Morais, Alcina M. M. B.

Rocha, Ada M. C. N.

English

Repositório Institucional da Universidade Católica Portuguesa

.USALEM, ISRAEL MARCH 26 - 31, 2000CC0)0FACTORS AFFECTING THE POST-CUTTING LIFE ANDQUALITY OF MINIMALLY PROCESSED PINEAPPLEMarrero. A and Kader, A.A.2nstituto Camino de Investigaciones Agntria.s La Laguna, Spain and2Pinnology Department, University of California. Davis. USA.amarrerotaficiarcanaria.esThe suitability of 'Chambaka' pineapple for fresh-cut processing wasinvestigated. Fruits were received via air freight from Hawaii and stored at10°C until processed. After peeling and coring the fruits, the pulp was slicedinto I -cm-thick wedges (about 8 g each), dipped into chlorinated water, andkept in jars under a humidified flow of air or the desired gas mixture.Temperature was the main factor influencing the duration of post-cuttinglife and the linal quality of the product. Post-cutting life ranged from over 2weeks at 0°C to only four days at 10°C. The end of viable storage wasdetected by a pronounced rise in respiration followed by an increase inethylene production rate. Peel tissue showed higher respiration and ethyleneproduction rates than pulp and core tissues. At temperatures between 0 and111°C no chilling injury was observed, although prolonged storage causedsome browning. No major changes were detected in soluble solids content.pl I or acidity olthe wedges during storage. Mylar film on polystyrene cupsallowed the accumulation up to 10% CO 2 and depletion down to 2% 02during a 9-day storage period at temperatures between 0 and 10°C. Oxygenconcentrations below 5% were associated with the development of off-odorsand flavors.SHELF LIFE OF MINIMAL PROCESSED PINEAPPLE FRUITPRODUCTSCorona. It} Manzano - Mendez., J. E l and This, it?'Posgrado de Horticulture, Decanato de Agronomist, UniversidadCentroccidental "Lisandro Alvarado" P.O. Box 815. Barquisimeto 3001,Lara, Venezuela S.A. e-mail: rcontwandisurlasarc2 Departament of Plant Production, Box 27, FIN-00014 University ofHelsinki, Finland.Nowadays, there is a tendency towards consumption of fresh or minimallyprocessed fruit and vegetable products free of additive applications, butprocessing technology needs to be improved. The aim of this investigationwas to study the minimal processing technique for pineapple products.Pineapple fruits (Ananas COMMIS L.) cv. Cayena Lisa, from Bobare regionin the Lara state, were washed with sodium hypochloride solution (25 ppm),peeled off and cut in slices, 1,5 cm thick. Fruit slices were put in plasticbags with an osmotic syrup solution (50% sucrose, citric acid 800 ppm,potassium sorbate 50 ppm) and blanched by immersion in hot water at 80°C for one minute. After cooling, the bags were thermosealed with orwithout vacuum application. The shelf life of the fruit products wasevaluated after for three weeks storage at 4 or 28° C. The products wereanalyzed for texture, colour, water activity (aw), pH, soluble solidconcentration (SSC) and microbiological quality. The quality performanceof the products stored under vacuum at 4° C, showed good appearance, andthe final values of other quality attributes were as follows: aw 0,938; SSC36% and pH 2 88.INFLUENCE OF CHEMICAL TREATMENT ONPOLYPHENOLOXIDASE ACTIVITY WHILERELATED TOCOLOUR CHANGES OF MINIMALLY PROCESSED'JONAGORED'APPLERoche , A.M.C.N. and Morais, A.M.M.B.Escola Superior de Biotecnologia, Universidade Catolica PortugueseRua Dr. Antonio Bernardino de Almeida, 4200 -072 Porto, Portugal(e-mail: amorais@esb.ucp.pt)Restrictions of sulfite usage for food preservation, associatedwithconsumer's concern about its safety, generated the need forsubstitutes. Ascorbicacid was found to be less effective than 502 incontrolling browning. Combinations of antibrowning agents havebeenused, aiming to enhance the effect of any single agentindividually. Citricacid has often been used in conjunction withascorbic add as a chemicalinhibitor of enzymatic browning.The aim of this work was to evaluate the influence of a 5 min-dipin 42.5mM ascorbic acid; 21.3 mM ascorbic acid + 34.0 mM citricacid; 14.2 mMascorbic acid + 22.7 mM calcium chloride + 12.0 mMcitric acid onpolyphenoloxidase activity and phenolic content offresh-cut apple (cv. Jonagored) during cold storage, and to lookforrelationship with enzymatic browning.A 92 %inhibition of PPO activity was achieved after 3 days at 49C bypreviously imerging apple cubes in the ascorbic acid dip. Colourchanges were correlated with the total phenolic content.Nocorrelation was found between PPO activity and colour or totalphenoliccontent of ascorbic acid - treated apple cubes.ACKNOWLEDGMENTSThis research wasfundedby a JNICT scholarship (Praxis XXI BD5365 / 95). The authorsacknowledge Estagffo Regional FruticulturaVitivivinicultura - Quintade Sergude, Felgueiras, Portugal.SENSORY AND MICROBIOLOGICAL CHANGES IN MINIMALLYPROCESSED CACTUS PEAR (Opuntia ficus indicts)Saenz, C.*, Berger,1-17, Galletti, La. and Coronado, F'.*Dept°. Agroindustria y Enologia and "Centro Estudios Postcosecha(CEPOC). Facultad de Ciencias Agronemicas. Universidad de Chile.Casilla 1004. Santiago, Chile. e-mail: csaenz@abello.dic.uchile.c1Cactus pears are difficult to peel due to the presence of spines. Theminimal processing could be an interesting way to increase theacceptability of this fruit. Changes in gas composition, sensory andmicrobiological characteristics during the storage of minimally processedcactus pear were studied. Cactus pear fruits were washed (200 ppm Cl2),manually peeled, treated or not with a citric acid solution (1%, 14°C, 10min), centrifuged (500 rpm), packed in BB4 (EVA) and PE perforated bagsand stored (4°C, 85% R.N.). Gas composition (% CO 2 and % 0.,); sensorycharacteristics (quality and acceptability; using 1-9 points scales) andmicrobiological count (bacteria, mold and yeast) were determined. Theexperimental design was completely randomized and the results wereanalyzed by ANOVA. The CO 2 percentage was 42.6 and 43.3 and the 02percentage was 0.79 and 0.8 at 14 days of storage in the BB4 bag, for thesamples with or without citric acid respectively. The treatment in PE bagspresented a 0.03% CO2 and 21.0% 02 in the same storage period. Thesensory characteristics remained constant during the storage period foralmost an the quality attributes; the acceptability shows differences with theimmersion treatment, causing a better acceptance for the fruit withoutimmersion and in 554 bags (7.1 points). The aerobic bacteria count was10' — 102 clu/g at the beginning of the storage period; after 14 days the PEbags presented 3 — 4 clu/g. The yeast and molds count was less than 10cfWg until 14 days of storage; the E. Coil count was less than 3 coug at theend of the storage period studied.-70-

Influence of chemical treatment on polyphenoloxidase activity while related to colour changes of minimally processed ‘Jonagored’ apple

https://repositorio.ucp.pt/bitstream/10400.14/5588/1/2000_ESB_Morais_Alcina-dig6.pdf

Influence of chemical treatment on polyphenoloxidase activity while related to colour changes of minimally processed ‘Jonagored’ apple

Abstract

Similar works

Full text

Available Versions

Repositório Institucional da Universidade Católica Portuguesa