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1.
Gels ; 10(6)2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38920897

RESUMO

The functional characteristics of starch can be altered by shear force, which makes the impact on its microstructure of great importance to the food industry. This study investigated the effects of freeze-drying on the gel texture, pasting capabilities, and swelling power of starches made from sweet potatoes (SP), chickpeas (CP), and wheat (WS) combined with Cordia (CG) and Ziziphus gum (ZG). The samples were annealed in water without shearing and in a rapid visco-analyzer (RVA) for 30 min at 60 °C while being spun at 690 rpm. Both native and freeze-dried samples were mixed with 1% or 3% ZG and CG. After annealing, the starches were examined using a texture analyzer and RVA. The results showed that freeze-drying had a substantial (p > 0.05) impact on the starch granule, in addition to the effect of annealing. The peak viscosity of freeze-dried native CP and SP starches increased, but the peak viscosity of freeze-dried wheat starch decreased. The setbacks for CP and WS increased, whereas the setbacks for SP varied slightly. Furthermore, it was demonstrated that annealing in an RVA exhibited a substantially lower peak viscosity than annealing in a water bath; the RVA's shearing effect may have been the cause of this difference. Cordia gum fared better than ZG in terms of peak viscosity, although ZG significantly reduced setback in comparison to CG. Among the various blends, the native WB sample had the lowest hardness (100 ± 4.9 g), while the freeze-dried WB SP sample had the greatest (175.5 ± 4.8 g). Shearing of starches broke up the granules into smaller pieces, which made them gel at lower temperatures. This could be a good thing when they are needed for food uses that require little cooking.

2.
Molecules ; 28(20)2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37894509

RESUMO

Starches from different botanical sources are affected in the presence of enzymes. This study investigated the impact of α-amylase on several properties of pre-gelatinized starches derived from chickpea (Cicer arietinum L.), wheat (Triticum aestivum L.), corn (Zea mays L.), white beans (Phaseolus vulgaris), and sweet potatoes (Ipomoea batatas L.). Specifically, the water holding capacity, freezable water content, sugar content, and water sorption isotherm (adsorption and desorption) properties were examined. The source of α-amylase utilized in this study was a germinated sorghum (Sorghum bicolor L. Moench) extract (GSE). The starch samples were subjected to annealing at temperatures of 40, 50, and 60 °C for durations of either 30 or 60 min prior to the process of gelatinization. A significant increase in the annealing temperature and GSE resulted in a notable enhancement in both the water-holding capacity and the sugar content of the starch. The ordering of starches in terms of their freezable water content is as follows: Chickpea starch (C.P.S) > white beans starch (W.B.S) > wheat starch (W.S) > chickpea starch (C.S) > sweet potato starch (S.P.S). The Guggenheim-Anderson-de Boer (GAB) model was only employed for fitting the data, as the Brunauer-Emmett-Teller (BET) model had a low root mean square error (RMSE). The application of annealing and GSE treatment resulted in a shift of the adsorption and desorption isotherms towards greater levels of moisture content. A strong hysteresis was found in the adsorption and desorption curves, notably within the water activity range of 0.6 to 0.8. The GSE treatment and longer annealing time had an impact on the monolayer water content (mo), as well as the C and K parameters of the GAB model, irrespective of the annealing temperature. These results can be used to evaluate the applicability of starch in the pharmaceutical and food sectors.


Assuntos
Ipomoea batatas , Sorghum , Grão Comestível , Amilose , Amido , alfa-Amilases , Água , Açúcares , Extratos Vegetais
3.
Molecules ; 27(21)2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36364040

RESUMO

Acacia (AG) and cactus gums (CG) were mixed into wheat flour at the 3% and 6% levels. The flour blends were tested for their pasting, dough development, and extensibility behaviors. The blends were used to make cookies, which were then evaluated for their physical, textural, and sensory qualities. Both types of gum reduced the setback viscosities, water absorption, and farinograph quality numbers while increasing the water retention capacity, dough development time, and extensibility. The thickness and diameter of the cookies decreased in the presence of the cactus gum, while the acacia gum resulted in greater thickness and diameter. The addition of more gums increased the hardness of the cookies while decreasing their fracturability. All the cookie types were acceptable for all the sensory attributes studied. When compared to the control, the panelists preferred the color of the cookies with a higher level of gum. Overall, the presence of gums in the formulation resulted in the development of cookies with improved technological and sensory attributes. Likewise, the cookies with higher levels of gum can deliver 6% more soluble fiber without compromising their overall acceptability.


Assuntos
Acacia , Fabaceae , Opuntia , Farinha , Triticum , Fibras na Dieta , Água
4.
Molecules ; 27(10)2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35630544

RESUMO

The influence of 2% and 5% Cordia (CG) and Ziziphus (ZG) gums on dough characteristics and cookie quality was investigated. Micro-DoughLab, a texture analyzer (TA), a rapid viscoanalyzer (RVA), and solvent retention capacity were used to examine the effect of CG and ZG gums on dough physicochemical parameters (SRC) and cookie quality. The diameter, thickness, spread, and sensory evaluation of cookies were evaluated. With the addition of CG and ZG, dough softness, mixing time, and mixing tolerance index (MTI) increased, whereas stability and water absorption decreased. TA data showed that adding gums resulted in softer and less sticky doughs than the control, whereas RVA data showed that adding CG resulted in a significant increase in peak viscosity, but no change in flour gel setback. In comparison to the control and CG samples, the ZG samples exhibited the most dough extensibility. The thickness and diameter of the cookies increased but the spread decreased, due to the added gums. The gum-containing cookies had a lower overall acceptability by panelists than the control, although only by a small margin. Gum-containing cookies, on the other hand, can deliver up to 5% soluble fiber.


Assuntos
Cordia , Ziziphus , Fenômenos Químicos , Farinha , Reologia
5.
Foods ; 11(9)2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35563930

RESUMO

Two hydrocolloids, acacia gum and cactus gum, were tested in the current study to see if they could improve the quality of the dough or have an effect on the shelf life of pan bread and sponge cake. Both gums considerably (p < 0.05) enhanced the dough development time, softness, and mixing tolerance index while decreasing the water absorption. Although the dough was more stable with the addition of acacia gum than with cactus gum, the control sample had the highest peak, final, breakdown, and setback viscosities. Acacia gum, on the other hand, resulted in a higher wheat-flour-slurry pasting temperature (84.07 °C) than cactus gum (68.53 °C). The inclusion of both gums, particularly 3%, reduces the gel's textural hardness, gumminess, chewiness, springiness, and adhesiveness. Lightness (L*) and yellowness (b*) were both increased by the addition of acacia gum to bread and cake, whereas the addition of cactus gum increased both color parameters for cakes. The use of acacia gum increased the bread and cake's volume. Cactus gum, on the other hand, caused a decrease in bread hardness after 24 h and 96 h. The cake containing acacia gum, on the other hand, was the least stiff after both storage times. Similarly, sensory attributes such as the crumb color and overall acceptability of the bread and cake were improved by 3% with acacia gum. For these and other reasons, the addition of cactus and acacia gums to bread and cake increased their organoleptic qualities, controlled staining, and made them softer.

6.
Food Chem ; 388: 132988, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35447594

RESUMO

Acetylated corn starch was used as a fat replacer in beef patties and its effect on the physicochemical, textural, and sensory attributes of the patties was assessed during frozen storage (-20 °C) for 60 days. The results showed that acetylated corn starch enhanced the redness, moisture retention, thickness, and sensory attributes of the patties (P ≤ 0.05). It also reduced the firmness, cooking loss, diameter reduction rate, and dimensional shrinkage of the patties (P ≤ 0.05). The patties contain 15% acetylated corn starch showed a microstructure similar to that contain 15% animal fat as examined by scanning electron microscopy. Patties containing acetylated corn starch showed high scores of physicochemical properties and sensory attributes, which revealed the beneficial use of this modified starch in meat industry. In conclusion, acetylated corn starch improved the physicochemical properties and sensory attributes of beef patties and can thus be used as fat replacer in meat products.


Assuntos
Produtos da Carne , Amido , Animais , Bovinos , Culinária , Carne , Produtos da Carne/análise , Zea mays
7.
Molecules ; 27(3)2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35163967

RESUMO

This study was planned to explore the locally available natural sources of gum hydrocolloids as a natural modifier of different starch properties. Corn (CS), sweet potato (SPS), and Turkish bean (TBS) starches were mixed with locally extracted native or acetylated cactus (CG) and acacia (AG) gums at 2 and 5% replacement levels. The binary mixtures (starch-gums) were prepared in water, freeze dried, ground to powder, and stored airtight. A rapid viscoanalyzer (RVA), differential scanning calorimeter (DSC), texture analyzer, and dynamic rheometer were used to explore their pasting, thermal, textural, and rheological properties. The presence of acetylated AG or CG increased the final viscosity (FV) in all three starches when compared to starch pastes containing native gums. Plain SPS dispersion had a higher pasting temperature (PT) than CS and TBS. The addition of AG or CG increased the PT of CS, SPS, and TBS. The thermograms revealed the overall enthalpy change of the starch and gum blends: TBS > SPS > CS. The peak temperature (Tp) of starches increased with increasing gum concentration from 2 to 5% for both AG and CG native and modified gums. When compared to the control gels, the addition of 2% CG, either native or modified, reduced the syneresis of starch gels. However, further addition (5% CG) increased the gels' syneresis. Furthermore, the syneresis for the first cycle on the fourth day was higher than the second cycle on the eighth day for all starches. The addition of native and acetylated CG reduced the hardness of starch gels at all concentrations tested. All of the starch dispersions had higher G' than G″ values, indicating that they were more elastic and less viscous with or without the gums. The apparent viscosity of all starch gels decreased as shear was increased, with profiles indicating time-dependent thixotropic behavior. All of the starch gels, with or without gums, showed a non-Newtonian shear thinning trend in the shear stress vs. shear rate graphs. The addition of acetylated CG gum to CS resulted in a higher activation energy (Ea) than the native counterparts and the control. More specifically, starch gels with a higher gum concentration (5%) provided greater Ea than their native counterparts.


Assuntos
Fabaceae/metabolismo , Ipomoea batatas/metabolismo , Zea mays/metabolismo , Acacia , Coloides , Fabaceae/crescimento & desenvolvimento , Goma Arábica/metabolismo , Ipomoea batatas/crescimento & desenvolvimento , Opuntia/metabolismo , Gomas Vegetais , Reologia/métodos , Arábia Saudita , Amido/metabolismo , Temperatura , Termodinâmica , Viscosidade , Zea mays/crescimento & desenvolvimento
8.
Foods ; 11(3)2022 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-35159610

RESUMO

The functionality of hydrocolloids of different origins, gum Cordia (GC), and gum ziziphus (GZ) on pan bread and sponge cake quality and their potential use in retarding the staling process have been studied. The effects of the gums were determined by assessing the pasting qualities of wheat flour slurry, dough properties, and the finished product. After 24 and 96 h of storage, investigations were conducted on the finished product. Micro-doughLab was used to assess dough mixing qualities, and a texture profile analysis (TPA) test was used to assess the texture. A hedonic sensory test of texture, scent, taste, color, and general approval was also conducted. The type of gum used had a significant impact on the physical properties of the bread and cake and their evolution through time. Reduced amylose retrogradation was demonstrated by the lower peak viscosity and substantially lower setback of wheat flour gels, which corresponded to lower gel hardness. Gums were superior at increasing the bread loaf volume, especially GZ, although gums had the opposite effect on cake volume. After both storage periods, the hardness of the bread and cake was much lower than that of the control. Except when 2% GC was used, adding GC and GZ gums to bread and cake invariably increased the overall acceptability of the product. In terms of shelf-life, GZ was able to retain all texture parameters, volume, and general acceptability close to the control after storage.

9.
Molecules ; 28(1)2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36615198

RESUMO

The effectiveness of hydrocolloids (2% maximum in various combinations) from various sources, including maltodextrins (MD) with polymerization degree (DP) 18 and ziziphus gum (ZG), on the dough properties and quality of panned bread, as well as the possibility of using them to delay the bread staling process, have been investigated after 24, 72, and 96 h of storage. By evaluating the pasting capabilities of wheat flour slurry, dough properties, and the final product, the effects of the ziziphus gum (ZG) and maltodextrins (MD) were ascertained. A TA-TXT texture analyzer, a texture profile analysis test, and Micro-doughLab were used to evaluate the dough mixing properties. Additionally, a hedonic sensory evaluation of the overall acceptance of the bread, as well as its texture, aroma, taste, and color, was done. It is clear that MD had a more distinct impact than ZG on the way dough was mixed, the texture of the gel, and the finished product. The combination of MD and ZG significantly altered the bread's physical characteristics and its aging over time. The decreased peak viscosity and noticeably smaller setback of wheat flour gels, which corresponded to lower gel hardness, serve as evidence of reduced amylose retrogradation. At 2%, MD outperformed ZG in terms of increasing water absorption, dough stability, and bread loaf volume. With the exception of the blend that included three times as much MD as ZG, all mixes, including the control, exhibited an increase in bread firmness as a function of time after storage. Overall, the panelists liked (score of 5 and above) the bread made with mixes that had either MD or ZG, or a combination of both.


Assuntos
Pão , Farinha , Pão/análise , Farinha/análise , Triticum , Polissacarídeos
10.
Saudi J Biol Sci ; 28(8): 4490-4499, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34354435

RESUMO

Food packaging serves purposes of food product safety and easy handling and transport by preventing chemical contamination and enhancing shelf life, which provides convenience for consumers. Various types of materials, including plastics, glass, metals, and papers and their composites, have been used for food packaging. However, owing to consumers' increased health awareness, the significance of transferring harmful materials from packaging materials into foods is of greater concern. This review highlights the interactions of food with packaging materials and elaborates the mechanism, types, and contributing factors of migration of chemical substances from the packaging to foods. Also, various types of chemical migrants from different packaging materials with their possible impacts on food safety and human health are discussed. We conclude with a future outlook based on legislative considerations and ongoing technical contributions to optimization of food-package interactions.

11.
Foods ; 10(6)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34063985

RESUMO

Octenyl-succinylated corn starch (Osan) was used to improve the physicochemical properties of ground beef patties. The study involved incorporation of 5 and 15% Osan and storage for 30 or 60 days at -20 °C. The tested parameters included cooking loss, microstructure image, firmness, color, and sensory evaluation of the prepared patties. Along with Osan, native corn starch was used as control and considered the patties with added animal fat. The data showed that Osan reduced the cooking loss and dimensional shrinkage significantly (p < 0.05), whereas the moisture retention, firmness and color of beef patties were improved. The sensory evaluation indicated enhanced tenderness and juiciness without significant alteration of flavor, color, and overall acceptability of the cooked patties. Microstructure images of cooked patties indicated uniform/cohesive structures with small pore size of patties shaped with Osan. Obviously, good storability of the uncooked patties was reflected on the physiochemical, textural, color, and sensory evaluation of the cooked patties, which points to the benefit of using Osan in frozen patties and signifies possible use in the meat industry. The overall sensory acceptability scores were given to cooked patties containing Osan starch as well as the native starch, whereas 15% animal fat was favored too.

12.
Food Sci Nutr ; 9(6): 3336-3345, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34136198

RESUMO

The core objective of current research was determined to nutritional and bioactive profile of maize bran (MB)-enriched flour in relation to its end-use product quality. Furthermore, rheological properties of MB-enriched flour at different levels (5%, 10%, and 15%) were explicated through farinograph and mixograph. Moreover, bread was prepared with the addition of MB-enriched flour and was characterized for nutritional and textural properties. Results showed that MB-enriched flour having high water absorption and water retaining potential up to 4%-7% as compared to wheat flour (WF). Moreover, dough height gradually decreased with the addition of MB due to water-binding ability of bran which causes a decrease in gas retention during fermentation. This resulted in bread volume decrease (4%-7%) as compared to WF. Furthermore, the moisture content and hardness increased with the addition of MB. The water activity of bread slightly increased with the addition of maize bran after 4-day storage. Conclusively, MB-enriched flour improved nutritional, textural, and sensorial properties of final product.

13.
Food Sci Nutr ; 9(1): 244-250, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33473288

RESUMO

The main objective of current study was to evaluate the antioxidant potential and nutritional composition of milk thistle with special reference to silymarin. For the purpose, different varieties of milk thistle were procured from three different cities of Pakistan. The study was comprised of three different phases. In 1st phase, nutritional composition, that is, moisture, fat, protein, fiber, and nitrogen free extract, was determined according to their respective methods. Moreover, antioxidant potential and quantification of silymarin content were explored in 2nd phase. Furthermore, in last phase, milk thistle seeds tea was developed and evaluated for nutritional and sensorial characteristics. At last, data obtained from each parameter was subjected to appropriate statistical design to determine the level of significance. Results showed significant difference in the nutritional and chemical composition of different milk thistle varieties as well as locations. Moreover, moisture content, ash content, fat content, fiber content, protein content, and NFE varied from 6.27% to 5.01%, 2.37 to 1.25%, 23.19 to 19.74%, 7.4 to 4.39%, 30.09 to 20.74%, and 45.42 to 34.13%, respectively. Furthermore, silymarin content quantified though HPLC ranged from 1669.5 mg/g to 1607.6 mg/g for soxhlet extract whereas, 1,840.6 mg/g to 1765.9 mg/g for microwave-assisted extraction extract. Conclusively, it was depicted from the results that in case of variety, Blue was the best than White whereas, Islamabad was best in case of location.

14.
Food Sci Nutr ; 8(10): 5392-5401, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33133541

RESUMO

The objective of the current study was to explore the probiotics carrier potential of apple dried snacks and improve the survival of probiotics under simulated gastrointestinal conditions. Purposely, the probiotics were encapsulated using two hydrogel materials (sodium alginate and carrageenan) by using encapsulator. Briefly, slices of apple were immersed in solution containing free and encapsulated probiotics and then dried by conventional drying method. The dried apple snack was analyzed for different characteristics (physiochemical and microbiological) during storage. The viability of the free and encapsulated probiotics was accessed in apple snack and under simulated gastrointestinal conditions. Apple snack rich with encapsulated probiotics showed a significant result (p < .05) regarding the survival and stability. The encapsulated probiotics decreased from 9.5 log CFU/g to 8.83 log CFU/g as compared to free probiotics that decreased to 5.28 log CFU/g. Furthermore, encapsulated probiotics exhibited a better stability under simulated gastrointestinal conditions as compared to free. During storage, an increase in phenolic content and hardness was observed while decrease in pH was noted. Results of sensory parameters indicated apple snack as potential and acceptable probiotics carrier.

15.
Foods ; 9(7)2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32664209

RESUMO

Incorporation of hydrocolloid gums in native starches help to improve their pasting, thermal, rheological and textural properties along with improvement in the stability of starch gels. The use of Cordia gum is not widely studied as a starch modifier and this fact could make this study more interesting and unique. This study investigated the effects of the non-conventional hydrocolloid gum (Cordia gum) on corn starch properties. Corn starch and gum Cordia (GC) blends were prepared at different replacement levels (0%, 3%, 6%, 9%, and 12%). The effect of GC levels on pasting, thermal, rheological, and textural properties were evaluated using rapid viscoanalyzer, differential scanning colorimeter, rheometer, and texture analyzer. The presence of GC significantly increased starch gelatinization temperatures, enthalpies, peak viscosities, final viscosities, and setback viscosities. GC improved freeze thaw stability in starch. The shear rate (1/s) versus shear stress (σ) data of all samples fitted well to the simple power law model (R2 = 0.97-0.99). The control had the lowest flow behavior index (n; 0.17), which increased to (0.36-0.56) with increasing GC levels. The consistency index (K) of the starch-gum blends increased with increasing GC levels. The dominance of elastic properties over viscous properties was demonstrated by G' > G″. The magnitudes of G' and G″ increased with increasing GC concentration. The outcomes could help to use this modification method as an alternative to chemical and enzymatic modification with respect to cost, safety, less time consumption and less requirement of process modifications.

16.
Foods ; 9(1)2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31936051

RESUMO

This study was conducted to investigate the effect of various native starches on the rheological and textural properties of non-fat set yogurt. The yogurt samples were prepared while using five types of starches (potato, sweet potato, corn, chickpea, and Turkish beans). The physical properties of the prepared yogurt were analyzed while using shear viscosity, viscoelasticity, and texture analysis. The tests were performed after 0, 7, and 15 days storage. The effect of these starches on the yogurt viscoelastic properties, texture, syneresis, and sensory evaluation were determined under optimum conditions. The results showed that adding 1% starch could significantly (p < 0.05) reduce syneresis and improve yogurt firmness. Starches exhibited different effect on the overall quality of the yogurt due to their origin and amylose content. Regardless of the number of storage period duration, all of the samples, including the control behaved as pseudoplastic materials (n < 1) with various levels of pseudoplasticity. Yogurts with corn and tuber starches had the highest consistency coefficient (k), which indicated higher viscosity. The yogurt sample with chickpea starch exhibited the highest G´, making the gel more solid like. Therefore, the influence of tuber starches (potato and sweet potato) on G´ was different when compared to corn or legume starches. The behavior of the starches changed with storage time, where some starches performed better only at the beginning of the storage period duration. Wheying-off was significantly reduced, regardless of starch type. The pH of the yogurt remained unchanged through storage. Sensory evaluation showed a preference for starch-containing samples as compared to the control, regardless of the starch type. The variation in yogurt quality as a function of starch type could be attributed to the starch granule structure, gelatinization mechanism, or amylose content.

17.
Foods ; 8(12)2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31888161

RESUMO

The study was planned to evaluate the effect of non-commercial gums as compared to commercial gums. The concentration dependent effect of two commercial (arabic, xanthan) and four non-commercial (cress seed, fenugreek, flaxseed, okra) polysaccharide gums on the pasting, rheological, textural and thermal properties of chickpea were investigated by rapid visco analyzer (RVA), hybrid rheometer, texture analyzer and differential scanning calorimetry (DSC). Blends were prepared by replacing chickpea starch at 0.5% and 2.0% with gums, whereas native chickpea starch was used as a control. RVA data showed that peak and final viscosities were dramatically increased with xanthan contrary to reduction with gum arabic, flaxseed and okra gums. Hybrid rheometer displayed that storage and loss moduli were increased as a function of angular frequency and dominance of elastic properties over viscous ones. Xanthan blend was less temperature dependent due to dramatic decrease in activation energy value as compared to control while other gums were more temperature dependent. The magnitude of this effect was reliant on the type and concentration of gum. After storage for 21 days at -20 °C, total syneresis was reduced with the incorporation of xanthan and cress seed and also with high levels of gum arabic, flaxseed and fenugreek gums. The gel hardness was increased after overnight storage at ambient temperature (23 °C) with fenugreek while reduction in hardness was observed with xanthan, flaxseed and okra gums. The presence of gums resulted in significantly higher onset and peak temperatures determined through differential scanning calorimetry.

18.
Talanta ; 174: 587-598, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28738626

RESUMO

Infrared analysis of proteins and polysaccharides by the well known KBr disk technique is notoriously frustrated and defeated by absorbed water interference in the important amide and hydroxyl regions of spectra. This interference has too often been overlooked or ignored even when the resulting distortion is critical or even fatal, as in quantitative analyses of protein secondary structure, because the water has been impossible to measure or eliminate. Therefore, a new chemometric method was devised that corrects spectra of materials in KBr disks by mathematically eliminating the water interference. A new concept termed the Beer-Lambert law absorbance ratio (R-matrix) model was augmented with water concentration ratios computed via an exponential decay kinetic model of the water absorption process in KBr, which rendered the otherwise indeterminate system of linear equations determinate and thus possible to solve in a formal analytic manner. Consequently, the heretofore baffling KBr water elimination problem is now solved once and for all. Using the new formal solution, efforts to eliminate water interference from KBr disks in research will be defeated no longer. Resulting spectra of protein were much more accurate than attenuated total reflection (ATR) spectra corrected using the well-accepted Advanced ATR Correction Algorithm.

19.
Carbohydr Polym ; 89(1): 199-207, 2012 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-24750624

RESUMO

The effect of okra gum (OE) on the physical properties of rice and sorghum starches was investigated using rapid visco-analyzer (RVA), Brookfield viscometer, differential scanning Calorimetry (DSC), and light microscopy. Starch was replaced with 5, 10, 15% OE weight basis (g/100 g). In the presence of OE, the peak and final viscosity as well as the setback of both starches were reduced. However, the difference between the theoretical and the measured setback was more than just can be attributed to the omitted starch. The DSC data of the blends showed higher peak temperature compared to the control, indicating slower starch gelatinization in the presence of OE. Brookfield profiles demonstrated increase in shear stress at higher shear rate confirming pseudoplasticity of the system (n<1). Over all, it can be assumed that OE has influenced the properties of the starches, particularly, by decreasing viscosity, setback, and pseudoplasticity of the starch gels.


Assuntos
Abelmoschus , Oryza , Gomas Vegetais/química , Sorghum , Amido/química , Temperatura Alta , Reologia , Viscosidade
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