Mineral Bioaccessibility Research Articles

Probiotic Potential, Iron and Zinc Bioaccessibility, and Sensory Quality of Uapaca kirkiana Fruit Jam Fermented with Lactobacillus rhamnosus Yoba.

Uapaca kirkiana is an underutilised indigenous fruit tree (IFT) found in the miombo ecological zone in sub-Saharan Africa. Furthermore, sub-Saharan Africa is home to many nutritionally insecure people who suffer from micronutrient deficiency. The incorporation of probiotic strains in jams as a possible way of enhancing mineral accessibility, food quality, and health is limited in Africa. This study monitored the probiotic potential, bioaccessible iron and zinc, and organoleptic properties of U. kirkiana fruit jam fermented with L. rhamnosus yoba. U. kirkiana fruits were collected from semiarid rural areas of Zimbabwe. The L. rhamnosus yoba strain was obtained from the Yoba for Life Foundation, Netherlands. Mineral and biochemical properties of the probiotic jam were analysed using AOAC standard methods. The U. kirkiana fruit tree was ranked first as a food resource by most rural populations in Zimbabwe. The probiotic jam formulation had 55% (wt/vol) U. kirkiana fruit pulp, 43% (wt/vol) sugar, 1.25% (wt/vol) pectin, 0.5% (wt/vol) citric acid, and 0.25% (wt/vol) L. rhamnosus yoba strain. The probiotic jam had 6.2 ± 0.2 log CFU/mL viable L. rhamnosus yoba cells. Iron and zinc content (mg/100 g w.b.) was 4.13 ± 0.22 and 0.68 ± 0.02 with pH 3.45 ± 0.11, respectively. Nutrient content was g/100 g w.b., carbohydrate 66 ± 4.1, fat 0.1 ± 0.01, crude protein 0.2 ± 0.01, ash 0.7 ± 0.02, and crude fiber 0.3 ± 0.01. Bioaccessible iron and zinc were 6.55 ± 0.36% and 16.1 ± 0.50% and increased by 4% and 2% in the probiotic jam, respectively. Mineral bioaccessibility and nutrient content were significantly different (p < 0.05) in jam with 0.25% L. rhamnosus yoba. Jam acceptance rating was 83%. The probiotic jam can be used as a sustainable food containing probiotic with potential nutritional and health benefits.

Interactions Between Phytochemicals and Minerals in Terminalia ferdinandiana and Implications for Mineral Bioavailability.

Oxalic and phytic acid are phytochemicals considered to be anti-nutritional factors as they are predominantly found as oxalates and phytates bound to minerals like calcium and potassium. Studies have associated excessive oxalate consumption with increased urinary excretion of oxalate (hyperoxaluria) and calcium oxalate kidney stone formation, and excessive phytate consumption with decreased bioaccessibility and bioavailability of certain minerals and reduced utilization of dietary protein. However, other studies suggest that dietary consumption of phytate may be beneficial and inhibit formation of calcium oxalate kidney stones. In light of these conflicting reports, dietary intake of oxalate and phytate enriched plants should be considered in relation to potential health outcomes following consumption. Terminalia ferdinandiana is one such plant and is investigated here with respect to oxalate, phytate, and mineral contents. Assessment of oxalate and phytate contents in T. ferdinandiana fruit, leaf, and seedcoat tissues through hydrolysis into acid forms revealed oxalic acid contents ranging from 327 to 1,420 mg/100 g on a dry weight (DW) basis whilst phytic acid contents ranged from 8.44 to 121.72 mg/100 g DW. Calcium content in the different tissues ranged from 131 to 1,343 mg/100 g. There was no correlation between oxalic acid and calcium, however a significant, positive correlation was observed between phytic acid and calcium (r = 0.9917; p < 0.001), indicating that tissues rich in phytic acid also contain higher levels of calcium. The high content of phytic acid in comparison to oxalic acid in T. ferdinandiana fruit found in this study and the dietary significance of this in terms of calcium bioavailability, needs to be investigated further.

Opportunities for plant-derived enhancers for iron, zinc, and calcium bioavailability: A review.

Understanding of the mechanism of interactions between dietary elements, their salts, and complexing/binding ligands is vital to manage both deficiency and toxicity associated with essential element bioavailability. Numerous mineral ligands are found in both animal and plant foods and are known to exert bioactivity via element chelation resulting in modulation of antioxidant capacity or micobiome metabolism among other physiological outcomes. However, little is explored in the context of dietary mineral ligands and element bioavailability enhancement, particularly with respect to ligands from plant-derived food sources. This review highlights a novel perspective to consider various plant macro/micronutrients as prospective bioavailability enhancing ligands of three essential elements (Fe, Zn, and Ca). We also delineate the molecular mechanisms of the ligand-binding interactions underlying mineral bioaccessibility at the luminal level. We conclude that despite current understandings of some of the structure-activity relationships associated with strong mineral-ligand binding, the physiological links between ligands as element carriers and uptake at targeted sites throughout the gastrointestinal (GI) tract still require more research. The binding behavior of potential ligands in the human diet should be further elucidated and validated using pharmacokinetic approaches and GI models.

Pectin and phytic acid reduce mineral bioaccessibility in cooked common bean cotyledons regardless of cell wall integrity

Common bean cotyledons are rich in minerals (Mg, Ca, Fe and Zn), but they also contain natural barriers that can potentially prevent mineral absorption during digestion. In this study, both the cell wall integrity and mineral chelators/antinutrients (phytic acid and pectin) were investigated as natural barriers in common bean cotyledons. To examine the cell wall integrity as a physical barrier for mineral diffusion, soluble mineral content was determined in a cooked cotyledon sample before and after disruption of intact cell walls. While this study showed that the cell wall in cooked common bean cotyledons does not hinder mineral diffusion, it also demonstrated that the presence of antinutrients decreases mineral bioaccessibility. It was shown that a certain mineral fraction is naturally bound to phytic acid and/or pectin and, by enzymatically degrading these antinutrients, the antinutrient-chelated mineral fraction decreased. Moreover, although pH changes are occurring during simulated digestion experiments, which might affect charge of the antinutrients and thus their chelating capacity for minerals, no difference in mineral distribution over antinutrients was observed due to digestion. In addition, this study showed that mineral bioaccessibility in common bean cotyledons could be potentially increased by degrading antinutrients during digestion in the small intestinal phase.

Processing of four different cooking methods of Oudemansiella radicata: Effects on in vitro bioaccessibility of nutrients and antioxidant activity

The purpose of this study is to evaluate the bioaccessibility of nutrients and antioxidant activity of O. radicata after subjecting to four types of domestic cooking and followed by in vitro digestion. The result demonstrated that the group with the lowest amino acid release and the degree of protein hydrolysis (5.6%) was frying, but both reducing sugar content and antioxidant activity were the highest. The composition of fatty acids was different than undigested samples, especially the relative content of linolenic acid was significantly decreased (e.g., 34.49 to 8.23%, boiled). The difference of the minerals bioaccessibility was slightly affected by the cooking method, but mainly related to their natural properties, such as the highest phosphorus (62.73%) and the lowest iron (21.53%) in the steaming. The above data provides a starting point for the design of processes at an industrial and gastronomic level.

Impact of soaking, germination, fermentation, and thermal processing on the bioaccessibility of trace minerals from food grains

The effects of soaking, germination, fermentation, and thermal processing on the bioaccessible copper (Cu), manganese (Mn), and chromium (Cr) from selected food grains as well as from some chiefly consumed food products—idli, dosa, and dhokla were investigated. Soaking of the legumes (chickpea and green gram) and cereal–pulse combinations (rice + black gram) used for idli and dosa preparation, improved the bioaccessible Cr; however, the bioaccessible Cu and Mn were reduced. Germination improved the Cu and Cr bioaccessibility. Fermentation enhanced only the Cr bioaccessibility in idli and dosa batter. Also, cooking enhanced only the bioaccessible Cu in idli and dosa. The beneficial effects of these processing methods were more visible in Cr bioaccessibility, followed by Cu. The present study can be helpful in understanding the effects of household methods on the bioaccessibility of less understood minerals (Cu, Mn, and Cr), and thus, in developing dietary strategies. Practical applications Copper (Cu), manganese (Mn), and chromium (Cr) are the essential trace minerals required by humans for normal physiological functions. Cereals and pulses are the primary sources of these minerals. However, the bioavailabilities of these minerals from plant foods are compromised due to the presence of several antinutrients such as phytates, polyphenols, oxalates, etc. Household methods such as soaking, germination, fermentation, and thermal processing are known to affect the bioavailability of minerals both positively and negatively. However, the information on the effect of these food processing methods on Cu, Mn, and Cr is poorly documented. In this study, we reported the beneficial effect of germination and thermal processing on bioaccessible Cu, and, soaking, germination, and fermentation on bioaccessible Cr from food grains. Thus, we can recommend using these household methods to access the plant foods with higher bioavailability of essential trace minerals, Cu and Cr.

Influence of various ingredients on mineral bioaccessibility in infant formula and whole milk

The mineral composition and bioaccessible fraction of different types of infant formula and milk samples were evaluated. Mineral content was higher in the infant formula than in the milk samples by 162, 63, 37 and 2-fold for Fe, Cu, Mn and Zn, respectively. The mineral bioaccessibility in milk products was found to be influenced by both the total content and the type of processing (pasteurised, powdered or UHT). For milk-based formulas, the addition of a prebiotic generally improved the dialysability of K, Fe, Mg, Cu and Zn, whereas the enzymatically hydrolysed protein had no effect on the bioaccessibility of most of the elements. Infant formulas containing soy protein showed results for dialysability similar to those for formulas containing whey protein. In general, infant formula results indicated that the high mineral absorption could be related to the protein type, presence of prebiotics and mineral concentrations.

Dephytinising efficacy of wheat phytase in enhancing the bioaccessibility of minerals in high phytate foods

Iron deficiency anemia and zinc deficiency are major public health problems in developing world which are attributable to the poor bioavailability due to the presence of phytic acid in plant foods. Dephytinisation by enzymatic application is identified to be ideal approach, however the commercial availability of phytases from food sources is scarce. This prompted us to undertake the investigation on the dephytinisation of the high phytate food matrices by utilising the indigenous phytase of wheat. Attempts were made to enhance the phytase activity by various approaches. Phytase activity of wheat was increased by fivefold on sprouting (96 h). The native phytase of wheat activated by incubation at optimum conditions of pH and temperature has shown an increase in the activity as a function of time. Isolation and partial purification of phytase from sprouted wheat further increased the activity by 1.5 fold. Thermostability of phytase was enhanced by additives such as sodium citrate, calcium chloride and magnesium sulphate. Addition of phytase activated wheat flour to soya flour enhanced the bioaccessible iron by 1.7 fold. Partially purified phytase enhanced the bioaccessible iron by 1.9 fold and zinc by 2.4 fold in defatted soya flour reflecting dephytinisation. Investigation on complete purification of phytase are warranted.

Influence of addition of β-carotene rich vegetables and acidulants on the bioaccessibility of trace minerals from selected cereals and pulses

This study aimed at evaluating the effect of β-carotene rich vegetables and acidulants on the copper (Cu), manganese (Mn), and chromium (Cr) bioaccessibility from selected cereals (rice and sorghum) and pulses (green gram and chickpea). The assessment of the possible effect of β-carotene on minerals bioaccessibility was done by adding two levels of carrot and amaranth (2.5 and 5 g) to 10 g of selected grain. The amounts of acidulants added to the grains were at the level that produced a pH decrease by 1 unit. The bioaccessible minerals were estimated by employing an in vitro gastrointestinal digestion procedure in both raw and cooked grains. The enhanced bioaccessible Cu, Mn, and Cr in the cooked grains, as a result of the addition of carrot and amaranth, was in the range of 17–52%, 24–270%, and 17–71%, respectively. A significant increase in Cu, Mn, and Cr bioaccessibility from food grains was also observed in the presence of acidulants, and the increase was from 42 to 169%, 69–164%, and 59–100%, respectively. Thus, we observed the beneficial effect of β-carotene and acidulants on the bioaccessibility of these minerals. This information on the effect of exogenous components on the bioaccessibility of Cu, Cr and Mn is novel, and finds usefulness in evolving dietary strategies to improve the intake of these important trace minerals.

Effect of Buckwheat Groats Processing on the Content and Bioaccessibility of Selected Minerals.

Adequate supply of minerals in the diet is necessary for the proper functioning of the human body. In recent years gluten-free diet, which rigorous forms may lead to deficiencies of mineral components (especially Mg, Mn, Zn and Cu), is becoming more and more popular. Buckwheat grains do not contain gluten, and their nutritional value is very high. They are often consumed in the form of groats, which are obtained from roasted and dehulled seeds. The purpose of the work was to determine how conducting the buckwheat groats production in industrial conditions affects the content and availability of magnesium, manganese, zinc and copper. The results indicated that husk removal had a particularly adverse effect on the total manganese content and its amount released by enzymatic digestion, whereas it had a positive effect on the post-digestion zinc level by increasing it by nearly half. Hydrothermal processes especially affected the release of analysed elements simulated by the in vitro method, and the extent of changes depended on the processing parameters. It was shown that bioaccessibility of minerals may be increased by treating buckwheat at a lower temperature for a short time, which has a particularly beneficial effect on the manganese and magnesium. Treating grains at a higher temperature reduces the bioaccessibility of all analysed elements, which was particularly noted for zinc and copper. Based on the obtained results, it should be stated that buckwheat groats should be a regular part of human diet, because they are a good source of easily digestible mineral compounds. Their consumption should be especially considered by people on a rigorous gluten-free diet, as they can prevent mineral deficiencies associated with its use.

Food to food fortification of breads and biscuits with herbs, spices, millets and oilseeds on bio-accessibility of calcium, iron and zinc and impact of proteins, fat and phenolics

The study evaluated substituting refined wheat flour (RWF) with malted finger-millet, oilseeds, spices and herbs to improve Ca, Fe and Zn and its bio-accessibility in breads and biscuits. Proteins, fat and phenolics as factors of mineral bio-accessibility were also studied. Ingredients and products like breads viz. RWF (C1); sesame, cumin, moringa (T1), sesame, finger-millet (T2) and sesame (T3); biscuits viz. RWF (C2), soy-butter salty (T4) and soy-butter sweet (T5) were analyzed for total and bio-accessible Ca, Fe and Zn, protein, fat and phenolics. T1 contained highest total and bio-accessible calcium (276 and 197 mg/100g) and total and bio-accessible iron (4.5 and 3.2 mg/100g). T4 contained highest total and bio-accessible zinc (3.1 and 2.2 mg/100g). Both T1 and T4 contained dried moringa leaves (1321 mg calcium, 4.7 mg iron in 100g), good amounts of protein and lower content of phenolics compared to other test products. Consuming 50g of T1 or 100g of T4 takes care of nearly 1/2 of the RDA of calcium, 1/4 of the RDA for iron and 1/6 of the RDA for zinc for children (7–9 y). Enriched breads and biscuits were good sources of bio-accessible minerals and could contribute in improving mineral profiles of diets.

Characterization of Micronutrients, Bioaccessibility and Antioxidant Activity of Prickly Pear Cladodes as Functional Ingredient.

The Opuntia ficus indica (L.) (OFI) is used as a nutritional and pharmaceutical agent in various dietary and value added products. This study underlines the possible use of native prickly pear cladode powder as a functional ingredient for health-promoting food production. To summarise, chemical characterization of polyphenols, minerals and soluble dietary fibre was performed; furthermore, the antioxidant activity and bioaccessibility of polyphenols and minerals were assessed. Eleven compounds between phenolic acids and flavonoids were identified, with piscidic acid and isorhamnetin derivatives being the most abundant. Opuntia’s dietary fibre was mainly constituted of mucilage and pectin, and was composed of arabinose, galactose, glucose, mannose, rhamnose, and xylose sugars. The polyphenols’ bioaccessibility was very high: piscidic acid at 200%, eucomic and ferulic acids >110% and flavonoids from 89% to 100%. The prickly pear cladode powder is also a source of minerals, as cations (calcium, sodium, potassium and magnesium) and anions (sulphate and chloride), with high magnesium bioaccessibilty (93%). OFI powder showed good capacity of radical scavenging measured by DPPH and ABTS methods, with 740 and 775 μmol Trolox/100 g OFI, respectively. Finally, the presented results allow the consideration of this natural product as a source of several essential nutrients, with a possible use in the food industry as a functional ingredient.

Evaluation of fatty acid and mineral profiles and bioaccessibility of diosgenin in different types of Peruvian maca (Lepidium meyenii Walp)

The present work aimed to study the bioaccessibility of diosgenin, fatty acid and mineral profile in different types of Peruvian maca (Lepidium meyenii Walp). Analyzes of minerals, fatty acids, saponins and bioaccessibility of diosgenin were performed. For minerals the values were detected: commercial litter (MC) 490.65mg / 100g of Ca, 1472.65mg / 100g of K, in red litter (MV) 1478.25mg / 100g of K and 670.25mg / 100g of Ca, yellow yellow (MA) 875.65mg / 100g Ca, 1215.25mg / 100g K. The highest concentrations of fatty acids were related to the unsaturated portion. % oleic acid in the red stretcher. Regarding the saponin and diosgenin content, the commercial litter presented the highest contents 250.33mg / 100g for saponins, and 340.56µg / ml for diosgenin. These results emphasize the importance of the consumption of this nutrient-rich vegetable with effective action on human metabolism (p &lt;0.05).

Effect of phytase treatment of sorghum flour, an alternative for gluten free foods and bioaccessibility of essential minerals.

This study evaluated the effect of phytase treatment on the bioavailability of iron (Fe), calcium (Ca), zinc (Zn), and myo-inositol phosphate fractions in sorghum flour; and characterized its macronutrients and minerals. The proximate composition and mineral content indicated that, sorghum flour has a nutritional potential superior to wheat and maize. The results obtained in the solubility and dialysis assays indicated that, naturally occurring minerals (without phytase treatment) in sorghum flour, presented considerable bioaccessibility; reaching 32, 47 and 67% of dialyzable Fe, Zn, and Ca respectively. The use of phytase had a positive influence on the reduction of myo-inositol phosphates, mainly the IP6 fraction, present in sorghum flour samples, and an increase in the soluble percentage (Fe 52% for one sample, for Zn higher than 266%) and dialyzed minerals (Fe 7.8-150%; Zn 19.7 for one sample; and Ca 5-205%) for most samples. Therefore, the essential minerals naturally occurring in sorghum have an absorption potential; and the use of phytase reduced the IP6 fraction and improved the availability of the minerals evaluated.

Mineral Composition and Bioaccessibility in Asteracantha longifolia (L.) Nees

Asteracantha longifolia (L.) Nees . (AL) a small, spiny weed found in marshy places. It is reported for its “antitumor, hypoglycemic, aphrodisiac, antibacterial, free radical scavenging and lipid peroxidation, hepatoprotective activities”3 . Accompanying its uses for a medicinal purpose the plant is also used as a leafy vegetable in some states of India. Hence study of mineral composition of Asteracantha longifolia (L.) Nees and its bioaccessibility is crucial along with studying phytoconstituents of this plant. Nutritional food value of the plant can be accessed by in-vitro gastrointestinal simulation in the form of Bioaccessible Fraction (BF). The bioaccessibility of minerals found in the plant is not investigated thoroughly, mainly in functional foods. Therefore, in this research work we have subjected shade-dried powdered material of AL to ICP-AES qualitative and quantitative analysis. The results revels presence of the essential elements like Calcium (Ca) at 814.5 ppm with %BF 96.5, Magnesium (Mg) at 169.2 ppm with %BF 102.8 and micronutrients like Iron (Fe) at 5.3 ppm with %BF of 25.0, Manganese (Mn) at 4.1 ppm with %BF 100.9 and Zinc (Zn) at 0.6 ppm with %BF 31.6. Successively based on the findings it is concluded that AL has good nutritional value.

PDO Rotonda’s Red Eggplant Extract: In vitro Determination of Biological Properties and Minerals Bioaccessibility

Background: The Rotonda’s Red Eggplant belongs to the family of Solanum aethiopicum and it is cultivated in a specific area of Potenza (Basilicata, South of Italy) including villages of Rotonda, Viggianello, Castelluccio Superiore and Castelluccio Inferiore. The Red Eggplant cultivated in this area has gained the PDO, “Protected Designation of Origin”. Objective: The aim of this research was to evaluate the use of PDO Rotonda’s Red Eggplant extract as a possible nutraceutical supplement. The antioxidant, antihypertensive, hypoglycemic, and hypolipidemic properties were in vitro evaluated. Methods: The antioxidant activity was investigated by evaluating the scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and by performing the Ammonium Molybdate and Folin-Ciocalteu assay. The hypoglycemic and antihypertensive activity was studied by evaluating the α-Amylase, α-Glucosidase and Angiotensin Converting Enzyme, respectively, inhibiting activity. In order to evaluate the hypolipidemic activity, the pancreatic lipase inhibiting property was determined and Oil Red O staining assay was performed. Finally, to evaluate the possible use of this extract as a minerals supplement, Selenium, Potassium and Chrome bioaccessibility was studied. Results: The obtained results underline the good antioxidant, hypoglycemic, antihypertensive and hypolipidemic in vitro properties of the PDO Rotonda’s Red Eggplant extract. Moreover, the obtained data show a higher minerals bioaccessibility and this higher value could be ascribable to the natural phytocomplex of PDO Rotonda’s Red Eggplant, which increases the minerals bioaccessibility if compare it with a control sample. Conclusion: The obtained results show that PDO Rotonda’s Red Eggplant extract, might be used as a possible nutraceutical supplement, along with traditional therapies, both for its biological properties and for its minerals bioaccessibility value.

In vitro digestion effect on mineral bioaccessibility and antioxidant bioactive compounds of plant-based beverages.

Consumption of plant-based beverages (PBB) is a growing trend; and have been used as viable substitutes for dairy based products. To date, no study has comparatively analyzed mineral composition and effect of in vitro digestion on the bioaccessibility of different PBB. The aim of this research was to investigate the content of essential minerals (calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn)) and to estimate the effect of in vitro digestion in plant-based beverages, and their antioxidant bioactive compounds (phenolic compounds and antioxidant capacity). Moreover, the presence of antinutritional factors, such as myo-inositol phosphates fractions, were evaluated. Samples of PBB (rice, cashew nut, almond, peanut, coconut, oat, soy, blended or not with another ingredients, fortified with minerals or naturally present) and milk for comparison were evaluated. TPC ranged from 0.2mg GAEq/L for coconut to 12.4mg GAEq/L for rice and, the antioxidant capacity (DPPH) ranged from 3.1 to 306.5µmol TE/L for samples containing peanut and oat, respectively. Only a few samples presented myo-inositol phosphates fractions in their composition, mostly IP5 and IP6, especially cashew nut beverages. Mineral content showed a wide range for Ca, ranging from 10 to 1697.33mg/L for rice and coconut, respectively. The Mg content ranged from 6.29 to 251.23-268.43mg/L for rice and cashew nut beverages, respectively. Fe content ranged from 0.76mg/L to 12.89mg/L for the samples of rice. Zinc content ranged from 0.57mg/L to 8.13mg/L for samples of oat and soy, respectively. Significant variation was observed for Ca (8.2-306.6mg/L) and Mg (1.9-107.4mg/L) dialyzed between the beverages, with lower concentrations of Fe (1.0mg/L) and Zn (0.5mg/L) in dialyzed fractions. This study provides at least 975 analytically determined laboratory results, providing important information for characterization and comparison of different plant-based beverages.

The impact of postharvest storage and cooking time on mineral bioaccessibility in common beans

Mineral (Mg, Ca, Fe and Zn) bioaccessibility in common beans was evaluated taking into consideration the common bean food chain from postharvest storage over processing (soaking and cooking) until consumption. Beans were stored under realistic tropical conditions (35 °C and 80% RH) which resulted in significantly different cooking behaviour after 8 weeks compared to freshly harvested beans. Based on postcooking hardness, different storage times were selected: unstored, 8 and 20 weeks. Independently of storage conditions, beans were soaked overnight and cooked for 30, 60 or 120 min. The mineral bioaccessibility decreased with increase in both storage and cooking times. Decrease in mineral bioaccessibility with increasing storage time was proved to be the result of increasing mineral chelation of cell wall polymers (e.g. pectin). Additionally, we hypothesize that by cooking, mineral chelators become more accessible, e.g. through pectin solubilization phenomena, in turn capturing more free minerals leading to a reduced mineral bioaccessibility.

Evaluation of the content and bioaccessibility of magnesium, manganese, zinc and copper from buckwheat groats produced in various conditions

AbstractIn recent years special attention has been paid to gluten-free foods, and among them buckwheat grains are becoming more popular. They are a rich source of many nutrients, including mineral compounds, and are eaten in many forms, eg. as a “kasha” which is obtained from roasted and dehulled grains. Food processing causes various changes in chemical composition of raw materials and their rate depends on the treatment parameters, therefore the aim of the study was to determine how the content and bioavailability of selected minerals is influenced by conduction the buckwheat groats production under different conditions.The experimental materials were buckwheat grains subjected in industrial conditions to a short hydrothermal treatment (ca. 100°C/15 min) conducted in cereal dryer (unroasted groats were obtained), and also roasted in pressure boilers (140°C/90 min, 0.4 MPa) to receive roasted grains. The content of selected minerals (Mg, Mn, Zn, Cu) was determined by flame atomic absorption spectrometry and their bioavailability was determined by enzymatic hydrolysis in vitro in a system, which simulated the conditions in the human gastrointestinal tract.It was shown that different conditions of applied hydrothermal treatment had a lesser influence on the total content of analyzed minerals (determined before the digestion process), but they significantly influenced their bioaccessibility. Short treatment carried out at a lower temperature had a beneficial effect on the availability of all determined elements, increasing it to the greatest extent for Mg and Mn.This process caused an increase in the content of Mg released after digestion from 859.4 μg/g (unheated grains) to 1233.8 μg/g (unroasted groats), and the Mn level increased respectively from 2.61 to 5.19 μg/g. The roasting process statistically significantly (p &lt; 0.001) reduced the level of these elements (to 836.1 μg/g for Mg and 1.99 μg/g for Mn). The high parameters of seed treatment used during roasting also caused a decrease in the availability of other elements and their effect was most noticeable for Zn, whose level decreased from 31.99 μg/g (unheated grains) to 9.97 μg/g (roasted groats).Observed dependencies allow to state, that due to the bioaccessibility of minerals, it is more beneficial to treat buckwheat grains with a lower temperature in a short time, and therefore consumers who pay attention to the nutritional value of the food, should choose unroasted buckwheat groats.

Degradation of polysaccharides from Lycium barbarum L. leaves improves bioaccessibility and gastrointestinal transport of endogenous minerals

Acidic heteropolysaccharide (LP) from Lycium barbarum L. leaves has compact globular structure which wrapped abundant endogenous minerals inside by ionic interactions with uronic acid. This study investigated the efficacy of chemical degradation of LP on the bioaccessibility and transport of endogenous minerals in simulated gastrointestinal fluids. Results showed that the degradation using vitamin C and hydrogen peroxide mildly decreased LP molecular weight from 162.0 kDa to 94.3 kDa, and the structure of degraded LP (LPD) was converted to loose coil. After the simulated intestinal digestion, the accessibility of Ca, Fe, Zn, and Mg in LPD increased by119%, 52%, 103% and 112.5% compared with the intact LP, respectively, and in particular, the uptake rate increased by 15.8%, 8.1%, 23.4% and 21.6% for Ca, Fe, Zn, and Mg, respectively. These results demonstrated that the chemical degradation is a helpful strategy to improve the uptake of endogenous minerals wrapped in polysaccharide.