Konstantina Theodora Laina

Dr. Konstantina Theodora Laina

orcid

Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

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

Representative Publications

View All Publications
6 December 2024 in Molecules
Verified
Journal Article
Open access
PDF file
KLKonstantina Theodora Laina
Konstantina Theodora Laina
CDChristina G. Drosou
Christina G. Drosou
Chrysanthos StergiopoulosChrysanthos Stergiopoulos
Chrysanthos Stergiopoulos
PEPanagiota Eleni
Panagiota Eleni
Magdalini KrokidaMagdalini Krokida
Magdalini Krokida
This study presents the synergistic application of ultrasound- and microwave-assisted extraction (UAE–MAE) as a novel and efficient method for recovering bioactive compounds from the medicinal plants oregano, rosemary, Hypericum perforatum, and chamomile. Extraction parameters, including microwave (MW) power, ultrasound (US) power, and extraction time, were optimized using the response surface methodology (RSM), with ethanol as the solvent. Extracts were evaluated for total phenolic content (TPC) via the Folin–Ciocalteu method and antioxidant activity (IC50) using the DPPH assay. High-performance liquid chromatography with diode array detection (HPLC–DAD) identified the main bioactive compounds contributing to their antioxidant and therapeutic potential. The optimized UAE–MAE conditions enhanced phenolic recovery and antioxidant potential across all plants. Notably, Hypericum perforatum exhibited the highest TPC (53.7 mg GAE/g) and strongest antioxidant activity (IC50 29.8 mg extract/g) under 200 W MW, 450 W US, and 12 min, yielding 14.5%. Rosemary achieved the highest yield (23.36%) with a TPC of 26.35 mg GAE/g and an IC50 of 40.75 mg extract/g at 200 W MW, 700 W US, and 8 min. Oregano’s optimal conditions (500 W MW, 700 W US, 12 min) produced a TPC of 34.99 mg GAE/g and an IC50 of 50.31 mg extract/g. Chamomile extracts demonstrated lower phenolic content and antioxidant activity but achieved significant yields under 500 W MW, 700 W US, and 5 min. This study highlights UAE–MAE’s superior efficiency, showcasing its potential to maximize phenolic recovery sustainably, making it a promising technique for industrial and therapeutic applications.

20 April 2025 in Foods
Verified
Journal Article
Open access
PDF file
KLKonstantina Theodora Laina
Konstantina Theodora Laina
CDChristina G. Drosou
Christina G. Drosou
GFGeorgia Frakolaki
Georgia Frakolaki
Magdalini KrokidaMagdalini Krokida
Magdalini Krokida
The aim of this study was to develop a functional yogurt enriched with encapsulated probiotics with viable cell counts exceeding 107 CFU/g while preserving sensory quality, thereby enhancing health benefits and potentially preventing intestinal barrier dysfunction. Lacticaseibacillus rhamnosus LGG® was encapsulated in prebiotic-based matrices for enhanced stability, bioavailability, and controlled release under gastrointestinal conditions. Two encapsulation methods were investigated—the innovative electrohydrodynamic processing (electrospraying) method and conventional freeze drying. The encapsulation matrices were composed of inulin and whey protein isolate. Encapsulation efficiency was determined via microbiological analysis, and the encapsulated structures were characterized using scanning electron microscopy. The efficacy of the encapsulated probiotics was further assessed through exposure to gastrointestinal conditions. Electrosprayed LGG® provided the highest survival rates, up to 76%. Storage stability was evaluated at 4 °C for 105 days and after incorporation in commercial yogurt for 60 days. The sensory characteristics of the different yogurt products were also evaluated. The final products presented acceptable sensory features and final viable counts of 1.6–1.8 × 107 CFU/g. The denser structure of electrosprayed LGG® led to even higher protection. The findings highlight the potential of encapsulation—particularly electrospraying—in developing functional foods with improved probiotic delivery systems, paving the way for health-oriented dairy products.

2 April 2025 in Applied Sciences
Verified
Journal Article
Open access
CDChristina Drosou
Christina Drosou
KLKonstantina Theodora Laina
Konstantina Theodora Laina
MDMaria Dimoula
Maria Dimoula
PEPanagiota Eleni
Panagiota Eleni
CBChristos J Boukouvalas
Christos J Boukouvalas
MKMagdalini Krokida
Magdalini Krokida
This study investigates the valorization of tomato by-products—peels, seeds, and juice—through innovative extraction and bioprocessing techniques. Lycopene recovery from tomato peels was optimized using ultrasound- and microwave-assisted extraction (UAE-MAE) with ethyl lactate as the solvent. The optimal conditions (0.03 g/mL, 500 W microwave power, 600 W ultrasound power) yielded a lycopene content of 37.08 mg/100 g of peels and an extraction yield (EY) of 91.20%. For tomato seeds, oil extraction methods, including conventional stirring, UAE-MAE, Soxhlet extraction, and pressurized liquid extraction (PLE), were evaluated. Conventional stirring achieved the highest oil yield (19.66%), followed closely by UAE-MAE (19.53%). However, PLE produced the highest lycopene content (44.0 mg/100 g oil) and significant levels of linoleic acid (544.7 mg/g oil), though Soxhlet extraction yielded slightly more (608.9 mg/g oil). Tomato juice was processed into high-nutritional value vinegar via a two-stage fermentation process. The final product had 5.42% acidity, a pH of 2.85, and retained a high lycopene content (9.19 mg/100 g). This study underscores the potential of innovative extraction and bioprocessing strategies for the valorization of tomato by-products, promoting waste reduction and the development of high-value functional products in alignment with principles of the circular bioeconomy.

18 March 2025 in Agriculture
Verified
Journal Article
Open access
PDF file
CDChristina G. Drosou
Christina G. Drosou
KKKonstantina Kyriakopoulou
Konstantina Kyriakopoulou
KLKonstantina Theodora Laina
Konstantina Theodora Laina
ABAndreas Bimpilas
Andreas Bimpilas
Dimitrios TsimogiannisDimitrios Tsimogiannis
Dimitrios Tsimogiannis
Magdalini KrokidaMagdalini Krokida
Magdalini Krokida
This study investigates the recovery of bioactive polyphenolic compounds from the pomace of two white winemaking grape varieties, Moschofilero and Rhoditis. The pomace was subjected to two drying techniques: air drying (AD) and solar drying (SD). Extraction methods included microwave-assisted extraction (MW), ultrasound-assisted extraction (US), and Soxhlet extraction (S), using water and water–ethanol (WE) solvents. Antioxidant activity (IC50), total phenolic content (TPC), and total flavan-3-ol content (TFC) were determined. For Moschofilero, SD pomace extracted with US-WE showed the highest antioxidant activity (IC50: 0.59 mg/mL) and the highest phenolic recovery (TPC: 285.76 mg gallic acid equivalents (GAE)/g) and flavan-3-ol content (TFC: 46.21 mg catechin equivalents (CE)/g). For Rhoditis, AD pomace extracted with US-WE demonstrated superior antioxidant activity (IC50: 1.08 mg/mL), phenolic content (TPC: 216.51 mg GAE/g), and flavan-3-ol content (TFC: 35.96 mg CE/g). HPLC analysis identified quercetin-3-glucuronide, myricetin, and quercetin as the main flavonols in both grape varieties, with Moschofilero also containing isorhamnetin-3-glucoside and syringetin-3-glucoside. Drying and extraction methods significantly influenced the recovery of bioactive compounds, with US combined with AD or SD yielding the best results for both grape varieties These findings show that improved drying and extraction methods can add value to grape pomace for use in functional foods and nutraceuticals.

18 June 2025 in Coatings
Verified
Journal Article
Open access
PDF file
AMAlexandra Mari
Alexandra Mari
CDChristina G. Drosou
Christina G. Drosou
KLKonstantina Theodora Laina
Konstantina Theodora Laina
CVCristoforos Vasileiou
Cristoforos Vasileiou
Magdalini KrokidaMagdalini Krokida
Magdalini Krokida
Fresh-cut potatoes are highly perishable, requiring effective preservation strategies to maintain quality and extend shelf life. This study evaluated the use of edible coatings and the combination of osmotic dehydration and ohmic heating (OH-OD), both integrated with modified atmosphere packaging (MAP), to enhance microbial stability and reduce quality deterioration. Key quality parameters—including color stability, browning index, weight loss, microbial activity, and sensory attributes—were assessed. Results showed that coated samples (E-FP) had the lowest browning index (59.71) by day 8, compared to a value of 62.69 in control samples (C-FP). OH-OD-treated samples exhibited the least weight loss (6.73%) versus 17.75% in C-FP. Microbial analysis showed that E-FP samples maintained the lowest total viable count by day 8 (3.98 ± 0.02 log CFU/g), compared to OH-OD-FP (4.43 ± 0.13 log CFU/g) and C-FP (4.79 ± 0.06 log CFU/g), confirming the antimicrobial efficacy of the edible coating enriched with rosemary essential oil and ascorbic acid. Sensory evaluation further confirmed that coated samples retained superior sensory qualities, receiving the highest overall acceptance score of 8.86 ± 0.80, compared to values of 7.80 ± 0.98 for control samples (C-FP) and 2.80 ± 0.69 for OH-OD-FP samples, highlighting their enhanced consumer appeal. These findings highlight that combining advanced preservation techniques with MAP can significantly reduce moisture loss and microbial spoilage while maintaining freshness and sensory appeal. This integrated approach offers a promising solution for extending shelf life, reducing food waste, and supporting sustainability in response to consumer demand for minimally processed, high-quality fresh products.

23 September 2025 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CDChristina G. Drosou
Christina G. Drosou
IAIoanna Argyriou
Ioanna Argyriou
KLKonstantina Theodora Laina
Konstantina Theodora Laina
AMAlexandra Mari
Alexandra Mari
Magdalini KrokidaMagdalini Krokida
Magdalini Krokida
This study proposes a dual-approach strategy to formulate reduced-fat milk chocolate by combining cocoa butter (CB) substitution with emulsifier-based rheological optimization. CB was partially replaced at 20%, 30%, and 40% using whey protein isolate (WPI) and inulin (IN) blends (70:30, 50:50, 30:70 w/w). CB reduction increased plastic viscosity and yield stress, particularly in WPI-rich systems. The 50:50 WPI:IN ratio consistently minimized rheological drawbacks while maintaining melting, texture, and sensory quality. Caloric content was reduced by up to 9% (~50 kcal/100 g), most notably in IN-dominant samples. To overcome flow challenges at high substitution levels, emulsifiers—lecithin, ammonium phosphatide (AMP), and polyglycerol polyricinoleate (PGPR)—were assessed. AMP (≤0.5% w/w) and PGPR (0.15–0.3% w/w) effectively reduced viscosity and yield stress; lecithin showed limited effect above 0.6%. The optimized system (0.5% AMP + 0.15% PGPR) applied to 40% CB-reduced chocolate with 50:50 WPI:IN restored desirable rheology (3.42 Pa·s viscosity; 7.91 Pa yield stress) and improved mouthfeel and acceptability. This integrated formulation enables significant fat and calorie reduction without compromising product quality, supporting the development of healthier chocolate products.