Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and soya bean

Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and soya bean

LWT - Food Science and Technology xxx (2014) 1e4 Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.e...

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LWT - Food Science and Technology xxx (2014) 1e4

Contents lists available at ScienceDirect

LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt

Research note

Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and soya bean €hr a, 1, Anita Fechner a, 1, Katrin Hasenkopf b, Stephanie Mittermaier b, Melanie Ba Gerhard Jahreis a, * a b

Friedrich Schiller University Jena, Department of Nutritional Physiology, Dornburger Straße 24, 07743 Jena, Germany Fraunhofer Institute for Process Engineering and Packaging IVV, Giggenhauser Straße 35, 85354 Freising, Germany

a r t i c l e i n f o

a b s t r a c t

Article history: Received 20 December 2013 Received in revised form 14 April 2014 Accepted 8 May 2014 Available online xxx

With the objective of promoting the cultivation, usage, and consumption of lupin, in the present study, the chemical and fibre composition of dehulled seeds of seven cultivars of different lupin species (Lupinus angustifolius, Lupinus albus and Lupinus luteus) was determined in comparison to pea (Pisum sativum) and soya bean (Glycine max). The mean protein content of lupin was significantly higher compared to pea (P < 0.001) and similar to soya bean, whereas the proportion of calculated carbohydrates was lowest for lupin (P < 0.001). The content of total dietary fibre and of calculated soluble fibre was higher for lupin compared to pea (P  0.003) and soya bean (P  0.013). In contrast to the existing literature, the soluble fibre content of lupin contributed about 75% of the total dietary fibre. In conclusion, dehulled lupin seeds can be considered as a valuable source of plant protein and dietary fibre, while simultaneously being low in carbohydrates. Therefore, lupin should be exploited more efficiently within human and also animal nutrition. In further studies, the impact of dehulling lupin seeds and of using different methodologies in fibre analyses on the results of chemical composition should be elucidated. © 2014 Elsevier Ltd. All rights reserved.

Keywords: Legume Lupin Dietary fibre Protein Chemical composition

1. Introduction In recent years, numerous human intervention studies have demonstrated that both protein and dietary fibre of sweet lupin €hr, Fechner, Kiehntopf, & exert several physiological benefits (Ba €hr, Fechner, Kr€ Jahreis, 2014; Ba amer, Kiehntopf, & Jahreis, 2013; Duranti & Morazzoni, 2011; Fechner, Fenske, & Jahreis, 2013; Fechner, Kiehntopf, & Jahreis, 2014; Fechner, Schweiggert, Hasenkopf, & Jahreis, 2011; Johnson, Chua, Hall, & Baxter, 2006). Despite various physiological, ecological and technofunctional advantages of lupin, to date, the use of this legume in human nutrition is low (Hall, Thomas, & Johnson, 2005). Moreover, there are only few reports on the chemical composition of dehulled seeds of lupin. However, for use in human nutrition, lupin

seeds are generally dehulled. The thick seed hull, which accounts for ca. 25% of lupin seed on a wet weight basis (Evans, Cheung, & Cheetham, 1993) was found to differ considerably from the lupin kernel in crude protein, fat and crude fibre (Hove, 1974; Pisarikova, Zraly, Bunka, & Trckova, 2008) as well as in dietary fibre composition (Guillon & Champ, 2002; Pisarikova & Zraly, 2010). Therefore, the present study aimed to provide data concerning the chemical composition of dehulled seeds of three lupin species (Lupinus angustifolius, Lupinus albus and Lupinus luteus) and to compare these with that of dehulled pea (Pisum sativum) and dehulled soya bean (Glycine max). 2. Material and methods 2.1. Processing of legume seeds

Abbreviations: DM, dry matter; FM, fresh matter; TDF, total dietary fibre; SDF, soluble dietary fibre; IDF, insoluble dietary fibre. * Corresponding author. Tel.: þ49 3641 949610; fax: þ49 3641 949612. €hr), [email protected] E-mail addresses: [email protected] (M. Ba de (A. Fechner), [email protected] (K. Hasenkopf), stephanie. [email protected] (S. Mittermaier), [email protected] (G. Jahreis). 1 These authors contributed equally to this work.

Legume seeds of seven cultivars of sweet lupin (L. angustifolius, L. albus and L. luteus), three cultivars of pea (P. sativum), and three cultivars of soya bean (G. max) were processed to kernel preparations by the Fraunhofer Institute for Process Engineering and Packaging (Freising, Germany). Therefore, the cleaned seeds were

http://dx.doi.org/10.1016/j.lwt.2014.05.026 0023-6438/© 2014 Elsevier Ltd. All rights reserved.

€hr, M., et al., Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and Please cite this article in press as: Ba soya bean, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.05.026

€hr et al. / LWT - Food Science and Technology xxx (2014) 1e4 M. Ba

2 Table 1 Compositional data of the dehulled legume seeds. Species

Lupinus angustifolius

Lupinus albus Lupinus luteus Mean value ± SD Pisum sativum

Mean value ± SD Glycine max

Mean value ± SD

Cultivar

Probore Borlue Boreginee Vitabore TypTopf Lublancg Bornale Attikah Lidoi Santanah Marlinh Malandroj Hefengj

DM

Ash

Protein

Fat

Carbohydratesd

n¼2

n¼2

n¼2

n¼1

n¼1

[g/100 g FM]

[g/100 g DM]

[g/100 g DM]

[g/100 g DM]

[g/100 g DM]

7.2 6.8 8.3 9.8 1.4a 12.7 8.2 8.8 ± 2.2b 2.4 3.5 12.1 6.0 ± 5.3 6.5a 3.3a 3.1a 4.3 ± 1.9c

8.0 6.1 8.8 8.7 e 4.5 10.4 7.8 ± 2.1 56.5 61.1 40.5 52.7 ± 10.8 e e e e

90.6 87.5 89.2 90.9 88.8 91.2 89.2 89.6 91.4 88.0 88.0 89.1 92.1 91.2 91.8 91.7

± 0.3 ± 0.1 ± 0.1 ± 0.0 ± 0.2 ± 0.1 ± 0.1 ± 1.3 ± 0.0 ± 0.2 ± 0.9 ± 2.0 ± 0.1 ± 0.2 ± 0.1 ± 0.4

3.84 4.17 3.72 4.11 4.46 5.01 5.09 4.34 2.82 3.15 3.22 3.06 7.04 6.33 6.48 6.62

± 0.01 ± 0.10 ± 0.09 ± 0.05 ± 0.09 ± 0.02 ± 0.16 ± 0.54b ± 0.06 ± 0.14 ± 0.03 ± 0.21c ± 0.03 ± 0.04 ± 0.03 ± 0.37a

44.2 42.8 40.0 38.8 52.9 45.3 55.3 45.6 23.2 23.1 25.2 23.8 47.5 47.8 52.1 49.2

± 0.4 ± 0.3 ± 1.0 ± 0.4 ± 0.1 ± 0.5 ± 0.8 ± 6.2a ± 0.5 ± 0.1 ± 0.2 ± 1.2b ± 1.8 ± 0.8 ± 0.3 ± 2.6a

FM, fresh matter; DM, dry matter. Means within the same column with different online letters (a,b,c) are significantly different (P  0.05). e Carbohydrates could not be calculated due to deoiling. a Flaked seeds were deoiled using hexane. b Means and SD of fat were calculated without the fat content for the deoiled cultivar of lupin. c Mean and SD of the deoiled cultivars of soya bean. d Carbohydrates were calculated as follows: 100  (ash þ protein þ fat þ total dietary fibre). e supplied by Saatzucht Steinach GmbH & Co. KG (Steinach, Germany). f n Chilena de Lupino A.G. (Temuco, Chile). supplied by Seeds Asociaco g supplied by Vermarktungsgesellschaft Bioland Naturprodukte mbH & Co. KG (Bad Kreuznach, Germany). h supplied by Thüringer Zentrum Nachwachsende Rohstoffe der TLL (Dornburg-Camburg, Germany). i €bisch Hall, Germany). supplied by Pflanzenzucht Oberlimpurg (Schwa j supplied by Purvegan GmbH (Ramsen, Germany).

dehulled using an underdrifter disc sheller (Streckel & Schrader KG, Hamburg, Germany). Hulls and kernels were separated using a zigzag air-classifier (Multiplex, Hosokawa Alpine AG, Augsburg, Germany). The kernels were flaked using a flaking mill with coolable rollers (Streckel & Schrader KG, Hamburg, Germany). Finally, the flakes were grinded to fine flour using an impact mill. 2.2. Chemical composition The nutrient composition of the legume kernel preparations was analysed by standard methods of the Association of Official Analytical Chemists (AOAC, 1990). The contents of insoluble dietary fibre (IDF; estimated by neutral detergent fibre analysis) and total dietary fibre (TDF) were determined by standard procedures according to Van Soest, Robertson, and Lewis (1991) and AOAC 985.29 (enzyme set: BIOQUANT® TDF, Merck, Darmstadt, Germany; filter machinery: Fibertec™ E, FOSS Analytical, Hillerroed, Denmark), respectively. The content of carbohydrates was calculated as follows: carbohydrates ¼ 100  (ash þ protein þ fat þ TDF). Soluble dietary fibre (SDF) content was determined by deducting IDF from TDF.

comparison to other legumes used in human nutrition, lupin, together with soya bean, contain high proportions of protein (Kohajdova, Karovicova, & Schmidt, 2011). Moreover, lupin protein appears to positively impact cardiovascular risk factors, such as €hr et al., 2014, 2013; Naruszewicz, hypercholesterolaemia (Ba Nowicka, Klosiewicz-Latoszek, Arnoldi, & Sirtori, 2006; Sirtori et al., 2012; Weisse et al., 2010) and hypertension (B€ ahr et al., 2013; Naruszewicz et al., 2006). The mean content of minerals in lupin, reflected by the ash proportion, was found to be between that of pea (P ¼ 0.006) and soya bean (P < 0.001). Besides having a low content of available carbohydrates per se, lupin flour positively affects postprandial glycaemic (Dove et al., 2011; Hall et al., 2005) and insulinaemic response (Hall et al., 2005) when added to meals rich in starch. The content of TDF as well as of calculated SDF was higher for lupin compared to pea (P  0.003) and soya bean (P  0.013; Table 2). Numerous studies have observed that consumption of legume kernel fibres might contribute to the prevention of colorectal cancer and improve colonic health in general (Fechner et al., 2013; Johnson et al., 2006; Schweizer et al., 1983). 3.2. Comparison with previous analyses

2.3. Statistical analyses After testing for normal distribution, differences in chemical composition between lupin, pea, and soya bean were estimated applying t-test for independent samples, being statistically significant with P  0.05 (SPSS 19.0, SPSS Inc., Chicago, USA). 3. Results and discussion 3.1. Chemical composition of lupin vs. pea and soya bean The mean protein content of lupin was significantly higher compared to pea (P < 0.001) and similar to soya bean (Table 1). In

In the present study, the mean values of DM, ash, protein, fat, and calculated carbohydrates of lupin were largely comparable with the few data that is available on dehulled lupin seeds of L. angustifolius (Belski, 2012; Evans et al., 1993; Hove, 1974) and L. albus (Hove, 1974). The contents of TDF were comparable to that analysed in the kernels of three cultivars of L. angustifolius (Evans et al., 1993), whereas Pisarikova and Zraly (2010) detected higher proportions of TDF in dehulled seeds of L. albus (43 g/100 g DM). In contrast to the existing literature (Belski, 2012; Evans et al., 1993; Guillon & Champ, 2002; Kohajdova et al., 2011; Pisarikova & Zraly, 2010), which reports small proportions of SDF for lupin, in the present study, the SDF contributed about 75% of the TDF. The

€hr, M., et al., Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and Please cite this article in press as: Ba soya bean, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.05.026

€hr et al. / LWT - Food Science and Technology xxx (2014) 1e4 M. Ba

3

Table 2 Dietary fibre composition of the dehulled legume seeds. Species

Lupinus angustifolius

Lupinus albus Lupinus luteus Mean value ± SD Pisum sativum

Mean value ± SD Glycine max

Mean value ± SD

Cultivar

Probor Borlu Boregine Vitabor TypTop Lublanc Bornal Attika Lido Santana Marlin Malandro Hefeng

TDF

SDFa

IDF

Hemicellulose

n¼2

n¼1

n¼3

n¼3

[g/100 g DM]

[g/100 g DM]

[%TDF]

[g/100 g DM]

27.95 29.13 31.74 28.10 21.32 24.85 15.64 25.53 ± 5.48(a) 3.83 1.53 11.79 5.72 ± 5.38(b) 12.10 12.17 2.89 9.05 ± 5.34(b)

76.2 72.7 81.1 73.1 75.1 76.4 74.4 75.6 ± 2.8 25.4 16.9 62.3 34.8 ± 24.1 57.6 51.6 21.3 43.5 ± 19.5

8.71 10.97 7.39 10.33 7.07 7.66 5.37 8.22 11.26 7.57 7.14 8.66 9.22 11.41 10.68 10.44

36.7 40.1 39.1 38.4 28.4 32.5 21.0 33.7 15.1 9.1 18.9 14.4 21.6 23.6 13.6 19.6

± 0.9 ± 0.4 ± 0.2 ± 0.6 ± 0.1 ± 0.7 ± 0.4 ± 7.0(a) ± 0.7 ± 0.8 ± 0.4 ± 5.0(b) ± 1.2 ± 0.1 ± 0.6 ± 5.3(b)

± 0.58 ± 0.31 ± 0.26 ± 0.53 ± 0.11 ± 0.22 ± 0.01 ± 1.94 ± 0.07 ± 0.39 ± 0.30 ± 2.26 ± 0.07 ± 0.44 ± 0.20 ± 1.12

[%TDF]

[g/100 g DM]

23.8 27.3 18.9 26.9 24.9 23.6 25.6 24.4 ± 2.8 74.6 83.2 37.7 65.2 ± 24.2 41.3 48.4 78.8 56.2 ± 19.9

3.04 2.81 1.92 4.49 3.82 2.82 1.55 2.92 9.04 5.51 5.19 6.58 5.38 6.24 4.17 5.26

± 0.58 ± 0.31 ± 0.26 ± 0.53 ± 0.11 ± 0.22 ± 0.01 ± 1.02(b) ± 0.07 ± 0.39 ± 0.30 ± 2.13(a) ± 0.17 ± 0.44 ± 0.20 ± 1.04(a)

[%TDF] 8.3 7.0 4.9 11.7 13.5 8.7 7.4 8.8 ± 2.9 59.9 60.6 27.4 49.3 ± 18.9 24.9 26.4 30.7 27.4 ± 3.0

DM, dry matter; TDF, total dietary fibre; SDF, soluble dietary fibre; IDF, insoluble dietary fibre. Means within the same column with different online letters (a,b) are significantly different (P  0.05). a SDF was calculated as follows: TDF e IDF.

following could have caused these discrepancies: Dehulling of lupin seeds might have led to a decrease in the proportion of IDF when compared to the whole seeds, thereby increasing the SDF proportion. Pisarikova and Zraly (2010) did observe significantly lower IDF proportions in dehulled compared to whole lupin seeds. Moreover, the applied method in our study could have produced diverging results due to the deviating methodology of Van Soest et al. (1991). This method is based on neutral detergent fibre analysis rather than on procedures that directly analyse proportions of SDF and IDF such as AOAC 991.43. Thus, further research on lupin is needed to not only define precisely SDF and IDF proportions and to evaluate the effect of dehulling on chemical composition of the lupin seeds, but also to clarify, which chemical components are responsible for the positive effects that have been observed in several human intervention studies after lupin consumption. 4. Conclusion Among the analysed legumes, dehulled lupin seeds were found to be highest in TDF. Moreover, lupin seeds contained high proportions of protein similar to soya bean. Thus, dehulled lupin seeds can be considered as a valuable source of plant protein and dietary fibre, while simultaneously being low in carbohydrates. Since, furthermore, lupin appears to bear various physiological, technofunctional, and ecological benefits, this legume should be exploited more efficiently within human and also animal nutrition. Acknowledgements We thank the Federal Ministry of Education and Research (grant no. 0315683C and 0313824B) for financial support and K. Gregor and U. Helms for technical assistance. References AOAC. (1990). Official methods of analysis of the Association of Official Analytical Chemists (15th ed.). Washington, DC; USA: Association of Official Analytical Chemists. €hr, M., Fechner, A., Kiehntopf, M., & Jahreis, G. (2014). Consuming a mixed diet Ba enriched with lupin protein beneficially affects plasma lipids in

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€hr, M., et al., Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and Please cite this article in press as: Ba soya bean, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.05.026

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Sirtori, C. R., Triolo, M., Bosisio, R., Bondioli, A., Calabresi, L., De Vergori, V., et al. (2012). Hypocholesterolaemic effects of lupin protein and pea protein/fibre combinations in moderately hypercholesterolaemic individuals. British Journal of Nutrition, 107(8), 1176e1183. Van Soest, P. J., Robertson, J. B., & Lewis, B. A. (1991). Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science, 74(10), 3583e3597.

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€hr, M., et al., Chemical composition of dehulled seeds of selected lupin cultivars in comparison to pea and Please cite this article in press as: Ba soya bean, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.05.026