Extraction of hull-less barley (cultivar Lut) ß-glycan using hot water: Optimization using response surface methodology

Document Type : Research Article

Authors

• Arash Koocheki ¹
• Abdollah Hematian Sourki ¹
• Mohammad Elahi ²
• Seyed Mohammad Ali Razavi ¹

¹ Ferdowsi University of Mashhad

² Food Science and Technology Engineering

https://doi.org/10.22067/ifstrj.v12i5.41416

Abstract

Introduction: β-glucan is the most important water soluble fiber found in cell wall of some cereals such as barley, oat, wheat and rye, that are composed of β-D-glucoseunits with (1→4) (70%) and (1→3) (30%)anomericbonds(Benito-Román, Alonso, & Cocero, 2013).β-glucan is regarded as a dietary fiber in functional foods. It can act as a hydrocolloid due to its thickening characteristic in aqueous phase and can be used as a stabilizer in some foods such as sauces, salad dressing and ice cream (Dawkins & Nnanna, 1995; Kontogiorgos, Biliaderis, Kiosseoglou, & Doxastakis, 2004; Temelli, 1997; Wood & Webster, 1986). Hull-less barley is a barley variety that has no hard coat around its’ seeds. The content of soluble fiber e.g. β-glucan in hull-less barley is higher than of ordinary barley varieties. Hull-lessbarley cv. Lut is the first commercial hull-less barley in Iran registered in 2013 by SPII(Seed and Plant Improvement Institute). Lut is a kind of spring barley cultivar which is precocious and resistant to lodging. It’s average yield is 6.425 t/ha and it is suitable to cultivation in temperate regions of Iran (SPII, 2013).This type of barley contains about 6% β-glucan and thus is a good source for β-glucan extraction.To date no research has been conducted on properties of β-glucan from this cultivar of barley.Considering high technological properties of β-glucan, the present study was carried out to determine the optimal condition for extraction of β-glucan from hull-lessbarley using hot watermethod to achieve the highest qualitative and best functional properties.

Materials and methods: Barley flour was obtained by grinding whole kernels of cv. Lut in a laboratory mill and sieved through a 0.50 mm screen. Prior to the extraction procedure, 50 g of barley flour was suspended in 200 ml of aqueous ethanol (80%, v/v) and stirred under reflux for 3 h to remove most of the lipids and inactivate the endogenous β-glucanases. The liquid phase was separated by vacuum filtration and dried at 40 °C for 12 h. 50 g of dried defatted barley flour was suspended in specified amounts of distilled water (solven:flour ratio = 6:1, 8:1 and 10:1) in a 1000 ml beaker. pH was adjusted to the designed levels (5, 7, and 9) by 0.1 N HCl and 0.1 N NaOH solutions. Extraction procedure carried out at 50±1°C for 30, 60 and 90 minutes. Total β-glucan content was determined by the specific enzymatic method of McClear and Glennie-Holmes (1985) using the mixed linkage β-glucan assay kit (K-BGLU 07/11) supplied by Megazyme International (Wicklow, Ireland). The colour of β-glucan gums was measuredusing a Hunter-Lab Colour Flex 45 spectrophotometer (Hunter Associates Laboratory, Inc., Reston, VA, USA). The L*a*b* (CIELAB space) colour space measurement was used for colour analysis of β-glucan samples. Emulsion stability (ES) against high temperature was determined by heating emulsions in a water bath at 80 °C for 30 min followed by centrifuging at 1200 g for 10 min. For foam stability, ovalbumin was dissolved in distilled water and added to β-glucan solution and then whipped vigorously with a laboratory rotor-stator homogenizer at room temperature. Flow behaviour measurements were done by a Brookfield viscometer. The flow behavior index (n) and consistency coefficient (k) values were obtained by fitting the power law model. All chemicals, reagents and solvents were of analytical grade and obtained either from Sigma-Aldrich Co (Deisenhofen, Germany) or from Merck (Darmstadt, Germany).

Results &Discussion: Results showed that the extraction time, solvent: flour ratio and pH had significant effect on extraction yield, purity, foam and emulsion stability, consistency coefficient (k), flow behavior index (n) and colour. Increasing the extraction time had significant effects on β-glucan’s yield and purity and improved the emulsion and foam stabilizing effect of β-glucan. Increasing the pH from 5 to 9 significantly enhanced the purity, consistency coefficient (k), foam and emulsion stability. At higher pH levels, extraction yield, flow behavior index (n) and L* decreased. With increasing solvent:flour ratio, extraction yield, purity, consistency coefficient (k), foam and emulsion stability significantly increased. In contrast, the flow behavior index (n) decreased as a result of increase in solvent: flour ratio. However, solvent: flour ratio had no significant effect on L*, a* and b*. Models presented in this study were highly significant and the correlation coefficients could be used for optimization of ß-glucan extraction from hull-less barley. Considering the importance and desirability of the response variables, the best results were obtained when the extraction time, solvent: flour ratio and pH were 90 min, 10:1 and 7.33 respectively. At the optimal condition, extraction yield, purity, foam stability, emulsion stability, consistency coefficient (k), flow behavior index (n), L*, a* and b* were 4.12%, 69.11%, 86.95%, 88.77%, 1.51 Pa.sn, 0.62, 73.42, 0.81 and 8.72 respectively.

Keywords

• : ß-glucan
• Hulless Barley
• water extraction
• Response surface method
• Flow behavior
• foam and emulsion stability

References

افشاری جویباری، ح.، فرحناکی، ع. 1388. امکان استفاده از نرم افزار فتوشاپ برای اندازه گیری رنگ مواد غذائی: بررسی تغییرات رنگ خرمای مضافتی بم در طی رساندن مصنوعی. پژوهش‌های صنایع غذایی ایران، 5(1)، 37-46.

امیری عقدایی، س. س.، اعلمی، م.، جعفری، س. م. و صادقی ماهونک، ع. 1389. ویژگی‌های فیزیکوشیمیایی و رئولوژیک بتاگلوکان استخراج شده از جو بدون پوشینه. پژوهش‌های علوم و صنایع غذایی ایران، 6(4)، 286-296.

جهانیان، ل.، حمیدی اصفهانی، ز.، مرتضوی، ع. 1383. بررسی اثر زانتان و کاراجینان بر خصوصیات کف ایزوله پروتئینی سویا. فصلنامه علوم و صنایع غذایی ایران، 1(1)، 39-48.

شکرالهی، ب. 1392. ارزیابی تاثیر فراصوت بر ویژگی‌های عملکردی ایزوله پروتئینی عدس. پایان نامه کارشناسی ارشد، دانشگاه فردوسی مشهد، مشهد، ایران.

Ahmad, A., Anjum, F. M., Zahoor, T., Nawaz, H., Ahmed, Z., 2010, Extraction and characterization of β-d-glucan from oat for industrial utilization. International Journal of Biological Macromolecules, 46(3), 304-309.

Ahmad, A., Anjum, F.M., Zahoor, T., Nawaz, H., Din, A., 2009, Physicochemical and functional properties of barley β-glucan as affected by different extraction procedures. International Journal of Food Science & Technology, 44(1), 181-187.

Bhatty, R.S, 1995, Laboratory and Pilot Plant Extraction and Purification of -Glucans from Hull-less Barley and Oat Brans. Journal of Cereal Science 22, 163-170.

Beer, M. U., Wood, P. J., Weisz, J., 1997, Molecular Weight Distribution and (1→ 3)(1→ 4)-β-d-Glucan Content of Consecutive Extracts of Various Oat and Barley Cultivars 1. Cereal chemistry, 74(4), 476-480.

Brennan, C. S., Cleary, L. J., 2005, The potential use of cereal (1→3,1→4)-β-d-glucans as functional food ingredients. Journal of Cereal Science, 42(1), 1-13.

Burkus, Z., Temelli, F., 1998, Effect of extraction conditions on yield, composition, and viscosity stability ofbarley β-glucan gum. Cereal chemistry, 75(6), 805-809.

Burkus, Z., Temelli, F., 2005, Rheological properties of barley β-glucan. Carbohydrate Polymers, 59(4), 459-465.

Carr, J.M., Glatter, S., Jeraci, J.L., Lewis, B.A., 1990, Enzymic determination of b-glucan in cereal-basedfood products. Cereal Chemistry, 67, 226-229.

Dawkins, N. L., Nnanna, I. A., 1995, Studies on oat gum [(1→3, 1→4)-β-D-glucan]: composition, molecular weight estimation and rheological properties. Food Hydrocolloids, 9(1), 1-7.

Dickinson, E., 2009, Hydrocolloids as emulsifiers and emulsion stabilizers. Food Hydrocolloids, 26(3), 1473-1482.

Ebringerova, A., Hromadkova, Z., Heinze, T., 2005, Hemicellulose. Polysaccharides I. Springer, 1-67.

Fennema, O. R., 1996, Food Chemistry. Madison, Wisconsin, USA: Marcel Dekker, INC.

Ghotra, B. S., Vasanthan, T., Temelli, F., 2009, Rheological properties of aqueous blends of high purity barley b-glucan with high purity commercial food gums. Food Chemistry, 117, 417–425

Hager, A. S., Ryan, L. A. M., Schwab, C. Gänzle, M. G., O’Doherty, J. V., Arendt, E. K., 2011, Influence of the soluble fibers inulin and oat β-glucan on quality of dough and bread. European Food Research and Technology, 232(3), 405-413.

Izydorczyk, M. S., Macri, L. J., MacGregor, A. W., 1998, Structure and physicochemical properties of barley non-starch polysaccharides—I. Water-extractable β-glucans and arabinoxylans. Carbohydrate Polymers, 35(3), 249-258.

Knuckles, B. E., Yokoyama, W. H., Chiu, M. M., 1997, Molecular Characterization of Barley β-Glucans by Size-Exclusion Chromatography with Multiple-Angle Laser Light Scattering and Other Detectors. Cereal Chemistry Journal, 74(5), 599-604.

Kontogiorgos, V., Biliaderis, C. G., Kiosseoglou, V., Doxastakis, G., 2004, Stability and rheology of egg-yolk-stabilized concentrated emulsions containing cereal β-glucans of varying molecular size. Food Hydrocolloids, 18(6), 987-998.

Koocheki, A., Taherian, A. R., Razavi, S. M. A., Bostan, A., 2009, Response surface methodology for optimization of extraction yield, viscosity, hue and emulsion stability of mucilage extracted from Lepidiumperfoliatum seeds. Food Hydrocolloids, 23, 2369–2379.

Kulp, K., 2000, Handbook of Cereal Science and Technology. Manhattan, Kansas, USA: Marcel Dekker, INC.

Launay, B., Doubiler, I., & Cavalier, G., 1986, Flow properties of aqueous solution and dispersions of polysaccharides. In J. A. Mitchell (Ed.), Functional properties of food macromolecules (pp. 1–78). New York: Elsevier Applied Science Publishers.

Lazaridou, A., Biliaderis, C. G., Micha-Screttas, M., Steele, B. R, 2004, A comparative study on structure–function relations of mixed-linkage (1→3), (1→4) linear β-d-glucans. Food Hydrocolloids, 18(5), 837-855.

McCleary, B. V., Glennie‐Holmes, M., 1985, Enzymic quantification of (1→ 3) (1→4)‐β‐D‐glucan in barley and malt. Journal of the Institute of Brewing, 91(5), 285-295.

Morgan, K. R., Ofman, D. J., 1998, Glucagel,1 A Gelling β-Glucan from Barley. Cereal Chemistry Journal, 75(6), 879-881.

Papageorgiou, M., Lakhdara, N., Lazaridou, A., Biliaderis, C. G., Izydorczyk, M. S., 2005, Water extractable (1→3,1→4)-β-d-glucans from barley and oats: An inter varietal study on their structural features and rheological behavior. Journal of Cereal Science, 42(2), 213-224.

Peterson, D.M., 1991, Genotype and environment effects on oat β-glucan concentration. Crop Science, 31, 1517–1520.

Roman, B. O., Alonso, E., Cocero, M. J., 2013, Ultrasound-assisted extraction of β-glucans from barley. LWT - Food Science and Technology, 50(1), 57-63.

Roman, B. O., Alonso, E., Lucas, S., 2011, Optimization of the β-glucan extraction conditions from different waxy barley cultivars. Journal of Cereal Science, 53(3), 271-276.

Shi, X. Q., Chang, K. C., Schwarz, J. G., Wiesenborn, D. P., & Shih, M. C., 1996, Optimizing pectin extraction from sunflower heads by alkaline washing. Bioresource Technology, 58(3), 291–297.

Sirghie, M. C., Kovalenko, I. V., Briggs, J. L., Fulton, B., White, P. J., 2003. Rheological and molecular properties of water soluble (1,3) (1,4)-b-D-glucans from high-b-glucan and traditional oat lines. Carbohydrate Polymers 52, 439–447

Skendi, A., Biliaderis, C. G., Lazaridou, A., Izydorczyk, M. S., 2003, Structure and rheological properties of water soluble β-glucans from oat cultivars of Avena sativa and Avenabysantina. Journal of Cereal Science, 38(1), 15-31.

Storsley, J. M., Izydorczyk, M. S., You, S., Biliaderis, C. G., Rossnagel, B., 2003, Structure and physicochemical properties of β-glucans and arabinoxylans isolated from hull-less barley. Food Hydrocolloids, 17(6), 831-844.

Temelli, F., 1997, Extraction and Functional Properties of Barley β-Glucan as Affected by Temperature and pH. Journal of Food Science, 62(6), 1194-1201.

Vaikousi, H., Biliaderis, C. G., 2005, Processing and formulation effects on rheological behavior of barley β-glucan aqueous dispersions, Food chemistry, 91(3), 505-516.

Wood, P. J., Webster, F. H., 1986, Oat β-glucan: structure, location and properties. Oats: Chemistry and technology, 121-152.

Wu, Y., Cui, S. W., Tang, J., & Gu, X., 2007, Optimization of extraction process of crude polysaccharides from boat-fruited sterculia seeds by response surface methodology. Food Chemistry, 105, 1599–1605.

Zhang, D., Doehlert, D. C., Moore, W. R., 1998, Rheological Properties of (1→3),(1→4)-β-d-Glucans from Raw, Roasted, and Steamed Oat Groats. Cereal Chemistry Journal, 75(4), 433-438