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.     

Effect of calcium chloride on mechanical properties and microbiological characteristics of cv. Conservolea naturally black olives fermented at different sodium chloride levels

The effect of calcium chloride (CaCl₂)(5 gL^?1) and sodium chloride (NaCl) concentration (40, 60 and 8 gL^?1) on the microbiological and mechanical properties of naturally black olives of cv. Conservolea in brines was studied. In 40 and 60 g L^?1 brines the growth of lactic acid bacteria was favoured over that of yeasts, resulting in rather complete lactic acid fermentation as indicated by high free acidity (9.8–11.5 g lactic acid L^?1) and low pH (3.7–3.8). At 80 g L^?1 brine, yeasts were the dominant members of the microflora, rendering a product with lower acidity (8 g lactic acid L^?1) and higher pH (4.3–4.5). In the presence of CaCl₂ there was a consistent increase in the depth of the peripheral region in which cell wall breakage occurred. When cells separated, perforated walls were observed at sites associated with plasmodesmata. The flesh was strongest and stiffest when CaCl₂ was added to olives treated with 40 g L^?1 brine, consistent with cell wall breakage being the predominant mode of failure. The only observed effect on the mechanical properties of the skin was a stiffening at 60 g L^?1 brine on addition of CaCl₂. Copyright © 2007 Society of Chemical Industry     

Effect of processing on the texture and structure of raspberry (cv. Heritage) and blackberry (cv. Thornfree)

This paper reports separate studies of the effect of pre-treatments (CaCl₂, low methoxyl pectin (LMP), and combined solutions) and the effect of freezing method (at four different rates) and thawing mode (at two different rates) on objective parameters, structure and sensory characteristics of fresh raspberries and blackberries. After that, the effect of a complete freezing process combining the best pre-treatments with the best freezing/thawing conditions found for each fruit was investigated. Kramer Shear Cell (KSC), back extrusion, compression and multiple penetration tests were used to measure fruit texture objectively. For calcium and LMP pre-treatments, which were applied separately, texture parameters were significantly higher in samples treated at the highest concentrations (100 mM of CaCl₂ for both fruits and 0.3 and 3% of LMP for raspberry and blackberry, respectively) compared to fresh controls. Blackberry structure was more susceptible than raspberry structure to the effect of pre-treatments. For the combined pre-treatments, the highest texture parameters were found in the samples treated with CaCl₂ (100 mM) and LMP (0.1%) in the case of raspberries and CaCl₂ (100 mM) and LMP (3%) in the case of blackberries. Combined pre-treatment did not increase firmness with respect to that of samples treated only with calcium, which indicates that CaCl₂ preserved the raspberry structure more efficiently during processing. Fruits frozen by forced convection with liquid nitrogen vapour at –40 °C were significantly firmer. Raspberries should be thawed at 5 °C, whereas blackberries may be thawed at room temperature. Sensory analysis showed that the blackberry structure was more resistant to freezing. In both fruits, over the complete process parameter values were again highest in the samples treated with 100 mM CaCl₂, applied either separately or in combination with LMP. In raspberry, panellists detected no significant differences between sensory texture parameters of the different samples, and in blackberry, panellists found no significant differences between any of the sensory characteristics. Multiple penetration maximum force (F _MP) was the parameter that best expressed product firmness for both fresh and frozen raspberries, whereas compression slope (S _C) best reflected changes in blackberries. SEM mainly corroborated results from objective texture parameters.     

Enhancing disease resistance in harvested mango (Mangifera indica L. cv. ‘Matisu’) fruit by salicylic acid

To learn how salicylic acid (SA) may affect disease resistance in mango, mango fruit (Mangifera indica L. cv. ‘Matisu’) were treated with 1 mmol L^?1 SA solution under vacuum infiltration for 2 min at a low pressure (?80 kPa) and for an additional 10 min at air pressure. The fruit were inoculated with anthracnose (Colletotichum gloeosporioides Penz.) spore suspension (1 × 10⁴ CFU mL^?1) and incubated at 13 °C, 85–95% RH. Disease incidence and lesion diameter in/on the SA‐treated fruit were 37.5% and 20.9% lower than that in/on control fruit on the 4th day of incubation. The study further showed that activities of defensive enzymes in the fruit were significantly enhanced by SA treatment. The activity of phenylalanine ammonia‐lyase (PAL) and β‐1,3‐glucanase in the SA‐treated fruit was over 6‐ or 0.9‐fold higher than that in control fruit on the 4th day after the fruit being treated with SA, respectively. Level of hydrogen peroxide (H₂O₂) or superoxide radicals (O₂^?) generation rate in SA‐treated fruit was 22.3% or 79.4% higher than that in controls on the 8th day after the fruit being treated with SA, respectively. These results suggested that PAL and β‐1,3‐glucanase, as well as H₂O₂ or O₂^?, may be involved in the enhancement of disease resistance in mango fruit. Copyright © 2006 Society of Chemical Industry     

Effect of calcium on the storage life of oro (Antiaris africana)

The effects of calcium on the ascorbic acid, chlorophyll, titratable acidity and texture (firmness) of stored oro (Antiaris africana (Mill)) friuits (average weight 100 g ) were studied. Three groups of the fruits were dipped in 20 g litre^?1, 40 g litre^?1 CaCl₂ solutions and deionised water respectively for I0 min. The fourth group, which was untreated, served as the control and was also packaged in heat-sealed cellophane bags. The fruits were displaced and stored at ambient temperature (28 ± 2°C). The calciumtreated fruits which kept better were firmer and had a slight colour change (chlorophyll) which also produced a progressive increase in ascorbic acid level during storage. The titratable acidity of the fruits did not fluctuate as signijcantly as that of the untreated (control) fruits.     

The labile pool of manganese in soil: Comparison of E and L value measurements with extraction methods

The size of the manganese labile pools of three sandy soils from south east Scotland with a history of Mn deficiency was investigated by four methods: extraction with CaCl₂; extraction with DTPA; E-value determination by exchange with ⁵⁴Mn; and L-value determination using barley as the test crop. There was little agreement between the methods. The L-values varied with the period of plant growth and with soil bulk density but greatly exceeded the E-values, which in turn were about twice the quantities obtained by prolonged extraction with CaCl₂ and an order of magnitude greater than the quantities extracted after 1 h with CaCl₂-DTPA extraction gave values three to six times those obtained with CaCl₂. Extractable Mn increased dramatically after prolonged air drying, indicating the need for standardisation of both pre-extraction conditions and extraction times when comparing the Mn availability of different soils.     

Study on the efficiency of ethylene scavengers on the maintenance of postharvest quality of tomato fruit

The objectives of this study were to achieve the best level of each ethylene scavenger and evaluate the effect of selected levels of treatments on some quality traits of tomato during storage. Tomato fruits were subjected to four levels of treatments: palladium-promoted nano zeolite, KMnO₄-promoted nano zeolite, 1-MCP, CaCl₂, salicylic acid (SA) and UV-C. The sampling was done at 0, 7th, 14th, 21st, 28th and 35th days of cold storage. The results showed that palladium-promoted nano zeolite 5%, KMnO₄-promoted nano zeolite 20%, 1-MCP 30 ppm, CaCl₂ 2%, SA 1% and UV-C 15 min levels had the most ethylene scavenging function. Effectiveness of the treatments in ethylene scavenging was in the order: palladium?>?KMnO₄?>?1-MCP?>?SA?=?CaCl₂?>?UV-C. The palladium-promoted nano zeolite 5% had more positive effects on phenol content, polygalacturonase activity, lycopene content, fruit firmness and weight loss, and UV-C 15 min had effect on decay severity as compared to the other treatments. Overall, palladium-promoted nano zeolite 5% could be considered not only as favorable tool in tomato shelf life extension but also in preservation of quality characteristics of tomato fruits during storage. Moreover, the UV-C 15 min treatment could be an effective method for reducing decay severity and maintaining postharvest quality of tomato fruits.     

Fermentation profiles of Manzanilla-Aloreña cracked green table olives in different chloride salt mixtures

NaCl plays an important role in table olive processing affecting the flavour and microbiological stability of the final product. However, consumers demand foods low in sodium, which makes necessary to decrease levels of this mineral in fruits. In this work, the effects of diverse mixtures of NaCl, CaCl₂ and KCl on the fermentation profiles of cracked directly brined Manzanilla-Aloreña olives, were studied by means of response surface methodology based in a simplex lattice mixture design with constrains. All salt combinations led to lactic acid processes. The growth of Enterobacteriaceae populations was always limited and partially inhibited by the presence of CaCl₂. Only time to reach half maximum populations and decline rates of yeasts, which were higher as concentrations of NaCl or KCl increased, were affected, and correspondingly modelled, as a function of salt mixtures. However, lactic acid bacteria growth parameters could not be related to initial environmental conditions. They had a longer lag phase, slower growth and higher population levels than yeasts. Overall, the presence of CaCl₂ led to a slower Enterobacteriaceae and lactic acid bacteria growth than the traditional NaCl brine but to higher yeast activity. The presence of CaCl₂ in the fermentation brines also led to higher water activity, lower pH and combined acidity as well as a faster acidification while NaCl and KCl had fairly similar behaviours. Apparently, NaCl may be substituted in diverse proportions with KCl or CaCl₂ without substantially disturbing water activity or the usual fermentation profiles while producing olives with lower salt content.     

采后番木瓜果实炭疽病病原菌分离鉴定及其拮抗菌的筛选

从采后发病番木瓜果实上分离炭疽病的病原菌,同时采用平板对峙法和滤纸片法从番木瓜果园土壤中筛选得到炭疽菌的拮抗菌W-2。通过形态学和分子生物学分别鉴定了病原菌和拮抗菌相关种属,并测试了拮抗菌W-2的拮抗活性。结果表明:番木瓜炭疽病病原菌鉴定为番木瓜炭疽菌Glomerella magna,拮抗菌W-2为萎缩芽孢杆菌(Bacillus atrophaeus)。拮抗菌W-2能够引起Glomerella magna菌丝体膨大和孢子畸形,且W-2浓度为1×108 CFU/mL时,对菌丝生长抑制作用最强,浓度为1×108和1×109 CFU/mL时,对孢子萌发的抑制作用最为显著(P<0.05)。活体生防实验表明,浓度为1×108 CFU/mL的W-2菌悬液处理能够有效控制番木瓜果实炭疽病病斑的扩展,并显著降低果实的发病率(P<0.05)。     

Enhancing disease resistance in peach fruit with methyl jasmonate

BACKGROUND: Peaches are susceptible to microbial decay during postharvest distribution at ambient temperature. To search for effective alternatives to currently used fungicides for disease control, in this study the effect of methyl jasmonate (MeJA) on disease resistance and fruit decay of peaches after harvest in response to pathogen attack was investigated. RESULTS: Freshly harvested peaches were treated with 1 µmol L^?1 MeJA vapour at 20 °C for 24 h. At 0, 12, 24 and 36 h after this treatment, both treated and untreated fruits were artificially wounded and inoculated with Penicillium expansum, Botrytis cinerea or Rhizopus stolonifer spore suspension (1 × 10⁵ spores mL^?1) and then incubated at 20 °C for 6 days. MeJA treatment significantly reduced the postharvest diseases. Incubation for 12 h was the optimal length of time after MeJA treatment, resulting in the lowest disease incidence and lesion diameter for all pathogens. The activities of defence enzymes including chitinase, β‐1,3‐glucanase, phenylalanine ammonia‐lyase, polyphenol oxidase and peroxidase were enhanced by MeJA treatment, and the level of total phenolics in MeJA‐treated fruit was also higher than that in control fruit. In addition, MeJA affected hydrogen peroxide (H₂O₂)‐metabolising enzymes such as superoxide dismutase, catalase and ascorbate peroxidase and induced a higher level of H₂O₂ during incubation, which might serve as a signal to induce resistance against P. expansum. CONCLUSION: MeJA was effective in reducing decay and might enhance disease resistance in peach fruit by increasing levels of antipathogenic proteins and antimicrobial phenolic compounds. Copyright © 2009 Society of Chemical Industry