The protective role of phytate in the oxidative degradation of cereal beta-glucans

Wang, Yujie; Zhan, Ruzhen; Sontag‐Strohm, Tuula; Maina, Ndegwa Henry

doi:10.1016/j.carbpol.2017.04.016

Cited by 11 publications

(6 citation statements)

References 23 publications

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“…Although there is an abundance of literature about iron bioavailability in foods, only few studies investigate or discuss the role of the partly soluble dietary fibers such as β-glucan ( 24 , 25 , 40 , 65 ). However, it is nowadays an established fact that phytic acid plays a major role in the observed reduced bioavailability of the iron present in cereals and other vegetable food, as also confirmed by Wang et al ( 10 , 11 ). As previously discussed, both oat and barley β-glucan extracts contain high levels of phytic acid ( Table 2 ) and it is well known that even small amounts of phytic acid can bind considerable amounts of iron ( 9 , 46 ).…”

Section: Resultsmentioning

confidence: 62%

“…The phytic acid content of the oat and barley β-glucan extracts before and after Chelex treatment was determined in triplicates with the Phytic Acid (Phytate)/Total Phosphorus Kit obtained from Megazyme, Ireland ( 11 ). The samples were incubated with phytase and alkaline phosphatase to release inorganic phosphate (P i ) from phytic acid.…”

Section: Methodsmentioning

confidence: 99%

“…Also, there is considerable evidence that phytic acid, which is associated with fibers in many foods, reduces the bioavailability of iron ( 6 – 9 ). In particular, recent studies have confirmed phytic acid as the main responsible for iron-binding by commercial oat and barley β-glucan preparations ( 10 , 11 ). During food processing, such as baking, sourdough fermentation, heating in aqueous systems, or high-pressure homogenisation, in fact, β-glucan can undergo degradation, e.g., chain scission and oxidation ( 12 – 14 ), which can alter its behaviour in the gastro-intestinal tract, and which can, in turn, affect the equilibrium between phytic acid and iron.…”

Section: Introductionmentioning

confidence: 96%

“…On the other hand, Fenton-induced oxidation of three constitutionally isomeric β-glucan tetrasaccharides as model compounds with no or one β-(1 → 3)-linkage exhibited no significant differences in degradation kinetics, suggesting that for the commercial β-glucan polymer materials, other constituents than the pure carbohydrates were responsible for the difference in behaviour between the oat and barley β-glucan materials ( 26 ). Wang et al ( 10 , 11 ) attributed the differences in iron-binding behaviour of commercial β-glucan materials to the varying levels of residual phytic acid, as removal of phytic acid by treatment with ion-exchange resins led to same degradation rates and iron-binding capacities of all β-glucan materials irrespective of their origin.…”

Section: Introductionmentioning

confidence: 99%

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Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model

et al. 2022

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For cereal-based foods rich in dietary fibers, iron bioavailability is known to be poor. For native cereal β-glucan extracts, literature has demonstrated that the main factor impacting the bioavailability is phytic acid, which is often found in association with dietary fibers. During food processing, β-glucan can undergo modifications which could potentially affect the equilibrium between phytic acid, fiber, and iron. In this study, an in vitro digestion was used to elucidate the iron dialysability, and hence estimate iron availability, in the presence of native, chelating resin (Chelex)-treated, oxidised, or partially hydrolysed oat and barley β-glucan extracts (at 1% actual β-glucan concentration), with or without phytase treatment. It was confirmed that pure, phytic acid-free β-glucan polysaccharide does not impede iron availability in cereal foods, while phytic acid, and to a smaller extent, also proteins, associated to β-glucan can do so. Neither Chelex-treatment nor partial hydrolysis, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or NaIO4 oxidation significantly influenced the phytic acid content of the β-glucan extracts (ranging 2.0–3.9%; p > 0.05). Consequently, as long as intrinsic phytic acid was still present, the β-glucan extracts blocked the iron availability regardless of source (oat, barley) or Chelex-treatment, partial hydrolysis or NaIO4-oxidation down to 0–8% (relative to the reference without β-glucan extract). Remarkably, TEMPO-oxidation released around 50% of the sequestered iron despite unchanged phytic acid levels in the modified extract. We propose an iron-mobilising effect of the TEMPO product β-polyglucuronan from insoluble Fe(II)/phytate/protein aggregates to soluble Fe(II)/bile salt units that can cross the dialysis membrane. In addition, Chelex-treatment was identified as prerequisite for phytase to dramatically diminish iron retention of the extract for virtually full availability, with implications for optimal iron bioavailability in cereal foods.

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Section: Resultsmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model

et al. 2022

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“…Oat and barley β-glucan (OBG & BBG) were oxidized by an iron-catalyzed (50 μM FeSO 4 ), HO • -mediated degradation, either mildly with an ascorbate-driven Fenton reaction (250 μM AH 2 ), or harshly with Fenton-induced oxidation using H 2 O 2 directly (100 mM). To minimize factors that influence the degradation such as potential iron (Faure et al, 2013a ) and phytic acid contaminations (Faure et al, 2012 ; Wang et al, 2017 ), commercial high viscosity OBG & BBG (>97%) were first dialyzed against EDTA and H 2 O. The oxidized β-glucans were then subjected to four sample preparation strategies I–IV and UPLC-MS/MS analysis (section Part 1—Methodology), which revealed their product profile dependence on β-glucan source (oat vs. barley) and reaction conditions (AH 2 vs. H 2 O 2 ) (section Part 2—Application).…”

Section: Resultsmentioning

confidence: 99%

Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS

Boulos

Nyström

2017

Front. Chem.

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The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO•) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO•-attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO•-attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be (1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and (2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan's health promoting and technological properties.

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Red grape skin extract and oat β-glucan in shortbread cookies: technological and nutritional evaluation

Szpicer

Onopiuk

Wojtasik‐Kalinowska

et al. 2021

Eur Food Res Technol

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Consumers are increasingly interested in innovative products enriched with nutrients that counteract the development of civilisation-associated diseases. Thus, the development of new functional nutrient-enriched food products that meet consumer needs is therefore necessary. The aims of this study were to develop a novel shortbread cookie product by addition of red grape skin extract and oat β-glucan and to evaluate the influence of these modifications on physico‐chemical properties and consumer’s acceptance. The red grape skin extract used in this product is a source of polyphenols which are beneficial for human health and extend product shelf life. β-glucan is a soluble fraction of dietary fibre that helps to lower reduce blood cholesterol and glycemic levels. The influence of grape skin extract, β-glucan and a combination of both on the β-glucan content, colour and texture parameters, thermal properties, total antioxidant activity, total phenolic content, volatile compounds profile and sensory properties of shortbread cookies was analysed. Product with modified formulations had higher total antioxidant activity, total phenolic content and were was more thermally stable than control samples. The obtained innovative functional products were characterized by an increased content of oat β-glucan, which is desirable from a nutritional point of view. The DSC measurements showed higher oxidative stability of cookies enriched with β-glucan and red grape skin extract. The additives caused significant changes in the colour and profile of volatile compounds of the finished final product but did not affect the sensory acceptance among consumers. The use of these additives represents a development in food technology that may be valuable in the food industry to increase the nutritional value and extend the shelf shelf-life of bakery products.

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The protective role of phytate in the oxidative degradation of cereal beta-glucans

Cited by 11 publications

References 23 publications

Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model

Estimation of Iron Availability in Modified Cereal β-Glucan Extracts by an in vitro Digestion Model

Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS

Red grape skin extract and oat β-glucan in shortbread cookies: technological and nutritional evaluation

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