Made available in DSpace on 2014-08-20T13:42:05Z (GMT). No. of bitstreams: 1 Tese_Cristina_Simoes_da_Costa.pdf: 676580 bytes, checksum: 3d29b81ccb9b1d19211d238ccd303fe3 (MD5) Previous issue date: 2009-07-30 / Strawberry is a highly perishable fruit, presenting a post-harvest shelf life relatively short due to physiologic changes and incidence of fungal decay, which limitate its fresh commercialization. Chitosan based edible coating are a good alternative on controlling post harvest changes associated do strawberry decay. This work was divided in two experiments. In first article, the application of chitosan edible coatings added of calcium and fat acid to promote preservation of the quality of strawberry cv. Aromas during refrigerated storage. Three coatings were studied: chitosan + calcium chloridre (QC), . chitosan + calcium chloride + oleic acid (QCAO), and chitosan + calcium chloride + stearic acid (QCAE). After coatings were applied, the fruits were stored at + 2°C e 75 ± 5%HR for 10 days. Firmness, pH, titratable acidity, content of soluble solids and, color weren t affected significantly at the end of storage, and no differences between treatment were observed. Coating affected significantly fungal decay on QC coated fruits when compared to non coated fruits, promoting 83%. Fruits that received QC or QCAE coating obtained same acceptability of control fruits. In the second article, the ability of chitosan edible coating, added of calcium and/or ascorbic acid to maintain strawberry post-harvest quality under refrigerated (0°C) and atmospheric (25ºC) storage was evaluated. Four coatings were studied: chitosan (Q); chitosan + calcium chloridre (QC), chitosan + ascorbic acid (QA), and chitosan + calcium chloride + ascorbic acid (QCA). After coatings were applied, the fruits were stored for 15 days at 0 + 2°C e 75 ± 5%HR (refrigerated) and for 7 days at 25ºC + 2ºC (atmospheric). Firmness, pH, titratable acidity, content of soluble solids and, color weren t affected significantly at the end of storage, and no differences between treatment were observed. On refrigerated condition, chitosan coatings promoted the maintenance of titrable acidity, reduction of loss of firmness and of fungal decay, which was completely inhibited on the fruits covered with QA and QC until the twelve day. Soluble solids content, pH, color (L*, C*, h*), anthocyanins content and phenolic compounds content weren´t affected by coating. On the strawberry stored under atmospheric temperature, coatings promoted retention of firmness and controlled fungal decay, showing no effects on the other attributes evaluated. In general, post-harvest application of chitosan based edible coatings preserve strawberry quality during storage. Incorporation of ascorbic acid or calcium chloride on coating promotes additional gain on the control of fungal decay, being observed a higher acceptability of coatings containing ascorbic acid. The employ of this coating can extend the shelf life of refrigerated or atmospheric stored strawberry until 12 and 3 days, respectively. / O morango é um fruto altamente perecível, apresentando período de conservação pós-colheita relativamente curto em virtude de alterações fisiológicas e incidência de podridão fúngica, o que limita sua comercialização in natura. As coberturas comestíves à base de quitosana tem-se mostrado como alternativas no controle das alterações pós-colheita responsáveis pela deterioração do morango. Este trabalho foi dividido em dois ensaios experimentais. No primeiro artigo, avaliou-se a aplicação de coberturas comestíveis à base de quitosana contendo cálcio e ácidos graxos para promover a manutenção da qualidade pós-colheita de morangos cv. Aromas durante o armazenamento refrigerado. Três coberturas foram estudadas: quitosana + cloreto de cálcio (QC); quitosana + cloreto de cálcio + ácido oléico (QCAO); quitosana + cloreto de cálcio + ácido esteárico (QCAE). Após aplicação das coberturas, os frutos foram mantidos por 10 dias sob condições de 0+2°C e 75+5%UR. A firmeza, o pH, a acidez titulável, o conteúdo de sólidos solúveis e a cor não apresentaram variação significativa ao final do armazenamento, não sendo verificada diferença entre os tratamentos quando comparados ao controle. A cobertura apresentou efeito significativo na redução da podridão fúngica dos frutos cobertos com QC, verificando-se uma redução de 83%. Os frutos que receberam as coberturas QC ou QCAE apresentaram mesma aceitação que os frutos controle. No segundo artigo, avaliou-se o efeito de coberturas comestíveis à base de quitosana, combinada ou não com cálcio e ácido ascórbico, na manutenção da qualidade pós-colheita de morangos durante o armazenamento refrigerado (0°C) e sob temperatura ambiente (25°C). Quatro coberturas foram estudadas: quitosana (Q); quitosana + cloreto de cálcio (QC); quitosana + ácido ascórbico (QA) e quitosana + cloreto de cálcio + ácido ascórbico (QCA). Após aplicação das coberturas, os frutos foram mantidos por 15 dias, a 0+2°C e 75+5%UR (refrigerado) e à 25°C + 2ºC (ambiente) durante 7 dias. Nas amostras refrigeradas, a utilização de coberturas promoveu manutenção da Lacidez titulável, redução de perda de firmeza e do desenvolvimento fúngico, sendo este completamente inibido nos frutos cobertos com QA e QC até o décimo segundo dia de armazenamento. O pH, o conteúdo de sólidos solúveis, a cor (L*, C* e h*), o conteúdo de antocianinas e o de compostos fenólicos não sofreram influência da aplicação da cobertura. Nos frutos armazenados à temperatura ambiente, foi verificado o efeito da cobertura na manutenção da firmeza, e no controle do desenvolvimento fúngico, não sendo observado efeito sobre a perda de massa e demais parâmetros estudados. De forma geral, pode-se concluir que a aplicação pós-colheita de coberturas à base de quitosana em morangos preserva sua qualidade durante o armazenamento. A incorporação de ácido ascórbico ou cloreto de cálcio na cobertura possibilita ganho adicional no controle do desenvolvimento fúngico, obtendo-se maior aceitação para as coberturas contendo ácido ascórbico. O uso dessa cobertura permite estender a vida útil de morangos armazenados sob refrigeração e à temperatura ambiente, por até doze e três dias, respectivamente.

In the last years, the edible packaging has been gaining popularity due to the potential usage as the packaging for food instead of synthetic materials. The edible packaging can positively affect the packaged food by the active properties or due to its intelligent properties can monitor the changes in food. In theory, the legislation about the packaging of food and edible packaging was described. The substances for edible films preparation and additives, which can improve the properties of the edible films, were described too. In this part, the undesirable microorganisms occur in food and the chapters about active and intelligent properties of the edible films were summarized. The main aim of the thesis was the practical preparation of edible packaging/films made from furcellaran, gelatin hydrolysate with the addition of water dried or fresh rosemary extracts in concentrations 5 %, 10 %, and 20 %. In the experimental part, the physical analysis was done – textural parameters such as tensile strength and elongation at break, water content, and thickness. In the chemical analysis the total polyphenols content, determination of polyphenols by HPLC, antioxidant activity, optical properties and antimicrobial activity of the prepared edible films were done. There were found out, that the total polyphenols content and antioxidant activity were the highest in the 20%DR (TPC: 6,79 ± 0,06 mg gallic acid/g; DPPH: 87,84 ± 0,07 %). Also, the 20%DR and 20%FR changed color in different pH (3 and 12). The antimicrobial activity was negative. The thesis showed that the addition of natural extracts to edible films can increase the polyphenols content and they can also work as the UV protector.

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