During maturation, an areca nut goes through several transformations.
Transformation from the initial liquid stage to a patterned
hard nut consisting of W and B regions is associated with different
physical and chemical changes. To understand the structural
changes during maturation we have chosen to study areca nut at
six maturity stages; we discuss below in detail three significantly
different maturity stages, while some information on the other
stages is included in Supplementary material. We have analyzed
multiple samples, typically 3, at the same maturity stage for statistical
validity of our data, especially at the initial stages. Stage 1 is a
tender areca nut, stage 2 is a ripened nut, and stage 3 is a completely
matured nut without husk. Structural evolution in the nut
was studied by MRI. As MRI is a non-invasive technique and can
generate layer by layer images of the whole sample, it is best suited
for our purpose. Fig. 3 displays typical MR images at three different
stages of maturation. Supplementing this, the volume localized
NMR spectrum gives in situ information on the metabolite soup,
ie, mixture of various metabolites, at the molecular level, from
the chosen region within the sample, the region of interest being
selected with the help of the MR image. Fig. 4 shows typical