Preparation and Partial Characterization of Eggshell Calcium Chloride

To minimize eggshell waste, calcium in eggshells was extracted as calcium chloride using 4% (w/v) HCl solution for an extraction period of 3 hs with the ratio of eggshell to HCl being 1:15 (w/v). After hydrolysis, the residues were removed by centrifugation at 1774 × g for 10 min, and the solution was heated to 110–115°C until dried, this gave an eggshell calcium chloride at a yield of 87.38% (w/w). The calcium chloride powder in this study was composed of 0.3% protein and 94.37% ash, with pH 5.27 and showed high solubility. It contained minute amount of heavy metal constituents within the specification of the Thai Food Act. X-ray diffraction analysis indicated that eggshell calcium chloride powder thus prepared was composed mainly of CaCl₂.2H₂O. The eggshell CaCl₂ was also tested for its functional property as a firming agent in canned rambutan. The results showed that both eggshell and commercial calcium chloride gave a firm texture to canned rambutan, therefore eggshell CaCl₂ can be prepared and used as food processing aids.     

Effectiveness of Hydrothermal‐Calcium Chloride Treatment and Chitosan on Quality Retention and Microbial Growth during Storage of Fresh‐Cut Papaya

Rapid degradation of fresh‐cut papaya limits its marketability. Hydrothermal treatments in combination with a calcium dip, applied to whole fruit before slicing, and also the application of chitosan as a coating film, have been found to have very good results in maintaining the quality of fresh‐cut fruits. Based on these considerations, the aim of this study was to evaluate the effect of hydrothermal treatment (HT; 49 °C, 25 min) containing calcium chloride (Ca; 1%, w/v) followed by dipping in chitosan (Chit; 1%, w/v, 3 min) on the physical, chemical, and microbial qualities of papaya slices stored at 5 °C for 10 d. Pulp color, firmness, ascorbic acid, total phenolics, β‐carotene, and lycopene were evaluated every 2 d while the microbial quality (mesophilics, psychrophilics, molds, and yeasts) was evaluated every 5 d. Fruit treated with HT‐Ca and HT‐Ca + Chit showed better color and firmness retention than Control and Chit. Papaya slices treated with HT‐Ca + Chit had higher nutritional content and lower microbial growth at the end of storage. The application of the HT‐Ca + Chit could be used to reduce deterioration processes, maintaining physical, chemical, and microbial qualities and increasing the shelf life of fresh‐cut papaya stored at 5 °C.     

Effect of calcium salts on the texture,structure and sensory acceptance of osmotically dehydrated guavas

The effect of additives, calcium chloride and calcium lactate (5–25 g kg^?1), on the osmotic dehydration of guavas with sucrose solutions was studied, aiming at the structural preservation of processed fruits. The osmotic process was evaluated from the reduction in weight of the guavas, water loss and solids gain, and the samples were analyzed with respect to calcium content, texture (stress and strain at failure, relaxation time and residual stress), structure by light microscopy and sensory acceptance. Calcium salts had a strong influence on the texture and structure of the processed guavas, resulting in the maintenance of tissue structure when calcium lactate was used at concentrations up to 15 g kg^?1, and calcium chloride was used at 5 g kg^?1. The sensory acceptability of guava was related to the structural and texture results. Calcium treatments did not improve guava's sensory acceptance. Guavas treated with calcium lactate showed good sensory acceptance, presenting slight inferior scores only at concentrations above 20g kg^?1, while CaCl₂ treated guavas showed average scores statistically equal to the sucrose and calcium lactate treated fruits only at 5 g kg^?1. Copyright © 2007 Society of Chemical Industry     

Effect of pretreatments and drying temperatures on sweet potato flour

Effect of pretreatments with 1 w/v% sodium hydrogen sulphite (NaHSO₃) and 1 w/v% calcium chloride (CaCl₂) and drying temperatures (55, 60 and 65 °C) on sweet potato flour were investigated. Flour treated with CaCl₂ had higher amounts of ascorbic acid and β‐carotene (10.61–12.54 and 3.26–3.46 mg 100 g^?1 wet basis, respectively) than that treated with NaHSO₃ (9.47–11.47 and 3.05–3.43 mg 100 g^?1 wet basis, respectively). Total phenolic content and water absorption index (wet basis) were highest at 65 °C when treated with NaHSO₃ (10.44 mg 100 g^?1 and 2.49 g g^?1 respectively) and CaCl₂ (9.52 mg 100 g^?1 and 2.85 g g^?1 respectively). Swelling capacity (wet basis) was highest at 60 °C when treated with CaCl₂ (2.96 g g^?1) whereas when treated with NaHSO₃ (2.85 g g^?1) it was highest at 55 °C. Freeze‐dried samples treated with NaHSO₃ had higher lightness and total phenolic content while CaCl₂‐treated samples had higher β‐carotene and ascorbic acid. The results showed that good quality flour could be produced after soaking in CaCl₂ and dried at 65 °C.     

Tenderness and flavor of leg cuts from meat goats influenced by calcium chloride injection

This study was conducted to assess the potential of improving tenderness of chevon using calcium chloride (CaCl₂) injection and its effect on the palatability characteristics of chevon. Primal leg cuts from meat goats were allotted to one of four treatments: either no injection (control) or injection with water, CaCl₂ (food grade, 2.2% w/v), or CaCl₂ plus a spice mix. The CaCl₂ injection improved tenderness of goat leg cuts, proven by Warner–Bratzler shear force values and sensory panels. Furthermore, panelists were not able to detect off-flavor problems associated with CaCl₂ injection. When CaCl₂ was injected into goat leg cuts with the beef spice mixture, it resulted in a more desirable flavor. Calcium injection did not influence flavor volatile compounds in cooked chevon leg cuts. The results indicate that CaCl₂ plus spice mix injection can be applied to improve tenderness of goat meat without detrimental effects on other sensory characteristics.     

Effect of calcium and calmodulin antagonists on ethylene biosynthesis in tomato fruits

The aim of this work was to elucidate the mode of action of calcium in calcium-inhibited ethylene biosynthesis. In one experiment, mature green tomatoes were treated with 1·5% (w/v) CaCl₂+60 μM N-6(aminohexyl)-1-naphthalenesulphonamide (W5). 1·5% (w/v) CaCl₂+60 μM N-6(aminohexyl)-5-chloro-1-naphthalenesulphonamide (W7), 1·5% (w/v) CaCl₂ alone or distilled water (control). The control and the W7 treatment had much higher ethylene production than either the CaCl₂ treatment alone or the CaCl₂+W5 treatment. In another experiment, similar tomatoes were treated with 1·5% (w/v) CaCl₂+15 μM trifluoperazine (TFP). 1·5% (w/v) CaCl₂ only, or distilled water (control). The treatment with 1·5% CaCl₂+15 μM TFP gave higher ethylene production than 1·5% (w/v) CaCl₂ without TFP, and nearly the same level as the control towards the end of the experimental period. For enzyme and intermediate metabolite assays, mature green tomatoes were treated with 1·5% (w/v) CaCl₂ plus either W5 or W7. W5 treatment had a lower ethylene forming enzyme (EFE) activity, higher 1-aminocyclopropane-1-carboxylic acid (ACC) concentration, similar levels of ACC synthase activity and 1-(malonylamino)-cyclopropane-1-carboxylic acid concentration, compared to the control and W7 treatment. As W7 is a more potent calmodulin antagonist than W5, these results suggest a calcium-calmodulin inactivation of EFE activity. © 1998 SCI.     

Application of different forms of calcium to tea soil to prevent aluminium and fluorine accumulation

Tea Camellia sinensis (L), is a well‐known accumulator of aluminium and fluorine from acidic soil. A reduction is desirable as aluminium and fluorine absorbed will leach into the tea liquor through infusion, thus posing a serious threat to the health of consumers. The present study aims to investigate the effects of adding different forms of calcium on Al and F uptake by tea plants, in order to reduce the concentrations of these elements contained in the plants. All true lime materials increased the soil pH and decreased soil extractable Al and F concentrations. There were no (p < 0.05) changes in pH values when CaCl₂ was added, and a slight decrease in Al and F concentrations was observed in the treatments with CaSO₄. Tea seedlings under the addition of CaSO₄ were the tallest and healthiest, followed by CaCl₂, CaCO₃, Ca(OH)₂ and CaO. Seedlings under large doses of Ca(OH)₂ and CaO were dead. Relative growth rates decreased significantly with the increase of calcium compounds except in CaSO₄ treatment. The highest Al concentration was also found in the treatment of 4000 mg CaSO₄ kg^?1; it then decreased gradually from 3364 to 933 mg Al kg^?1 in leaves. For all treatments in both varieties, F concentrations in leaves were lower than the control (374 mg kg^?1). Calcium chloride was a suitable agent for reduction of Al and F uptake by tea plants while maintaining a high growth rate of the seedlings. Copyright © 2004 Society of Chemical Industry     

The effect of calcium chloride and calcium lactate pretreatment concentration on peach cell integrity after high‐pressure processing

The objective of this study was to determine the effect of calcium chloride and calcium lactate pretreatments at different concentrations (1, 1.5 and 2% w/v) on enzymatic browning of clingstone and freestone peaches following high‐pressure processing (HPP) at 200 MPa for 10 min. Proton nuclear magnetic resonance (¹H‐NMR) relaxometry indicated that following calcium pretreatment and HPP, both peach types had lower percentages of water in the vacuole compartment and a simultaneous increase in the percentage of water in the cytoplasm compartment. Calcium pretreatment of freestone peaches did not affect the development of browning, regardless of the form of calcium or the concentration, whereas calcium lactate pretreatment undesirably enhanced clingstone peach discoloration. Calcium pretreatments have the potential to reduce the loss of cell integrity that results from HPP; however, in this study, the effect was not sufficient to inhibit the interaction between the polyphenol oxidase enzyme that catalyses browning and its substrates.     

Fortification of reconstituted skim milk powder with different calcium salts: Impact of physicochemical changes on stability to processing

Reconstituted skim milk powder (RSMP) was fortified with 12.5 mM/L calcium (Ca) using soluble [Ca chloride (CChlor), Ca gluconate (CGluc) or Ca hydroxide (CHyd)] or insoluble [Ca carbonate (CCarb), Ca phosphate (CPhos) or Ca citrate (CCit)] salts. CPhos and CCit decreased heat stability moderately at 140 °C, while CCarb had no effect. Soluble salts had a pronounced destabilising effect at 140 °C due to increased ionic Ca levels. After a laboratory‐scale high‐temperature short‐time heating process, CHyd‐fortified RSMP had a lower viscosity than all other samples. CChlor and CGluc increased sedimentation during accelerated physical stability testing, with CHyd causing greater sedimentation than CChlor or CGluc.     

The addition of calcium chloride in combination with a lower draining pH to change the microstructure and improve fat retention in Cheddar cheese

Calcium chloride addition and the whey draining pH are known to impact on cheese making. The effect of 100 or 300 mg kg⁻¹ calcium chloride (CaCl₂) and the whey draining pH (6.2 or 6.0) on the microstructure of Cheddar cheese was assessed using confocal and cryo scanning electron microscopy. The gel made with 300 mg kg⁻¹ CaCl₂ was found to have a denser protein network and smaller pores than the gel with lower or no CaCl₂ addition. CaCl₂ addition reduced fat lost to the sweet whey. The texture of the cheeses with a lower draining pH was harder and moisture content lower. Our results show that the combination of calcium addition and lower draining pH could be used to increase network formation at the early stages of cheese making to improve fat retention while maintaining a similar level of total calcium in the final cheese.     

Thermal stability of soy protein isolate and hydrolysate ingredients

The objective of this study was to characterize the effects of pH, protein concentration and calcium supplementation on thermal stability, at 140 °C, of soy protein isolate (SPI) and soy protein hydrolysate (SPH) ingredients. Increasing pH between 6.4 and 7.5 led to significantly (p < 0.05) higher mean heat coagulation times (HCTs) at 140 °C, for all soy protein ingredients at 1.8, and 3.6% (w/v) protein. Increasing protein concentration from 1.8 to 7.2% (w/v) led to shorter HCTs for protein dispersions. Calcium supplementation up to 850 mg/L, except in the case of supplementation of SPI 1 with calcium citrate (CaCit), decreased HCT for soy protein ingredient dispersions, at pH 6.4 – 7.5. No significant differences (p < 0.05) were found in mean HCT for dispersions supplemented with calcium chloride (CaCl₂) and those supplemented with CaCit at 450, 650 and 850 mg/L Ca²⁺, in the pH range 6.4–7.5.     

Optimising chitosan–pectin hydrogel beads containing combined garlic and holy basil essential oils and their application as antimicrobial inhibitor

Chitosan–pectin hydrogel beads that trap and release the maximal amount of combined garlic and holy basil essential oils to inhibit food microorganisms were developed based on the central composite design, with chitosan (0.2–0.7% w/v), pectin (3.5–5.5% w/v) and calcium chloride (CaCl₂) (5.0–20.0% w/v) contents. The optimal bead consisted of 0.3–0.6% w/v chitosan, 3.9–5.1% w/v pectin and 8.0–17.0% w/v CaCl₂, which had a high encapsulation efficiency (62.16–79.06%) and high cumulative release efficiency (31.55–37.81%) after storage at 5 °C for 15 days. Optimal hydrogel beads were packed into a cellulose bag to evaluate antimicrobial activity by the disc volatilisation method. The beads inhibited Bacillus cereus, Clostridium perfringens, Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes and Staphylococcus aureus but did not affect Lactobacillus plantarum and Salmonella Typhimurium. The oil-containing beads could potentially be applied in food packaging to inhibit the mentioned microorganisms.     

Effect of calcium on the physical properties of stirred probiotic yogurt

The effect of calcium on the viscosity, firmness, and smoothness, as determined by extent of nodulation, of stirred probiotic yogurt produced by bacterial fermentation was investigated. Standardized milk for yogurt manufacture was prepared, and calcium was added or removed from the system. Calcium was added as Ca²⁺ in the form of CaCl₂ (up to 13.6 mM) or nonionic calcium as Gadocal-K (calcium potassium citrate; up to 49.8 mM). Calcium was removed by chelating with sodium citrate (up to 16 mM) or by cation exchange with Amberlite IR-120 plus (sodium form) resin (up to 10 g/L). Calcium chloride and sodium citrate were added either before or after heat treatment of milk, and nonionic calcium was added before heat treatment. Calcium removal by ion exchange was performed before heat treatment. Neither Ca²⁺ addition nor removal by chelation with citrate resulted in stirred yogurt with viscosity, firmness, and smoothness superior to those of the control yogurt, whereas addition of 49.8 mM nonionic calcium and removal of calcium (5.6 mM or ∼10% of total calcium) by cation exchange improved the firmness and viscosity without affecting yogurt smoothness. The study identified Gadocal-K as a possible source of calcium fortification of stirred yogurt without loss of texture.     

The effect of calcium dips combined with mild heating of whole kiwifruit for fruit slices quality maintenance

The effect of moderate heat treatment combined with calcium dips on the quality of minimally processed kiwifruit was studied. Whole fruits were treated for 25 min at 45 °C by dipping in deionised water or CaCl₂ solutions (1%, 2% and 3% (w/v)) and cooled to 4 °C. Twenty-four hours later fruits were peeled, sanitized, cut into slices and packed. The firmness of kiwifruit slices’ was subsequently evaluated during 8 days of storage. Calcium content, pectinmethylesterase activity and heat shock proteins accumulation were also investigated. Heat treatment conducted in water induced a firming effect and avoid softening of fruit slices while calcium dips had a marginal effect on this parameter. A calcium loss was observed due to dip treatment, but this effect was minimized when treatment was conducted in 3% CaCl₂ solution. The firming effect provided is due to the activation of pectinmethylesterase and the presence of calcium in treatment solution reduces or inhibits enzyme activation. Under the tested conditions, no heat shock proteins de novo synthesis was detected.     

Improving textural quality in frozen jalapeño pepper by low temperature blanching in calcium chloride solution

The effects of low temperature blanching in calcium chloride solution of jalapeño peppers prior to freezing, on firmness retention, pH, methanol, colour and calcium ions of the product, were evaluated by response surface methodology. Texture, methanol content and pH were affected by all of the variables studied (P = 0.05). The optimum response was obtained at temperatures of 63.3–66 °C, calcium chloride concentrations of 0.17–0.21 m , immersion time of 11.6–14.4 min, with a holding time after blanching of 56.6–66.1 min. Microscopic evaluation of the thawed pepper showed that blanching in CaCl₂ solution provided a protective effect in maintaining cell wall integrity.     

Pre‐harvest application of calcium to control black heart disorder in Mauritius pineapples during low‐temperature storage

The chill‐sensitive pineapple cv. Mauritius grown in Sri Lanka was subjected to different pre‐harvest calcium treatments in order to determine an effective means of increasing calcium levels in the fruit, thereby reducing the incidence and severity of black heart disorder. Treatments of CaO and CaSO₄ (10 g and 15 g per plant) were applied to soil as side dressing 6 weeks after planting, while CaCl₂ (1.3 g and 2 g per fruit) were applied as a spray treatment to 1‐month‐old fruit (red bud stage). Fruit were harvested at the 10–20% yellow stage of maturity. Incidence of black heart disorder and observations on total acids, °Brix, ascorbic acid content and total calcium levels were recorded on waxed and unwaxed fruit before and after 17 days storage at 10 °C and 85–90% relative humidity, followed by 2 days at ambient temperature 28 ± 2 °C. Combined treatment of pre‐harvest CaCl₂ fruit spray (1.3 g per fruit) followed by post‐harvest wax treatment showed 80% good fruit with no black heart symptoms after low‐temperature storage at 10 °C for 17 days followed by 2 days at ambient temperature of 28 ± 2 °C. However, side dressings of CaO and CaSO₄ were found to be less effective in reducing the symptoms, showing less than 30% of good fruit without black heart symptoms. Both core and flesh regions of pineapples subjected to pre‐harvest fruit spray treatment showed higher total calcium levels compared to controls as well as other calcium treatments. Results obtained from the field experiment confirmed that the calcium chloride fruit spray treatment of 1.3 g per fruit in three split doses at 2‐week intervals could be used to reduce the incidence of black heart disorder in Mauritius pineapples. Copyright © 2005 Society of Chemical Industry     

Calcium chloride irrigation influence on yield,calcium content,quality and shelf‐life of the white mushroom Agaricus bisporus

Seven CaCl₂ irrigation treatments (0.15, 0.25, 0.35, 0.45, 0.55, 0.75 and 1.00%) were applied to the Agaricus bisporus white strain A15 (Sylvan) in order to evaluate, in comparison with the water‐irrigated crop, their effect on production characteristics, ie yield, sporophore number and size mix, average mushroom weight as well as pileus and stipe Ca content. In addition, initial mushroom colour and texture in three successive flushes and their variations during post‐harvest storage for 8 days at 4 °C and for 2 days at 18 °C were determined. Statistical analysis of data revealed that crop yields were not affected by the individual treatments, whereas the mushroom number was reduced and the average sporophore weight was enhanced. A strong positive correlation was established between CaCl₂ dosage and Ca content of fresh mushrooms, which increased considerably in the third flush by accumulating in both pileus and stipe parts (the former containing less Ca than the latter) and presented a maximum for the 0.75 and 1.00% CaCl₂ treatments. At harvest, colour of second‐ and third‐break mushrooms was significantly improved by all CaCl₂ treatments. This beneficial effect was more pronounced after 8 days of cold storage and during shelf‐life in sporophores treated with 0.35, 0.75 and 1.00% CaCl₂. No consistent correlation was found between Ca content and texture of fresh and stored mushrooms. However, although softer mushrooms were recorded at harvest in most CaCl₂‐irrigated crops, 0.25, 0.75 and 1.00% concentrations appeared to retard mushroom softening, promoting firmness at the 8th day of cold storage and during shelf‐life. © 2001 Society of Chemical Industry     

Influence of EDTA and citrate on thermal stability of whey protein stabilized oil-in-water emulsions containing calcium chloride

The influence of calcium ions and chelating agents on the thermal stability of model nutritional beverages was examined. Oil-in-water emulsions (6.94% (w/v) soybean oil, 0.35% (w/v) WPI, 0.02% (w/v) sodium azide, 20 mM Tris buffer, 0–10 mM CaCl₂, and 0–40 mM EDTA or citrate, pH 7.0) were stored at temperatures between 30 and 120 °C for 15 min. The particle size, particle charge, creaming stability, rheology, and free-calcium concentration of the emulsions were then measured. In the absence of chelating agents, appreciable droplet aggregation occurred in emulsions held at temperatures from 80 to 120 °C, which led to increased emulsion particle diameter, shear-thinning behavior, apparent viscosity, and creaming instability. Addition of chelating agents to the emulsions prior to heating decreased, but did not prevent, droplet aggregation in the emulsions. EDTA was more effective than citrate in decreasing droplet aggregation. Heat treatment increased the amount of chelating agents required to prevent droplet aggregation in the emulsions. Free-calcium concentration and droplet surface potential was independent of heat-treatment temperature, indicating that the performance of the chelating agents in binding calcium ions was not affected by the heat treatment. It was suggested that increased hydrophobic attractive interactions between the droplets occurred during heating, which induced droplet aggregation.     

The combined effects of fat content,calcium chloride,and coagulant concentration on the development of cheese curd structure

The effects of differing content levels of calcium chloride (approximately 200 and 400 μg Ca per 100 g milk protein) and of a microbial coagulant (3200 and 6400 μL per 100 L of milk; 950 IMCU (international milk coagulating units) mL⁻¹) on the coagulation of cows' milk with various fat levels (0.02–3.77%, w/w) was studied. Non-linear regression analysis was used to evaluate dynamic factors (lag time, t_lag; maximum coagulation rate, C_max; time for the maximum coagulation rate, t_max). Increasing fat content in the milk at constant calcium chloride and coagulant contents had no significant and clear effects on the t_lag, C_max, and t_max values. Increased levels of calcium chloride or microbial coagulant led to a significant decrease in t_lag and t_max, and conversely increased C_max. Therefore, milk fat content had no significant effect on gel development; however, levels of calcium chloride and coagulant significantly influenced gel structure.     

EFFECT OF CALCIUM CHLORIDE ON CHESTNUT

Chestnuts treated with calcium chloride (CaCl₂), which were stored in sand, survived after 80‐days dormancy stage. Calcium chloride stablilized the membrane, but it accelerated the decay of the chestnut. The main reason for the decay was that the stress of low oxygen content induced the production of active oxygen species, eg., H₂O₂ by analyzing the physiological indexes such as superoxide dismutase (SOD), catalase (CAT), malondialdehyde, vitamin C (Vc), damage rate and decay rate.