Preparation of Rapeseed Protein Isolate by Sodium Hexametaphosphate Extraction, Ultrafiltration, Diafiltration, and Ion‐Exchange

Abstract

A novel processing scheme for the production of rapeseed protein isolate was developed which includes extraction using aqueous sodium hexametaphosphate solution followed by activated-carbon treatment, ultrafiltration, diafiltration, and purification by ion-exchange. Aqueous sodium hexametaphosphate is an effective extraction agent for rapeseed proteins. The activated-carbon treatment removes glucosinolate hydrolysis products and color compounds. The membrane treatments reduce the concentration of soluble low-molecular-weight components to low levels. An anion exchange resin was used in the last step to remove phytate and residual hexametaphosphate. The process resulted in a protein isolate containing about 90% protein. Sixty-three per cent of the nitrogen in the meal was recovered as an isolate free of glucosinolates, low in phytates and fiber, light in color, and bland in taste.

Removal of phenolic compounds in the production of high-quality canola protein isolates

“…Although some other reagents such as sodium hexametaphosphate (SHMP) and NaCI were tested for rapeseed/canola protein extraction from the meal (Thompson et al, 1976;Tzeng et al, 1988a; Bhatty et al, 1968;Lo and Hill, 197 1; Finnigan and Lewis, l985), many reports indicated that high pH (>I 1 ) considerably increased the protein sûlubility €rom the meaI (Gillberg and Tornell. 1976: Tzeng et ai.. 1988a, b and 1990a.…”

“…Further process development showed, that ultrafiltration alone, in either single-stage or multi-stage mode had little effect on the yield and quality of final products (Tzeng, 1987). Tzeng et al (1988a) used a processing scheme which included protein extraction by aqueous sodium hexarnetaphosphate (SHMP) solution followed by ultrafiltration and diafiltration to produce a protein isolate with a protein content of about 90% and a protein recovery of 63%-It was almost free of glucosinolates and low in phytates (<2%). In the same year, another process for rapeseed protein isolation was developed in our laboratories (Tzeng et al, 1988b), comprising extraction with an aqueous SKMP or NaOH solution, ultrafiltration, isoelectric precipitation at pH 3-5, and diafiltration.…”

Processing Foods without Soybean Ingredients

“…Although China is the world ' s largest rapeseed producer, Canada is the leader in large -scale production of improved rapeseed varieties, called " canola, " which are low in both erucic acid ( < 2%) and glucosinolate ( < 30 μ mol/g) [127] . After oil extraction, canola meal contains about 38% protein compared with the 44% protein content of soybean meal [128] .…”

“…The proteins are rich in lysine and contain adequate quantities of the essential amino acids methionine and cystine, which are the limiting amino acids in most cereal and other oilseed proteins, such as soybean [128] . The protein effi ciency ratio of rapeseed/canola meal is 2.64 as compared with 2.19 for soybean [132] .…”

Comparison of biological value and technological properties of oil seed proteins

“…To decrease glucosinolates content in rapeseed and canola meal Diosady et al had used two stage extractions of oils from seeds using polar and nonpolar solvent [17][18][19]. In spite of this method did not promote complete oil recovery from seeds, protein isolates and concentrates obtained from such meal did not contain glucosinolates [20][21][22][23][24]. In addition steam explosion was used for detoxification of rapeseed meals [25] and it was shown that enzyme treatment could be used to decrease of glucosinolates content in meal [26] .…”