Main Article Content

Mariya Dushkova Anna Koleva Dobromir Genev Apostol Simitchiev Todorka Petrova Miroslava Kakalova


The purpose of this work was to study the effect of pumpkin flour (10% and 20%), moisture content of initial mixture (14% and 20%) and working screw speed (180 min-1 and 220 min-1) on the physicochemical (expansion, density, hardness, colour) and sensory characteristics of rice extrudates enriched with pumpkin produced on a single screw extruder. The chemical composition before and after extrusion was also determined. The ash, lipids, reducing sugars, total sugars and total protein remained unchanged before and after extrusion while the carotenoids decreased after extrusion. The increase in the pumpkin flour led to a decrease in the expansion and lightness, and an increase in the density, hardness and redness of extrudates. The effect of the moisture content was inversely proportional on the expansion and redness, while it was directly proportional on the density, hardness and lightness. The screw speed increased the expansion, hardness and lightness of the extrudates, decreased the redness and had no significant effect on the density. The highest sensory score was achieved at a moisture content 14%, pumpkin flour 10% and screw speed 220 min-1. The moisture content had the most significant effect on the characteristics of the extrudates. 

Article Details


Altan A., McCarthy K., Maskan M. Twin-screw extrusion of barley-grape pomace blends: extrudate characteristics and determination of optimum processing conditions. Journal of Food Engineering, 2008, 89(1): 24-32.

Alvarez-Jubete L., Wijngaard H., Arendt E. K., Gallagher E. Polyphenol composition and in vitro antioxidant activity of amaranth, quinoa buckwheat and wheat as affected by sprouting and baking. Food Chemistry, 2010, 119(2): 770-778.

AOAC Official Method 945.16. Oil in cereal adjuncts. Gaithersburg, MD, USA, AOAC International,2017.

Badrie N., Mellowes W. Effect of extrusion variables on cassava extrudates. Journal of Food Science, 1991, 56(5): 1334-1337.

Bisharat G.I., Oikonomopoulou V.P., Panagiotou N.M., Krokida M.K., Maroulis Z.B. Effect of extrusion conditions on the structural properties of corn extrudates enriched with dehydrated vegetables. Food Research International, 2013, 53(1): 1-14.

Capriles V.D., Soares R.A.M., Pinto e Silva M.E.M., Arêas J.A.G. Effect of fructans-based fat replacer on chemical composition, starch digestibility and sensory acceptability of corn snacks. International Journal of Food Science and Technology, 2009, 44(10): 1895-1901.

Carbonell-Capella J. M., Buniowska M., Barba F. J., Esteve M.J., Frigola A. Analytical methods for determining bioavailability and bioaccessibility of bioactive compounds from fruits and vegetables. Comprehensive Reviews in Food Science and Food Safety, 2014, 13(2): 155-171.

Černiauskienė J., Kulaitienė J., Danilčenko H., Jarienė E., Juknevičienė E. Pumpkin fruit flour as a source for food enrichment in dietary fiber. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 2014, 42(1): 19-23.

Chakraborty S., Singh D., Kumbhar B., Chakraborty S. Millet-legume blended extrudates characteristics and process optimization using RSM. Food and Bioproducts Processing, 2011, 89(4): 492-499.

Dehghan-Shoar Z., Hardacre A., Brennan C. The physico-chemical characteristics of extruded snacks enriched with tomato lycopene. Food Chemistry, 2010, 123(4): 1117-1122.

Desrumaux A., Bouvier J. M., Burri J. Effect of free fatty acids addition on corn grits extrusion cooking. Cereal Chemistry, 1999, 76(5): 699-704.

Ding Q., Ainsworth P., Plunkett A., Tucker G., Marson H. The effect of extrusion conditions on the functional and physical properties of wheat - based expanded snacks. Journal of Food Engineering, 2006, 73(2): 142-148.

Ding Q., Ainsworth P., Tucker G., Marson H. The effect of extrusion conditions on the physicochemical properties and sensory characteristics of rice - based expanded snacks. Journal of Food Engineering, 2005, 66(3): 283-289.

Fernandez-Orozco R., Frias J., Zielinski H., Piskula M.K. Kinetic study of the antioxidant compounds andantioxidantcapacity during germination of Vigna radiata cv. emmerald, Glycine max cv. jutro and Glycine max cv. Merit. Food Chemistry, 2008, 111(3): 622-630.

Frias J., Miranda M. L., Doblado R., Vidal-Valverde C. Effect of germination and fermentation on the antioxidant vitamin content and antioxidant capacity of Lupinus albus L. var. Multolupa. Food Chemistry, 2005, 92(2): 211-220.

Gat Y., Ananthanarayan L. Effect of extrusion process parameters and pregelatinized rice flour on physicochemical properties of ready-to-eat expanded snacks. Journal of Food Science and Technology, 2015, 52(5): 2634-2645.

Genev D., Dushkova M., Koleva A., Simitchiev A., Kakalova M. Investigation of specific mechanical energy during extrusion of rice flour enriched with dried pumpkin. Scientific Works of University of Food Technologies, 2019, 66(1): 69-77. Available at:

Hagenimana A., Ding X., Fang T. Evaluation of rice flour modified by extrusion cooking. Journal of Cereal Science, 2006, 43: 38-46.

Hien T.T., Minh N.T. Enhancing the extraction of pumpkin seed (Cucurbita pepo L) for increasing oil yield and its phytosterol content. Food Science and Applied Biotechnology, 2021, 4(1): 6-13.

Higby, W.K. (1962). A simplified method for determination of some aspects of the carotenoid distribution in natural and carotene fortified orange juice. Journal of Food Science, 27(1): 42-49.

Hui Y.H., Ghazala S., Graham D.M., Murrell K.D., Nip W.-K. Handbook of Vegetable Preservation and Processing. Series: Food Science and Technology (First Edition). Marcel Dekker, CRC Press. 2003, 752 pages. ISBN-13‏:‎ 978-0824743017; ISBN-10: 0824743016

Ilo S., Berghofer E. Kinetics of Colour Changes During Extrusion Cooking of Maize Grits, Journal of Food Engineering, 1999, 39(1): 73-80.

ISO 20483:2013 Cereals and pulses - Determination of the nitrogen content and calculation of the crude protein content - Kjeldahl method. Geneva, Switzerland: International Organization for Standardization (ISO), 2013.

ISO 2171:2007 Cereals, pulses and by - products - Determination of ash yield by incineration. Geneva, Switzerland: International Organization for Standardization (ISO), 2007.

ISO 712:2009 Cereals and cereal products - Determination of moisture content - Reference method. Geneva, Switzerland: International Organization for Standardization (ISO), 2009.

Kadan R. S., Bryant R. J., Pepperman A. B. Functional properties of extruded rice flours. Journal of Food Science, 2003, 68(5): 1669-1672.

Kayahara H., Tsukahara K., Tatai T. Flavor, health and nutritional quality of pre-germinated brown rice. In: Food Flavors and Chemistry: Advances of the New Millennium (A.M. Spanier, F. Shahidi, T.H. Parliment, C. Mussinan, C.T. Ho, E.T. Contis Eds). Proceedings of the 10th International Flavor Conference; 2000 May 4-7, Paros, Greece. Royal Society of Chemistry, Cambridge, UK, vol. 274, 2001, pp. 546-551. ISBN 085-4-04875-8

Leonel M., Santos de Freitas T., Mischan M. Physical characteristics of extruded cassava starch. Scientia Agricola (Piracicaba, Braz.), 2009, 66(4): 486-493.

Lin Y., Yeh C., Lu S. Evaluation on quality indices and retained tocopherol contents in the production of the rice-based cereal by extrusion. Journal of Food and Drug Analysis, 2002, 10(3): 183-187.

Meng X., Threinen D., Hansen M., Driedger D. Effects of extrusion conditions on system parameters and physical properties of a chickpea flour - based snack. Food Research International, 2010, 43(2): 650-658.

Mezreb K., Goullieux A., Ralainirina R., Queneudec M. Effect of sucrose on textural properties of corn and wheat extrudates. Carbohydrate Polymers, 2006, 64(1): 1-8.

Milan-Carrillo J., Reyes-Moreno C., Armienta-Rodelo E., Carabez-Trejo A., Mora-Escobedo R. Physicochemical and nutritional characteristics of extruded flours from fresh and hardened chickpeas (Cicer arietinum L). LWT - Food Science and Technology, 2000, 33(2): 117-123.

Nor N.M., Carr A., Hardacre A., Brennan C.S. The development of expanded snack product made from pumpkin flour-corn grits: effect of extrusion conditions and formulations on physical characteristics and microstructure. Foods, 2013, 2(2): 160-169.

Peressini D., Foschia M., Tubaro F., Sensidoni A. Impact of soluble dietary fibre on the characteristics of extruded snacks. Food Hydrocolloids, 2015, 43: 73-81.

Phillips E., Chhinnan M., Kennedy M. Effect of feed moisture and barrel temperature on physical properties of extruded cow pea meal. Journal of Food Science, 1984, 49(3): 916-921.

Poliszko N., Kowalczewski P.Ł., Rybicka I. The effect of pumpkin flour on quality and acoustic properties of extruded corn snacks. Journal of Consumer Protection and Food Safety, 2019, 14(6): 121-129.

Promsakha na Sakon Nakhon P., Jangchud K., Jangchud A., Charunuch C. Optimization of pumpkin and feed moisture content to produce healthy pumpkin-germinated brown rice extruded snacks. Agriculture and Natural Resources, 2018, 52(6): 550-556.

Sgaramella S., Ames J. The development and control of colour in extrusion cooked foods. Food Chemistry, 1993, 46(2): 129-132.

Stojceska V., Ainsworth P., Plunkett A., İbanoğlu Ş. The effect of extrusion cooking using different water feed rate on the quality of ready-to-eat snacks made from food by-products. Food Chemistry, 2009, 114(1): 226-232.

Toshkov N., Nenov N., Bozadjiev B., Delchev N., Valov E. Extrusion of wheat semolina and cocoa shells. Food Science and Applied Biotechnology 2021, 4(2): 177-182.

Wang N., Maximiuk L., Toews R. Pea starch noodles: effect of processing variables on characteristics and optimisation of twin-screw extrusion process. Food Chemistry, 2012, 133(3): 742-753.

How to Cite
DUSHKOVA, Mariya et al. Physicochemical and sensory characteristics of extrudates from rice enriched with pumpkin. Food Science and Applied Biotechnology, [S.l.], v. 6, n. 1, p. 103-116, mar. 2023. ISSN 2603-3380. Available at: <>. Date accessed: 13 july 2024. doi: