A Novel and Rapid Colorimetric Method for Measuring Total Phosphorus and Phytic Acid in Foods and Animal Feeds.
McKie, V. A. & McCleary, B. V. (2016). J. AOAC Int. , 99(3), 738-743.
Phytic acid, or myo-inositol hexakisphosphate, is the primary source of inositol and storage phosphorus in plant seeds and has considerable nutritional importance. In this form, phosphorus is unavailable for absorption by monogastric animals, and the strong chelating characteristic of phytic acid reduces the bioavailability of multivalent minerals such as iron, zinc, and calcium. Currently, there is no simple quantitative method for phytic acid; existing methods are complex, and the most commonly accepted method, AOAC Official MethodSM 986.11, has limitations. The aim of this work was to develop and validate a simple, high-throughput method for the measurement of total phosphorus and phytic acid in foods and animal feeds. The method described here involves acid extraction of phytic acid, followed by dephosphorylation with phytase and alkaline phosphatase. The phosphate released from phytic acid is measured using a modified colorimetric molybdenum blue assay and calculated as total phosphorus or phytic acid content of the original sample. The method was validated to a maximum linearity of 3.0 g phytic acid/100 g sample. Accuracy ranged from 98 to 105% using pure phytic acid and from 97 to 115% for spiked samples. Repeatability ranged from 0.81 to 2.32%, and intermediate precision was 2.27%.
High hydrostatic pressure influences antinutritional factors and in vitro protein digestibility of split peas and whole white beans.
Linsberger-Martin, G., Weiglhofer, K., Thi Phuong, T. P. & Berghofer, E. (2013). LWT-Food Science and Technology, 51(1), 331-336.
Legumes are of high nutritional value but consumption is low in Western countries due to long processing and antinutritional factors. The development of convenience products can help to overcome these constraints. The present study investigated the effect of high hydrostatic pressure on oligosaccharides, phytic acid and total phenolic acid content, trypsin inhibitor activity and protein digestibility in peas and beans. Oligosaccharides were significantly reduced through pressurisation by up to 68% in peas and 48% in beans but reduction was lower than in cooked samples (max. 82% in peas and 80% in beans). Phytic acid was reduced by high pressure by up to 36% in peas and 11% in beans. Total phenolic acid content was reduced only in some pressurised peas and beans as compared to untreated peas and beans. Reduction of phytic acid (max. 48%) and total phenolic acids (max. 78%) through cooking was greater than through pressurisation. Trypsin inhibitor activity decreased by up to 100% in peas and 84% in beans during pressurisation. Protein digestibility increased by up to 4.3% in peas when treated at 600 MPa and 60°C regardless of time and by 8.7% in beans treated at 600 MPa at 60°C for 60 min.
The influence of germination conditions on beta-glucan, dietary fibre and phytate during the germination of oats and barley.
Hübner, F., O’Neil, T., Cashman, K. D. & Arendt, E. K. (2010). European Food Research and Technology, 231(1), 27-35.
This study aimed to quantify the changes caused by varying germination conditions on the contents of some bioactive compounds in barley and oats. Samples of the two grains were germinated at temperatures between 10 and 20°C for a period of 2–6 days, using a two-dimensional central composite design. The germination temperature had only minor effect in comparison with the germination time. Slight changes in the mineral content of the malts were observed, mainly caused by steeping. Phytate has been seen as an anti-nutritional compound, as it complexes minerals and lowers their bioavailability. The phytate content in barley malts was considerably lower than in the native kernels. Variations in the germination conditions did not have a significant effect on phytate content. In oats, degradation of phytate was significantly enhanced by prolonging the germination period. It was possible to retain the amounts of soluble dietary fibre, when short germination periods were applied. However, long germination periods caused an extensive breakdown of soluble dietary fibre, especially beta-glucan. The content of insoluble fibre, however, was increased by applying long germination periods for oat malts.
Measurement of true ileal digestibility and total tract retention of phosphorus in corn and canola meal for broiler chickens.
Mutucumarana, R. K., Ravindran, V., Ravindran, G. & Cowieson, A. J. (2014). Poultry Science, 93(2), 412-419.
The study reported herein was conducted to determine and compare the nonphytate P, digestible P, and retainable P contents of corn and canola meal for broiler chickens. Four semipurified diets were formulated from each of ingredient to contain graded concentrations of nonphytate P. The experiment was conducted as a randomized complete block design with 4 weight blocks of 8 cages each (6 birds per cage). A total of 192 broilers (Ross 308), 21 d old, were assigned to the 8 test diets. Ileal digestibility and total tract retention coefficients of P were determined by the indicator and total collection methods, respectively, and linear regression method was used to determine the true P digestibility and true P retention coefficients. The apparent ileal digestibility of P in corn was influenced (quadratic, P< 0.05) by increasing dietary nonphytate P concentrations, whereas P retention was unaffected (P> 0.05). The apparent ileal P digestibility in broilers fed diets based on canola meal was similar (P> 0.05) at different P concentrations. Phosphorus retention in broilers fed diets based on canola meal (linear, P< 0.01) decreased with increasing P concentrations. True ileal P digestibility and true P retention coefficients of corn were determined to be 0.676 and 0.632, respectively. The corresponding values for canola meal were 0.469 and 0.486, respectively. In both ingredients, the determined true ileal digestibility and total tract retention coefficients were not different (P> 0.05). Total P, nonphytate P, true digestible P, and true retainable P contents of corn were determined to be 2.5, 0.8, 1.7, and 1.6 g/kg (as received), respectively. The corresponding values for canola meal were 9.7, 2.8, 4.6, and 4.7 g/kg (as received), respectively. The present data demonstrated that the regression method can be successfully used to measure true P digestibility of low and high P feed ingredients and that both true ileal digestibility and retention coefficients are suitable to assess P availability in broilers.
Micronisation and hot air roasting of cowpeas as pretreatments to control the development of hard‐to‐cook phenomenon.
Ndungu, K. E., Emmambux, M. N. & Minnaar, A. (2012). Journal of the Science of Food and Agriculture, 92(6), 1194-1200.
Background: Cowpeas stored under conditions of high temperature and high relative humidity (HTHH) develop the hard-to-cook (HTC) defect. Cowpeas with HTC defect require long cooking times, limiting their utilisation. Heat pretreatments are aimed at inactivating the enzymes responsible for HTC defect development. In this study, two heat pretreatments, micronisation and hot air roasting, were evaluated to assess their effectiveness in controlling the HTC defect development in cowpeas after storage under HTHH conditions. Results: Micronisation and hot air roasting as pretreatments reduced the cooking time of cowpeas after storage under HTHH conditions compared with the control. The differences in the effectiveness of HTC defect control between micronisation and roasting were dependent on the degree of phytase inactivation on day 0. Phytase activity was reduced by 45 and 70% by roasting and micronisation pretreatments respectively. Reduced phytase activity was associated with higher phytate and soluble pectin contents in micronised cowpeas than in roasted cowpeas after HTHH storage. This observation is in agreement with the phytase-phytate-pectin theory. Conclusion: Micronisation was more effective than hot air roasting in controlling the development of HTC defect. This was due to a higher degree of phytase inactivation in micronisation when compared with roasting.
Starch properties, in vitro digestibility and sensory evaluation of fresh egg pasta produced from oat, teff and wheat flour.
Hager, A. S., Czerny, M., Bez, J., Zannini, E. & Arendt, E. K. (2013). Journal of Cereal Science, 58(1), 156-163.
Specific dietary requirements, e.g. ceoliac disease, as well as increased consumer demand for products of high nutritional value, makes the production of pasta from alternative cereals interesting. Raw material characterisation showed that the utilisation of oat and teff flour is beneficial as these ingredients contain higher levels of fibre and mineral composition is superior to that of wheat. Starch properties significantly influence pasta quality and therefore damaged starch levels, amylase activity, pasting properties and gelatinisation temperatures of the flours were investigated. Fresh egg pasta based on wheat, oat and teff flour was produced. Sensory properties of oat spaghetti were found to be very close to that of wheat pasta but improvement of smoothness and aroma is necessary, while teff spaghetti showed reduced sensory quality. An in vitro enzymatic digestion was performed using a dialysis system to mimic the behaviour of pasta as eaten and make predictions on the glycemic index (GI). The predicted GI was highest for wheat pasta, followed by teff and oat. Ultra structure was studied using confocal laser scanning microscopy, allowing the visualisation of differences in starch granule size and shape as well as gelatinisation occurring during the cooking process.
Influence of decortication, popping and malting on bioaccessibility of calcium, iron and zinc in finger millet.
Krishnan, R., Dharmaraj, U. & Malleshi, N. G. (2012). LWT-Food Science and Technology, 48(2), 169-174.
Finger millet is a rich source of calcium and other minerals. The presence of high amounts of phytates, polyphenols and dietary fibre, may lower the bioaccessibility of minerals. The present study was aimed to determine the influence of decortication, popping and malting on bioaccessibility of calcium, iron and zinc in finger millet. The seed coat fraction of the millet was also included in the studies. Bioaccessibility of minerals was estimated by equilibrium dialysis method while phytic acid by colorimetric method. Polyphenols and dietary fibre were estimated by Folin–Ciocalteu and enzymatic methods respectively. Decortication decreased the total mineral contents, but increased the bioaccessibility of calcium, iron and zinc by 15, 26 and 24 g/100 g respectively. Popping decreased the bioaccessible calcium by about 10 g/100 g and increased that of iron by 5 and 14 g/100 g respectively in native and decorticated millet. No significant increase in bioaccessibility of zinc was observed on popping the decorticated millet but native millet showed an increase of 18 g/100 g. Malted millet showed higher values of bioaccessibility for all the minerals while seed coat fractions exhibited comparatively lower values, because of high proportion of inhibitory factors. Total phytic acid, polyphenols and dietary fibre decreased significantly on decortication and malting.
Comparative study of colorectal health related compounds in different types of bread: Analysis of bread samples pre and post digestion in a batch fermentation model of the human intestine.
Hiller, B., Schlörmann, W., Glei, M. & Lindhauer, M. G. (2011). Food Chemistry, 125(4), 1202-1212.
Seven different types of wheat and rye bread were analysed for colorectal health related compounds, pre and post digestion, in batch fermentation model of the human intestine. Pre digestion, higher amounts of colorectal health-related dietary fibre compounds (soluble/insoluble/total dietary fibre, arabinoxylans, β-glucans) and phytochemicals (mono-/di-phenolic acids, phytic acid, hydroxymethylfurfural) were detected in wholemeal than in refined flour types of bread, as well as in rye flour types than in wheat flour types of bread. Post digestion, faecal bacterial metabolites of colorectal health promoting (acetate/propionate/butyrate, lactate, free mono-/di-phenolic acids) and impairing (amino metabolites, bile acid metabolites) activities were found in fermentation supernatants of bread samples. All types of bread positively affected faecal bacterial metabolism; among the different types of bread, the highest stimulation of organic acid production (acetate/propionate/butyrate, lactate) and the lowest detrimental bacterial enzyme activities (β-glucuronidase, urease) were detected for wheat flour bread, whereas the strongest retardation of bacterial bile acid degradation and the strongest stimulation of phenolic acid metabolite release (phenylpropionic/phenylpropenoic acid derivatives) were induced by wholemeal rye bread. This study for the first time presents a qualitative and quantitative overview over the broad spectrum of colorectal health related compounds in high- and low-fibre types of bread, pre and post in vitro digestion, and highlights the significance of bread for the preventive nutritional intervention of colorectal cancer.
Changes in carbohydrates, proteins and lipids of finger millet after hydrothermal processing.
Dharmaraj, U. & Malleshi, N. G. (2011). LWT-Food Science and Technology, 44(7), 1636-1642.
Finger millet was soaked, steamed and dried to prepare hydrothermally processed millet, followed by decortication to prepare decorticated millet. The physicochemical properties and carbohydrate, protein and lipid profiles of control and processed millet were determined. The carbohydrates were fractionated to amlypectin and amylose equivalent fractions using gel permeation chromatography. The non-starch polysaccharides were isolated and their alditol acetyl derivatives were characterized by gas chromatography (GC). The proteins were extracted using different solvents and the total proteins were fractionated using SDS-PAGE. The ether extractable lipids were esterified and fractionated through GC. Hydrothermal processing decreased the amylopectin fraction and increased the amylose equivalent portion of the starch. Decortication further lowered the first fraction and increased the second fraction. A decrease in cold, hot water soluble and hemicellulose-B fractions and an increase in pectic polysaccharides, hemicellulose-A and cellulosic fractions were observed as a result of hydrothermal processing. Decortication significantly reduced the total non-starch polysaccharides specifically the cellulose fraction. Hydrothermal processing decreased the overall extractability of proteins by 50% but decortication increased it to 80%. It was observed that hydrothermal treatment did not change the gross nutrients composition of finger millet but for their profile. Decortication of hydrothermally processed millet caused significant changes in the nutrient contents and also in their profiles.
Distribution and speciation of iron and zinc in grain of two wheat genotypes.
Eagling, T., Neal, A. L., McGrath, S. P., Fairweather-Tait, S., Shewry, P. R. & Zhao, F. J. (2014). Journal of Agricultural and Food Chemistry, 62(3), 708-716.
This study aimed to determine differences among wheat cultivars in the distribution and speciation of Fe and Zn in grain milling fractions. Cultivars with higher Fe and Zn concentrations in the wholemeal flour were found to contain higher concentrations in the white flour. Soluble Fe and Zn were extracted and analyzed by size exclusion–inductively coupled plasma mass spectrometry. Fe speciation varied between milling fractions with a low molecular weight (LMW) complex likely to be Fe–deoxymugenic acid/nicotianamine being the predominant extractable Fe species in white flour, accounting for approximately 85% of the extractable Fe. Bran fractions had a lower amount of LMW-Fe form but more as soluble Fe–phytate and an unidentified high molecular weight peak. In the white flour fraction soluble Zn was found to be present mainly as a LMW peak likely to be Zn–nicotianamine complex. Soluble Fe–phytate was found in the white flour fraction of a high-Fe cultivar but not in a low-Fe cultivar.
Differential expression of structural genes for the late phase of phytic acid biosynthesis in developing seeds of wheat (Triticum aestivum L.).
Bhati, K. K., Aggarwal, S., Sharma, S., Mantri, S., Singh, S. P., Bhalla, S., Kaur, J., Tiwari, S., Roy, J. K., Tuli, R. & Pandey, A. K. (2014). Plant Science, 224, 74-85.
In cereals, phytic acid (PA) or inositol hexakisphosphate (IP6) is a well-known phosphate storage compound as well as major chelator of important micronutrients (iron, zinc, calcium, etc.). Genes involved in the late phases of PA biosynthesis pathway are well-known in crops like maize, soybeans and barley but none have been reported from wheat. Our in silico analysis identified six wheat genes that might be involved in the biosynthesis of inositol phosphates. Four of the genes were inositol tetraphosphate kinases (TaITPK1, TaITPK2, TaITPK3, and TaITPK4), and the other two genes encode for inositol triphosphate kinase (TaIPK2) and inositol pentakisphosphate kinase (TaIPK1). Additionally, we identified a homolog of Zmlpa-1, an ABCC subclass multidrug resistance-associated transporter protein (TaMRP3) that is putatively involved in PA transport. Analyses of the mRNA expression levels of these seven genes showed that they are differentially expressed during seed development, and that some are preferentially expressed in aleurone tissue. These results suggest selective roles during PA biosynthesis, and that both lipid-independent and -dependent pathways are active in developing wheat grains. TaIPK1 and TaMRP3 were able to complement the yeast ScΔipk1 and ScΔycf1 mutants, respectively, providing evidence that the wheat genes have the expected biochemical functions. This is the first comprehensive study of the wheat genes involved in the late phase of PA biosynthesis. Knowledge generated from these studies could be utilized to develop strategies for generating low phyate wheat.
Effect of Fermentation by Probiotic Lactobacillus acidophilus NCDC 13 on Nutritional Profile of a Dairy-cereal based Composite Substrate.
Ganguly, S., Sathish Kumar, M. H., Singh, A. K. & Sabikhi, L. (2014). J Food Nutr Disor, S1-002. doi:10.4172/2324-9323. S1-002.
The current study was aimed at evaluating the effects of fermentation on the nutritional profile of a composite dairy-cereal substrate. The organism (Lactobacillus acidophilus NCDC 13, a dairy isolate probiotic strain) had a biomass concentration 1012/ml in MRS medium and was starch hydrolysis-negative and phytasepositive with a phytase activity of 0.705 unit/ h/ ml. A composite dairy-cereal substrate consisting of whey-skim milk – (60:40 w/w), germinated pearl millet flour (5% w/v) and liquid barley malt extract (3% w/v) was heat processed (95°C /5 min), inoculated using different inoculum levels of L. acidophilus NCDC 13 and incubated at 37°C for different periods, up to a maximum of 8 h. A high count of probiotic organisms was observed in the substrate, to a maximum of 13.22 log cfu/ml at 4% inoculum level and 8 h incubation. Phytic acid, polyphenol contents and phytate phosporous reduced by 80.0, 47.2 and 76.5% respectively, as a result of probiotic fermentation. The protein and starch digestibility increased respectively from 45.4 and 43.4% to a maximum of 62.4 and 57.8%, at 4% inoculums level and 8 h incubation. Under the same fermentation conditions, bio-availability of Ca and Fe increased by 69.0 and 64.0%. The investigation demonstrated that probiotic fermentation resulted in beneficial nutritional changes comprising of reduced antinutrients content and enhanced nutritional availability in the dairy-cereal substrate.
Phytic acid in green leaves of herbaceous plants–Temporal variation in situ and response to different N/P fertilizing regimes.
Alkarawi, H. H. & Zotz, G. (2014). AoB Plants, plu048, 1-20.
Phytic acid is the major storage compound for phosphorus (P) in plants. While accounting for up to 90% in many seeds, only usually <10% of total P is found in phytic acid in green leaves. This study follows up on the findings of a recent review of the occurrence of phytic acid in green leaves which revealed 1) that the current knowledge of phytic acid in leaves is mostly based on data from (fertilized) crop plants and 2) that the proportion of total P in phytic acid seems to decrease with improved P status in leaves in contrast to an increase in seeds and fruit. We studied five species of wild herbaceous plants in the field and under controlled conditions. Foliar P concentrations were much lower than those of the crops of earlier studies, but the proportion of P in phytic acid was similar, with little variation during the observation period. Both the field data and the experimental data showed a statistically indistinguishable negative correlation of phytic acid P/total P and total P. In contrast to our expectation, this negative relationship was not related to differences in relative growth rates. We conclude 1) that our data of phytic acid concentrations in leaves of wild plants are in line with earlier observations on crops, and 2) that the trend towards lower proportions of phytic acid-P with increasing P status is probably a general phenomenon. Currently lacking a convincing explanation for the second observation, the role of phytic acid in foliar P metabolism is still unclear.
Influence of gamma rays and ethyl methane sulphonate (EMS) on the levels of phytic acid, raffinose family oligosaccharides and antioxidants in soybean seeds of different genotypes.
Kumar, A., Kumar, V., Lal, S. K., Jolly, M. & Sachdev, A. (2015). Journal of Plant Biochemistry and Biotechnology, 24(2), 204-209.
Soybean seeds accumulate raffinosaccharides (RFOs) and phytic acid throughout development and maturation. Efforts are being made to produce soybean varieties containing lower phytic acid and raffinose but higher antioxidant contents. Thus, in the present study, influence of irradiation (0.20–0.25 kGy) and EMS (0.1 %) was studied on the phytic acid, RFOs and antioxidant contents in 136 irradiated lines from 34 bulked mutant populations of soybean. Among these lines, four populations showed low levels of phytic acid and RFOs but high levels of antioxidants as compared to their unirradiated controls. These were selected and grown in pot house in order to eliminate the influence of growing locations with widely differing soil types on phytic acid content. The results indicated that all four mutant populations showed good seedling emergence; while two of them viz. IR-JS-101 (0.25 KGy) and IR-DS-122 (0.20 KGy) harbouring the desired combination of phytic acid, RFOs and antioxidant could thus be more beneficial for both food and also for feed purpose.
Comparative characterization of foxtail millet, physico-chemical approach for its suitability to celiacs.
Singh, A. & Hathan, B. S. (2014). Journal of Food Processing and Technology, 5(11).
This investigation Focused on comparative physico-chemical characterization of Foxtail millet in the form of pearling and germination and the changes evaluated with raw grains and staple cereals as well. Proximate outcomes showed no marked differences after treatments. These pre-treatments resulted in 58% and 83% reduction in total polyphenols, 43% and 53% reduction in phytic acid for germinated and pearled flour respectively. Calcium, Iron and Zinc content lies at 24.1 mg/g, 4.2227 mg/g and 1.0499 mg/g respectively in germinated grains, which decreased to 18.88 mg/g, 2.5504 mg/g and 0.4635 mg/g after pearling. Observations for comparable antioxidant capacity of bran depict its nutraceutical characteristics. Lowering of peak viscosity value from 46.20 cP for pearled to 4.17 cP for germinated proves its suitability for bakery consideration. Results from the above investigation can be a basis to consume it as staple diet.
Application of bioprocessing techniques (sourdough fermentation and technological aids) for brewer's spent grain breads.
Ktenioudaki, A., Alvarez-Jubete, L., Smyth, T. J., Kilcawley, K., Rai, D. K. & Gallagher, E. (2015). Food Research International, 73, 107-116.
A comprehensive study into the potential of bioprocessing techniques (sourdough fermentation and technological aids) for improving the technological, sensory, and nutritional properties of breads made using brewer's spent grain (BSG) was undertaken. Xylanase and dough conditioner altered the mixing and pasting properties of the flours, improved the specific volume and texture of breads and delayed staling in BSG breads when added to both sourdough and non-sourdough BSG breads. The aromatic properties were determined by volatile analysis and were influenced by sourdough fermentation. Ferulic and 4-coumaric acids were the main phenolic acids found in insoluble bound form in BSG flour, while the phenolic profile was different for the free extracts. Sourdough fermentation and the use of enzymes increased the antioxidant capacity of breads.
Chlorogenic acid-arabinose hybrid domains in coffee melanoidins: Evidences from a model system.
Moreira, A. S., Coimbra, M. A., Nunes, F. M., Passos, C. P., Santos, S. A., Silvestre, A. J., Silva, A. M. N., Rangel, M., Domingues, M. R. M. & Domingues, M. R. M. (2015). Food Chemistry, 185, 135-144.
Arabinose from arabinogalactan side chains was hypothesized as a possible binding site for chlorogenic acids in coffee melanoidins. To investigate this hypothesis, a mixture of 5-O-caffeoylquinic acid (5-CQA), the most abundant chlorogenic acid in green coffee beans, and (&alpha1 &rarr 5)-L-arabinotriose, structurally related to arabinogalactan side chains, was submitted to dry thermal treatments. The compounds formed during thermal processing were identified by electrospray ionization mass spectrometry (ESI-MS) and characterized by tandem MS (ESI-MSn). Compounds composed by one or two CQAs covalently linked with pentose (Pent) residues (1-12) were identified, along with compounds bearing a sugar moiety but composed exclusively by the quinic or caffeic acid moiety of CQAs. The presence of isomers was demonstrated by liquid chromatography online coupled to ESI-MS and ESI-MSn. Pent1-2CQA were identified in coffee samples. These results give evidence for a diversity of chlorogenic acid-arabinose hybrids formed during roasting, opening new perspectives for their identification in melanoidin structures.
Contribution of intestinal-and cereal-derived phytase activity on phytate degradation in young broilers.
Morgan, N. K., Walk, C. L., Bedford, M. R. & Burton, E. J. (2015). Poultry Science, 94(7), 1577-1583.
There is little consensus as to the capability of poultry to utilize dietary phytate without supplemental phytase. Therefore, an experiment was conducted to examine the extent to which endogenous phytase of intestinal and cereal origin contributes to phytate degradation in birds aged 0 to 14 d posthatch. Ross 308 broilers (n = 720) were fed one of 4 experimental diets with differing dietary ingredient combinations and approximate total phytate levels of 10 g/kg, dietary phytase activity analyzed at 460 U/kg, dietary calcium (Ca) levels of 11 g/kg, and nonphytate-phosphorus (P) levels of 4 g/kg. Broiler performance, gizzard, duodenum, jejunum and ileum pH, Ca and P digestibility and solubility, amount of dietary phytate hydrolyzed in the gizzard, jejunum, and ileal digesta phytase activity were analyzed at d 4, 6, 8, 10, 12, and 14 posthatch. Intestinal endogenous phytase activity increased significantly (P < 0.001) between d 4 and 6, resulting in increased phytate hydrolysis in the gizzard (P = 0.003), jejunum (P < 0.001), and ileum (P < 0.001). Phytase activity and phytate hydrolysis continued to increase with age, with a greater phytase activity and associated increase in phytate hydrolysis and mineral utilization between d 10 and 12. Gizzard and jejunum Ca and P solubility and ileal Ca and P digestibility increased significantly (P < 0.001), and gastrointestinal pH decreased significantly (P < 0.001) between d 4 and 6. By d 14, phytase activity recovered in the ileum was approximately 45 U/kg. There were strong correlations between phytase activity measured in the ileum and phytate hydrolyzed in the gizzard (r = 0.905, P < 0.001), jejunum (r = 0.901, P = 0.023), and ileum (r = 0.938, P = 0.042). This study shows intestinal- and dietary-derived endogenous phytase activity is responsible for phytate-P hydrolysis in broilers.
In vitro versus in situ evaluation of the effect of phytase supplementation on calcium and phosphorus solubility in soya bean and rapeseed meal broiler diets.
Morgan, N. K., Walk, C. L., Bedford, M. R. & Burton, E. J. (2014). British Poultry Science, 55(2), 238-245.
1. In vitro assays provide a rapid and economical tool to evaluate dietary effects, but have limitations. In this study, the effect of phytase supplementation on solubility, and presumed availability, of calcium (Ca) and phosphorus (P) in soya bean meal (SBM) and rapeseed meal (RSM) based diets were evaluated both in situ and by a two-step in vitro digestion assay that simulated the gastric and small intestine (SI) phases of digestion. 2. Comparison of the in vitro findings to in situ findings was used to evaluate the in vitro assay. Ross 308 broilers (n = 192) were fed on one of 6 SBM or RSM diets supplemented with 0, 500 or 5000 FTU/kg phytase from 0 to 28 d post hatch. The 6 diets and raw SBM and RSM were exposed to a two-step in vitro assay. Ca and P solubility and pH in the gizzard and jejunal digesta and in the gastric and SI phase of in vitro digestion were measured. 3. Both in vitro and in situ analyses detected that Ca solubility was lowest when diets were supplemented with 500 FTU/kg phytase, compared to the control diets and diets supplemented with 5000 FTU/kg phytase. Phosphorus solubility increased with increasing phytase level. Both methods also identified that mineral solubility plateaus in the gastric phase. 4. Overall relationship of the two methods was strong for both determination of gastric phase Ca and P solubility (r = 0.96 and 0.92, respectively) and also SI phase Ca and P solubility (r = 0.71 and 0.82, respectively). However, mineral solubility and pH were higher when measured in vitro than in situ, and the in situ assay identified an interaction among the effects of phase, protein source and phytase inclusion level on Ca solubility that the in vitro assay did not detect. 5. This two-step in vitro assay successfully predicted phytase efficacy, but to determine detailed response effects in the animal, in situ data is still required.
Low gamma irradiation effects on protein profile, solubility, oxidation, scavenger ability and bioavailability of essential minerals in black and yellow Indian soybean (Glycine max L.) varieties.
Krishnan, V., Singh, A., Thimmegowda, V., Singh, B., Dahuja, A., Rai, R. D. & Sachdev, A. (2016). Journal of Radioanalytical and Nuclear Chemistry, 307(1), 49-57.
Effect of low doses of gamma irradiation (0.25, 0.5 and 1.0 kGy) on protein oxidation, profile, solubility, ROS scavenging and in vivo bioavailability of minerals in black (BS1) and yellow (BRAGG) soybean varieties were investigated. Increased oxidation, altered protein profile with decreased solubility was observed higher in BRAGG compared with BS1. The most significant ROS scavenging effect, antioxidant activity, least phytate content and improved bioavailability was found at 0.5 kGy in BS1 than BRAGG due to anthocyanins, and phenolics. Still 1.0 kGy is considered as toxicologically and microbiologically safe but it causes biochemical alterations and thus 0.5 kGy can be the optimum dose with enriched nutraceutical properties.