Evaluation of Chemical Compounds in Local Garlic Genotypes from Southwestern Romania

Abstract

Garlic (Allium sativum L.) is one of the most esteemed plants due to its medicinal properties. Its health benefits for humans are attributed to its chemical compounds. Few studies characterize garlic genotypes cultivated in Romania concerning their chemical composition. In this context, this study aimed to determine the chemical compounds for 16 local garlic genotypes cultivated under the same climatic and technological conditions. The chemical characteristics studied were the total phenolic content (TPC), total flavonoid content (TFC), reducing sugar content, antioxidant activity (AO), vitamin C, and acidity level. Chemical composition varied significantly among genotypes: TPC ranged from 656.07 to 1317.32 µg GAE/g FW; TFC ranged from 427.08 to 1447.90 µg QE/g FW; vitamin C ranged from 3.24 to 5.37 mg/g FW; reducing sugar content ranged from 3.24 to 5.37 mg/g FW; and the acidity level for the control was 6 meq/100 g. Among the selected genotypes, differences were observed between 3.48 and 11.02 meq/100 g. Significant correlations were noted between different compounds, specifically between TPC and AO, as well as between TPC and acidity level. In conclusion, this study highlights significant variability in terms of chemical composition of local garlic genotypes, which indicates notable differences between them and suggests that the genotypes may have different potential in medicinal and nutritional uses due to their distinctive chemical compositions.

1. Introduction

Garlic (Allium sativum L.) is one of the oldest horticultural species propagated vegetatively, dating back 5000 years [1,2]. It possesses a rich chemical composition of active substances: water (62–68%), fiber (1.5%), sulfur compounds (1.1–3.5%), carbohydrates (26–30%), proteins (1.5–2.1%), fatty acids, essential amino acids (1–1.5%), enzymes, vitamins (C, E, B1, B2, B6), and minerals (Mg, P, K, Ca, Se, Fe, Zn) [3,4,5]. The factors significantly influencing its chemical composition include genotype and environmental conditions, soil quality and fertility, precipitation, photoperiod, temperature, and agricultural practices [6,7]. Therefore, it is recommended that the choice of variety be made according to environmental requirements and quality standards imposed by the market [8]. The distinctive taste and health-improving properties of garlic are associated with sulfur compounds (33), such as allicin, alliin, and many other derivatives [9]. Allicin has 1% of the efficacy of penicillin [10]. Garlic comprises two groups of antioxidants: flavonoids and sulfur compounds [5]. Over time, it has been found that garlic possesses multiple biological properties, such as anticancer, antioxidant, antidiabetic, antibacterial, antifungal, and antihypertensive activities [11]. Research regarding garlic consumption has shown that it reduces oxidative stress and the risk of age-related diseases [12]. Due to these beneficial effects and its low toxicity, garlic represents a promising ingredient in the development of functional foods aimed at treating or preventing various conditions [13]. According to Lisciani et al. and Bonasia et al. [14,15], identifying and highlighting the chemical properties of local garlic genotypes, compared to commercial varieties, could represent an advantage for consumer preferences. Montano et al. [6] appreciate that these studies could enable breeders to develop stable varieties with higher or lower levels of biochemical compounds, depending on nutritional and/or technological needs. In this context, this study aimed to evaluate the chemical compounds in some local garlic genotypes from southwestern Romania. The evaluation of chemical compounds in local garlic genotypes is a relatively new field of research, with multiple innovative and relevant considerations for the scientific community and for practice, such as the identification of genotypes that have not been previously analyzed or documented, or the identification of the specific effects of the growing conditions in the environment of southwestern Romania on chemical composition. Investigating the specific biological activities of local genotypes can highlight local garlic as a valuable resource for pharmaceuticals and dietary supplements. Initiatives made to identify, characterize, and conserve local genotypes are essential for preserving biodiversity and for securing genetic resources for the future.

2. Materials and Methods

2.1. Materials

For this study, 16 garlic genotypes were selected, including 15 local genotypes (G1–G15) identified in the Oltenia region of Romania and one commercial variety, ‘Benone’. All garlic genotypes were cultivated under the same environmental conditions and agricultural practices in an experimental plot located in the northern part of Craiova city (44°21′55″ N/23°48′18″ E).

2.2. Determination of Vitamin C Content

The ascorbic acid content was determined using the iodometric method. Extraction from the biological material was performed in 2% hydrochloric acid (HCl) (1:30 g/v) and filtered. Ascorbic acid was then titrated with 4 mM potassium iodate (KIO₃) in the presence of 1% potassium iodide (KI). The resulting iodine (I₂) reacts with ascorbic acid, oxidizing it to dehydroascorbic acid. The endpoint of the redox titration was determined by the first excess of iodine, which forms a deep blue-violet complex with starch. The results are expressed as mg/100 g fresh weight (FW).

2.3. Determination of Reducing Sugars

Reducing sugars (%) were extracted in distilled water (1:20 g/v) for 60 min at a temperature of 60 °C and tested colorimetrically at 540 nm with 3,5-dinitrosalicylic acid using glucose as the standard (5 mg/mL).

2.4. Determination of Acidity

Acidity was determined from the aqueous extract used for the determination of reducing sugars, by titration with 0.1 N NaOH in the presence of phenolphthalein as an indicator. The results are expressed in meq/100 g.

2.5. Determination of Total Phenolic Compunds

The free phenolic compounds present in the selected samples were extracted with 80% methanol (1:10) in an ultrasonic bath (Fungilab, Barcelona, Spain) at 24 °C for one hour. The resulting mixture was centrifuged for 5 min at 4000 rpm, and the supernatant was collected. Total phenolic content (TPC) was determined colorimetrically at 765 nm using the Folin–Ciocalteu method. Gallic acid was used to generate the standard curve, and the results are expressed as μg gallic acid/g FW.

2.6. Determination of Total Flavonoid Content

Total flavonoid content (TFC) was determined using a colorimetric method with 10% aluminum nitrate and 5% sodium nitrite in an alkaline medium. Absorbance was read at 500 nm, and the results were calculated from the quercetin calibration curve. The results are expressed as μg quercetin equivalents per gram (μg QE/g FW).

2.7. Determination of Antioxidant Capacity Using the DPPH Radical

Antioxidant activity was determined by the ability of the extracts to reduce the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical. A 0.075 M ethanolic solution of DPPH radical was mixed with the sample extract. The absorbance of the mixture was monitored at 517 nm for 20 min at 2-min intervals. A control sample of 0.075 M ethanolic DPPH solution was used to monitor the stability of this solution over time.

The percentage of DPPH radical neutralization was calculated using the following formula:

% antioxidant = [A0 − (A1 − As) × 100/A0

(1)

where:

A0 = absorbance of the DPPH solution

A1 = absorbance of the mixture (DPPH solution + sample extract)

As = absorbance of the sample extract.

This neutralization percentage was compared to that achieved by the standard solution Trolox, which is used as an antioxidant standard. The results of antioxidant capacity are expressed as μmol Trolox Equivalents (TE) per gram of fresh weight (μM TE/g FW).

For all spectrophotometric determinations, a Thermo Evolution 600 spectrophotometer with Vision Pro software 9.9 SR1 was used.

2.8. Chemicals and Reagents

Folin–Ciocalteu reagent (2 N), hydrochloric acid (37%), potassium iodate, 6-hydroxy-2,5,7,8-tetramethylchroman2-carboxylic acid (Trolox), and methanol were purchased from Merck (Darmstadt, Germany). Gallic acid (99% purity), anhydrous sodium carbonate (99% purity), anhydrous sodium acetate (98% purity), aluminum nitrate (99% purity), sodium nitrite (99% purity), 3,5-Dinitrosalicylic Acid (98% purity), quercetin, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH, 90% purity) were procured from Sigma-Aldrich (Darmstadt, Germany).

2.9. Statistical Analysis

All determinations were performed in triplicate. The results are expressed as means ± standard deviation. Statistical analysis was performed using IBM SPSS Statistics 26 software. Prior to conducting a one-way ANOVA, the homogeneity of variances was tested using Levene’s test. Data normality was assessed using the Shapiro–Wilk test. A one-way ANOVA was used to determine the significance of differences among groups. Post-hoc comparisons were made using Duncan’s multiple range test at a significance level of p < 0.05 to identify which specific groups differed.

3. Results

3.1. Total Polyphenol Content (TPC)

TPC was measured using the spectrophotometric method with the Folin–Ciocalteu reagent from fresh garlic samples and varied between 656.07 µg GAE/g FW (G8) and 1317.32 µg GAE/g FW (G3), while ‘Benone’ had a value of 671.98 µg GAE/g FW. The obtained values for the total polyphenol content exceeded the control in 14 of the analyzed genotypes, with statistically significant differences among them (

Table 1. Analysis of the variability of chemical compounds in garlic genotypes.

Genotype	TPC (µg GAE/g FW)	TFC (µg QE/g FW)	Ascorbic Acid (mg/g FW)	AO (µM TE/g FW)	Reducing Sugars (%)	Acidity (meq/100 g)
‘Benone’	671.98 ± 27.15 g	572.81 ± 36.85 h	3.76 ± 0.26 de	0.74 ± 0.08 gh	1.16 ± 0.09 ef	6.00 ± 0.86 fg
G1	947.28 ± 21.78 cd	427.08 ± 50.76 i	3.99 ± 0.09 d	1.11 ± 0.07 cde	1.07 ± 0.06 g	4.28 ± 0.43 hi
G2	925.42 ± 30.66 cde	1248.00 ± 123.18 b	3.52 ± 0.04 f	0.58 ± 0.12 h	1.21 ± 0.05 e	9.28 ± 0.32 c
G3	1317.32 ± 128.53 a	960.41 ± 51.94 cd	3.86 ± 0.12 d	1.75 ± 0.12 a	1.17 ± 0.05 ef	10.50 ± 0.58 ab
G4	976.43 ± 12.72 c	735.41 ± 42.85 fg	4.80 ± 0.19 b	1.51 ± 0.04 ab	1.47 ± 0.06 ab	6.66 ± 0.45 ef
G5	938.38 ± 15.85 cde	631.00 ± 25.97 gh	5.37 ± 0.08 a	0.97 ± 0.06 efg	1.55 ± 0.05 a	9.56 ± 0.47 bc
G6	904.37 ± 15.83 cde	1447.90 ± 276.35 a	3.99 ± 0.13 d	1.43 ± 0.13 b	1.48 ± 0.04 ab	5.40 ± 0.71 g
G7	959.43 ± 17.61 c	757.78 ± 45.17 fg	3.91 ± 0.03 d	1.44 ± 0.19 b	1.10 ± 0.06 fg	6.80 ± 0.54 ef
G8	656.07 ± 37.43 g	631.25 ± 31.76 gh	3.96 ± 0.11 d	0.68 ± 0.28 h	1.32 ± 0.06 cd	3.48 ± 0.82 i
G9	1110.85 ± 114.64 b	1022.91 ± 45.51 c	4.22 ± 0.21 c	1.46 ± 0.18 b	1.33 ± 0.05 cd	9.44 ± 0.73 bc
G10	807.20 ± 15.78 ef	827.08 ± 49.80 def	3.52 ± 0.11 f	1.30 ± 0.20 bcd	1.32 ± 0.03 cd	5.32 ± 0.73 gh
G11	816.11 ± 15.49 def	956.25 ± 36.63 cd	3.24 ± 0.09 g	0.82 ± 0.14 fgh	1.40 ± 0.02 bc	6.94 ± 0.67 ef
G12	886.50 ± 26.39 cde	812.18 ± 41.93 ef	3.52 ± 0.11 f	1.36 ± 0.13 bc	1.30 ± 0.02 d	7.68 ± 0.52 de
G13	1094.33 ± 165.45 b	961.78 ± 52.71 cd	3.88 ± 0.09 d	1.39 ± 0.17 bc	1.41 ± 0.03 bc	11.02 ± 0.54 a
G14	1111.87 ± 117.61 b	977.68 ± 48.32 cd	3.61 ± 0.03 ef	1.72 ± 0.22 b	1.49 ± 0.01 ab	8.56 ± 0.67 cd
G15	758.84 ± 49.02 fg	708.35 ± 19.70 fgh	4.22 ± 0.08 c	1.04 ± 0.09 def	1.45 ± 0.04 b	5.26 ± 0.61 gh

Mean ± Standard Deviation; Different letters indicate statistically significant differences (Duncan multiple range test, p < 0.05); TPC—total polyphenol content; TFC—total flavonoid content; AO—antioxidant activity.

).

3.2. Total Flavonoid Content (TFC)

Data on the total flavonoid content (TFC) in fresh garlic samples also show significant variations, ranging from 427.08 µg QE/g FW (G1) to 1447.90 µg QE/g FW (G6). Similar to the total polyphenol content, 14 out of 15 genotypes exceeded the control value (572.81 µg QE/g FW), indicating a high flavonoid content in the majority of the analyzed genotypes. The significant differences between genotypes underscore their importance in determining flavonoid content (Table 1).

3.3. Vitamin C

Upon analyzing the vitamin C content of the garlic genotypes under study, it was observed that the obtained values are below those reported by other authors. In this study, the values for the 16 analyzed genotypes range between 3.24 mg/g FW (G11) and 5.37 mg/g FW (G5), with the control ‘Benone’ having a value of 3.75 mg/g FW. Among the 15 genotypes, 10 reported values exceeded the control (Table 1).

3.4. Antioxidant Acivity

The antioxidant activity of the 16 analyzed garlic genotypes ranged from 0.58 µM TE/g FW (G2) to 1.75 µM TE/g FW (G3), with the control ‘Benone’ having a value of 0.74 µM TE/g FW. Among the 16 genotypes, 13 exhibited higher antioxidant activity than the control. The significant differences between genotypes underscore the importance of genotype selection in achieving high antioxidant activity values (Table 1).

3.5. Reducing Sugars

These findings indicate a significant variation in the content of reducing carbohydrates among different garlic genotypes, reflecting the genetic diversity of the species. The higher values of reducing carbohydrates in most genotypes compared to the control suggest the potential of these genotypes to provide additional nutritional benefits. Further research is needed to better understand the variation in reducing carbohydrate content and its impact on the quality and nutritional value of garlic. These research results highlighted significant variations in the content of reducing carbohydrates among the analyzed garlic genotypes. The highest content of reducing carbohydrates (1.55%) was recorded within genotype G5, while the lowest content was recorded in genotype G1 (1.07%). In comparison, the ‘Benone’ variety recorded an intermediate content of 1.16%. Thus, the majority of genotypes (13 out of 16) exhibited higher levels of reducing carbohydrates than the control (Table 1).

3.6. Acidity

The results obtained in the research regarding the acidity level in the analyzed garlic genotypes present significant variations. The acidity value for the control was 6 meq/100 g. Significant differences were observed among the selected genotypes: genotype G8 exhibited the lowest acidity value (3.48 meq/100 g), while genotype G13 had the highest acidity, a value of 11.02 meq/100 g. Additionally, 10 genotypes were noted to have acidity values higher than that of the control (Table 1).

Correlation analysis aids in evaluating the relationship between chemical compounds in the bulb of the studied genotypes (

Table 2. Pearson correlation matrix between biological compounds of garlic genotypes.

	Reducing Sugars	Ascorbic Acid	TPC	TFC	AO	Acidity
Reducing sugars	1	0.356 *	−0.014	0.267	0.138	0.123
Ascorbic acid	0.356 *	1	0.126	−0.283	0.070	0.106
TPC	−0.014	0.126	1	0.319 *	0.667 **	0.689 **
TFC	0.267	−0.283	0.319 *	1	0.229	0.349 *
AO	0.138	0.070	0.667 **	0.229	1	0.294 *
Acidity	0.123	0.106	0.689 **	0.349 *	0.294 *	1

* Correlation is significant at the 0.05 level (2-tailed); ** Correlation is significant at the 0.01 level (2-tailed).

). Correlation coefficients between the chemical characteristics of garlic genotypes (reducing carbohydrates, ascorbic acid, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (AO), and acidity) are presented in Table 2. These analyses revealed significant positive correlations between AO and TPC (r = 0.667 **), as well as between acidity level and TPC (r = 0.689 **).

This indicates that a higher polyphenol content influences the antioxidant capacities of garlic, as well as higher acidity levels. These results align with other authors who have also reported a positive relationship between total polyphenol content and antioxidant activity [3,16,17,18,19]. According to findings presented by Čeryová et al. [18], it is noteworthy that the relationship between total polyphenol and flavonoid content and antioxidant activity significantly depends on the plant species, specific polyphenols and flavonoids present, and the conditions under which the plant was cultivated. Moderately significant correlations were found between ascorbic acid and reducing carbohydrates (r = 0.356 *), between TPC and TFC (r = 0.319 *), between TFC and acidity (r = 0.349 *), as well as between AO and acidity (r = 0.249 *). Bhandari et al. [20] also reported a positive relationship between total polyphenol and total flavonoid content.

In Figure 1, the relationship between total phenolic content (TPC) and antioxidant activity (AO) is illustrated. The trend line, resulting from a regression analysis, indicates the general direction of the relationship between the two variables (y = 0.0016x − 0.2756). There is a positive correlation between total phenolic content and antioxidant activity in the analyzed dataset (R² = 0.5638). In other words, as the phenolic content increases, an increase in antioxidant activity is expected, and vice versa.

4. Discussion

Phenolic compounds are important constituents that influence the quality, taste, color, and nutritional properties of plants [21]. The results obtained regarding the chemical compound content in garlic genotypes showed significant differences between the studied genotypes and the analyzed parameters, thus indicating a high degree of genetic diversity, and this is crucial for plant breeding programs as it allows the selection and development of new varieties with established characteristics such as disease resistance, adaptability to different environmental conditions, and higher yield.

Data related to the total polyphenol content (TPC) measured in fresh garlic samples from various studies show significant variations, highlighting the impacts of genotype, environment, and agricultural practices on these values: between 367.11 and 472.11 mg GAE/kg FW, which are lower than the range reported in the current study [18]; between 430.26 and 640.04 mg GAE/kg FW, also lower than those in the current study [17]; between 92.20 and 119.60 mg GAE/100 g FW, similar to the higher values in the current study [19]; between 21.27 and 33.96 mg GAE/g DW, significantly higher than those reported in the current study and other analyzed studies [16]; 780 mg GAE/kg FW [22]; similar to the values in the current study were the values reported between 212.86 mg and 487.23 GAE/ g [23]. Compared to other studies, the polyphenol content values were per gram of fresh garlic (FW), revealing a wide range of variation depending on the genotype. This specific reporting approach is essential in making direct and relevant comparisons between different studies and in assessing genetic and environmental impacts on garlic polyphenol content. Different garlic genotypes exhibit significant differences in polyphenol content, as observed in the current study, where 14 genotypes exceeded the control values.

TFC values vary significantly among the analyzed studies, similar to the total polyphenol content, influenced by genotype, environmental conditions, and measurement methods: between 10.00 and 21.90 mg CE/g DW, values significantly higher than those in this study [20]; between 10.30 and 60.49 mg CE/kg FW, lower than in the present study [17]; between 7.49 and 11.24 mg CE/kg FW, reported values lower compared to those in this study [18]; similar to the values in the current study were the values reported between 223.50 and 1609.94 µg QE/g [23]. These variations reflect the complexity and diversity of factors that influence the chemical composition of garlic. Significant differences in TFC values between studies reflect the genetic diversity of garlic. Each genotype has a different capacity to synthesize and accumulate flavonoids, which is influenced by its genetic characteristics. Factors such as soil type, climate, exposure to sunlight, and agricultural practices can significantly influence the content of flavonoids, and they can modify the biochemical processes in plants, thus affecting the synthesis and accumulation of flavonoids. Flavonoids, due to their antioxidant and anti-inflammatory properties, play an important role in human health, and studies made on their diversity in garlic genotypes can guide the selection and cultivation of varieties with superior nutritional benefits. This fact underscores the importance of continued research in this area to maximize the beneficial potential of garlic.

To contextualize the values for vitamin C, additional information is provided from the literature. Vitamin C is implicated in various physiological processes, including the stimulation of the immune system, collagen synthesis, hormone synthesis, and iron absorption [24]. Increasing the vitamin C content of plants can have beneficial effects on human health, such as improving human health, antioxidant properties, and improving the immune function, respectively [25]. Vitamin C values ranged between 0.097 and 0.155 mg/g FW in the study conducted by Gambelli et al. [7], significantly lower than those in this study. Values ranging from 0.268 to 0.658 mg/g FW, also much lower than the values in this study, were reported in the study conducted by Fratianni et al. [26]. In another study that analysed the content of vitamin C, reported values were around 10.46 mg/100 g and 13.63 mg/100 [23]. Considerably lower values compared to those in this study were reported by Bonasia et al. [15], values between <0.001 and 0.03 mg/g FW. Identification and quantification of antioxidant content represent a crucial step in investigating the total antioxidant properties relating to the potential health benefits of foods [27]. According to Atif et al. [28], the antioxidant properties of garlic are influenced by environmental conditions. Thus, longer photoperiods and higher temperatures affect the nutritional characteristics of garlic, leading to higher quantities of phenolic substances, proteins, and sugars, thereby enhancing antioxidant capacity. This confirms the assertion that light can significantly improve the antioxidant activity of polysaccharides [29]. To contextualize these results, the following values of antioxidant activity from the specialized literature are presented: between 0.932 and 1.906 mg/g FW suggest that the values in this study are comparable, albeit slightly lower [19]; values as 0.664 and 1.036 μmol TE/g were reported in another study [23]; values ranging from 0.63 to 1.46 mmol TE/kg FW fall within the range of this study, indicating methodological similarities [17]; values between 0.51 and 1.05 mmol TE/kg FW are also within the range of this study, confirming methodological consistency [18]. Antioxidant activity varies significantly among genotypes studied in different regions, reflecting the influence of genetic and environmental factors.

Carbohydrates play a significant biological role, and some carbohydrates can act as reducing agents [30]. All monosaccharides are reducing carbohydrates, along with some disaccharides, oligosaccharides, and polysaccharides [31]. This finding indicates a significant variation in the reducing carbohydrate content between different garlic genotypes, with the reducing sugar content ranging from 3.24 to 5.37 mg/g fresh weight (FW), thus reflecting the genetic diversity of the species, a fact supported by other studies, too [14]. The higher values of reducing carbohydrates in most genotypes compared to the control suggest the potential of these genotypes to provide additional nutritional benefits. The carbohydrates in garlic not only provide energy, but they also play an essential role in maintaining digestive health. In addition, the carbohydrates in garlic are involved in creating the specific aroma and taste of this food, which makes it a valuable ingredient in various culinary preparations. In addition to their nutritional and culinary role, the carbohydrates in garlic support various functional health benefits. They can help regulate blood sugar levels, thus providing a beneficial effect on glucose metabolism. Also, certain carbohydrates in garlic have antioxidant properties, which help protect cells from oxidative stress and may reduce the risk of chronic disease. Therefore, further research is needed to better understand the variation in reducing carbohydrate content and its impact on the quality and nutritional value of garlic.

Regarding the level of acidity, the significant variations in acidity levels (3.48 and 11.02 meq/100 g) among garlic genotypes reflect the genetic diversity of the species and possible differences in their metabolism. These variations indicate that different garlic genotypes may metabolize and accumulate organic acids in different ways, which may be influenced by genetic, environmental, and growing conditions. In comparison, another study by Rasul Suleria et al. [12] reported an average acidity of 0.49%, thus highlighting the significant variability of this parameter, depending on the source and type of garlic studied. The acidity level of garlic is an important factor contributing to its chemical diversity and varied uses in the food and medicinal fields, influencing the shelf life of garlic and the sensory properties or bioavailability and efficacy of certain bioactive compounds in garlic. Local genotypes of garlic are valuable in terms of biological diversity [32,33] and can offer, in terms of chemical composition, varied benefits for medicinal and nutritional uses, due to the significant variability of their bioactive compounds. This genetic diversity is reflected in significant differences in terms of the content of vitamins, minerals, antioxidants and other bioactive substances, thus making local genotypes an important resource for research and development.

5. Conclusions

It is concluded that the genotypes studied have managed to stand out with high values of chemical compounds, often surpassing the values recorded by the ‘Benone’ variety used as a control. This indicates that these genotypes have greater potential regarding the concentration and/or diversity of chemical compounds, which could provide them with advantages in various fields, such as in nutrition or medical research. These research directions not only explore new aspects of local garlic genotypes, but they also provide valuable insights for practical applications in agriculture, medicine, and food. This contributes to innovation and sustainable development. Future research will focus on expanding the analysis to include advanced spectroscopy techniques for comprehensive structural characterization of compounds and exploring their synergistic interactions. Additionally, we will investigate the complex interactions between different environmental conditions and genotypes, including the use of predictive modelling to anticipate changes in chemical composition under varying climate conditions.