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Vitamin C, a water-soluble compound, is a natural antioxidant in many plant-based products, possessing important nutritional benefits for human health. During fruit and vegetable processing, this bioactive compound is prone to various modes of degradation, with temperature and oxygen being recognised as the main factors responsible for this nutritional loss. Consequently, Vitamin C is frequently used as an index of the overall quality deterioration of such products during processing and post-processing storage and handling. Traditional preservation methods, such as thermal processing, drying and freezing, are often linked to a substantial Vitamin C loss. As an alternative, novel techniques or a combination of various preservation steps (“hurdles”) have been extensively investigated in the recent literature aiming at maximising Vitamin C retention throughout the whole product lifecycle, from farm to fork. In such an integrated approach, it is important to separately study the effect of each preservation step and mathematically describe the impact of the prevailing factors on Vitamin C stability, so as to be able to optimise the processing/storage phase. In this context, alternative mathematical approaches have been applied, including more sophisticated ones that incorporate parameter uncertainties, with the ultimate goal of providing more realistic predictions.

Fish oil, a rich source of omega-3 polyunsaturated fatty acids (PUFA), is a vital nutritional component, but considering its susceptibility to oxidation, it could benefit from an effective encapsulation system. This study aims to optimize high-pressure homogenization (HPH) parameters (pressure, number of passes) and wall material composition to maximize the encapsulation efficiency (EE) of fish oil, using different concentrations of maltodextrin with Arabic gum or sodium alginate. Key metrics such as emulsion droplet size, encapsulation efficiency, color, and oxidation in the final freeze-dried product were evaluated. Optimal values were achieved at 60 MPa, resulting in the lowest mean droplet diameter (369.4 ± 3.8 nm) and narrow distribution (0.197 ± 0.011) of the fish oil micelles prepared with a mixture of Tween80 and sodium caseinate as an emulsifier, without significant oxidation after four cycles of homogenization, while 80 MPa led to the highest EE (up to 95.6%), but increased oxidation. The combination of 10% w/w Arabic gum or 1% w/w sodium alginate with 20% w/w maltodextrin achieved the highest EE (79.1–82.9%) and whiteness index (82.5–83.0), indicating neutral-colored well-encapsulated fish oil without oxidation, which is desirable for product stability. Selecting optimal HPH conditions and wall material is crucial for the encapsulation efficiency and oxidation stability of omega-3 PUFA delivered in dehydrated forms.

This study focuses on the design, development and quality assessment of an innovative shelf-stable olive paste dip, aiming at the valorization of by-products of tomato processing and olive oil production (Product 1: OPD). Bioactive compounds (BACs), i.e., total carotenoids and phenolic components, were extracted from tomato and olive pomace, respectively. For further enrichment, BACs were incorporated in olive paste dips into a second product (OPDEnr) in encapsulated form (Product 2: OPDEnr). The total carotenoids (TC) of OPD and OPDEnr were 20.0 ± 2.0 and 30.2 ± 1.0 mg/kg, respectively. Similarly, the total phenolic content (TPC) and the antioxidant activity (AA) were 1.62 ± 0.08 and 3.05 ± 0.10 mg GAE/g, and 0.801 ± 0.075 and 0.976 ± 0.032 mg Trolox/g, respectively. The quality of the developed olive paste dip product prototypes was assessed using the Accelerated Shelf Life Testing (ASLT) methodology at a temperature range of 20–40 °C. Both OPDEnr and OPD were microbiologically stable during storage (i.e., not exceeding 4 logCFU/g for total mesophilic counts), and no lipid oxidation evolution was observed (Peroxide Value, PV did not exceed 4 meq O2/kg), while TC, TPC and AA values remained stable. The shelf life of OPDEnr and OPD was determined based on the overall sensory quality and was found to be 120 and 211 d at 25 °C, respectively. OPDEnr and OPD were characterized by a high quality (color and texture), with an overall sensory score of 8.0/9.0 and 9.0/9.0, respectively, in the acceptability–hedonic scale 1 (dislike extremely)-9 (like extremely), and they could potentially be consumed as an antioxidant-enriched olive paste dip.

Olive oil production is characterized by large amounts of waste, and yet is considerably highly valued. Olive pomace can serve as a cheap source of bioactive compounds (BACs) with important antioxidant activity. Novel technologies like Pulsed Electric Fields (PEF) and High Pressure (HP) and microwave (MW) processing are considered green alternatives for the recovery of BACs. Different microwave (150–600 W), PEF (1–5 kV/cm field strength, 100–1500 pulses/15 µs width), and HP (250–650 MPa) conditions, in various product/solvent ratios, methanol concentrations, extraction temperatures, and processing times were investigated. Results indicated that the optimal MW extraction conditions were 300 W at 50 °C for 5 min using 60% v/v methanol with a product/solvent ratio of 1:10 g/mL. Similarly, the mix of 40% v/v methanol with olive pomace, treated at 650 MPa for the time needed for pressure build-up (1 min) were considered as optimal extraction conditions in the case of HP, while for PEF the optimal conditions were 60% v/v methanol with a product/solvent ratio of 1:10 g/mL, treated at 5000 pulses, followed by 1 h extraction under stirring conditions. Therefore, these alternative extraction technologies could assist the conventional practice in minimizing waste production and simultaneously align with the requirements of the circular bioeconomy concept.

Spent Coffee Ground (SCG) is the main coffee industry by-product, rich in dietary fibers and polyphenols. The extractable material of SCG was fractionated, and the phenolic compounds were identified and quantified. Chlorogenic and neochlorogenic acids were identified as the main phenolic components, and the Total Phenolic Content (TPC) of SCG was determined to be 2.16% (dry SCG basis). Furthermore, SCG was characterized in terms of Total Dietary Fiber content, which amounted to 66%. The SCG was valorized for the development of a bakery product (cookie) enhanced with fiber and bioactive polyphenols. Cookies were produced with the addition of 4% and 7% dry and defatted SCG (baked cookie basis). The produced cookie prototypes presented TPC and dietary fiber dependent on the addition level of SCG. TPC values were determined at 588 and 1017 ppm, while dietary fiber values were at 2.7 and 4.6%, respectively. The shelf life of the cookies was monitored over 143 days at three different temperatures (25 °C, 35 °C, and 45 °C) in terms of texture (hardness), color, Peroxide Value (PV), and TPC. It was observed that the PV value significantly increased in samples with incorporated SCG, stored at 45 °C, while in those stored at 25 °C and 35 °C, PV remained at low levels. The TPC of the SCG-enriched samples remained practically constant during the shelf life analysis, while color and hardness increased (mathematically modeled). SCG-added cookies were characterized by increased darkness, increased hardness, and a mild (desirable) coffee flavor. The overall sensory impression scores for 0%, 4%, and 7% SCG-added cookies were 7.5, 8.0, and 8.2, respectively. Based on sensory evaluation test results, the shelf lives of 0%, 4%, and 7% SCG at 25 °C were 359, 435, and 471 days, respectively. Overall, SCG is a potentially valuable ingredient that can be used to develop innovative food (baked) products with enhanced nutritional value and increased shelf life.

Vacuum packed Bratwurst type cooked sausages and sliced or cubed meat products that have limited shelf-life of few days in chilled storage were HP processed (5 min, 600 MPa, 25 °C) and stored at different temperatures (0–15 °C). Color, texture, and microbiological and sensory evaluation were kinetically studied for control and HP treated samples. HP treatment did not alter the color and texture of the treated samples when compared to untreated ones. Lactic acid bacteria were found to be the main spoilage index. The rates of microbiological and organoleptic deterioration were estimated, and their temperature dependence was modeled by the Arrhenius equation. An increase of their shelf life of five to eight times was estimated, compared to untreated ones. A sensory survey on HP treated cooked ham showed that the consumers could not distinguish differences between control and processed samples immediately after processing. Obtained results were used along with appropriate tools relevant to cold chain management to demonstrate that HP treated products are less perishable compared to control ones, allowing for short exposure to temperature deviations during transportation and storage. This has a positive impact on the reduction of the frequency of spoiled products before consumption, acting as a useful tool for the meat product’s loss and waste reduction.

The objective of this work was to evaluate the potential of PEF application on the decrease in orange peel air-drying time and temperature, resulting in energy savings. Orange peel waste (by-product of squeezable orange juice typical production, with a moisture content of 70%) was PEF pretreated (1.0–5.0 kV/cm electric field strength, frequency of 20 Hz, pulse width 15 μs, >1000 pulses), achieving a cell disintegration index Z ranging from 0.1 to 0.8. Drying experiments of PEF-treated orange peels were carried out at mild temperatures (40–70 °C). The moisture diffusion coefficients Deff and the air-drying energy consumed of all samples were estimated and compared. At low drying temperatures (<55 °C), PEF treatment led to increased effective moisture diffusivity Deff by up to 25%, resulting in reduced drying time and energy savings up to 15 MJ/kg, compared to untreated samples. More intense PEF conditions resulted in higher drying rates, while, for temperatures > 60 °C, there was no significant effect on the moisture diffusion coefficient for PEF pretreated samples. PEF treatment did not lead to changes in the antioxidant activity of dried samples. The results showed the potential of PEF pretreatment to accelerate the drying process of orange peel waste minimizing energy consumption.

This study explores the osmotic dehydration (OD) of fresh-cut cherry tomatoes through the application of Pulsed Electric Fields (PEF) and High-Pressure (HP) pre-treatments. Untreated, PEF-treated (1.8 kV/cm, 0–300 pulses), and HP-treated (0–600 MPa, 5 min) tomatoes were subjected to osmotic dehydration at 35 °C for up to 3 h. The results reveal that a 100-pulse PEF treatment and HP treatment at 600 MPa yielded optimal outcomes in terms of both OD enhancement (with effective moisture diffusion coefficients of 7.91 · 10−10 m2/s for PEF and 7.40 · 10−10 m2/s for HP-treated tomatoes compared to 5.17 · 10−10 m2/s for untreated samples) and product acceptability (achieving overall acceptance scores between 7 and 8). Applying PEF (100 pulses) and HP (600 MPa) pre-treatments reduced the water activity (aw) to 0.887 and 0.760, respectively, after 3 h of OD, compared to aw = 0.923 for untreated OD samples. The selection of these pre-treatment conditions enabled effective dehydration and quality retention, extending the shelf life by up to 40 days under chilled storage.

The objective of this study was to obtain and evaluate a coffee aroma extract/oil with sensorial attributes close to the original brew of Greek coffee for use in an instant Greek coffee powder. The oil was obtained directly from commercial Greek coffee by solid-liquid extraction using hexane as a solvent and treated with a series of hexane-ethanol mixtures (0:10, 1:4, 1:9) to remove the intense roasted flavor of the crude coffee oil obtained by hexane; the de-oiled coffee was used for the recovery of water-soluble compounds, and the produced water extract was freeze-dried. The aromatic volatiles of the coffee oil samples were analyzed by using a purge-and-trap device coupled to GC-MS, as well as sensory analysis. The instant Greek coffee powder was produced by mixing the freeze-dried base (74.4%) with the extract derived after treatment of the crude oil with hexane-ethanol mixture 1:4 (18.2%) and foaming agent (7.4%). Two different materials were studied as bases: instant coffee (F3Gr-D) and ground Greek coffee (reference sample, CGr). The shelf-life stability of the produced powders was examined at three storage temperatures (25, 45, 60 °C). Instrumental analysis (purge-and-trap GC-MS) of aroma and sensory analysis (aroma, taste, staling, total sensory quality on a 1–9 hedonic scale) was conducted. Aroma loss (furfuryl alcohol, furfural, dimethyl pyrazines, ethyl methyl pyrazines) and scores for sensory attributes during storage were modeled using 1st and 0-order reaction kinetics, respectively. The storage temperature effect was expressed by the Arrhenius model (activation energy Ea). According to the results, the developed instant coffee powder presented satisfactorily the aroma characteristics of regular Greek coffee. The shelf life for the instant Greek coffee powder was estimated as 80 days (air packed) (based on 20% retention of furfuryl alcohol that was the most abundant aromatic volatile of Greek coffee aroma, ground as well as extract oil).

This study investigates the extraction kinetics of luteolin, a bioactive flavonoid with recognized antioxidant and health-promoting properties, from the aerial parts of Reseda luteola (dyer’s weld), with emphasis on its industrial potential. A comparative analysis with peanut shells (Arachis hypogea) identified R. luteola as a superior source, containing 14 ± 3 mg of LUT/g of material, approximately eight times higher than the amount in peanut shells. Luteolin occurred predominantly as luteolin-7-O-glycoside (57%) and the aglycone (35%). Methanolic semi-batch extraction at 25 °C yielded 9.6 mg LUT/g (70%) within 60 min at a solid-to-liquid ratio of 1:9, demonstrating significantly greater solvent efficiency than conventional Soxhlet or maceration techniques. Kinetic modeling, based on Fick’s second law, revealed a biphasic process with a low rate constant ratio (3:1) between the two stages, indicating the need for process optimization. These results establish R. luteola as a cost-effective and sustainable source of luteolin for dietary supplements and functional foods, while indicating the need to explore alternative solvents and advanced extraction methods to further optimize yield and efficiency.