Effect of dry heat on the in vitro digestibility and trypsin inhibitor activity of chickpea flour

The effect of a dry heat treatment on trypsin inhibitors, protein quality and molecular weight of products obtained from enzymatic hydrolysis of chickpea flours was analysed in order to use chickpeas as food protein hydrolysates. Chickpea flour obtained from dehusked seeds was processed under different conditions, either by heating or enzymatic treatment. Heat treatment at 140 °C for varying times (1–24 h) inactivated trypsin inhibitors and facilitated enzymatic treatment but showed an unacceptable loss in the nutritional quality of the protein for heating times longer than 6 h. Enzymatic treatment with a commercial protease, Alcalase 0.6L, at pH 8 and 50 °C, increased the protein nutritional value of the chickpea by breaking the protein chains into shorter peptide chains more suitable to human nutrition.     

Effect of processing on antinutrients and in vitro protein digestibility of kidney bean (Phaseolus vulgaris L.) varieties grown in East Africa

The effects of hydration, autoclaving, germination, cooking and their combinations, on the reduction/elimination of antinutrients, flatus-producing compounds and the improvement of in vitro protein digestibility of three selected Phaseolus vulgaris varieties were investigated. Reduction in the amount of total α-galactosides was attained by employing hydration process and was due to the differential solubility of the individual oligosaccharides and their diffusion rates. Due to their heat-sensitive nature, saponins, trypsin inhibitors and phytohaemagglutinins, diminished drastically to undetectable amounts when heating processes (cooking and autoclaving) were employed. Hydration and germination processes were less effective in reducing trypsin inhibitors, saponins and phytohaemagglutinins as compared with cooking/autoclaving processes. Germination process reduced stachyose, raffinose, phytic acid and tannins which was due to metabolic activity. The combination of germination followed by autoclaving processes yielded the most promising result in this study. The bean variety Roba exhibited better protein digestibility on processing and thus has high potential to be used as a raw material for the manufacturing of value-added products.     

Vicia faba beans vs. soyabean meal as a source of protein

The protein value of raw, heated and shelled Vicia faba beans (VFB) was compared with that of heated soyabean meal (HSB) when fed at 10 and 15% protein levels to rats of both sexes. While females grew equally well on VFB and HSB diets containing 15% protein, males fed VFB grew more slowly than those fed HSB at the two levels of protein in the diets (the difference being smaller on the 15% protein diet). The lower N utilisation of VFB seems to be the main reason for the differences in the growth response. Shelling improved the nutritive value of VFB, while autoclaving affected it adversely. The trypsin inhibitors of the VFB were not destroyed by autoclaving.     

Nutritional value of cowpea (Vigna unguiculata L. Walp) meals as ingredients in diets for Pacific white shrimp (Litopenaeus vannamei Boone)

The nutritional value of cowpea (Vigna unguiculata L. Walp) meals, as ingredients in diets for Litopenaeus vannamei, was evaluated. Five experimental meals were prepared in the laboratory: whole raw cowpea (WRC), dehulled (DC), cooked (CC), germinated (GC) and extruded (EXC). The crude protein content of WRC (26.1%) increased after germination (29.5%). Carbohydrates ranged from 69.4% to 85.9%. The trypsin inhibitor activity of WRC meal was low (7.52 U/mg dry matter), and was reduced or eliminated by cooking and extrusion. Apparent digestibility of dry matter, protein and carbohydrate of the diet containing whole raw cowpea meal (71.1%, 85.9% and 76.7%, respectively) was similar to the control diet. Cooking and extruding of cowpea significantly increased dry matter, protein and carbohydrate digestibility in the diets. The results suggest that cowpea meals are good sources of nutrients and can be used as ingredients in diets for L. vannamei.     

The influence of selected technological processes on the improvement of rapeseed meal and flour feed quality. Part 2. Effect of hydrothermal treatment and ethanol extraction on the nutritional value of rapeseed products

In experiments with rats the effect of feeding flours (dehulled and defatted seeds) and concentrates (flour extracted with ethanol) prepared from non-heated and heated seeds of low-glucosinolate rapeseed var. Jantar was studied. Flours and concentrates were fed either as the main protein supplement in cereal-based diets or as the only protein sources in semi-synthetic diets; ethanolic extracts were either administered by stomach tube or fed with the diets. Heat treatment of seeds reduced ITC + VOT contents about 27 % and did not affect phenol contents; ethanol extraction removed both ITC + VOT and phenols. Feeding the flours from heated and non-heated seeds resulted in the increase of thyroid and liver weights as compared with rats from the control group fed on soybean diet. Heat treatment of seeds improved protein digestibility of flours and concentrates and did not modify negative effect of ethanol extract on protein digestibility. Biological value of protein of flours and concentrates was not affected by heat treatment of seeds. Feeding concentrates influenced positively animal growth performance, elimenated hypertrophic effect of the flour on thyroid and liver, increased biological value of protein as compared with flour. Administration of ethanolic extracts containing ITC + VOT and phenols to rats fed on soya-bean mael diet did not induce hypertrophy of thyroid and liver similar to that observed in rats fed on flours containing these antinutritional substances.     

Enzymatic modification as a tool to improve the functional properties of heat‐processed soy flour

BACKGROUND: There are a number of antinutritional factors present in soybeans that exert a negative impact on the nutritional quality of the protein. Among those factors that are destroyed by heat treatment are protease inhibitors and lectins. Protease inhibitors show antinutritional effect and moreover the digestibility of the protein is limited by the presence of these antinutrients. The aims of the present study are (1) to study the effect of autoclaving on the trypsin inhibitor inactivation, nitrogen solubility and protein digestibility of defatted soy flour and (2) to study the effect of enzymatic modification on the functional properties of autoclaved soy flour. RESULTS: The solubility of the soy flour decreased with increase in autoclaving time. Partial hydrolysis of the autoclaved soy flour increased its acid solubility (pH 4.5) from 17% to 56% over a control value of 24% without affecting its functional properties. Inactivation of trypsin inhibitors improved the protein digestibility of soy flour from 25% to 95%. Particle size analysis of the autoclaved flour indicated the formation of soy protein aggregates, which resulted in poor solubility. The enzymatic modification of autoclaved soy flour resulted in its property as a good emulsifying agent with an emulsion capacity of 118 ± 4 mL. CONCLUSION: Enzymatic modification of the heat‐processed soy flour increased its solubility and other functional attributes. The increased acid solubility would be advantageous in the utilization of soy proteins in acidic foods. Thus the autoclaved and partially modified soy flour is a potential source for specific functional foods. Copyright © 2007 Society of Chemical Industry     

Effects of heat treatments of antinutritional factors and quality of proteins in winged bean

The effects of heat treatments, namely microwave, infrared, hot air oven, autoclaving and cooking in boiling water, on trypsin inhibitor and haemagglutinating activities, tannin and phytate contents, essential amino acid composition and quality of proteins in winged bean, were investigated. The infrared, autoclaving and boiling-water treatments destroyed most of the trypsin inhibitor and haemagglutinating activities, and reduced the level of tannins. However, the microwave and oven heat treatments had no effect on these constituents of winged bean meal. Lysine and valine contents in the meals from infrared, autoclaving and cooking in boiling water treatments were lower than in untreated meal. There was a significant loss of threonine and arginine due to cooking of beans in boiling water. None of the treatments had any effect on phytate content. Rats fed on untreated, microwave-treated and oven-heated meal diets had low dry-matter intakes and lost weight significantly. However, remarkable improvements in dry-matter intake and weight gain were recorded for the diets containing meal from infrared, autoclaving and boiling-water treatments. The digestibility of proteins in the meal improved from 50 to 84% as a result of infrared and boiling-water treatments, whereas a noticeable decrease in protein digestibility was observed in oven-heated meals. There was a significant improvement in biological values and net protein utilisation values for the diets containing meals from infrared, autoclaving and boiling-water treatments over those of a diet having untreated meal.     

Chemical composition and nutritional attributes of selected newly developed lines of soybean (Glycine max (L) Merr)

The chemical composition and nutritional properties of raw, autoclaved and boiled samples of three promising advanced breeding lines of soybean (TG_x 923 ? 2^EN, TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D), part of a larger collection evaluated in agronomic field trials in Nigeria, were investigated. Protein quality was evaluated using weanling albino rats fed diets which were formulated to supply 10% protein using soybean samples, with casein as a control. Raw seeds contained 35.6–42.4% crude protein, 8.9–9.8 mg iron per 100 g, 8.62–18.21 mg trypsin inhibitor g^?1 and 2.25–6.15 mg phytic acid g^?1 seed flour. TG_x 923 ? 2^EN possessed higher crude protein contents and lower amounts of trypsin inhibitor, polyphenol and phytic acid compared with TG_x 1019 ? 2^EN or TG_x 1497 ? 1^D. Boiling proved more effective than autoclaving for reducing the levels of antinutrients and improving the protein quality of the beans, as shown by the higher values for weight gain, protein efficiency ratio (PER), net protein ratio (NPR) and true digestibility (TD) of boiled samples. There were no significant (p > 0.05) differences between the values obtained for PER, NPR and TD of diets containing boiled samples of TG_x 923 ? 2^EN and casein, indicating the nutritional superiority of this soybean line compared with TG_x 1019 ? 2^EN and TG_x 1497 ? 1^D. © 2002 Society of Chemical Industry     

Nutritional quality of yam (Dioscorea dumetorum and D rotundata) flours for growing rats

The digestibility and metabolism of diets based on flours prepared from raw, boiled or steamed tubers of the sweet yam (Dioscorea dumetorum) were evaluated in growing albino rats by the balance method in comparison with diets containing similar flours from the popular white yam (D rotundata). The results show that whatever their method of preparation, flours from D dumetorum promote higher growth rate and have higher nutritional value in the growing rat than corresponding D rotundata flours. This can be attributed to the good digestibility of D dumetorum starch which facilitates digestibility and absorption of nitrogen and other nutrients. Moisture-heat treatment of tubers before processing into flour improves the nutritional value, especially for D rotundata.     

Heat Inactivation of Protease Inhibitors in a Soybean Line Lacking the Kunitz Trypsin Inhibitor

The effect of heat treatment (autoclaving at 121°C, 15 psi for various periods of time) on the trypsin- and chymotrypsin-inhibitor activities of a soybean line lacking the Kunitz trypsin inhibitor (SBTI) was compared to that of commercial untoasted soy flour. The trypsin- and chymotrypsin-inhibitor activites of the SBTI-free soybeans were approximately one-half and three-fourths that of the soy flour, respectively. Less heat treatment was required to produce a given level of destruction of these inhibitor activities in the case of the SBTI-free soybeans than with the soy flour. The effect of heat on the ratio of chymotrypsin- to trypsin-inhibitor activities was notably different between the two soybean samples and presumably reflects differences in the amounts and thermal stability of the various protease inhibitors known to be present in soybeans. The nutritional implications of these findings are discussed.     

Levels of nutritional constituents and antinutritional factors in black gram (Vigna mungo L. Hepper)

A study was conducted on nutritional constituents (total sugars, total proteins, total lipids and starch content) and antinutritional factors such as phenolic compounds, tannins, saponins, phytic acid, trypsin inhibitors and enzymes related to them such as acid- and alkaline phosphatases, ??-galactosidase in eleven recommended cultivars and twenty one advance breeding lines of black gram (Vigna mungo L. Hepper) with an aim to identify genotypes containing high nutritional quality and low antinutritional content. The average content of starch, total soluble sugars, proteins and lipids was around 43.5, 4.84, 22.0 and 1.1%, respectively. Seven genotypes had higher levels of bound fructose contributed by sucrose and raffinose series oligosaccharides. A significant positive correlation was observed among total phenols, o-dihydroxy phenols and flavonols; and among trypsin inhibitors and saponins. The content of phytic acid and activity of trypsin inhibitors showed significant variation among these genotypes. However, not much variation was observed in the content of tannins and saponins. Activities of ??-galactosidase, acid- and alkaline phosphatase were found to be related to the content of bound fructose of raffinose series oligosaccharides and phytic acid respectively. Genotypes having higher activity of these enzymes showed lower content of these antinutritional factors. The results showed that the observed diversity in developed cultivars and advance breeding lines could be further used by plant breeders.     

Effect of particle size of soft wheat flour on the development of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

The effect of soft wheat flours, characterized by different particle size, protein and starch content, on the development of Ephestia kuehniella was studied. The attractiveness of the substrata to first and third instar larvae was also considered.The different protein content of the flours did not significantly affect the development of E. kuehniella, nor did it affect the ability of the flours to attract larvae. In tests with soft wheat flours with the same nutritional value but different particle size, the highest mean number of adults and the shortest developmental period were recorded on samples with greatest particle size (250-419 μm).In order to test the attractiveness of soft wheat flour to larvae, a one-way olfactometer was used. There were no significant differences observed in the number of first and third instar larvae found on flours with different protein composition and particle size. Larvae of this species show limited mobility, in fact few individuals of either instar can reach the flour from a distance of 2 m. No larvae of either instar contacted the different substrata from a distance of 2.5 m.     

Influence of enzymatic treatment on the nutritional and functional properties of pea flour

The effect of enzymatic treatment on the nutritional value and functional properties of pea flour was investigated. Pea flour was hydrolyzed with acid protease from Aspergillus saitoi, to give two different hydrolyzed pea flours. This enzymatic treatment led to a significant (p < 0.05) decrease in crude and true protein and to an increase of free amino acids and non-protein nitrogen. The nutritional value decreased, but an increase in the avilability of protein was expected as result of lower trypsin inhibitor activity and phytic acid content in hydrolyzed pea flours. The amino acid profile of unhydrolyzed pea flour was slightly modified after enzymatic hydrolysis, increasing (significantly) the isoleucine, leucine, lysine, cystine, phenylalanine, threonine, alanine, arginine and aspartic acid contents as a result of the added enzyme. In addition, enzymatic treatment released hydrophobic amino acids, which significantly improved the protein solubility at acid pH, the oil absorption capacity and the emulsification capacity of pea flours. Protein solubility, foaming capacity, foam stability, water absorption capacity, gelation capacity and green colour decreased. It was thus confirmed that treatment with acid protease improves some functional properties of pea flour, but the effect on nutritional properties was unclear.     

大豆粉对馒头品质影响的研究

通过向小麦粉中添加全脂豆粉、脱脂豆粉及大豆蛋白,来研究其对小麦粉及馒头品质的影响.结果表明:随着全脂豆粉、脱脂豆粉及大豆蛋白使用量的增加,小麦粉湿面筋含量与沉降值逐渐下降,馒头的比容逐渐减小,品质逐渐变差;但当全脂豆粉与脱脂豆粉添加量在10%以内,大豆蛋白的添加量在5%以内时不会对馒头的品质产生不良影响,还可以弥补馒头中必需氨基酸特别是赖氨酸的不足,提高馒头的营养价值.     

固态发酵豆粕的不同生产工艺及其营养品质比较

以米曲霉和植物乳杆菌WZ011为发酵菌种,研究了5种不同的固态发酵豆粕生产工艺及其营养品质。以灰分、粗蛋白量、可溶性蛋白量、游离总氨基酸量、氨基酸含量分布、酸溶性蛋白量、小肽含量、还原糖量、氮溶指数、蛋白分子量、脲酶含量、胰蛋白酶抑制因子含量以及体外消化率为指标,对发酵豆粕营养品质进行了比较和分析。结果表明,米曲霉单菌发酵后,高温水解处理对豆粕营养品质的提高有效,但在米曲霉和植物乳杆菌WZ011的双菌串联发酵过程中增加高温水解处理反而不利。在米曲霉有氧发酵后直接接种植物乳杆菌WZ011进行厌氧发酵条件下所得的豆粕营养品质最优,其中的胰蛋白酶抑制因子含量比原豆粕减少了91.8%,并含有小肽8.01%、乳酸4.95%、γ-氨基丁酸0.317 mg/g以及植物乳杆菌活菌数1.93×1010CFU/g。优化的豆粕发酵工艺操作简单且无污染,其产品富含营养。该工艺在饲料加工行业和养殖业具有应用意义。     

Jatropha platyphylla, a new non-toxic Jatropha species: Physical properties and chemical constituents including toxic and antinutritional factors of seeds

Local communities in Mexico consume Jatropha platyphylla seeds after roasting. The kernels of J. platyphylla contained ca. 60% oil and were free of phorbol esters. The kernel meal of this Jatropha species contained trypsin inhibitor, lectins and phytate. However, trypsin inhibitor and lectins are heat labile so this explains why the local people can eat roasted seeds without ill effects. Heat-treated J. platyphylla kernel meal (JPKM) was free of trypsin inhibitor and lectin activities. Crude protein content of JPKM was 75%. Heated JPKM and soybean meal were included in a standard diet (crude protein 36%) for Nile tilapia (Oreochromis niloticus) to replace 50% of the fish meal protein. The growth of fish in all the three groups was statistically similar and the blood biochemical parameters that serve as biomarkers for toxicity were within the normal ranges. This is the first study that confirms the non-toxic nature of J. platyphylla.     

Thermal inactivation of trypsin inhibitors of soybean preparations added to meat

The activity of trypsin inhibitors was investigated in minced meat in which 30% of meat protein was replaced by soybean preparations (flakes, concentrate, isolate, textured flour). Trypsin inhibitors were determined in 20% suspensions of these soybean preparations. The activity of trypsin inhibitors in soybean preparations added to meat, or suspended in water, appeared to be higher than that of dry products. The heat treatment (70, 80, 90 and 100°C for 15 min) reduced the inhibitor activity in all soybean preparations, both in model meat systems (MMS) and in suspensions. Trypsin inhibitor activity was higher in MMS than in water suspensions of soybean preparations, suggesting that meat components protect trypsin inhibitor proteins against heat treatment. Trypsin inhibitor activity in heated meat model systems was too low to produce unfavourable nutritional effects.     

Production of gluten‐free bread using soybean flour

The effect of soybean flour on gluten‐free bread quality was studied. Full‐fat enzyme‐active, semiactive and inactive soybean flours were evaluated. Active soybean flour improved the volume and structure of gluten‐free bread, while semiactive and inactive soybean flours did not have positive effects on bread quality. The particle size and concentration of the soybean flours also affected bread quality. Levels of addition between 125 and 150 g kg^?1 and particle sizes between 90 and 120 µm of active soybean flour yielded the best results. Heating the active soybean flour destroyed its improving effect. The analysis of proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis and size exclusion chromatography showed that heating soybean flour at 60–200°C caused protein aggregation. The overall results indicated that the addition of active soybean flour improved gluten‐free bread quality, and this effect seemed to be due to both the structural proteins and the enzymatic activities of the soybean flour. Copyright © 2004 Society of Chemical Industry     

Effects of germination on the physicochemical,nutritional and in vitro digestion characteristics of flours from waxy and nonwaxy proso millet,common buckwheat and pea

Germination can increase the nutritional quality of flours and change their physicochemical properties. In the present study, waxy and nonwaxy proso millet, common buckwheat and pea were germinated for different duration of time (i.e. 0, 1, 2, 3 and 4 d). Subsequent changes in their nutritional, physicochemical and in vitro digestion characteristics induced by germination were assessed and compared. Overall, germination significantly decreased amylose and starch contents and increased the α-amylase activity and contents of crude fibre, soluble sugars, free amino acids and bioactive components of the flours, revealing this physically efficient treatment for improving the nutritional richness of flours. Germination also affected the physicochemical properties and in vitro starch digestibility of these four flours, though it had different effects on their protein digestibility. These findings inform the application of germination in generating nutritionally rich flours with altered physicochemical properties.     

Effect of soaking,dehulling, and cooking methods on certain antinutrients and in vitro protein digestibility of bitter and sweet lupin seeds

Effect of several physical treatments (soaking, dehulling, ordinary cooking, microwave cooking, and autoclaving) on the level of antinutrients and in vitro protein digestibility of bitter and sweet lupin seeds were investigated. The raw bitter and sweet lupin seeds were found to contain phytic acid, tannins, trypsin inhibitor activity, and lectin activity, but α-amylase inhibitor was absent. Dehulling significantly increased the levels of phytic acid (PA), trypsin inhibitor activity (TIA), and tannins, but lectin activity was not changed. Also soaking in bitter (for 96 hr) and sweet (for 24 hr) seeds caused a significant increase in these factors except lectin activity. Cooking methods differently affected the levels of the antinutrients. Thus, PA increased but tannins were not changed, on the other hand TI and lectin activities were inactivated; ordinary cooking and autoclaving were the most effective in both seeds. For combination effect, soaking following cooking treatments significantly decreased PA, tannins, and lectin activity, but increased TIA in both seeds. Moreover, dehulling following soaking and cooking methods resulted in a significant increase of PA, TIA, and tannins. In vitro protein digestibility (IVPD) of raw bitter and sweet lupin seeds were 78.55 and 79.46%, respectively and it was improved by all processing methods; soakingdehulling after autoclaving was the most effective in both seeds. Although some treatments increased the level of antinutrients, they improved IVPD. Therefore, the studied antinutrients are not the only responsible factor for lowering IVPD.