Starch-iodine Color Research Articles

In Vitro Evaluation of Alpha-amylase Inhibition, Antioxidant Potential and Phytochemical Analysis of Acacia Modesta

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, which affects insulin secretion. Among several approaches to treat diabetes, controlling postprandial hyperglycemia is an effective way to manage diabetes type II. In this regard, medicinal plants are considered the best source of new chemical entities with fewer side effects. This study aims to evaluate the alpha-amylase inhibitory potential of Acacia modesta ethanol and aqueous extracts in correlation with its antioxidant potential and develop an anti-diabatic drug against the alpha-amylase enzyme that can control the post-prandial hyperglycemia. We used the starch-iodine color change method for α-amylase, a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay for determining the antioxidant potential and determined different phytochemicals, including phenols, flavonoids, and tannins by spectrophotometry. The results indicated that the gum of A. modesta possesses potent α-amylase inhibitory potential with IC 50 values of 100.4 ± 0.04 µg/mL in ethanol and 91.8 ± 0.05 µg/mL in the aqueous extract, which was approximately 3-folds higher compared to standard acarbose (286.8 ± 0.04 µM). The antioxidant activity was also higher in gum compared to any other part. As for phytochemical analysis, this plant possesses higher amounts of tannins and phenols, while flavonoids are in lesser amounts. The gum of A. modesta shows a dual mode of action, i.e., antioxidant and amylase inhibitor, which makes it a better candidate for diabetes management. The novelty is that, to our knowledge, this study is the first to report the anti-diabetic and antioxidant properties of A. modesta using pancreatic amylase as a drug target from Khyber Pakhtunkhwa, Pakistan. Keywords: Acacia modesta , alpha-amylase, flavonoids, tannins, antioxidant. https://doi.org/10.55463/issn.1674-2974.50.2.30

Optimization of acquisition parameters of slurry coating characteristics based on multiple yarn simultaneous detection

A simultaneous detection method was proposed to detect slurry coating characteristics based on the same spatial resolution of starch-based sized and raw yarns. A dynamic image acquisition device was improved to capture the apparent images of multiple yarns simultaneously after the starch–iodine color reaction. The slurry coating characteristics were calculated utilizing image-processing technology. For the sake of effective and stable detection, the effects of illumination conditions on the concentration of I2-KI solution were studied through the absorbance value test. The effects of image-processing parameters on the experimental results were analyzed respectively by measuring six kinds of yarn of different counts and size pick-up. The results showed that the illumination conditions within an illumination time of 0–60 min, illumination intensity of 0–80,000 lux and illumination distance of 0.01–0.20 m had no significant effects on the concentration of I2-KI solution. Eight rows of pixels in the central axis areas of the yarn were determined as the effective statistical areas. It was determined that the sample size can meet the needs of stability test in 200 pieces. A dynamic threshold method, which served the intersection of the gray histogram of sized and raw yarn under the same spatial resolution as the threshold, can effectively segment the slurry coating areas. On the above basis, the optimization acquisition parameters of the detection method were obtained. The proposed method can meet the requirements of the efficiency test, common applicability and ease of operation.

Structural characterization of an alkali-extracted polysaccharide from Dioscorea opposita Thunb. with initial studies on its anti-inflammatory activity

An alkali-extracted polysaccharide (HY-B) was isolated and purified from Dioscorea opposita Thunb. (Huai Yam). Its chemical structure was analyzed with FT-IR, GC-MS and 1 D, 2 D-NMR spectrometry. It was proved that HY-B is mainly composed of α-1,4-linked glucose, which is similar to starch, but the starch-iodine color test proved that it was not starch. The chain conformation of HY-B was analyzed by SEC-MALLS-RI and TEM, indicated that HY-B exists in a random coil conformation. Its molecular weight is 18.7 kDa, and the molecular size is about 100 nm. MTT assays indicated that HY-B was nontoxic to RAW 264.7 cells in vitro. The results of anti-inflammatory studies showed that HY-B could inhibit the production of NO and TNF-α in RAW 264.7 macrophage stimulated by lipopolysaccharides (LPSs). This work provided the important information about the anti-inflammatory active component of Huai Yam and its potential applications in the food and health industries.

A novel method for evaluating the slurry coating characteristics of sized yarns based on the starch-iodine color reaction principle and image processing

The slurry coating characteristics of sized yarns directly impact warp weavability. Due to the damage to sized films, the conventional methods of detecting sized-yarn coating characteristics have drawbacks of low efficiency and poor repeatability. A novel detecting method of slurry coating characteristics was proposed based on image processing. Through the starch-iodine color reaction principle, a self-made dynamic image acquisition device was developed in this paper, in which the apparent images of starch-based sized yarns after color reaction were captured consecutively. The slurry coating percentage ( SCP), slurry coating depth ( SCD) and slurry coating unevenness ( SCU), respectively reflecting the sizing coating integrity, sizing coating thickness and thickness unevenness, were extracted by image processing. The effects of experimental parameters, including immersion time and concentration of I2-KI solution, on slurry coating characteristics were analyzed, and central composite design was adopted to optimize the stability of the test system. Sized yarns commonly used in textile mills were characterized by the proposed method. The experimental results indicated that immersion time of 3.56 min and I2-KI concentration of 0.11‱ (‱ represents that the mass of the solute is one ten-thousandth of solution) led to the optimal stability of slurry coating characteristics (the CV of SCP, CV of SCD and CV of SCU were 3.32%, 5.56% and 9.37%, respectively). The much lower CV of the proposed method compared with conventional ones confirmed that the method was useful for evaluating slurry coating characteristics.

English

Pancreatic alpha (α)-amylase and intestinal α-glucosidase involved in the enzymatic breakdown of dietary carbohydrates are implicated in postprandial hyperglycemia. The inhibition of these two enzymes has been exploited in the design of antidiabetic drugs. This study was therefore designed to investigate the ability of the leaf extracts of Vitex doniana to inhibit α-amylase and α-glucosidase as well as the in-vivo antidiabetic potential of the ethanol leaf extract. The inhibitory potentials of the extracts on α-amylase were assayed through the method of starch-iodine colour change while α-glucosidase inhibition was assessed by measuring the release of 4-nitrophenol by p-nitrophenyl-α-D-glucopyranoside (pNPG). Acarbose was used as the standard. The extracts displayed a dose-dependent significant inhibition of the enzymes. The aqueous leaf extract of V. doniana was the strongest inhibitor of α-amylase with half-maximal inhibitory concentration (IC50) of 3.09 ± 0.22 mg/ml while the ethanol leaf extract was the strongest inhibitor of α-glucosidase with IC50 of 17.12 ±1.42 mg/ml. The result also showed that both extracts contain mixed inhibitors of the two enzymes. The result of the in-vivo antidiabetic study conducted for 14 days showed a significant (p<0.05) reduction in the fasting blood glucose level of the extract treated groups of animals compared to the untreated diabetic group.  These results strongly suggest that V. doniana can be exploited in the treatment of diabetes mellitus.   Key words: Vitex doniana, antidiabetic, inhibitory potential, Lineweaver-Burk, α-amylase, α-glucosidase. &nbsp

Exploration of Antidiabetic Activity of Stephania japonica Leaf Extract in Alloxan-Induced Swiss Albino Diabetic Mice

Aims: Presently the medicinal world is rapidly turning more on the therapeutic health benefits of natural product and medicinal plants in the management of major crucial disease and their complications. Medicinal plant, Stephania japonica has been studied for exploring antidiabetic potentiality as an alternative source of medicine against the global threat of Diabetes mellitus (DM).
 Methods: The extraction of S. japonica leaf was carried out by acetone and ethanol. Phytochemical screening and quantitative analysis of S. japonica leaf extracts were evaluated through chemically forming characterized color formation and calibration method respectively, by using standard reference substances (ascorbic acid, gallic acid, and quercetin) to assess the probable compounds present in the extract. Anti-diabetic potentiality of highest phytochemicals containing two extracts were investigated in in vitro as a ⍺-amylase inhibitors and in vivo through alloxan-induced Swiss albino diabetes mice model.
 Results: Alkaloids, carbohydrates, steroids, flavonoids, resins, saponins, tannins and coumarins were present in the leaf extracts. The estimated amount of total phenolics, flavonoids, flavonols and proanthrocyanidins contents of acetone and ethanol extract were 92.12±0.64 and 56.54±1.05 mg of gallic acid equivalent (GAE)/gm of dry extract, 66.02±1.42 and 46.17±0.54 mg of catechin equivalent (CAE)/gm of dry extract, 7.05±0.108 and 5.26±0.083 mg of quercetin equivalent (QUE)/gm of dry extract, 35.19±0.67 and 9.55±1.11 mg CAE/gm of dry extract, respectively. In 3, 5-dinitrosalicylic acid method, acetone and ethanol extract showed α-amylase inhibition of 51.02% and 46.62%, respectively at the concentration of 1000 µg/mL whereas in starch iodine color assay, acetone and ethanol extract showed inhibition of 57.32% and 52.12%, respectively at the concentration of 800 µg/mL. In contrast, both of the leaf extracts significantly (p<0.05 to p<0.001) improved the lipid profile parameters, blood glucose level and serum hepatic marker proteins in alloxan-induced diabetic mice.
 Conclusion: The present study strongly concluded that S. japonica leaf extracts process potent antidiabetic potentiality that might be significance for the management of diabetes and its complications.

A colorimetric assay for sensitive detection of hydrogen peroxide and glucose in microfluidic paper-based analytical devices integrated with starch-iodide-gelatin system

Microfluidic paper-based analytical devices (μPADs) for detection of hydrogen peroxide and glucose have been developed. The analytical performance of colorimetric detection using the conventional starch-iodine color reaction has been significantly improved by using gelatin as the surface modifier which retains the enzyme activity in the dry filter paper strip, improves antioxidability, as well as decreases the strong background signal. Under optimal conditions, the color intensities show a good linear relationship with glucose concentration ranging from 0.5 to 5 mM and hydrogen peroxide concentration from 0.5 to 6 mM, with the detection limit of 0.05 mM and 0.1 mM, respectively. In addition, the accuracy of colorimetric sensor has been successfully assessed in detecting glucose from real human serum samples and recovery value ranges from 95.7% to 97%, which are approaching to the glucose oxidase endpoint. The new colorimetric assay exhibits high sensitivity, good selectivity, acceptable stability and reproducibility. The present approach is promising for monitoring glucose for point of care diagnostic applications, especially in regions with resource-limited settings.

Pharmacognostic Evaluation and Pharmacological Validation of Sphaeranthus indicus DC

Sphaeranthus indicus is an important medicinal plant in Ayurveda which grows as weed in rice fields throughout India, Sri Lanka, Australia and Africa. The present study aimed for the pharmacognostical evaluation and pharmacological validation of this high-value medicinal species. All the pharmacognostical parameters were done as per the API guideline. A simple, rapid, sensitive and reproducible method was also developed for simultaneous HPTLC quantification of two bioactive compounds eugenol and β-sitosterol in S. indicus. The HPTLC was performed on silica gel 60 F254 by using toluene/ethyl acetate/glacial acetic acid (8:2:0.2) as a mobile phase for eugenol and β-sitosterol at Rf value 0.64 and 0.48, respectively. The content of eugenol (0.03%) and β-sitosterol (0.013%) was detected in dry weight per gram. In vitro activities viz. antioxidant, antidiabetic and anti-inflammatory were done to evaluate the pharmacological potential of S. indicus. Four antioxidant models viz. DPPH, ferric reducing power, 2-deoxyribose assay and antioxidant capacity were used to determine the free radical scanning. Antidiabetic and anti-inflammatory potential were determined by using starch–iodine colour assay and inhibition of protein denaturation model. IC50 value of S. indicus extract in DPPH and 2-deoxyribose assay was found (328.96 ± 0.003 µg/ml) and (30.36 ± 0.004 µg/ml), respectively. The present study will be helpful for quality check of the raw material and monitoring batch-to-batch consistency of herbal drugs, wherein S. indicus is used as an ingredient.

PHARMACOGNOSTICAL AND PHARMACOLOGICAL EVALUATION OF CRINUM LATIFOLIUM L.

Objective: Pharmacognostical study along with the development of a quantitative HPTLC method for Crinum latifolium and evaluation of its traditional claims.Methods: Quantification of three marker compounds oleanolic acid, linoleic acid, and lupeol was done through HPTLC. In vitro antioxidant activity was determined by six different models, namely total phenolic and total flavonoid content, DPPH radical scavenging assay, ferric reducing power, antioxidant capacity and hydroxyl radical scavenging assay. In vitro antidiabetic activity was evaluated by α-amylase inhibition assay based on starch iodine and DNS method.Results: The content of oleanolic acid, linoleic acid, and lupeol were found to be higher in aerial parts like 0.015%, 0.048%, and 0.028% respectively, while in root extract 0.006%, 0.027% and 0.025% respectively on a dry weight basis. Free radical scavenging activity was done by DPPH assay, showing the IC50 value of 410±1.105 µg/ml in roots and 441.95±1.788 in aerial parts. In vitro antidiabetic potential of both the parts were assessed by starch iodine color assay and DNS method of alpha-amylase inhibition model. In 3,5 DNS assay, IC50 of extract from aerial parts was 282.21±2.151µg/ml whereas in root extract it was 193.33±2.45µg/ml. Iodine-starch assay of C. latifolium (aerial part) shown the IC50 value of 340.81±0.49 µg/ml and C. latifolium (root) of 74.64±1.28 µg/ml.Conclusion: The results indicate that the aerial parts of the plant possess more antidiabetic potential in comparison to the root. Thus, the aerial part can be used to get better results as a drug and roots can be used as an alternative.

IN VITRO ANTI-DIABETIC ACTIVITY OF MICROENCAPSULATED AND NON-ENCAPSULATED ASTAXANTHIN

Objective: Diabetes is a long term condition which indicates the high blood pressure. The symptoms indicates, polyuria (frequent urination), they will become increasingly thirsty (polydipsia) and hungry (polyphagia). Many drugs has been discovered for curing diabetes. Recent studies reported that the administration of astaxanthin reduces the blood pressure in the diabetic patient. Astaxanthin is a powerful antioxidant found in wide variety of aquatic living organism which has wide applications in pharmacological studies.Methods: In vitro antidiabetic study of both encapsulated and non-encapsulated astaxanthin such as DNSA method, starch-iodine color assay method and α glycosidase enzymes assay was carried out.Results: The results of the present study indicated that both encapsulated and non-encapsulated astaxanthin shows higher antidiabetic activity in all the method. Each test samples possess the best activity when compared to standard drug acarbose.Conclusion: The present study, it is concluded that both non-encapsulated and encapsulated astaxanthin exhibit good antidiabetic activity.

English

Starch retrogradation is mainly due to the amylose fraction of starch. Amylose quantification is usually done by iodine staining with which it forms a blue colour complex while starch retrogradability can be monitored by freeze-thaw stability measurements. In this work, spectroscopic determination of the blue value and visual monitoring of starch–iodine colour complex were used to study starch retrogradation. The results obtained were compared with that from freeze-thaw stability measurements. Native cassava starch, its carboxymethylated and cyanoethylated derivatives of different degrees of substitution (D.S) were used in the study. From the results, increase in starch derivatization reduced amylose ability to bind iodine, decreased the blue value with resultant decay in the blue colour of the starch-iodine complex. The blue black colour of the starch-iodine complex was lost in carboxymethyl starch at D.S of 0.145 and cyanoethyl starch at D.S of 0.141; at these degrees of substitution, the helical structure of amylose was no longer maintained by the starch molecules and retrogradation eliminated. Freeze-thaw stability study showed clear pastes with no evidence of retrogradation over 10 freeze-thaw cycles for derivatized starches above these degrees of substitutions. This showed a good agreement with that obtained from the colour of the starch-iodine complex. Hence derivatized starch products, which showed absence of blue black colour of starch-iodine complex would be freeze-thaw stable over a long period of cold storage. The disappearance of the blue colour of starch-iodine complex thus becomes an index of retrogradability and freeze-thaw stability of starch pastes on cold storage. Key words: Starch pastes, retrogradability, blue value, starch-iodine colour.

Complexation of starch with dodecylamine

The chemical nature of the interaction of starch and dodecylamine (DDA), which generally act as depressant and collector, respectively, in the reverse flotation of bauxite, was investigated using starch-iodine tests. The results obtained from the blue-value measurements for starch+DDA+iodine system indicate the formation of the inclusion complex for amylose-DDA system at low DDA concentration (<2 mmol/L). However, it is less likely for amylopectin-DDA system with short helix. UV-Vis spectra of starch-iodine complexes show that each helix of amylose can accommodate two DDA molecules locating separately at its two ends, and in the helical cavity there is room available for the upcoming iodine. When concentrated DDA is tested, amylose-DDA system exhibits no characteristic starch-iodine color, owing to the presence of a compact coating of DDA molecules on starch via hydroxyl/amine hydrogen bonding. 1H NMR spectroscopy and surface tension determination help to clarify the interaction mechanism of amylose with DDA.

Traditional Medicinal Herbs and Food Plants Have the Potential to Inhibit Key Carbohydrate Hydrolyzing EnzymesIn Vitroand Reduce Postprandial Blood Glucose PeaksIn Vivo

We hypothesized that some medicinal herbs and food plants commonly used in the management of diabetes can reduce glucose peaks by inhibiting key carbohydrate hydrolyzing enzymes. To this effect, extracts of Antidesma madagascariense (AM), Erythroxylum macrocarpum (EM), Pittosporum senacia (PS), and Faujasiopsis flexuosa (FF), Momordica charantia (MC), and Ocimum tenuiflorum (OT) were evaluated for α-amylase and α-glucosidase inhibitory effects based on starch-iodine colour changes and PNP-G as substrate, respectively. Only FF and AM extracts/fractions were found to inhibit α-amylase activity significantly (P < 0.05) and coparable to the drug acarbose. Amylase bioassay on isolated mouse plasma confirmed the inhibitory potential of AM and FF extracts with the ethyl acetate fraction of FF being more potent (P < 0.05) than acarbose. Extracts/fractions of AM and MC were found to inhibit significantly (P < 0.05) α-glucosidase activity, with IC50 comparable to the drug 1-deoxynojirimycin. In vivo studies on glycogen-loaded mice showed significant (P < 0.05) depressive effect on elevation of postprandial blood glucose following ingestion of AM and MC extracts. Our findings tend to provide a possible explanation for the hypoglycemic action of MC fruits and AM leaf extracts as alternative nutritional therapy in the management of diabetes.

Potent α-amylase inhibitory activity of Indian Ayurvedic medicinal plants.

BackgroundIndian medicinal plants used in the Ayurvedic traditional system to treat diabetes are a valuable source of novel anti-diabetic agents. Pancreatic α-amylase inhibitors offer an effective strategy to lower the levels of post-prandial hyperglycemia via control of starch breakdown. In this study, seventeen Indian medicinal plants with known hypoglycemic properties were subjected to sequential solvent extraction and tested for α-amylase inhibition, in order to assess and evaluate their inhibitory potential on PPA (porcine pancreatic α-amylase). Preliminary phytochemical analysis of the lead extracts was performed in order to determine the probable constituents.MethodsAnalysis of the 126 extracts, obtained from 17 plants (Aloe vera (L.) Burm.f., Adansonia digitata L., Allium sativum L., Casia fistula L., Catharanthus roseus (L.) G. Don., Cinnamomum verum Persl., Coccinia grandis (L.) Voigt., Linum usitatisumum L., Mangifera indica L., Morus alba L., Nerium oleander L., Ocimum tenuiflorum L., Piper nigrum L., Terminalia chebula Retz., Tinospora cordifolia (Willd.) Miers., Trigonella foenum-graceum L., Zingiber officinale Rosc.) for PPA inhibition was initially performed qualitatively by starch-iodine colour assay. The lead extracts were further quantified with respect to PPA inhibition using the chromogenic DNSA (3, 5-dinitrosalicylic acid) method. Phytochemical constituents of the extracts exhibiting≥ 50% inhibition were analysed qualitatively as well as by GC-MS (Gas chromatography-Mass spectrometry).ResultsOf the 126 extracts obtained from 17 plants, 17 extracts exhibited PPA inhibitory potential to varying degrees (10%-60.5%) while 4 extracts showed low inhibition (< 10%). However, strong porcine pancreatic amylase inhibitory activity (> 50%) was obtained with 3 isopropanol extracts. All these 3 extracts exhibited concentration dependent inhibition with IC50 values, viz., seeds of Linum usitatisumum (540 μgml-1), leaves of Morus alba (1440 μgml-1) and Ocimum tenuiflorum (8.9 μgml-1). Acarbose as the standard inhibitor exhibited an IC50 (half maximal inhibitory concentration)value of 10.2 μgml-1. Phytochemical analysis revealed the presence of alkaloids, tannins, cardiac glycosides, flavonoids, saponins and steroids with the major phytoconstituents being identified by GC-MS.ConclusionsThis study endorses the use of these plants for further studies to determine their potential for type 2 diabetes management. Results suggests that extracts of Linum usitatisumum, Morus alba and Ocimum tenuiflorum act effectively as PPA inhibitors leading to a reduction in starch hydrolysis and hence eventually to lowered glucose levels.

Interference of thiol-compounds with dextrinizing activity assay of α-amylase by starch-iodine colour reaction: Modification of the method to eliminate this interference

Interference of Luria broth and other bacteriological media with the starch–iodine colour assay of the dextrinizing activity of α-amylase (Fuwa's method) was observed, complete bleaching occurring with 0.4ml of the Luria broth. The interference was found to be due to the thiol groups present in the medium which compete with starch for iodine. Among the various metal salts tested for counteracting the interference, ZnSO4 was found to be the best which reverted the colour to about 73–85% of that of the blank. A combination of hydrogen peroxide (10 μl of 30% solution) and CuSO4 · 5H2O (50 μl of 0.1 M solution) completely protected the starch–iodine reaction in the presence of even 0.5 ml of Luria broth and a modified assay was developed based on this finding. The colour intensity, however, was almost double than that obtained for the same amount of starch and iodine in the absence of these protective agents. Nevertheless, with different concentrations of starch as well as with varying amounts of enzymes, the modified method showed perfect linearity and could be effectively used for estimation of dextrinizing activity of α-amylase in the presence of thiol groups.

A continuous monitoring technique for the determination of alpha-amylase from disaggregated hamster parotid gland cells using an amyloclastic method

In order to determine the amount of amylase/cell in hamster parotid epithelial cells following their purification in a previously described isokinetic gradient (1), we required a very sensitive assay which could be used to examine samples obtained from very small numbers of cells. The kinetic method reported herein requires only 50 μl of enzyme solution. The initial velocity of the reaction can be determined in 3 min by monitoring the decrease in the starch-iodine color at 610 nm in a solution containing starch, iodine, and potassium iodide. Using this method, the amylase activity of a sonicated suspension of unpurified hamster parotid cells was 0.23 mg starch degraded/min/million epithelial cells. This method eliminates the problem of decolorization of the starch-iodine complex by proteins such as albumin since relatively small amounts of enzyme solution are required, the method measures the relative decrease in absorbance with time, and excess iodine is present to combine with the protein. The method offers the additional advantage that it is not necessary to remove samples of the reacting mixture, and the problems of stopping the reaction and contamination of the reaction mixture are eliminated. The method is compared with the methods of Somogyi (3) and Jacobsen and Hensten-Pettersen (13).

Acid-stable α-Amylase of Black Aspergilli

Some general properties of the acid-stable dextrinizing amylase of black Aspergillus were investigated comparing with those of Taka-amylase A. The mode of action on starch of this amylase was quite similar to that of Taka-amylase A. Saccharifying degree at red point in starch-iodine color reaction was 5.1% and the limit of starch saccharification was a little over 40 per cent calculated as glucose with both amylases. Maltase activity was absent. Degradation products in the course of starch hydrolysis were also quite similar and they mutarotated downward. So this amylase was decided to be α-type. Thermal stability of the acid-stable α-amylase was higher than that of Taka-amylase A. Its acid stability was much higher than that of Taka-amylase A. Taka-amylase A was inactivated completely at pH 2.2, 37°C, for 30 min, but the acid-stable α-amylase retained 87% of its original activity.From the amylase preparation of black Aspergillus acid-stable α-amylase and acidunstable α-amylase were separated by gel filtra...

Salivary amylase. I. An assay method of alpha-amylase.

A micromodification of Somogyi’s starch-iodine colour method for determination of α-amylase in media from salivary gland tissue cultures, as well as homogenates of such tissues and in saliva, is described. The method was based on photometric determination of the starch-iodine colour changes during enzymic degradation of starch substrate at wavelengths 550 or 610 nm. No additional, apparently amylolytic effect, such as seen in serum, was observed by addition to the samples of 1 mg/ml of albumin and globulin, or about 1 mg/ml of proteins from homogenate of spleen. The test allows a reproducible and rapid way of calculating arbitrary units of α-amylase.

Some Physico-Chemical Properties of Non-Waxy Paddy Rice Starch in Niigata Prefecture

Fifteen samples of milled rice had protein contents ranging from 5.53 to 7.83% and amylose contents ranging from 17.6 to 22.1%. Eating and cooking qualities of cooked rice gave gross palatability indicies ranging from 100 to 61, cohesiveness values by balance method from 64 to 9, and starch-iodine color test values of milled rice from 0.297 to 0.574. Pasting characteristics of a 8% suspension of rice starch gave maximum viscosity values ranging from 550 to 380 Brabender Unit (B.U.), temperature at maximum viscosity from 82° to 92.5°C, break down values from 260 to 20B.U., and set back values from −0.5 to 60B.U. Good correlations were found between cooking and eating qualities of rice and rheological property of starch, and between rheological property and amylose content of starch, respectively.

SIMPLIFIED METHOD FOR CALCULATING THE RESULTS OBTAINED WITH BRIGGS' α-AMYLASE ASSAY

A theoretical basis for Briggs' starch iodine colour α-amylase assay is presented and, from this, a simple method for calculation of α-amylase concentration is derived.