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European Journal of Applied Sciences – Vol. 9, No. 5
Publication Date: October 25, 2021
DOI:10.14738/aivp.95.10896. Valentin, A. A., Robert, N. B., & Sawaliho, B. E. H. (2021). DFT Investigation of Carbon Dioxide Effects with Temperature on Hydrated
Tetra and Penta-Saccharide Complexes. European Journal of Applied Sciences, 9(5). 142-161.
Services for Science and Education – United Kingdom
DFT Investigation of Carbon Dioxide Effects with Temperature on
Hydrated Tetra and Penta-Saccharide Complexes
Ablé Anoh Valentin
Laboratoire de Constitution et Réaction de la Matière
UFR SSMT, Université Félix Houphouët-Boigny
22 BP 582 Abidjan 22, Côte d’Ivoire
N’Guessan Boka Robert
Laboratoire de Constitution et Réaction de la Matière
UFR SSMT, Université Félix Houphouët-Boigny
22 BP 582 Abidjan 22, Côte d’Ivoire
Bamba El Hadji Sawaliho
Laboratoire de Constitution et Réaction de la Matière
UFR SSMT, Université Félix Houphouët-Boigny
22 BP 582 Abidjan 22, Côte d’Ivoire
ABSTRACT
Plantain banana mainly constitutes by water and starch. The latter includes
amylopectin and amylose. Glucose represents their core molecule. This work aims
to elucidate the temperature and carbon dioxide effects in four (AM4G) or five
(AM5G) of its hydrated synthons (basic unit). Ultimately, it wants to identify their
role in the deterioration of starch components. The research exploits the resources
of quantum chemistry to generate the relevant geometric, thermodynamic, and
spectroscopic parameters related to the hydrated tetra and penta-saccharide at the
ONIOM level (B3LYP/6–311++G [d, p]: AM1). Their analysis reveals the following
results. The temperature maintains the geometries of both complexes. It retains
most of the enthalpies, and entropy associated with their formation. Moreover, it
lowers the free enthalpies of the latter. Furthermore, it increases the frequency
shifts ∆��"�. This work also identifies the action of carbon dioxide. This one almost
conserves the geometry of the two complexes and their hydrogen bonds. Its effects
on the thermodynamic quantities depend on the temperature. Carbon dioxide
maintains the exothermic character of the complexations involved. More, it
transforms their entropy. It increases the free enthalpy of fluctuating importance.
It keeps the non-spontaneity of complexation reactions. Its effects concern the
frequency shifts ∆��"�. These rely on the temperature. Dioxide carbon exalts them
in function of these latter.
Keywords: temperature, carbon dioxide, amylose and ONIOM
INTRODUCTION
Plantain banana constitutes a source of energy and nutrients [1]. Côte d’Ivoire produces
1.7 million tonnes annually. It deploys various methods to conserve its performance. It
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Valentin, A. A., Robert, N. B., & Sawaliho, B. E. H. (2021). DFT Investigation of Carbon Dioxide Effects with Temperature on Hydrated Tetra and
Penta-Saccharide Complexes. European Journal of Applied Sciences, 9(5). 142-161.
URL: http://dx.doi.org/10.14738/aivp.95.10896
implements different cultivation techniques to improve its productivity. However, it struggles
to cover the needs of its inhabitants; post-harvest losses are quantified at nearly 30% of
production [2]. The theoretical chemistry team wants to suggest ways to increase the green life
of this fruit. Its researchers are trying to understand the degradation modalities of mass- produced foods. Subsequently, they recommend the properties of candidate molecules that
could reduce these huge losses. Before, it presents and discuss preceding work.
Starch represents the main constituent of green plantain. It consists of two polysaccharides,
amylose and amylopectin. These polymers comprise chains of α-D-glucose linked by osidic
bridges. Water hydrolyzes them into disaccharides or monosaccharides during ripening [3.4].
It establishes hydrogen bonds with the hydroxyls of D-glucose [5.6]. It contributes to its rapid
alteration. The team’s previous work sheds light on this mechanism. Temperature also acts role
in this process.
Its increase accelerates the maturing of the banana. Cold plays an important role in retarding
its metabolism [7], [8]. It prolongs the duration of the green state and maintains the quality of
the fruit [9, 10, 11]. Furthermore, carbon dioxide participates in the preservation process of
bananas in a controlled atmosphere [12.13]. Its enzymatic hydrolysis decreases if stored in an
environment with 10% CO2 [14]. But previous works reveal that water, temperature, and
carbon dioxide constitute three factors that can elucidate the degradation of green bananas.
They remain silent on the mechanisms shaping their effects. This research wants to fill this gap.
It targets to answer the following question:
What are the mechanisms underlying the effects of temperature and carbon dioxide on
green bananas?
This work aims to explain the role of temperature and carbon dioxide in starch degradation. It
generates and analyzes geometric, thermodynamic, and spectroscopic parameters using
quantum calculations on complexes of four (AM4G) and five (AM5G) amylose synthons. It
calculates and discusses them for the AM4G-H2O, AM4G-H2O-CO2, AM5G-H2O, and AM5G-H2O- CO2 complexes. It performs the calculations at 298 K and 286 K. The article includes four main
parts.
The first one follows this introduction. It describes the compounds and the method of study.
The second presents the results. The third comments on these. It explains the effects of
temperature and CO2 on geometric, thermodynamic, and spectroscopic parameters of the
complexes and hydrogen bonds (HB) related to the formation of these. A conclusion closes this
presentation in the fourth.
COMPOUNDS AND METHOD
This section deals with the procedures of the calculations. First, it presents the polysaccharides
under study and their geometrical, energetic, or spectroscopic parameters.
Compounds
Starch comprises two polysaccharides, amylose, and amylopectin. The first corresponds to a
linear polymer of D-glucose in α (1–4). The second is another from D-glucose (1–4). It has
branches in α (1–6) amylose. This study focuses on complexes of four or five D-glucose units
with water. They have three and four osidic bridges respectively. Figure 1 shows the 3D
molecular structure of AM4G (four synthons) and AM5G (five synthons). All oxygen are sp3
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European Journal of Applied Sciences (EJAS) Vol. 9, Issue 5, October-2021
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hybridized. The bridge is numbered from 1 to 3 for first polysaccharides and to 4 for the second
one. These numerals also correspond to the names of the different HB complexes. Quantum
Methods permit identifying them.
Method
All calculations perform using the ONIOM (Own N-layered Integrated Molecular Orbital)
method developed by Morokuma and all [15]. Our previous work utilizes it to highlight the HB
sites of amylose and amylopectin [16]. The ONIOM method suits here for this reason. It consists
of splitting any complex into two parts. Each part behaves at different levels of calculation
(figure 2).
For AM4G-H2O and AM5G-H2O, the water, and the carbons of the osidic bridge and their
hydrogen constitute the first (internal) part. This division makes it possible to describe the HB
precisely. The calculations carry out at a high level (B3LYP/6–311++G [d, p]). The diffuse and
polarization functions consider the isolated pairs of oxygen and their interactions with the
hydrogen in water. For the second (external) part, the semi-empirical AM1 approach helps to
capture the remainder of the complex environment in a less rigorous way.
AM4G AM5G
Fig. 1: 3D image of the AM4G and AM5G
Fig. 2: Calculation scheme according to the ONIOM method