Characterisation of odour‐active compounds in papaya (Carica papaya L.) wine

The volatile compounds of papaya wine were isolated by continuous solvent extraction and analysed by gas chromatography‐flame ionization detector and gas chromatography‐mass spectrometry. A total of 118 volatile constituents were detected, and ninety‐seven were positively identified. The composition of papaya wine included fifty‐three esters, twenty‐two alcohols, nine acids, seven phenols and derivatives, seven sulphur compounds, five lactones, five terpenes, three ketones, two aldehydes and five miscellaneous compounds. The aroma‐active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis and by odour activity values. Six odorants were considered as odour‐active volatiles: ethyl octanoate, (E)‐β‐damascenone, 3‐methylbutyl acetate, benzyl isohtiocyanate; ethyl hexanoate and ethyl butanoate.     

Phenolic and carotenoid profiles of papaya fruit (Carica papaya L.) and their contents under low temperature storage

BACKGROUND: Tropical fruits are rich in phenolic and carotenoid compounds, and these are associated with cultivar, pre‐ and postharvest handling factors. The aim of this work was to identify major phenolics and carotenoids in ‘Maradol’ papaya fruit and to investigate their response to storage temperature. RESULTS: Ferulic acid, caffeic acid and rutin were identified in ‘Maradol’ papaya fruit exocarp as the most abundant phenolic compounds, and lycopene, β‐cryptoxanthin and β‐carotene were identified in mesocarp as the major carotenoids. Ranges of contents of ferulic acid (1.33–1.62 g kg^?1 dry weight), caffeic acid (0.46–0.68 g kg^?1 dw) and rutin (0.10–0.16 g kg^?1 dw) were found in papaya fruit, which tend to decrease during ripening at 25 °C. Lycopene (0.0015 to 0.012 g kg^?1 fresh weight) and β‐cryptoxanthin (0.0031 to 0.0080 g kg^?1 fw) were found in fruits stored at 25 °C, which tend to increase during ripening. No significant differences in β‐carotene or rutin contents were observed in relation to storage temperature. CONCLUSION: Phenolics and carotenoids of ‘Maradol’ papaya were influenced by postharvest storage temperature with exception of β‐carotene and rutin. Ripe papaya stored at 25 °C had more carotenoids than those stored at 1 °C. Low (chilling) temperature (1 °C) negatively affected the content of major carotenoids, except β‐carotene, but preserved or increased ferulic and caffeic acids levels, as compared to high (safe) temperature (25 °C). Copyright © 2010 Society of Chemical Industry     

The storage and drying characteristics of papaya (Carica papaya L.) latex

A range of latex storage and air drying conditions were studied with regard to the proteolytic activity of the dried latex (‘crude papain’). The optimum drying temperature is between 50–55°C, activity losses on drying can be restricted to about 7% under these conditions. The activity of crude papain is the same if it is derived either from exuded latex or from that portion (about 20% of latex yield) which coagulates on the fruit surface on tapping. Latex storage at tropical ambient for 2–24 h prior to drying (with or without exposure to sunlight) causes maximum losses of about 20% in the proteolytic activity of the crude papain. Sodium chloride addition has an anti-coagulating effect on latex and accelerates the later stages of drying. Contrary to earlier reports, this causes a decreased activity in the product, which may be related to changes in latex pH. Addition of EDTA or sodium bisulphite, singly or in combination, protects the latex activity (increases of 20–25% relative to controls).     

Modelling the effect of temperature on respiration rate of fresh cut papaya (Carica papaya L.) fruits

A respiration rate (RR) model based on Peleg’s equation was developed for predicting RRs of fresh cut papaya. Respiration data for fresh cut papaya at 3/4 maturity were generated at temperatures 5, 10, 15, 20, 25 and 30°C using a closed system. RRs was found to be significantly influenced by storage temperature and increased from 0.021 to 0.289 mL[O₂]/kg·h and 0.063 to 0.393 mL[CO₂]/kg·h as a function of O₂ and CO₂ gas concentrations, respectively. Peleg’s constant K ₁ and K ₂ were obtained from linear regression analysis using GraphPad Prism 5.0 software and regression coefficients have good fit with values close to unity. The model was verified to assess the capability of its predictability of the RRs over the temperatures. There was good agreement with the experimentally estimated RRs. Information derived from the model can contribute in the design of successful modified atmospheric systems for storage of fresh cut papaya.     

THERMAL DESIGN PROCESS FOR ACIDIFIED CANNED PAPAYA (Carica papaya L.) PULP

Previous results showed that the heat resistant portion of pectinesterase in the acidified papaya pulp var. “formosa” presented greater thermal resistance than Cl. pasteurianum. Based on this, and determined F^7.8C_77C, a value of 12.3 min was calculated using the heat resistant portion of pectinesterase as the target for the process, and applying 1.7 decimal reduction of the activity of the heat resistant enzyme (98% inactivation). Using Shiga (1976) an empirical relationship and a heating time of 12.9 min in water bath at 97C was established for the process. Three processing tests were carried out under these conditions using 6 cans per test. The processing values varied from 12.33 to 12.75 min at 77C. Statistical analysis showed no significant difference between tests and among cans as well as test at the 0.05 and 0.01 α level. After processing the cans, gelatinization, activity of remaining enzyme and micro-organism growth were not detected. This shows that the process was able to inactivate the heat resistant portion of pectinesterase and kill the natural micro-flora present on the pulp. By considering the initial variation of the pectinesterase activity in the pulp and F^7.8C_77C - value of 16.7 min, a safety factor for the process was applied. This process was equivalent to 15 min of heating in water bath at 97C and corresponded to 2.3 decimal reductions in activity of heat resistant pectinesterase. An inoculation pack study was performed to verify the microbiological safety of such process. Each can of papaya pulp was inoculated with 1 mL of a 10⁴ spore/mL suspension of Cl. pasteurianum. Swelling of the cans, growth after subculturing and pectinesterase were not detected after incubation, showing that the pulp could be safely processed. The storage test showed no significant changes in the color, flavor, aroma and texture of the canned acidified papaya pulp.     

Inhibition of endive (Cichorium endivia L.) polyphenoloxidase by a Carica papaya latex preparation

When endive polyphenoloxidase (PPO) was incubated with a crude papaya latex extract, it rapidly lost its activity. Inactivation was ascribed to thermostable nonenzymatic factors of low molecular weight. These factors were partially purified by a two step protocol including gel filtration chromatography on Biogel P2 and ion exchange chromatography using DEAE Sephadex A25. The PPO-inactivation rate was first order, when either inactivating agent or proton concentration was evaluated. Inactivation could be partially reversed by CuSO₄, which suggested that the inactivating factor(s) bound to the copper site of the enzyme. On a more rapid time scale than inactivation, papaya latex extract acted also as a weak noncompetitive PPO inhibitor.     

Volatile acids in tropical fruits: cherimoya (Annona cherimolia, Mill.), guava (psidium guajava, L.), mango (Mangifera indica, L., var. Alphonso), papaya (Carica papaya, L.)

The volatile acids extracted by pentane/dichloromethane (2 + 1) from tropical fruit pulps were identified and determined by capillary gas chromatography (HRGC) and combined capillary gas chromatography-mass spectrometry using EI- and CI mode (HRGC-EI/CIMS). In cherimoya (A. cherimolia, Mill.) fruit pulp 47 acids were characterized; major compounds were hexanoic (3 mg/kg) and octanoic (1 mg/kg) acid. Fifty one acids were identified in guava (P. guajava, L.), 54 in mango (M, indica, L., var. Alphonso) and 56 in papaya (C. papaya, L.). (E)-cinnamoic acid (0.4 mg/kg) and (Z)-3-hexenoic acid (0.2 mg/kg) were determined as major constituents in guava; in mango 5-hydroxy-(Z)-7-decenoic acid (2 mg/kg) and 3-hydroxyoctanoic acid (1.1 mg/kg) and in papaya pulp butanoic acid (1.2 mg/kg) were established as major constituents.     

Chemical composition of papaya (Carica papaya) seeds

Defatted and undefatted seeds of papaya (Carica papaya) were analyzed for proximate composition, some toxicants, sugar composition, mineral content, physico-chemical properties of the seed oil and the fatty acid spectrum of the seed oil. The seed is a rich source of proteins (27·8% undefatted, 44·4% defatted), lipids (28·3% undefatted) and crude fibre (22·6% undefatted, 31·8% defatted). Of the toxicants estimated, glucosinolates occur in the highest proportion. The seed is low in free monosaccharides. Sucrose is the predominant sugar (75·0% of total sugars). Mineral content is generally low. However, Ca and P occur in appreciable quantities (17 340 μg/g and 10 250 μ/g, respectively). The seed oil is low in iodine value (74·8), free fatty acids (0·94%) and carotene (0·02 μg/g). The major fatty acid is C18:1 (79·1%).     

Development and comparison of multivariate respiration models for fresh papaya (Carica papaya L.) based on regression method and artificial neural network

Respiration modelling is the fundamental of the packaging and storage of fresh fruit and vegetables. Previous model of respiration rate accounted for external forcing from temperature and modified atmosphere but did not attempt to predict internally generated natural variability such as maturity. We present two types of respiration models here that predict the respiration rate of fresh papaya in response to changes of temperature, CO₂/O₂ concentrations and maturity as well. These two models were separately developed using a quadratic polynomial with four parameters and fifteen coefficients and using an artificial neural network (ANN) model with 4-15-2 architecture trained by Levenberg–Marquardt algorithm, in which the maturity of papaya covers skin yellowing from 10 to 90% and the temperatures vary over 10–30 °C. Comparison between the two types of respiration models shows a predictive superiority of the ANN-based model over the regressive one, demonstrating that the use of ANN technique can provide a reliable and effective approach to describe papaya’s respiration rate as a function of multivariate influencing factors.     

Solar drying characteristics of papaya (Carica papaya) latex

Dripped, congealed and a mixture of dripped and congealed papaya latexes of varying charge sizes were dried in a rock-bed solar dryer over a temperature range of 40–60°C. The time taken for the fresh latex to dry from an initial moisture content of between 73 and 80% (wet basis) to an equilibrium moisture content of between 6 and 8% varied from about 1·5 to 36 h depending upon the charge size. The latex, whether dripped or congealed, dried as pale yellow flakes which could easily be powdered and had a proteolytic activity slightly higher than that of the fresh latex.     

Aroma compounds in fresh and dried mango fruit (Mangifera indica L. cv. Kent): impact of drying on volatile composition

Volatile compounds from fresh and dried mango were extracted by the solvent‐assisted flavour evaporation (SAFE) technique and analysed by GC‐MS. Forty‐one and fifty five volatile compounds were identified in fresh and dried mango, respectively. Monoterpenes, followed by sesquiterpenes, lactones and alcohols were the major compounds. Drying induced substantial losses of several compounds. The total amount of volatiles decreased by about 59%. These losses could be mainly attributed to the evaporation of the volatiles during drying, the extent of which seemed to increase with the hydrophobicity and Henry's law constant of the compounds. However, new compounds appeared and enrichment of some compounds was observed after drying. Limonene, β‐myrcene, δ‐3‐carene, β‐caryophyllene, γ‐butyrolactone and 3‐methylbutyl butanoate were found to be flavour contributors in both products on the basis of the odour activity values (OAVs). Mesifuran displayed high OAV only in fresh fruit while hexanal and heptanal only in dried mango.     

Carotenoids in yellow‐ and red‐fleshed papaya (Carica papaya L)

Vitamin A deficiency is a disorder of public health importance in Sri Lanka. A recent national survey revealed that 36% of preschool children in Sri Lanka have vitamin A deficiency (serum retinol <0.2 µg ml^?1). In view of its well‐established association with child morbidity and mortality, this is a reason for concern. One of the main fruits which has been recommended for prevention of vitamin A deficiency in Sri Lanka is papaya (Carica papaya L). In this study the carotenoid profiles of yellow‐ and red‐fleshed papaya were analysed by medium‐pressure liquid chromatography (MPLC) and UV‐vis spectrophotometry. A section of yellow‐fleshed papaya showed small carotenoid globules dispersed all over the cell, whereas in red‐fleshed papaya the carotenoids were accumulated in one large globule. The major carotenoids of yellow‐fleshed papaya were the provitamin A carotenoids β‐carotene (1.4 ± 0.4 µg g^?1 dry weight (DW)) and β‐cryptoxanthin (15.4 ± 3.3 µg g^?1 DW) and the non‐provitamin A carotenoid ζ‐carotene (15.1 ± 3.4 µg g^?1 DW), corresponding theoretically to 1516 ± 342 µg kg^?1 DW mean retinol equivalent (RE). Red‐fleshed papaya contained the provitamin A carotenoids β‐carotene (7.0 ± 0.7 µg g^?1 DW), β‐cryptoxanthin (16.9 ± 2.9 µg g^?1 DW) and β‐carotene‐5,6‐epoxide (2.9 ± 0.6 µg g^?1 DW), and the non‐provitamin A carotenoids lycopene (11.5 ± 1.8 µg g^?1 DW) and ζ‐carotene (9.9 ± 1.1 µg g^?1 DW), corresponding theoretically to 2815 ± 305 µg kg^?1 DW mean RE. Thus the carotenoid profile and organisation of carotenoids in the cell differ in the two varieties of papaya. This study demonstrates that carotenoids can be successfully separated, identified and quantified using the novel technique of MPLC. Copyright © 2003 Society of Chemical Industry     

Stability of carotenoids in freeze dried papaya (Carica papaya)

Effect of water activity ( a _w) and storage temperature on the degradation of carotenoids in relation to keeping quality of freeze dried papaya is reported. Carotenoids were found to be most stable at 0.33 a _w and both below and above this level their rate of destruction was higher. Above 0.40 a _w browning limited the storage life. Freeze dried papaya has maximum stability between 0.22-0.33 a _w.     

Mineral composition of the papaya (Carica papaya variety sunrise) from Tenerife island

In this study we have determined the contents of macroelements (Na, K, Ca, Mg and P) and microelements (Fe, Cu, Zn, Mn and B) in papaya samples (Carica papaya) obtained and consumed on the island of Tenerife, Canary Islands. The analysis shows the existence of significant differences in mineral content in the papaya samples. The papaya coming from MercaTenerife (wholesaler) presents higher K, P and Mn concentration levels than the papaya coming from the South Area of Tenerife. On the other hand, Na concentration levels are higher in the samples coming from the South Area of the island. There are differences between the mineral contents of this fruit shown in some food composition data tables and those analyzed in this work. The former are lower in Na, K, Ca and higher in Fe. In the same way, it is appreciated that the levels of Na concentration found in this work are greater than those found by other authors, and lower in Fe. When we compare the results obtained in this work and the recommended daily intakes or daily estimated demands of mineral elements proposed by different institutions or authors we realize that papaya is an important source of certain mineral elements, mainly K, Mg and B.     

Thermal Diffusivity of Papaya Fruit (Carica papaya L., Var. Solo)

The thermal diffusivity of papaya pulp is measured to be 1.52 × 10^-3 cm²/s and found to be in agreement with the value predicted by the Riedel equation within the uncertainty of the measurement. The thermal diffusivity of papaya seeds is measured to be 1.60 × 10^-3 cm²/s.     

Volatile compounds from pitanga fruit (Eugenia uniflora L.)

Extracts from pitanga leaves are considered to be effective against many diseases, and are therefore used in popular Brazilian medicines. In this study, the volatile constituents of pitanga fruits (Eugenia uniflora L.) were trapped on to Porapak-Q and eluted with ethyl acetate, and the chemical composition of the extract was analyzed by gas chromatography and gas chromatography/mass spectrometry. Fifty-four compounds were detected, and twenty-nine of those were identified by close matches with standard MS spectra. Monoterpenes (75.3% in mass) were found to comprise the largest class of the pitanga fruit volatiles, including trans-β-ocimene (36.2%), cis-ocimene (13.4%), the isomeric β-ocimene (15.4%) and β-pinene (10.3%). Several known therapeutic constituents of pitanga leaf extract, such as selina-1,3,7(11)-trien-8-one (the major constituent) were also found to be present in the fruit volatile extract, suggesting that the fruit may display therapeutic properties similar to those of the leaf extract.