Theofilos Frangopoulos

Dr. Theofilos Frangopoulos

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Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 July 2023 in Foods
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TFTheofilos Frangopoulos
Theofilos Frangopoulos
AMANNA MARINOPOULOU
ANNA MARINOPOULOU
AGAthanasios Goulas
Athanasios Goulas
ELEleni Likotrafiti
Eleni Likotrafiti
JRJonathan Rhoades
Jonathan Rhoades
VKVassilis Karageorgiou
Vassilis Karageorgiou
A definitive screening design was used in order to evaluate the effects of starch, glycerol and montmorillonite (MMT) concentrations, as well as the drying temperature, drying tray type and starch species, on packaging film’s functional properties. Optimization showed that in order to obtain films with the minimum possible thickness, the maximum elongation at break, the maximum tensile strength, as well as reduced water vapor permeability and low opacity, a combination of factors should be used as follows: 5.5% wt starch concentration, 30% wt glycerol concentration on a dry starch basis, 10.5% wt MMT concentration on a dry starch basis, 45 °C drying temperature, chickpea as the starch species and plexiglass as the drying tray type. Based on these results, starch films were prepared, and fresh minced meat was stored in them for 3 days. It was shown that the incorporation of MMT at 10.5% wt on a dry starch basis in the packaging films led to a decreased mesophilic and psychrotrophic bacteria growth factor compared to commercial packaging. When assessed for their biodegradability, the starch films disintegrated after 10 days of thermophilic incubation under simulated composting conditions. Finally, to prove their handling capability during industrial production, the starch films were rewound in a paper cylinder using an industrial-scale rewinding machine.


25 August 2023 in Polymers
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KNKonstantinos Noulis
Konstantinos Noulis
TFTheofilos Frangopoulos
Theofilos Frangopoulos
AAAthanasia Arampatzidou
Athanasia Arampatzidou
LTLazaros Tsekmes
Lazaros Tsekmes
AMANNA MARINOPOULOU
ANNA MARINOPOULOU
VKVassilis Karageorgiou
Vassilis Karageorgiou
Synthetic polymers are the main food packaging material, although they are nonbiodegradable and their recycling process is expensive. A biodegradable, eco-friendly material, with high availability and low cost, such as starch, is a promising solution for the production of films for food packaging. To enhance starch film mechanical and barrier properties, nanoclays have been incorporated within the film matrix. Crosslinking is a well-established method to modify starch properties, but it has not been investigated in combination with nanoclay addition. In the present study, films were developed with starch that was crosslinked through the addition of 5, 15, and 40% wt. sodium trimetaphosphate (STMP) based on dry starch weight. To investigate the interaction between crosslinking and nanoclay addition, montmorillonite (MMT) was added at a 10.5% wt. concentration based on dry starch weight. Experimental data revealed a synergistic effect between STMP crosslinking and MMT addition regarding film thickness, elongation at break, color properties, and opacity. Regarding barrier properties, MMT addition negated the effect of STMP crosslinking, while, in the case of moisture content, it did not alter the effect of STMP crosslinking. Finally, in the case of tensile strength, a synergistic effect followed by a negative interaction was observed. In conclusion, the addition of MMT can potentially enhance, alongside crosslinking, some properties of the films, while other properties are not affected any more than just by crosslinking.

24 November 2024 in Applied Sciences
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TFTheofilos Frangopoulos
Theofilos Frangopoulos
AKAntonios Koliouskas
Antonios Koliouskas
DPDimitrios Petridis
Dimitrios Petridis
The accelerated life testing (ASLT) method was used to evaluate the effect of increasing the storage temperature from 10 to 40 °C on the aerobic plate count (APC), the pH, and the colorimetric parameters (L*, a*, b*) of pasteurized orange juice during 40 days of storage. For APC growth, a polynomial model was found to fit better, and at the lower temperatures of 10 and 15 °C, the shelf life was longer, as expected. More specifically, 15 and 10 days were needed, respectively, until the rise in the APC population to 1000 cfu/mL. However, for the temperature range of 30–40 °C, only approximately 3 days were needed to reach 1000 cfu/mL APC. Regarding pH, according to an exponential 3P model, a stable trend was apparent at all temperatures until 30 days of storage, followed by a more abrupt decreasing trend at 25 °C. The lightness (L*), redness (a*), and yellowness (b*) of the juice showed a decreasing trend with the temperature increase, and this trend was more profound at higher temperature levels. The multiple regression analysis between the predictors L*, a*, b*, pH, storage temperature, and the APC response showed an increase in APC growth when the colorimetric parameters decreased and the temperature increased.


22 May 2025 in Applied Sciences
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TFTheofilos Frangopoulos
Theofilos Frangopoulos
DPDimitrios Petridis
Dimitrios Petridis
DEDidaskalou Eirini
Didaskalou Eirini
TETzika Eleni
Tzika Eleni
Applying a statistical mixture design, 10 different blending combinations of traditional Greek sausages were prepared based on different percentages of the three ingredients (buffalo meat: 40–70%; pork fat: 0–30%; buffalo fat: 0–30%). Samples were then analyzed for chemical composition, instrumental textural properties and sensory attributes, using a balanced incomplete block design (BIBD) for the sensory analysis. According to the chemical set, the fat content increased when both fat origins increased, and the protein content also increased when the proportion of buffalo meat increased in the formulations. Regarding textural properties, an instrumental analysis revealed a positive relationship between fat level increases and hardness, whereas a sensory analysis revealed a rise in hardness when the proportion of buffalo fat increased, but that was not observed for sensory juiciness. A hierarchical cluster analysis and PCA revealed a strong relationship between the elasticity, juiciness and overall acceptability of samples with high fat contents, regardless of the origin of the fat, whereas at the same time, a strong relationship was found between high buffalo meat contents (70%) in samples and both instrumental and sensory hardness, chewiness and protein content.