Pol. J. Food Nutr. Sci., 2014, Vol. 64, No. 2, pp. 75–89 DOI: 10.2478/v10222-012-0098-9 http://journal.pan.olsztyn.pl Review article Section: Food Quality and Functionality Non-Nutritive Compounds in Fabaceae Family Seeds and the Improvement of Their Nutritional Quality by Traditional Processing – a Review Piotr Gulewicz1*, Cristina Martinez-Villaluenga2, Małgorzata Kasprowicz-Potocka3, Juana Frias2 1 Adam Mickiewicz University Foundation Poznan Science and Technology Park 46 Rubież St., 61–612 Poznań, Poland 2Department of Characterization, Quality and Safety, Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain 3Department of Animal Nutrition and Feed Management, University of Life Sciences, Wołyńska 33, 60–637 Poznań, Poland Key words: legumes, non-nutritive compounds, processing, nutritive quality The consumption of seeds of the Fabaceae family is distributed worldwide mainly due to their high content of proteins, carbohydrates, dietary fi ber and polyunsaturated fatty acids, jointly with vitamins and minerals. However, they contain several non-nutritive compounds (NNCs) that can exert adverse or benefi cial actions upon ingestion depending on their chemical structure, concentration, time of exposure and their interaction with other dietary components. In this review, we present the representative legume NNCs, their chemical nature and their adverse and benefi cial biological ac- tions. Moreover, we summarized updated fi ndings on the effect of different traditional processing, bearing in mind that legumes are mainly consumed in the household milieu, on the concentration of legume NNCs. The results of the in-vivo studies prove that the reduction/elimination of legume NNCs improves nutritional quality and the fate of improvements depends on many parameters such as botanical source, chemical composition, content, type of processing and operational conditions used, among others. Together, this review can provide a comprehensive perspective for further elucidating the roles of plant lectins that may target programmed cell death pathways. This review may, in turn, ultimately help to consumers for whom legumes are part of a vegetarian diet or are consumed as staple food which must take into consideration the improvement of legume nutritive quality by traditional processing. INTRODUCTION -galactosides), tannins, alkaloids, vicine, convicine and sa- ponins, which are heat stable but can be reduced by dehulling, The seeds of the Fabaceae family have been of particu- soaking and cooking, germination and fermentation. A very lar interest to nutritionists as a rich source of protein, fat, interesting fact is that particular genera are characterized carbohydrates, vitamins and microelements, for which they by specifi c NNCs. In this sense, Lupinus contains alkaloids have been recognized as nutritive food. Some examples are and RFOs; Glycine and Pisum are rich in protease inhibitors the seeds of Lupinus luteus which contain about 50% protein, and hemagglutinin; genus Lens contains trypsin inhibitors, the seeds of Lupinus mutabilis and Glycine max which con- condensed tannins and phytates; Phaseolus is character- tain over 20% of fat rich in unsaturated fatty acids, and Lens ized by the fl atulent RFOs, trypsin inhibitors, hemagglutinin culinaris containing 55% of carbohydrates. Unfortunately, and tannins; Cicer contains reasonable levels of trypsin in- the seeds of different species belonging to this botanical family hibitors, hemagglutinin, tannins and saponins; while phytic also contain non-nutritive compounds (NNCs) that decrease acid, saponins and tannins predominate in genus Vigna. nutrient bioavailability affecting legume nutritional quality. Legume NNCs attracted the attention of many research- In addition, some NNCs exert toxic effects in living organisms es during the 80’s and 90’s. However, from the early 2000’s when they are consumed at high doses, which limit in some several studies have shown that many of these compounds cases legume utilization in human nutrition. Some NNCs are can be also considered as pronutrients with positive health secondary plant metabolites, which are accumulated during effects contributing to the prevention of diseases. The bal- seed development in response to biotic and abiotic defense ance between detrimental and benefi cial effects of these mechanisms against insect plagues or adverse environmen- compounds depends on many factors, such as plant origin, tal conditions. These compounds can be classifi ed as NNCs chemical structure, concentration and processing conditions. of protein origin such as trypsin inhibitors and hemaggluti- Although some compounds may exert benefi cial effects they nins that are thermolabile, and NNCs of non-protein origin are still considered by nutritionists as a disadvantageous from like phytic acid, raffi nose family oligosaccharides (RFOs or a nutritional point of view, mainly for people consuming veg- etarian diets or consuming legumes as staple food. Hence, * Corresponding Author: [email protected] (Dr. P. Gulewicz) their total or partial removal is essential to improve the le- © Copyright by Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences © 2014 Author(s). This is an open access articleBrought licensed to you under by | CSICthe Creative - Unidad Commons Coordinacion Attribution-NonCommercial-NoDerivs Bibliotecas License (http://creativecommons.org/licenses/by-nc-nd/3.0/). Authenticated Download Date | 10/9/14 3:33 PM 76 Non-Nutritive Compounds in Fabaceae Family Seeds – a Review gume nutritional quality and their utilization. In this sense, 2009; Vasconcelos et al., 2010]. The levels of PI activity of dif- this review provides updated information on several methods ferent legume species and cultivars are collected in Table 1. of conventional processing including dehulling, germination, Many studies have been conducted to fi nd an effective ap- soaking, cooking, fermentation, extrusion, solvent extraction, proach to remove the PI due to their implications on reducing dry-heating and enzymatic treatments. Other outstanding the protein availability of legumes. Thermal treatments are possibilities as plant breeding, agronomic practices, genetic the most used for the removal of these heat-sensitive com- engineering or even biotechnology application, which have pounds. Vidal-Valverde et al. [1994] showed that cooking been successfully used to reduce NNCs present in crops are of presoaked lentil seeds rich in PI brought about the total not considered here. removal of PI activity. In these studies it was shown that soak- ing was the least effective process. This fi nding agrees with NON-NUTRITIONAL COMPOUNDS the study carried out in pea seeds [Wang et al., 2008a]. Emba- OF PROTEIN ORIGIN by [2010] showed that the dehulling and soaking processes of bitter and sweet lupine seeds for 96 and 24 hours, respec- Protease inhibitors tively, caused a signifi cant increase of trypsin inhibitor activity, Protease inhibitors (PI) are found in most plant organ- whereas cooking led to its inactivation. The cooking and au- isms. They are widely distributed among different botanical toclaving were the most effective processes for the elimination families and are particularly abundant (1–10% of total pro- of PI activity from both lupines [Embaby, 2010]. teins) in storage organs like seeds and tubers [Birk, 2003]. PI can also be extracted by using solvents at alkaline pH, PI have been isolated and characterized from many legume aqueous salt solutions at different pH [Tan et al., 1982] or seeds, e.g. soybean, tepary bean, navy bean, faba bean, cow- with water [Page et al., 2000; Wati et al., 2009]. Each method pea, bambara groundnut and pigeon pea [Benjakul et al., has its own advantages and disadvantages with different tar- 1999; Gupta et al., 2000; Campos et al., 2004; Sammour, get protein components. In this sense, Wati et al. [2009] re- 2005; Guillamon et al., 2008]. ported that extraction with 0.02 mol/L NaOH led to the high- The PI isolated from different species differ by molecu- est recovery of PI from the navy bean and red kidney bean, lar weight, amino acid composition and location of the ac- while water was the best extractant for the adzuki bean. Al- tive site. In most cases, PI occurring in legumes consist of two though cooking is a very simple method for the reduction types, the Bowman-Birk (BBI; 8 kDa) and the Kunitz trypsin of PI activity, this process may lead to the elimination of other family inhibitors (20–24 kDa) [Wati et al., 2009]. The fi rst important compounds like polyphenols. Alonso et al. [1998] one is a small serine proteinase inhibitor containing 71 amino observed that extrusion of pea seeds at 148°C, 25% moisture acids, rich in disulfi de bonds, which has two separate prote- and 100 rpm was the most effective for reduction of con- ase inhibitory sites capable of inhibiting trypsin and chymo- densed tannins, trypsin, chymotrypsin, amylase inhibitors trypsin enzymes [Winiarska-Mieczan, 2007]. Proteins from and hemagglutinating activity reduction without modifi cation the Kunitz family contain 170 to 200 amino acid residues of protein content, which can occur with dehulling, soaking and one or two intra-chain disulfi de bonds. Although the ac- and germination treatments. In addition, PI, chymotrypsin curate mechanism of PI action is not well-known, it is thought inhibitors and hemagglutinating activities were more readily to consist in the formation of non-active complexes