Effects of calcium chloride and calcium lactate applications with osmotic pretreatment on physicochemical aspects and consumer acceptances of dried papaya

This study explored the effects of calcium chloride (CaCl₂) and calcium lactate (Ca‐L) pretreatments prior to osmotic dehydration on physicochemical characteristics and consumer acceptance of dried papaya. Three different calcium concentrations [0.5, 1.5 and 2.5% (w/v)] were applied to samples before they were soaked in a 30 °Brix sucrose solution and subsequently dried at 70 °C. The results showed that the dried samples treated with calcium exhibited significantly lower moisture content, water activity, apparent density and shrinkage, while volume was higher when compared to the control. Calcium applications did not obviously influence sugar content of samples and maintained the quality of dried papaya in terms of colour and textural characteristics. Calcium chloride at 2.5% (w/v) was found to particularly impart undesirable bitterness to the dried papaya. In contrast, using 2.5% (w/v) Ca‐L provided the best acceptance scores. Thus, the use of Ca‐L could be an alternative to CaCl₂ in the pretreatment of fruits prior to drying as it offers improved quality.     

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.     

Biological Control of Rambutan Post-Harvest Anthracnose (Colleotrichum gloeosporioides) by Combined Treatment of Trichoderma harzianum-TrH40 Culture Filtrates and Calcium Salts

Trichoderma harzianum-TrH40 isolated from soil samples from rambutan (Nephelium lappaceum) orchards had antagonistic effects with combination of CaCl₂ salts on growth, activity, and infection of rambutan fruits by anthracnose (Colleotrichum gloeosporioides). Lower growth rate of spore germination, radial mycelial growth, and infectivity of anthracnose pathogen was observed at higher molar concentration of CaCl₂ by in vitro studies. Germination rate was 0.5%?when 1M CaCl₂ was combined with T. harzianum-TrH40 spore suspension. The disease incidence and severity of anthracnose were least on wounded fruits that had been dipped in a solution containing of 1,100 mg of CaCl₂ per liter and T. harzianum-TrH40, which contained 10⁶ spores/ml. Furthermore, disease incidence and severity with combined treatments were correlated significantly and effectively reduced infection in vivo in rambutan fruits.     

Hydrogen and Calcium Ion Concentrations Affect Volume of CO2 Puffed Diced Green Bell Peppers

Diced green bell peppers were soaked in a solution of hydrochloric acid or calcium chloride, air-dried to 50% moisture, held in CO₂ at 5.8 MPa for 1, 3 or 5 min, and puffed by abruptly releasing the CO₂ pressure. Treatment with 1% CaCl₂ increased the size of puffed-dried products as compared to a control; however, HCl treatments did not. The treatment with 1 or 2% CaCl₂ reduced shrinkage as compared to the control. The 1% CaCl₂ treatment may have increased the CO₂ saturation rate.     

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.     

Canning Quality Evaluation of Pinto and Navy Beans

Thermal processing of pinto and navy beans at 121.1°C for 16 or 14 min in a still retort gave similar sterilization value (F_o= 10) as the processing at 115.6°C for 45 min. The 121.1°C/16 or 14 min process produced beans with greater firmness than the 115.6°C/45 min process. The addition of CaCl₂ and EDTA improved firmness and color of canned beans. Calcium chloride also reduced clumping and splitting of the canned beans. Sensory evaluation showed that the acceptability of canned beans was reduced when CaCl₂ was increased up to 10 mM. High correlation between firmness and soluble pectin in various bean cultivars implied that soluble pectin content could be used as a parameter for screening bean cultivars with desirable firmness.     

Determination of total mercury in seafood by cold vapor-atomic absorption spectroscopy (CVAAS) after microwave decomposition

A method was developed for determination of total Hg in seafood using 10% w/v SnCl₂ · 2H₂O and continuous flow CVAAS after microwave decomposition in closed vessels. Seafoods were decomposed with 5 mL HNO₃ and 1 mL 1% w/v NaCl at 200 °C, transferred to polypropylene tubes containing 3.5 mL HCl, and diluted to 50 mL with H₂O. Standards were prepared in diluent containing 10% v/v HNO₃, 7% v/v HCl, and 0.02% w/v NaCl. Potential interference by 22 elements was evaluated. Interference by Se and Au was observed. Stability of standard solutions in HNO₃, HCl and NaCl was evaluated. Stabilizing effect of chloride was demonstrated. Results for six reference materials containing 0.0371–1.59 mg/kg Hg were 86–106% of certificate values. Concentrations in 11 varieties of seafood were 0.015–1.78 mg/kg. Average recoveries of inorganic and organic Hg added to seafood were 102% and 99%, respectively; average recoveries from fortified method blanks were 100% and 97%, respectively. The limits of quantitation were 0.0022 and 0.011 mg/kg in seafoods and reference materials, respectively.     

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.     

Water holding capacity of sodium-reduced chicken breast myofibrillar protein gel as affected by combined CaCl2 and high-pressure processing

The water holding capacity (WHC) of sodium-reduced (0.3 m sodium chloride, corresponding to the salt percentage (w/v) of 1.755%) myofibrillar protein (MP) gel in response to combined calcium chloride (CaCl₂, 20, 60, 100 mm ) and high-pressure processing (HPP, 200 MPa, 10 min) was investigated. The results showed that 200 MPa + 20 mm CaCl₂ synergistically increased the WHC of MP gel via reducing particle size of MP solutions, strengthening hydrogen-bonding and disulphide-bonding, promoting formation of β-sheet and uncoiling of α-helix, exposing tryptophan residues, enhancing hydrophobic interactions of aliphatic residues and forming a compact and continuous networked gel structure. However, high concentrations (≥60 mm ) of CaCl₂ could attenuate the enhancing effects of HPP on the WHC by inducing decreased hydrogen bonds, fewer tryptophan residues exposed and coarser and aggregated gel structures with large cavities. Therefore, a combined moderate HPP and low concentration of CaCl₂ is a potential alternative for developing sodium-reduced meat products.     

Improvements in Canned Lowbush Blueberry Quality

Individually quick frozen lowbush (wild) blueberries (Vaccinium angusrifolium) were canned with 0, 1500, or 3000 ppm calcium from chloride or lactate salts and 0, 0.25, or 0.50% citric acid in water. Physical and pH changes were measured at 0, 6, and 12 mo, and sensory evaluations were made at 3 and 9 mo post-canning. Calcium increased firmness and berry calcium content. Calcium chloride and citric acid reduced pH and increased hue angle and off-flavor; calcium lactate increased drained weight and pH but reduced hue. Response surface methodology predicted changes in calcium lactate-treated berries, but not CaCl₂-treated berries. Optimal conditions were 1200–1800 ppm calcium lactate at 3–6 mo storage.     

Water sorption and time-dependent crystallization behaviour of freeze-dried lactose-salt mixtures

Water sorption properties of freeze-dried lactose, lactose/CaCl₂, lactose/NaCl, lactose/MgCl₂, and lactose/KCl mixtures in their molar ratio of (9:1) were investigated. Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were used to model water sorption properties. Water is known to function as a plasticizer, depressing the glass transition and facilitating crystallization. Crystallization in the present study resulted in loss of sorbed water from lactose. The crystallization of pure lactose and lactose/salt mixtures was observed at RVP?44.0% within 24 h. At RVP?54.4% water contents were higher in lactose/CaCl₂ and lactose/MgCl₂ mixtures than in pure lactose, lactose/NaCl, and lactose/KCl.Water content in pure lactose after crystallization was ?5.0%, suggesting that lactose crystallized as a mixture of α-lactose monohydrate and various anhydrous forms of α/β-lactose crystals. Anhydrous lactose/CaCl₂ and lactose/MgCl₂ had higher glass transition temperatures than lactose, but other salts (NaCl and KCl) with lactose gave lower glass transition than amorphous lactose. It seems that bivalent salts in mixtures with lactose gave a higher T_g than smaller monovalent ions. Salts delayed lactose crystallization. The effect on lactose crystallization was highest with calcium chloride (CaCl₂) and lowest with potassium chloride (KCl). It seems that different salts interacted with lactose to different extents. For water sorption, GAB model gave a better fit than BET model. Water sorption and time-dependent crystallization properties of lactose/salt mixtures should be considered in manufacturing and storage of dairy-based dehydrated materials.     

Optimising deproteinisation methods and effect of deproteinisation on structural and functional characteristics of flaxseed gum

In the current study, deproteinisation rate (DPR) and carbohydrate loss ratio (CLR) in flaxseed gum (FSG) were compared as indexes by using four different deproteinised methods, that is sodium chloride (NaCl), trichloroacetic acid (TCA), hydrochloric acid (HCl) and calcium chloride (CaCl₂). In addition, the effect of deproteinisation on physicochemical, functional and structural characteristics (FTIR, ¹H NMR and SEM analysis) of deproteinised flaxseed gum (DFSG) was further examined. The results revealed that HCl and TCA methods had better ability of deproteinisation (97.83% and 96.21%) but resulted in higher CLR (27.66% and 24.19%), while CaCl₂ method excelled over the NaCl method in DPR (94.7% and 88.6%) and CLR (4.90% and 4.21%), respectively. Flaxseed gum showed significant functional properties even after deproteinisation and exhibited resolved resonances for both ring and anomeric protons in ¹H NMR spectra. The characteristic groups in FTIR spectra were retained after deproteinisation.     

Eggshell powder,a comparable or better source of calcium than purified calcium carbonate: piglet studies

Powdered chicken eggshells might be an interesting and widely available source of calcium. In two studies using piglets we determined the digestibility of calcium from different diets. The first study compared casein-based diets with CaCO₃ (CasCC) or eggshell powder (CasES). The second study compared soya protein isolate-based diets with CaCO₃ (SoyCC) or eggshell powder (SoyES). Diets were fed to groups of six piglets. Faeces were collected quantitatively. No adverse effects of eggshell powder were observed with regard to magnesium and crude fat digestibility. Calcium from eggshell powder was more digestible than calcium from purified CaCO₃. In the first study, digestibility coefficients for calcium were 66.9 (SD 7.9)% for CasCC and 71.3 (SD 3.8)% for CasES. In the second study, these coefficients were 46.7 (SD 8.6)% for SoyCC, and 65.9 (SD 3.7)% for SoyES, a significant difference. Our conclusion is that eggshell powder is, in the case of casein-based diets, as good a source of calcium as CaCO₃ and, in the case of soya protein-based diets, better than CaCO₃ for growing piglets. As the piglet model is considered to be representative for humans, chicken eggshell powder is also a promising source of calcium for human nutrition. © 1999 Society of Chemical Industry     

Vacuum Infusion of Citrus Pectinmethylesterase and Calcium Effects on Firmness of Peaches

Vacuum infiltration of Majestic peaches (Prunus persica) for 1 hr with a solution of Marsh grapefruit pectinmethylesterase (PME) containing 100 mg/L CaCl₂ significantly increased firmness of canned peaches. Mean firmness of peaches infused 2 hr and thermally processed was 13.9 J/Kg as compared to 3.2 J/kg for noninfused, processed controls. The calcium content increased from 278 to 432 mg/kg during 2 hr infusion of blanched peaches. Specific activity of PME in peach halves increased more than 20 fold after infusion.     

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.     

Effect of different pre-treatments and dehydration methods on quality characteristics and storage stability of tomato powder

Dehydration process was carried out for tomato slices of var. Avinash after giving different pre-treatments such as calcium chloride (CaCl₂), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl₂+KMS), and sodium chloride (NaCl). Untreated samples served as control. Solar drier and continuous conveyor (tunnel) drier were used for dehydration. Quality characteristics of tomato slices viz. moisture content, sugar, titratable acidity, lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning (NEB) as affected by dehydration process were studied. Storage study was also carried out for a period of 6 months for tomato powder packed into different types of packaging materials viz. metalized polyester (MP) film and low density polyethylene. Changes in lycopene content and NEB were estimated during storage at room temperature. Pre-treatment of 5 mm thickness of tomato slices with CaCl₂ in combination with KMS and drying using a tunnel drier with subsequent storage of product in MP bags was selected as the best process.     

A Laboratory and Field Study of the Relationship Between Calcium Sources and Browning in Apple Juice

Chloride ions added to freshly pressed apple juice at the rate of 0.2 mg/100 mL significantly slowed browning. Levels of chloride considerably higher than this were detected in juice produced from apples of the cultivar Northern Spy which had been sprayed with CaCl₂ (44.8 Kg/ha). Juice containing these chloride spray residues browned at a significantly slower rate than juice from apples off control trees. Chelated CaCl₂ sprays applied at considerably lower rates of chloride ion (13.6 and 27.2 Kg/ha of formulation containing 6.0% calcium and 10.1% chloride) and chelated Ca(NO₃)₂ (13.6 and 27.2 Kg/ha of formulation containing 6.0% calcium and 18.6% nitrate) did not significantly change the level of browning from that of the control.     

Effect of Calcium Salts on Susceptibility to Browning of Avocado Fruit

Fuerte avocados were dipped in 0.18M solutions of calcium chloride (CaCl₂·6H₂O) or calcium phosphate (CaHPO₄) or calcium arsenate [Cas(AsO₄)₂] or calcium nitrate [Ca(NO₃)₂·4H₂O] to determine whether these treatments had any effect on the browning components in avocados. It was found that calcium treatments suppressed both respiration and polyphenol oxidation and also reduced the content of total phenolics, leuco-anthocyanins, and flavonols. Of those calcium treatments used, calcium arsenate gave the best results.     

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.     

Mechanical and physical properties of calcium-treated gellan films

The physicochemical properties of Ca²⁺-treated gellan films plasticized with glycerol were investigated as a function of CaCl₂ concentration (0–20%, w/w) in an aqueous soaking solution. Films were examined based on their mechanical properties, water vapor permeability (WVP), swelling index (SI), thickness and opacity. The SI was lower for Ca²⁺-treated films relative to a control, however, above 13% (w/w) CaCl₂ no differences in SI were found. At 13% (w/w) CaCl₂, tensile and puncture strengths reached a maximum. Tensile elongation, puncture deformation, film thickness and WVP were lower for CaCl₂-treated films than untreated, however, all increased with CaCl₂ concentration. Opacity of gellan films increased with the Ca²⁺-treatment relative to the untreated film, however declined as CaCl₂ concentration increased. In general, Ca²⁺-treated gellan films were stronger, acted as better water vapor barriers, swelled less when in contact with water, and became less pliable and transparent.