ISSN 0355-1180 UNIVERSITY OF HELSINKI Department of Food and Environmental Sciences EKT Series 1632 Effect of extrusion cooking on the nutritional properties of amaranth, quinoa, kañiwa and lupine Lakshminarasimhan Sundarrajan Helsinki 2014 Tiedekunta/Osasto Fakultet/Sektion – Faculty Laitos/Institution– Department Faculty of Agriculture and Forestry Department of Food and Environmental Sciences Tekijä/Författare – Author Lakshminarasimhan Sundarrajan Työn nimi / Arbetets titel – Title Effect of extrusion cooking on the nutritional properties of amaranth, quinoa, kañiwa and lupine Oppiaine /Läroämne – Subject Food Sciences (Food Bioprocessing) Työn laji/Arbetets art – Level Aika/Datum – Month and year Sivumäärä/ Sidoantal – Number of pages M.Sc. Thesis January 2014 98 Tiivistelmä/Referat – Abstract Amaranth, quinoa, kañiwa and lupine are good sources of protein, fat, dietary fibre and bioactive compounds. The literature review deals with the nutritional properties and the stability of bioactive compounds and the effect of extrusion cooking on amaranth, quinoa, kañiwa and lupine. The main aim of this study was to (1) chemically characterize amaranth, quinoa, kañiwa and lupine, and (2) to determine the effect of extrusion cooking on the nutritional properties and the stability of bioactive compounds. Extrudates were processed using twin screw extruder at two different extrusion temperatures (140 and 160 °C) containing two different contents of tested flour mixtures (20 and 50%). The raw materials and the extrudates were stored at -18 °C and chemically characterized to determine fatty acid composition, tocopherol composition and total phenolic acid content. Fatty acid composition was determined using GC while tocopherol composition was detected using HPLC. The total phenolic acid content was analyzed using Folin-Ciocalteu method. The protein and dietary fibre content in lupine accounted for 29 and 50 g/100 g d.m., respectively. The extrudates containing 50% lupine and processed at 140 °C possessed higher content of oleic, linoleic and linolenic fatty acids. At higher content of tested flours, extrusion cooking at 160 °C resulted in better retention of unsaturated fatty acids in the extrudates of amaranth, kañiwa and quinoa. Higher extrusion temperatures resulted in lower retention of tocopherols in all the extrudates. The total phenolic acid resulted in higher contents in the extrudates of kañiwa when compared to other extrudates. At higher seed contents of tested flours (%), higher retention of total phenolic acid was achieved during extrusion cooking at 140 °C in the extrudates of amaranth, quinoa and kañiwa. This study showed that extrusion conditions could be optimized in order to obtain lesser effects on the nutritional properties and better retention of bioactive compounds. The research study provides supportive information for obtaining gluten-free cereal snack products with lower glycemic index. Avainsanat – Nyckelord – Keywords Amaranth, quinoa, kañiwa, lupine, extrusion, nutritional properties, bioactive compounds Säilytyspaikka – Förvaringställe – Where deposited The Digital Repository of University of Helsinki, Helda Muita tietoja – Övriga uppgifter – Additional information EKT Series 1632 PREFACE The Master’s thesis research was carried out in cooperation with the Food chemistry and Food technology under the Department of Food and Environmental studies at University of Helsinki, Finland. The present research study was a part of Jose Martin Ramos Diaz’s PhD project and the study took approximately a year for its completion (January 2013- 2014). The research group comprised of PhD. University Lecturer Kirsi Jouppila, PhD University lecturer Anna-Maija Lampi and M.Sc. Jose Martin Ramos Diaz. I am highly indebted to my supervisors PhD. University Lecturer Kirsi Jouppila, PhD University lecturer Anna-Maija Lampi and M.Sc. Jose Martin Ramos Diaz for giving me this wonderful opportunity to pursue my Master’s thesis research in the field of Food Sciences and also helping me in arranging financial support during my research study. I really thank PhD University lecturer Anna-Maija Lampi for creating a lovely environment and offering tireless help and support during my laboratory work. I would also like to thank PhD. University Lecturer Seppo Tenitz for guiding me to learn the statistical analysis and helping me whenever needed. I gratefully thank the University of Helsinki for giving the opportunity to pursue my Master’s degree in the field of Food sciences as an International student. I also gratefully thank the staff of Food chemistry for helping me during the course of laboratory work. I would like to thank my colleagues and fellow classmates Anish, Maheswor, Suresh, Sriyapathy and Ashok for continuously offering their support and motivation during the research study. I am highly indebted to WCC cricket team, friends and my family members for delivering their constant support and encouragement. Helsinki, January 2014 Lakshminarasimhan Sundarrajan TABLE OF CONTENTS 1 INTRODUCTION .................................................................................................................. 5 2 LITERATURE REVIEW........................................................................................................ 7 2.1 General aspects of amaranth, lupine, kañiwa and quinoa ................................................ 7 2.1.1 Origin of amaranth, lupine, kañiwa and quinoa ......................................................... 7 2.1.2 Traditional uses and current utilization of the seeds.................................................. 8 2.2 Nutritional properties ....................................................................................................... 9 2.2.1 Protein and amino acid composition ........................................................................ 11 2.2.2 Total fat and fatty acid composition ........................................................................ 14 2.2.3 Carbohydrates and dietary fiber content .................................................................. 16 2.3 Bioactive components and micronutrients ..................................................................... 18 2.3.1 Phenolic compounds and flavonoids ....................................................................... 19 2.3.2 Vitamins and minerals ............................................................................................. 23 2.4 Antinutrients ................................................................................................................... 27 2.5 Extrusion ........................................................................................................................ 28 2.5.1 Processing parameters affecting extruded snacks .................................................... 29 2.5.2 Physical and chemical changes during extrusion .................................................... 30 2.5.3 Effect of extrusion on the nutritional properties of extruded snacks ....................... 31 2.5.4 Effect of extrusion on the antinutritional properties of extruded snacks ................. 35 2.6 The effect of other processing methods on the nutritional properties of amaranth, quinoa, kañiwa and lupine ................................................................................................................. 37 3 Experimental study................................................................................................................ 38 3.1 Aims and overview of the study ..................................................................................... 38 3.2 Materials ......................................................................................................................... 40 3.3 Methods .......................................................................................................................... 40 3.3.1 Chemical characterization of raw materials and extrudates of amaranth, quinoa, lupine and kañiwa ............................................................................................................. 40 3.3.2 Analysis of bioactive compounds of flour samples and extrudate samples of amaranth, quinoa, lupine and kañiwa ............................................................................... 44 3.3.3 Statistical analysis .................................................................................................... 46 3.4 Results ............................................................................................................................ 47 3.4.1 Chemical composition of amaranth, quinoa, kañiwa, polenta and lupine ............... 47 3.4.2 Estimation of bioactive compounds of flour samples and extrudates ..................... 51 3.4.3 PCA and PLS data analysis of extrudates ................................................................ 57 3.5 Discussion ...................................................................................................................... 64 3.5.1 Chemical composition of raw materials of amaranth, quinoa, kañiwa and lupine .. 64 3.5.2 Effect of extrusion on fatty acid composition of amaranth, quinoa, kañiwa and lupine ................................................................................................................................ 67 3.5.3 Effect of extrusion on tocopherol content of amaranth, quinoa, kañiwa and lupine 69 3.5.4 Effect of extrusion on total phenolic content of amaranth, quinoa, kañiwa and lupine ...............................................................................................................................