PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF FLOUR OBTAINED FROM THE BULB OF Lilium brownii

Abstract

Chemical, physical and functional properties of flour obtained from the bulb of Lilium brownii were studied. Results obtained from analyses using AOAC and phenol-sulphuric acid methods show that lily flour has low protein (13.7%) but high carbohydrate contents (58.7%), respectively. Blanching had minimal effect on biochemical components investigated. However, there was a significant difference in the colour of flour obtained from bulblets that were blanched and those that were not blanched as the former had a more acceptable colour than the latter. This is indicative of the fact that blanching minimized the occurrence of Maillard reaction. The amino acid composition as determined using Amino Acid Analyzer show that lily flour lacks two of the sulphur amino acids (cystine and cysteine), and contains low lysine (0.77 g/100 g sample) and methionine (0.10 g/100 g sample) contents. Arginine, a basic amino acid that is nutritionally considered as an essential dietary requirement for children but not for adults, is present in a relatively large quantity (2.99 g/100 g sample). Blanching slightly affected the amino acid contents as those samples that were blanched had comparatively lower amino acid contents. Differences in protein composition between defatted sesame flour and lily flour resulted in differences in water and fat absorption capacities as the latter exhibited a lower water and fat absorption capacities than the former. Similarly, whipping properties were influenced by differences in protein contents because sesame flour with higher protein content exhibited superior whipping properties over lily flour.

Analysis of neutral sugar components by Gas Chromatography revealed that lily flour contains predominantly glucose (48.4%) with very low xylose and arabinose contents. Molecular weight distribution was determined using high performance liquid chromatography and results show that lily flour has a molecular weight distribution ranging from 2.91 × 10²6. Flour from lily bulb exhibited favourable functional properties such as ability to absorb water and fat, emulsification, foaming and whipping which could be usefully employed in some food preparations.

Key Words: Lily, functional properties, Maillard reaction.

AJFAND Vol.4(2) 2004