Phytosterols In Oil Research Articles

Phytosterol Depletion in Soybean Oil Using a Synthetic Silica Adsorbent

Phytosterols in vegetable oils have gained attention for their nutritional benefits in foods and food supplements. However, the use of vegetable oils in emulsions for infant formulas and parenteral nutrition has raised some concerns, as phytosterols may contribute to phytosterolemia in the case of infant formulas and, in a second scenario, to parenteral nutrition-associated liver disease. The present study proposes removing phytosterols from soybean oil using a synthetic amorphous silica Trisyl® (E551) as an adsorbent material. The process is simple and involves stirring the oil at a high temperature under vacuum conditions followed by filtration to remove the adsorbent. A rotational factorial design of experiments, considering the adsorbent/oil ratio, temperature, and time was carried out to determine the optimal conditions. Additionally, the effects on tocopherols levels and formation of trans fatty acids were explored. The total sterol content in the initial refined soybean oil was 2540 mg/kg, with 32% in ester form (813 mg/kg). The treatments effectively reduced the sterol concentration, achieving a reduction of nearly 70% when 10% Trisyl®, 140 °C, and a 90-min treatment were applied. Under these conditions, nearly 80% of the oil was recovered. Campesterol and stigmasterol levels were almost halved. Tocopherol losses were found to be below 20%. Thermal degradation, as analyzed by triacylglycerol polymers and trans fatty acids, was not observed in the treatments.

In Situ Rapid Analysis of Squalene, Tocopherols, and Sterols in Walnut Oils Based on Supercritical Fluid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry.

Quantification of liposoluble micronutrients in large-scale vegetable oil samples is urgently needed, because their health benefits are increasingly emphasized. However, current analytical methods are limited to either labor-intensive preparation processes or time-consuming chromatography separation. In this work, an online oil matrix separation strategy for direct, rapid, and simultaneous determination of squalene, tocopherols, and phytosterols in walnut oil (WO) was developed on the basis of the lipid class separation mode of supercritical fluid chromatography. A single run was completed in 13 min containing 6 min of column cleaning and balancing. Satisfactory limit of detections (0.05-0.20 ng/mL), limit of quantifications (0.15-0.45 ng/mL), recoveries (70.61-101.44%), and matrix effects (78.43-91.62%) were achieved, indicating the reliability of this method. In addition, eight sterol esters were identified in WO, which have not previously been reported. The proposed method was applied to characterize the liposoluble micronutrient profile of WO samples obtained from different walnut cultivars, geographical origins, and processes.

Two Argan Oil Phytosterols, Schottenol and Spinasterol, Attenuate Oxidative Stress and Restore LPS-Dysregulated Peroxisomal Functions in Acox1-/- and Wild-Type BV-2 Microglial Cells.

Oxidative stress and inflammation are the key players in neuroinflammation, in which microglia dysfunction plays a central role. Previous studies suggest that argan oil attenuates oxidative stress, inflammation, and peroxisome dysfunction in mouse brains. In this study, we explored the effects of two major argan oil (AO) phytosterols, Schottenol (Schot) and Spinasterol (Spina), on oxidative stress, inflammation, and peroxisomal dysfunction in two murine microglial BV-2 cell lines, wild-ype (Wt) and Acyl-CoA oxidase 1 (Acox1)-deficient cells challenged with LPS treatment. Herein, we used an MTT test to reveal no cytotoxicity for both phytosterols with concentrations up to 5 µM. In the LPS-activated microglial cells, cotreatment with each of these phytosterols caused a significant decrease in intracellular ROS production and the NO level released in the culture medium. Additionally, Schot and Spina were able to attenuate the LPS-dependent strong induction of Il-1β and Tnf-α mRNA levels, as well as the iNos gene and protein expression in both Wt and Acox1-/- microglial cells. On the other hand, LPS treatment impacted both the peroxisomal antioxidant capacity and the fatty acid oxidation pathway. However, both Schot and Spina treatments enhanced ACOX1 activity in the Wt BV-2 cells and normalized the catalase activity in both Wt and Acox1-/- microglial cells. These data suggest that Schot and Spina can protect cells from oxidative stress and inflammation and their harmful consequences for peroxisomal functions and the homeostasis of microglial cells. Collectively, our work provides a compelling argument for the protective mechanisms of two major argan oil phytosterols against LPS-induced brain neuroinflammation.

Influence of the Extraction Method on the Quality and Chemical Composition of Walnut (Juglans regia L.) Oil.

The present study investigated and compared the quality and chemical composition of Moroccan walnut (Juglans regia L.) oil. This study used three extraction techniques: cold pressing (CP), soxhlet extraction (SE), and ultrasonic extraction (UE). The findings showed that soxhlet extraction gave a significantly higher oil yield compared to the other techniques used in this work (65.10% with p < 0.05), while cold pressing and ultrasonic extraction gave similar yields: 54.51% and 56.66%, respectively (p > 0.05). Chemical composition analysis was carried out by GC−MS and allowed 11 compounds to be identified, of which the major compound was linoleic acid (C18:2), with a similar percentage (between 57.08% and 57.84%) for the three extractions (p > 0.05). Regarding the carotenoid pigment, the extraction technique significantly affected its content (p < 0.05) with values between 10.11 mg/kg and 14.83 mg/kg. The chlorophyll pigment presented a similar content in both oils extracted by SE and UE (p > 0.05), 0.20 mg/kg and 0.16 mg/kg, respectively, while the lowest content was recorded in the cold-pressed oil with 0.13 mg/kg. Moreover, the analysis of phytosterols in walnut oil revealed significantly different contents (p < 0.05) for the three extraction techniques (between 1168.55 mg/kg and 1306.03 mg/kg). In addition, the analyses of tocopherol composition revealed that γ-tocopherol represented the main tocopherol isomer in all studied oils and the CP technique provided the highest content of total tocopherol with 857.65 mg/kg, followed by SE and UE with contents of 454.97 mg/kg and 146.31 mg/kg, respectively, which were significantly different (p < 0.05). This study presents essential information for producers of nutritional oils and, in particular, walnut oil; this information helps to select the appropriate method to produce walnut oil with the targeted quality properties and chemical compositions for the desired purpose. It also helps to form a scientific basis for further research on this plant in order to provide a vision for the possibility of exploiting these oils in the pharmaceutical, cosmetic, and food fields.

Genotype and Environment Effects on Phytosterol and Tocopherol Contents in Almond Kernel Oil

The phytosterol and tocopherol contents of almond kernel oil were evaluated in three almond cultivars, including the Spanish cultivar ‘Marcona’ and the French cultivars ‘Ferragnès’ and ‘Ferraduel’, grown under two different agro-climatic conditions, Zaragoza (Spain) and Meknès (Morocco). The analysis of variance showed significant effects of the genotype on kernel phytosterol content, Δ5-Avenasterol, Δ7-Campesterol, Stigmasterol and on the three tocopherol isomers. The location effect was significant on oil and kernel phytosterol contents, β-sitosterol,Δ5-avenasterol, Δ7-stigmastenol, Δ7-campesterol and α- and γ-tocopherol. The highest value of kernel and oil phytosterol contents were observed at Meknès (1.48 g kg−1 and 2.54 g kg−1, respectively), as compared to those obtained at Zaragoza (1.31 g kg−1 and 2.54 g kg−1, respectively).The highest values ofβ-sitosterol and Δ5-avenasterol were obtained at the Zaragoza location (81.93% and 10.55% of total phytosterols, respectively).The highest value of α-tocopherol was observed in the Morocco location (496 mg kg−1 oil). These results indicate that under warm climate conditions in Morocco, the almond cultivars tend to accumulate more phytosterol and tocopherol. However, the significance of the genotype × location interaction on the phytosterol and tocopherol contentindicates that the magnitude of variation in these traits mainly depends on the genotype.

Analysis of Changes in the Amount of Phytosterols after the Bleaching Process of Hemp Oils.

Unrefined vegetable oils from niche oilseeds are now sought after by consumers because of their unique nutritional properties and taste qualities. The color and flavor intensity of niche oils is a big problem, and their refining is not industrially feasible due to the small production scale. The study undertaken aimed analyze the effect of changing the amount of phytosterols (PSs) after the bleaching process of hemp oils of the 'Finola', 'Earlina 8FC' and 'Secuieni Jubileu' varieties. Cold-pressed (C) and hot-pressed (H) crude vegetable oils were bleached with selected bleaching earth (BE) at two concentrations. The post-process BE was extracted with methanol. The amount of PSs in the crude oils and the extract after washing the BE with methanol was analyzed by GC (gas chromatography). The study shows that the bleaching process did not significantly affect the depletion of PSs in the oils. Trace amounts of PSs remain on the BE and, due to methanol extraction, can be extracted from the oil. The conclusion of the performed research is that the bleaching of hemp oil does not cause depletion of the oil, and it significantly improves organoleptic properties. The oil bleaching process results in an oil loss of less than 2% by weight of the bleached oil, while the loss depends on the type of BE used. The study shows that the loss of phytosterols after the bleaching process averages 2.69 ± 0.69%, and depends on the type of BE used and the oil extracted from different varieties of hemp seeds.

Simultaneous determination of squalene, tocopherols and phytosterols in edible vegetable oil by SPE combined with saponification and GC-MS

A method for simultaneous determination of 14 functional components of squalene, tocopherols and phytosterols in edible oil was established based on solid phase extraction (SPE), saponification and gas chromatography-mass spectrometry (GC-MS). Depending on the characteristic ions of the target substances, 14 compounds were well separated in 20 min. The limit of detections (LOD) and the limit of quantifications (LOQ) were in the range of 0.010–0.050 and 0.033–0.167 μg/mL, respectively. Method validation showed linearity of calibration curves (α = 0.05) with the recoveries at three spiked levels between 91.29 and 111.93%. The relative standard deviation (RSD) of intra-day and inter-day precisions were less than 6.11%. The results derived from the established method demonstrated a wide variation of detected compounds in 15 kinds of common edible vegetable oils. The proposed SPE combined with saponification and GC-MS provides a rapid and simple method for the simultaneous determination of the functional compounds in oils and detection of the adulterated vegetable oil.

Comparison of chemical characterization and oxidative stability of Lycium barbarum seed oils: A comprehensive study based on processing methods

Five different processing methods (cold pressing, hot pressing, solvent extraction, ultrasound-assisted solvent extraction, and supercritical fluid extraction) were evaluated to extract oils from Lycium barbarum (L. barbarum) seeds based on the lipid composition, minor bioactive components, and oxidative stability of oils. A large proportion of unsaturated fatty acids was detected in the L. barbarum seed oil, especially linoleic acid (65.24-66.26%). Minor bioactive components were abundant in L. barbarum seed oils, including tocopherols (292.65-488.49mg/kg), phytosterols (9606.31-166,684.77mg/kg), polyphenols (35.65-113.87mg/kg), and carotenoid (4.17-46.16mg/100g). Specifically, the phytosterol content was higher than that of other common oils. Comparing the different processing techniques, ultrasound-assisted solvent extraction provided the highest extraction yield and recovery. The quantities of tocopherols, phenols, and phytosterols in hot-pressed oil were higher than those in oils extracted from other methods, and thus it had the best oxidative stability. L. barbarum seed oils extracted by different techniques showed various characteristics and could be distinguished through principal component analysis and hierarchical cluster analysis. PRACTICAL APPLICATION: L. barbarum seed oil is a potentially underutilized oil resource with abundant essential fatty acid and phytosterol, which owns great value to apply in the nutritional, cosmetic, and medicinal fields. Hot pressing is an efficient method to produce L. barbarum seed oil for health care with high nutritional value and good quality, which can also be easily implemented on an industrial scale.

Water-In-Oil Pickering Emulsions Stabilized by Microcrystalline Phytosterols in Oil: Fabrication Mechanism and Application as a Salt Release System

Recently, Pickering emulsions stabilized by edible particles have attracted significant attention from the scientific community and food industry owing to their surfactant-free character. However, those edible particles are mostly used for stabilizing oil-in-water emulsions, whereas those for water-in-oil emulsions are very limited. In this article, stable water-in-oil Pickering emulsions were prepared through dispersing phytosterol particles in oil phase, and the effects of antisolvent treatment, the type of oil, particle concentration, and water fraction on the stability, type, and morphology of these emulsions were investigated. In addition, the release profile of salt as a model aqueous compound from these emulsions has also been studied. Results showed that due to its higher water content, the antisolvent pretreatment of phytosterol in the ethanol/water system facilitated the dispersion of dried phytosterol particles into oil phase as microcrystals. Water-in-oil Pickering emulsions with droplet sizes of 80-100 μm were fabricated at phytosterol concentrations of 1.5-3% w/v and water fractions of 0.2-0.6. The dissolved phytosterol molecules in oil phase could help in emulsion stabilization through interfacial crystallization during emulsification, evidenced by polar microscopic observations. Moreover, the salt release from phytosterol-stabilized Pickering emulsions showed a temperature-dependent profile which could have potential application in a controlled-release system. The current study provided important information for fabrication of stable water-in-oil emulsion using natural particles.

Investigation into the bioavailability of synthesized phytosterol esters in vitro and in vivo using Caco-2 cell model and Wistar rats

Phytosterols are bioactive components capable of reducing the level of cholesterol in serum. In this study, phytosterol acetic ester (PA), phytosterol oleate ester (PO) and phytosterol linoleic ester (PL) were synthesized from phytosterol (PS) and organic acid to improve the solubility of phytosterols in oil. The purities of PA, PO and PL were 98.4, 95.9 and 95.7%, respectively. Caco-2 cell monolayers and Wistar rats were used to research the bioavailability of synthesized esters (PE) in vitro and in vivo. Experiments using the Caco-2 cell monolayer model showed that the transport mechanism of phytosterol esters was passive transport. Experiments in vivo showed that the PS content in rat blood reached the highest level at 3 h, with a value of 21.82 μg/mL. PS content in the liver was the highest at 3 h, with a value of 43.65 μg/g. Bioavailability of PL is the highest, reaching a value as high as 19.57%. Acute study in the rats showed that the PS concentration in blood was at the safe level, and it had no side effects for health. In conclusion, the bioavailability of PL and PO is better than PS, PL and PO have more advantages in application.

GC/EI-MS method for the determination of phytosterols in vegetable oils

Sterols are a highly complex group of lipophilic compounds present in the unsaponifiable matter of virtually all living organisms. In this study, we developed a novel gas chromatography with mass spectrometry selected ion monitoring (GC/MS-SIM) method for the comprehensive analysis of sterols after saponification and silylation. A new referencing system was introduced by means of a series of saturated fatty acid pyrrolidides (FAPs) as internal standards. Linked with retention time locking (RTL), the resulting FAP retention indices (RIFAP) of the sterols could be determined with high precision. The GC/MS-SIM method was based on the parallel measurement of 17 SIM ions in four time windows. This set included eight molecular ions and seven diagnostic fragment ions of silylated sterols as well as two abundant ions of FAPs. Altogether, twenty molecular ions of C27- to C31-sterols with 0–3 double bonds were included in the final method. Screening of four common vegetable oils (sunflower oil, hemp oil, rapeseed oil, and corn oil) enabled the detection of 30 different sterols and triterpenes most of which could be identified.Graphical abstract

Effect of agitation and added cholesterol esterase on bioaccessibility of phytosterols in a standardized in vitro digestion model

There is great interest in reaching a consensus method for in vitro digestion of foods. The COST INFOGEST network of researchers has developed a standardized protocol, which is appropriate for basic digestibility studies, but may be insufficient for more complex studies, such as micronutrient bioaccessibility. In the present study, the bioaccessibility of phytosterols (PS) was evaluated using the standardized and modified versions of the in vitro digestion protocol. The INFOGEST protocol was used without modification for 2% solutions of either free phytosterols (FPS) or esterified phytosterols (EPS) in soybean oil. The effect of two variables which have yet to be explored using the INFOGEST protocol was subsequently evaluated. Those variables are: (1) changing the mode of agitation from orbital shaking to head over heels (HOH) rotation and (2) adding pancreatic cholesterol esterase (CE) during the intestinal phase. Bioaccessibility of FPS was greater than that of EPS, and HOH rotation caused a further increase in bioaccessibility of FPS but not EPS. Addition of CE caused a slight, but significant improvement in bioaccessibility of EPS, though hydrolysis was incomplete. Our findings highlight a need for further evaluation of the standardized in vitro digestion protocol, especially for complex studies such as lipid bioaccessibility.

Phytosterols in edible oil: Distribution, analysis and variation during processing

Phytosterols, which are naturally occurring in plants, have excellent nutritional and health values on lowering both the blood cholesterol level and the risk of cardiovascular diseases. Edible oils are the main source of daily intake of phytosterols, whereas the properties of phytosterols may vary a lot depending on their sources. During the processing of edible oil including refining and frying, phytosterol's content fluctuates, which influences the properties of the final product. Phytosterols and their derivatives undergo physical migration between different phases and chemical conversion during the processing, which reduces the quality and the commercial value of edible oils. Therein, the loss of phytosterols is the major concern in the process of neutralization and deodorization. In addition, oxidation and thermal degradation of phytosterols occur simultaneously during frying, which also reduces the content of phytosterols. Nevertheless, the oil matrix has a promoting or an inhibitory effect on the thermal oxidation of phytosterols. Therefore, various efforts have been devoted to analyzing and improving the remaining contents of phytosterols in edible oil. Regardless of the processing method, temperature plays an important role in the loss of phytosterols. At present, the main analysis methods of phytosterols include gas chromatography and liquid chromatography, in which the pretreatment of different types of phytosterols is also a crucial step. This review focused on the following topics comprehensively: (i) the distribution of phytosterols in the oil-containing plants and edible oils during the refining processing; (ii) the pretreatment and analysis methods of various phytosterols (free phytosterols, phytosteryl fatty acid esters, phytosteryl glycosides and acylated phytosteryl glycosides); (iii) the variation of phytosterols in process of esterification and oxidation, storage and so on. The study also proposed that the investigation in the loss and safety of phytosterols during processing of the vegetable oils should be proceeded further in combination with efficient and accurate chromatography methods.

Thermo-Oxidation of Phytosterol Molecules in Rapeseed Oil during Heating: The Impact of Unsaturation Level of the Oil.

Phytosterols are naturally occurring substances in foods of plant origin that have positive effects on the human body. Their consumption can reduce the level of low density lipoprotein (LDL) cholesterol. The presence of unsaturated bonds in their structure leads to their oxidation during production, storage, and thermal processes. The aim of the study was to determine how the degree of unsaturation of rapeseed oil affects the oxidation of phytosterols in oil during 48 h of heating. In all not-heated oils, the dominant groups of oxyphytosterols were 7α- and 7β-hydroxy sterols. During 48 h of heating, the rapid decrease of phytosterols’ levels and the increase of the content of oxyphytosterols were observed. The main dominant group in heated samples was hydroxy and epoxy sterols. Despite differences in fatty acid composition and content and composition of single phytosterols in unheated oils samples, the total content of oxyphytosterols after finishing of heating was on a similar level for each of the tested oils. This showed that the fatty acid composition of oil is not the only factor that affects the oxidation of phytosterols in foods during heating.

Determination of Phytosterols in vegetable oils by GC-MS method

In this study, a method for determination of six phytosterols by gas chromatography-mass spectrometry with derivatization in vegetable oils was validated. The samples were hydrolyzed in an alkaline media at 70&amp;deg;C for 60 min. Then, the samples were performed liquid-liquid extraction with toluene. The phytosterols are derivatized to trimethylsilyl ethers and then analyzed by gas chromatography-mass spectrometry. The limit of detection and limit of quantification was 5 and 15 mg/kg, respectively. Recoveries of six phytosterols were between 93.5% and 101%.

Olive mill wastewater polyphenol‐based extract as a vegetable oil shelf life extending additive

Olive mill wastewater (OMW) was used as a source to extract radical scavenging compounds, in order to study their possible valorization as natural antioxidants. Their antioxidant activity (IC50 0.32 µg/ml) was found to be more potent than that of a commercial antioxidant: Ascorbic acid (AA) (IC50 1.91 µg/ml). The olive mill wastewater extract (OMWE) and AA were separately added to two vegetable oils, sunflower oil and rapeseed oil. These oils were then put under simulated storage conditions (accelerated test at 60°C) for 4 weeks. The physicochemical parameters, analysis of fatty acids, phytosterols, and tocopherols were the key parameters used to monitor the evolution of the oxidation state. The results obtained showed that the oils treated with the OMWE underwent oxidative deterioration slower than that of the control (without additives), and that phytosterols and tocopherols content decreased as a function of storage time following first-order kinetics. The use of the OMWE helped reduce the loss of both phytosterols and tocopherols in 4 weeks by half compared to the control samples, with the exception of total phytosterols in rapeseed oil where the loss reduction was not as important (about 2% loss reduction). Practical application Antioxidants are widely used in the food industry, as they prevent the development of rancid aromas that lead to harmful consequences during storage and cooking. The practical implication of the study is that natural radical scavenging compounds extracted from OMW can be efficiently used to enhance the quality and safety of refined oils stored at high temperature conditions.

Effect of cold-pressed on fatty acid profile, bioactive compounds and oil oxidation of hazelnut during oxidation process

The aim of this paper was to explore the regulation of oxidative characteristics (peroxide value, p-anisidine value, conjugated diene value, total oxidation value), fatty acids and main bioactive compounds (tocopherols, squalene, carotenoids and phytosterols) in cold-pressed hazelnut oil (CHO) during accelerated oxidation for 40 days. Additionally, radical formation and molecular structure were monitored by electron spin resonance (ESR) and Raman spectroscopy, which evaluated the radical intensity and structure evolution of carotenoids and fatty acids, respectively. Tocopherols and carotenoids decreased until they could not be detected, and squalene decreased slightly, whereas phytosterols had not significantly change. Hazelnut oil entered a stage of high oxidation after 30 days by principal components analysis (PCA) with 22 measured variables. These results provide a better understanding of relationships between bioactive compositions and oxidation characteristics, which will provide a reference for choosing natural antioxidants to increase the shelf-life.

Phytosterols Content in Vegetable Oils of Brazil: Coconut, Safflower, Linseed and Evening Primrose

Abstract In the last years phytosterols, natural components of plants, have received more attention due to association of their consumption with reducing risk of cardiovascular diseases and cancer. There are several scientific studies about phytosterols in vegetable oils, but they are scarce in unconventional oils. The objective of this research was evaluating the content of phytosterols (β-sitosterol, stigmasterol and campesterol) in vegetable oils sold in Sao Paulo city, in Brazil. The analysis included cold alkaline saponification, derivatization with hexamethyldisilazane and trimethylchlorosilane reagents, and quantification by gas chromatography using flame ionization detection and internal standardization. The quality control parameters indicated that the method was suitable for analysis. Total sterols were between 272.3 mg kg-1 (coconut oil) to 6169.7 mg kg-1 (evening primrose oil). β-sitosterol was the component found in higher concentrations and evening primrose oil was the most representative in quantity of phytosterols.

Simultaneous Determination of Free Phytosterols and Tocopherols in Vegetable Oils by an Improved SPE–GC–FID Method

In this work, a simple and rapid SPE–GC–FID method for simultaneous determination of free tocopherols and phytosterols in vegetable oils was developed. The use of this SPE approach for the extraction of naturally occurring tocopherols and phytosterols provides advantages such as simplicity, high speed, and ease of use. The whole method was validated, and the limits of detection of tocopherols and phytosterols were 0.05 and 0.03 mg/100 g of oil, respectively. The precisions for the determination of tocopherols and phytosterols in vegetable oils were < 10.1% in relative standard deviations. The recoveries of selected tocopherols and phytosterols spiked at low, middle, and high concentrations ranged from 83.4 to 97.7%. The developed approach was successfully applied to the analysis of free tocopherols and phytosterols in rapeseed, sunflower seed, linseed, sesame, and maize oils.

Oil Phytosterol Concentration in Sunflower Presents a Dilution Response with Oil Weight per Grain

AbstractPhytosterols are plant sterols that present several benefits for human health. In crop species, such as sunflower, oil phytosterol concentration shows genetic and environmental variations. The reasons that cause such varied concentration of phytosterols in the oil are unknown. The aim of this work was to investigate the relationships between phytosterol concentration and composition and grain oil content in sunflower. Two sets of samples, with lines and hybrids grown in different environments in Argentina and Spain, were used to establish and validate the relationships between phytosterols and grain oil content. Oil phytosterol concentration decreased in both types of genotypes, lines, and hybrids, when oil content per grain increased. A dilution‐like relationship accounted for 82% of the variability in phytosterol concentration among genotypes and environments. Phytosterol concentration rapidly increased with oil contents lower than 11.4 mg per grain. This relationship was observed for total phytosterols and each type of the phytosterols analyzed. With low oil per grain, phytosterol composition varied, with higher proportions of β‐sitosterol and Δ7‐stigmastenol. The relationships established in this work could serve to design breeding and crop management strategies.