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Liu XC, Wei X, Skibsted LH, Tomasevic I, Yao X, Wang W, Sun W. Investigation of the peptides with calcium chelating capacity in hydrolysate derived from spent hen meat. J Food Sci 2024; 89:2277-2291. [PMID: 38488738 DOI: 10.1111/1750-3841.17023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/17/2024] [Accepted: 02/21/2024] [Indexed: 04/12/2024]
Abstract
Calcium peptide chelates are developed as efficient supplements for preventing calcium deficiency. Spent hen meat (SHM) contains a high percentage of proteins but is generally wasted due to the disadvantages such as hard texture. We chose the underutilized SHM to produce peptides to bind calcium by proteolysis and aimed to investigate chelation between calcium and peptides in hydrolysate for a sustainable purpose. The optimized proteolysis conditions calculated from the result of response surface methodology for two-step hydrolysis were 0.30% (wenzyme/wmeat) for papain with a hydrolysis time of 3.5 h and 0.18% (wenzyme/wmeat) for flavourzyme with a hydrolysis time of 2.8 h. The enzymatic hydrolysate (EH) showed a binding capacity of 63.8 ± 1.8 mg calcium/g protein. Ethanol separation for EH improved the capacity up to a higher value of 68.6 ± 0.6 mg calcium/g protein with a high association constant of 420 M-1 (25°C) indicating high stability. The separated fraction with a higher amount of Glu, Asp, Lys, and Arg had higher calcium-binding capacity, which was related to the number of ─COOH and ─NH2 groups in peptide side chains according to the result from amino acid analysis and Fourier transform infrared spectroscopy. Two-step enzymatic hydrolysis and ethanol separation were an efficient combination to produce peptide mixtures derived from SHM with high calcium-binding capacity. The high percentage of hydrophilic amino acids in the separated fraction was concluded to increase calcium-binding capacity. This work provides foundations for increasing spent hen utilization and developing calcium peptide chelates based on underutilized meat.
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Liu XC, Skibsted LH. Citrate in calcium transport and biomineralisation. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2022.105561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Wang J, Munk MB, Skibsted LH, Ahrné LM. Impact of pectin and whey minerals solubilized by lime juice on calcium bioaccessibility in yogurt based snacks. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.107817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Liu XC, Liu J, Skibsted LH. Temperature effect on calcium binding to aspartate and glutamate. Food Res Int 2022; 159:111625. [DOI: 10.1016/j.foodres.2022.111625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/30/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022]
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Nielsen EN, Skibsted LH, Yazdi SR, Merkel A, Ahrné LM. Improving electrodialysis separation efficiency of minerals from acid whey by nano‐filtration pre‐processing. INT J DAIRY TECHNOL 2022. [DOI: 10.1111/1471-0307.12893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Song MT, Wang WZ, Lu Y, Han RM, Skibsted LH, Zhang JP. Double-Site Binding and Anti-/Pro-oxidation of Luteolin on Bovine Serum Albumin Mediated by Copper(II) Coordination. ACS OMEGA 2022; 7:19521-19534. [PMID: 35721975 PMCID: PMC9202249 DOI: 10.1021/acsomega.2c01226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The interactions of luteolin (Lut) with bovine serum albumin (BSA) mediated by Cu(II) were investigated by spectroscopic, calorimetric, and molecular dynamic (MD) methods. Fluorescence studies showed that the binding of Lut to BSA was significantly enhanced by Cu(II) coordination with the number of binding sites and binding constant increasing from n = 1 and K a = 3.2 × 105 L·mol-1 for Lut to n = 2 and K a = 7.1 × 105 L·mol-1 for a 1:1 Cu(II)-luteolin complex, in agreement with the results from isothermal titration calorimetry (ITC). Site-specific experiments with warfarin and ibuprofen and MD confirmed that two binding sites of BSA were sequentially occupied by two Cu(II)-luteolin complexes. Cu(II) coordination increased the antioxidant activity of luteolin by 60% in the inhibition of carbonyl formation from the oxidation of amino groups in the side chain of BSA induced by the peroxyl radical ROO•; however, it counteracted the antioxidant effects of luteolin and played pro-oxidative roles in BSA aggregation induced by •OH.
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Fan KK, Zhou YM, Wei Y, Han RM, Wang P, Skibsted LH, Zhang JP. Peroxyl radical induced membrane instability of giant unilamellar vesicles and anti-lipooxidation protection. Biophys Chem 2022; 285:106807. [DOI: 10.1016/j.bpc.2022.106807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/07/2022] [Accepted: 03/20/2022] [Indexed: 11/02/2022]
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Olsen K, Orlien V, Skibsted LH. Pressure denaturation of β-lactoglobulin: volume changes for genetic A and B variants. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2022.105416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Christiansen MV, Dave A, Skibsted LH, Ahrné L. Functional properties of skim milk concentrates produced by reverse osmosis filtration and reconstituted commercial powders. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2021.105225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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de Zawadzki A, Liu XC, Ahrné LM, Skibsted LH. Increasing calcium phosphate aqueous solubility and spontaneous supersaturation combining citrate and gluconate with perspectives for functional foods. Food Chem 2021; 374:131701. [PMID: 34902813 DOI: 10.1016/j.foodchem.2021.131701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/16/2021] [Accepted: 11/25/2021] [Indexed: 12/20/2022]
Abstract
Uptake of calcium from food depends on solubility of calcium salts in the intestines, and precipitation of calcium phosphates decreases bioaccessibility of food calcium. Citrate as a high affinity complex binder for calcium was found spontaneously to create strongly supersaturated solutions by rapid dissolution of calcium hydrogen phosphate characterized by short lag phases for precipitation. Gluconate with weaker affinity for calcium binding showed longer lag phases for precipitation from supersaturated solutions. For citrate/gluconate combinations, the highest degree of supersaturation with longest lag phases for precipitation were found by trial-and-error experiments for a citrate/gluconate ratio of 1:10 for dissolution of calcium hydrogen phosphate resulting in supersaturation factors around three and without precipitation for more than a month. The aim of the present study was to provide a physicochemical explanation of this robust supersaturation. Calcium speciation based on electrochemical calcium activity measurement identified a low [Ca2+]·[HCitr2-] product as critical for supersaturation.
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Liu C, Wang W, Song M, Lu Y, Qian L, Han R, Skibsted LH, Zhang J. Corrigendum: Radical Scavenging Efficiency of Flavonoids Increased by Calcium(II) Binding: Structure‐Activity Relationship. ChemistrySelect 2021. [DOI: 10.1002/slct.202103267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Jiang Y, Liu XC, Ahrné LM, Skibsted LH. Enthalpy-entropy compensation in calcium binding to acid-base forms of glycine tyrosine dipeptides from hydrolysis of α-lactalbumin. Food Res Int 2021; 149:110714. [PMID: 34600648 DOI: 10.1016/j.foodres.2021.110714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/02/2021] [Accepted: 09/10/2021] [Indexed: 11/27/2022]
Abstract
Calcium binding to peptides formed by hydrolysis of whey proteins during digestion is important for calcium uptake in the intestines and affects the antioxidant function of the peptides. For the two dipeptides, Gly-Tyr and Tyr-Gly, potential hydrolysis products of α-lactalbumin, calcium binding to the three forms of each dipeptide in acid-base equilibrium at intestinal pH was determined electrochemically and compared to binding to tyrosine for aqueous 0.16 M NaCl for 5 < pH < 9 at 15 °C, 25 °C, and 37 °C. At milk pH at 25 °C, binding of calcium to the zwitterion of GlyTyr dominates, with an association constant Kass2 = 22 M-1 with ΔH0 = -46 kJ·mol-1, while binding to the mononegative TyrGly dominates for TyrGly with Kass3 = 32 M-1 and ΔH0 = -38 kJ·mol-1. At intestinal conditions, pH = 7 and 37 °C, binding of calcium has similar affinity for GlyTyr and TyrGly, while at higher pH and lower temperature, GlyTyr binds stronger. Density Functional Theory calculations confirmed a stronger binding to the zwitterion of GlyTyr than of TyrGly and an increasing affinity with increasing pH for both. Calcium binding to the acid/base forms of the dipeptides is at neutral pH strongly exothermic with ΔH0 becoming less negative at higher pH, and a linear enthalpy-entropy compensation (r2 = 0.99) results in comparable binding important for calcium bioavailability along the changing distribution among acid-base forms. Calcium binding decreases radical scavenging rate and antioxidative activity of both dipeptides.
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Zhou YM, Zhang Y, Gao RY, Liu W, Wei Y, Han RM, Wang P, Zhang JP, Skibsted LH. Primary reaction intermediates of Type-I photosensitized lipid oxidation as revealed by time-resolved optical spectroscopies. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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14
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Liu C, Wang W, Song M, Lu Y, Qian L, Han R, Skibsted LH, Zhang J. Radical Scavenging Efficiency of Flavonoids Increased by Calcium(II) Binding: Structure‐Activity Relationship. ChemistrySelect 2021. [DOI: 10.1002/slct.202101560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Wei Y, Zhou YM, Li YQ, Gao RY, Fu LM, Wang P, Zhang JP, Skibsted LH. Spatial effects of photosensitization on morphology of giant unilamellar vesicles. Biophys Chem 2021; 275:106624. [PMID: 34051444 DOI: 10.1016/j.bpc.2021.106624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 11/28/2022]
Abstract
Singlet oxygen (1O2) formed through photosensitization may initiate oxidative destruction of biomembranes, however, the influence from the spatial organization of photosensitizers (PS) relative to membranes remains unclear. To clarify this issue, we loaded riboflavin 5'-(dihydrogen phosphate) monosodium (FMN-Na) as a hydrophilic PS into the lumen of halloysite nanotubes (HNTs), and attached the nanoassemblies (FMN-Na@HNTs), via Pickering effects, to the outer surfaces of giant unilamellar vesicles (GUVs) of phospholipids. We also prepared GUVs dopped with lumiflavin (LF) as a lipophilic PS having a 1O2 quantum yield comparable to FMN-Na. FMN-Na capsulated in HNT was characterized by a longer triplet excited state lifetime (12.1 μs) compared to FMN-Na free in solution (7.5 μs), and FMN-Na in both forms efficiently generated 1O2 upon illumination. The spatio-effects of PS on the photosensitized morphological changes of membranes were studied using conventional optical microscopy by monitoring GUV morphological changes. Upon light exposure (400-440 nm), the GUVs attached with FMN-Na@HNT merely experienced membrane deformation starting from the original spherical shape, ascribed to Type II photosensitization with 1O2 as oxidant. In contrast, photooxidation of LF dopped GUVs mainly led to membrane coarsening and budding assigned to Type I photosensitization. The spatial effects of PS on photosensitized morphological changes were related to the different lipid oxidation products generated through Type I and Type II photosensitized lipid oxidation.
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Liu XC, Skibsted LH. Strontium increasing calcium accessibility from calcium citrate. Food Chem 2021; 367:130674. [PMID: 34343801 DOI: 10.1016/j.foodchem.2021.130674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/04/2021] [Accepted: 07/20/2021] [Indexed: 11/30/2022]
Abstract
Strontium chloride added to aqueous suspensions of metastable calcium citrate tetrahydrate increased calcium ion activity measured electrochemically without transition of metastable tetrahydrate to stable calcium citrate hexahydrate as shown by DSC. Calcium activity increase was explained by lower solubility of strontium citrate pentahydrate formed (8.9 × 10-4 M at 25 °C) increasing with temperature compared to calcium citrate tetrahydrate (1.6 × 10-3 M) decreasing with temperature. Strontium binding to citrate was found endothermic, ΔH0 = 45 kJ∙mol-1 at 25 °C, while calcium binding shows variation from ΔH0 = 94 kJ∙mol-1 at 10 °C becoming exothermic above physiological temperature with ΔH0 = -9 kJ∙mol-1 at 45 °C as determined from temperature and concentration variation in electric conductivity. These differences in solution thermodynamics and pH effect on complex formation between calcium and strontium citrate are discussed in relation to biomineralization.
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Lu Y, Xu Y, Song MT, Qian LL, Liu XL, Gao RY, Han RM, Skibsted LH, Zhang JP. Promotion effects of flavonoids on browning induced by enzymatic oxidation of tyrosinase: structure-activity relationship. RSC Adv 2021; 11:13769-13779. [PMID: 35423946 PMCID: PMC8697750 DOI: 10.1039/d1ra01369f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/05/2021] [Indexed: 12/14/2022] Open
Abstract
Tyrosinase, widely distributed in nature, is a copper-containing polyphenol oxidase involved in the formation of melanin. Flavonoids are most often considered as tyrosinase inhibitors but have also been confirmed to be tyrosinase substrates. Four structure-related flavonoids including flavones (apigenin and luteolin) and flavonols (kaempferol and quercetin) are found to promote not inhibit browning induced by tyrosinase catalyzed oxidation both in model systems and in mushrooms under aerobic conditions. A comparison with enzymatic oxidation and autooxidation of flavonoids alone has helped to clarify why flavonoids function as a substrate rather than an inhibitor. Flavonoids almost do not affect the kinetics of melanin formation from enzymatic oxidation of l-dopa in excess. In addition, a new brown complex formed during the reaction of flavonoid quinone and dopaquinone is suggested to enhance the browning effects by competing with isomerization and autooxidation. Structure-activity relationships of the four flavonoids in melanin formation leading to browning induced by autooxidation and enzymatic oxidation confirm the enzymatic nature of the browning.
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Jiang Y, Liu XC, de Zawadzki A, Skibsted LH. Binding of calcium to l-serine and o-phospho-l-serine as affected by temperature, pH and ionic strength under milk processing conditions. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2020.104875] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Wang J, Aalaei K, Skibsted LH, Ahrné LM. Lime Juice Enhances Calcium Bioaccessibility from Yogurt Snacks Formulated with Whey Minerals and Proteins. Foods 2020; 9:foods9121873. [PMID: 33339103 PMCID: PMC7765558 DOI: 10.3390/foods9121873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022] Open
Abstract
Yogurt-based snacks originally with a calcium content between 0.10 and 0.17 mmol/g dry matter were enriched with a whey mineral concentrate and whey protein isolate or hydrolysate. Whey mineral concentrate was added to increase the total amount of calcium by 0.030 mmol/g dry matter. Calcium bioaccessibility was determined following an in vitro protocol including oral, gastric, and intestinal digestion, with special focus on the effect of lime juice quantifying calcium concentration and activity. Calcium bioaccessibility, defined as soluble calcium divided by total calcium after intestinal digestion amounted to between 17 and 25% for snacks without lime juice. For snacks with lime juice, the bioaccessibility increased to between 24 and 40%, an effect attributed to the presence of citric acid. Citric acid increased the calcium solubility both from whey mineral concentrate and yogurt, and the citrate anion kept supersaturated calcium soluble in the chyme. The binding of calcium in the chyme from snacks with or without lime juice was compared electrochemically, showing that citrate increased the amount of bound calcium but with lower affinity. The results indicated that whey minerals, a waste from cheese production, may be utilized in snacks enhancing calcium bioaccessibility when combined with lime juice.
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Garcia AC, Hansen JS, Bailey N, Skibsted LH. Slow lactate gluconate exchange in calcium complexes during precipitation from supersaturated aqueous solutions. Food Res Int 2020; 137:109539. [PMID: 33233167 DOI: 10.1016/j.foodres.2020.109539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/22/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
Saturated solutions of calcium l-lactate in water or in deuterium oxide continuously dissolve calcium l-lactate by addition of solid sodium d-gluconate and become strongly supersaturated in calcium d-gluconate due to no or slow precipitation. The quantification of total dissolved calcium allied with the calcium complexes equilibrium constants allowed an ion speciation, which shows an initial non-thermal and spontaneous supersaturation of more than a factor of 50 at 25 °C only slowly decreasing after initiation of precipitation of calcium d-gluconate after a lag phase of several hours. A mathematical model is proposed, based on numerical solution of coupled differential equations of dynamics of l-lactate and d-gluconate exchange during the lag phase for precipitation and during precipitation. A slow exchange of l-lactate coordinated to calcium with d-gluconate is indicated with a time constant of 0.20 h-1 in water and of 0.15 h-1 in deuterium oxide and a kinetic deuterium/hydrogen isotope effect of 1.25. Such spontaneous non-thermal supersaturation and slow ligand exchange with a pseudo first order equilibration process with a half-life of 3.5 h in water for calcium hydroxycarboxylates can help to understand the higher calcium bioavailability from calcium hydroxycarboxylates compared to simple salts.
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Thybo CD, Lillevang SK, Skibsted LH, Ahrné L. Calcium balance during direct acidification of milk for Mozzarella cheese production. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109677] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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de Zawadzki A, Paganelli MO, Garcia AC, Skibsted LH. Hydroxycarboxylate combinations for increasing solubility and robustness of supersaturated solutions of whey mineral residues. Food Res Int 2020; 136:109525. [PMID: 32846592 DOI: 10.1016/j.foodres.2020.109525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/24/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022]
Abstract
Calcium phosphates present in whey mineral residue is a potential source of calcium for dietary purposes. Combinations of aqueous isocitrate and citrate were found more efficient than each of the isomers in dissolving dried insoluble whey processing mineral residues spontaneously forming supersaturated solutions. Hydrogen isocitrate was found around 30% less efficient in these non thermal dissolution processes compared to hydrogen citrate based on amount of dissolved calcium. In contrast, the lag phase of up to 4 h for precipitation of calcium citrate from the supersaturated solutions was significantly longer when calcium isocitrate was present. Highest degree of supersaturation with longest lag phase for precipitation was found for citrate/isocitrate combinations in a 1:1 ratio. Addition of calcium saccharate during dissolution further prolonged the lag phase simultaneously preserving the higher supersaturation degrees. Combinations of the three hydroxycarboxylates seem accordingly to provide a basis for increasing calcium availability from dried whey mineral fractions consisting mainly of calcium hydrogen phosphate and hydroxyapatite of low solubility with the perspective of transforming a side stream from cheese production into valuable functional foods.
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Qian LL, Lu Y, Xu Y, Yang ZY, Yang J, Zhou YM, Han RM, Zhang JP, Skibsted LH. Alkaline earth metal ion coordination increases the radical scavenging efficiency of kaempferol. RSC Adv 2020; 10:30035-30047. [PMID: 35518270 PMCID: PMC9056298 DOI: 10.1039/d0ra03249b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 07/08/2020] [Indexed: 01/07/2023] Open
Abstract
Flavonoids are used as natural additives and antioxidants in foods, and after coordination to metal ions, as drug candidates, depending on the flavonoid structure. The rate of radical scavenging of the ubiquitous plant flavonoid kaempferol (3,5,7,4'-tetrahydroxyflavone, Kaem) was found to be significantly enhanced by coordination of Mg(ii), Ca(ii), Sr(ii), and Ba(ii) ions, whereas the radical scavenging rate of apigenin (5,7,4'-trihydroxyflavone, Api) was almost unaffected by alkaline earth metal (AEM) ions, as studied for short-lived β-carotene radical cations (β-Car˙+) formed by laser flash photolysis in chloroform/ethanol (7 : 3) and for the semi-stable 2,2-diphenyl-1-picrylhydrazyl radical, DPPH˙, in ethanol at 25 °C. A 1 : 1 Mg(ii)-Kaem complex was found to be in equilibrium with a 1 : 2 Mg(ii)-Kaem2 complex, while for Ca(ii), Sr(ii) and Ba(ii), only 1 : 2 AEM(ii)-Kaem complexes were detected, where all complexes showed 3-hydroxyl and 4-carbonyl coordination and stability constants of higher than 109 L2 mol-2. The 1 : 2 Ca(ii)-Kaem2 complex had the highest second order rate constant for both β-Car˙+ (5 × 108 L mol-1 s-1) and DPPH˙ radical (3 × 105 L mol-1 s-1) scavenging, which can be attributed to the optimal combination of the stronger electron withdrawing capability of the (n - 1)d orbital in the heavier AEM ions and their spatially asymmetrical structures in 1 : 2 AEM-Kaem complexes with metal ion coordination of the least steric hindrance of two perpendicular flavone backbones as ligands in the Ca(ii) complex, as shown by density functional theory calculations.
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Christiansen MV, Pedersen TB, Brønd JN, Skibsted LH, Ahrné L. Physical properties and storage stability of reverse osmosis skim milk concentrates: Effects of skim milk pasteurisation, solid content and thermal treatment. J FOOD ENG 2020. [DOI: 10.1016/j.jfoodeng.2020.109922] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wang J, Aalaei K, Skibsted LH, Ahrné LM. Bioaccessibility of calcium in freeze-dried yogurt based snacks. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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