suggest that boiling and microwave treatments were more suitable methods for cured meat. Practical Application: N‐nitrosamines and biogenic amines are considered potentially harmful substances to humans and often present in dry‐cured sausage. Different cooking methods may effect the content of these harmful substances. However, little information exists on the different cooking methods on dry‐cured meats.     

A comparative study on viscosity behavior of water‐soluble chemically modified guar gum derivatives with different functional lateral groups

A comparative study was carried out on the viscosity behavior of three new water‐soluble chemically modified guar gum derivatives with different functional lateral groups, including O‐carboxymethyl‐O‐hydroxypropyl guar gum (CMHPG), with anionic character, O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar gum (HTPG), with cationic character, and O‐carboxymethyl‐O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar (CMHTPG), with amphoteric character. It was found that the shear rate, concentration, temperature, added salt and surfactant affected the viscosity properties of these new guar gum derivatives in aqueous solutions. Regardless of the functional lateral groups, all sample solutions behaved as non‐Newtonian shear‐thinning fluids, and their viscosity increased with the increase in their concentration but decreased with the increase in temperature. Aqueous CMHTPG solution had the strongest shear‐thinning property, and aqueous CMHPG solution investigated had the greatest viscous flow activation energy. In contrast to cationic HTPG or anionic CMHPG, amphoteric CMHTPG had an enhanced viscosity property in aqueous salt solutions, exhibiting an unusual anti‐polyelectrolyte viscosity behavior. The addition of sodium dodecylsulfate was found to result in a decrease in the viscosity of aqueous HTPG solution and an increase in the viscosity of aqueous CMHPG solution or CMHTPG solution. Copyright © 2005 Society of Chemical Industry     

Starch Derivatives of High Degree of Functionalization. 7. Preparation of Cationic 2‐Hydroxypropyltrimethylammonium Chloride Starches

Water‐soluble starch derivatives containing quarternary ammonium groups of high degree of substitution are prepared by reacting starch with 2,3‐epoxypropyltrimethylammonium chloride in different reaction media. The reaction was carried out in aqueous sodium hydroxide under dissolution of the product, in dimethyl sulfoxide homogeneously, and completely heterogeneously in ethanol/water. The DS values of up to 1.1 in an one‐step synthesis of the samples can be controlled by adjusting the molar ratio of cationization agent to anhydroglucose unit and are only slightly dependent on the amylose content of the starting starch material. A two‐step reaction yields products of a DS of up to 1.5. The structure of the cationic starch derivatives was confirmed by means of elemental analysis, FTIR‐ and NMR spectroscopy as well as GC‐MS.