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In paper conservation practice, adhesives are used for several purposes, such as mending tears and gaps, or paper consolidation. The criteria to choose one or another adhesive should be based on the knowledge of the properties and stability of those adhesives. However, the several different adhesives available on the market still lack enough information to help the process of a rational decision-making. In the present work, five adhesives currently used in the paper conservation field (starch paste, unsupported ArchibondTM, carboxymethylcellulose, hydroxypropylcellulose and methylcellulose) were analyzed for their chemical stability and fungal bioreceptivity (the ability of a material to be colonized by fungi). Bioreceptivity of products used in conservation and restoration is a still poorly explored subject, despite its great relevance for the preservation of objects. The chemical and physical properties of the adhesives, before and after moist heat artificial ageing, were analyzed by thermogravimetry, capillary viscometry, measurement of water absorption capacity, colourimetry, and pH measurement. Fungal bioreceptivity of the adhesives was tested on two different substrates (paper and glass) against three fungal species: Aspergillus niger, Aureobasidium pullulans and Penicillium pinophilum. Along 56 days of incubation, the colonization area on the adhesives was measured through digital photo analysis. Starch paste was the most bioreceptive adhesive, but on other hand was also the most stable adhesive to artificial ageing, regarding colour alteration, degree of polymerization and pH. Carboxymethylcellulose and ArchibondTM showed chemical deterioration with ageing. Nevertheless, these two adhesives presented only scarce bioreceptivity to the tested fungi. Methylcellulose and hydroxypropylcellulose showed the best relationship between higher chemical stability with artificial ageing and lower fungal bioreceptivity.

Single use food packaging made from expanded polystyrene (EPS) is generally discarded after use and, since it is a difficult material to recycle, generates a large amount of waste. The EPS can be replaced by thermoplastic starch (TPS) foams, which are made from renewable sources and are biodegradable. However, TPS foams are hydrophilic and absorb large amounts of water, which makes it difficult to use. An alternative to this problem is to chemically modify the starch to make it more hydrophobic. Two modifications for potato starch were evaluated: acetylation and esterification with maleic anhydride. Foams with 6.67%, 13.34%, 20% and 26.67% (modified starch weight/ total starch paste mass) of modified starch were prepared. While TPS foams without modified starch absorbed 75 g water /100 g solids, foams with 13% acetylated starch and 20% esterified starch presented lower absorption results (42 g and 45 g water/100 g solids, respectively), which represents an improvement in water resistance.

When a starch paste stretches and breaks during dropping under gravity, the length of fully stretched paste drop is considered as an important flowing characteristic of starch. The length of paste drop (LPD) often determines eating quality of the starch-containing foods. The relationship between pasting parameters measured using a rapid visco-analyzer and LPD of various starches from different botanical sources was investigated at different starch concentrations (50, 70 & 90 g/kg). Starch content in the paste mainly affected the single pasting parameters (p

We present a methodology to predict the storage modulus ( G ’ ) of starch paste due to granule swelling, given the physical properties of the starch granule and temperature history. This was tested on experimental measurements of granule size distribution and G ’ for 8% w/w suspensions of waxy maize, normal maize, waxy rice, normal rice, and cross linked normal maize – all heated to different temperatures (65–90 °C) with holding times between 2 and 60 min. Experimental data of storage modulus G ′ vs volume fraction φ fall onto a master curve when G ′ is normalized by a multiple of γ / R ‾ , where γ is the granule-solvent interfacial energy, and R ‾ is the average granule size. We show that one can combine this master curve with starch swelling theories to forecast the time-dependent rheology of starches. This work also demonstrates that granule-solvent interfacial energy is a key physical parameter in controlling starch rheology.

In this study, we aimed to examine the effects of different low concentrations of alcohol solution (5%–20%) on the gelatinization and pasting properties of pea starch. A rapid visco analyzer revealed that when the starch concentration was fixed, the viscosity of the starch paste decreased with increasing alcohol concentration. In addition, the texture analyzer results showed that compared to the hydrogel formed in water, the hardness of the gel formed by 15% starch in 10% alcohol increased approximately 2-fold (1696.4 g versus 928.1 g). Furthermore, the rheological results showed that the tan δ value of the gel formed under this condition was second only to that of 20% starch in water, which indicated the gel had a strong network structure. X-ray diffraction analysis showed an increased relative crystallinity of 15% starch gels formed in 10% alcohol (13.2%) compared to the hydrogel formed in water (12.2%). Our study will expand the knowledge of the gelatinization properties of starch in low concentrations of alcohol.

Materials used in this research were residual oat flour and starch isolated from it, and wheat flour and starch were used as reference. Pasting temperature of the starch present in flour or isolated starch increased with increasing syrup concentration, depending on material and syrup concentration. The maximum values of oat flour and starch paste viscosity were achieved at 30–40% syrup concentration, and at 50% for wheat pastes. Oat flour and starch pastes were pseudoplastic shear thinning fluids. In presence of syrup they revealed lesser deviation from Newtonian properties. Mechanical spectrum analysis of oat flour and starch pastes revealed stronger elastic than viscous properties. The hardness of flour gels prepared in syrup was higher than aqueous ones, and was increasing with increasing syrup concentration. It was stable during 7 days of storage. Adhesiveness of oat flour gels with syrup were lower than aqueous ones, reverse situation was observed for wheat flour gels. During storage, oat gels showed an increase of adhesiveness, in contrast to wheat gels, that were characterized by only initial increase of adhesiveness.

Improving the stickiness of non-glutinous rice is an important strategy in scaling out the applications of rice foods, e.g. Sushi, Zongzi etc. In this study, the effect of HPH treatments on the transparency and molecular structure of starch and the stickiness of cooked non-glutinous rice were investigated by cooking rice with high-pressure homogenization (HPH) thinned starch paste. HPH treatments significantly increased the light transmittance of starch paste from 7.6% to 81.3% (p

This study aimed at exploring the effects of exogenous seed crystals on the starch recrystallization. A-type and B-type seed crystals from rice starch were added to rice starch paste during cooling to analyze the changes in retrogradation process. DSC results indicated that B-type seed improved the uniformity of crystal size and the degree of crystal perfection; it also affected the nucleation mode of retrograded starches at 4 °C, while A-type seed did not affect these properties. The XRD showed that the unit cell was compact, and the crystal grain became larger upon the introduction of B-type seed, while A-type seemed to loosen the cell. The SAXS reflected that B-type seed increased the thickness of the imperfect lamellar structure formed during recrystallization, while A-type seed decreased it. These findings might be due to the molecular segment arrangement on the nuclei growth surface affecting the arrangement of starch molecular segments approaching the nuclei.

The novel hyperbranched poly(trimellitic glyceride) (PTG) starch plasticizer synthesized in our previous study was neutralized with different alkaline metal hydroxides. Mixed with starch, the effects of different alkaline metal cations, M+, on gelatinization of starch suspensions and thermal behaviors of the films were analyzed using RVA and DMA, respectively. The structures of the starch suspensions, films and freeze-dried samples (S/PTG-M) were investigated using DSC, XRD and FTIR spectroscopy, respectively. M+ increased the gelatinization temperature of starch suspensions in the order of S/PTG-Li > S/PTG-Na > S/PTG-K. The formation of a complex between M+ and starch in the films observed using FTIR spectroscopy improved the stability of the starch paste and gel, and increased the gel temperature of starch dispersions. The corresponding starch gel was relatively thermostable, but not shear-resistant. PTG decreased the Tg of starch films with different paired M+. PTG-Li and PTG-K, but not PTG-Na, strengthened the mechanical properties of starch films.

The aim of the present study was to determine the viscoelastic properties of the model mixtures of selected pasted polysaccharides. The initial materials used were water pastes of waxy corn and normal corn starch, mixed with guar gum. The rheological tests were performed in a time domain. The theoretical analysis covered the adaptation of some achievements of the phenomenological theory of viscoelasticity, which were applied during the interpretation of the results obtained for the aforementioned mixtures of biopolymers. The emphasis was placed on the description of the retardation behaviours with the aim to develop a continuous rheological Burger model.

The α-amylase enzyme has been reported during the last decade to be used for removal of the excess starch adhesive paste, which is usually used to fix textiles on paper, textiles, wood panels, or other rigid support materials. The final aim of this work was the application of α-amylase in order to remove the old starch from historical textiles in an attempt to conserve them under mild conditions. An extensive study was undertaken using various types of textiles in order to identify the optimum condition for the use of the enzyme, in relation to time, concentration, temperature and pH, before any other attempt. The first step was to simulate the textile ageing. The fabrics were coated with starch paste adhesive, and then a process of artificial thermal ageing was made on samples for different periods of time. After that the enzyme was applied to the samples, at different concentrations and at different intervals. This study also presents interesting results concerning the effect of the enzymatic treatment on the mechanical and optical parameters of linen, silk and cotton, dyed with madder or turmeric dye mordanted with CuSO4 or ferric citrate. Finally, the removal of enzymatic residues from textiles after the treatment has been studied. The application section has been fulfilled by using the whole process in a piece of a historical carpet from fabric adhered with starch. This piece of carpet is in the museum of the Faculty of Applied Arts, Helwan University in Egypt.

A modified equation of state was developed for shear-thickening systems. The model was applied for describing the rheological properties of various starch pastes for describing the rheological properties of various starch pastes and pastes with hydrocolloids addition. The parameters of the model were estimated using the Tikhonov regularisation method. In order to compare the results, some other models were also fitted to the experimental data.

This study was designed to investigate the effect of a thermostable α-glucanotransferase (TSαGT) originated from Thermus scotoductus on the rheological properties, molecular weight distribution, thermo-reversibility, and freeze-thaw stability of rice starch paste. Rice starch paste samples (5%) were incubated at 70 °C with TSαGT and a commercial α-amylase, respectively, until reduction of moduli leveled off. The TSαGT-modified rice starch paste showed a yield stress. After the enzymatic treatment, both enzyme-treated pastes showed considerably low moduli with higher G ″ than G ′, indicating a significant liquefaction. However, when stored at 4 °C, both moduli of a TSαGT-treated sample dramatically increased with significantly higher G ′ than G ″, confirming that a solid gel structure formed. This transition was found to be reversible, when temperature fluctuated between 70 and 4 °C. The control starch gel did not show thermo-reversibility, and α-amylase-treated starch paste was incapable of forming a solid gel. The size distribution of the starch polymers, as measured by MALLS, revealed that average M w reduced to about 5×10 5 after the TSαGT treatment, which was a significant decrease, but possibly high enough to form a solid gel matrix at low temperatures. The TsαGT-treated gel demonstrated highly improved freeze-thaw stability.

Swelling and pasting properties of 15 starches from different plant origins were studied to elucidate their relationship with structural features using simple and multiple regression analyses. Avoidance of additional effects of starch minor components showed that swelling power and pasting parameters were associated with the ratio of the relative molar distribution of amylopectin branch-chains with a degree of polymerization (DP) of 6–12 to that of chains with DP 6–24 (amylopectin unit-chain (APC) ratio). Swelling power of starch granules increased with APC ratio. Multiple regression analysis revealed that the peak viscosity (PkV) of starch paste increased with low APC ratio, low amylose content (AC) and large average granule size (AGS). At a high starch concentration, pasting temperature (PT) was reduced by a high APC ratio and large AGS. Peak time (PkT) decreased with increasing APC ratio and AC. Percentage of breakdown viscosity (BD%) and setback viscosity (SB) were primarily affected by APC ratio. At a low concentration, AC and AGS had more profound effects on BD%. SB was also reduced by higher AC. Models of pasting profile, which is influenced by individual factors, were also proposed.

The study was carried out in order to determine and establish the functional characters of starch extracted from yam bean (Pachyrhizus erosus (L) Urban) compared with cassava starch. Yam bean is a tropical tuber legume easily grown and holds a great potential as a new source of starch. Yam bean starch shows functional properties which are peculiar to those of most starch root crops. Gelatinization temperature (53-63 degrees C) and the pasting temperature (64.5 degrees C) are less than those of cereal starch, however, the swelling power is high (54.4 g gel/g dried starch). Yam bean starch paste presents a high viscosity profile, high retrogradation tendency and low stability on cooking. The functional properties of yam bean starch, similar to those of cassava starch, allows yam bean to be used as a potential new source of starch.

Ten rice starches with a fairly narrow range of amylose content, but wide variation in RVA pasting curves, were selected to study a possible relationship between amylopectin fine structure and RVA paste viscosity parameters. Amylopectin fine structure was found to significantly correlate with paste breakdown. Proportion of long chains of amylopectin (FrI) was negatively correlated (r=0·84, p

A method of producing alumina fibres has been developed. The process used a water-based alumina and rice starch paste. An initial feed-rod was made from a central cylindrical rod of alumina paste surrounded by a square shaped section of starch paste. This feed rod was subsequently extruded so that it is reduced in size by a determined ratio. The extrudate was cut into short lengths and re-assembled to the exact dimensions of the initial feed rod so that it contained many smaller alumina rods. This latter specimen was re-extruded and the steps repeated as many times as required to obtain a large amount of small diameter fibres. By selecting the die diameter and the number of extrusions the diameter of the fibres was easily controlled. Since all the fibres were in one easily handleable bunch, the bottleneck associated with sintering could be avoided. Hence an economic method of fibre production can be envisaged.

Modern conservation ethics require that any repair carried out to a work of art should be removable at a later date without damage to the object. This paper discusses some of the traditional adhesives used by conservators of works of art on paper, highlights some of the probleme caused by the use of pressuresensitive tapes, Cow Gum® and hot-melt adhesives, and outlines some of the novel techniques which have been devised using modern synthetic products ucts vided of the use of this method on a homopolymer and the surface treatment of polypropylene

Different types of Crosslinked waxy-corn starches and pregelatinized-crosslinked waxy-corn starches were evaluated for potential use as a binding agent in a conventional wet granulation process. Lactose granules were prepared by granulation in a planetary mixer using starch as a binding agent in either the dry or paste form. The granules, prepared with dry starch or starch paste, showed no difference in size distribution and average size of granules. The pregelatinized starch used in the paste form gave coarser granules with a greater average size in comparison to other starch modifications. In general, the friability of granules prepared by using dry starch is higher than that when using starch paste. Nevertheless, starches that were only pregelatinized or pregelatinized and crosslinked yielded granules having a similar friability by using either a dry starch or starch paste. The lactose granules prepared by using a paste of pregelatinized-crosslinked starch provided more friable granules with greater friability as compared to only pregelatinized starch paste. No difference in friability was observed between granules prepared with different types of pregelatinized-crosslinked (phosphate and adipate) starches. There was no difference in moisture content between all granules prepared in this study. The pregelatinized starch and pregelatinized-crosslinked starches showed potential use as a binding agent in the conventional wet granulation process. The starches that were Crosslinked only showed no advantage in binding properties over native corn starch or waxy-corn starch.

In cooking, the functional properties of food hydrocolloids are a valuable means of evaluating the quality of the cooked food and detecting the changes caused in the food properties during the cooking process. The fundamental properties and structure of the hydrocolloid sols and gels are reflected, both directly and indirectly, in the cooking properties. This study focuses mainly on the roles played by various hydrocolloids in cooking. Furthermore, the cooking properties of starch are examined in detail as an example. The subjects of (i) the thermal insulating property of starch paste; (ii) transitions in the properties during the gelation process; and (iii) transitions in the properties of blancmange caused by cooking, etc. are reviewed through rheological experiments and sensory evaluations.

Raw Chinese noodles were made from a number of experimentally-milled flours. The principal factors governing the eating quality of the noodles when boiled were protein content, dough strength and starch paste viscosity. In each case there was an optimum range outside which quality declined. Noodle brightness was related inversely to protein content and to flour colour grade.

The design and construction of a laboratory size dryer and other accessories suitable for investigating the drying rate kinetics of granules under controlled external conditions are described. Granulations of lactose and sulfathiazole, representing water‐soluble and insoluble materials, were prepared using various commonly used binders, and their drying rates were determined. The binders and diluents affected the drying rate curves for these granulations both qualitatively and quantitatively. Granules made with starch paste and gelatin solution required maximum time and energy for drying and those made with simple syrup USP required the least among the binders studied. Generally, three linear slopes were observed when the drying rate was plotted against the moisture remaining, indicating that granulation drying may be considered as occurring through three distinct phases.

This paper is concerned with a discussion of a method of manufacture for tablet granulations in which active ingredients comprise a major portion of the tablet. The method involves the use of standard coating pans in which granulations are formed by spraying with starch paste or other commonly used granulating solutions and subsequent drying in the pan.

The rate of crop emptying was studied in normal and operated females of Leucophaea maderae . Regardless of the amount of rat food consumed during one feeding period, 50 to 60 per cent of it was emptied from the crop within 24 hr. The rate of crop emptying is thus determined by the initial amount of food taken in and remains constant for 2 days at which time no food remains in the crop. The rate of food release from the crop is considerably higher after a feeding on starch paste than after a meal on solid rat food pellets. Thus consistency of food (solid or soft) is an additional factor which determines the rate of crop emptying. The opening of the proventricular valve appears to be controlled by either the ingluvial or the proventricular ganglion, but superimposed on these may be a certain amount of control by the frontal ganglion. Removal of the brain, corpora cardiaca, or corpora allata singly or all together do not influence the rate of crop emptying. The hypothesis is advanced that the degree of stretch of the crop by the food and consistency of the food is recorded by the stomatogastric nervous system which in turn then controls crop emptying.

1. 1. Measurement of the flow properties of starch pastes with the precision and accuracy required for industrial purposes is feasible. The methods described utilize the Corn Industries viscometer and a modified Stormer viscometer. The former provides a continuous record of the change in flow properties during pasting at a controlled cooking temperature; the latter supplements the data obtained during pasting with a rate of shear-shearing stress curve from which the apparent viscosity, expressed in poises, can be computed at any given rate of shear. 2. 2. Rheological data on a variety of commercial starches were obtained. The effect of rate of shear, concentration of the starch, and other factors are discussed. In all cases a curve typical of pseudoplastic flow was obtained. 3. 3. Continuous decrease in apparent viscosity occurs during the pasting process with the greatest change in the first hour; for many starches a fairly level viscosity is obtained after one hour cooking at 90–92°C. Vigorous agitation, in contrast to that obtained with low-speed sweep agitators, produces a more rapid decrease in viscosity, but differences in agitation apparently do not alter the nature of the pasting process. 4. 4. The effect of rate of shear on the computed values for apparent viscosity is great. Satisfactory measurements can be made only when the rate of shear is constant or when the magnitude can be determined and specified. The measuring methods described are reproducible and characterize the starches with respect both to rate of pasting and the flow properties of a given paste at different rates of shear. Industrial measurements can be made more precise by these means, and discrepancies in standardization and grading can be largely eliminated.

Experimental granulations were produced using aqueous and alcoholic solutions of polymeric celluloses, vinyls, acrylamides, pyrrolidones, oxazolidinones, and ethylene oxide condensation products. Products were compared to control formulations granulated with starch paste. Dextroamphetamine sulfate was employed in a preliminary dialysis and dissolution study in the presence of the polymers shown to be of value. The experimental products exhibited gloss equal or superior to coated tablets in many instances, and no drug binding or inhibition of release occurred. The polymer-bound granulations displayed excellent flow properties, were easily compressed into tablets of various degrees of hardness, were generally more resistant to friabilation than the control; some of the polymers produced tablets which had equal or superior disintegration times compared to the control.