In vitro protein digestibility and mineral availability of green beans (Phaseolus vulgarisL) as influenced by variety and pod size

Three varieties of green beans (Cleo, Strike and Sentry) were harvested and sorted into four fractions according to pod size (diameter <7 mm; 7–8·5 mm; 8·6–10 mm and >10 mm). Ash content and dietary fibre increased significantly as pod size increased mainly in Cleo and Strike beans. Strike showed the highest fibre content (378·0 g kg⁻¹) but the lowest carbohydrate (364·6 g kg⁻¹) and ash (68·4 g kg⁻¹) values. Mean values for Fe and Mg content were higher in Cleo beans (70·9 and 27·1 mg kg⁻¹, respectively), Zn, Cu and Mg were higher in Strike beans (48·7 mg kg⁻¹, 22·4 mg kg⁻¹ and 3·15 g kg⁻¹, respectively) while Na and Ca values were maximum in Sentry (459·1 mg kg⁻¹ and 7·11 g kg⁻¹, respectively). Trypsin inhibitor was negatively related to in vitro protein digestibility but no relationship was found between this last parameter and phytic acid content. This antinutrient, together with dietary fibre, and a negative influence on in vitro mineral dialysability of green beans. © 1998 SCI     

Lipase from Vicia faba minor

Lipase was partially purified from small faba beans by ethanol precipitation and Sephadex gel filtration and characterised by disc gel electrophoresis, isoelectric focusing and molecular weight determination in the presence of sodium dodecyl sulphate. Kinetic studies demonstrated that the properties of the enzyme conformed generally to those of lipases from other sources. The isoelectric point was pH 4·8, and electrophoresis at pH 9·3 revealed one lipase band in the R_f0·25–0·31 region. The molecular weight was 210,000 ± 20,000. The possible importance of lipase is discussed with respect to the degradation of small faba bean lipids and to chemical changes occurring during storage of processed faba beans.     

Oligosaccharides, Antinutritional Factors, and Protein Digestibility of Dry Beans as Affected by Processing

Dry beans (Phaseolus vulgaris) were subjected to soaking, cooking or a combination of both prior to fermentation, and then assessed for oligosaccharides, antinutritional factors and in-vitro protein digestibility. Results showed an important decrease in raffinose oligosaccharides and antinutritional factors. However, an increase of trypsin inhibitor and tannin contents occurred respectively in cooked or soaked-cooked fermented beans and in raw or soaked fermented beans. Appreciable improvement in in-vitro protein digestibility was only observed in cooked or soaked-cooked beans. After fermentation, the largest decreases were observed in soaked-cooked beans (92.75%) for raffinose, in cooked beans (31.57%) for phytic acid, in soaked beans (90.86%) for stachyose, and in raw beans for trypsin inhibitor (38.77%). The highest increase due to fermentation was observed in raw beans for in-vitro protein digestibility (1.73%).     

Effect of Storage Conditions and Chemical Treatments on Firmness, in Vitro Protein Digestibility, Condensed Tannins, Phytic Acid and Divalent Cations of Cooked Black Beans (Phaseolus vulgaris)

Black beans stored at 30° or 40°C and 80% relative humidity showed marked increases in firmness and decreases in in vitro digestibility of proteins. Changes in these properties were small when beans were stored at 5°C and 50% relative humidity. The adverse effects of poor storage conditions could be practically eliminated by soaking beans in salt solutions instead of water. The changes in firmness and digestibility were accompanied by changes in the detectable concentrations of tannins and phytates. Protein digestibility appears to be reduced by interactions between protein and tannins, especially high molecular weight tannins. Concentration of these tannins is affected by poly-phenol oxidase activity. Firmness increased and protein digestibility decreased as the phytic acid content decreased.     

The impact of processing on phytic acid,in vitro soluble iron and Phy/Fe molar ratio of faba bean (Vicia faba L.)

BACKGROUND: Faba bean is one of the important legumes in Asian countries. It is also a major source of micronutrients in many rural areas. Unfortunately, the bioavailability of iron from faba bean is low because it is present as an insoluble complex with food components such as phytic acid. The influence of soaking, germination and fermentation with the expectation of increasing the bioavailability of iron was investigated. RESULTS: Fermentation treatments were most effective in decreasing phytic acid (48–84%), followed by soaking at 10 °C after preheating (36–51%). Steeping faba beans for 24 h at 25 °C had the least effect on the removal of phytic acid (9–24%). With increased germination time at 30 °C, phytic acid progressively decreased from 9 to 69%. Most wet processing procedures, except soaking after wet preheating, caused losses of dry matter and iron (8–15%). In vitro iron solubility, as a percentage of total iron in soaked faba bean after dry preheating, was significantly higher than in raw faba bean (P < 0.05). Fermentation and germination did not have significant effects on the solubility of iron. CONCLUSION: The expected improvement of iron bioavailability levels due to lower phytic acid was not confirmed by increasing levels of in vitro soluble iron. Soaking, germination and fermentation can decrease phytic acid in faba bean. However, results from in vitro solubility measurement of iron showed little improvement of iron bioavailability in fermented and germinated faba beans over untreated raw faba beans (P < 0.05). It seems that componets of dietary fibre other than phytic acid are more important in binding iron. Probably, a complex association between dietary fibre and iron is the reason for the poor bioavailability of iron in faba bean. Copyright © 2009 Society of Chemical Industry     

Nutrient contents,rumen protein degradability and antinutritional factors in some colour- and white-flowering cultivars of Vicia faba beans

Six colour-flowering (Scirocco, Alfred, Carola, Condor, Tina and Herz Freya) and six white-flowering (Caspar, Albatros, Gloria, Tyrol, Vasco and Cresta) cultivars of Vicia faba were studied. The crude protein contents of colour- and white-flowering cultivars were 267±13·6 and 283±18·8 g kg⁻¹, respectively, which did not differ significantly at P<0·05. The levels of lipids, crude fibre, starch and ash varied from 14 to 22 g kg⁻¹, 88 to 143 g kg⁻¹, 407 to 485 g kg⁻¹ and 32 to 42 g kg⁻¹, respectively. The calculated organic matter digestibility (OMD) and metabolisable energy (ME) of the white-flowering cultivars were significantly higher (P<0·001) than those of the colour-flowering cultivars (OMD: 889·1±26·6 g kg⁻¹ vs 797·5±17·1 g kg⁻¹; ME: 13·97±0·49 vs 12·30±0·34 MJ kg⁻¹). In all cultivars, sulphur amino acids were lower than adequate concentration when compared with recommended amino acid pattern of FAO/WHO/UNO reference protein for a 2–5-year-old child. The in vitro rumen nitrogen degradability of colour-flowering cultivars was significantly lower (P<0·01) compared to that of white-flowering cultivars (71·4±9·3% vs 88·0±11·1%). Amongst colour-flowering varieties, the contents of total phenols (TP), tannins (T) and condensed tannins (CT) were highest in Alfred (28·3, 21·0 and 35·4 g kg⁻¹, respectively). The contents of TP and T were similar (about 15 and 10 g kg⁻¹, respectively) in Carola, Tina and Herz Freya, and the CT were in the order: Condor>Herz Freya>Carola. The CT were not detected in white-flowering varieties, T were virtually absent and TP were extremely low (4·0–4·9 g kg⁻¹). The activities of other antinutritional factors (white- and colour-flowering cultivars, respectively: trypsin inhibitor activity 3·05±0·34 and 1·85±0·09 mg trypsin inhibited g⁻¹; lectin 27·2±9·4 and 27·1±5·1 mg ml⁻¹ assay medium producing haemagglutination; phytate 15·0±2·7 and 16·6±2·3 g kg⁻¹) were very low. A strong negative correlation (r=-0·92, P<0·001) between tannins and in vitro rumen protein degradability was observed which suggested that tannins have adverse effect on protein degradability. Similarly negative correlations between tannin levels and metabolisable energy (r=-0·89; P<0·001) and organic matter digestibility (r=-0·89; P<0·001) were observed. The correlation coefficient between trypsin inhibitor activity and tannins was negative and highly significant (r=-0·88, P<0·001), whereas between tannins and saponins it was significantly positive (r=0·96, P<0·001). ©1997 SCI     

Cellulase inhibition by tannins in the testa of field beans (Vicia faba)

The testa of field bean varieties with coloured flowers contained 4–8 % tannin (measured as total phenolics) compared with less than 0.6 % in the testa of white flowered varieties. The tannin present in whole beans was almost entirely contained in the testa. The presence of high levels of tannin reduced in vitro digestibility and solubility in cellulase solutions of the testa and addition of high tannin testa decreased the solubility of cotyledon protein in acid pepsin. Water extracts of the testa from coloured-flower varieties inhibited the action of fungal cellulase and reduced the in vitro digestibility of white flowered testa and cellulose. A highly significant relationship (r= ?0.93***) was found between the tannin content and solubility in cellulase of testa for a range of 24 varieties. It is concluded that the effect of testa tannins on in vitro digestibility can be mainly attributed to their effect on cell wall digesting enzymes rather than an effect on protein solubility per se.     

Chemical Composition,Amino Acid Content and Protein Quality of the Little-Known Legume Bauhinia purpurea L

Some nutritional and antinutritional characteristics and biological value of Bauhinia purpurea L seeds were studied. The mature seeds contained (g kg^-1 as is) 271·7 crude protein, 58·7 crude fibre, 124·5 crude fat, 29·3 ash and 515·3 carbohydrates. Potassium, phosphorus and iron occurred in higher concentrations when compared with commonly consumed legumes. The globulins and albumins together constituted major storage proteins (82% total protein). The essential amino acid profile of total seed proteins compared well with the FAO/WHO reference pattern except for a deficiency of sulphur-containing amino acids and tryptophan. When compared with the globulins, the albumins appeared to be a rich source of cystine, methionine, threonine, lysine and tryptophan. Seed lipids contained high levels of the unsaturated fatty acids, oleic and linoleic, which accounted for 62·6% of total fatty acids recovered. Both dry heating and autoclaving significantly reduced the antinutritional compounds. The in vitro protein digestibilities of raw, dry-heated and autoclaved seeds were 59·5, 72·3 and 78·7%, respectively. True digestibility and net protein utilisation were significantly higher in processed seed samples compared with raw seeds. Regarding utilisable protein, autoclaved samples exhibited relatively higher values than raw seeds. © 1997 SCI.     

The nutritional value of two cereal-based foods in Nigeria

Two cereal-based foods fortified with soybean flour, vitamins and minerals were evaluated for their nutrient composition and protein quality. Results presented suggest that both ‘Soy-ogi’ and ‘Belona’ contain no trypsin inhibitors or other growth-inhibiting substances. Both have adequate amounts of the essential amino acids, high protein content and in vitro digestibility values of 78% and 80%, respectively. Soy-ogi and Belona have protein efficiency ratio (PER) values of 1·35 and 2·54, respectively, assuming respective digestibility values of 78% and 80·8% for the samples and 93% for casein.     

Nutritional and anti-nutritional characteristics of mucuna (Mucuna utilis) bean seeds

Some nutritional and anti-nutritional characteristics of mucuna (Mucuna utilis (Wight) Burck) bean seeds were studied. The mature seeds contained 264 g crude protein, 63 g crude fibre, 41 g crude fat, 37 g ash and 595 g carbohydrates kg^?1 DM. The essential amino acid profile compared well with the FAO/WHO scoring pattern except for a deficiency of sulphur-containing amino acids. Mineral composition was similar to those reported for most tropical grain legumes. Raw mucuna seed samples contained moderately high levels of anti-tryptic activity (2170 trypsin units inhibited g^?1 DM), but this was completely destroyed by cooking. The other anti-nutritional factors (phytate, cyanide and tannins) are probably of little nutritional significance provided that the beans are properly processed. The in-vitro protein digestibility of raw and cooked beans were 71·5 and 80·3 %, respectively. In view of the high L-DOPA contents reported in some mucuna cultivars, overconsumption of mucuna beans should be viewed with some caution until suitable processing methods are developed.     

Chitosan inhibits growth of spoilage micro-organisms in chilled pork products

The aim of this study was to develop novel preservation systems for chilled, comminuted pork products that are sold raw using the natural compound chitosan (polymeric ß -1,4- N -acetylglucosamine). In vitro testing showed that viable numbers of Saccharomycodes ludwigii were reduced by up to 4 log cfu ml⁻¹ on exposure to 0·05% chitosan in 0·9% saline at pH 6·2. Higher concentrations of chitosan (0·25 and 0·5%) were required to achieve similar levels of inactivation withLactobacillus viridescens, Lac. sake and Listeria innocua. Torulaspora delbrueckii and Salmonella enteritidis PT4 were resistant to chitosan at the concentrations tested in this study (up to 0·5%). Trials in real foods showed that dipping of standard and skinless pork sausages in chitosan solutions (1·0%) reduced the native microflora (total viable counts, yeasts and moulds, and lactic acid bacteria) by approximately 1–3 log cfu g⁻¹ for 18 days at 7°C. Chitosan treatment increased the shelf-life of chilled skinless sausages from 7 to 15 days. Addition of 0·3 and 0·6% chitosan to an unseasoned minced pork mixture reduced total viable counts, yeasts and moulds, and lactic acid bacteria by up to 3 log cfu g⁻¹ for 18 days at 4°C compared with the untreated control. The results indicated that chitosan was an effective inhibitor of microbial growth in chilled comminuted pork products.     

The effect of soaking,germination and cooking on the protein quality of mash beans (Phaseolus mungo)

The protein quality of mash beans (Phaseolus mungo) as affected by soaking, germination and cooking was determined at the 10% dietary protein level using weanling rats. Gains in body weight were 11.5 g for raw beans, 68.5 g for soaked-cooked and 33.0 g for germinated-cooked beans. The protein efficiency ratio values were 0.4, 1.9 and 1.1 for raw beans, soaked-cooked and germinated-cooked beans respectively. Net protein utilisation was improved from 44% for raw beans to 58% after soaking and cooking, but reduced to 47% after germinating and cooking. These changes were entirely accounted for by changes in digestibility, 72, 90 and 81% respectively, and biological values were unchanged at 61, 64 and 59 respectively.     

Thermal Effects on Net Protein Ratio of Red Kidney Beans (Phaseolus vulgaris L)

Net protein ratio (NPR), predicted-protein efficiency ratio (P-PER), relative NPR (RNPR), and corrected RNPR (CRNPR) of thermally processed red kidney beans were estimated in rats and compared to in vitro protein digestibility-corrected amino acid score (AAS_IVDP), and computed-protein efficiency ratio (C-PER). Thermal processing had a significant effect on protein intake, NPR, P-PER and CRNPR values of beans. Changes in protein intake suggest that heat processing had an effect on the palatability of the beans. Home-cooked beans and commercially canned beans had higher NPR values than beans autoclaved at 128°C for 20 min, while beans autoclaved at 121°C for 10–90 min had intermediate values. High correlation coefficients between P-PER and C-PER, CRNPR and C-PER, and CRNPR and AAS_IVDP (r=0·990, 0·992 and 0·960, respectively, P<0·001) were observed.     

Effects of micronising on the utilisation of field beans (Vicia faba L.) by the young chick

The major changes in the composition of field beans (Vicia faba L.) caused by micronising were as follows: the moisture content was reduced from 16.5 to 13.2%, the trypsin inhibitor activity reduced from 2.49 to 0.21 trypsin inhibitor units/mg dry matter and the available carbohydrate content raised from 40.6 to 50.2%. Growth and food consumption of broiler chicks from 1 to 2 weeks of age were not affected significantly when micronised beans replaced raw beans in their diets at a level of 300 g/kg. However, food conversion efficiency, apparent dry matter digestibility and nitrogen retention were significantly improved and pancreas size significantly reduced when the birds were fed the diet containing the micronised beans. The nitrogen-corrected metabolisable energy (m.e.) of the diet containing 500 g of micronised beans/kg (10.88 MJ/kg) was significantly higher than that of a diet containing 500 g of raw beans/kg (10.33 MJ/kg). It was calculated that the m.e. of the beans had been raised from 10.59 to 11.67 MJ/kg dry matter by micronisation. The improvement in nutritive value is attributed partly to the destruction of the trypsin inhibitor and partly to the increased availability of the carbohydrate fraction of the beans.     

Thermal Effects on in vitro Protein Quality of Red Kidney Bean (Phaseolus vulgaris L.)

Significant thermal effects on in vitro protein quality of red kidney beans were observed. Beans autoclaved at 121°for 10 and 20 min, and common home-cooked beans had improved protein quality. Uncooked beans, and those autoclaved at 128°for 20 min and at 121°for 90 min had reduced protein quality compared to canned beans and those autoclaved at 110°for 20 min and at 121°for 40 and 60 min. Amino acid scores, essential amino acid index and available lysine (%), corrected for in vitro protein digestibility gave comparable results in evaluation of protein quality. Specific lysine, methionine, cysteine and other amino acid ratios overestimated protein quality.     

The chemical composition,the nutritive value and the functional properties of malt sprout and its components (acrospires,rootlets and husks)

The components of malt sprouts were effectively separated by manual winnowing into acrospires (15·3%), rootlets (40·1%) and husks (43·7%). The bitter taste was located in the acrospires. Percent recovery of protein and fibre was, respectively, 95·2 and 87·2 of malt sprouts. The acrospires were rich in protein (30·3%) and sugars (45·7%) but low in calcium (1·94 g kg⁻¹), fibre content (4·6%) and essential amino acids. They had moderate functional properties. The rootlets were rich in calcium (19·9 g kg⁻¹) and in protein (31·9%), which had a good nutritive value (low in phytic acid and polyphenols content). They had a moderate fibre content (10·7%). Consequently, they had the highest water absorption, oil absorption and emulsification capacities. The rootlets had relatively low foam capacity but the highest foam stability. The husks were rich in fibre content (25%) but moderate in protein content (12·4%), which was rich in essential amino acids. The husks were relatively low in calcium (11·83 g kg⁻¹) and phosphorus (6·53 g kg⁻¹) contents and in vitro protein digestibility (68·9%). Their functional properties were influenced by high fibre and moderate protein contents. The first limiting amino acids were sulphur-containing ones in the malt sprouts, the acrospires and the rootlets, but it was leucine in the husks. © 1997 SCI.     

Rohament P as a processing aid in Medammis preparation

Two lots of dry faba bean (Viciufubu L.) seeds of different cookabilities were used to prepare Medammis which is considered as a staple food for the majority of the population in Egypt. Seeds were soaked with shaking in a citrate buffer of pH 4.5 containing 0.1 % Rohament P enzyme at 45°C for 12 h. After draining and washing, beans were mixed with distilled water at 1:4 ratio (w/v) and autoclaved at 115°C for 2 h. No obvious differences were observed for the hydration coefficients of beans soaked in presence and/or absence of enzyme. In contrast, cooked beans exhibited appreciable textural differences as assessed objectively for the control and treated samples. Moreover, hard-to-cook beans were softened to the acceptable texture as the five fold of enzyme concentration was applied. Data of quantitative and TLC methods clearly indicated leaching out of sugars as a result of maceration action of middle lamella by means of Rohament P.     

Announcement London

Grain samples of nine varieties of pearl millet (P. typhoides) and six varieties of ragi (E. coracona) were analysed before and after malting for total ash, phosphorus, phytin phosphorus, calcium, magnesium, iron, zinc, manganese, copper and chromium contents. Pearl millet alone varietal differences were significant for iron, manganese and chromium contents. Significant nutrient losses in malting were, in pearl millet: iron and manganese, 40%; copper, 30%, and phosphorus, 25% and, in ragi: calcium, 40%; zinc, 30% and copper 25%. As judged by an in vitro method, the availability of iron and zinc in millets improved several fold on malting. The values for ionizable iron (mg per 100 g of raw and malted grains) were 0·64 and 2·70 in pearl millet and 0·29 and 2·98 in ragi. Soluble zinc contents per 100 g of raw and malted grains, respectively were 2·04 and 5·25 mg in pearl millet and 2·15 and 3·24 mg in ragi. Reduction in phytin phosphorus on malting of these millets partly explained the improved availability of iron and zinc.     

Chemical Composition and Nutritional Quality of Faba Bean (Vicia faba L. Minor) Based Tofu

Chemical composition and antinutritional factors in soy and faba beans and tofus produced thereof were evaluated. Both bean curds had higher protein contents (55.7 and 82.0% dry basis for soy and faba bean curds, respectively) than the corresponding raw beans. Tofu made from faba bean (FBT) contained only 1.5% total lipids (dry basis) compared to 34.4% in soybean tofu (SBT). Antinutritional and flatulence factors were much lower in FBT. Favism factors were not examined. In vitro studies showed that SBT and FBT are comparable in terms of digestibility and amino acid availability.     

Protein supplementation of broad beans with sesame

Feeding experiments with weanling rats indicated that the protein of broad beans (Vicia faba var. major) and sesame (Sesamum indicum) are mutually supplementary. A standard diet in which 75% of the protein was provided by broad beans and 25% by sesame had a protein efficiency ratio (PER) of 2·36 compared to a casein PER adjusted to 2·50. A similar diet in which broad beans and sesame contributed equal amounts of protein had a PER of 2·41. The PER of broad beans was 0·99 and that of sesame 1·55.