Among the commercially cultivated Brassicaceae (Cruciferae) plants, Brassica juncea, Brassica napus, Brassica rapa, and Sinapis alba store significant amounts of oil and protein in the seed. At present, Brassica seed proteins are primarily used for livestock feeding based on the nutritional value. The point of curiosity is whether the present knowledge on the protein structure, biochemical characteristics, nutritive value, and the recovery processes are inadequate to develop Brassica proteins into a usable plant protein source or these proteins are of substandard for uses beyond animal nutrition applications. Cruciferin (11S) and napin (2S) are the predominant storage proteins of Brassicaceae seeds that contribute to different properties and functions. A gamut of information is available on the chemistry, nutritional value, as well as the functionality in foods, and associated non-protein components of canola/rapeseed storage proteins. The intention of this article is to critically review what is known about the predominant storage proteins of commercially produced Brassicaceae seeds relative to the above aspects and identify the knowledge gaps.

Proteins of Brassicaceae Oilseeds and their Potential as a Plant Protein Source

Rapeseed freeze-dried meal and water-soluble fraction were acylated with succinic and acetic anhydride and methylated with formaldehyde at different concentrations of these reagents, and changes in phytic acid, phenols, glucosinolate content, and functional properties were determined. In general, the greater was the extent of acetylation, the lesser was the extractability of phytic acid, phenols, and glucosinolates in both preparations. Water absorption and fat absorption capacities were enhanced by acetylation, but succinylated meal absorbed a maximum amount of oil at a minimum level of modification. Nitrogen solubility, foaming capacity, and viscosity were markedly improved by succinylation. Emulsifying properties were adversely affected by acylation, while methylation proved to be stimulatory. Modified water-soluble fractions had low content of antinutritional constituents, and acylated extracts showed better emulsifying and foaming properties. Keywords: Antinutritional factors; chemical modification; ...

Improvement of functional properties of rapeseed (Brassica campestris var. toria) preparations by chemical modification

Hydrothermal pretreatments for loosening the hull of Westar canola (Brassica napus L.) to promote dehulling of the seeds were investigated. The samples tested had on average 14.5% hull on a mass basis. Conditioning treatments involved soaking the seeds in distilled water or exposing the seeds to saturated steam. The moistened seed was treated with one of the following drying methods: unheated-air drying, infrared drying, and fluidized-bed drying. The dried grain was milled in an abrasive dehuller to break the hulls loose. The hulls were removed from the mix by aspiration. The treated seeds yielded a minimum of 11.4% to a maximum of 14.9% of the seed mass as the hull fraction. Nontreated seeds yielded 9.4% of the seed mass in hull fraction after abrasive dehulling and aspiration. Among treatments, raising the moisture content of the whole seed from 6 to 15% by exposure to steam, followed by drying in a fluidized bed, resulted in the maximum percent dehulling efficiency. The hull fraction contained about 24% crude fiber, 18% oil, and 18% protein on a dry-mass basis.

Dehulling of Canola by Hydrothermal Treatments

Production of Rapeseed Flour for Human Consumption1

The effect of supercritical carbon dioxide (SC-CO2) extraction conditions (temperature, pressure, extraction time, and moisture content of the samples) on the myrosinase activity and glucosinolate hydrolysis in flaked and whole canola seeds was studied. Combined effects of high temperature (75 °C), pressure (62.1 MPa), and moisture (∼20% w/w) were necessary to achieve 90% enzyme inactivation in canola flakes in 3 h. Similar extraction conditions resulted in only 44% enzyme inactivation in whole canola seeds. Significant glucosinolate degradation was observed after 5 h of extraction of low moisture content (8.5% w/w) whole canola seeds. Glucosinolate degradation in canola flakes was minimal at all moisture levels studied. Therefore, myrosinase inactivation prior to SC-CO2 extraction of canola flakes may not be necessary. However, the presence of enzyme activity in canola extracted at low moisture or temperature should be taken into account for further utilization of meal. Keywords: Supercritical CO2; myros...

Effect of Supercritical CO2 on Myrosinase Activity and Glucosinolate Degradation in Canola

The thioglucosides (which are precursors of toxic principles) and the fibrous hulls of rapeseed are the two major factors which limit the utilization of rapeseed meal as a protein supplement in human foods. In commercial practice the enzyme responsible for the liberation of toxic principles from thioglucosides is destroyed by a dry-heat treatment, but no attempt is made to remove the thioglucosides or the fibrous matter from the meal. The new wet-heat method of processing to inactivate myrosinase also results in the production of an improved quality of oil. In this paper the advantages of a wet-heat treatment in processing rapeseed are discussed.

New process for the production of better‐quality rapeseed oil and meal. I. Effect of heat treatments on enzyme destruction and color of rapeseed oil

Feasibility studies have shown that a white, bland, defatted, thioglucoside-free flour can be prepared from rapeseed. The thioglucosides, the precursors of toxic principles, present in rapeseeds are removed by aqueous extraction. The key operations, boiling of the seed followed by wet-grinding and aqueous extraction, help in the removal of seed coat from the rapeseed. Although aqueous extraction results in the loss of solids, the quality of the end products is good and may offset the loss.

N. W. Tape

Papers

New process for the production of better‐quality rapeseed oil and meal. I. Effect of heat treatments on enzyme destruction and color of rapeseed oil

New process for the production of better quality rapeseed oil and meal: II. Detoxification and dehulling of rapeseeds — feasibility study