Assessment of quality characteristics of Saudi honeys: Distinctive and rare types

1. Introduction

Honey is a complex mixture of substances, composed of around 80% carbohydrates (35% glucose, 40% fructose, and up to 5% sucrose) and 20% water. It is rich in over 200 components such as amino acids, vitamins, minerals, enzymes, organic acids, and phenolic compounds, making it an excellent source of energy (Tanuğur Samanci et al., 2024). These compounds can be introduced by bees or come directly from nectar due to the ripening process (Roshan et al., 2017). Since ancient times, honey has been cherished for its numerous health benefits, which stem from its unique physical and chemical properties, depending on the plant sources which bees can obtain nectar from, these traits can differ greatly. Different plants impart distinct flavors, colors, and even therapeutic qualities to honey (Baroni et al., 2009; Lacerda et al., 2010). The location of production, environmental factors, soil type, weather, and beekeepers’ procedures all affect the honey’s electrical conductivity (EC), moisture content (MC), free acidity (FA), pH value, color, hydroxymethylfurfural (HMF) content, and sugar composition. (Baroni et al., 2009).

Numerous investigations have shown that the chemical and physical characteristics of honey are strongly related to its botanical origin; several of these substances may serve as indicators to pinpoint a plant’s origin. (Devillers et al., 2004; Raweh, Ahmed, et al., 2022; Terrab et al., 2004). Saudi Arabia is rich in a diversity of plants, including floral plants, desert vegetation, as well as seasonal and annual herbs (Alqarni et al., 2017).

Physicochemical analyses that measure a variety of characteristics, including MC pH, EC, sugar content, acidity, color, HMF, and enzyme activity, can be used to evaluate the quality of honey. These indicators reveal the honey’s composition, purity, and quality assessment. (Alqarni et al., 2016; Pilizota and Tiban, 2009; Raweh, Badjah-Hadj-Ahmed, et al., 2022).

Despite the fact that honey is commonly utilized in Saudi Arabia for its nutritional and medicinal benefits, few studies have been conducted there to assess its quality. (Mohammed et al., 2017; Alqarni et al., 2016; Alqarni et al., 2014). Honey is more popular in Saudi Arabia due to its use in food, medicine, and natural mixtures. Without quality indicators, local honey varieties are exchanged, which could result in adulteration. Therefore, it is crucial to compare these honeys with quality criteria. In this regard, official authorities in Saudi Arabia are supporting the growth of the honey trade (Alotibi et al., 2018; Raweh et al., 2023). There are rare and distinctive honeys in Saudi Arabia whose properties have not been extensively studied yet. That’s why this study analyzed physicochemical parameters including MC, total soluble solids (TSS), total dissolved solids (TDS), pH, EC, FA, HMF, and Diastase activity (DN) to verify the origin and unique characteristics of honey from Saudi Arabia.

2. Materials and Methods

The studies were carried out in 2023 at King Saud University’s Melittology and Honey Quality Research Lab, Department of Plant Protection, College of Food and Agriculture Sciences, Riyadh, KSA. The Association of Official Analytical Chemists’ official standard methodologies were followed in the analysis of the honey samples’ physiochemical properties (AOAC, 1990). Physicochemical parameters such as MC, TSS, TDS, pH value, HMF, DN, EC, FA, and total sugar content were all evaluated in these tests.

3. Results

Results and descriptive statistics of physicochemical parameters for 12 honey samples (Tamarix sp., Achillea sp., Capparis sp., Hypericum sp., Calotropis sp., Moringa sp., Euphorbia sp., Anisosciadium sp., Avicennia sp., Acacia gerrardii sp., Ziziphus sp., Acacia ehrenbergiana), which were collected from different regions of Saudi Arabia, are summarized in Table 2. The results showed that the mean value of MC (16.3±0.29%), TSS (83.7±0.28 %), TDS (415±77.13 ppm), pH (4.0±0.30), EC (0.6±0.11 mS/cm), FA (36.6±5.79 meq/kg, HMF (15±3.74 mg/kg), and DN (13±1.60) of the honey samples (Table 2) were within the acceptable ranges according to international and national standards (Codex, 2001; GSO, 2014). ANOVA revealed significant differences in physicochemical parameters across the honey samples. The low MC indicates mature honey with minimal fermentation potential and a longer shelf life. The combination of low HMF and high DN indicates freshness and proper handling. Additionally, the higher electrical EC observed in Talh honey highlights its unique mineral composition, likely influenced by its botanical origin.

4. Discussion

The tested honey samples showed an average MC of 16.3±0.29%. The samples’ MC differed significantly. All of the samples met both national and international standards. A reduction in MC was linked to an increase in TSS (Table 2). These results are supported by Kamal et al. (2019) and (Primandasari et al. (2021).

Honey’s MC is affected by many factors, including environmental conditions, beekeeper practices during harvest, processing and storage, and the degree of maturity reached in the hive. Other factors, such as handling practices, weather, MC in the plant’s nectar and/or unripe honey, also contribute to an increase in MC of honey. (Alqarni et al., 2016; Geană et al 2020; Jalili, 2016; Osman et al., 2007). The present findings align with previous results of Raweh et al. (2023), who found that Saudi honey had MCs ranging from 13.1 ± 0.0 to 17.1 ± 0.1%. The average TSS of the tested honeys was 83.7±0.28% (Table 3), being within the permitted standards. Moreover, the studies of Nyau et al. (2013), Alqarni et al. (2016), and Kamal et al. (2019), support the current findings. Honey samples that have less or no TSS indicate that the honey was tampered with during processing.

TDS is used to quantify the organic and inorganic ionic components dissolved in honey (Salama et al., 2019). The tested honey samples had an average TDS of 415±77.13 ppm. These findings align with those of Salama et al. (2019), and Islam et al.(2012). In addition, Table 3 reveals that there is a strong correlation between TDS and EC, indicating that these metrics can be used to assess the quality and purity of honey (Moniruzzaman et al., 2014). This study showed a significant correlation between pH and TDS, which was previously mentioned by Horčinová et al. (2019). Also, FA and TDS were shown to be significantly correlated (Table 3); this relationship was supported by Rivera-Mondragón et al. (2023).

Regardless of its locality, honey is known as an acidic material. However, variations in acidity could be caused by seasonal harvesting or the plant’s provenance. According to various research, e.g., EI Sohaimy et al. (2015), there are many minerals in honey, which affect its pH. The average pH of the tested honey samples was 4.0±0.30. The pH values of every sample were consistent with Saudi and international standards and previous findings (e.g., El Sohaimy et al., 2015; Raweh et al., 2023). The pH of local Sidr honey (Ziziphus spp.) was similarly higher (<6.1) than the standard range (3.40 to 6.10), which is in line with prior studies that found high pH in sidr honey (Alqarni et al., 2016). The honey samples’ average EC was 0.6±0.11 mS/cm, which complies with both national and international quality standards. It is clear that high EC values for Talh honey (1.18±0.06 mS/cm) are more closely linked to the type of origin plant (Raweh, Ahmed, et al., 2022; Trisha et al., 2023). The pH and EC of the honey samples showed a positive correlation, which is consistent with the findings of Veleva et al. (2022) and (Ratiu et al. 2019). Moreover, the tested samples had a low FA with an average value of 36.6±5.79 meq/kg. Except for Acacia (A. gerrardii and A. ehrenbergiana) honeys, all assessed honey samples had free acidity values less than 50 meq/kg. (Codex, 2001; and GSO, 2014). These values were consistent with earlier research (Alqarni et al., 2016; Geană et al., 2020; Raweh et al., 2023) who showed no fermentation found in Talh honey samples that had high acidity values.

The amount of FA in Acacia honey was higher than allowed (≤50 meq/kg). The mean FA value in Acacia honey was so high because honey originates from Acacia spp. Trees have high FA due to the nature of the floral source (Veleva et al. (2022) and Raweh et al., 2023). Thus, Acacia honey has a characteristic of honey type, which is very relevant to its floral origin. Honey’s FA is the sum of all of its free acids (Lewoyehu and Amare, 2019). Organic acids are found in all honey types, particularly gluconic acid, which is the main acid present. Our investigation revealed significant and positive correlation between FA and EC (Table 3). As previously mentioned, the amount of FA in honey determines its EC value; the higher the FA, the higher the EC (Bogdanov et al., 2002 and Živkov-Baloš et al., 2018).

The HMF in reveals how recently honey was produced. Each honey sample’s HMF level varied significantly (p < 0.05) from the others (Table 2). The honey utilized in this investigation had an average HMF content of 15±3.74 mg/kg. According to numerous researches, raw or fresh honey does not contain HMF, and it can be affected by a number of variables, including temperature, heating time, and storage conditions. Moreover, too much heat and inappropriate storage conditions may cause the amount of HMF to increase (Alqarni et al., 2016; Khalil et al., 2010; Truzzi et al., 2014).

According to certain earlier studies, honey adulterated with inverted syrup may have a high HMF level. Since the HMF content shows the uniqueness and freshness of honey, it should be within the allowed limit, which is less than 80 mg/kg. A process known as inversion can convert sucrose into HMF when sugars are heated in the presence of acids (Trisha et al., 2023). In our findings, DN and HMF had a strong negative significant correlation (Table 3). This relation was also tested in previous studies (White, 1994 and Pasias et al., 2017).

Diastases are naturally occurring enzymes present in honey. The testing of the diastase level can reveal any heat exposure to of honey or adverse storage conditions, since overheating or exposure to high temperatures during storage would reduce the enzyme activity (Krishnasree and Ukkuru, 2017). According to Yardibi and Gumus (2010), honey with extremely low or high DN may be spoiled or acid-forming. The average DN for all tested honey samples was 13±1.60. All samples were within the Codex standard limits (≥8), indicating their freshness. These findings align with the findings of previous studies (e.g. Krishnasree and Ukkuru, 2017; Raweh et al., 2023; Trisha et al., 2023 and Abdi et al., 2024).

5. Conclusions

The analysis of physicochemical properties in twelve honey samples collected from various botanical sources in Saudi Arabia has been conducted. This study focused on numerous key parameters, including TDS, TSS, MC, pH value, FA, EC, (DN), and HMF. The results indicate that these honey samples generally meet both national and international quality standards, showcasing their freshness and low levels of any adulteration. Most of the evaluated parameters aligned with established quality benchmarks. However, it was noted that the free acidity level in Acacia honey surpassed some of these standards, likely due to the specific plant source. Numerous factors, including the type of floral source, beekeeping techniques, and environmental conditions, can be blamed for the variances in these metrics that have been found. This study highlights the critical role of physicochemical properties in assessing honey quality. Monitoring physicochemical parameters is essential for effective quality control, the development of appropriate certification benchmarks, and the production of high-quality honey in Saudi Arabia. Furthermore, these findings support the establishment of region-specific standards that account for the distinctive physicochemical characteristics of Saudi honey, thereby facilitating quality assurance, authenticity verification, and improved market recognition.