2.1. Obtaining starch from hard and soft jackfruit seeds
Jackfruit seeds (A. heterophyllus L.) (soft and hard) were extracted
from mature fruits purchased from a local market in João
Pessoa city, Paraíba State, Brazil. The brown spermoderm covering
the cotyledons was removed by immersing jackfruit seeds in a 5%
sodium hydroxide solution, followed by washing with running
water. The starch was extracted from the cotyledons.
The extraction of starch from hard and soft jackfruit seeds was
conducted according to the slightly modified methodology of Loos,
Hood, and Graham (1981). First, seeds were removed from pulp,
peeled, cut into small pieces and allowed to soak for 24 h in a sodium
metabisulphite solution (0.2%). Starch was extracted by
grinding the raw material with sodium metabisulphite in a regular
blender at low speed for 30 min. After homogenisation, the mix-
ture was processed through a 200 mesh sieve (0.074 mm).
The samples were then decanted twice for 24 h, with resuspen-
sion in sodium metabisulphite and centrifugation at 5000 rpm/
15 min between each decanting; the supernatants of both were
discarded. The white starch residue was spread on a tray and dried
in lyophiliser – Terroni Equipmentos LTDA (LS 3000, São Paulo,
Brazil) at a temperature of 45 C. The dried starch was sprayed
and stored in a plastic container under refrigeration until use.
2.2. Chemical quality of seeds and starch from hard and soft jackfruit
seeds
The chemical composition of seeds and starch from hard and
soft jackfruit seeds was determined according to the methodology
described in the AOAC (2012). Analyses of moisture were conducted
by desiccation in an oven at 105 C until a constant weight
was achieved; total lipids by extraction with hexane in Soxhlet;
ash by incineration in a muffle furnace at 550 C; total protein by
the Kjeldahl method (N 6.25); and starch by acid hydrolysis followed
by quantification by titration using Fehling reagents A and B.