Investigation on Changes in Physical and Technological Properties of Water Soluble Sizing Agents During the Ultrafiltration Process. Part I: Ultrafiltration of Hydroxy Propyl Starch

The effect of ultrafiltration (UF) operation on the stability of a sizing agent based on starch has been studied. Hydroxypropyl starch (HPS) has been used as a water soluble modified starch. The investigation was carried out in two categories:

• a) effect of UF time (the concentration of the solution was kept constant by recirculating the permeate), and
• b) raising the concentration by discharging the permeate.

The changes in the HPS solution properties were assessed by investigating the rheological properties (apparent viscosity as a function of filtration time, temperature and activation energy of flow) and molecular properties (Infra-Red spectroscopy (IR), number of average molecular weight (Mn) and molecular weight distribution). The investigation was carried out on HPS solutions before, after and during the ultra-filtration process. The results indicated that some degradation takes place during UF process.     

Properties of Starch Films and their Improvement

The tensile strengths and elongations of starch films prepared from various unmodified and modified starches were measured. These properties were improved by addition of urea and polyvinyl alcohol to the starch paste. The results obtained were as follows.

• 1 The heating temperature greatly affected the tensile strength and elongation of various unmodified starches. Potato starch gave the best film.
• 2 Introduction of hydroxyethyl groups into corn starch had unexpectedly little affect on the properties of the films.
• 3 A combination of hydroxyethylation and acid-modification slightly improved the properties of the films.
• 4 No film could be obtained after combinations of hydroxyethylation and hypochlorite-oxidation, pyrodextrinization or α-amylase-dextrinization. However, addition of urea to these modified starches resulted in good films.
• 5 On addition of urea the elongation of starch films increased and the pastes adhered uniformly to water repellent surfaces.
• 6 A film with the best properties was prepared from a mixture of 67% acid-modified hydroxyethyl starch, 13% urea and 20% polyvinyl alcohol.

     

Optimized Water Routing in Corn Wet Milling

Presently two methods are practiced to route the process water in a corn wet milling system. Each method will be discussed how it accomplishes the removal of soluble solids from the final-starch product. Subsequently, a modified method of water routing will be presented. It is an improved counter washing system and offers higher soluble removal efficiencies. The three different means of water routing will be compared quantitatively, and it will be shown that the modified water routing offers the following benefits:

• 1 Reduced Fresh Water Requirement
• 2 Reduced Fuel Requirement
• 3 Easier Process Control
• 4 Improved Gluten Yield

     

Zur Frage der Verwendung von Natriumdisulfit statt schwefliger Säure bei der Maisstärkeproduktion

Sodium disulphite (Na₂S₂O₅) has a less active effect on the extraction of corn colloids. The crude protein content of the colloids amounts to a total of 35%. On the Question of Using Sodium Disulphite instead of Sulphurous Acid in Corn Starch Production.

• 1 Comparative examinations have been carried out on the composition of extracts, which had been abtained by steeping of corn in sulphurous acid, sodium disulphite solution and water, respectively.
• 2 It was found that the presence of chemical reagents in the solution used for the steeping of corn, increases the diffusion of extractive substances (especially of the high-molecular ones) from the corn kernel into the steeping water. The most active reagent in this action is sulphurous acid because of its reducing properties and its faculty of increasing the permeability of the cell walls.
• 1 A certain difference in the effect of sulphurous acid and sodium disulphite solution on the colloidal matter of the corn kernel has been found. The highest total amount of colloidal matter extracted from the corn kernel occurred in the presence of sulphur dioxide. About 50% of the dry matter of the colloids (calculated as crude protein) consists of nitrogenous substances.

Test data show that some more high-molecular non-nitrogenous substances are extracted from the corn in the presence of sodium disulphite (= sodium pyrosulphite or sodium metabisulphite).

• 4 It has been found that the positive effect of lactic acid during evaporation of the extracts consists not only in the formation of soluble lactates, but also in the fact that the high molecular nitrogenous substances are degraded to low-molecular substances which do not precipitate during thickening of the extract.
• 5 Results of the technological testing of sodium disulphite showed that during the manufacturing of starch from corn it is possible to replace sulphur dioxide by this reagent in the steeping process according to the technological structure of the plant.

     

TECHNOLOGICAL FACTORS OF FLAVOUR STABILITY

The flavour stability of a beer primarily depends on the oxygen content of the bottled beer, but the individual steps of wort production are of similar importance viz:-

• (a) preservation of reducing substances by avoidance of oxygen pick-up during mashing, lautering and wort boiling.
• (b) elimination of substances which are prone to react to flavour active compounds like carbonyls by good mash and wort separation procedures,
• (c) avoidance of an excessive exposure of the wort to heat, to limit the formation of Maillard reaction products and related substances.

Existing brewhouses offer some possibilities to improve the process and thus flavour stability. For analytical control Gas Chromatography and High Performance Liquid Chromatography are excellent tools, even simple analyses help to avoid unwelcome changes in the day to day practice.     

Kriterien zur Qualitätsbeurteilung von Trockenkartoffelerzeugnissen für die menschliche Ernährung

Criterions to evaluate the quality of dried potato products for human consumption . The swelling properties of dried potatoes were tested. In the first part of this work the importance of starch and dry matter for the swelling behavior of dried potatoes is reported. To evaluate these experiments the correlation coefficient is used. 140 samples of dried potatoes were tested. Continuing the test series dried potatoes manufactured from one potato variety, what is devided into different classes of specific gravity were examined. The used physical conditions for estimating the swelling behaviour are the “swelling number” and the “rehydration value”. The central point of the second part is a theory to explain the phenomena of swelling for itself. This theory tries to answer the basic question how to influence the swelling behaviour of dried potatoes. The results of these experiments are interpertated by the postulation that two reaction typs estimate the swelling of dried potatoes:

• 1 The first reaction depends on the surface and is exothermic.
• 2 The second reaction does not depend on the surface and is endothermic.

     

Cyclodextrins in Pesticides

Many synthetic pesticides (herbicides, insecticides, fungicides, etc.) can be complexed with cyclodextrins. This “molecular encapsulation” frequently results in advantageous modifications of the properties of complexed substances.

• a) The hydrophilicity is strongly reduced, i. e. wettability, rate of dissolution and extent of solubility is enhanced, which generally results in enhanced bioavailability.
• b) Volatile, liquid, and gaseous substances, or substances of intolerable stink can be converted into microcrystalline, stable, well formulable substances.
• c) Incompatible substances can be mixed when at least one of the reacting components is complexed.
• d) The selectivity between herbivorous/non-herbivorous insects toxicity can be enhanced.
• e) CD-complexes are per se micronized substances, they are easily dispergable, no electric charging was observed.
• f) Long lasting effect can be ensured (e. g. in soil) because the complexed substances are released only on contacting with water.
• f) Cyclodextrins exert a direct auxin-like effect on plants therefore phytotoxic effect of pesticides can be reduced, etc.

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Some of the Minor Constituents of Wheat Starch and its Hydrolysates. Part II

• 1 Lipids were separated from wheat starch hydrolysates by centrifugation and purified by repeated centrifugation in warm acidulated water. Several amino acids were detected after further hydrolysis, and which represented 38% of the total nitrogen of the lipid. The free fatty acids had Iodine Value 96 (Hanus) and Acid Value 207.
• 2 After carbon and bentonite treatments under various conditions, syrups were evaluated by U. V. absorption analysis, total (Kjeldahl) and amino (Folin) nitrogen content, and heat resistance. The value of multiple treatment with each of these materials has been shown. Ion exchange treatments demonstrated that further improvements were possible with strongly basic and strongly acidic resins in their active forms.
• 3 An investigation of the kinetics of protein hydrolysis indicated that variations in the conditions of hydrolysis under practical conditions, for a given Dextrose Equivalent, would have only a slight bearing on the degree of protein hydrolysis. An evaluation of some syrups supported this theory.

     

Continuous Isomerization of Glucose to Fructose on a Commercial Basis

Immobilized glucose isomerase has been used to make more than 500,000 metric tons of high fructose corn syrups in the United States. These syrups have found wide application as high quality sweeteners to replace sucrose. A commercial process is described for the continuous enzymatic conversion of glucose to fructose. The use of immobilized glucose isomerase in a multiple bed reactor system is an economical method for making fructose. A comparison between immobilized glucose isomerase in a batch versus a continuous process shows the continuous process has the following advantages:

• 1 Lower enzyme usage and cost for converting glucose to fructose.
• 2 Lower capital equipment and labor costs.
• 3 Better and easier process control.
• 4 Lower refining costs and improved product quality.

Both the continuous isomerization process and the immobilization technique described are developments of Clinton Corn Processing Company, a Division of Standard Brands, Inc.     

ANALYTICAL EVALUATION OF α-ACIDS IN HOP EXTRACTS AND IN HOPS*

The results of new investigations on hop extract analysis are presented. The main findings are:

• 1 The specific extinction (257) of α-acids at 276 nm in iso-octane used at present in CCD and paper strip analyses is 3·5% too high: analytical results have therefore been too low. The new extinction value to be used is 248.
• 2 The result of paper strip analysis depends very much on the amount of α-acids placed on the strip. The three-point paper strip method can only partly correct this. In general, figures with paper strip analysis have a tendency to be too high.
• 3 Conductometric titration of α-acids produces a figure about 2 to 10% too low. This can be partly corrected by adding 20% dimethylsulphoxide or dimethylformamide to the titration medium.
• 4 Conductometric analysis of hop extracts with removal of “iso-α-acids like material” before titration is possible by a very simple procedure (pH 7 buffer extraction).

New photometric and conductometric procedures based on these results give figures which are in agreement for something which must be practically true α-acids.     

Reinigung und Verwertung von Abwässern der Kartoffelstärkeindustrie mit Hilfe von biologischen Kläranlagen

Purification and Utilization of Waste Water of Potato Industry by Means of Biological Clarification Plants. The importance of waste water pre-clearing in potato starch industry by means of a hig-grade separation of fruit water has been examined in both model and semi-technological scale. Observing the recirculation principle better economical as well as technical possibilities for biological purification of starch waste waters have been demonstrated by these investigations.

• 1 Starch waste waters which are extensively freed of fruit water can be profitable purified in fresh state as well as after storing in collection tanks in biological clarification plants.
• 2 Potato starch waste waters can be purified without difficulty in public clarification plants together with domestic waste waters.
• 3 By their contents of nitrogenic matter and P₂O₅ potato starch waste waters support the biological process in such waste waters, which are poor of these activating substances, i.e. waste waters of wood processing industry.

     

Feuchtebeständigkeit und Hydrolyseresistenz von Holz-zu-Holz-Bindungen in Spanplatten,hergestellt mit formaldehydarmen modifizierten Harnstoff-Formaldehydharzen unter Einsatz verschiedener Härtungsbeschleunigersysteme

In continuation of the work conducted in the first and second part of this series one-layer particleboards (pine wood) were made using three different low-emission UF-resins (UF1, UF2, UF4) and various amounts of different catalysts (ammonium sulfate, ammonium nitrate, a mixture of ammonium sulfate and formic acid). Melamine formaldehyde resin, resorcinol, quebracho-tannin and diphenylmethan diisocyanate (PMDI) were used as modifiers. The investigations led to the following results:

1. The use of ammonium nitrate as a catalyst led, compared with ammonium sulfate and the mixture from ammonium sulfate and formic acid, to higher mechanical properties and lower thickness swelling of the particleboards.
2. Particleboards bonded with resin UF1 modified with melamine formaldehyde resin showed, compared with the other investigated modifications, higher resistance in dry state, in the wet state and after water soaking and redrying of the particleboards. Also thickness swelling of these particleboards was lower.
3. Spraying PMDI prior to UF1 resin (preliminary spray method) improved the physico-mechanical properties of the particleboards (second place in the order of precedence after melamine resin).
4. Particleboards bonded with UF1 modified with resorcinol showed the lowest formaldehyde release, though this modification has a negative effect on the physico-mechanical properties of the boards.
5. Modification of UF1 with quebracho-tannin had an adverse effect on all properties of the particleboards.
6. Modification of the resins UF2 and UF4 during the condensation step of the resin led to similar effects on the properties of the particleboards as the modification by mixing modifier and resin prior to the application of the binder.

     

Die spezifische Drehung des Sorbits und des Sorbit-Molybdat-Komplexes

The Specific Rotation of Sorbitol and of the Sorbitol Molybdate Complex.

• 1 The specific rotation of the hexite at 365, 405, 436, 546 and 578 nm has been determined in solutions of different concentration with a commercial sorbitol preparation as well as with a self-produced sorbitol. Contents of both preparations had been determined enzymatically and by means of periodate. The specific rotation [α]_D was obtained mathematically from these data as well as by graphic extrapolation.
• 2 Conditions, under which the sorbitol molybdate complex shows its maximum of specific rotation were defined by systematic experiments at varying sorbitol, molybdate and hydrogen-ion concentration.
• 3) From these results a diagram was set up, which shows the molybdate and acid doses in order to determine sorbitol polarimetrically in the widest possible range.
• 4) The specific rotation of the sorbitol molybdate complex was determined at the same wavelengths as that of the sorbitol. It was also mathematically and graphically extrapolated for [α]_D.

     

Proliferation of and toxin formation by Staphylococcus aureus in skimmed and acidified milk as related to different heat treatments and incubation temperatures

This study was carried out in an attempt to minimize the total population of St. aureus in skimmed and acidified milk and henceforth to avoid the endotoxin formation in milk and milk products prior to manufacturing. Different heat treatments and incubation temperatures were used for normal and acidified milk. The following results were obtained:

• 1 The activated cells received a lethal effect. The surviving cells greatly depended upon incubation temperatures. The recovery was most suitable at low temperatures and it was relatively disturbed at higher incubation temperatures.
• 2 The lag phase continued for a long time prior to cell division.
• 3 The proliferation gave sigmoidal curves at all heat treatments.
• 4 A gradual decline was found in N-values. However, compared with those of the control, a high number of cell divisions took place at low incubation temperatures (25 and 30 °C). The rate of proliferation was low in all treatment cases.
• 5 The coagulase positive reactions showed great variations in time intervals. Low degree of firmness of blood plasma coagulation was obtained at incubation temperatures of 25, 30 and 45 °C, whereas the highest degree was obtained at 37 °C.
• 6 All above results were almost identical when experiments were performed on both acidified and normal milk with a pH 6.8.

     

ACTIVITY COEFFICIENTS of AROMA COMPOUNDS and WATER ACTIVITY IN MODEL SYSTEMS

One aim of this work was to measure the activity of water and aroma compounds in aqueous solutions simultaneously. The volatilities of aroma substances at infinite dilution in aqueous solutions of polyethylene-glycols (PEG) were studied. the activity coefficients (γi^∞) of volatile compounds were measured by gas stripping (exponential dilution). This dynamic method also allowed the measurement of the water activity of these solutions. the results showed that:

• 1 the influence of polyethylene-glycols on γi^∞ depended most strongly on the PEG mass fraction in the solution. the effect of the PEG molecular weight was not significant.
• 2 γi^∞ increased as molecular weight and length increased for the homologous series of alcohols tested. This can be explained by entropic effects. Probably, the same effect occurs for other homologous series.
• 3 γi^∞ for 2-propanone increased as temperature increased. Based on this relation, molar partial excess enthalpies of mixing were calculated for 2-propanone in an aqueous solution.

     

Residues of supona in sheep

Supona is a new organophosphorus compound which is highly effective for the control of maggot fly strike in sheep. Tissue samples taken from sheep which had been treated with various concentrations of Supona have been analysed for residues of Supona and the lipophilic metabolite trichloroacetophenone. As a result of treatment of sheep with concentrations of Supona at and above the intended field usage rate the following conclusions were drawn:

• 1 The Supona residues in the fat depots of sheep killed 7 days after dipping in double-strength dip wash never exceeded 0·1 ppm Supona and were in the main substantially below this level.
• 2 The residues in the major organs of these sheep were below the minimum detectable amount (0·003 ppm).
• 3 The residues of trichloroacetophenone in the body fats and organs of sheep treated with Supona were below the minimum detectable amount (0·001 ppm).
• 4 The residues of Supona in the body fat of sheep dipped in normal strength Supona dipwash and killed 3 days after treatment were less than 0·05 ppm.
• 5 The residues of Supona were considerably lower and much less persistent than those occurring with dieldrin when used at comparable concentrations.

     

Feuchtebeständigkeit und Hydrolyseresistenz von Holz-zu-Holz-Bindungen in Spanplatten,hergestellt mit formaldehydarmen modifizierten Harnstoff-Formaldehydharzen unter Einsatz verschiedener Härtungsbeschleunigersysteme

In continuation of the work conducted in the first part of this series one-layer pine wood particleboards were made using two different low-emission UF-resins (UF 1 and UF 2) using various amounts of different catalysts (ammonium chloride, ammonium sulfate, ammonium nitrate, a mixture of ammonium sulfate and formic acid) and tested regarding their properties. From the results the following conclusions can be drawn:

1. With increasing amount of catalyst in the range between 0.8% and 2.4% ammonium chloride and 0.8% and 3.2% ammonium nitrate the physical-mechanical properties of the boards deteriorated. In contrast, the formaldehyde release decreased with increasing amount of catalyst.
2. Compared with ammonium chloride ammonium nitrate led to higher mechanical properties and lowered thickness swelling of the boards.
3. Particleboards containing UF 1 as a binder showed, compared with those boards bonded with UF 2, higher mechanical properties and lower thickness swelling in water. However, the formaldehyde release of the boards bonded with UF 1 was above that of boards bonded with UF 2.
4. Particleboards bonded with UF 1 and UF 2 as a binder and containing ammonium nitrate as a catalyst showed, in general, the highest mechanical properties, those prepared with ammonium sulfate or a mixture of ammonium sulfate and formic acid as a catalyst the lowest.

     

Novel enzymatic synthesis of oligosaccharides

Industrial applications of enzyme catalysts are mostly hydrolysis reactions. But increasing attention is given to enzymatic synthesis reactions. The possibility of obtaining efficient synthesis reactions without involving costly cofactors is illustrated by examples taken in the field of oligosaccharide production.

Three main approaches are considered:

• reversion of hydrolysis reactions, by shifting the position of the reaction equilibrium,

• “transhydrolytic”; reactions, using the transferase activity of hydrolytic enzymes,

• transfer reactions, catalyzed by transferase enzymes.

The respective advantages and drawbacks of these three approaches are compared.

The oligosaccharides thus obtained are of interest in different fields of application: food and feed ingredients, pharmaceutical and immunological products, cosmetic additives, for example.     

Biochemisch-technologische Studien über die Naßverarbeitung von Mais 3. Mitteilung. Die Milieubedingungen im Maiskorn während des Quellprozesses

Biochemical-Technological Studies on Wet-Processing of Maize. Part 3. The Medium Conditions in the Maize Grain During the Steeping Process.

• 1 According to fundamental methodical examinations the destillation method with use of ground steeped corn is appropriate for the determination of SO₂ content in the interior of the maize grain.

As a result of the high buffering capacity of a maize-water suspension it is possible to judge pH-conditions in the interior of the grain during the steeping process by the pH-value determined in this medium.

• 2 During steeping by the single tank process at first a considerable amount of SO₂ is absorbed by maize components (the maximum after 10 hrs). Later, desorption symptoms begin to show according to the initial SO₂-concentration. The course of pH-values in the maize steeping-water gives reason to believe that at this stage SO₂ adheres to parts of the protein matrix that have become soluble. As a result of the entering SO₂, there occurs an intensive pH-decrease in the maize grain. Near the end of the process, values in both maize steeping-water and maize grain get very close without reaching full identity. Initial SO₂-values of 0,4 % and more inhibit lactic acid bacteria.
• 3 In a technological counter-current process two steeping phases can be distinguished. During the first phase – from the beginning up to the 40th hour – the SO₂ content in the maize steeping water and in the steeping maize increases unnoticeably, but the formation of lactic acid takes place (maximum between 12th and 28th hour). At a certain steeping condition the produced lactic acid can enter the interior of the grain and cause a decrease of pH-value. The second, shorter phase is characterized by intensive SO₂ increase and pH decrease in both maize steeping water and maize. The lactic acid content as well as its new formation are low. The proteindesintegrating effect of the steeping agent, the determining factor for the further processing of the maize, becomes effective at a late stage of the process.
• 4 The lactic bacteries as well as their products of metabolism can enter themselfs in the interior part of the grain, provided that the bacteria concentration in the aqueous medium is high and a certain level of maize stepping is reached. As the portion of the relatif bacterial activity in the grain liquid is 70 % in relation to the maize steeping water, a proteolytic activity of the bacterial enzymes is possible.

     

La caractérisation des amidons eu égard à leurs utilisations industrielles en particulier dans l'industrie textile et papetière

Characterization of Starches with Respect to their Application in the Industry, especially in the Textile and the Paper Industry. After a short review of the economical importance of starch in the textile and the paper sector the author shows how he characterizes the industrial starches: water content (after the French Standard AFNOR V. 03602), microscopic examination (normal and polarized light, phase contraste, 100 × or 250 × magnification), nitrogen content (Kjeldahl), ash content (AFNOR V. 03605), color, pH-value of water extract, and particulary rheological behaviour. At this point the following is accentued:

• 1 Starch/water systems are not true Newtonian. They have not one viscosity alone but an infinity of apparent viscosities in relation with the rheological conditions. To give one value even in arbitrary units without precise informations about shear rate and shear stress is meaningless.
• 2 The preparation of the starch paste is a multiphenomene and needs a non-laminar stirring. That means that it is illusive to obtain reproducible torque value by rotation at constant speed from one apparatus to another.
• 3 Only rheometers with coaxial cylinder permit an absolute characterization of the before prepared starch/water system.