Lipid accumulation in obese Zucker rats is reduced by inclusion of raw kidney bean (Phaseolus vulgaris) in the diet

Health Benefits of Cereal Grain- and Pulse-Derived Proteins

Pulses and whole grains are considered staple foods that provide a significant amount of calories, fibre and protein, making them key food sources in a nutritionally balanced diet. Additionally, pulses and whole grains contain many bioactive compounds such as dietary fibre, resistant starch, phenolic compounds and mono- and polyunsaturated fatty acids that are known to combat chronic disease. Notably, recent research has demonstrated that protein derived from pulse and whole grain sources contains bioactive peptides that also possess disease-fighting properties. Mechanisms of action include inhibition or alteration of enzyme activities, vasodilatation, modulation of lipid metabolism and gut microbiome and oxidative stress reduction. Consumer demand for plant-based proteins has skyrocketed primarily based on the perceived health benefits and lower carbon footprint of consuming foods from plant sources versus animal. Therefore, more research should be invested in discovering the health-promoting effects that pulse and whole grain proteins have to offer.

Common bean (Phaseolus vulgaris L.) α-amylase inhibitors as safe nutraceutical strategy against diabetes and obesity: An update review

Overweight and obesity are constantly increasing, not only in Western countries but also in low‐middle‐income ones. The decrease of both the intake of carbohydrates and their assimilation are among the main dietary strategies to counter these conditions. α‐Amylase, a key enzyme involved in the digestion of carbohydrates, is the target enzyme to reduce the absorption rate of carbohydrates. α‐Amylase inhibitors (α‐AIs) can be found in plants. The common bean, Phaseolus vulgaris is of particular interest due to the presence of protein‐based α‐AIs which, through a protein–protein interaction, reduce the activity of this enzyme. Here we describe the nature of the various types of common bean seed extracts, the type of protein inhibitors they contain, reviewing the recent Literature about their molecular structure and mechanism of action. We also explore the existing evidence (clinical trials conducted on both animals and humans) supporting the potential benefits of this protein inhibitors from P. vulgaris, also highlighting the urgent need of further studies to confirm the clinical efficacy of the commercial products. This work could contribute to summarize the knowledge and application of P. vulgaris extract as a nutraceutical strategy for controlling unwanted weight gains, also highlighting the current limitations.

Dietary Intervention With α-Amylase Inhibitor in White Kidney Beans Added Yogurt Modulated Gut Microbiota to Adjust Blood Glucose in Mice

White kidney beans contain α-amylase inhibitors that can be used in diet for weight reduction. In this study, we investigated the potential of white kidney bean (phaseolus vulgaris L.) extract enriched in α-amylase inhibitor as a food additive in yogurt to regulate blood glucose in hyperglycemic animals. Five groups of C57BL/6J mice were fed for 8 weeks with standard chow diets, high-fat diets (HFD), or high-fat diets with supplement of α-amylase inhibitor in white kidney beans (P. vulgaris extract, PVE), yogurt (Y), and PVE added yogurt (YPVE), respectively. The HFD weakened glucose tolerance and caused insulin resistance in mice, and changed the characteristics of intestinal flora. The intervention of Y, PVE, and YPVE decreased blood glucose, insulin, hyperlipidemia, and inflammatory cytokine levels in mice fed with HFD. Moreover, the YPVE could regulate the components of host intestinal microbiota toward a healthy pattern, significantly increased the metabolic-related flora Corynebacterium, Granulicatella, and Streptococcus, while it decreased Paraprevotella and Allobaculum. Thus, YPVE markedly increased functions of "Amino Acid Metabolism," "Energy Metabolism," "Nucleotide Metabolism," and declined functions of "Glycan Biosynthesis and Metabolism." Consequently, YPVE could be developed as a new functional food because of its beneficial prebiotic properties in the metabolic syndrome.

Regular intake of white kidney beans extract (Phaseolus vulgaris L.) induces weight loss compared to placebo in obese human subjects

Scope

Phaseolus vulgaris L. is rich in alpha-amylase inhibitor and has been used for reducing glycemia and calories absorption through preventing or delaying the digestion of complex carbohydrate. A randomized, double-blinded, placebo-controlled study was conducted on obese volunteers to evaluate the degree of significate weight loss by regular intake Phaseolus vulgaris cultivated from Southwestern region of China.

Method

The volunteers were divided into two groups, homogeneous for age, gender, and body weight. Phaseolus vulgaris extract or placebo was given 2,400 mg per day before each daily meal for 35 consecutive days. Each subject's body weight, fat mass, body mass index, blood biochemical parameters, skinfold fat thickness, and waist/hip circumferences were monitored and analyzed.

Result and conclusion

As a result, the average amount of weight lost by the Phaseolus vulgaris extract group was 2.24 kg (average of 0.448 kg per week), compared with a 0.29 kg weight loss (average of 0.058 kg per week) in placebo group after 35 days. The differences between groups were significant (p < .01). The body mass index decreased by an average of 0.79, and the body fat decreased by 1.53% on average compared to baseline (p < .05). The thickness of subcutaneous fat was significantly reduced at the four measurement points, and the decrease of waist circumference and hip circumference was significant as well. No adverse or side effects were observed during the trial period. The results indicate that Phaseolus vulgaris extract can significantly induce weight loss in a short time period.

Canavalia ensiformis-derived lectin inhibits biofilm formation of enterohemorrhagic Escherichia coli and Listeria monocytogenes

AIM

A lectin Concanavalin A (ConA) derived from Canavalia ensiformis (jack bean) exhibits high-binding affinity to carbohydrates on bacterial cell surfaces. The objective of this study was to inhibit the biofilm formation of the foodborne pathogens enterohemorrhagic Escherichia coli and Listeria monocytogenes using ConA prepared by a membrane-based extraction method.

METHODS AND RESULTS

ConA was extracted using a simple and inexpensive membrane method instead of a chromatography approach. The extracted ConA was effective in inhibiting biofilms of E. coli by 30-fold and L. monocytogenes by 140-fold. In addition, ConA decreased the swimming motility of enterohemorrhagic E. coli EDL933 (EHEC) by 37%, resulting in low biofilm formation, as ConA binding to the bacterial cell surfaces might cause a reduced capability to adhere due to low cellular motility. We confirmed that the extracted ConA contains active components at less than 10 kDa as well as ConA multimers (>30 kDa) that repress EHEC biofilms. Additionally, noncell-based mannose reduced the activity of ConA in inhibiting biofilms.

CONCLUSIONS

ConA extracted using the membrane-based method is active in inhibiting the biofilm formation by E. coli and L. monocytogenes via the mannose-binding affinity of ConA.

SIGNIFICANCE AND IMPACT OF THE STUDY

ConA can be used as a promising anti-adherent and antibiofilm agent in inhibiting biofilm formation by enterohemorrhagic E. coli and L. monocytogenes. The membrane-based extraction approach may be applied for the economic production of biologically active lectins.

Phaseolus vulgaris lectins: A systematic review of characteristics and health implications

Legume lectins are carbohydrate-binding proteins of non-immune origin. Significant amounts of lectins have been found in Phaseolus vulgaris beans as far back as in the last century; however, many questions about their potential biological roles still remain obscure. Studies have shown that lectins are anti-nutritional factors that can cause intestinal disorders. Owing to their ability to act as toxic allergens and hemagglutinins, the Phaseolus vulgaris lectins are of grave concern for human health and safety. Nonetheless, their potential beneficial health effects, such as anti-cancer, anti-human immunodeficiency virus (anti-HIV), anti-microbial infection, preventing mucosal atrophy, reducing type 2 diabetes and obesity, promoting nutrients absorption and targeting drugs, are of immense interest. The significance of Phaseolus vulgaris lectins in biological researches and the potential biomedical applications have placed tremendous emphasis on the development of purification strategies to obtain the protein in pure and stable forms. These purification strategies entail considerations such as effects of proteolysis, heating, gamma radiation, and high-hydrostatic-pressure that can have crucial outcomes in either eliminating or improving bioactivities of the lectins. Thus, up-to-date research findings of Phaseolus vulgaris lectins on different aspects such as anti-nutritional and health impacts, purification strategies and novel processing trends, are systematically reviewed.

A Phaseolus vulgaris Extract Reduces Cue-Induced Reinstatement of Chocolate Seeking in Rats

Previous evidence has suggested that treatment with a standardized dry extract of Phaseolus vulgaris reduced intake and operant self-administration of highly palatable foods and fluids in rats and mice. The present study was designed to assess whether such extract was also effective in reducing seeking behavior for a highly hedonic chocolate-flavored beverage, using a "reinstatement" procedure adopted from the drug addiction research field and modeling relapse behavior. Rats were initially trained to lever-respond for the chocolate-flavored beverage under the Fixed Ratio (FR) 10 schedule of reinforcement. Subsequently, rats were exposed to an extinction responding phase, during which lever-responding - being unreinforced - diminished progressively up to extinction. Lever-responding was then powerfully reinstated by the non-contingent presentation of a complex of gustatory, olfactory, auditory, and visual stimuli previously associated to the availability of the chocolate-flavored beverage. Acute, intragastric administration of P. vulgaris dry extract (100 and 500 mg/kg) reduced lever-responding by 40-45%, in comparison to vehicle condition. These results indicate the ability of P. vulgaris dry extract to reduce seeking behavior for a highly palatable nourishment in an experimental model of relapse into disordered eating of palatable foods. The unavailability of the chocolate-flavored beverage in the reinstatement session tends to exclude that the observed effect of the P. vulgaris dry extract was secondary to any inhibition of carbohydrate metabolism; conversely, it is the likely consequence on a central action on the rewarding and hedonic properties of food.

Plants used in the traditional medicine of Mesoamerica (Mexico and Central America) and the Caribbean for the treatment of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Obesity is a worldwide medical concern. New ethnobotanical information regarding the antiobesity effect of medicinal plants has been obtained in the last 30 years in response to socio-demographic changes and high-fat diets became common.

AIM OF THE STUDY

This review provides a summary of medicinal plants used in Mexico, Central America and the Caribbean for the empirical treatment of obesity in terms of ethnobotany, toxicity, pharmacology, conservation status, trade and chemistry.

MATERIALS AND METHODS

Bibliographic investigation was performed by analyzing recognized books, undergraduate and postgraduate theses and peer-reviewed scientific articles, consulting worldwide accepted scientific databases from the last four decades. Medicinal plants used for the treatment of obesity were classified in two categories: (1) plants with pharmacological evidence and (2) plants without pharmacological evidence.

RESULTS

A total of 139 plant species, belonging to 61 families, native to Mexico, Central America and the Caribbean that are used for the empirical treatment of obesity were recorded. From these plants, 33 were investigated in scientific studies, and 106 plants lacked scientific investigation. Medicinal plants were experimentally studied in vitro (21 plants) and in vivo (16 plants). A total of 4 compounds isolated from medicinal plants used for the empirical treatment of obesity have been tested in vitro (2 compounds) and in vivo (4 compounds) studies. No clinical trials on obese subjects (BMI>30 kg/m(2)) have been performed using the medicinal plants cited in this review. There are no herbal-based products approved in Mexico for the treatment of obesity.

CONCLUSIONS

There are a limited number of scientific studies published on medicinal plants from Mexico, Central America and the Caribbean used for the treatment of obesity. This review highlights the need to perform pharmacological, phytochemical, toxicological and ethnobotanical studies with medicinal flora to obtain new antiobesity agents.

Effect of White Kidney Beans (Phaseolus vulgaris L. var. Beldia) on Small Intestine Morphology and Function in Wistar Rats

The chronic ingestion of raw or undercooked kidney beans (Phaseolus vulgaris L.) causes functional and morphological derangement in various tissues. The major objectives of this study were to investigate the gavage effects of a raw Beldia bean variety that is widely consumed in Tunisia, on the small intestine morphology and jejunal absorption of water, electrolytes, and glucose in Wistar rats. Twenty young male rats were randomly divided into two groups of 10 rats. The first group served as the control and was gavaged with 300 mg of a rodent pellet flour suspension (RPFS), whereas the second experimental group was challenged with 300 mg of a Beldia bean flour suspension (BBFS) for 10 days. Histological studies were performed using light and electron microcopy. The intestinal transport of water, sodium, potassium, and glucose was studied by perfusing the jejunal loops of the small bowels in vivo. The feeding experiments indicated that BBFS did not affect weight gain. Histomorphometric analyses showed that the villus heights, crypt depths, and crypt/villus ratios in the jejunum and ileum were greater in the BBFS-fed rats than controls. Electron microscopy studies demonstrated that the rats exposed to RPFS exhibited intact intestinal tracts; however, the BBFS-treated rats demonstrated intestinal alterations characterized by abnormal microvillus architectures, with short and dense or long and slender features, in addition to the sparse presence of vesicles near the brush border membrane. BBFS administration did not significantly affect glucose absorption. However, significant decreases were observed in water and electrolyte absorption compared with the uptake of the controls. In conclusion, raw Beldia beans distorted jejunum morphology and disturbed hydroelectrolytic flux.

Whole grains and pulses: a comparison of the nutritional and health benefits

Nutrition plays an important role in the prevention and management of disease. Whole grain cereals contain a host of nutrients and bioactive substances that have health-promoting effects. Epidemiological evidence shows a consistent inverse association between whole grain intake and the risk of chronic disease. Despite a concerted effort by scientists, educators, and policy makers to promote the consumption of whole grains, it remains dismally short of the recommended intakes. Pulses (dried beans and peas) differ from whole grains in their structural and physicochemical properties and have varying amounts of fiber, resistant starch, vitamins, minerals, and other bioactive components; nevertheless, these food groups complement each other. Observational as well as intervention trials show that pulse consumption has beneficial effects on the prevention and management of chronic disease. The nutritional and phytochemical components of pulses coupled with those of whole grains suggest a potential synergistic effect that could provide significant health benefits.

A review on botanical species and chemical compounds with appetite suppressing properties for body weight control

As obesity has reached epidemic proportions, the management of this global disease is of clinical importance. The availability and popularity of natural dietary supplements for the treatment of obesity has risen dramatically in recent years. The purpose of this paper was to review the effect of commonly available over the counter plant-derived supplements used to suppress appetite for obesity control and management. The data were obtained from the electronic databases PubMed, SpringerLink, Google Scholar, ScienceDirect, and MEDLINE with full text (via EBSCOHost) and the databases were accessed during late 2012 - early January 2013. The botanical species discussed in this review include Camellia sinensis, Caralluma fimbriata, Citrus aurantium, Coleus forskohlii, Garcinia cambogia and Phaseolus vulgaris. This review found that many botanical species including crude extracts and isolated compounds from plants have been shown to provide potentially promising therapeutic effects including appetite control and weight loss. However, many of these crude extracts and compounds need to be further investigated to define the magnitude of the effects, optimal dosage, mechanisms of action, long term safety, and potential side effects.

Bioactivity of antioxidants in extruded products prepared from purple potato and dry pea flours

Measuring antioxidant activity using a biologically relevant assay adds important evidence to aid in understanding the role of phytochemicals based on data from in vivo and chemical assays of extrusion processed purple potato and pea flours. A cellular antioxidant activity assay could provide biologically relevant information on bioactive compounds in raw as well as processed food products. The objective of this study was to investigate the complete phytochemical profiles, antioxidant activity, cellular antioxidant activity, and their contribution to bioactivity in purple potato flour, dry pea flour, raw formulations, and extrusion cooked products prepared with the above ingredients. The free fraction of extracts contributed 68, 64, and 88% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in purple potato flour (PPF). Similarly, extracts in the free fraction contributed 87, 86, and 64% to total phenolics, total antioxidant activity (ORAC value), and total flavonoids, respectively, in dry pea flour (DPF). The amount of total phenolics and total flavonoids in purple potato flour and the antioxidant activity of PPF and DPF were comparable to published data. However, a higher amount in the total flavonoids and lower in the total phenolics of DPF were observed. Caffeic, p-coumaric, and ferulic acids were mostly observed in the bound extracts of raw formulations as in the extrudates, whereas chlorogenic acid was predominant in the free extracts. The extruded products had significantly higher (p < 0.05) content of total phenolics, ORAC antioxidant activity, and flavonoids, compared to the raw formulations. Extrusion processing increased the cellular antioxidant activity of the extrudates prepared from 35:65 and 50:50 PPF/DPF (w/w) of ingredients compared with control raw formulations in a dose-dependent manner. Increase of PPF significantly increased (p < 0.05) the cellular antioxidant activity of 35-50% PPF formulations.

Effect of extrusion on the antioxidant capacity and color attributes of expanded extrudates prepared from purple potato and yellow pea flour mixes

Foods with antioxidant capacity provide protection against cardio-vascular, certain forms of cancers, and Alzheimer's diseases caused by oxidative damages and contribute health benefits. The effect of extrusion cooking on the antioxidant capacity and color attributes of extruded products prepared from 3 selected formulations of purple potato and yellow pea flours using a co-rotating twin screw extruder were studied. Expansion ratios of the extruded products varied from 3.93 to 4.75. The total antioxidant capacities (TAC) of the extruded products, using DPPH assay, were 3769 to 4116 μg trolox equivalent/g dry weight sample and not significantly different (P > 0.05) from their respective raw formulations. The total phenolic contents (TP) of the extruded products varied from 2088 to 3766 μg of gallic acid equivalent/g dry weight sample and retained 73% to 83% of the TP from the raw formulations after extrusion. The total anthocyanins contents (TA) in the extrudates were 0.116 to 0.228 mg of malvidin-3-glucosides/g dry weight sample. Compared with their raw formulations, significant losses (60% to 70%) of the TA in the extruded products occurred due to extrusion cooking. Browning indices and color attributes such as brightness, chroma, and hue angle agreed with degradation of anthocyanins in the extruded products. However, extrusion cooking retained antioxidant capacities of the raw formulations in the extruded products either in their natural forms or degraded products with radical scavenging activity. This study demonstrated the potential for the production of puffed extruded food products with the improved antioxidant content from colored potatoes and pulse formulations.

Multiple cycles of repeated treatments with a Phaseolus vulgaris dry extract reduce food intake and body weight in obese rats

Previous lines of experimental evidence have suggested that Phaseolus vulgaris extracts reduce food intake, body weight, lipid accumulation, hedonic properties of food, carbohydrate absorption and metabolism, and glycaemia in rats. The present study was designed to assess the effect of multiple cycles of repeated treatments with a standardised P. vulgaris dry extract on daily food intake and body weight in genetically obese Zucker fa/fa rats (Expt 1). Additionally, the study tested the effect of acute treatment with P. vulgaris dry extract on postprandial glycaemia in Zucker fa/fa rats (Expt 2). In Expt 1, P. vulgaris dry extract was administered daily, at doses of 50 and 500 mg/kg, in three 5 d treatment periods followed by three 20 d off-treatment periods. Administration of P. vulgaris dry extract resulted in dose-dependent decreases in daily food intake and body weight in each treatment phase. Reductions in food intake were of comparable magnitude in each treatment phase. In Expt 2, food-deprived rats were acutely treated with 50 and 500 mg P. vulgaris dry extract per kg immediately before access to a fixed amount of a starch-enriched chow. Treatment with P. vulgaris dry extract resulted in a dose-dependent suppression of glycaemia. These results extend previous data on the anorectic and hypoglycaemic effects of the P. vulgaris dry extract to a validated animal model of obesity. Together with data published previously in the literature, these results strengthen the hypothesis that potentially effective, novel pharmacotherapies for obesity and related disorders may originate from extracts and derivatives of P. vulgaris.

Potential efficacy of preparations derived from Phaseolus vulgaris in the control of appetite, energy intake, and carbohydrate metabolism

Preclinical data on extracts of and preparations derived from beans of Phaseolus vulgaris are reviewed as potential remedies for use in controlling food consumption, body weight, lipid accumulation, and glycemia. A growing body of evidence suggests that acute and chronic administration of P. vulgaris derivatives reduces food intake (including highly palatable foods), body weight, lipid deposit, and glycemia in rats exposed to multiple experimental procedures. Two possible lectin-mediated mechanisms of action have been proposed: (a) inhibition of α-amylase, resulting in a reduced carbohydrate metabolism and absorption; (b) phytohemoagglutinin-induced modulation of the activity of cholecystokinin and glucagon-like peptides, resulting in a reduced appetite. Preliminary clinical data, as well as reports focusing on the use of several traditional medicines, apparently extend these findings to humans. Should these initial clinical data be confirmed by future surveys, P. vulgaris derivatives might constitute novel remedies for the treatment of obesity and metabolic syndrome. Future studies are also expected to identify active structures leading to the development of new pharmaceutical agents.

A systematic review of the efficacy and safety of herbal medicines used in the treatment of obesity

This review focuses on the efficacy and safety of effective herbal medicines in the management of obesity in humans and animals. PubMed, Scopus, Google Scholar, Web of Science, and IranMedex databases were searched up to December 30, 2008. The search terms were "obesity" and ("herbal medicine" or "plant", "plant medicinal" or "medicine traditional") without narrowing or limiting search elements. All of the human and animal studies on the effects of herbs with the key outcome of change in anthropometric measures such as body weight and waist-hip circumference, body fat, amount of food intake, and appetite were included. In vitro studies, reviews, and letters to editors were excluded. Of the publications identified in the initial database, 915 results were identified and reviewed, and a total of 77 studies were included (19 human and 58 animal studies). Studies with Cissus quadrangularis (CQ), Sambucus nigra, Asparagus officinalis, Garcinia atroviridis, ephedra and caffeine, Slimax (extract of several plants including Zingiber officinale and Bofutsushosan) showed a significant decrease in body weight. In 41 animal studies, significant weight loss or inhibition of weight gain was found. No significant adverse effects or mortality were observed except in studies with supplements containing ephedra, caffeine and Bofutsushosan. In conclusion, compounds containing ephedra, CQ, ginseng, bitter melon, and zingiber were found to be effective in the management of obesity. Attention to these natural compounds would open a new approach for novel therapeutic and more effective agents.

The nutraceutical role of thePhaseolus vulgarisα-amylase inhibitor

The present review assesses the potential of thePhaseolus vulgarisα-amylase inhibitor isoform 1 (α-AI1) starch blockers as a widely used remedy against obesity and diabetes. Consumption of the α-amylase inhibitor causes marginal intraluminal α-amylase activity facilitated by the inhibitor's appropriate structural, physico-chemical and functional properties. As a result there is decreased postprandial plasma hyperglycaemia and insulin levels, increased resistance of starch to digestion and increased activity of colorectal bacteria. The efficacy and safety of the amylase inhibitor extracts, however, depend on the processing and extraction techniques used. The extracts are potential ingredients in foods for increased carbohydrate tolerance in diabetics, decreased energy intake for reducing obesity and for increased resistant starch. Research developments in the distribution and biosynthesis of the α-amylase inhibitor, relevant physico-chemical properties, the molecular starch-blocking mechanism, anti-obesity and anti-diabetes effects, safety of extracts and the need for research into their potential anti-colorectal cancer effect are discussed.

Consumption of pork-liver protein hydrolysate reduces body fat in Otsuka Long-Evans Tokushima Fatty rats by suppressing hepatic lipogenesis

This study was performed to examine the effect of consumption of pork-liver protein hydrolysate (PLH) on body fat accumulation in Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a non-insulin-dependent diabetes mellitus model and in Long-Evans Tokushima Otsuka (LETO) rats as a control. Male 20-week-old OLETF and LETO rats were pair-fed either PLH or casein containing diet for 14 weeks. In the OLETF rats, dietary PLH significantly reduced the growth and weight of fat pad including perirenal and epididymal adipose tissues. Consumption of PLH markedly suppressed hepatic activities of lipogenesis enzymes such as glucose-6-phosphate dehydrogenase and fatty acid synthase and slightly elevated fecal excretion of total fat. In the LETO rats, growth and adipose tissue weight were unaffected by dietary treatment. The results suggest that PLH is a novel ingredient suppressing body fat in genetically obese rats by reducing lipogenesis.

Non-nutrient bioactive substances of pulses

Pulses supply many bioactive substances found in minor amounts in food, but which may have significant metabolic and/or physiological effects. These compounds have long been classified as antinutritional factors, but many studies have reconsidered their impact on health. Some could play a role in the prevention of the major diseases of affluent societies. As these compounds can be beneficial or adverse, depending on conditions, an assessment of their various physiological effects is necessary to determine whether they should be preserved or eliminated in each main nutritional situation.

Nutritional significance of lectins and enzyme inhibitors from legumes

Legumes have natural components, such as lectins, amylase, and trypsin inhibitors, that may adversely affect their nutritional properties. Much information has already been obtained on their antinutritional significance and how to inactivate them by proper processing. Chronic ingestion of residual levels is unlikely to pose risks to human health. On the other hand, the ability of these molecules to inhibit some enzymes such as trypsin, chymotrypsin, disaccharidases, and alpha-amylases, to selectively bind to glycoconjugates, and to enter the circulatory system may be a useful tool in nutrition and pharmacology. Trypsin inhibitors have also been studied as cancer risk reducing factors. These components seem to act as plant defense substances. However, increased contents may represent an impairment of the nutritional quality of legumes because these glycoproteins and the sulfur-rich protease inhibitors have been shown to be poorly digested and to participate in chemical reactions during processing reducing protein digestibility, a still unsolved question.

Muscle and liver protein metabolism in rats fed raw or heat-treated pea seeds

Raw or extruded pea (Pisum sativum, cv. Ballet) diets with or without supplementary amino acids were fed for 15 days to young growing rats and the effects on tissue weights, liver and muscle protein metabolism and hormone levels monitored. Body weight gain, liver and gastrocnemius muscle weights and protein contents were reduced and some key hormones altered when rats were fed unsupplemented raw pea diets. This appeared to be a result of amino acid deficiencies in the diet, the action of antinutritional factors and the refractory nature of the reserve proteins and other seed components. However, this did not in itself improve the nutritional performance of the rats due to the overriding effects of the amino acid deficiencies in the pea diets. After supplementation, extruded peas supported much higher rates of growth and skeletal muscle deposition than did supplemented raw peas. Despite this, the weight gains remained less than achieved on a high quality control diet. Protein synthesis and degradation rates in skeletal muscles and total protein contents were similar to control values. The lower growth rate did not appear to be due to impaired deposition of skeletal muscle. Deposition of other body components, possibly lipids, may have been lowered by supplemented extruded pea diets. Liver protein levels were reduced in rats fed supplemented raw peas and blood corticosterone was elevated. In conclusion, extrusion treatment of peas in combination with amino acid supplementation appeared to abolish the negative effects of peas on skeletal muscle deposition.

Dietary soya beans and kidney beans stimulate secretion of cholecystokinin and pancreatic digestive enzymes in 400-day-old Hooded-Lister rats but only soya beans induce growth of the pancreas

The effects of age on cholecystokinin (CCK) release, pancreatic enzyme secretion, and growth of the pancreas mediated by dietary kidney beans or soya beans were evaluated in trials with 30-, 90-, 250-, and 400-day-old rats. Soya beans increased blood CCK and caused hypersecretion of digestive enzymes and rapid pancreatic growth in all rats. Kidney beans also elevated circulating CCK and stimulated enzyme secretion. However, with 90-, 250-, and 400-day-old rats, the secretory responses were attenuated. Furthermore, kidney beans did not induce pancreatic growth in 250- and 400-day-old rats.