Lipophilic compounds from maize fiber and rice husk residues – An abundant and inexpensive source of valuable phytochemicals

Abstract

Maize (Zea mays L.) fibers and rice (Oryza sativa L.) husks are abundant and low cost by-products generated during grain milling. In this work, the composition of the lipophilic compounds present in these materials, which accounted for 4.1 % in maize fibers and 2.2 % in rice husks, was thoroughly studied by GC–MS. The most abundant lipophilic compounds identified in these residues were n-fatty acids and acylglycerols (mono-, di-, and triglycerides), that altogether accounts for up to 88 % of all extractives in maize fibers and up to 95 % in rice husks. Steroid compounds, including free and esterified sterols, hydrocarbons, and ketones were identified in both samples, being present in significant amounts in maize fibers. Tocopherols were also present in both cereal by-products, albeit in lower amounts, with α-tocopherol being the most abundant one. Minor amounts of n-fatty alcohols and high molecular esters were also found in rice husks. Maize fibers and rice husks can, therefore, be potential feedstocks to obtain valuable phytochemicals of diverse industrial interest.