Trypsin Inhibitor Content Research Articles

Kunitz trypsin inhibitor in addition to Bowman-Birk inhibitor influence stability of lunasin against pepsin-pancreatin hydrolysis

Soybean contains several biologically active components and one of this belongs to the bioactive peptide group. The objectives of this study were to produce different lunasin-enriched preparations (LEP) and determine the effect of Bowman-Birk inhibitor (BBI) and Kunitz trypsin inhibitor (KTI) concentrations on the stability of lunasin against pepsin-pancreatin hydrolysis (PPH). In addition, the effect of KTI mutation on lunasin stability against PPH was determined. LEP were produced by calcium and pH precipitation methods of 30% aqueous ethanol extract from defatted soybean flour. LEP, lunasin-enriched commercially available products and KTI control and mutant flours underwent PPH and samples were taken after pepsin and pepsin-pancreatin hydrolysis. The concentrations of BBI, KTI, and lunasin all decreased after hydrolysis, but they had varying results. BBI concentration ranged from 167.5 to 655.8μg/g pre-hydrolysis and 171.5 to 250.1μg/g after hydrolysis. KTI concentrations ranged from 0.3 to 122.3μg/g pre-hydrolysis and 9.0 to 18.7μg/g after hydrolysis. Lunasin concentrations ranged from 8.5 to 71.0μg/g pre-hydrolysis and 4.0 to 13.2μg/g after hydrolysis. In all products tested, lunasin concentration after PPH significantly correlated with BBI and KTI concentrations. Mutation in two KTI isoforms led to a lower concentration of lunasin after PPH. This is the first report on the potential role of KTI in lunasin stability against PPH and must be considered in designing lunasin-enriched products that could potentially survive digestion after oral ingestion.

Effects of defoliation and site quality on growth and defenses of Pinus pinaster and P. radiata

The susceptibility to pests and pathogens is frequently of only minor consideration by foresters when selecting tree species to plant, but growth reductions from pests and pathogens are commonly large relative to productivity differences among tree species. Because the selection of tree species and sites when establishing plantation forests has potential effects on subsequent damage by pests, there is need for consideration of joint effects of tree species, site quality, and risk of pests. We tested here how site quality influences the response of two pines species that differ in their evolutionary history with a primary pest in the system. Our specific research objectives were to (1) measure the growth response of two pine species (the native Pinus pinaster and the introduced P. radiata) to defoliation by the pine processionary moth, across a gradient of nutrient availability and (2) compare the constitutive and delayed defoliation induced chemical defenses of these two pine species on sites of low and high quality. We analyzed variation in foliar nitrogen, terpenes, tannins, total phenols and four defensive proteins. The impact on tree growth from experimentally applied defoliation by PPM was surprisingly low. Even with complete defoliation, large sample sizes, and baseline measurements that accounted for much of the variation among trees, we observed only modest effects on diameter growth and no effects on height growth; volume growth was initially reduced by only 6–8% initially, with full recovery within 3 years of defoliation. Pinus radiata, the faster growing species, had higher concentrations than P. pinaster of foliar N while P. pinaster had up to 12 times higher concentrations of terpenes, these results match with predictions of the resource availability hypothesis (RAH). Pinus radiata foliage was relatively rich in tannins and total phenolics. The pine species also differed in defensive proteins. Pinuspinaster had higher concentrations of peroxidase (POD), polyphenol oxidase (PPO) and chitinase (CHI), while P. radiata had higher concentrations of trypsin inhibitor (TI). Finally there was no evidence for delayed inducible defenses in either pine species following PPM defoliation; both species seem to use other defensive strategies to counter predictable attacks by the herbivore. In our study region, defoliation by PPM may not be a primary consideration in the selection of pine species for production forests, but this conclusion need not hold in regions where pines grow more slowly or are exposed to multiple years of defoliation by PPM.

Continuous method to determine the trypsin inhibitor activity in soybean flour

The determination of trypsin inhibitor (TI) activity is of importance to evaluate the nutritional value of soybean flours. An analytical method, which involves a continuous spectrophotometric rate determination for trypsin activity against the substrate N-benzoyl-DL-arginine p-nitroanilide, is proposed as an alternative to the standard discontinuous assay. Stopping the reaction with acetic acid and a centrifugation/filtration step to decrease turbidity are not required, thus reducing costs and sample preparation time.The TI activity of different flour samples, determined by both assays, demonstrated to be statistically comparable, irrespective of the TI concentration level. The coefficients of variation of the novel method did not exceed 8% at any concentration level.The curves of progress reaction showed a non-linear behavior in samples without TI. A reduction of incubation time from 10min to 2min increased the method sensitivity and extended its linear range.A more economical, faster and simpler assay was developed.

Effect of chemical stress on germination of cv Dalia bean (Phaseolus vularis L.) as an alternative to increase antioxidant and nutraceutical compounds in sprouts

The aim of this study was to determine the effect of chitosan (CH), salicylic acid (SA) and hydrogen peroxide (H2O2) at different concentrations on the antinutritional and nutraceutical content, as well as the antioxidant capacity of bean sprouts (cv Dalia). All elicitors at medium and high concentrations reduced the antinutritional content of lectins (48%), trypsin inhibitor (57%), amylase inhibitor (49%) and phytic acid (56%). Sprouts treated with CH, SA and H2O2 (7μM; 1 and 2mM, and 30mM respectively) increased the content of phenolic compounds (1.8-fold), total flavonoids (3-fold), saponins (1.8-fold) and antioxidant capacity (37%). Furthermore, the UPLC-ESI-MS/MS analysis showed an increase of several nutraceutical compounds in bean sprouts treated with SA such as coumaric (8.5-fold), salicylic (115-fold), gallic (25-fold) and caffeic (1.7-fold) acids, as well as epigallocatechin (63-fold), rutin (41-fold) and quercetin (16.6-fold) flavonoids. The application of elicitors in bean seed during sprouting enhances their nutraceutical properties.

Plasma PP13 and urinary GAGs/PGs as early markers of pre-eclampsia

To evaluate at 11-13weeks' gestation biochemical markers that may predict complications of pregnancy such as pre-eclampsia, proteinuria, and hypertension. Analyses were performed on first-morning urine and plasma samples from first trimester pregnant women with increased risk of developing pre-eclampsia such as positive personal or family history of cardiovascular disease and diabetes mellitus. A total of 62 women were enrolled, 24 of them presented complications such as pre-eclampsia, proteinuria, and hypertension during pregnancy. The remaining 38 women had a physiological course of pregnancy and formed the reference group. Urine glycosaminoglycans/proteoglycans (GAGs/PGs) distribution was determined by electrophoresis on cellulose acetate strips. Urinary N-acetyl-β-glucosaminidase was estimated kinetically. Plasma levels of placental protein 13 (PP13) were measured by enzyme-linked immunosorbent assay. No significant differences in total GAG excretion and N-acetyl-β-glucosaminidase (NAG) concentration were observed between the two groups of pregnant women, whereas we detected increased relative content of total urinary trypsin inhibitor (UTI plus low-sulfated chondroitin sulfate) (p=0.001) and reduced excretion of heparan sulfate (p=0.007) and chondroitin sulfate (p=0.011) in women presenting with pregnancy complications respect to controls. Plasma levels of PP13 were significantly reduced in the group of women who went on to develop complications compared with controls (p=0.022). The reduced plasma levels of PP13 and the alteration of the relative content of urinary GAGs and PGs observed in our study could be a promising tool for the prediction of pre-eclampsia in an early stage of pregnancy.

Physiochemical and nutritional attributes of raw and soaked seeds of chickpea (Cicer arietinum L.) genotypes

The present investigation aims to analyze nutrient profile, antinutritional traits and physiochemical characteristics in raw (dry seeds) and water soaked seeds of eighteen chickpea genotypes comprising 16 cold stress tolerant and 2 susceptible. Raw seeds of tolerant genotypes were found to have higher total sugars and protein content and lower amount of trypsin inhibitors. Higher content of raffinose family oligosaccharides in tolerant genotypes is an additional characteristic for their tolerant behaviour and it does not interfere with the digestion as with soaking these oligosaccharides are reduced by 87%. The enhanced mineral content with soaking in tolerant chickpea genotypes might be attributed to the better physiochemical characteristics in terms of higher hydration capacity and swelling index which leads to greater permeable and softer cotyledons that might help in leaching out of mineral ligands. The higher nutritional value along with better physiochemical characteristics observed in tolerant genotypes render them useful at consumer level as well as from breeding point of view.

Chemical composition, amino acid digestibility, and true metabolizable energy of cowpeas as affected by roasting and extrusion processing treatments using the cecectomized rooster assay

SUMMARY Nutritional differences due to variety, source, and effects of heat processing on cowpeas (Vigna unguiculata) were assessed. The precision-fed cecectomized rooster assay was used to determine amino acid digestibility and TME of cowpeas. Mozambican cowpea (nhemba) treatments included either raw or roasted, whereas those (black-eyed beans) sourced from the United States were raw, roasted, or extruded. Crude protein content on a DM basis was similar for raw nhemba (296 g/kg) in comparison to raw black-eyed beans (299 g/kg). Raw nhemba had slightly higher amino acid content (except tryptophan) than raw black-eyed beans. The level of trypsin inhibitors of nhemba was 3 times higher than black-eyed beans (6,700 vs 2,200 TIU/g). Heat treatment generally had no effect on amino acid concentration except for lysine, which was reduced in both beans by heat. Additionally, all heat treatments reduced the concentration of trypsin inhibitors to below 2,000 TIU/g. Amino acid digestibility for the nhemba cowpeas was lower than for the black-eyed cowpeas except for tryptophan. Roasting had no effect on amino acid digestibility in black-eyed beans, but increased digestibility of several amino acids in nhemba cowpeas, and the average increase was 3.4 percentage units. The TMEn of raw nhemba cowpeas was significantly increased (2,806 vs 3,347 kcal/kg DM) by roasting and the TMEn of raw black-eyed cowpeas was significantly increased by extrusion (3,164 vs 3,535 kcal/kilogram DM).

Potential Protease Inhibitor Isoforms from Pigeonpea againstHelicoverpa armigeraGut Proteases

Ten pigeon pea genotypes (four moderately resistant, three intermediate, two moderately susceptible and one unknown status) were evaluated for their efficacy against bovine trypsin and Helicoverpa armigera (H. armigera) gut proteases. The trypsin inhibitor content in pigeon pea genotypes varied from 147.75 (TIU/g) (AL 201) to 177.85 TIU/g (AL 1495). Sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) of seed extracts revealed different proteins of molecular weight ranging from 15.6 kDa to 98.5 kDa. Using gelatin SDS-PAGE, six different trypsin inhibitors with bovine trypsin were identified and four of them with relative mobility (Rm) 0.39, 0.78, 0.84 and 0.93 were present in all the ten genotypes. Five H. armigera protease inhibitors (PIs) were detected using the gelatin SDS-PAGE. Four of them also inhibited the bovine trypsin. One (35.3 kDa) was specific only for H. armigera gut proteases. Two protease inhibitors (15.6 kDa and 20.1 kDa) were specific for bovine trypsin. However, it appears that it is the unspecific PI with Rm 0.39 (51.5 kDa) and 0.93 (16.6 kDa) which mainly determine the resistance towards H. armigera in pigeonpea.

The influence of soybean genotypes and HTC processing method on trypsin inhibitor activity of soymilk

Kunitz inhibitor (KTI) and Bowman-Birk trypsin inhibitor (BBI) are inhibitors of digestive enzymes in raw soybeans. Due to their antinutritive properties in the active state, their inactivation by heat treatment is commonly used. Soymilk is a turbid and stable colloidal solution, obtained by thermal treatment of soybean. In this study soymilk was made on a pilot-plant scale from six soybean cultivars using hydrothermal cooking (HTC) as the production method. This procedure is significantly different from the traditional one. The aim of this investigation was to evaluate the impact of the HTC processing for soymilk production and different soybean genotypes on trypsin inhibitor content and activity. Obtained soymilk contained BBI in trace amounts, in the BBI-polymeric forms. The BBI monomeric forms were not detected. The soymilk of the investigated soybean genotypes had very similar KTI levels (2.34-2.99%). Results have suggested that the soybean genotype does not have substantial effects on the levels of KTI, as well as on the value of residual trypsin inhibitor activity (rTIA). The total content of TI and rTIA showed a strong dependence (r=0.91; p<0.05). HTC-soymilk rTIA was <20% (7.15-19.89%). These results have indicated that HTC processed soymilk is applicable for human consumption.

Extrusion cooking improves the metabolisable energy of faba beans and the amino acid digestibility in broilers

The study was conducted to investigate the nutritional value of 5 cultivars of Vicia faba L. seeds. The study group included 132 male one-day-old Ross 308 chickens. The birds were randomly assigned to 11 dietary treatments (12 replications in each). Birds were kept in individual cages. Nutrient digestibility was calculated using the difference method. From day 1 to 16, birds received only basal diets. From day 17 to 21, in 10 of the treatments, diets contained faba bean meal in raw or extruded form (Merlin, Olga, Albus, Amulet, Kasztelan) and the basal diet in the ratio 40:60. On days 19 and 20, excreta were individually collected, and then all chickens were sacrificed and ileal digesta were sampled for determination of ileal digestibility. The apparent metabolizable energy (AMEN) of raw faba bean seeds ranged from 8.12 to 12.16MJ/kg; the lowest was determined for the Albus and the highest for the Amulet cultivars. Albus faba bean contained more crude protein (347g/kg DM) than the other cultivars. The lowest concentration of crude protein was determined in cv. Kasztelan (281g/kg DM). The AMEN of faba beans was negatively correlated with their content of oligosaccharides (r=−0.80; P≤0.001), raffinose (r=−0.79; P≤0.001) and phytic P (r=−0.55; P≤0.001). Similar negative correlations were observed with respect to the apparent digestibility of dry matter, starch, crude protein and the ileal amino acid digestibility. Extrusion cooking of faba beans decreased their concentration of NDF, ether extracts, trypsin inhibitor, phytic P and resistant starch as well as total and free sialic acid in digesta (P≤0.05). Extrusion improved the AMEN values of raw faba bean seeds and the nutrient digestibility in broilers (P≤0.05).

Evaluation of anti nutritional factors in fungal fermented cereals

Cereals and legumes are rich in minerals, but the bioavailability of these minerals is usually low due to the presence of anti-nutritional factors, such as phytate, trypsin inhibitors, and tannin. Reductions in the influence of these factors is necessary to derive the full nutritive value of cereals and grains. Penicillium camemberti was grown on millets (kodo millet and proso millet) and legumes (moth beans and cow peas). Fermented grains were analyzed for the influence of anti-nutritional factors. Fermentation reduced the phytic acid content in proso millets. The tannin contents were reduced in both moth beans and cow peas while there were reductions of 38.3% and 74.3% in alkaloid contents in fermented moth beans and cowpeas. The trypsin inhibitor contents also decreased in all legumes and millets after solid state fermentation.

Effect of traditional processing methods on the β-carotene, ascorbic acid and trypsin inhibitor content of orange-fleshed sweet potato for production of amala in Nigeria.

The aim of the work was to study the effect of traditional processing methods on the β-carotene, ascorbic acid and trypsin inhibitor contents of orange-fleshed sweet potato amala. The most common sweet potato in Nigeria is white or yellow fleshed, which is very low in provitamin A. However, efforts are underway to promote orange-fleshed sweet potato to improve provitamin A intake. This paper describes how orange-fleshed sweet potato slices were traditionally processed into amala, which is increasingly consumed in Nigeria. The study revealed that both the cold and hot fermentation methods resulted in increased vitamin A levels and lower vitamin C levels in orange-fleshed sweet potato. Further processing to make amala resulted in a fall in both vitamin A and C content. The study found an increase in trypsin inhibitor activity following the cold-water fermentation and a decrease following the hot-water fermentation compared to raw orange-fleshed sweet potato. Trypsin inhibitor activity in amala produced using both the cold and hot methods was below detectable levels. The results indicate that amala produced from traditionally fermented orange-fleshed sweet potato could be a good source of vitamins A and C for the rural poor and that the processing removes any potential negative effects of trypsin inhibitors. © 2015 Society of Chemical Industry.

Tumor-associated trypsin inhibitor in patients with endometrial cancer.

The aim of the study was to look for prognostic factors of metastasis or recurrence in patients with endometrial cancer. Tumor-associated trypsin inhibitor (TATI) concentrations were measured in serum of 317 patients with endometrial cancer. The assay was done 7 times in each patient, from the moment of diagnosis until the start of follow-up after the completion of treatment. Observation of patients after treatment lasted from 0 to 16 years. The TATI levels in patients with adverse prognostic factors accumulated in the first 3 assays and then decreased to zero. Mean TATI concentrations were significantly higher in patients with clinically advanced disease (stage IIIB) than patients at stage I (Kruskal-Wallis p = 0.0446). An increase in the concentration by more than 10.6% in the first 3 assays was significantly correlated with disease relapse (Mann-Whitney Z = -6.06653, p = 0.00000) and local or distant recurrence (Mann-Whitney Z = -4.97475, p = 0.000001). A significant increase in the TATI level in the first 3 tests also occurred in patients who died during the study period (Kruskal Wallis p<0.001). In our series of patients with endometrial cancer, TATI proved to be a sensitive indicator of disease recurrence and distant metastasis, with a sensitivity of 84.4% and 75.7%, respectively. TATI seems to behave as a prognostic factor in certain subgroups of patients with endometrial cancer.

Progress and gaps in understanding mechanisms of ash tree resistance to emerald ash borer, a model for wood-boring insects that kill angiosperms.

We review the literature on host resistance of ash to emerald ash borer (EAB, Agrilus planipennis), an invasive species that causes widespread mortality of ash. Manchurian ash (Fraxinus mandshurica), which coevolved with EAB, is more resistant than evolutionarily naïve North American and European congeners. Manchurian ash was less preferred for adult feeding and oviposition than susceptible hosts, more resistant to larval feeding, had higher constitutive concentrations of bark lignans, coumarins, proline, tyramine and defensive proteins, and was characterized by faster oxidation of phenolics. Consistent with EAB being a secondary colonizer of coevolved hosts, drought stress decreased the resistance of Manchurian ash, but had no effect on constitutive bark phenolics, suggesting that they do not contribute to increased susceptibility in response to drought stress. The induced resistance of North American species to EAB in response to the exogenous application of methyl jasmonate was associated with increased bark concentrations of verbascoside, lignin and/or trypsin inhibitors, which decreased larval survival and/or growth in bioassays. This finding suggests that these inherently susceptible species possess latent defenses that are not induced naturally by larval colonization, perhaps because they fail to recognize larval cues or respond quickly enough. Finally, we propose future research directions that would address some critical knowledge gaps.

Organic grass pea (Lathyrus sativus L.) seeds as a protein source for weaned piglets: Effects of seed treatment and different inclusion rates on animal performance

AbstractOrganically produced pork occupies only a small niche in the European meat market, with one of the main reasons being the shortage of locally produced high-quality protein sources. In an effort to promote currently under-utilized protein sources, two feeding trials were conducted with grass pea seeds as feed for weaned piglets. The grass pea (Lathyrus sativus L.) is a hardy grain legume that produces protein-rich seeds, but, as other grain legumes, it contains several anti-nutritive compounds. Apart from trypsin inhibitors and tannins, it also contains the neurotoxin β-N-oxalyl-L-α,β-diaminopropionic acid (ODAP) which may cause nerve damage in farm animals as well as humans. The content of both trypsin inhibitors and ODAP can be greatly reduced by hydrothermal treatment; therefore both raw and hydrothermally treated grass pea seeds were used in the two feeding trials. Diets were fed to 152 and 144 piglets [crosses of (Pietrain × Duroc) × (Landrace × Large White)] respectively, during their rearing phase directly after weaning. In experiment 1, a control diet was compared with two diets containing 10 and 20% raw grass pea seeds, plus one diet with 20% treated grass pea seeds, respectively (as fed basis). In experiment 2, a control diet was compared with one diet containing 20% raw grass pea seeds and two diets containing 20 and 30% treated grass pea seeds, respectively (as fed basis). Grass pea seeds contained 265 and 271 g kg−1 crude protein (as fed basis) in the first and second experiment, respectively, and had an amino acid profile similar to peas (Pisum sativum), including relatively low contents of methionine and cysteine. Hydrothermally treated grass pea seeds were found to be a valuable protein source that was well accepted by piglets. At an inclusion rate of 20–30% in diets, feed intake and daily weight gain of piglets was very similar to that of the control treatment. However, including 20% raw grass pea seeds had a significant negative effect on feed intake in experiment 1 and on daily weight gain in experiment 2. Therefore, hydrothermal treatment of grass pea seeds is recommended prior to feeding to piglets.

Geographic structure of chemical variation in wild populations of the fuel crop Jatropha curcas L. in Mexico

Jatropha curcas L. (Euphorbiaceae) is a shrub that produces seeds with a high oil content that can be converted to biodiesel. Some studies have shown that this plant contains phytochemicals that cause adverse effects on herbivores; however, it is not known whether the phytochemical variation is geographically structured and, in turn, if it is associated with herbivory intensity. This knowledge would enable the selection of individuals with adequate chemical variation to decrease the herbivory of this plant. With this objective, total foliar content of saponins, trypsin inhibitors, phytic acids, and phenols were analyzed and herbivory quantified in eight wild populations of J. curcas in Chiapas, Michoacán, and Veracruz, Mexico. Using principal components analysis (PCA), the content of phenols, saponins, trypsin inhibitors, and phytic acids grouped individuals to their state or frequently to their population. A multiple linear regression model considering total phytochemical content, altitude and precipitation, explained herbivory intensity (multiple adjusted R2=0.62). The concentration of trypsin inhibitors (par. corr.=0.51, P<0.0001) and altitude (par. corr.=0.769, P<0.0001) were positively associated with herbivory, whereas the concentration of phytic acid (par. corr.=−0.299, P<0.019) and precipitation (par. corr.=−0.503, P<0.0001) were negatively associated. It can be concluded that phytochemical variation is structured geographically at the local level and that herbivory intensity is associated with the total phytochemical content, precipitation, and altitude.

Characterization of individual proteins in pea protein isolates and air classified samples

Generally, pea proteins are extracted at comparatively acidic or basic pH values to provide a basis for protein isolate production. Such processing steps result in partial denaturation of the proteins rendering them in most cases insoluble at food processing pH conditions and limiting their application in food products. Here, the comparison of the solubility properties of pea proteins in protein enriched fractions deriving from air classification is reported. Protein content, solubility, and physicochemical parameters of different fractions of the pea (Pisum sativum) variety ‘Salamanca’ were investigated as a function of pH using SDS-PAGE and surface hydrophobicity. Whole pea flour (20% protein), air classified, protein-enriched pea flour (48% protein), pea flour made from hulls (2.8% protein), and pea protein isolate (81% protein) served as test materials. Fractionation and pH value affected the composition and surface hydrophobicity of the proteins as well as the content of trypsin inhibitors. All samples showed a high buffering capacity in the range of pH4 to 10. The direct comparison documents the comparatively better protein quality of the air classified, protein enriched pea fraction. The solubility of the pea protein isolate can be improved by using selected additives, giving new possibilities for plant protein application. Relevant technofunctional properties were determined and compared with two commercially available pea-based products (whole pea flour and an isolate). Water binding capacity was highest for the commercially available pea flour followed by the pea hull flour. Fat binding capacity remained more or less unchanged.

The ultrasound-treated soybean seeds improve edibility and nutritional quality of soybean sprouts

Limited data are available concerning the physical and nutrient properties of soybean sprouts from the ultrasound-treated seeds. In this study, soybean seeds were treated by ultrasound at different power levels (0W to 300W), then germinated for 5d in darkness. Morphological changes, protein patterns, amino acid contents, gamma-aminobutyric acid (GABA) content, IgE-binding, lipoxygenase isozyme activity, trypsin inhibitor, and isoflavone content of soybean sprouts were quantified. Results showed that ultrasound treatment increased germination rate, sprout length, and GABA content of soybean sprouts. No significant change was observed in protein patterns. The IgE-binding, lipoxygenase isozyme activity, and trypsin inhibitor content of soybean sprouts showed a power-dependent decrease after the seeds were exposed to ultrasound. As for the isoflavone content, daidzin and genstin contents markedly decreased, whereas, daidzein and genistein contents increased compared with those of the untreated sample. The present work indicated that ultrasound treatment will be a novel approach to improve the edibility and nutritional quality of soybean sprouts.

Genetic variability and effect of heat treatment on trypsin inhibitor content in soybean [Glycine max(L.) Merrill.

Kunitz trypsin inhibitor (KTI), a major anti-nutritional factor present in soybean seed, is a major bottleneck in industrial use of soybean and public acceptance of soybean food products. Biochemical screening for trypsin inhibitor content was carried out in 145 genotypes of soybean comprising exotic collections and released varieties. The trypsin inhibitor content ranged from 14.15 to 186.27 mg g-1 of seed meal. Lowest level of trypsin inhibitor content was observed in genotype PI542044, (14.15 mg g-1 seed meal). Popular Indian soybean varieties viz., JS335, JS9305, NRC37, NRC7, PK1225, DS9712, JS9752, and DS9814 contained higher level of trypsin inhibitor. Heat treatment was able to reduce the TI content but to certain level leaving about 20% residual activity. The study indicated the need for other ways to create genotypes with reduced KTI for use in breeding program.

Biochemical screening for trypsin inhibitor factors and morphomolecular characterization of soybean (Glycine maxL. Merr.)

A set of 101 diverse soybean genotypes were biochemically analyzed for trypsin inhibitor (TI) contents, and were characterized with morphological and molecular markers. The TI content in the seeds ranged from 14.65 to 175.52 mg g−1 soymeal. The Indian soybean varieties were found to contain higher amount of TI (58.79–126.78 mg g−1 soymeal) while PI542044, an exotic germplasm was found to contain the least (14.65 mg g−1 soymeal). Morphological characterization with 16 qualitative and quantitative traits revealed significant variations and grouped the genotypes in to three major groups with overall mean dissimilarity value of 0.30. Genetic diversity study conducted with 100 simple sequence repeat (SSR) markers detected higher level of polymorphism (71%). Of the total 221 alleles amplified, 65 were rare (frequency <0.2). The mean polymorphism information content (PIC) of the markers was 0.27 while the value for gene diversity was 0.44. UPGMA-based cluster analysis grouped the genotypes into four major clusters of which I, II and III were occupied by genotypes containing higher and moderate level of TI. PI542044, which was free from Kunitz trypsin inhibitor (KTI), grouped singly. Such genotype would be suitable for use in breeding program directed towards development of varieties with zero KTI.