TITLE:
Steeping of Whole Dried Maize Seeds in Buffers Altered Fatty Acid Ionization State, Composition, and Lipase Activity
AUTHORS:
Raphael Lartey Abban, Justice Kwabena Sarfo
KEYWORDS:
Lipase Activity, ‘Obatanpa’ Maize Variety, Oil Fraction, Steeping Media pH
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.8 No.11,
November
15,
2017
ABSTRACT:
Steeping is a simple model of studying the activation and modulation of the
physiological pathways involved in seed germination. In this study, steeping
of grains of the ‘obatanpa’ maize variety in buffers at different pH was monitored
through the measurements of lipase activity, oil yield, fatty acid component
and unsaturation, and germination capacity. Lipase activity of grains
steeped for four days decreased in the order: pH 3 > pH 5 > pH 7 > pH 9 > pH
11. Decreasing lipase activity was corroborated with decreasing free fatty acid
components, protein concentrations and oil yields. The unsaturation components
of the oil fractions only marginally increased with increasing steeping
media pH. Three major components were detected by TLC in all oil
fractions. The unique components were confirmed by their uniform
UV-absorption spectra converging at an isosbestic point of 290 nm. Germination
capacity was much reduced for seeds steeped in buffered media for 24
hours compared with seeds steeped in portable water though the pattern of
germination, which was monitored for five days, did not change. This study
has demonstrated the use of pH changes of steeping medium to modulate
physicochemical properties and germination of seeds. The physicochemical
changes were observed after seeds have been submerged under steeping buffer
for four days. Practical application: With proliferation of specialty maize
hybrids, the study provides an insight into the development of experimental
protocols for the selection of types of maize grain for preparation of foods and
beverages in terms of general characterization and lipolytic activity, which
have implications for flavor, taste and odor of the final products. The imminence
of this in some traditional ways of preparing malted and fermented maize
foods and beverages, which go through days of steeping, cannot be overemphasized.
This study therefore provides another dimension to the manipulation of
the steeping stage to develop varieties of maize-based product.