Steeping of Poor Quality Wheat. Effects on Physicochemical Properties and Functional Characteristics of the Starch

Wheat of poor baking quality was steeped at temperatures ranging from 5° to 50°C, prior to starch isolation. Physicochemical properties of starch – susceptibility to α-amylase, Amylograph viscosity, and solubility in dimethylsulfoxide – and functional properties – bread and cake baking performance and thickening power – were determined. Starch yield increased as the steeping temperature increased. The susceptibility of starches to α-amylase increased significantly as the steeping temperature of grain increased above 40 °C. Amylograph consistency of starches increased due to temperature of steeping. Increasing the steeping temperature of grain increased starch solubility in dimethyl sulfoxide. Bread baking performance of starches was not significantly affected by the various treatment temperatures and bread of satisfactory quality was obtained. Cakes of very good characteristics were produced with all starches. The thickening power of starches in fillings stored at room and refrigeration temperatures was higher initially for starches isolated at higher temperature. The consistency decreased upon storage in all fillings. Starch with acceptable functional properties could be obtained from a wheat of poor baking quality.     

Phytate content is reduced and β‐glucanase activity suppressed in malted barley steeped with lactic acid at high temperature

The effect of different steeping conditions on phytate, β‐glucan and vitamin E in barley during malting was studied by a full factorial experiment with three variables (steeping temperature, barley variety and steeping additions). Addition of lactic acid to the steeping water induced a reduction of phytate during steeping and germination, especially in combination with the high steeping temperature (48 °C). Furthermore, lactic acid and high temperature steeping inhibited β‐glucanase development, resulting in a well‐preserved β‐glucan content after germination. When steeping was conducted without addition of lactic acid, the low steeping temperature (15 °C) promoted development of both phytase and β‐glucanase activity during germination. A slightly higher level of tocopherols and tocotrienols was observed in samples steeped at 15 °C than in samples steeped at 48 °C. However, addition of lactic acid reduced the amount for both temperatures. When lactic acid bacteria were added to the steeping water none of the parameters studied differed from samples steeped with water only. The results show the possibility of combining phytate degradation with a preserved β‐glucan content during malting and can thus be of interest for development of cereal products with improved nutritional value. Copyright © 2004 Society of Chemical Industry     

Steeping of Barley Starch. Effects on Physicochemical Properties and Functional Characteristics

Starches isolated from 3 barley varieties (Glacier, High-amylose Glacier, Waxy Compana) were steeped at 25°, 40° and 50°C for 1 and 3 days. Enzyme susceptibilities, water binding capacities, swelling powers, solubilities and gelatinization temperatures were determined. The extent of change in physicochemical properties due to steeping varied with type of barley starch. Generally, gelatinization temperature increased and the range narrowed as the temperature and the duration of incubation at a specific temperature increased. Swelling power was inversely related while solubility was directly related to amylose content. The treatment had little effect on swelling powers but restricted solubilities. Steeping of Glacier and Highamylose Glacier barley starches produced a more pronounced V-pattern indicating increased amylose-lipid interaction. Cakes baked with Glacier barley starches treated at 25° and 40°C up to 3 days were acceptable; starch treatment at 50°C caused collapse of cakes. Starch treatment caused high initial consistencies of fillings which were reduced during storage.     

The Influences of Steeping Duration and Temperature on the α‐ and β‐Amylase Activities of Six Thai Rice Malt Cultivars (Oryza sativa L. Indica)

A preliminary study of malting conditions for six Thai rice cultivars was conducted. Three non‐glutinous rice cultivars (KDML105, PT60, and WR) and three glutinous rice cultivars (SPT, RD6, and KND) were selected. The steeping durations (24, 48, and 72 h) and temperatures (20, 25 and 30°C) were investigated for their effect on α‐ and β‐amylase, the key enzymes for malt quality evaluation. During steeping, the production of both enzymes was lower than at the germination process. The longer the steeping duration, the lower the maximum β‐amylase activity obtained. The contradictory effect was observed for α‐amylase activity, near the end of the germination time. Additionally, temperature influenced the water absorption content as well as the amylolytic enzyme activity. Particularly at 30°C, the maximum β‐amylase activity (6.7 unit/mg protein) was found in KND malt steeped for 24 h, and maximum α‐amylase activity (20 unit/mg protein) was found in PT60 malt steeped for 72 h. The amount of enzyme production depended on the variety rather than the amylose content in the rice. The optimal condition for malting rice regarding β‐amylase activity and α‐amylase activity was analyzed at 30°C, with steeping for 24 h and germination for 4–5 days.     

Effect of ground corn steeping on starch properties

Pasting and thermal properties, and microstructure of starch from ground corn (GS) steeped at 52 °C in sulphurous acid solution (0.20%) at different steep times (8, 16, 24, 32 and 40 h) were investigated. The isolated starch obtained by wet milling was characterised by determining pasting properties in Rapid Visco Analyser (RVA), retrogradation enthalpy in differential scanning calorimetry (DSC), and microstructure of granules in light (LM) and scanning electron microscopy (SEM). Milling before steeping and long steep time caused reduction in peak, hot paste, cool paste, breakdown and setback viscosities. Steep time provoked an increase in the retrogradation temperatures (onset and peak), whereas no significant differences were found in retrogradation enthalpy. Microstructure characteristics analysed by SEM showed many cracks and cavities on surface in samples steeped 8 h, whereas samples steeped 40 h showed a great alteration and disruption of their inner layer. LM with polarised light confirmed that starches retained birefringence with several differences depending on the steep time. The use of ground kernels allowed a better steep solution–endosperm interaction, which caused changes in rheological, thermal and microstructural starch characteristics.     

Effects of malting on β‐glucanase and phytase activity in barley grain

The effects of malting on β‐glucan and phytate were investigated in one naked and one covered barley by a full factorial experiment with three factors (steeping temperature, moisture content and germination temperature) each with two levels. Analysis of total content of β‐glucan in the malted samples showed small changes after steeping at the high temperature (48 °C), while steeping at the lower temperature (15 °C) gave a significantly lower content. This trend was even stronger for β‐glucan unextractable at 38 °C. Analysis of the activity of β‐glucanase for the samples steeped at 15 °C showed a strong increase over the time of germination, while those steeped at 48 °C had a much slower development. The other two factors influenced the outcome to a small extent, mainly because the steeping temperature was the most important factor overall where any changes in β‐glucan and β‐glucanase were observed. When β‐glucan was extracted at 100 °C, a larger yield was obtained, and this was influenced by the steeping temperature in a much stronger way than for β‐glucan extracted at 38 °C. Determination of average molecular weight for β‐glucan extracted at 100 °C gave a lower value for samples steeped at 15 than at 48 °C. The design did not have any large effects on phytate degradation and phytase activity. However, it indicated that selective control of the enzymes might be possible, since phytase activity was barely affected by the parameters studied, while β‐glucanase was heavily affected. © 2002 Society of Chemical Industry     

Methods for accelerating malting,a small scale investigation

It was confirmed that steeping fully after-ripened barley at 25° or 30°c, for various periods, induces different degrees of ‘water sensitivity’. Germination of such warm-steeped grain, set to grow at the steeping temperature, was maximal when the moisture content was about 35%. Sprays of hydrogen peroxide, applied immediately after draining the steeped grain, accelerated the subsequent germination of warm-steeped barley when grown at elevated temperatures. Exceptionally rapid steeping/germination schedules were elaborated, using micromalting techniques. For example, fully mature grain was steeped, (7 h 25°c) to a moisture content of about 36%. All subsequent processing was also at 25°c. After a drain (2 h) the grain was sprayed with a solution of gibberellic acid (0·25 mg/kg) in a dilute solution of hydrogen peroxide (2·5 vol.). Spraying with water was carried out twice more during the germination period to increase the moisture content of the barley to about 44%. The grain was set to kiln at 43°c, 48 h from steep out, that is 55 h from first wetting. Kilning conditions were chosen to allow maximal survival of enzymes. The malt had a hot water extract above 103 lb/Qr (fine grind, on dry matter) and was made at the expense of a 7·5% malting loss. It was acceptable by other analytical criteria. If the second water spray was replaced by a spray of a dilute solution of sulphur dioxide (400 mgjkg) a malt having an extract of 103·5 lb/Qr was obtained with a malting loss of 5·8%, but yielding more soluble nitrogen. The possibility of achieving even shorter processing times, by working at 30°c, was noted.     

Influence of Steeping Solution and Storage Temperature on the Color Change of Garlic

ABSTRACT:  The objective of this study was to investigate the browning of garlic under different steeping conditions and storage temperatures. The brown indices of steeped garlics showed lowest values (7.3 and 7) in 25% and 50% EtOH at 7 d of storage. The degree of browning of steeped garlics was lowest (10.2 in 25% EtOH and 10.4 in 50% EtOH) in the samples soaked for 8 h at 13 d of storage. As the storage temperature was increased from 10 to 40 °C, the brown indices of garlics revealed an increasing trend relative to storage time regardless of steeping treatment. Overall, the kinetic parameters showed relatively low  R ² and irregular reaction constants, but the  k_o  values showed an increasing trend with temperature under a zero-order model. The highest polyphenol content within the garlic bulbs was seen in controls (without steeping treatment, 588.9 μg/g), than 0% EtOH (water, 392.5 μg/g), than 25% EtOH (211.3 μg/g), and finally 50% EtOH (155.6 μg/g). The polyphenol oxidase activity of garlic showed a similar trend to that of polyphenol content. However, the texture properties of garlics steeped with 25% and 50% did not change.
Practical Application: The garlic color preferred by consumers is a creamy-white, but this is susceptible to enzymatic browning when pre-peeled and chopped. When garlic was steeped in the 25% and 50% alcohol, the browning of garlic was prevented during storage.     

Steeping of Starch at Various Temperatures-Effects on Functional Properties

Functionality of wheat starches steeped at various time and temperature conditions was studied in bread, cake and pie filling systems. Treatment at 50°C reduced the bread volume. Crumb softness in breads increased with duration and temperature of the treatment. Addition of 3–10% (flour basis) treated starch (40°C for 3 days) reduced firmness of breads. Cakes with starches treated at 25°C and 40°C up to 3 days were acceptable; starch treatment at 50°C caused collapse of cakes. The consistencies of pie fillings are increased by starch treatment at 25°C. Starches treatment at higher temperatures (40–50°C) caused high initial consistencies of fillings which were reduced during storage.     

Laboratory Wet‐Milling of Grain Sorghum With Abbreviated Steeping to Give Two Products

Short‐time and no‐time steeping were used in the wet‐milling of grain sorghum to give two products, starch in over 78% recovery (starch basis) plus the remaining grain solids. In the wet‐milling process 1.5 parts of fresh water were used per part of grain to compensate for drying and transfer losses. Starting with 100 g (dry solids) of commercial No.2 grain sorghum, steep time (1—3 h), steep temperature (25—60 °C), and coarse‐grinding speed (7, 500—12, 500 rpm with tip speed of 90.4—150.7 km/h) were varied in a model study; starch recovery, starch lightness (L*), and damaged starch were the responses. Grain sorghum was steeped with twice its weight of process water containing 0.2% sulfur dioxide and the steeped kernels were added to an equal volume of process water and the mixture was ground for 6 min in a Waring blender with blunt blades (d = 3.2 cm). The course‐ground material was sieved (opening 1190 μm) to collect the bran/germ, and the throughs were allowed to stand. The sedimented phase was finely ground by one pass through a plate mill, and the fine fiber removed by sieving (opening 73 μm). The slurry was adjusted to a specific gravity of 1.04, and the starch was separated from the protein fraction on a starch table. The protein fraction was combined with the steep‐liquor concentrate (54% solids) plus the bran/fiber and the fine‐fiber fractions to give the co‐product, which contained 70% moisture (wet basis, wb) and 27% protein (dry basis, db). In the surface response study, recovery of starch ranged from 57 to 89%, starch protein content from 0.4 to 0.5%, and lightness (L*) from 90 to 93. Damaged starch content was constant at around 0.4%. Commercial grain sorghum gave the highest starch recovery (90%) after steeping 2 h at 55 °C and coarse‐grinding at 10, 500 rpm; whereas a food‐grade, a white and a red sorghum gave 85, 84, and 80% recoveries, respectively. The four starches had lightness (L*) values of 93—94 and damaged starch contents of 0.4—0.6%. When the commercial grain sorghum was wet‐ground without steeping in 2 parts of water containing 0.2% sulfur dioxide, a 78% recovery of starch was obtained with L* 93.7 and starch damage 0.5%.     

Effect of Protease Addition on Starch Recovery from Steeped Sorghum and Maize

The effect of protease addition on starch recovery from steeped white regular sorghum (RSOR) compared to yellow maize (YMZ) was determined. An in vitro wet milling method standardized to test dosages from 0 to 1.5 Anson units (AU/100 g grain) indicated that starch yields increased proportionally as enzyme concentration increased. The yields were significantly lower for RSOR. A factorial experiment with a level of confidence of P < 0.05 was performed to study the effect of protease addition (1.25 AU/100 g grain) to coarsely ground kernels for 4 h after 20 h or 44 h SO₂ steeping of whole grains. Calcium oxide (CaO) was used to increase the pH of the steep solution to 5.5 and improve enzyme activity. The in vitro and laboratory tests indicated that the enzyme treatment significantly improved starch yields and recoveries; the effect being more pronounced in RSOR. Protease‐treated kernels yielded 3.2% more starch than those steeped regularly. RSOR steeped for 20 h and then treated with the enzyme for 4 h yielded 6.7% more starch than the counterparts steeped regularly. When steep times were compared, kernels soaked regularly for 48 h produced 1.6% more starch than counterparts steeped for 24 h. The protease treatment reduced the amount of inseparables (gluten‐starch complexes) to zero and also lowered the gluten content of starch by about 1.5%. A comparison of protein and ash contents for the refined starches indicated that the process was more efficient for YMZ than for RSOR and for grains steeped regularly for 48 h. YMZ starch started gelatinization at a lower temperature, required less time to reach peak viscosity and had less shear thinning than RSOR.     

Rheological characterization of corn starch isolated by alkali method

The pasting properties of alkali-isolated corn starches obtained from corn grits, as well as the rheological behaviour of their 8% gels were investigated. The alkali isolation was performed using different conditions concerning alkali concentration (0.15% and 0.30%), steeping time (30 min and 90 min) and temperature (25 °C and 50 °C).Alkali-isolated starches exhibited lower pasting temperatures and higher peak viscosities than the wet-milled starch. With respect to the steady shear measurements, alkali starch gels showed higher viscosities and greater extent of thixotropy.Changes in alkali isolation conditions did not influence the changes in gelatinization and peak temperature values. On contrary, peak viscosity was significantly influenced by these factors. Steady shear, as well as dynamic shear tests, showed that gels formed from starch isolated using higher alkali concentration were stronger than those obtained from starch isolated at lower alkali concentration. However, isolation at higher steeping temperature and longer steeping time resulted in starch with weak gel-like behaviour.     

Phytochemical profiles and antioxidant capacities of white and red ginseng as affected by marinating media (vinegar,yellow wine,and Chinese liquor)

Marinating ginseng is popular practice at home and being applied to industrial manufacturing in China. However, knowledge on the effects of steeping media on antioxidant capacity of ginseng is limited. Hair root, sliced, powdered, ultrafine ground white and red ginseng were marinated with 3.5° and 9° vinegar, yellow wine, and 53° Chinese liquor. Total phenolic content (TPC), total flavonoid content (TFC), DPPH free radical scavenging capacity (DPPH), ferric reducing antioxidant power (FRAP), ABTS free radical scavenging capacity, and total saponin content (TSC) of the steeped liquid were measured with colorimetric methods. Among four marinating media, Chinese liquor is the most favorable medium since most of the indicators showed obvious higher values. It was noticed that TFC and TSC of white ginseng hair root steeped liquid by Chinese liquor were extremely higher than others. The results indicate that Chinese liquor is the most desirable medium for ginseng steeping.

Practical applications

Presented information will guide consumers to choose ginseng materials and steeping methods to obtain desired health benefit components. The study will also help food manufacturers and alcoholic beverage industry to understand how steeping medium affect the bioactive food components.     

L -半胱氨酸与发酵酸浆协同作用优化玉米湿磨工艺

为了改进玉米湿磨工艺,采用L-半胱氨酸替代传统浸泡工艺中的SO2,降低传统玉米淀粉生产过程中由SO2浸泡引起的环境污染。在具有絮凝活性的副干酪乳杆菌副干酪亚种L1发酵液制成的玉米酸浆中加入L-半胱氨酸,浸泡玉米碎粒,浸泡一定时间后加水磨浆,过筛除去纤维等杂质,淀粉在具有絮凝活性的副干酪乳杆菌副干酪亚种L1的作用下迅速沉降。通过改变酸浆的用量、L-半胱氨酸用量、浸泡温度、浸泡pH值、浸泡时间和菌种接入量,考察各因素对浸泡液中可溶性蛋白质的增量和淀粉提取率的影响,并采用响应面法确定最佳湿磨工艺。结果表明：最佳工艺参数为浸泡时间48 h、L-半胱氨酸质量浓度1.5 g/100 mL、浸泡pH 7、自然发酵酸浆用量比（m（玉米粒质量）∶V（酸浆体积））1∶4、浸泡温度30 ℃,此条件下淀粉提取率的最大值为93.21%。     

Effects of Heating,Vacuum Drying and Steeping on Gelatinization Properties and Dynamic Viscoelasticity of Various Starches

Starches having A‐ and B‐type X‐ray diffraction patterns (A‐ and B‐type starches) were modified by heating at 120 °C for 2 h (HT), vacuum drying at room temperature for 20 h (VD) and steeping at 50 °C for 20 h (ST). The properties of starches were compared using differential scanning calorimetry (DSC) and dynamic viscoelasticity behavior during heat processing (G' behavior). As observed by DSC, HT rarely changed the gelatinization properties for A‐type starches, but decreased the gelatinization temperatures and enthalpies (ΔH) for B‐type starches. A shift of the X‐ray diffractograms from B‐type to A‐type patterns was not detected after HT. Similar changes in gelatinization properties were observed for B‐type starches after VD. ST increased the gelatinization temperatures and also narrowed the gelatinization temperature range irrespective of crystal type. Both HT and VD decreased the peak temperature (T_p) in G' behavior and increased the peak G' value for B‐type starches. ST increased T_p and also decreased the peak G' value irrespective of starch crystal type. G' values after reaching T_p — which indicate the viscoelasticity of the swollen starch granules without breakdown — showed significant increases only for B‐type starches after HT.     

MICROMALTING TRITICALE

A sample of ‘Lasko’ triticale, a wheat × rye hybrid cereal, was micro-malted in a variety of ways. The grain was adequately steeped in under 24 h, and was relatively unaffected by high steeping temperatures, or the use of air-rests. Malts with exceptionally high extracts (about 340 1°/kg dry) and diastatic powers were obtained with malting losses of about 8% after 4 days germination. However, levels of soluble nitrogen were also high, even when potassium bromate had been employed. Malts made from this cereal could be of value in mixed brewing grists and in the manufacture of some malt extracts.     

Kinetics investigation of antioxidant capacity and total phenols of low‐temperature steeping Bi Luo Chun green tea

Traditionally, tea is steeped in boiled water in Taiwan. In this study, Bi Luo Chun (250 μg mL^?1) steeped at 4, 22, 30, 40 and 50 °C reached the saturation of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity at the time of 15, 8, 2, 0.17 (10 s) and 0.17 min (10 s), respectively. The result indicated that tea steeped in cold water (under 22 °C) still can reach a saturation of antioxidant capacity in 15 min. However, the initial scavenging rate (% min^?1) was quick and decreased with time at all steeping temperatures (r: ?0.98 to ?1.00). Total phenols and the DPPH scavenging capacity of Bi Luo Chun showed excellent correlation with time. However, the plot of DPPH scavenging capacity vs. total phenols was not always correlated. The result indicated that polyphenol infusion at different times may have a different DPPH scavenging capacity.     

纤维素酶对玉米淀粉生产中浸泡效果的影响

本研究通过使用纤维素粗酶制剂对湿法生产玉米淀粉的浸泡工艺的影响进行了研究,结果表明,纤维素粗酶制剂能够显著地缩短玉米淀粉生产的浸泡时间,降低了二氧化硫的使用浓度,在0.1%的二氧化硫浓度的浸泡液中添加0.3%纤维素粗酶制剂,作用时间为12h,其淀粉得率为57.0%,而使用传统的逆流法工艺(实验室模拟)浸泡48h的淀粉得率仅为54.1%。     

Optimizing red sorghum malt quality when Bacillus subtilis is used during steeping to control mould growth

Previous work has shown that Bacillus subtilis‐S499‐based biocontrol treatments applied without aeration at the steeping stage of red sorghum malting offer good mould reduction, but yield malts with low levels of key hydrolytic enzymes. Thus we attempted to raise these levels by aerating the steeping liquor, varying the steeping time (from 8 to 40 h) and temperature (from 25 to 35 °C), and combining a biocontrol treatment with prior steeping in 0.2% NaOH. Aeration proved particularly important whenever B. subtilis cells were present in the steep liquor. The optimal temperatures for α‐ and β‐amylase were 30 and 25 °C, respectively. By increasing the steeping time, it was possible to improve the α‐amylase activity, but the β‐amylase activity peaked sharply between 16 and 20 h, depending on the steeping medium. A good compromise was steeping in a biocontrol medium for 14–16 h at 30 °C. Combination steeping treatments (0.2% NaOH for 8 h followed by biocontrol for 8 h) yielded malts of a quality approaching that afforded by dilute alkaline treatment. Copyright © 2012 The Institute of Brewing & Distilling     

Effects of time/temperature treatments on potato (Solanum tuberosum) starch: a comparison of isolated starch and starch in situ

Previously, time/temperature treatments of starch have been performed mainly on starch/water systems. In this study the same time/temperature treatments were applied to starch/water systems and to potato starch in situ. Two potato varieties (Solanum tuberosum cultivars Asterix and Bintje) were used. The effect of time/temperature treatments on gelatinisation behaviour was evaluated using differential scanning calorimetry (DSC). A blanching process was simulated by heating samples to 74 °C and then cooling them to 6 °C. A DSC scan showed that starch was completely gelatinised after this treatment. Retrogradation of amylopectin increased during storage at 6 °C from 0 to 24 h after blanching. Annealing of starch, with the aim of altering cooking properties, was performed by heating samples to temperatures below the gelatinisation onset temperature. Treating samples at 50 °C for 24 h caused a shift in gelatinisation onset temperature of 11–12 °C for isolated starch and 7–11 °C for in situ samples. The extent of the annealing effect depended on the difference between onset and annealing temperatures, and prolonged treatment time increased the effect. Starch/water systems and tissue samples behaved similarly when exposed to time/temperature treatments. The most apparent difference was the shift of gelatinisation to higher temperatures in tissue samples. Copyright © 2003 Society of Chemical Industry