Comparative analysis of aroma and phenolic compounds
in strawberry nectar subjected to equivalent thermal,
ohmic heating, high pressure, and pulsed electric fields
processes at pilot scale

Dario Pavón-Vargas, Krystina Simkova, Alema Puzović, Andres Moreno-Barreto, Astrid Gědas, Helen Murray, Ibrahim Rabeeah, Sebastian Rincon, Ngoc Quynh Anh Truong, Alberto Zavarise, et al.

► To cite this version:

Dario Pavón-Vargas, Krystina Simkova, Alema Puzović, Andres Moreno-Barreto, Astrid Gědas, et al. Comparative analysis of aroma and phenolic compounds in strawberry nectar subjected to equivalent thermal, ohmic heating, high pressure, and pulsed electric fields processes at pilot scale. LWT - Food Science and Technology, 2025, 228, 10.1016/j.lwt.2025.118066. hal-05135600

HAL Id: hal-05135600

https://hal.inrae.fr/hal-05135600v1

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Comparative analysis of aroma and phenolic compounds in strawberry nectar subjected to equivalent thermal, ohmic heating, high pressure, and pulsed electric fields processes at pilot scale

Dario Pavón-Vargas<sup>a</sup>, Krystina Simkova<sup>b</sup>, Alema Puzović<sup>b</sup>, Andres Moreno-Barreto<sup>c</sup>, Astrid Gědas<sup>d</sup>, Helen Murray<sup>e</sup>, Ibrahim Rabeeah<sup>f</sup>, Sebastian Rincon<sup>g</sup>, Ngoc Quynh Anh Truong<sup>h</sup>, Alberto Zavarise<sup>f</sup>, Hassan Zia<sup>b,j</sup>, Luca Sandei<sup>c</sup>, Massimiliano Rinaldi<sup>h</sup>, Stephane Georgé<sup>j</sup>, Mario Gozzi<sup>k</sup>, Manfred Gössinger<sup>e</sup>, Severin Guski<sup>l</sup>, Stefan Humel<sup>l</sup>, Jerneja Jakopic<sup>c</sup>, Carine Le Bourvellec<sup>h</sup>, Sara Rainieri<sup>a</sup>, Maja Mikulic-Petkovsek<sup>b</sup>, Agnes Weiss<sup>d</sup>, Marc Schmidt<sup>m</sup>, Francesco Guareschi<sup>n</sup>, Christian Molitor<sup>f</sup>, Mikko Hofsommer<sup>i</sup>, Ana Slatnar<sup>b</sup>, Heidi Halbwirth<sup>f</sup>, Luca Cattani<sup>o,p,*</sup>

ARTICLE INFO

Keywords:

Strawberry nectar

Aroma compounds

Phenolic compounds

High pressure processing

Pulsed electric fields

Ohmic heating

ABSTRACT

This study investigates the effects of four preservation treatments: thermal pasteurization (TP), ohmic heating (OH), high-pressure processing (HPP), and pulsed electric fields (PEF), on the aroma and phenolic compounds of strawberry nectar, under equivalent microbial inactivation conditions (5-log reduction) on pilot-scale systems. Changes during 60 days of storage at 4 °C were also evaluated. HPP was the most effective method for retaining aroma compounds, with initial levels of 5.29 ± 0.03 mg/L, closely to the untreated samples, while TP showed the lowest retention (2.94 ± 0.13 mg/L). During storage, HPP-treated samples had a 41.6 % reduction in aroma compounds but still the highest remaining concentrations after storage compared to the other treatments. Key aroma markers, such as mesifurane, methyl and ethyl butyrate, were significantly better preserved in HPP and PEF treated samples compared to TP and OH. Phenolic content followed a similar trend: immediately after treatment HPP and PEF samples exhibited the highest total phenolic content (TPC), including anthocyanins like pelargonidin-3-glucoside, which constituted up to 81 % of total anthocyanins. Non-thermal methods (HPP and PEF) preserved phenolics better than TP, although differences between treatments were not significant after 60 days of storage. OH demonstrated intermediate performance due to its uniform heating process that minimized

<footnote><sup>a</sup> Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze 181/A, I-43124, Parma, Italy</footnote>

<footnote><sup>b</sup> Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia</footnote>

<footnote><sup>c</sup> Experimental Station for the Food Preservation Industry-SSICA, Via Faustino Tanara, 31, 43100, Parma, Italy</footnote>

<footnote><sup>d</sup> Food Microbiology, Hamburg School of Food Science, University of Hamburg, Ohnhorststrasse 18, 22609, Hamburg, Germany</footnote>

<footnote><sup>e</sup> Department of Fruit Processing, Federal College and Institute for Viticulture and Pomology, A-3400, Klosterneuburg, Austria</footnote>

<footnote><sup>f</sup> Institute of Chemical, Environmental & Bioscience Engineering, Technische Universität Wien, Vienna, 1060, Austria</footnote>

<footnote><sup>g</sup> INRAE, Avignon University, UMR408 SQPOV, F-84000, Avignon, France</footnote>

<footnote><sup>h</sup> Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124, Parma, Italy</footnote>

<footnote><sup>i</sup> GfL Gesellschaft für Lebensmittel-Forschung mbH, Landgrafenstrasse 16, 10787, Berlin, Germany</footnote>

<footnote><sup>j</sup> Centre Technique de Conservation des Produits Agricole, 449 Clément Ader, 84000, Avignon, France</footnote>

<footnote><sup>k</sup> CFT S.P.A, Via Paradigna, 94/a, 43122, Parma, Italy</footnote>

<footnote><sup>l</sup> Austria Juice GmbH, Kröllendorf 45, 3365, Allhartsberg, Austria</footnote>

<footnote><sup>m</sup> Elea Technology GmbH, Prof. von Klitzing Str. 9, 49610, Quakenbrueck, Germany</footnote>

<footnote><sup>n</sup> HPP Italia srl, Via Carbognani, 6 43029 Traversetolo, Parma, Italy</footnote>

<footnote><sup>o</sup> Department of Engineering for Industrial Systems and Technologies, University of Parma, Parco Area delle Scienze 181/A, I-43124, Parma, Italy</footnote>

<footnote><sup>p</sup> SITEIA.PARMA Interdepartmental Centre, University of Parma, Parco Area delle Scienze, 43124 Parma, Italy</footnote>

<footnote>* Corresponding author. Department of Engineering for Industrial Systems and Technologies, University of Parma, Parco Area delle Scienze 181/A, I-43124 Parma, Italy.</footnote>

<footnote>E-mail address: luca.cattani1@unipr.it (L. Cattani).</footnote>
thermal degradation. Overall, non-thermal methods emerged as the most effective for preserving both aroma and phenolic profiles, followed by OH, while TP resulted in the greatest losses. These findings highlight the potential of non-thermal and alternative thermal technologies over thermal pasteurization to maintain the sensory and nutritional quality of fruit-based beverages.

# 1. Introduction

In recent years, there has been a growing demand for beverages that provide not only appealing taste but also nutritional and functional benefits. Consumers nowadays favour health-focused products and preservation technologies that retain the sensory and nutritional quality (Zhang et al., 2019). The sensorial aspects, such as aroma and phenolic compounds are of particular interest. These compounds are essential for both the flavour and health benefits of juices and nectars (Putnik et al., 2020; Santos et al., 2018). Strawberry nectar is well known for its high level of phenolic compounds, which have health benefits, along with its rich aromatic profile that contributes to its sensory appeal (Rapuru et al., 2022). However, these compounds are susceptible to degradation during conventional treatments, such as thermal pasteurization. The main challenge is therefore to preserve the sensory and nutritional characteristics while ensuring safety and extended shelf-life. As a result, research has focused on exploring alternative thermal and non-thermal processing technologies, such as ohmic heating (OH), high pressure processing (HPP), and pulsed electric fields (PEF). These three technologies have been proven to inactivate microorganisms effectively while maintaining the quality of juices (Chacha et al., 2021; Tiwari et al., 2009). Considering the importance of aroma and phenolic compounds for consumers, it is crucial to understand how these compounds are affected by the different preservation technologies.

Thermal pasteurization in strawberry juices has been extensively studied and widely used. Nevertheless, its negative impact on phenolic and aroma compounds has been well documented (Stübler et al., 2020). For instance, a study by Razola-Díaz et al. (2024) found that thermal treatment on strawberry smoothie led to extensive losses of phenolic compounds and antioxidant capacity. In contrast, several researchers have indicated that HPP treatment can effectively retain the colour, flavour, and antioxidants of strawberry juice, while extending the shelf life of the product without the need for high temperatures (Cao et al., 2012; Xing et al., 2023). Furthermore, PEF treatment has gained attention for its ability to inactivate microorganisms in fruit juices, while also preserving the sensorial and nutritional quality (Koubaa et al., 2018). In contrast, OH has not been extensively studied for its impact on strawberry nectar but has demonstrated promising results in preserving the quality of other fruit juices (Li et al., 2021; Misra & Kumar, 2020). By using electrical currents to rapidly and uniformly heat the product, OH minimises quality loss and reduces the degradation of thermolabile molecules like phenolics and aromatic compounds (Astráin-Redín et al., 2024).

Despite the advances in fruit juice preservation research, few studies have conducted a comparative analysis of more than two different technologies, and even fewer studies have been conducted at pilot scale units, focusing specifically on achieving equivalent microbial inactivation, such as a 5-log reduction of a specific pathogen. This study addresses these gaps with three key strengths: (1) the use of pilot-scale systems (up to 400 L/h), ensuring industrial relevance and scalability; (2) a comparative analysis of four technologies (OH, TP, HPP, PEF) under standardized microbial inactivation conditions; and (3) coordinated processing across international partners to ensure consistent raw material quality, nectar formulation, and microbial loads. The lack of equivalent comparative research is particularly detrimental to the evaluation of thermal treatments like OH and TP compared to HPP, and PEF. These gaps highlight the need for studies that assess the impacts of these preservation methods under equivalent conditions. The present study was carried out to fill this gap with a comparative analysis of the

changes in the aromatic and phenolic compounds on strawberry nectar, subjected to equivalent thermal and non-thermal treatments. While this study demonstrates strong industrial relevance, it is important to note that the pilot-scale trials required a substantial quantity of raw material, which may pose challenges for replication in resource-limited settings. Nevertheless, this scale was essential to ensure realistic and applicable results. Although the evaluation did not include detailed comparisons of energy consumption, operational costs, or equipment availability across technologies, the current findings provide a solid foundation for future work that could address these important practical dimensions.

The raw material, nectar formulation, and processing conditions were carefully coordinated between the different partners to ensure similar initial microbial load and equivalent microbial inactivation for all the pilot scale plants. Four parties were involved in the processing: thermal treatment was carried out by CFT SpA (Parma, Italy), OH by CTCPA (Avignon, France), HPP by HPP Italia (Traversetolo, Italy), and PEF by ELEA (Quakenbrück, Germany).

# 2. Materials and methods

## 2.1. Materials

A total of 972 kg of strawberry puree, consisting of a mixture of Spanish varieties, was purchased from SVZ International BN (Breda, The Netherlands). The puree was processed through a 0.6 mm mesh, sorted into 18 kg cardboard boxes, and frozen at -20 °C without any further processing. It was then transported in frozen condition (-20 °C) to the different sites for the treatments. For the formulation of the nectar, the strawberry puree was thawed at room temperature. Sucrose and food-grade citric acid, both purchased from local markets, were added along with filtered tap water. The final formulation consisted of 40 % puree, sufficient sucrose to achieve a Brix value of 12, and enough citric acid to reach an acidity of 5.0 g/kg. The resulting nectar had a pH value between 3.1 and 3.4. The nectar was then subjected to 4 different treatments: TP, OH, PEF, and HPP, additionally untreated (UT) samples were collected as a control.

## 2.2. Process conditions and microbial validations

The processing conditions were selected to ensure an equivalent process value that achieves a 5-log reduction, as recommended by the FDA for fruit juices and nectars (Food and Drug Administration, 2001). This standard is based on targeting the most heat-resistant pathogen, and for strawberry nectar, *Escherichia coli* strain ATCC 8739 serves as an appropriate surrogate for thermal inactivation, because it exhibits heat resistance similar to that of the target pathogen (Gędas et al., 2024).

TP and OH processing conditions were established based on the thermal resistance parameters of the reference microorganism, as determined previously in laboratory conditions (Gędas et al., 2024). These parameters were then validated on a pilot scale to achieve a 5-log reduction in microbial population. Since the reduction kinetics were consistent between OH and TP (Salari & Jafari, 2020), the same treatment was applied to both processes. Additionally, the use of industrial electrodes with a 25 kHz frequency in the OH process helped minimize the effects of electrolysis, ensuring only thermal effects (Lima et al., 1999). In this study, a mild pasteurization treatment at 72 °C for 117 s was used.

In a previous study on strawberry nectar, pressures of 600 MPa for 3 min were tested, achieving microbial safety but failing to inactivate
enzymes like pectin methyl esterase (PME), which affected viscosity and texture over time (Lacey et al., 2023). To address this, the holding time was extended to 5 min, ensuring both microbial safety and enzyme inactivation. A preliminary trial under these conditions (600 MPa and 5 min) showed a 5-log reduction in the selected surrogate.

Microbial validation tests for PEF treatment of strawberry nectar, inoculated with *E. coli* ATCC 8739, were conducted at specific energy levels of 80, 90, and 100 kJ/L. The maximum outlet temperature reached was 65.3 °C, with a temperature increase of 26 °C. After processing, samples were cooled and stored at +4 °C for microbial analysis. The selected PEF parameters, based on achieving a 5-log microbial reduction of the surrogate, were 20 kV/cm, 100 kJ/L, 7 µs pulse width, and 109 µs treatment time.

## 2.3. Thermal pasteurization (TP) setup

The TP was carried out at CFT SpA (Parma, Italy) using an indirect heating system provided by a shell and tube heat exchanger (UHT-MIX pilot line, CFT SpA, Parma, Italy). The heat exchanger consisted of four tube bundles; each made of eight AISI316L pipes with an internal diameter of 16.5 mm and a length of 6 m. The velocity at the fastest point in the system was used to calculate the residence time required for the product to reach the target temperature. A total of 400 L of nectar were used for this assay. After the thermal treatment, the samples were cooled down to 20 °C and collected in an aseptic tank, before being transferred to sterile sampling bags (Keofitt®, Svendborg, Denmark) for storage at -20 °C.

## 2.4. Ohmic heating (OH) setup

The OH treatment was carried out at the Centre Technique de la Conservation des Produits Agricoles (CTCPA) in Avignon, France, using a 60-kW continuous OH system (CFT SpA, Parma, Italy). The system operates with 1–5 kV at a frequency of 25 kHz. A total of 400 L of strawberry nectar, preheated to 20 °C, was pumped into the system. After processing, the nectar was cooled down and aseptically filled into metallized Fres-co® aseptic system bags (Goglio SpA, Milan, Italy) using the Macropack F1 aseptic filler (CFT SpA, Parma, Italy). The filled bags were then frozen at -20 °C.

## 2.5. High pressure processing (HPP) setup

HPP treatments were performed utilising an Avure Technologies QFP-350L 600 high pressure processing system (Avure Technologies Inc., Erlanger, Kentucky, USA) located at HPP ITALIA s.r.l in Traversetolo, Italy. Cold water at 4 °C was used as the pressure transfer medium. The temperature of the medium increased by only 3 °C per 100 MPa during the compression process. The required pressure of 600 MPa was reached in around 100 s, and the pressure release occurred immediately after the treatment time. Before treatment, the nectar was filled up into 250 mL PET plastic bottles. After treatment, the samples were stored at -20 °C.

## 2.6. Pulsed electric fields (PEF) setup

PEF assays were performed at Elea Technology GmbH in Quakenbrück, Germany. The strawberry nectar was treated in a PEF unit pilot plant (PEFPilot™ Dual, Elea Technology GmbH, Quakenbrück, Germany) equipped with two co-linear DN10 PEF treatment chambers, operating in continuous mode. During processing, the inlet temperature of the strawberry nectar was maintained at +40 °C using a coil heat exchanger. At this temperature, the nectar conductivity was measured to be 1.9 mS/cm. The PEF processing parameters were set as follows: bipolar square wave pulse shape, fixed pulse width of 7 µs, and an electrode gap of 10 mm. The average flow rate during the treatment was 68 L/h. The pulse peak voltage was adjusted to achieve an electric field

strength of 20.0 kV/cm, and a specific energy of 100 kJ/L. Immediately after treatment, the samples were filled into sterile PET containers and stored at -20 °C before distribution for further analysis.

## 2.7. Storage distribution and sampling

Immediately after processing, all samples were frozen at -20 °C to preserve their quality for further analysis, with untreated samples taken as controls. The frozen samples were carefully packed and transported under frozen conditions to their respective destinations for the analysis of aroma compounds and polyphenols. Vitamins and colour were also analysed and published previously (Zia et al., 2025). All samples from the four treatments were delivered together. Upon arrival, the samples were defrosted, and measurements of aroma compounds and polyphenols were conducted simultaneously across all treatments. For the shelf-life study, the thawed samples were stored at +4 °C and analysed at 30- and 60-day intervals.

## 2.8. Brix and pH

The Brix was measured using a digital refractometer at 21 °C (Atago, Japan) and the pH was determined using a calibrated pH meter, with the calibration performed at pH 4 and pH 7 before every measurement to ensure precision.

## 2.9. Analysis of aroma compounds by GC-MS

The analysis of aroma compounds followed the standard method BVL L 00.00–106:2006–12 (BVL, 2006). Simultaneous distillation extraction was performed on 150 g of sample with qualitative and quantitative standards added, and pH adjusted to 7 before distillation. The samples were distilled for 1 h and 50 min, with a solvent mixture of diethyl ether and pentane (1:1). The extracts were analysed the same day using an Agilent 8890 gas chromatography (GC) system coupled with a 5977B GC-MSD (Agilent Technologies, USA) and a Rtx-VMS column (Restek, USA). Hydrogen was the carrier gas at 1.6 mL/min, with a 2 µL injection at 220 °C. The scan rate was set at 2.0 scan/s, the ionisation energy was set at 70 eV, and the mass scan range was set at 50–500 m/z. Mass spectrometric data for nineteen selected aroma markers were acquired using calibration curves (R² > 0.99). Identification was performed by comparing GC-MS spectra with commercial libraries (NIST 11 and FFNSC 4) and matching retention times to authentic standards. Quantification was based on relative peak areas, using an internal standard and sample weight, with concentrations reported in micrograms per litter (µg/L) of nectar. To ensure reliability, a control sample was analysed with each batch, and results were cross-checked with an accredited laboratory (Labor Dr. Haase-Aschoff, Germany).

## 2.10. Analysis of phenolic compounds by HPLC-PDA-MS

The analysis of individual phenolic compounds in the nectar samples was conducted at 25 °C following the method of Mikulic-Petkovsek et al. (2012). A high-performance liquid chromatography (HPLC) system (Finnigan Surveyor, Thermo Fischer Scientific, San Jose, USA) was used, equipped with both a photodiode array detector (PDA) and a mass spectrometer (MS) for compound detection. The separation was carried out using a Gemini C18 column (Phenomenex, Torrance, USA). Phenolic compounds were detected in both positive ionization mode for anthocyanins and negative ionization mode for other phenolic compounds. Data-dependent MSn scanning was performed from m/z 115 to 1900. Data processing was carried out using Thermo Scientific™ Xcalibur™ TM 4.3 software (Thermo Scientific, Waltham, USA). Phenolic compounds were identified using a multi-step approach to ensure accuracy. First, retention times and UV–Vis spectra (PDA) from detected peaks were matched against authentic phenolic standards analysed under the same conditions. Second, MS data were examined for characteristic
fragmentation patterns, which were then compared to published MS/MS spectra and database references. For quantification, standard curves were prepared for each identified phenolic compound. Total phenolic concentration was expressed in milligrams per liter (mg/L) of nectar.

## 2.11. Data analysis

Data were presented as means ± standard deviation based on four sample measurements. Statistical differences were tested using Jamovi software (version 2.3.28.0). One-way ANOVA was applied to determine statistical significance on treatment and storage time, followed by Tukey's Honest Significant Differences test for post-hoc comparisons. Principal Component Analysis (PCA) and cluster analysis were performed using RStudio (version 2024.04.1, Posit Software, PBC, Boston, USA) with the FactoMineR package (version 2.11). Data were normalised prior to analysis to ensure comparability between variables.

# 3. Results and discussion

All samples were thawed overnight at 4 °C prior to analysis for aroma and phenolic compounds. After complete thawing, measurements were taken on both untreated and treated samples. The untreated samples served as controls and were analysed immediately. For the treated samples, analyses were conducted at three different time points: immediately after treatment (day 0), after 30 days of refrigeration, and after 60 days of refrigeration. This approach allowed for the evaluation of both the immediate effects of the treatment and the stability of the samples over refrigerated storage.

## 3.1. pH and brix measurements

The pH and Brix of all samples were measured to assess any potential influence on the phenolic content and aroma profile. Across all treatments and storage times, no significant changes in pH or Brix were observed compared with the control samples. The pH values remained constant at 3.25 ± 0.18 while the Brix values were stable at 12 ± 0.2. Given these stable values, any changes in phenolic and aroma compounds cannot be attributed to variations in pH or Brix levels in the nectar.

## 3.2. Analysis of aroma compounds

### 3.2.1. Effect of processing methods and storage time on total aroma compounds

The changes in total aroma compounds resulting from processing

<figure><img src="image_2.png" /><figcaption>**Fig. 1.** Total aroma compounds (mg/L) in strawberry nectar. Lowercase letters indicate differences between treatments at the same time point, and uppercase letters indicate differences within the same treatment over time.</figcaption></figure>

with TP, OH, HPP, and PEF during storage are shown in Fig. 1. Immediately after treatment (day 0), HPP samples showed no significant differences to the control samples (5.29 ± 0.03 mg/L). OH, and PEF treatments followed, with no significant differences between them, and finally, TP showed the lowest values, with 2.94 ± 0.13 mg/L. The reduction in total aroma compounds observed in TP and OH samples could be attributed to thermal degradation, because of the direct exposure to high temperatures during processing (Sampedro et al., 2009). Previous studies have shown that temperature can result in significant losses of the total volatile organic compounds in fruit purees due to evaporation (Ubeda et al., 2014). Similarly, PEF may also induce a thermal effect due to ohmic heating effect during treatment (Thamsuaidee et al., 2024), which could potentially lead to a reduction in volatile compounds, although its impact is generally lower compared to conventional thermal processing. In contrast, HPP has been shown to better preserve aroma compounds in strawberry products (Gao et al., 2016).

For all treatments, there was a clear decline in the concentration of aroma compounds after 30 days of storage. The highest retention of aroma compounds during storage was observed with PEF treatment, while the greatest drop occurs in HPP samples, with a 41.62 % loss from day 0–60. Despite this significant reduction, HPP still maintains higher aroma content compared to thermal treatments (OH and TP). By 60 days OH, and TP show similar aroma compound levels, both being lower than PEF and HPP. Non-thermal technologies retain more volatile compounds than thermal methods, but time and storage conditions still play a role in degradation.

The significant reduction in aroma compounds on TP, is consistent with other studies where thermal treatments are reported to cause degradation of heat-sensitive compounds, including aroma volatiles (Patras et al., 2009; Yildiz et al., 2021). Additionally, the direct and prolonged heat exposure in TP likely leads to degradation reactions, contributing to the decline in aroma levels. This result confirms the understanding that thermal processing, while effective for microbial inactivation, often affects quality (Klopotek et al., 2005). Samples treated with OH show better retention of aroma compounds compared to TP, especially immediately after treatment. The reduced thermal gradient in OH is likely responsible for the better preservation of aroma compounds, making OH a favourable option over thermal. The moderate retention of aroma compounds in PEF samples at day 0 is in line with the results of Aguiló-Aguayo et al. (2009), who showed that PEF treatments generally preserve sensitive compounds better than thermal methods but still lead to degradation. The reduction of aroma compounds could be attributed to chemical reactions triggered by the mild thermal effects of PEF processing (Ayala-Zavala et al., 2004). HPP ability to maintain higher levels of aroma compounds compared to TP and PEF immediately after treatment is consistent with studies by Aaby et al. (2018) and Cao et al. (2012). HPP effect is explained due to its non-thermal nature and to the fact that the product is packaged before treatment, minimizing the loss of volatile compounds. Nevertheless, long-term storage leads to gradual degradation due to enzymatic activity or oxidative changes.

### 3.2.2. Cluster analysis and Principal Component Analysis (PCA) of aroma compounds

The heat map in Fig. 2 illustrates the clustering of strawberry nectar samples based on 19 aroma compounds analysed by GC-MS. The colour gradient ranges from light blue (low concentration) to dark blue (high concentration). Two-way Ward's cluster analysis was applied to group aroma profiles according to processing methods (TP, OH, HPP, PEF, and control) and storage times (d00, d30, d60). The Euclidean distance was used to measure the similarity between aroma profiles. The dendrogram on the x-axis organizes samples into six distinct clusters that show how processing methods and storage time influence the aroma profiles.

HPP-treated samples on day 0 (HPP.d00) and untreated control samples form a single cluster, indicating that HPP maintains similar
<figure><img src="image_3.png" /><figcaption>**Fig. 2.** Heatmap and cluster analysis of aroma compounds in strawberry nectar: treatments (TP, OH, HPP, PEF, control) and storage times (d00, d30, d60).</figcaption></figure>

aroma profile immediately after treatment. Samples from 30 to 60 days in all treatments cluster together, suggesting that storage time has a consistent impact on the aroma compounds. PEF-treated samples on day 0 (PEF.d00) are grouped separately but remain close to HPP.d00 and control samples, indicating a similar aroma profile at the start of storage. In contrast, all OH-treated samples are distinctly isolated from the other treatments, reflecting a unique aroma profile. Lastly, PEF-treated samples from days 30 (PEF.d30) and 60 (PEF.d60) cluster together and show a similar aroma profile to the thermally treated samples, which form the last cluster. The clustering pattern can be explained by the specific composition of certain aroma compounds. For instance, untreated samples (control), TP.d00, and HPP.d00 show higher levels of

mesifuran, whereas its concentration decreases in older samples. Mesifuran is a key aroma compound in strawberry and an indicator of ripe and overripe fruit stages (Simkova et al., 2024). A general decrease in aroma content over the storage period, is observed for several compounds, particularly in PEF and TP samples. Notable compounds showing variation between treatments and storage time include nonanal, which is elevated in OH.d00 and decrease over time, methyl cinnamate, which is particularly high in HPP.d30 but lower in other treatments, and cis-3-hexenol, which is notably lower in thermally treated samples compared to control and other treatments.

The score plot (Fig. 3B), which includes 75 % confidence ellipses, shows a clear separation between treatments, indicating that processing

<figure><img src="image_4.png" /><figcaption>**Fig. 3.** Principal component analysis (PCA) of aroma compounds in strawberry nectar: loading plot (A) and score plot (B) for the first two Principal Components (PC1 and PC2). In (A), the green circles represent different aroma compounds. In (B), treatments: ■ untreated (UT), ● thermal pasteurization (TP), ▲ PEF, ▼ ohmic heating (OH); ♦ HPP.</figcaption></figure>
techniques significantly influence the aroma profile of strawberry nectar. TP samples form a distinct group in the lower right quadrant of the first Principal Component (PC1), while OH-treated samples are in the upper right quadrant, reflecting a unique aroma profile compared to other treatments. PEF-treated samples overlap with HPP samples and are positioned near the centre. The PCA analysis further emphasizes the distinct profiles of thermal methods (TP and OH) compared to non-thermal methods (PEF and HPP). PC1, which accounts for 64.1 % of the total variance, clearly differentiates samples by storage time: untreated (control) and day 0 samples are positioned on the left, while older samples are on the right. Notably, PEF and HPP samples group closer to the control, with HPP showing greater similarity. Additionally, there is a noticeable variability within the treatments, particularly for PEF treated samples, which exhibit a wider spread compared to the tighter clustering of TP and OH samples. The tight clustering of TP and OH samples indicate less variability over time, reflecting a more stable effect on aroma profiles. In Fig. 3A variables with $cos^2 > 0.85$ are labelled and marked with arrows.

### 3.2.3. Overview of key aroma compounds

Nine key compounds, labelled and marked with arrows in Fig. 3A and listed in Table 1, were identified as important markers in the aroma composition across the different processing treatments and storage times. These key compounds were selected based on their percentage contribution to the first two principal components (PC1 and PC2) in the PCA analysis. The threshold for selection was set at a cosine value greater than 0.98, which helped identify the compounds most strongly associated with the variations in aroma profiles. A detailed overview of the 19 aroma compounds identified in strawberry nectar, including their relative abundances over time and categorized by their chemical type (aldehydes, esters, furanones, lactones, and terpenes) is presented in Table A1.

Significant variations in the concentration of specific aroma compounds were observed between treatments. For instance, methyl and ethyl butyrate, two of the most important esters in strawberry (Liu et al., 2016), show the highest concentration in the control samples, while TP greatly reduces their concentration. An especially high reduction is observed for hexyl acetate, in the TP samples, with a decrease of 91.8 % after treatment and a significant reduction also in OH. This confirms that heating has a considerable impact on the volatile profile. The quantity of aroma compounds does not directly correlate with product quality; however, certain volatile organic compounds (VOCs) are strongly associated with increased consumer sensory preference (Fan et al., 2021). Esters are the dominant contributors to the fruity and floral aromas of strawberries, significantly influencing their sensory appeal; compounds such as ethyl butyrate, methyl butyrate, and hexyl acetate had been linked to consumer likeness (Jouquand et al., 2008; Negri et al., 2015). Recent studies have linked consumer preference in

strawberry to specific VOCs that enhance flavour intensity. For instance, γ-dodecalactone have been identified as drivers of both sweetness perception and overall liking (Fan et al., 2021). In this study, control and PEF samples present a higher content of this lactone compared with the other treatments.

### 3.3. Analysis of phenolic compounds

#### 3.3.1. Effect of processing methods and storage time on total phenolic content

Fig. 4 presents the quantitative HPLC-MS data analysis for over 40 phenolic compounds, grouped by treatment and storage time. The full list of identified compounds, including molecular ion (m/z) and MS² (m/z) data for structural confirmation, is provided in Supplementary Table A2. The compounds were grouped as anthocyanins, flavones, flavanones, flavanols, hydroxycinnamic acids, ellagitannins, and hydroxybenzoic acids (HBAs). Anthocyanins emerged as the most significant group, comprising between 38.5 % and 56.7 % of the total phenolics in the samples. The second most abundant group identified in the analysis were the Flavanols.

The total phenolic content (TPC), as shown in Fig. 4, varied significantly across treatments and storage times. Immediately after processing, HPP, PEF, and OH samples had the highest TPC levels, while TP-treated samples showed the lowest TPC. All treatments, except TP, increased phenolic content compared to the initial untreated levels. By day 30, thermal-treated samples (TP) had lower TPC levels than non-thermal treatments. However, by day 60, no clear differences in TPC were observed between TP, OH, and HPP treatments, indicating a convergence in phenolic levels over time. This suggests that while non-thermal treatments initially enhance phenolic compounds, their effects diminish with prolonged storage. Notably, HPP samples experienced the most significant in TPC, with a loss of -28.0 % from day 0 to day 60. In general, storage time had the greatest impact on anthocyanins. Phenolic degradation occurred consistently across all treatments. While other studies have highlighted the effectiveness of non-thermal treatments like HPP and PEF in preserving phenolic compounds in strawberry nectar (Patras et al., 2009), the results of this experiments showed that, although initial levels were higher after non-thermal treatments, they were comparable to other methods by the end of the storage period.

Anthocyanins were the dominant phenolic compounds found in strawberry nectar. These pigments are highly sensitive to processing and storage conditions (Cao et al., 2012). The four primary anthocyanins identified were cyanidin 3-O-glucoside, pelargonidin 3-O-glucoside, pelargonidin 3-O-rutinoside, and pelargonidin 3-O-malonyl hexoside, with pelargonidin 3-O-glucoside being the most abundant, accounting for up to 81 % of the total. Typically, pelargonidin 3-O-glucoside is the most abundant anthocyanin and is more concentrated in fresh strawberries than in stored or processed (Barba et al., 2013; Sirijan et al.,

<caption>**Table 1**</caption>

Key aroma compounds found in strawberry nectar: odour description and concentration (µg/L) across different methods (TP: Thermal Pasteurization, OH: Ohmic Heating, HPP: High-Pressure Processing, PEF: Pulsed Electric Fields) after treatment (day 0).

<table><thead><tr><th rowspan="2">Group</th><th rowspan="2">Compound</th><th rowspan="2">Odour description</th><th colspan="5">Concentration (µg/L)*</th></tr><tr><th>control</th><th>TP</th><th>OH</th><th>HPP</th><th>PEF</th></tr></thead><tbody><tr><td rowspan="2">Aldehyde</td><td>Hexanal</td><td>Fatty, grass [1]</td><td>229.1 ± 49.3a</td><td>66.9 ± 19.1b</td><td>96.9 ± 68.4b</td><td>113.3 ± 34.6b</td><td>217.2 ± 69.2a</td></tr><tr><td>Nonanal</td><td>Waxy, aldehydic [1,4]</td><td>37.5 ± 5.3a</td><td>21.3 ± 1.9c</td><td>27.6 ± 1.8b</td><td>39.4 ± 4.8a</td><td>28.7 ± 1.5b</td></tr><tr><td rowspan="2">Ester</td><td>Hexyl acetate</td><td>Green, fruity [4]</td><td>40 ± 17.3a</td><td>4.3 ± 0.7c</td><td>15.9 ± 15.3b</td><td>31.7 ± 3.2a</td><td>40.6 ± 14.3a</td></tr><tr><td>Methyl butyrate</td><td>Fruity, sweet [1,3]</td><td>514.9 ± 140.6a</td><td>93.1 ± 7.3c</td><td>270 ± 166.2b</td><td>587.7 ± 72.9a</td><td>534.2 ± 99a</td></tr><tr><td rowspan="2">Furanone</td><td>Ethyl butyrate</td><td>Fruity, sweet [1,3]</td><td>279 ± 104.1a</td><td>49.8 ± 1.7c</td><td>187.4 ± 85.1b</td><td>219.7 ± 19.2a</td><td>336.9 ± 51.5a</td></tr><tr><td>Mesifurane</td><td>Sweet, berry [3]</td><td>1743 ± 187a</td><td>1347 ± 243b</td><td>1286 ± 230b</td><td>997.7 ± 94.8b</td><td>1345 ± 522b</td></tr><tr><td rowspan="2">Lactone</td><td>γ-dodecalactone</td><td>Sweet, fruity [4]</td><td>164.4 ± 27.1a</td><td>78.3 ± 13.8b</td><td>100.1 ± 26.8b</td><td>98.3 ± 10.4b</td><td>145 ± 21.8a</td></tr><tr><td>γ-decalactone</td><td>Fatty, peach [4]</td><td>595.4 ± 119.9a</td><td>405.1 ± 28.6b</td><td>355.6 ± 90.9b</td><td>341.6 ± 29.1b</td><td>610.7 ± 87.7a</td></tr><tr><td rowspan="2">Terpene</td><td>Linalool</td><td>Sweet, floral [2,4]</td><td>67.2 ± 8.5a</td><td>38.9 ± 1.9d</td><td>54.5 ± 6.7b</td><td>47.9 ± 2.4c</td><td>64.9 ± 6.4a</td></tr><tr><td>Trans-nerolidol</td><td>Floral, green [2,4]</td><td>432.4 ± 66.7a</td><td>175.8 ± 42.6c</td><td>312.5 ± 39.4b</td><td>272.3 ± 35.7b</td><td>398.5 ± 51.4a</td></tr></tbody></table>

<footnote>*mean ± standard deviation. Lowercase letters indicate significant differences between treatments for each aroma compound (p < 0.05). Odour descriptors are based on references [1–4], where 1 corresponds to Zhu et al., 2017, 2 to Wang et al., 2023, 3 to Fan et al., 2021, and 4 to Abouelenein et al., 2023.</footnote>
<figure><img src="image_5.png" /><figcaption>**Fig. 4.** Total phenolic compounds (mg/L) in strawberry nectar across treatments and storage times (0, 30, and 60 days) at 4 °C. Lowercase letters indicate differences between treatments at the same time point, and uppercase letters indicate differences within the same treatment over time.</figcaption></figure>

2020). However, in this study, HPP and PEF samples exhibited the highest levels of pelargonidin 3-O-glucoside, higher than control samples. Previous researchers have also shown that total anthocyanin content tends to increase in red fruit juices after HPP treatment (Gao et al., 2016; Patras et al., 2009) and PEF treatment (Stübler et al., 2020), likely due to enhanced extraction and cell disruption caused by these non-thermal technologies. Anthocyanins in strawberries are closely associated with colour stability (Murray et al., 2024). Identified anthocyanins play a significant role in determining the fruit's colour (Simkova et al., 2024) and its degradation can lead to a loss of colour intensity and potentially affect the nutritional quality of the product (Koubaa et al.,

2018).

### 3.3.2. Principal Component Analysis (PCA) of phenolic compounds

The PCA plot (Fig. 5.) illustrates the distribution of phenolic compounds in strawberry nectar across different treatments (HPP, OH, PEF, TP, and control) and storage times (0, 30, and 60 days). The first principal component (PC1) explains 68.2% of the variance, while the second principal component (PC2) explains 9.9%, indicating that PC1 is the primary factor driving the separation of the data.

TP samples (green) are clearly separated from the other treatments. This indicates that the thermal treatment results in a distinctly phenolic

<figure><img src="image_6.png" /><figcaption>**Fig. 5.** Principal component analysis (PCA) of phenolic compounds in strawberry nectar: loading plot (A) and score plot (B) for the first two Principal Components (PC1 and PC2). In (A), the blue circles represent different aroma compounds. In (B), treatments: ■ untreated (UT), ● thermal pasteurization (TP), ▲ PEF, ▼ Ohmic heating (OH), ◆ HPP.</figcaption></figure>
composition, particularly immediately after the treatment, confirming that thermal processing induces changes in phenolic content (Klopotek et al., 2005). Control samples (light blue) are clustered tightly on the left side of the plot and non-thermal treatments (HPP, PEF) are more closely clustered together with OH samples, suggesting that these methods preserve the phenolic content likewise. The clear separation of TP and OH samples suggests that the traditional thermal process causes more immediate and significant alterations to the phenolic profile compared to the fast heating of Ohmic. In general, non-thermal treatments tend to preserve phenolics more effectively (Cao et al., 2011), as evidenced by their closer grouping with untreated samples. However, over time (30 and 60 days), the phenolic composition in these treatments drifts towards the right along PC1, reflecting the effects of storage time. All samples measured at time 0 (before and immediately after treatment) were clustered on the left side (negative values on PC1). In contrast, samples stored for 30 and 60 days were clustered in the right side (positive values on PC1). This suggests that storage time significantly influences the phenolic profile (Kadivec et al., 2013).

### 3.3.3. Overview of key phenolic compounds

Table 2 presents a detailed overview of the major phenolic compounds identified in strawberry nectar, including their relative abundances and molecular grouping. The key phenolic compounds, showed and named in Fig. 5A, were identified from the eigenvalues of the first two components. Anthocyanins, particularly pelargonidin-3-rutinoside, exhibit higher levels in the nectar subjected to HPP compared to other treatments, with the lowest levels observed in TP samples. Pelargonidin-3-rutinoside is a key anthocyanin in strawberries, contributing significantly to their red coloration and antioxidant properties (Milosavljević et al., 2022). For bis-HHDP-hexoside 2, PEF retains the highest levels (1.35 ± 0.04 mg/L). Interestingly, HPP caused the most significant reduction in this compound, with a 36.3 % decrease compared to the control sample.

In general, several compounds increased after non-thermal treatments. Studies have shown that processing methods like HPP can enhance the extraction and bioavailability of phenolic compounds due to cell wall disruption, which may explain the elevated levels observed in treated samples (Cao et al., 2011; Gao et al., 2016; Vanga et al., 2019). A contrasting effect observed in the same samples, has been previously published (Zia et al., 2025), where increased vitamin C levels were observed in TP, compared with PEF, HPP and OH.

## 4. Conclusions

This study presents a comparative analysis of novel technologies, against traditional thermal pasteurization, focusing on their effects on

the aroma and phenolic compounds in strawberry nectar, all subjected to equivalent treatment. HPP and PEF-treated samples retained higher levels of key aroma compounds compared to thermally processed samples immediately after treatment. The retention of these aroma markers is crucial for maintaining the sensory appeal of the nectar. However, during storage, HPP and PEF samples did not retain these compounds as effectively as OH and thermal-treated samples. This suggests that while non-thermal methods excel in preserving aroma compounds initially, their performance diminishes during storage. The study found that anthocyanins, especially pelargonidin-3-rutoside, were sensitive to thermal degradation, with TP leading to the greatest losses. HPP, PEF and OH showed the highest content of phenolic compounds after treatment. Ohmic heating demonstrated improved phenolic preservation compared to traditional pasteurization, likely due to its more uniform and fast heating. In conclusion, although all processing methods achieved the required microbial inactivation, non-thermal treatments emerged as most effective for preserving both the aroma and phenolic profiles of strawberry nectar. The findings from this study highlight the potential of HPP, PEF, and OH as promising alternatives to thermal pasteurization for enhancing the shelf life and nutritional quality of fruit-based beverages. These results lay a strong foundation for future research aimed at exploring practical aspects such as energy efficiency, cost-effectiveness, and equipment scalability, ultimately supporting the broader adoption of these innovative technologies in the food industry.

### CRediT authorship contribution statement

**Dario Pavón-Vargas:** Conceptualization, Formal analysis, Writing – original draft, Visualization, Investigation, Writing – review & editing, Methodology, Data curation. **Krystina Simkova:** Methodology, Conceptualization, Investigation, Formal analysis, Data curation. **Alema Puzović:** Formal analysis, Investigation, Methodology, Data curation, Conceptualization. **Andres Moreno-Barreto:** Conceptualization, Investigation, Methodology. **Astrid Gědas:** Methodology, Conceptualization. **Helen Murray:** Methodology, Investigation, Conceptualization. **Ibrahim Rabeeah:** Methodology, Conceptualization. **Sebastian Rincon:** Methodology, Investigation, Conceptualization. **Ngoc Quynh Anh Truong:** Visualization, Data curation, Writing – review & editing. **Alberto Zavarise:** Methodology, Conceptualization. **Hassan Zia:** Methodology, Investigation, Conceptualization. **Luca Sandei:** Supervision, Resources, Conceptualization. **Massimiliano Rinaldi:** Validation, Resources, Conceptualization. **Stephane Georgé:** Validation, Resources, Conceptualization. **Mario Gozzi:** Resources, Funding acquisition, Conceptualization, Supervision. **Manfred Gössinger:** Supervision, Resources, Conceptualization, Writing – review & editing, Funding acquisition. **Severin Guski:** Conceptualization, Resources. **Stefan

<caption>**Table 2**</caption>

Key Phenolic Compounds found in strawberry nectar by concentration (mg/L), across different treatments (UT: Untreated, TP: Thermal Pasteurization, OH: Ohmic Heating, HP: High-Pressure Processing, PF: Pulsed Electric Fields) after treatment (day 0).

<table><thead><tr><th rowspan="2">Class</th><th rowspan="2">Group</th><th rowspan="2">Compound</th><th colspan="5">Concentration (mg/L)<sup>a</sup></th></tr><tr><th>control</th><th>TP</th><th>PEF</th><th>OH</th><th>HPP</th></tr></thead><tbody><tr><td rowspan="8">Flavonoids</td><td>Anthocyanins</td><td>Pelargonidin 3-rutinoside</td><td>36.81 ± 0.82b</td><td>26.43 ± 1.77c</td><td>36.45 ± 2.83b</td><td>38.08 ± 2.21b</td><td>41.45 ± 1.14a</td></tr><tr><td>Flavanols</td><td>Procyanidin trimer 5</td><td>41.02 ± 4.99b</td><td>56.36 ± 2.52a</td><td>58.96 ± 6.63a</td><td>56.9 ± 2.8a</td><td>52.32 ± 2.61a</td></tr><tr><td>Flavanones</td><td>Cinnamoyl-hexose</td><td>29.44 ± 0.47d</td><td>38.15 ± 0.21a</td><td>30.60 ± 0.23c</td><td>31.54 ± 0.10b</td><td>30.27 ± 0.35c</td></tr><tr><td rowspan="4">Flavonols</td><td>Naringenin-hexoside 1</td><td>1.59 ± 0.09b</td><td>1.69 ± 0.11a,b</td><td>1.77 ± 0.14a,b</td><td>1.79 ± 0.05a,b</td><td>1.97 ± 0.08a</td></tr><tr><td>Naringenin-hexoside 3</td><td>0.78 ± 0.01b</td><td>0.67 ± 0.02c</td><td>0.81 ± 0.01a</td><td>0.83 ± 0.0a</td><td>0.78 ± 0.01b</td></tr><tr><td>Naringenin-hexoside 4</td><td>1.9 ± 0.06b</td><td>1.36 ± 0.02c</td><td>2.02 ± 0.04a</td><td>2.04 ± 0.02a</td><td>1.85 ± 0.04b</td></tr><tr><td>Isorhamnetin 3-rhamnoside</td><td>5.67 ± 0.1b</td><td>4.86 ± 0.12c</td><td>5.88 ± 0.08a</td><td>6.04 ± 0.03a</td><td>5.65 ± 0.07b</td></tr><tr><td rowspan="5">Phenolic acids</td><td rowspan="3">Hydroxycinnamic acids</td><td>Kaempferol-hexoside</td><td>0.69 ± 0.12</td><td>0.74 ± 0.11</td><td>0.57 ± 0.36</td><td>0.76 ± 0.07</td><td>0.67 ± 0.27</td></tr><tr><td>Quercetin 3-O-glucuronide</td><td>0.99 ± 0.25a</td><td>0.67 ± 0.03b</td><td>1.12 ± 0.21a</td><td>0.93 ± 0.01a</td><td>1.18 ± 0.21a</td></tr><tr><td>Quercetin 3-O-rhamnoside</td><td>2.45 ± 0.04b</td><td>2.1 ± 0.05c</td><td>2.54 ± 0.04a</td><td>2.61 ± 0.01a</td><td>2.44 ± 0.03b</td></tr><tr><td rowspan="2">Ellagitanins</td><td>5-p-Coumaroylquinic acid 1</td><td>3.86 ± 0.18b</td><td>3.58 ± 0.07c</td><td>4.25 ± 0.17a</td><td>4.53 ± 0.12a</td><td>4.28 ± 0.06a</td></tr><tr><td>5-p-Coumaroylquinic acid 2</td><td>1.77 ± 0.03b</td><td>1.3 ± 0.01c</td><td>1.89 ± 0.04a</td><td>1.94 ± 0.01a</td><td>1.86 ± 0.01a</td></tr><tr><td></td><td></td><td>bis-HHDP-hexoside 2</td><td>1.35 ± 0.28a</td><td>1.05 ± 0.43a,b</td><td>1.35 ± 0.04a</td><td>1.32 ± 0.11a</td><td>0.86 ± 0.12b</td></tr><tr><td></td><td></td><td>Galloyl-bis-HHDP-hexoside 1</td><td>18.78 ± 2.28b</td><td>25.8 ± 1.15a</td><td>26.99 ± 3.03a</td><td>26.05 ± 1.28a</td><td>23.95 ± 1.2a</td></tr></tbody></table>

<footnote>a mean ± standard deviation. Lowercase letters indicate significant differences between treatments at day 0, for each aroma compound (p < 0.05).</footnote>
**Humel:** Conceptualization, Resources. **Jerneja Jakopic:** Funding acquisition, Supervision, Methodology, Resources, Conceptualization. **Carine Le Bourvellec:** Funding acquisition, Resources, Supervision, Conceptualization. **Sara Rainieri:** Funding acquisition, Resources. **Maja Mikulic-Petkovsek:** Resources, Supervision, Funding acquisition, Methodology, Conceptualization. **Agnes Weiss:** Conceptualization, Funding acquisition, Resources. **Marc Schmidt:** Conceptualization, Resources. **Francesco Guareschi:** Conceptualization, Resources. **Christian Molitor:** Resources, Conceptualization, Supervision, Writing – review & editing, Project administration, Funding acquisition. **Mikko Hofsommer:** Conceptualization, Resources, Supervision, Funding acquisition. **Ana Slatnar:** Funding acquisition, Supervision, Conceptualization, Resources. **Heidi Halbwirth:** Project administration, Supervision, Validation, Conceptualization, Writing – review & editing, Funding acquisition, Resources. **Luca Cattani:** Supervision, Conceptualization, Methodology, Project administration, Writing – review & editing, Resources, Validation, Funding acquisition.

## Funding

The project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 956257.

## Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

To clarify, Dario Pavon-Vargas is a PhD student at the University of Parma and reports receiving funding as part of the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu) from CFT SpA, which involves a partnership between the university and the company. Mario Gozzi serves as his advisor within CFT SpA.

Andres Moreno-Barreto was a PhD student at the University of Parma and reports receiving funding as part of the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu) from SSICA, which involves a partnership between the university and the research centre. Luca Sandei serves as his advisor within SSICA.

Hassan Zia was a PhD student at the University of Ljubljana and reports receiving funding as part of the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu) from GFL, which involves a partnership between the university and the company. Mikko Hofsommer serves as his advisor within GFL.

Helen Murray is a PhD student at TU Wien university and reports receiving funding as part of the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu) from HBLA und BA für Wein-und Obstbau, which involves a partnership between the university and the company. Manfred Gössinger serves as his advisor within HBLA und BA für Wein-und Obstbau.

Severin Guski, Stefan Humel work for Austria Juice GmbH, a company involved in the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu).

Marc Schmidt works for ELEA Technology GmbH, a company involved in the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu).

Francesco Guareschi works for HPP Italia Srl, a company involved in the Marie Skłodowska-Curie project HiStabJuice (histabjuice.eu).

This research is part of a Marie Skłodowska-Curie Actions ITN (MSCA-ITN) project, which involves collaboration with industrial partners (histabjuice.eu). The research was conducted using pilot plant facilities. The use of the pilot plant and industry collaboration are part of the standard MSCA-ITN framework, which aims to boost academia-industry partnerships. The authors declare that this research grant and industrial collaborations provide funding and academic support for the work but do not create any conflict of interest for the authors or

influence the research outcomes. This arrangement is part of the European Union's initiative to foster academia-industry partnerships and enhance doctoral training.

## Acknowledgments

We would like to express our sincere gratitude to the institutions that contributed to this research. CFT Spa (Parma, Italy) for the thermal treatment and CTCPA (France) for the OH experiments. We also acknowledge the support of HPP Italia (Traversetolo, Italy) for the HPP treatment and ELEA (Klosrenburg, Germany) for the PEF treatments. Their cooperation and expertise were invaluable to the successful completion of this study.

## Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.lwt.2025.118066.

## Data availability

Data will be made available on request.

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