Fresh-cut fruit is among the most highly perishable food product, characterized by short shelf-life (5-7 days), affected by microbiological spoilage and reactions caused by the presence of oxygen, such as enzymatic browning or oxidation reactions. The high added value of this product may justify the use of expensive storage solutions. Several methods exist to preserve ready-to-eat fruit, like dipping in natural or synthetic substances, or the use of active packaging and modified atmosphere packaging. These storage solutions affect differently on the final costs of the product but also on the preservation of the fruit, and on the maintenance of its quality during shelf-life. In the present doctoral period it was decided to address some factors that influence fresh-cut fruit quality during storage, particularly, enzymatic browning, the pomological decay and microbiological spoilage. To limit these factors it is chosen to use different solutions: the dipping in natural extracts, the active packaging based on natural antioxidants and antimicrobials compounds, as well as the development of a flexible high barrier film, by cellulose nanocrystals, for possible applications on fresh-cut fruit stored under modified atmosphere. The results we obtained on fresh-cut peach or pineapple, gave us many indications. The dipping into plant extract solutions allows a good maintenance of qualitative characteristics though lower than the active packaging. Furthermore, the use of the dipping technique exposes the product to water and air for excessive time, influencing the storage, when compared to the other used storage methods. Concerning the high barrier material developed we obtained very promising results, both for a longer shelf-life, and for a higher sustainability. The active packaging was the most efficient technique both in terms of costs, employing low cost substances, and in terms of automation of the process, as well as the quality preservation. Active packaging allows, in fact, to have longer lasting effect over the time, not exhausting its efficacy in the first days of storage but carrying out its role during all the shelf-life and assuming its minimum increase. In particular, we developed the technique of "layer-by-layer" that resulted very interesting in terms of antioxidant and antimicrobial effect, and a high device customization. In fact, this device can be applied to many types of fresh food, as well as on longer shelf-life food, giving the possibility to obtain a controlled release over the time. Indeed, it is suitable for an easy scale-up production.
La frutta di IV gamma è un prodotto altamente deperibile, con una shelf-life molto corta (5-7 giorni) influenzata dalle numerose variabili che entrano in gioco accelerando la senescenza del prodotto. Il suo alto valore aggiunto può giustificare l’utilizzo di soluzioni di conservazione più o meno costose. I metodi attualmente esistenti sono numerosi, spaziano dal dipping in sostanze naturali o sintetiche, all’utilizzo di packaging attivi, all’impiego di atmosfere modificate, ecc. Queste metodiche di conservazione incidono in maniera diversa sui costi finali del prodotto ma soprattutto sulla conservazione dello stesso e sul mantenimento della sua qualità lungo tutto il periodo di shelf-life. Durante il periodo di Dottorato si è scelto di intervenire su alcuni fattori che influenzano la qualità del prodotto durante il periodo di conservazione, in particolare l’imbrunimento enzimatico, il decadimento pomologico e il deterioramento microbiologico. Per limitare questi fattori si è scelto di utilizzare diverse soluzioni: il dipping in estratti naturali, l’active packaging a base di antiossidanti e antimicrobici di origine naturale, nonché la messa a punto di un film flessibile ad alta barriera, con utilizzo di nanocristalli di cellulosa, per possibili applicazioni di frutta di IV gamma in atmosfera modificata. I risultati ottenuti, applicando le diverse soluzioni proposte su pesche o su ananas, hanno fornito numerose indicazioni. Il dipping in soluzioni con estratti di piante permettono una buona tenuta delle caratteristiche qualitative, tuttavia inferiore all’impiego degli active packaging. Inoltre, l’utilizzo della tecnica del dipping espone per tempi eccessivi il prodotto all’acqua e all’aria, influenzandone la conservazione, se paragonata alle altre soluzioni impiegate. Riguardo il film flessibile ad alta barriera sviluppato, I risultati ottenuti sono molto promettenti sia per un’applicazione su prodotti caratterizzati da un’elevata shelf-life, sia per l’elevata sostenibilità del materiale di confezionamento. L’active packaging è la tecnica più efficiente, in termini di costi, impiegando sostanze low cost, in termini di automatizzazione del processo, e dal punto di vista dei risultati ottenuti sulla conservazione del prodotto. Permette, infatti, di avere un effetto più duraturo nel tempo, non esaurendo la sua efficacia nei primi giorni di conservazione ma espletando le sue funzioni lungo tutto il periodo di shelf-life e facendo ipotizzare una minima estensione di quest’ultima. L’active packaging messo a punto utilizzando la tecnica del “layer-by-layer”, si è rivelato molto interessante sotto l’aspetto dell’efficacia antiossidante e antimicrobica e dal punto di vista della personalizzazione del dispositivo. Esso, infatti, si dimostra applicabile a numerose tipologie di alimento fresco, nonché ad alimenti con shelf-life più duratura, data la possibilità di ottenere un rilascio controllato nel tempo. La sua facilità di costruzione ne permette, inoltre, un facile scale-up di produzione.
Piva, G. (2017). CHARACTERIZATION AND DEVELOPMENT OF DIFFERENT METHODS TO EXTEND THE SHELF LIFE OF FRESH-CUT FRUIT.
CHARACTERIZATION AND DEVELOPMENT OF DIFFERENT METHODS TO EXTEND THE SHELF LIFE OF FRESH-CUT FRUIT
Piva, Giulio
2017-02-28
Abstract
Fresh-cut fruit is among the most highly perishable food product, characterized by short shelf-life (5-7 days), affected by microbiological spoilage and reactions caused by the presence of oxygen, such as enzymatic browning or oxidation reactions. The high added value of this product may justify the use of expensive storage solutions. Several methods exist to preserve ready-to-eat fruit, like dipping in natural or synthetic substances, or the use of active packaging and modified atmosphere packaging. These storage solutions affect differently on the final costs of the product but also on the preservation of the fruit, and on the maintenance of its quality during shelf-life. In the present doctoral period it was decided to address some factors that influence fresh-cut fruit quality during storage, particularly, enzymatic browning, the pomological decay and microbiological spoilage. To limit these factors it is chosen to use different solutions: the dipping in natural extracts, the active packaging based on natural antioxidants and antimicrobials compounds, as well as the development of a flexible high barrier film, by cellulose nanocrystals, for possible applications on fresh-cut fruit stored under modified atmosphere. The results we obtained on fresh-cut peach or pineapple, gave us many indications. The dipping into plant extract solutions allows a good maintenance of qualitative characteristics though lower than the active packaging. Furthermore, the use of the dipping technique exposes the product to water and air for excessive time, influencing the storage, when compared to the other used storage methods. Concerning the high barrier material developed we obtained very promising results, both for a longer shelf-life, and for a higher sustainability. The active packaging was the most efficient technique both in terms of costs, employing low cost substances, and in terms of automation of the process, as well as the quality preservation. Active packaging allows, in fact, to have longer lasting effect over the time, not exhausting its efficacy in the first days of storage but carrying out its role during all the shelf-life and assuming its minimum increase. In particular, we developed the technique of "layer-by-layer" that resulted very interesting in terms of antioxidant and antimicrobial effect, and a high device customization. In fact, this device can be applied to many types of fresh food, as well as on longer shelf-life food, giving the possibility to obtain a controlled release over the time. Indeed, it is suitable for an easy scale-up production.File | Dimensione | Formato | |
---|---|---|---|
Tesi di Dottorato Piva.pdf
Open Access dal 10/08/2018
Descrizione: Tesi Dottorato Piva
Dimensione
3.83 MB
Formato
Adobe PDF
|
3.83 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.