Soluble Calcium Content Research Articles

Preparation and characterization of grouper bone peptides-calcium complex by lactic acid bacteria fermentation

In this study, grouper bone peptides-calcium complex (GPs-Ca) was prepared by lactic acid bacteria fermentation, and its structure and stability were analyzed. Response surface methodology (RSM) optimization was used to determine the optimal fermentation conditions as follows: 4% (v/v) inoculum size, 4.5 g/100 mL glucose addition and fermentation time 75 h,under which the soluble calcium content was 5953.61 mg/L and the peptide content was 21.75 mg/mL. The results of ultraviolet–visible absorption spectroscopy (UV) and fluorescence spectroscopy (Fs) showed a significant spectral shift for GPs-Ca relative to grouper bone peptides (GPs), indicating that peptide combined with calcium to produce a new substance after fermentation. Fourier transform infrared spectroscopy (FTIR) showed that carboxyl groups participated in the formation of GPs-Ca. Scanning electron microscopy (SEM) showed that calcium ions were embedded or adsorbed on the peptide surface. According to the stability analysis, GPs-Ca was stable during heating, alkaline environment and intestinal digestion, but easily dissociated in acidic environment. GPs-Ca prepared by lactic acid bacteria fermentation has the potential to be used as a new type of calcium supplement product, which provides a scientific basis for the high-value utilization of grouper bone.

Gelling properties of acid-induced tofu (soybean curd): Effects of acid type and nano-fish bone.

The effects of different types of acid coagulants and nano fish bone (NFB) additives on the characteristics of tofu were investigated using texture analyzers, SEM, FT-IR, and other techniques. The breaking force and penetration distance, in descending order, were found in the tofu induced by glucono-d-lactone (GDL) (180.27g and 0.75cm), citric acid (152.90g and 0.74cm), lactic acid (123.33g and 0.73cm), and acetic acid (69.84g and 0.58cm), respectively. The syneresis of these tofu samples was in the reverse order (35.00, 35.66, 39.66, and 44.50%). Lightness and whiteness were not significantly different among the different samples. Regardless of the acid type, the soluble calcium content in the soybean milk was significantly increased after adding NFB. As a result, the breaking force and penetration distance of all tofu samples increased significantly, but the syneresis decreased. Compared with tofu coagulated by other acids, GDL tofu formed a more uniform and dense gel network maintained by the highest intermolecular forces (especially hydrophobic interactions). Regarding the secondary structure, the lowest percentage of α-helix (22.72%) and, correspondingly, the highest β-sheet (48.32%) and random coil (18.81%) were noticed in the GDL tofu. The effects of NFB on the tofu characteristics can be explained by the changes in the gel network, intermolecular forces, and secondary structure, which were in line with the acid type. The characteristics of acid-induced tofu can be most synergistically improved by coagulation with GDL and NFB.

Sulfate resistance of carbonated basic oxygen furnace slag-metakaolin-Portland cement blends

Basic oxygen furnace slag (SS) is prone to carbonation due to its alkaline properties. The combined use of carbonated basic oxygen furnace slag (CSS) with metakaolin (MK) as a composite supplementary cementitious material (CSS-MK) can improve the reactivity of CSS and significantly lower the overall embodied CO2 emission. However, the impact of CSS-MK on the resistance of external sulfate attack (ESA) of cement remains unclear. This study aims to clarify the influence of CSS-MK on the resistance of cement to ESA. Compressive strength, water absorption, and electrical flux before ESA, and macro-scale expansion, microstructure, and evolution of phase assemblage during ESA were investigated. Results indicate that CSS-MK exhibits higher strength reactivity compared to SS-MK, enabling a 30% cement replacement level without compromising compressive strength after 7 days. CSS-MK reduces water absorption by 37.9% and electrical flux by 67.6%, enhancing transport property and reducing sulfate ion intrusion into the cement paste. The carbonation treatment transforms calcium silicate in SS into CaCO3, decreasing soluble calcium content, and creating a CaCO3-based passivation layer that inhibits sulfate ion corrosion. Meanwhile, the reaction in CSS-MK blends between the CaCO3 in CSS and MK consumes Ca(OH)2, forms ettringite and thermodynamically more stable carboaluminate, and results in the absence of monosulfate prior to ESA and the presence of carboaluminate during ESA, which consequently decreases ettringite content by 40% in paste after 240 days of ESA. Furthermore, at the macroscopic level, the expansion decreased by 85.2% after 360 days of ESA, effectively mitigating specimen cracking and damage.

Optimization of ultrasound-assisted enzymatic hydrolysis of channel catfish (Ictalurus punctatus) frames yield high-calcium and high-amino acid hydrolysates

ABSTRACT In this study, a high-calcium and high-amino acid fish frame hydrolyzate (FFH) was prepared from channel catfish (Ictalurus punetaus) through ultrasound-assisted enzymatic hydrolysis (UAEH). A 4-factor and 3-level Box-Behnken design of response surface methodology was employed to optimize the hydrolysis conditions, where the independent variables were sonication power (W), sonication time (min), enzyme activity (U) and water-substrate ratio (v/w). The degree of hydrolysis (DH) and soluble calcium content (SCC) were used as response factors. The optimal hydrolysis conditions were found to be sonication power (X1) = 492.91 W, sonication time (X2) = 15.01 min, enzyme activity (X3) = 6677.88 U, and water-to-substrate ratio (X4) = 3.56 v/w. Under these conditions, UAEH effectively disintegrated fish frame collagen and converted bound calcium to soluble calcium. Nevertheless, this study investigated the pattern of collagen transformation into short peptides and free amino acids throughout the degradation process. These findings highlight the potential of the FFH from channel catfish to serve as a foundation for creating highly nutritious food additive. The outcomes of this study further enhance the food industry’s ability to capitalize on the nutritional benefits offered by fish frame hydrolyzates. This expansion of health-focused product options and endorsement of the sustainable use of fish by-products harmonizes seamlessly with the industry’s evolving goals of waste reduction and value optimization.

Effect of Prechilling and Exogenous Gibberellin on Seed Germination of Primulina Eburnea: A Calcium-Rich Vegetable

Calcium-rich food and calcium supplements are expensive, especially for people in developing countries. Primulina eburnea is a calcium-rich vegetable with a high soluble calcium content in its leaves. In this study, we investigated the effects of prechilling and exogenous gibberellin on P. eburnea seed germination. Our results showed that both prechilling time and exogenous gibberellin affect P. eburnea seed germination. Three days prechilling increased germination percentage by 20.7-40.6%; mean germination time and time to first germination were reduced, indicating faster germination. A longer cold treatment enhanced the germination percentage but delayed the germination time. Prechilled P. eburnea seeds germinated 17.3-40.6% more when they were treated with GA3, but high GA3 did not shorten the germination time. Combination of three days prechilling and 50 ppm GA3 is the optimal treatment for P. eburnea seed germination. This research provides a powerful tool to accelerate breeding and cultivating this calcium-rich vegetable.

Developing an optical backscatter method for determining casein micelle particle size in heated milk

A plethora of different factors, such as heat treatment, pH, soluble calcium and phosphate concentrations, colloidal calcium phosphate, ionic strength, redox potential, etc., affect functionally of critical milk components such as casein micelles, fat globules and whey proteins. These physicochemical changes induce fat- or protein-protein interactions that would be associated to changes in particle size that might be revealed using light backscatter measurements. We hypothesized that inline, simple, low-cost light backscatter measurements might have the potential to provide functionally related information, representing an interesting opportunity for process control. Casein micelle particle size and near infrared light backscatter spectra were measured in milks heat treated at 80 and 90 °C and pH 6.3, 6.7 and 7.1 in order to obtain prediction models for estimating changes in casein micelle particle size during milk heat treatment. Light intensity was measured over a spectral range of 200–1100 nm using a simple optical backscatter sensor and was implemented into models for particle size predictions as a function of heat treatment temperature and pH. Models which included an exponential factor containing a ratio of two specific wavebands were found to improve R2 when compared to single wavelength models. The best model exhibited an R2 of 0.993 and SEP of 2.36 nm. The developed prediction models show promise for in-line monitoring of whey protein denaturation and casein micelle particle size.

Effect of Different Temperature-Controlled Ultrasound on the Physical and Functional Properties of Micellar Casein Concentrate.

Micellar casein concentrate (MCC) is a novel dairy ingredient with high protein content. However, its poor functional properties impair its potential for further application, highlighting the importance of using innovative processing methods to produce modified MCC, such as ultrasound (US). This work investigated the impact of US on the physical and functional properties of MCC under temperature-controlled and -uncontrolled conditions for different time intervals. Under temperature-controlled ultrasound (TC-US) treatment, a reduction was found in the supernatant particle size of casein micelles. Soluble calcium content and hydrophobicity increased following ultrasound treatment at 20 °C, resulting in a remarkable improvement in emulsification. However, long-time ultrasonication led to an unstable state, causing the MCC solutions to show shear thinning behavior (pseudoplastic fluid). Compared with 50 °C temperature-controlled ultrasonication, ultrasonication at 20 °C had a greater influence on particle size, viscosity and hydrophobicity. These findings indicate that 20 °C TC-US could be a promising technology for the modification of MCC.

Liming with CaCO3 or CaO affects aggregate stability and dissolved reactive phosphorus in a heavy clay subsoil

A 22-month incubation experiment was conducted to study the effect of lime on clay dispersion, wet aggregate stability (WAS) and dissolved reactive phosphorus (DRP), using a heavy clay subsoil with an initial pH of 7.0 and 7.3 g kg−1 of soil organic carbon. Lime was applied to achieve soil pH values of 7.5, 8 and 8.4. Clay dispersion decreased linearly with increased pH (corresponding to an increase in lime amount) for both lime types (R2 = 0.44 for CaO; R2 = 0.53 for CaCO3, P < 0.05), with a decrease of 2–16 % (CaO) and 3–17 % (CaCO3) compared with the control.Both WAS and DRP followed piece-wise linear functions, with an increase and peak around pH 7.5–7.8, and a decline at higher pH (WAS: R2 = 0.73 for CaO, R2 = 0.68 for CaCO3, P < 0.001; DRP: R2 = 0.84 for CaCO3, R2 = 0.33 for CaO, P < 0.001). Wet aggregate stability increased on average by 13 % and 11 % at the lowest and intermediate levels, respectively, compared with the control. At the highest lime application rate, WAS was 6 % (CaO) and 8 % (CaCO3) lower than in the control. These differences were probably caused by changes in electrical charge and in concentrations of soluble calcium and dissolved organic carbon (DOC) as the pH increased. More studies are needed to understand the processes in detail and to draw conclusions that are more robust.

تأثير خصائص السكان في استخدام المياه والمحافظة عليها من التلوث في مدينة عنيزة: دراسة جغرافية

استهدفت هذه الدراسة تحديد الخواص الطبيعية والكيميائية والبكتيرية لمياه الشرب في الشبكة العامة والخزانات الأرضية والشبكة المنزلية الداخلية ومقارنتها بخواص مياه الشرب الطبيعية والكيميائية الواردة في المواصفات القياسية السعودية. إضافة إلى دراسة تباين هذه الخصائص بين الشبكة العامة، والخزانات، الشبكة الداخلية لأحياء مدينة عنيزة التي شملتها الدراسة وهي القادسية، السليمانية، الملك خالد، وسط المدينة، المطار، المنتزه، مليحة، السلام وكذلك الكشف عن أهم المتغيرات التي تؤثر سلبيا وايجابيا عل خواص مياه الشرب. وأظهرت الدراسة مطابقة خواص مياه الشرب الطبيعية والكيميائية في الشبكة العامة لخواص مياه الشرب في المواصفات القياسية السعودية، في حين أظهرت الدراسة أن هناك تباينا بين خواص مياه الشرب في الشبكة العامة وخواص مياه الشرب في الخزانات الأرضية والشبكة المنزلية الداخلية، وتبين أيضا أن هناك تباينا مكانيا في خواص مياه الشرب بين الأحياء المدروسة التي شملتها الدراسة. وأثبتت الدراسة أن عمر الشبكة العامة الرئيسية قد تسبب في تباين قيم الأملاح الكلية الذائبة، الكلوريدات، العسر الكلي، الكالسيوم في مياه الشبكة. ولم تؤثر المسافة الفاصلة بين خزان الضخ الرئيس والمنزل على التباين في قيم معظم العناصر باستثناء الكبريتات وكذلك أظهرت النتائج ارتفاع قيم الأس الهيدروجيني لمياه الشرب في الأحياء التي توجد بها شبكة الصرف الصحي أكثر من الأحياء التي تفتقر إليها. وقد تبين ايضا أن تكرارية تنظيف الخزان والمسافة الفاصلة بين الخزان وخزان الصرف الصحي تعد من أهم المتغيرات التي تؤثر على خواص مياه الشرب في الخزانات المنزلية حيث أثرت على التباين في قيم الأملاح الكلية الذائبة، الكلوريدات، الكبريتات، العسر الكلي، الكالسيوم، التوصيل الكهربائي، في حين أثر نوع شبكة المياه المنزلية الداخلية على التباين في قيم الأملاح الكلية الذائبة، الكلوريدات، الكبريتات، التوصيل الكهربائي في مياه تلك الشبكة. كما أشارت الدراسة إلى التأثير الايجابي لارتفاع الدخل الشهري لصاحب المنزل وملكية المسكن فقد أدى ذلك إلى الاهتمام بنظافة الخزانات الارضية وبالتالي جودة مياه الشرب فيها.

Effects of nano fish bone on gelling properties of tofu gel coagulated by citric acid.

Tofu gel was made by using citric acid (0.14%) in combination with varied volumetric ratios (e.g., 0-4%) of nano fish bone (NFB). The gel properties were investigated by colorimetry, penetration tests, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. As the volumetric ratio increased from 0 to 3%, the soluble calcium concentrations of soymilk linearly increased from 1.78 to 6.42mg/mL. Correspondently, yield, moisture and texture values of the tofu gel increased continuously (p<0.05) while syneresis and whiteness decreased (p<0.05). Furthermore, ionic bonds, hydrophobic interactions and hydrogen bonds increased by 140%, 40% and 10%, respectively. With the addition of NFB, the α-helices of the soybean proteins changed to β-sheets and random coil structures. Additionally, the tofu gel network became more orderly and denser. The results confirmed that NFB can be utilized as a functional coagulant ingredient to improve the properties of acid-induced tofu gels.

Incorporating whey protein aggregates produced with heat and ultrasound treatment into rennet gels and model non-fat cheese systems

Native whey proteins (WP) are expulsed from cheese coagulation during syneresis. Although incorporating denatured WP aggregates into cheese gels has been previously proposed to improve the overall cheese yield, the effects of WP aggregate properties on gelation kinetics and protein retention are not yet fully understood. In this study, heat and power ultrasound were used to produce denatured whey protein aggregates with a wide range of sizes. The effects of size and hydrophobicity differences in WP aggregates produced by heat and heat coupled with ultrasound were investigated in relation to the kinetics of rennet gelation and protein retention in model non-fat cheddar cheeses. Rheological measurements showed that sufficiently large, denatured WP aggregates could avoid impairment of rennet gelation caused by native WP, irrespective of changes in the soluble calcium concentration or the surface hydrophobicity of the aggregates. WP aggregates formed by the combined heat and ultrasound treatment were more hydrophobic than the larger heat-treated aggregates and were better retained in the cheese. However, inclusion of sufficiently large aggregates in cheese milk conferred an openness to the cheese microstructure and showed promise in improving the otherwise rigid non-fat cheese.

Synthesis of Inorganic Pyrophosphatase-Nanodiamond Conjugates Resistant to Calcium and Fluoride.

Pyrophosphate arthropathy is the mineralization defect in humans caused by the deposition of microcrystals of calcium pyrophosphate dihydrate in joint tissues. As a potential therapeutic strategy for the treatment of pyrophosphate arthropathy, delivery of exogenous pyrophosphate-hydrolyzing enzymes, inorganic pyrophosphatases (PPases), to the synovial fluid has been suggested. Previously, we synthesized the conjugates of Escherichia coli PPase (Ec-PPase) with detonation synthesis nanodiamonds (NDs) as a delivery platform, obtaining the hybrid biomaterial retaining high pyrophosphate-hydrolyzing activity in vitro. However, most known PPases including Ec-PPase in the soluble form are strongly inhibited by Ca2+ ions. Because synovial fluid contains up to millimolar concentrations of soluble calcium, this inhibition might limit the in vivo application of Ec-PPase-based material in joint tissues. In this work, we proposed other bacterial PPases from Mycobacterium tuberculosis (Mt-PPase), which are resistant to the inhibition by Ca2+ ions, as an active PPi-hydrolyzing agent. We synthesized conjugates of Mt-PPase with NDs and tested their activity under various conditions. Unexpectedly, conjugates of both Ec-PPase and Mt-PPase with aminated NDs retained significant hydrolytic activity in the presence of well-known mechanism-based PPase inhibitors, fluoride or calcium. The incomplete inhibition of PPases by fluoride or calcium was found for the first time.

Mechanism on releasing and solubilizing of fish bone calcium during nano‐milling

AbstractFish bone, predominately composited by collagen and hydroxyapatite (HAP), is a natural calcium resource that possesses the potential to be used as functional ingredient in food application. In this study, five HAP suspensions with either collagen or amino acids were applied to simulate the releasing and solubilizing of fish bone calcium during nano‐milling. As milling time was increased, particle sizes from five suspensions gradually decreased and pH increased. The sizes and pH kept constant as the time was extended beyond 60 min (p &lt; .05). Initial soluble calcium content of HAP suspension fluctuated with milling time and was not increased after milling for 240 min. However, soluble calcium contents of HAP suspensions with collagen and amino acids continuously increased and reached the highest values of 106.70 and 147.34–645.68 μg/g, respectively. After nano‐milling, crystallinity of HAP particles declined and calcium element on the surface decreased and contents of free amino acid and peptides from fish bone suspension significantly increased (p &lt; .05). Our results suggested that the releasing and solubilizing of fish bone calcium during nano‐milling was mainly attributed to alterations on size and crystalline structure of HAP, and the chelating effects by amino acids and peptides.Practical ApplicationsFish bone is the main solid waste from fish processing industry. When properly processed, it possesses the potential to be used as food grade calcium additive. It has been reported that grittiness of fish bone could be neglected after reducing its particle to nanoscale. Furthermore, soluble calcium content was significantly increased, which might be benefit for improving calcium bioavailability of fish bone. However, there is no report regarding the release of calcium from fish bone during nano‐milling process so far. This research will provide scientific foundation for improving solubility of calcium from various natural resources in a physical method.

Impact of anaerobically digested biosolids characteristics and handling conditions on dewatering performance at multiple facilities.

Anaerobically digested biosolids (ABD) characteristics that affect dewatering were assessed at three water resource recovery facilities (WRRF) with different handling practices. Dewatering performance at the three sites corresponded to different levels ofsoluble chemical oxygen demand (COD), ammonia (NH4 -N), and mono- and divalent cation concentrationsin ADB. Capillary suction time (CST) and a modified centrifugal technique were used to determine optimum polymer doses and to assess the impact of handling conditions on dewatering performance. Both techniques indicated that polymer dosing between 15 and 20kg/dry tonne was optimal for all facilities and that biosolids mixing and pumping did not significantly impact dewaterability. The CST values of anaerobically digested biosolids decreased as temperature increased, but no significant difference was found for either temperature or location of dewatering facilities. Sludge viscosity and rheological properties that vary with temperature appeared to have influenced CST values. Modified centrifugal technique results indicated cake solids were not affected by polymer make-up water or ADB temperature when emulsion polymer was used. This study shows the value of laboratory testing of biosolids under controlled conditions to identify and correct potential problems in full-scale operations. PRACTITIONER POINTS: Capillary suction time and a modified centrifugal technique were used to assess the impact of different process-related and environmental factors on dewatering. Higher concentrations of soluble COD (potentiallyextracellular polymeric substances - EPS) and low calcium (Ca) in anaerobically digested biosolids align with reduced dewaterability. Cell disruption and break down of floc structures due to storage/mixing and pumping of biosolids did not appear to negatively impact dewatering. Modified centrifugal test results did not provide conclusive evidence of whether dewatering of anaerobically digested biosolids could be significantly impacted by temperature over the range 15-30°C, especially when emulsion polymer is used. This study shows the value of laboratory testing of biosolids under controlled conditions to identify potential problems in the full-scale operations.

Urban structure degradation caused by growth of plants and microbial activity

The purpose of this study was to isolate microorganisms associated to surface-affected concrete structures and to measure the in vitro dissolution of concrete based on the release of elements such as calcium and silicon. Although many microorganisms were detected only a fungus was capable of significantly decreasing the culture medium pH and releasing both elements. The molecular characterization allowed to identify the microorganism as Aspergillus carbonaurius, a citric-acid producing fungus that dissolved concrete in the in vitro test. After seven days of incubation, the soluble calcium concentration in the uninoculated culture medium containing concrete was 172.3 mg/L, while in the inoculated medium it was 525.0 mg/L. The soluble silicon concentration in the uninoculated medium was 10.3 mg/L, while in the inoculated medium it was 50.1 mg/L. These findings showed that plants and microorganisms rendered a synergistic effect accelerating the biodeterioration of concrete.

Impact of Flood 2010 on the Fertility Status of Soil of Tehsil Garhi Khairo, District Jacobabad, Pakistan

A field study was carried out to assess some measurable changes in chemical properties of the soil of taluka Garhi Khero, district Jacobabad that was affected by ‘Supra flood 2011’. Forty-five composite soil samples were collected from three sampling depths, 0-15 cm, 15-30 cm, and 30-45 cm for the determination of various chemical parameters such as pH, electrical conductivity, soluble sodium (Na+), potassium (K+), calcium (Ca+2), and magnesium (Mg+2). Results of the analysis were compared with the reference data that were studied before the flood. Results of the analysis revealed that due to flood, chemical nature of soil was changed from slightly alkaline to strongly alkaline. Before and after flood soil remains non-saline. There has been a significant increase in the optimum concentration of soluble sodium (Na+), calcium (Ca+2) and magnesium (Mg+2). However; potassium (K+) content of the soil was uniformly decreased. Keywords: Flood, soil, agriculture, crops, Jacobabad.

Technological attempts at producing cheese from donkey milk.

The work described in this Research Communication addressed the hypothesis that it is possible to produce cheese from donkey milk by appropriate adjusting of the cheesemaking parameters. A series of coagulation trials were performed on donkey milk, alone or fortified with goat milk (85/15 and 70/30, v/v), using calf rennet under different technological conditions. The parameters that changed were pH and concentration of soluble calcium, amount of rennet added and temperature of coagulation. Donkey milk gave rise to sufficiently firm curd only at 'extreme' technological conditions and, as expected, addition of goat milk improved coagulation. A cheesemaking protocol was developed for producing fresh cheese prototypes, which were checked for microbiological safety, chemical composition and sensory characteristics. Pure donkey milk gave 5·9% yield, cheese having 6·12 pH, 32·4% dry matter, 2·1% fat and 18·5% protein. The electrophoretic analysis ascertained that β-casein was the most abundant compound in donkey cheese, but whey proteins were also present in non-negligible amounts. Finally, the sensory evaluation demonstrated that all cheeses were acceptable and provided detailed description of their flavour characteristics.

Drought Effects on Growth, Water Content and Osmoprotectants in Four Olive Cultivars with Different Drought Tolerance

ABSTRACTThis study investigates the growth and leaf composition of 2-year-old olive trees (Persian cultivars: Fishomi and Dezful and Greek cultivars: Amigdalolia and Conservolia) in response to withholding irrigation for 30 days under a hot and dry environment. Drought stress limited stem elongation, stem diameter expansion, formation of new leaves, leaf area, and specific leaf weight of the plants. However, the effect of drought on inhibition of growth of ‘Fishomi’ plants was higher than the other cultivars. ‘Dezful’, ‘Amigdalolia’ and ‘Conservolia’ were able to preserve higher levels of leaf relative water content and membrane stability index under drought stress. Higher drought tolerance of these plants was related to higher concentration of soluble carbohydrates, proline, potassium, and calcium in their leaves.

The distribution and species of Ca2 + and subcellular localization of Ca2 + and Ca2 +-ATPase in grape leaves of plants treated with fluoroglycofen

Fluoroglycofen, a post-emergence herbicide used in vineyards to eradicate weeds, has previously been shown to turn grape leaves dark green following its use. Therefore, this study evaluates the relationship of dark green leaves with calcium form and subcellular distribution. To do this, we focused on the Ca2+ distribution and Ca2+-ATPase activity in leaf cells of one-year-old self-rooted Chardonnay grapevines treated with fluoroglycofen. Plants were separated into different treatments when they had seven or eight leaves, and different concentrations of fluoroglycofen were sprayed on the sand. The results showed that all of the soluble calcium content in the grape leaves that were treated with the highest concentration of fluoroglycofen (187.5gaiha−1) increased significantly. Specifically, the water-soluble organic acid calcium, pectate calcium, and calcium oxalate increased by 18.43%, 17.14%, and 31.05%, respectively, in the upper leaves than in the control. The subcellular distribution of Ca2+ in the dark green leaves increased significantly, especially in the cell wall and chloroplast, which increased by 25.54% and 24.10%, respectively. Through the ultrastructure localization of Ca2+ and Ca2+-ATPase contrasted with the control, the extracellular space and chloroplasts in the mesophyll cells of dark green leaves had large calcium pyroantimonate (Ca-PA) deposits. The extracellular space had fewer Ca2+-ATPase precipitation particles, whereas the chloroplasts had more. At the same time, a high concentration of fluoroglycofen decreased Ca2+-ATPase activity in grape leaves, which potentially might be due to disrupted regulation of calcium homeostatic mechanisms inside and outside of cells, resulting in a large number of Ca2+ accumulation in cells. The Ca2+ accumulation not only hindered the various cellular physiological reactions, but also caused leaves to become dark green in color.

Characteristics of Biocalcium Powders from Pre-Cooked Tongol (Thunnus tonggol) and Yellowfin (Thunnus albacores) Tuna Bones

Characteristics of biocalcium powder from pre-cooked tongol tuna bone (BTG) and yellowfin tuna bone (BYF) were investigated, in comparison with their calcined bone powder named CTG and CYF, respectively. Average calcium (40.3%) and phosphorus (19.19%) contents of CTG and CYF were higher than those of BTG and BYF (Ca: 26.74%, P: 12.72%). Nevertheless, similar mole Ca/P ratio (1.62–1.63) was observed among all samples. Mean particle size of all samples was approximately 14 μm. Both CTG and CYF powders exhibited the interconnected granular structure. BTG had higher b*- value than BYF (p < 0.05). Generally, CTG and CYF had lower b*-values with slightly higher L*-values than both BTG and BYF (p < 0.05). X-ray diffraction results indicated the presence of hydroxyapatite in all samples, in which their crystallinities were increased from 54% to 90% after calcination. Hydroxyproline and protein were detected in both biocalcium powders, but were not detectable in calcined bone powders. The abundance of volatile compounds was noticeably lower in BYF, compared to BTG. Negligible volatiles were detected in both calcined bone powders. Based on a simulated gastrointestinal tract study, both BTG and BYF had higher soluble calcium content than calcium carbonate and their corresponding calcined bone powders, indicating the higher availability for absorption.