Investigation of the phytochemical composition of the seeds from four Huanglongbing (HLB) tolerant citrus genotypes and their potential as a biodiesel feedstock

Authors: ACHARYA, TEJ - Orise Fellow; Jeffries, Kristen; Bowman, Kim; Moser, Bryan; Moser, Jill; Dorado, Christina

Submitted to: Food Chemistry Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2025
Publication Date: 4/11/2025
Citation: Acharya, T., Jeffries, K.A., Bowman, K.D., Moser, B.R., Moser, J.K., Dorado, C. 2025. Investigation of the phytochemical composition of the seeds from four Huanglongbing (HLB) tolerant citrus genotypes and their potential as a biodiesel feedstock. Food Chemistry Advances. https://doi.org/10.1007/s12649-025-03049-x.
DOI: https://doi.org/10.1007/s12649-025-03049-x

Interpretive Summary: Citrus production in Florida has decreased by 90 percent due to Huanglongbing (HLB), also known as citrus greening disease. There is no effective method to control HLB. However, there are some citrus hybrid cultivars that exhibit tolerance to HLB and can be grown with little to no additional inputs for disease control. While these varieties may not replace commercial sweet orange for fresh consumption or juice due to their undesired flavor, they could be incorporated into the established infrastructure and used exclusively as a feedstock for value-added products from peel, pulp residue and seed. In this study, we focused on identifying value-added products from the seed of an HLB tolerant citrus genotype (HLB-TCG). The phytochemical composition of the seeds from four HLB-TCG, which were harvested at the fully developed mature green stages, was determined. Additionally, we identified 20 different amino acids in seeds, with high concentrations of phenylalanine, arginine, and asparagine. We also determined the bio-diesel properties from one of the four HLB-TCG seed (Sour Orange). Our investigation found that HLB-TCG seeds are rich in secondary metabolites that benefit human health such as limonoids, flavonoids, and polymethoxylated flavones. And can also be used for bio-diesel production. The results of this study provider growers and processors with knowledge on potential HLB-TCG that can be grown along with commercial varieties to increase revenue in an HLB endemic environment.

Technical Abstract: Citrus seeds are rich in protein, oil, carbohydrates, and bioactive compounds and contain significantly less water than peel and pulp, rendering them prime candidates for value-added product development. This study focused on characterizing the phytochemical composition of the seeds from four huanglongbing-tolerant citrus genotypes (HLB-TCG). Due to their value in biomedical applications, limonoids, flavonoids, coumarins, phenolic acids, amino acids and stilbenoids were measured in HLB-TCG seeds using LC-MS/MS. The HLB-TCG seeds were particularly rich in limonoids, and had high concentrations of individual flavonoids, such as naringin, narirutin, and hesperidin. The ‘Sunki’ seeds were rich in polymethoxylated flavones, especially tangeretin and nobiletin. Furthermore, all common amino acids were present, with phenylalanine, arginine, and asparagine being particularly abundant. Additionally, based on the ratio of total polyunsaturated fatty acids (FA) to total saturated and monounsaturated FA, as well as cloud point, pour point, and viscosity index, we conclude that there is potential for utilizing these seeds for biodiesel production. Moreover, higher concentrations of natural antioxidants like phytosterols and tocopherols suggest better performance of biodiesel due to protection against oxidation. Together, this data suggests the potential utilization of HLB-TCG seeds for value-added applications, such as isolation of bioactive compounds and biodiesel production.