Rapeseed proteins

Table XII. Kidney calcium in rats fed casein and rapeseed protein concentrates for 16 weeks (yg/g dry weight)...

Rapeseed. Methods employed in processing of rapeseed protein products influence emulsion capacities (48, 49). Kodagoda et al. (48) showed that rapeseed protein isolates from water extracts emulsified more oil than isolates from acid or alkali extracts (Table VIII). Rapeseed isolates emulsified more oil than their concentrate counterparts. Rapeseed isolates and concentrates from acid extracts were far superior in emulsion stability to rapeseed protein products from water or alkali extracts. 

Table IX. Emulsion capacity of rapeseed protein products.

Processing of Rapeseed Protein and Amino Acid Avail-... 

Hermansson et al. (36) used pepsin and papain to solubilize rapeseed protein concentrate. Papain had a lower solubilizing effect than did pepsin. However, the fact that pepsin has an optimum pH for activity at about 1.6, far below the pH range of most foods, made it possible to study the effects of controlled hydrolysis. At pH 7.0, all hydrolysates were more soluble than the original rapeseed protein concentrate. 

Hermansson et al. (36) examined the stability ratings for protease-treated emulsions of rapeseed protein concentrate at pH... 

Pepsin and papain hydrolysates of rapeseed protein concentrate increased foam volumes and decreased drainage compared to the untreated control (36). Foaming properties could be further enhanced by adding a stabilizer such as carboxymethylcellulose. 

Rapeseed. one of the five most widely produced oilseeds, is cultivated mainly in India. Canada, Pakistan, France, Poland, Sweden, and Germany. Past objections to using rapeseed as a source of edible protein has been its content of deleterious glucosinolales. Considerable research has been conducted in Sweden to develop a rapeseed protein concentrate. The first full-scale production plant using a new process was installed in Alberta, Canada. The plant, with a capacity of 5000 tons/year produces a material containing 65% protein. Rapeseed is rich in essential amino acids, with exception of methionine, which soybeans also lack. 

Deparis V, Durrieu C, Schweizer M, Marc I, Goergen Jl, Chevalot I, Marc A (2003), Promoting effect of rapeseed proteins and peptides on Sf9 insect cell growth, Cytotechnology 42 75-85. 

Soya proteins mid derivatives (globulin 7s, globulin 11s) Rice and manioc proteins Pea proteins Peanut (conarachin), pistachio, cotton, sunflower, and rapeseed proteins... 

Qvist I.H. and von Sydow E.C.F. (1976) Unconventional proteins as aroma precursors. Chemical analysis of the volatile compounds in unheated and heated rapeseed protein model systems. J. Agric. Food Chem. 24, 437 42. 

Hermansson et al. (19) determined the effects of pepsin and papain treatments on the solubility of rapeseed protein concentrate (RPC). The original RPC had a solubility of 11-12% at pH values between 4.0 and 7.0. However, hydrolysis with pepsin for 24 hr increased the solubility to 82-90% over this same pH range. On the other hand papain digestion increased the solubility to only 38-43%. 

Multiple regression analysis performed for succinylated rapeseed protein isolates indicated that emulsification activity was related to protein solubility, hydrophobicity, zeta potential, and flow behavior of aqueous dispersions of the proteins. Emulsion stability was affected by protein solubility, zeta potential, apparent viscosity of protein dispersions, and difference in density between aqueous and oil phases [76],... 

Inconsistent data on foaming properties of rapeseed protein concentrates and isolates [74,75] underline the important influence of the technological process used to obtain the protein preparations upon FC. Thus native rapeseed globulin, which gave a very high FC comparable to that of napin, did not show a reduction of FC after moderate or high succinylation [75], Succinylation of rapeseed meal prior to protein extraction resulted, however, in modified isolates with poor foaming properties [74],... 

Food proteins are important in determining the characteristics of many food products. Frequently the protein used influences more than one characteristic of the food. The protein selected will vary as a function of the protein, the formulation of the food, and the processing of the product. The most common proteins used as food ingredients include egg proteins [83,84], soy proteins [85,86], milk proteins [87,88,89], wheat gluten [90], and fish proteins [91]. Other proteins have been used to a lesser degree and include rapeseed protein, sunflower protein, pea protein, cottonseed protein, peanut protein, and blood plasma. 

After the oil has been extracted from rapeseed, the meal that remains contains 34-38% protein (at 8% moisture level). The amino acid balance of rapeseed protein is quite favorable however, the use of rapeseed meal in animal rations has been limited by its glucosinolate content (Bowland et ai, 1965). The antinutritional and goitrogenic cleavage products from these glucosinolates have a pungent taste that decreases the palatability of the feed. 

The protein sources, a soybean protein isolate (Promine F, Central Soya, Chic.) and a rapeseed protein concentrate (prepared by FRI-71 process at the Food Research Institute, Agriculture Canada, Ottawa) were suspended (10% W/V) in 0.1 N NaOH and heated at 60 C for 4 or 8 h with continuous agitation. Treatment was stopped by the rapid addition of 6 N HCl followed by cooling, adjustment of pH to 4.5, and centrifugation for 15 min at... 

Total nitrogen liberated as small peptides or free amino acids (dialysate) was lower in rapeseed protein, but was not... 

Finally, the initial rate of release of LAL was slower in rapeseed protein, although the total amount hydrolyzed within 24 h was equal or higher than in soybean protein. 

Table II shows the effect of alkali treatment on some other amino acid digestibility. The hydrolytic release rate for individual amino acids was different from the mean rate of release for protein nitrogen and varied according to the protein. For example, lysine from rapeseed protein was liberated slowly. Lysine was more available from soybean protein and its release rate was equivalent to that of serine. The latter amino acid is equally available from both protein sources.

It is noteworthy that the reduction or elimination of glucosi-nolates from rapeseed meal also results in more effective use of the favorable amino acid balance of rapeseed protein. 

Until now, rapeseed meal has been used almost solely as a protein supplementfor animals. With the development of glu-cosi no late-free rapeseed meal, it is expected that rapeseed protein will join soybean protein as an ingredient in meat analogs, meat extenders, dairy products, bakery goods, and other processed foods. 

FIGURE 4.2 Effect of pH on nitrogen solubility index of rapeseed protein isolates. PPI—precipitated protein isolate SPI—soluble protein isolate. (From Xu, L. and Diosady, L. L. 1994. J. Amer. Oil Chem. Soc. 71 935-939. With permission.)... 

---