100 mL; 200,000 Units. 2,000 U/mL
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|Content:||100 mL; 200,000 Units. 2,000 U/mL|
|Storage Temperature:||Below -10oC|
|Formulation:||In 50% (v/v) glycerol|
|Stability:||Minimum 1 year at < -10oC. Check vial for details.|
|Synonyms:||beta-fructofuranosidase; beta-D-fructofuranoside fructohydrolase|
|Concentration:||Supplied at ~ 2,000 U/mL|
|Expression:||Purified from Yeast|
|Specificity:||Hydrolysis of terminal non-reducing β-D-fructofuranoside residues in β-D-fructofuranosides.|
|Specific Activity:||~ 300 U/mg protein (40oC, pH 4.5 on sucrose)|
|Unit Definition:||One Unit of invertase activity is defined as the amount of enzyme required to hydrolyze one µmole of sucrose (1% w/v) per minute in sodium acetate buffer (100mM), pH 4.5 at 40oC.|
|Application examples:||Applications for the measurement of fructans in foods.|
Formulation of gluten-free biscuits with reduced glycaemic index: Focus on in vitro glucose release, physical and sensory properties.
Di Cairano, M., Condelli, N., Cela, N., Sportiello, L., Caruso, M. C. & Galgano, F. (2021). LWT, 154, 112654.
Gluten-free (GF) biscuits based on buckwheat, sorghum and lentil flours were produced in an industrial plant. These flours are very little exploited in commercial products. In addition, since there is growing attention on glycaemic index (GI) of cereal based products. Sucrose replacers, mainly maltitol and inulin, and type 2 resistant starch (RS) were used to substitute sucrose and flours, respectively, in the view of reducing GI of biscuits. Ingredients were used in amounts established on the basis of previous experiments and European Regulations on nutritional claims. This study aimed at the evaluation of the effect of maltitol, inulin and RS on physico-chemical and sensory characteristics of biscuits. In particular, glucose released by sucrose and starch hydrolysis during in vitro digestion was placed under the spotlight. The use of sucrose contributed to the reduction of in vitro glucose release and consequently of predicted glycaemic index (pGI) with values decreasing from 84 to 67. Despite some slight differences in the sensory profile of the biscuits, reformulated products had a reduced friability and sweetness, and increased adhesiveness and nuts odour, all the formulations scored well above the threshold of acceptability (from 6.5 to 7.6) by consumers used to eat biscuits made with alternate flours.Hide Abstract
Mishra, S., Edwards, H., Hedderley, D., Podd, J. & Monro, J. (2017). Nutrients, 9(11), 1195.
Kiwifruit (KF) effects on the human glycaemic response to co-ingested wheat cereal were determined. Participants (n = 20) consumed four meals in random order, all being made to 40 g of the same available carbohydrate, by adding kiwifruit sugars (KF sug; glucose, fructose, sucrose 2:2:1) to meals not containing KF. The meals were flaked wheat biscuit (WB)+KFsug, WB+KF, WB+guar gum+KFsug, WB+guar gum+KF, that was ingested after fasting overnight. Blood glucose was monitored 3 h and hunger measured at 180 min post-meal using a visual analogue scale. KF and guar reduced postprandial blood glucose response amplitude, and prevented subsequent hypoglycaemia that occurred with WB+KFsug. The area between the blood glucose response curve and baseline from 0 to 180 min was not significantly different between meals, 0–120 min areas were significantly reduced by KF and/or guar. Area from 120 to 180 min was positive for KF, guar, and KF+guar, while the area for the WB meal was negative. Hunger at 180 min was significantly reduced by KF and/or guar when compared with WB. We conclude that KF components other than available carbohydrate may improve the glycaemic response profile to co-ingested cereal food.Hide Abstract
Efficacy of reducing sugar and phenol–sulfuric acid assays for analysis of soluble carbohydrates in feedstuffs.
Hall, M. B. (2013). Animal Feed Science and Technology, 185(1), 94-100.
Reducing sugar (RSA) and phenol–sulfuric acid (PSA) assays are commonly used to analyze water-soluble carbohydrates. However, questions have arisen as to their accuracy for measurements of feedstuffs with diverse carbohydrate profiles. This study evaluated the efficacy of RSA and PSA as they would commonly be applied in feed analysis laboratories in measuring a variety of purified carbohydrates. Carbohydrates analyzed were glucose (Glc), fructose (Fru), galactose (Gal), sucrose (Suc), maltose (Mal), lactose (Lac), raffinose (Raf), and inulin (Inu). Variations on the methods used were PSA using Suc (PSA-Suc) or Glc (PSA-Glc) as standard sugars, and RSA with a 50:50 Glc:Fru blend as the standard with four hydrolysis methods: acid hydrolysis with 0.037 M sulfuric acid (RSA-H2SO4) or 0.5M hydrochloric acid (RSA-HCl), or enzymatic hydrolysis with invertase (RSA-Inv) or an enzyme blend including sucrase, α-glucosidase, and β-galactosidase (RSA-EnzBl). Recovery of carbohydrate was calculated on a dry matter (DM) basis as (carbohydrate detected g/kg DM)/(carbohydrate present kg/kg DM), with ‘close to’ complete recovery defined as values falling within the range of 920–1080 g/kg. Monosaccharide recovery did not differ between unhydrolyzed vs. hydrolyzed samples in RSA indicating no destruction of carbohydrate by hydrolysis method. For RSA, recoveries of Glc, Fru, and Gal were 979, 1042, and 706 g/kg, respectively. Such response differences among monosaccharides are inherent to RSA, and can affect carbohydrate recovery values. Methods that provided close to complete recovery by carbohydrate were: PSA-Suc and all RSA for Suc; PSA-Glc and RSA-EnzBl for Mal and Lac; PSA-Suc, RSA-H2SO4, RSA-HCl, and RSA-Inv for Raf; and RSA-H2SO4 and RS-HCl for Inu. None of the assays gave complete recovery of the diverse set of purified carbohydrates. Allowing a range of 920–1080 g/kg for recoveries on individual carbohydrates, RSA-H2SO4 and RSA-HCl would give the closest to complete recovery values for feeds such as forage and soybean in which Suc, Raf, and Inu were important, whereas RSA-EnzBl would be useful in feeds such as forages or dairy products when Suc, Mal, and Lac are of interest. The allowed 920–1080 g/kg range of acceptable recoveries addresses the point that given very diverse carbohydrate complements of feeds, these assays will not be extremely precise, but may still be serviceable for diet formulation. The most accurate measurements will be achieved by selection of detection method, hydrolysis method, and carbohydrate standard to give greatest recovery of predominant carbohydrates in feedstuffs.Hide Abstract
Method for the Direct Determination of Available Carbohydrates in Low-Carbohydrate Products Using High-Performance Anion Exchange Chromatography.
Ellingson, D., Potts, B., Anderson, P., Burkhardt, G., Ellefson, W., Sullivan, D., Jacobs, W. & Ragan, R. (2010). Journal of AOAC International, 93(6), 1897-1904.
An improved method for direct determination of available carbohydrates in low-level products has been developed and validated for a low-carbohydrate soy infant formula. The method involves modification of an existing direct determination method to improve specificity, accuracy, detection levels, and run times through a more extensive enzymatic digestion to capture all available (or potentially available) carbohydrates. The digestion hydrolyzes all common sugars, starch, and starch derivatives down to their monosaccharide components, glucose, fructose, and galactose, which are then quantitated by high-performance anion-exchange chromatography with photodiode array detection. Method validation consisted of specificity testing and 10 days of analyzing various spike levels of mixed sugars, maltodextrin, and corn starch. The overall RSD was 4.0 across all sample types, which contained within-day and day-to-day components of 3.6 and 3.4, respectively. Overall average recovery was 99.4 (n = 10). Average recovery for individual spiked samples ranged from 94.1 to 106 (n = 10). It is expected that the method could be applied to a variety of low-carbohydrate foods and beverages.Hide Abstract
Patton, A. J., Cunningham, S. M., Volenec, J. J. & Reicher, Z. J. (2007). Crop Science, 47(5), 2170-2181.
Cold hardiness among zoysiagrass (Zoysia spp.) genotypes varies, but the physiological basis for cold hardiness is not completely understood. The objective of this study was to determine the relationship of carbohydrate (starch, total soluble sugars, total reducing sugars, sucrose, glucose, and raffinose family oligosaccharides) and proline concentrations with the cold acclimation of zoysiagrass and the lethal temperature killing 50% of the plants (LT50). Thirteen genotypes of zoysiagrass were selected with contrasting levels of winter hardiness. Plants were grown for 4 wk of 8/2°C day/night cycles and a 10-h photoperiod of 300 µmol m-2 s-1 to induce cold acclimation. Rhizomes and stolons were sampled from nonacclimated and cold-acclimated plants and used for carbohydrate and proline analysis. Concentrations of soluble sugars and proline increased during cold acclimation, while starch concentrations decreased. Starch, sugar/starch ratio, glucose, total reducing sugars, and proline in cold-acclimated plants were correlated (r = 0.61, −0.67, −0.73, −0.62, and −0.62, respectively) with LT50. These correlations indicate that higher concentrations of total reducing sugars, glucose, and proline are positively associated with zoysiagrass freeze tolerance, whereas higher concentrations of starch appeared detrimental to freeze tolerance.Hide Abstract