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Whilst the emulsifying properties of the protein fraction of vicia fabu are almost independent on the acetylation degree, the shear modulus of the gels produced by heat denaturation increases at first with increasing acetylation degree, decreases with further increase of the acetylation, and comes finally to zero for very high acetylation degrees.By changes of pH and by influence of added NaC1, CaCI,, AICI,, and starch, the shear modulus of gels of acetylated protein fractions of vicia f u h can be increased, by addition of sunflower oil it can be decreased.On the base of studies on the fraction p d i l e and on the changes of the content of sulthydryl and disulfide groups of the protein fractions of vicia fabo and the corresponding gels in dependence on the acetylation degree, an interpretation of the results is given, As a continuation of our already published results on the modification of the functional properties of vicia faba proteins by acetylation [l] this paper contains results on emulsifying and gel properties of vicia faba proteins in dependence on the degree of acetylation and on other influencing factors. Material and methodsThe acetylated fractions of viciajiaba protein which are very soluble in water (I) (degree of acetylation: 42, 78.92, and 97 :d) and the corresponding non-acetylated fraction of vicia faha protein (11) were prepared as described previously [I] from an viciafaba protein isolate (111).The acetylation degree of the proteins is given as the percentage of the blocked lysine and has been determined according to [2,3].The determination of the content of sulfhydryl and disulfide groups has been carried out by an amperometric technique described in [4].The gel chromatographic investigations were accomplished using Sepharose 6 B (Pharmacia, Sweden) in a 9/50 column with glass filter, combined with a 21 15 type Multiperpex peristaltic pump (LKB, Sweden) and an Uvicord I1 spectrophotometer (LKB, Sweden); 5.0 mg protein in 1.0 ml solution were given on the column. The flow rate was 6 ml/h and the fraction size 2 ml. To estimate the molecular masses a calibration was carried out with cytochrom C, chymotrypsinogen A, ovalbumin (SERVA, Heidelberg) and bovine serum albumin (FERAK, Berlin-West). The proteins were separated in borate buffer (pH 8.4; p = 0.25), in borate buffer (pH 8.4: p = 0.25 + 0.1 % sodium dodecylsulfate), and in borate buffer (pH 8.4 p = 0.25 + 0. I 7; sodium dodecylsulfate -4-0.1 % 2-mercaptoethanol).

N digestibility and the dietary quality of a Vicia faba protein isolate as well as of two protein fractions from this isolate, acetylated and nonacetylated, were estimated in ¹⁵N-labelled adult rats. For reference, whole egg, casein and wheat were studied. The diets were fed at maintenance energy intake level. Daily metabolic fecal nitrogen estimated by an isotopic method was 5 mg/l00 g body weight in animals receiving whole egg, casein, or Vicia faba proteins. When wheat was included in the diet metabolic fecal nitrogen was increased to 140% of this value. True N digestibility of reference proteins was 91-92% and of Vicia faba proteins 95-97%. Protein quality for maintenance was high and similar for all proteins. Acetylation affected neither N digestibility nor protein quality under maintenance conditions.

Preparation of broad bean (Viciafaba L. minor) products Part. I. Broad bean protein isolates from seed flour and their acetylation in the neutral pH range CH. SCHNEIDEII. M . SCIIIILTZ and H. SCHMANDKE I t is possible to prepare broad bean protein isolates with a high yield directly from seed flour using a wet process. This process involves an aqueous extraction at pH 7.5 followcd by separalion of thc insoluble residue and isoelectric precipitation of the protein from the aqueous extract.Following the same principle is it possible to prepare acetylated broad bean protein isolates with any adjustable acetylation degree. For that acetic anhydride is to be added and the adjusted pH is to be maintained during the extraction. In both cases the yield of the protein is mainly determincd by the used solid-liquid ratio.