(414b) Ivory Nut (Phytelephas equatorialis) Residues: Chemical Composition for Applications in Health Care, Industry and Environmental Remediation - Towards Sustainabilty

Tagua or ivory nut is the hard endosperm of Phytelephas equatorialis, an Ecuadorian endemic specie that grows wild in the tropical coast of Ecuador at 1500 msnm. This palm completes its development after 15 years and produces uninterruptedly seeds afterward the twelfth or fifteenth year of life [1]. The genera Phytelephas belongs to the phytelephantoid palms [2], commonly only the seeds are recollected by hand from the ground, by the native people of the zone, who care and managed tagua palm environment, being their employee source [3]. In Ecuador, tagua seeds has had an important economy role, becoming one of the five most exported forest non-timber materials in the 20th century [4] . Its main use was the production of buttons from the textile industry, jewelry and handicrafts, before the World War II the industrial and technology development reduce de consume of ivory nut buttons [5][1]. Locally, people still manage and use tagua seeds for buttons industry [6], handicrafts [7]. Currently, new uses have been found for this seed, which has provided a different approach, the commercialization of ground tagua in different granulometries, one of the main uses of this material is the replacement of synthetic polymers in the health care, cosmeceutical and nutraceutic industries. [8]. In 2017, tagua exports were approximately $6.5 million (USD), with the main exporters being small and medium-sized companies [9]. These activities generate residues that are not currently part of the value chain, for instance tagua residues that do not reach an exportation quality – tagua slices are used as charcoal, and tagua powder as cattle feed [10]. In the grinding process, a powder of a particle smaller than 105 μm (higher than 150 mesh) remains as a co-product that do not have a specific use to commercialize, so it is necessary to develop a technology that allows their revalorization to develop high value-added products. This investigation studies the Ivory nut chemical composition, characteristics of their components and their application in the market. The main component of ivory nut is mannan (90%), that is a polysaccharide present in the cell wall [11].

Samples of ground ivory nut were studied following a modified version of ASTM Standard Test Method for Preparation of Extractive-Free Wood, then proximal analysis was performed, the analysis indicates 0,762% for nitrogen and 4,75% for protein, for lipids is 0,46% before extractive free pre-treatment and 0,35% for nitrogen and 2,19 % for protein, for lipids is 0,137 % after extractive free pre-treatment.

Hydrothermal pretreatment is considered an ecofriendly process avoiding corrosion problems and acid recycling, this process works at higher temperatures and pressures, to transform hemicelluloses into oligosaccharides, which can be used in food industry or applied to produce high- value chemicals [12], [13]. Samples were treated at various times and temperatures in a batch reactor, at a temperature of 170 °C for 30 minutes. Alkali dilute treatment is necessary to break down the rigid structure of the biomass, liberating the hemicelluloses for achieving high efficiency [12]. The treatment was NaOH 2% for 2 hours, then the liquid phase was mixed with ethanol to precipitate the hemicellulose, in this case mannan biopolymer.

FTIR analyses show peaks that demonstrate the presence of crystalline mannan/mannose, these points being around 3505, 3479 and 3375 cm ^-1 as Hori mentions in his research [14]. In this case the compared samples shows that the use of different pretreatment helps to increase the peaks. X ray diffraction analysis was performed to investigate the crystalline structure in ivory nut powder samples, results showed the presence of mannan/mannose over 16, 18, 20, 24, 25, and 29 angle, already determined as mannan I biopolymer by Alvarez et al. [15].

These are compounds of worldwide interest due to their industrial applications. The pharmaceutical industry has great projections for mannose as essential glyconutrient that prevents the risk of urinary tract infections. In addition, it is observed that it decreases the appetite and reduces the absorption of cholesterol [16]. This is a substitute for antibiotics since it acts as a type of lectin bond, which is believed to prevent the adherence of intestinal pathogens such as E. coli and certain species of salmonella in the intestinal mucosa [16], [17]. In the food industry, mannose is appreciated as a very noble type of sugar so it can be an alternative to sucrose for its flavor. Another alternative, since one of the characteristics of mannan biopolymer is that it can be used as a suspending and anti-caking agent in the case of powdered milk, mayonnaise, and dressing in addition to its use in confectionery production [17]. Mano-oligosaccharides (MOS) are produced from the degradation of mannan biopolymer and have been studied to boost the immunity of animals, MOS act as prebiotics and increase the conditions of the intestinal microflora, which promotes the health of broilers, ass dietary fiber decreases the incidence of disorders in the intestine. Mannan biopolymers are also known to stimulate the immune system and improve the performance of laying hens [18]. Lately, a novel application for tagua shell as adsorbent material for the removal of Pb II ions is being investigated [19]. Thus, residual tagua components would have potential use as health care industry, in cosmeceutics and nutraceutics, and in environmental remediation of heavy metals.

REFERENCES

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[2] A. S. Barfod, “The Rise and Fall of Vegetable Ivory,” no. January 1989, 1989.

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[19] G. A. Chávez-Prado et al., “Novel Application of Tagua Shell (Phytelephas aequatorialis) as Adsorbent Material for the Removal of Pb(II) Ions: Kinetics, Equilibrium, and Thermodynamics of the Process,” Sustain., vol. 14, no. 3, 2022, doi: 10.3390/su14031309.