Organically Produced Grain Amaranth-Spelt Composite Flours: I. Rheological Properties of Dough

Transcription

1 Organically Produced ORIGINAL Grain SCIENTIFIC Amaranth-Spelt PAPER Composite Flours: I. Rheological Properties of Dough Organically Produced Grain Amaranth-Spelt Composite Flours: I. Rheological Properties of Dough Silva GROBELNIK MLAKAR, Matjaž TURINEK, Milojka FEKONJA, Martina BAVEC, Franc BAVEC University of Maribor, Faculty of Agriculture, Vrbaka 30, 2000 Maribor, Slovenia ( Abstract There is an interest in fortifying wheat flour with high quality protein material, such as grain amaranth (Amaranthus spp.) to improve the amino acid balance of baked products. In first part of this study the rheological properties as farinograph, exteograph and amilograph of speltamaranth composite flour were investigated. s were prepared by mixing wholemeal amaranth to wholemeal spelt flour (Triticum spelta L.) at substitution levels of 10, 20 and 30% (w/w). Sole spelt flour was used for comparison. Maximum viscosity of tested suspeio was not influenced by amaranth addition. Initial gelatinisation temperature of suspeion was lowered by amaranth flour addition, while maximum gelatinisation temperature gradually increased with amaranth substitution level from 91 o C (control) to 93 o C (10%) and 95 o C (20 and 30%). Increasing levels of amaranth flour in the blends increased water absorption and farinograph quality number mainly by increased development time and stability of dough. Because of the adhesiveness of the dough, the exteograph could not be performed for composition flour of highest amaranth substitution. However, the energy of the dough increased with amaranth flour addition mainly by increasing the resistance to exteion and maximum resistance, and decreasing the exteibility. The rheological part of the study indicates that amaranth substitutio of wholemeal spelt flour up to 20% in the blend improves some rheological properties, and strengthen the dough. Key words: composite flour, dough properties, grain amaranth, spelt Ekološka proizvodnja mješavina brašna pira i zrnatog šćira: I. Reološke karakteristike tijesta Sažetak U svijetu danas postoji težnja k poboljšavanju prehrambene vrijednosti brašna žitarica u smislu miješanja brašna s kvalitetnim bjelančevinama, kao što je i zrnati šćir (Amaranthus spp.). Na ovaj način se može poboljšati sastav aminokiselina u pekarskim proizvodima. U eksperimentima je integralno brašno pira djelomično zamijenjeno s 10, 20 i 30% integralnog brašna zrnatog šćira i određena su farinografska, ekstenzografska i amilografska svojstva.. Za usporedbu upotrijebljeno je brašno pira bez dodataka. Supstitucija brašna pira s brašnom šćira nije utjecala na maksimalni viskoznost suspenzije. Početna temperatura želatinizacije suspenzije se s povećavanjem sadržaja brašna zrnatog šćira u smjesi postupno povećavala od 91 o C (kontrola) do 93 o C (10%) i do 95 o C (20 i 30%). Povećanje količine brašna zrnatog šćira u smjesi je povećalo upijanje vode i farinografski kvalitetni broj, prije svega zbog povećanja Proceedings. 43 rd Croatian and 3 rd International Symposium on Agriculture. Opatija. Croatia (87-91) XXX) Agroecology and Ecological Agriculture 87

2 Silva GROBELNIK MLAKAR, Matjaž TURINEK, Milojka FEKONJA, Martina BAVEC, Franc BAVEC vremena razvoja i stabilnosti tijesta. Zbog adhezivnosti tijesta iz smjese s najvećim udjelom zrnatog šćira ekstenzografska analiza nije se mogla provesti, i ako je povećanje količine brašna zrnatog šćira u smjesi povećalo energijo tijesta, prije svega zbog povećanja otpornosti tijesta na rastezanje, povećanja maksimalne otpornosti tijesta i smanjenja rastezanja tijesta. Reološki dio ispitivanja pokazuje da povećanje udjela brašna zrnatog šćira do 20% u smjesi s brašnom pira poboljšava svojstva tijesta. Ključne riječi: karakteristike tijesta, mješavine brašna, pir, zrnati šćir Introduction The grain amaranth (Amaranthus spp.) is a pseudocereal, native to South America where this crop was one of the basic, as well as sacred foods in pre-columbian times. When Spanish conquered the area the native religio were banned and amaranth production and utilisation were prohibited. It was believed that beside small-sized seed this was the main reason for today's lack of knowledge and only scarce use of grain amaranth (Williams and Brenner, 1995; Bavec and Bavec, 2006a). However, the crop was rediscovered in the 1970s, and is recently attracting increased interest from an agronomic point of view, as well as nutritional and processing aspects. Among nutritional attributes of amaranth grain, it is high in protein content (ranged from %), with a better balanced set of amino acids (Becker et al., 1981; Bressani, 1994; Williams and Brenner, 1995; Leon-Camacho et al., 2001; Berghofer and Schoenlechner, 2002). These characteristics, along with relatively high fat content, uaturation, significant amount of squalene in oil, and high iron content, make amaranth particularly attractive as a blending source for processed food fortification (Pedersen et al. 1987). Rheological properties of dough are important in order to predict its behaviour during mechanical handling in the breadmaking process, and affect the quality of the resulting loaf. Among studies on composite flour containing amaranth there are only some on dough rheological characteristics (Lorenz, 1981; Breene, 1991), but they are all based on wheat flour, and virtually no research has been reported on composite speltamaranth flour. As amaranth also the spelt (Triticum spelta L.) can be classified as an alternative crop. It is old European wheat of which production has been strongly reduced in 20 th century, but recent interest in this hulled, low input wheat has increased again, and spelt is recognised as one of the most appropriate cereals for organic production (Bavec and Bavec, 2006b). Recently there is a coiderable interest in the use of spelt particularly for breadmaking purposes (Cubadda and Marconi, 2002). Present study is a part of a national research project on amaranth in which crop potential as a food has been investigated. The aim of this part was to investigate the effects of substitution of organically produced spelt by wholemeal amaranth flour on rheological properties of dough and suitability for breadmaking. Material and methods Spelt grain was obtained from Slovene biodynamic farm and processing unit Turinek, and grain amaranth (A. cruenthus cv. 'G6') from organic farm Bavec. Wholemeal spelt flour was produced by stone milling in a farm-scale mill, and wholemeal amaranth flour in a smaller stone mill (Ost-tiroler Getreide Mühlen) with narrower gap between the stones, as was recommend by Becker et al. (1986). After milling the amaranth flour was sieved through a 0.4 mm mesh. On both flour components, moisture and total ash content were analysed. For spelt flour, wet gluten, gluten index (according to standard ICC No. 155) and falling number (according to standard SIST ISO 3093) were determined. The analyses and particle size distribution are presented in Table 1. s were prepared by replacing wholemeal spelt flour with 10, 20 and 30% (w/w) of amaranth flour. Rheological properties of dough from blends were determined by farinograph and exteiograph using standard procedures for wheat, as ICC No. 115/1 and 114/1, respectively. Amylase activity was determined by amylograph according to manufacturer itruction. The rheological analyses and amylograph were run in triplicates and sole spelt flour was used for comparison. Statistical analyses were performed using the SPSS 14.0 statistical program, with the significance level set at P Duncan s test was used to determine significance of differences among mea rd Croatian and 3 rd International Symposium on Agriculture

3 Organically Produced Grain Amaranth-Spelt Composite Flours: I. Rheological Properties of Dough Table 1. Some spelt and amaranth wholemeal flour characteristics Spelt wholemeal flour Moisture (%) Ash (% in DW) Wet gluten 29.3 Gluten index 8.3 Falling number (s) 346 (62 test) Amylase activity (AU) Granulation (%) < 200 m < 132 m Amaranth wholemeal flour Results and discussion The effects of amaranth substitution for spelt flour on pasting properties of suspeion are shown in Table 2. Recorded maximum viscosity was not statistically influenced by amaranth substitution. Initial gelatinisation temperature of suspeion was lowered by amaranth flour addition, while maximum gelatinisation temperature gradually increased with amaranth substitution level from 91 o C (control) to 93 o C (10%) and 95 o C (20 and 30%). Amaranth addition to the blend increased the time to peak viscosity. With regard to Brabender farinograph, Jorgeen et al. (1997) carried out experiments on seven spelt varieties and compared them with bread wheat. Spelt samples examined were absorbed from 48.7 to 52.7% of water, which is less than obtained results in our study, while similar and very short dough stability, from 1.1 to 3.6 minutes, was reported. Increasing levels of amaranth flour for more than 10% in blends increased water absorption and development time. Dough mixing stability increases as amaranth flour was presented in the composite flours. Increasing levels of amaranth flour in the blends increased farinograph quality number (or mixing tolerance) mainly by increased development time and stability of dough, while degree of softening was more pronounced in blends of more than 10% of substitution. Development time and stability values are indicators of flour strength, thus higher values suggesting performance of stronger dough when amaranth flour is added (Table 3). Interpretation of the exteogram parameters was carried out after 45, 90 and 135 minutes of dough maturing, and is detailed in Tables 4 and 4a. Because of the adhesiveness of the dough, the Exteograph could not be performed for composite flour of the highest amaranth substitution. However, the energy of the dough increased with amaranth flour addition mainly by increasing the resistance to exteion and maximum resistance, and decreasing the exteibility. According to the obtained results ratio number and ratio number at maximum (calculated as a ratio of resistance or maximum resistance to exteibility) increased with amaranth substitution. Table 2. Brabender amylogram values of tested spelt and composite flours (spelt : amaranth in%) Maximum viscosity (AU) Begin of gelatinisation ( C) Gelatinization temperature ( C) a 91c ab 93b b 95a b 95a Levels of significance: - P 0.01; - P 0.05; not significant Mea within the column denoted with the same letter are not significantly different (Duncan, α=0.05) Time (min) 44c 45bc 47a 46b Agroecology and Ecological Agriculture 89

4 Silva GROBELNIK MLAKAR, Matjaž TURINEK, Milojka FEKONJA, Martina BAVEC, Franc BAVEC (spelt : amaranth in%) Table 3. Farinogram values of tested composite and control flour Water absorption (%) 60.0b 60.1b 61.5a 61.7a Development (min) 2.0b 2.3b 2.6a 2.7a Stability (min) 1.37c 1.47ab 1.53a 1.40bc Degree of softening b 115.3b 124.0a 129.3a Degree of softening c 127.3c 145.7b 157.7a Levels of significance: P 0.01; P 0.05 Mea within the column denoted with the same letter are not significantly different (Duncan, α=0.05) Quality number Table 4. Exteograph values (energy, resistance to exteion, exteibility) of tested composite and control dough 28.0d 33.3c 37.0b 38.7a Energy (cm 2 ) Resistance to exteion (BU) Exteibility (mm) (spelt : amaranth in%) 45' 90' 135' 45' 90' 135' 45' 90' 135' 14 b 19a 19a 18b 22a 25a c 113b 141a 104c 133b 180a 119b 148b 200a a 113a 95b 122a 118a 94b Table 4a. Exteograph values (maximum resistance, ratio number and maximum ratio number) of tested composite and control dough Maximum (BU) Ratio number Ratio number (Max.) (spelt : amaranth in%) 45' 90' 135' 45' 90' 135' 45' 90' 135' 92c 134b 166a 116c 151b 202a 131c 163b 221a 0.7c 1.0b 1.6a 0.9c 1.2b 1.9a 1.0c 1.3b 2.1a 0.8c 1.2b 1.8a 1.0c 1.3b 2.2a 1.1c 1.4b 2.3a Levels of significance: P 0.01; P 0.05; not significant Mea within the column denoted with the same letter are not significantly different (Duncan, α=0.05) Conclusio With regard to obtained results it can be concluded that amaranth substitution of wholemeal spelt flour up to 20% in the blend improves some rheological properties, and strengthe the dough. Acknowledgment Authors gratefully acknowledge the financial support of Slovene Ministry of agriculture and co-financer Žito-Intes (approved project L ). References Bavec F., Bavec M. (2006a). Grain amaranths. In: Organic Production and Use of Alternative Crops, Boca Raton: CRC Press/Taylor and Francis Group: Bavec F., Bavec M. (2006b). Spelt. In: Organic Production and Use of Alternative Crops, Boca Raton: CRC Press/Taylor and Francis Group: Becker R., Wheeler E. L., Lorenz K., Stafford A. E., Grosjean O. K., Betschart A. A., Saunders R. M. (1981). A Compositional Study of Amaranth Grain. Journal of Food Science, 46: rd Croatian and 3 rd International Symposium on Agriculture

5 Organically Produced Grain Amaranth-Spelt Composite Flours: I. Rheological Properties of Dough Becker R., Irving DW., Saunders RM. (1986). Production of debranned amaranth flour by stone milling. Food Science and Technology, 19: Berghofer E., Schoenlechner R. (2002). Grain Amaranth. In: Pseudocereals and Less Common Cereals, Grain Properties and Utilization Potential. Belton in Taylor (eds.). Springer-Verlag: Breene W. M. (1991). Food uses of grain amaranth. Cereal Foods World, 36, 5: Bressani R. (1994). Composition and nutritional of amaranth. In: Amaranth - Biology, Chemistry, and Technology. Peredes-López (ed.). London, CRC Press: Cubadda R., Marconi E. (2002). Spelt wheat. In: Pseudocereals and Less Common Cereals, Grain Properties and Utilization Potential. Belton in Taylor (eds.). Springer-Verlag: Jorgeen J. R., Olsen C. C., Christiaen S. (1997). Cultivation and quality assessment of spelt (Triticum spelta L.) compared with winter wheat (Triticum aestivum L.). In: Small grain cereals and pseudo-cereals. Stolen O., Bruhn K., Pithan K., Hill J. (eds). European Commission, Luxemburg: Leon-Camacho M., Garcia-Gonzalez D. L., Aparicio R. (2001). A detailed study of amaranth (Amaranthus cruentus L.) oil fatty profile. Eur Food Technol, 213: Lorenz K. (1981). Amaranthus hypochondriacus Characteristics of the starch and baking potential of the flour. Staerke, 33: Pedersen B., Kalinowski L. S., Eggum B. O. (1987). The nutritive value of amaranth grain (Amaranthus caudatus) 1. Protein and minerals of row and processed grain. Plant foods for Human Nutrition, 36: SIST ISO 3093 Cereals Determination of falling number SPSS 14.0 statistical program (2006). SPSS Inc., Chicago Standard Methods of the International Association for Cereal Science and Technology (ICC). (1998). Methods 115/1, 114/1, 155. Verlag Moritz Schäfer, Detmold Williams J. T., Brenner D. (1995). Grain amaranth (Amaranthus species). In: Underutilized Crops: Cereals and Pseudocereals. Williams J. T. (ed), Chapman & Hall, London: sa2008_0109 Agroecology and Ecological Agriculture 91