Proanthocyanidins (syn condensed tannins) are complex flavonoid polymers naturally present in cereals, legume seeds and particularly abundant in some fruits and fruit juices. They share some common structural features—phenolic nature and high molecular weight—with phenolic polymers found in black tea and red wine (called here tannin-like compounds). The polymeric nature of proanthocyanidins makes their analysis and estimation in food difficult. For this reason, little is known about their consumption, although they likely contribute a large part of the daily polyphenol intake. They also share common physicochemical properties: they form stable complexes with metal ions and with proteins and are, like other polyphenols, good reducing agents. Many of their biological effects of nutritional interest derive from these properties. As metal ion chelators, they influence the bioavailability of several minerals. The nutritional significance of the non-specific complexation of proteins is less clear. As reducing agents, they may participate in the prevention of cancers, both of the digestive tract and inner organs. They may also protect LDLs against oxidation and inhibit platelet aggregation and therefore prevent cardiovascular diseases. In vitro, animal and human studies on the prevention of these chronic diseases are reviewed with particular attention to wine and tea polyphenols. The lack of data on their bioavailability and the paucity of human studies are emphasised.

© 2000 Society of Chemical Industry

Proanthocyanidins and tannin-like compounds – nature, occurrence, dietary intake and effects on nutrition and health

Dietary fibre is that part of plant material in the diet which is resistant to enzymatic digestion which includes cellulose, noncellulosic polysaccharides such as hemicellulose, pectic substances, gums, mucilages and a non-carbohydrate component lignin. The diets rich in fibre such as cereals, nuts, fruits and vegetables have a positive effect on health since their consumption has been related to decreased incidence of several diseases. Dietary fibre can be used in various functional foods like bakery, drinks, beverages and meat products. Influence of different processing treatments (like extrusion-cooking, canning, grinding, boiling, frying) alters the physico- chemical properties of dietary fibre and improves their functionality. Dietary fibre can be determined by different methods, mainly by: enzymic gravimetric and enzymic—chemical methods. This paper presents the recent developments in the extraction, applications and functions of dietary fibre in different food products.

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Dietary fibre in foods: a review

The objective of this study was to investigate how 6 commonly used solvent systems affected the yields of phenolic substances and the antioxidant capacity of extracts from 8 major classes of food legumes. Several antioxidant-related phytochemical compositions, namely, total phenolic content (TPC), total flavonoids content (TFC), and condensed tannins content (CTC), were investigated. In addition, antioxidant activities were tested using 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging, ferric-reducing antioxidant power (FRAP), and the oxygen radical absorbance capacity (ORAC). The results showed that the 50% acetone extracts exhibited the highest TPC for yellow pea, green pea, chickpea, and yellow soybean. Acidic 70% acetone (+0.5% acetic acid) extracts exhibited the highest TPC, TFC, and FRAP values for black bean, lentil, black soybean, and red kidney bean. The 80% acetone extracts exhibited the highest TFC, CTC, and DPPH-free radical scavenging activity for yellow pea, green pea, chickpea, and yellow soybean. The 70% ethanol extracts exhibited the greatest ORAC value for all selected legumes. These results indicated that solvents with different polarity had significant effects on total phenolic contents, extracted components, and antioxidant activities. High correlations between phenolic compositions and antioxidant activities of legume extracts were observed. The information is of interest to the nutraceutical food/ingredient industries since legumes are a rich source of antioxidants.

A Comparative Study on Phenolic Profiles and Antioxidant Activities of Legumes as Affected by Extraction Solvents

Sorghum phytochemicals and their potential impact on human health.

Chickpea (Cicer arietinum L.) is an important pulse crop grown and consumed all over the world, especially in the Afro-Asian countries. It is a good source of carbohydrates and protein, and protein quality is considered to be better than other pulses. Chickpea has significant amounts of all the essential amino acids except sulphur-containing amino acids, which can be complemented by adding cereals to the daily diet. Starch is the major storage carbohydrate followed by dietary fibre, oligosaccharides and simple sugars such as glucose and sucrose. Although lipids are present in low amounts, chickpea is rich in nutritionally important unsaturated fatty acids such as linoleic and oleic acids. β-Sitosterol, campesterol and stigmasterol are important sterols present in chickpea oil. Ca, Mg, P and, especially, K are also present in chickpea seeds. Chickpea is a good source of important vitamins such as riboflavin, niacin, thiamin, folate and the vitamin A precursor β-carotene. As with other pulses, chickpea seeds also contain anti-nutritional factors which can be reduced or eliminated by different cooking techniques. Chickpea has several potential health benefits, and, in combination with other pulses and cereals, it could have beneficial effects on some of the important human diseases such as CVD, type 2 diabetes, digestive diseases and some cancers. Overall, chickpea is an important pulse crop with a diverse array of potential nutritional and health benefits.

http://exploreit.icrisat.org/sites/default/files/uploads/1378788243_BJN_Chickpea_Paper_Gaur_etal._2012_Review.pdf

Nutritional quality and health benefits of chickpea (Cicer arietinum L.): a review.

The effect of different conditions of germination at a semi-pilot scale on the content of available soluble sugars, alpha-galactosides, vitamins B1 and B2, and inositol phosphates of beans, lentils and peas have been studied. Results obtained indicated that germination modified the nutritional composition of legumes depending on the type of legume and germination conditions. The storage compounds present in dry seeds (alpha-galactosides and higher forms of inositol phosphates) decreased because they were hydrolysed to glucose, fructose, IP4 and IP3, compounds that can serve as a source of energy for the new plant. Vitamin B2 suffered an important increase after germination whereas vitamin B1 did not change significantly. To achieve legume flours with enhanced nutritive value, 6 days of germination in the presence of light for beans and lentils, and in darkness for peas can be suggested.

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New functional legume foods by germination: effect on the nutritive value of beans, lentils and peas

Effect of germination and fermentation on the antioxidant vitamin content and antioxidant capacity of Lupinus albus L. var. Multolupa

Changes in the trypsin inhibitor activity and in the phytic acid, tannin, and catechin content of lentils (Lens culinaris var. Vulgaris) were investigated after soaking in distilled water, citric acid, and sodium bicarbonate solutions. The effect of cooking, after the seeds were presoaked in the above-mentioned solutions and both the soaking and cooking solutions were discarded, was also studied. Finally, two varieties of lentils (L. culinaris var. Vulgaris and Variabilis) were germinated for 6 days, and the effect on the trypsin inhibitor activity and the phytic acid, tannin, and catechin contents was also measured. Soaking did not modify the trypsin inhibitor activity, decreased the phytic acid content, and increased the tannin and catechin contents. Cooking the presoaked seed brought about the total removal of trypsin inhibitor activity, a reduction of the phytic acid level, and an increase of the content of tannins and catechins. The trypsin inhibitor activity and the phytic acid content showed a large decrease after 6 days of germination, while amounts of tannins and catechins in the two lentil varieties studied increased. Cooking and germination seem to be good procedures to improve the quality of lentil flour from the nutritional point of view, despite the fact that a large variation on the effects of processing, related to the different legume varieties, has been observed.

Effect of processing on some antinutritional factors of lentils

https://digital.csic.es/bitstream/10261/64995/6/antioxidant_antihypertensive_Torino.pdf

Concepción Vidal-Valverde

Papers

New functional legume foods by germination: effect on the nutritive value of beans, lentils and peas

Effect of germination and fermentation on the antioxidant vitamin content and antioxidant capacity of Lupinus albus L. var. Multolupa

Effect of processing on some antinutritional factors of lentils

Antioxidant and antihypertensive properties of liquid and solid state fermented lentils.

Germinated Cajanus cajan seeds as ingredients in pasta products: Chemical, biological and sensory evaluation