Cinnamomum cassia barks (Chinese cinnamon) was used as a source material for extracting EO, and the bark was purchased from a reputable local herbalist in Bordj Bou-Arréridj, Algeria. Before the extraction process, the bark was thoroughly cleaned to eliminate surface contaminants. Then it was crunched to increase its surface area for extraction. CCEO extraction was carried out by hydro-distillation in a Clevenger-type apparatus. Briefly, 100 g of crushed C. cassia bark was hydrodistilled for 3 h with 500 mL of distilled water. After extraction, the EO was dried with anhydrous sodium sulfate, filtered, and stored in an opaque bottle at 4°C for analysis (Ramazani et al., 2020).

Organoleptic characteristics have a crucial role in determining the quality and potential uses of EO. The organoleptic quality of an EO and its potential for scientific and economic use are determined by its appearance, color and odor.

Fresh orange (Citrus sinensis) fruits of equal maturity were purchased in bulk from a local market (Bourj Bou Arrerij, Algeria). The fruit was delivered and inspected in the laboratory for physical damage or visible insects before being washed and gently wiped to remove contaminants. Oranges were sectioned and fresh juice was extracted using a domestic extractor (Condor JC115, Algeria). The juice was filtered through a fine mesh strainer (with a filter pore size of 10 μm) to remove seeds. Finally, the prepared orange juice samples were stored in clean and airtight containers and kept in a refrigerator at 4°C to prevent oxidation and microbial contamination.

To assess the effectiveness of CCEO in preserving orange juice, different doses (5, 10, 15, and 20 μL/L) were added to unpasteurized orange juice samples. These doses were selected based on the in vitro antioxidant and antifungal activity of CCEO. A negative control sample was also prepared (in all, five samples). The samples were homogenized using a vortex mixer. The samples were preserved at 4°C for 28 days to observe temporal variations. During this period, sensory analysis was performed to assess the juice’s flavor, fragrance, hue, and general acceptability. Furthermore, physicochemical and microbiological characteristics were evaluated during the entire storage period. Simultaneously, a sensory analysis was conducted to determine the effect of CCEO on the organoleptic properties (such as taste, aroma, color, and the overall acceptability) of orange juice samples.

A total of 21 trained panelists (aged 20–35 years) were recruited based on availability, prior sensory experience, and confirmed sensory acuity (Larmond, 1977). All panelists were selected based on the following criteria: trained panelists; no known allergies or health conditions affecting taste or smell; and successful completion of a sensory acuity screening, including basic taste and odor recognition. Taste perception is controlled by the gustatory cortex. Taste and smell determine flavor, which is the sensory impression of food or other materials. Food flavor can be modified by natural or artificial aromas that affect the senses. These differences in taste and flavor were discussed with panellists.

Orange juice samples were presented to panelists in a randomized manner. The samples were evaluated for color, taste, flavor, and the overall acceptability, because these parameters directly influence how consumers perceive and enjoy the product. Color is the first visual cue that affects consumer expectations and indicates freshness. Taste is critical for balance; orange juice should be sweet enough to be pleasant but also have enough acidity for freshness. A distinct flavor profile is indicative of high-quality juice. The overall acceptability integrates all sensory impressions (appearance, taste, flavor, mouth feel, etc.). The panelists were provided with a 9-point hedonic scale ranging from “like extremely” (9) to “dislike extremely” (1) to rate the orange juice samples for acceptability of four sensory attributes. The sensory sheet model is presented in Table 1. The panelists were instructed to evaluate each sample individually based on specified sensory attributes using the provided hedonic scale. The process also involved facilitating discussion among the panelists to identify differences in the acceptability of four sensory attributes of orange juice samples. Discussions encouraged the panelists to share their sensory perceptions and feedback on the evaluated attributes.

In this study, individuals participated on a voluntary basis and did not receive any compensation. Moreover, the sensory evaluation did not require formal ethical approval from Algerian National Committee on Health Research Ethics. However, consents from all the participants were obtained and appropriate protocols for protecting their rights and privacy were followed before and during the execution of the research.

Statistical analysis was performed using SPSS IBM Statistics 29.0.10 version. One-way ANOVA test followed by Tukey’s post hoc multiple comparison was performed to determine significant values (p < 0.05). All experiments were performed in triplicate and the results of statistical analysis were computed as mean ± standard deviation (SD).

The results of organoleptic and physical characterization of EO are presented in Table 2. The EO obtained was a clear, pale yellow liquid at room temperature, with a spicy sweet taste and pleasant characteristic odor and an aromatic flavor. Its density was 1.054±0.004, which was higher than distilled water (0.99), and was within the Association Française de Normalisation (AFNOR), 1999, standard range of 1.045–1.063. The refractive index was 1.6034, also higher than distilled water (1.33) and within the Association Française de Normalisation (AFNOR), 2000 range of 1.6020–1.6060. These results confirmed the purity of cinnamon EO. The yield obtained was 2.8% (w/w); which was relatively high, compared to our previous study (Boubrik et al., 2025).

Our findings were aligned with the results of the literature. Koroch et al. (2007) found that the extracted EO from commercial cinnamon barks was yellow with a spicy sweet taste and a relative density ranging from 1.019 to 1.026, and a refractive index ranging from 1.5817 to 1.5909. Similarly, Huang et al. (2019) obtained a pale yellow EO, with pleasant odor and strong or mild aroma spicy flavor, with a relative density of 0.998–1.067. In addition, Quyen and Quoc (2023) revealed that the extracted CCEO was a yellow liquid with a bitter and spicy taste and a characteristic odor, and a relative density of 1.047. Our results were close to those found by Boughendjioua and Djeddi (2018), confirming that EO from cinnamon was a clear liquid, yellowish in color, spicy sweet taste, and aromatic flavor, with a relative density of 1.050 and a refractive index of 1.6020.

Color, density, and refractive index are the essential characteristics of EO’s quality and purity. Color signals the presence of natural components or possible impurities; density helps to confirm whether the oil is pure or diluted; and refractive index is a sensible measure to reveal subtle changes in EO’s composition, making it useful for detecting adulteration. The data are especially valuable in deciding whether EO needs further purification or refinement before it could be used safely, particularly in sensitive applications such as food, medicine, and aromatherapy. However, EO undergoes rigorous analysis and complies with safety and purity standards. The results confirm that it is free from adulteration and suitable for use in food applications. The ongoing monitoring of these parameters remains essential for quality assurance; no further purification is required for our EO at this point of time.

The importance of using orange juice for human health depends on maintaining physical, chemical, and microbiological standards to ensure the quality and safety of the juice (Hossain et al., 2012). The results of CCEO impacts on the physicochemical and microbiological parameters of orange juice during 28 days of storage at 4±0.5°C are presented in Table 3. Pearson’s correlation coefficients between CCEO dose and the physicochemical and microbiological parameters of orange juice during storage are presented in Table 4.

Classification of Pearson’s correlation coefficients (R) is as follows: 0.00 and 0.199: very low; 0.20–0.399: low; 0.40–0.599: medium; 0.60–0.799: high; 0.80–1.00: very high.

The levels of vitamin C in orange juice samples treated with different doses of CCEO during storage are shown in Figure 2. The results indicate a significant enhancement (p < 0.05) in the level of ascorbic acid in the treated orange juice samples, compared to the control. The treated samples showed higher ascorbic acid levels with a range of 4.98–3.89 mg/100 mL for 20 μL, 4.82–3.73 mg/100 mL for 15 μL, 4.66–3.52 mg/100 mL for 10 μL, and 4.51–3.20 mg/100 mL for 5 μL, compared to the control, with a range of 4.27–2.11 mg/100 mL. However, there was a degradation of ascorbic acid over time because of oxidation and enzymatic activity. Furthermore, the study discovered moderate positive Pearson’s correlation coefficients between the dose of CCEO and vitamin C levels in orange juice samples. These statistically significant results indicated that higher doses of CCEO could help to maintain vitamin C content and the nutritional quality of orange juice over time.

Our results were consistent with a research conducted by Kapoor et al. (2011), who reported a significant enhancement in ascorbic acid of sweet orange juice treated with cardamom EO during storage. Similar findings were noted in case of fresh orange juice preserved with Cymbopogon citrate EO (Adjou et al., 2017). Our findings aligned with the results of a research conducted by Madhumita et al. (2021), who reported that cured betel leaf EO significantly improved the ascorbic acid content in sapota fruit juice.

A significant increase in the ascorbic acid content of treated orange juice samples could be due to the ability of EO to slow down oxidation and the enzyme ascorbinase (ascorbate oxidase) contributing to vitamin C preservation (Kapoor et al., 2011). However, during extended storage, orange juice loses ascorbic acid, changes color, and loses other nutrients. This happens because of dissolved oxygen that starts oxidation. Changes in temperature speed up this process, converting ascorbic acid to dehydroascorbic acid and then to inactive compounds, such as 2,3-diketogulonic acid (Sinchaipanit et al., 2015).

It is scientifically wrong to label cinnamon EO as an “enzyme inhibitor” without further studies supporting this claim. At most, the available data support the hypothesis that cinnamon EO may contribute to slowing the enzymatic activity, possibly through indirect effects (e.g., antioxidant or antimicrobial properties), but not necessarily by direct enzyme inhibition.

The results of TSS content (°Brix) in orange juice samples treated with various concentrations of CCEO during storage are shown in Figure 2. The results indicate a significant improvement (p < 0.05) in the level of TSS in the treated orange juice samples, compared to the control, except for the dose of 5 μL/L. The treated samples retained higher TSS levels, ranging from 13.60 to 8.50 °Brix for 20 μL, 13.60 to 6.50 °Brix for 15 μL, 13.60 to 5.60 °Brix for 10 μL, and 13.60 to 5.50 °Brix for 5 μL, compared to the control, which ranged from 13.60 to 4.90 °Brix, suggesting that CCEO contributed toward enriching the sugar profile of the juice. However, there was a decrease in TSS for all samples over storage. Furthermore, Pearson’s coefficient correlation between CCEO dose and TSS was positive and statistically significant. These statistically significant results indicated that higher doses of CCEO could help maintain the sugar content over time.

Our findings were in agreement with the research conducted by Charfi et al. (2019), who reported a significant enhancement in sugar contents of pomegranate juice treated with Thymbra capitata EO. Similarly, Madhumita et al. (2021) observed an enhancement in the TSS of sapota juice treated with cured betel leaf EO during storage. This rise in TSS was probably linked to fruit ripening process, where organic acids served as crucial respiratory substrates during postharvest storage.

The addition of EOs improves sugar content in orange juice because of the presence of phenols in EO that preserve sugars and protect these from degradation (Charfi et al., 2019). However, sugar content could decrease during storage because of microorganisms and acids (Sreedevi et al., 2020), creating reactive forms (e.g., HMF and/or 3-deoxyglucosone) that contribute to non-enzymatic browning (NEB; Pham et al., 2019).

The effect of CCEO on the sensory characteristics of orange juice is presented in Table 5 and Figure 5. Pearson’s correlation coefficients between CCEO dose and the sensory analysis of orange juice during storage are presented in Table 6. The results show a statistically significant improvement (p < 0.05) in the sensory attributes of color, taste, flavor, and the overall acceptability of juice samples treated with varying concentrations of CCEO, compared to the control. Color scores ranged from 8.43 to 6.80 for 20 μL, 8.33 to 6.50 for 15 μL, 8.33 to 4.50 for 10 μL, and 8.24 to 3.11 for 5 μL. Taste scores ranged from 7.96 to 5.99 for 20 μL, 7.99 to 5.73 for 15 μL, 6.85 to 5.20 for 10 μL, and 5.77 to 3.69 for 5 μL. Flavor scores ranged from 7.93 to 6.44 for 20 μL, 7.89 to 5.63 for 15 μL, 6.77 to 5.36 for 10 μL, and 5.86 to 4.40 for 5 μL. The overall acceptability scores ranged from 7.78 to 5.53 for 20 μL, 7.80 to 5.68 for 15 μL, 6.52 to 5.41 for 10 μL, and 5.86 to 4.69 for 5 μL. In contrast, the control samples recorded lower scores, ranging from 8.01 to 3.09 for color, 5.21 to 2.30 for taste, 5.69 to 2.51 for flavor, and 5.65 to 2.81 for overall acceptability. No significant difference (p > 0.05) was found between 15 μL/L and 20 μL/L doses during storage. The results indicated that samples treated with CCEO at concentrations of 20 μL/L and 15 μL/L achieved the highest sensory evaluation scores, with progressively lower ratings observed in samples treated with 10 μL/L and 5 μL/L CCEO concentrations. Higher CCEO concentrations were generally more acceptable to the sensory panel, as these levels help to reduce harmful microorganisms and enhance flavor, thereby improving the overall juice quality and consumer appeal. However, there was a decrease in the sensory scores of all samples over storage.

The results of Pearson’s correlations, as shown in Table 6, indicate moderate positive correlations between CCEO dose and color, taste, flavor, and the overall acceptability as well as statistically significant results. These findings suggested that the addition of CCEO significantly improved the sensory quality of orange juice, leading to enhancement in color, taste, flavor, and overall acceptability. These positive correlations underscored the potential of CCEO as a natural preservative and flavoring agent in fruit juice applications.

Cloudiness and turbidity are critical parameters influencing the sensory and visual appeal of juice that are important for its sensory and visual qualities, thus affecting the consumer perception. PMEs promote juice clearance over time by deesterification of pectin, lowering the viscosity, and influencing clarity and stability (Aghajanzadeh and Ziaiifar, 2018). Previous study showed that oxygen caused degradation of ascorbic acid in orange juice, resulting in loss in both color and quality during storage (Sinchaipanit et al., 2015). In addition, natural pigments and other reactions contributed to this degradation. EOs, such as Cinnamomum cassia EO, can improve orange juice’s color stability and physical characteristics by stabilizing the colloid system (Xu et al., 2020), and preventing oxidation (Kapoor et al., 2011) and microbial growth (Eissa et al., 2008).

A significant enhancement in taste could be related to preserving EO key compounds such as sugars and organic acids, which are vital for consumer acceptance. The EO preserves key flavor compounds, thereby enhancing the sensory profile of the juice. However, decrease in the taste score over time may be linked to lipid oxidation, which produces off-odors that harm taste characteristic (Madhumita et al., 2021). These off-odors are often associated with rancidity or spoilage, and negatively impact the taste characteristic, resulting in poor taste scores during sensory evaluation.

A significant enhancement in flavor could be related to the specific flavor components present in CCEO, such as coumarin, cinnamaldehyde (the main component responsible for the typical cinnamon flavor found in the oil), cinnamic acid, and cinnamyl alcohol, which create pleasant aroma and taste (Woehrlin et al., 2010). However, decrease in the flavor score over time is due to chemical reactions, such as enzymatic and NEB processes that turn juice brown and develop off-flavors (Paravisini and Peterson, 2018).

A significant improvement in the overall acceptability could be related to the improvement in color, taste, and flavor. However, decrease in the overall acceptability is due to browning, oxidation, and microbial activity that negatively impact sensory qualities of the juice, ultimately influencing consumer acceptance.

In contrast to our findings, Espina et al. (2014) found that increasing mint and rosemary EOs reduced acceptance in tomato juice and vegetable soup. In addition, Dwijatmoko et al. (2016) noted that high levels of CCEO in dark chocolate decreased consumer acceptance, highlighting the need for careful use of EOs. Similarly, a high concentration of CCEO used for Thomson navel orange fruit caused skin burns and the fruit was unacceptable by panel (Khorram and Ramezanian, 2021). However, even low concentrations of CCEO in an edible coating of apples harmed their flavor and aroma (Santos et al., 2018).

Researchers and food companies are focusing on creating cinnamon-based functional foods because of their potential health benefits. However, it is challenging to develop such foods because cinnamon has strong aromatic components that could potentially impact consumer acceptance (Dwijatmoko et al., 2016). To our knowledge, there is a lack of sensory evaluations specifically focusing on the incorporation of CCEO in orange juice. Furthermore, the existing literature on sensory analyses involving CCEO in food products often lacks comprehensive panel information or relies on smaller panel sizes. It is a critical consideration, as the demographic characteristics of panelists, such as age, food preferences, and gender, significantly influence the outcomes and interpretations of sensory studies.