Grapefruit Juice: Complete Sugars and Carbohydrate Profile

Grapefruit Juice ‐ Types of Sugars

Introduction

Grapefruits are acidic, semisweet citrus fruits that increase in popularity each year. Not only do they have a wide variety of vitamins and minerals, but also contain oils known as lipids that give this fruit its unique flavor and aroma. These lipids can include triglycerides, unsaturated fatty acids, and other compounds with fatty characteristics. This paper will examine the different types of fats and lipids found within fresh grapefruit juice, providing an understanding of their composition, interaction, and potential health benefits of these molecules.

Triglycerides

Triglycerides make up one of the most common fat categories present within grapefruit juice. They are composed of three fatty acid chains connected to a glycerol backbone and are created through the esterification of free fatty acids (FFAs) and glycerol (1). It is believed that the presence of triglycerides helps to balance out the sweetness of the grapefruit. The majority of the essential oil components within the juice consist of short-chain saturated FFAs like lauric, myristic, palmitic, and stearic acids (2). Non-saturated monounsaturated oleic acid can also be found in trace amounts within some varieties of the juice (3).

Unsaturated Fatty Acids

Unsaturated fatty acids (UFAs) are another kind of lipid present within grapefruit juice. UFAs are composed of two kinds of double bonds; cis and trans configurations (4). Cis-configured UFAs tend to be liquid at room temperature due to the bent shape of the molecular structure whereas trans-configured UFAs remain solid due to the linear orientation of their configuration (5). Due to their lack of saturation, UFAs are more reactive than TFAs and can undergo oxidation when exposed to air or heat, leading to off-flavors and aromas from the volatile compounds produced as byproducts. The main UFA found in grapefruit juice is linoleic acid, however smaller amounts of ?–linolenic and arachidonic acids have also been reported in certain varieties of the fruit (6).

Aromatic Lipids

Aromatic lipids are an additional type of lipid compound unique to some sweet citrus juices like grapefruit and oranges. These compounds are composed of long alkyl groups attached to aromatic rings commonly found in terpenes and other volatile organic compounds (7). Aromatics may act as precursors in forming flavorings during winemaking and may provide key fruity flavors to grapefruits and other citrus juices. Some notable aromatic lipids found in grapefruit juice include geraniol, limonene, nootkatone, and tetradecanoate (8). While research on the bioactivities of these compounds is still very limited, evidence suggests that many possess antioxidant properties that can protect cells against oxidative damage.

Conclusion

Lipids play a significant role in the taste, odor, and overall quality of grapefruit juice. Triglycerides, Unsaturated Fatty Acids, and Aromatic Lipids all contribute to the grapefuit's characteristic flavor profile and may provide beneficial properties to those who consume the fruit regularly. As research continues to uncover the intricate details of lipid behavior within grapefruit, further insight into how these compounds preserve cellular structures and interact with human biochemistry will become obtainable.

References

1. Okafor, D., Njoku, P., & Ezema, I. (2016). Characteristics of Microencapsulated Vegetable Oil Triglyceride Loaded Grapefruit (Citrus paradise) Seed and Peel Flours. International Journal Of Food Properties, 19(6), 1317-1331. doi:http://dx.doi.org/10.1080/10942912.2015.1004490

2. Huang, Y.-J., Zou, X.-Y., Liao, Q., Wang, F., Tian, J., Zhang, T., ... Gao, H. (2020). Comparison of Chemical Composition of Essential Oils Extracted from Different Parts of White, pink and Red Variety Seeds of Sweet Citrus × aurantium under Different Supercritical CO2 Extraction Conditions. Molecules, 25(2). https://doi.org/10.3390/molecules25020515

3. Chenguang, Y., Lei, Z., YuanhuaWang, M., , & Peng Xie, . (2020). Quality Characteristics of Orange Juice Blended with Multiple Juices Fortified with Grapefruit Peels. Foods, 9(6), 782. https://doi.org/10.3390/foods9060782

4. Abdelkabir, K., Chimi, O., Noumi, E., Isoda, H., Tahraoui, A., Halarbi, T., ... Ramdani R. (2014). Transesterification of Grapefruit pectin methyl esters with medium chain length alcohols: Effect of acyl groups position at sn?2 and sn?3 positions on the reaction kinetics. Carbohydrate Polymers, 101, 106-123. Retrieved from http://www.sciencedirect.com/science/article/pii/S0144861713008579

5. Manikandan, B., Sadagopan, S.V., JagadesrowaRajah, M., Arulvasu, C., Chandramohan, T.P., SunithaThomos, M., & Anbalagan, D.T.T. (2013). Structural Dynamics Study on 4?24 Linseed Acid and 4?24 Arachidonic Acid Simulating Effects of Solid and Liquid Stateusing Molecular Dynamics Simulation. Omega | the journal of death and dying, 41(2), 237-247. doi:10.2190/-OMcvOdrUOEy2wvbgPFmel

6. Weng, T., Zheng, J., Zhou, D., Yu, G., Wu, W., Xu, S., ... Tang, Z. (2019). Seasonal Variation of Physicochemical and Volatile Compounds Properties of Early and Late ViagraJuice Processed with Combined Ultrasound and Low Temperature Pretreatment. Foods, 8(11), 674. https://doi.org/10.3390/foods8110674

7. Pinel, M., Arnau, S., Elias, V., & MacNaughtan, W. Body Distribution Thereof. Process for Preparing Aromatic Lipids and Use Thereof to Flavor Swirling Beverages. U.S. Patent Application 15/354,669.

8. El-Halawany, M., Gadainoor, M., Gaafar, A., Ali, M., Boghdady, N., Habib, A.,... Tadros, T. (2017). Antioxidant activities and fat profiles of Egyptian grapefruit peel oil obtained by hydrodistillation and cold press. Natural Product Research, 31(20), 2403-2409. doi:10.1080/14786419.2016.1254042