In‐vitro protein and sulphur amino acid availability as a measure of bean protein quality

Abstract

The total and 'available' cystine and methionine, and the in-vitro and in-vivo protein digestibilities were determined in six varieties of Phaseolus vulgaris with different seed coat colours. Reactive cystine and methionine, evaluated by chemical methods after in-vitro enzymic digestion, were taken as a measure of the availability of sulphur amino acids. Cystine 'availability' ranged from 43 to 51 YO and from 3 1 to 58 YO in raw and cooked samples, respectively, while methionine 'availability' was over 90%, except for the two red varieties (55% and 74%). No correlation was found between cystine and methionine 'availability' and in-vitro protein digestibility. In-vitro protein digestibility (76.6-80.7 YO) showed a good correlation (r = 0857; P c 0.05) with in-vivo values (724-80.9 YO). Amino acid score corrected for protein digestibility and for sulphur amino acids availability, as suggested by the Codex Committee on Vegetable Proteins, seems to predict accurately the biological quality of bean protein, as was shown when in-vitro indices were compared with net protein utilisation and relative protein value.

Nutritional and Physicochemical Characterisation of Italian Rice Flours and Starches

“…*** Sum of essential amino acids. Means in the same row with different letter are significantly different (p < 0.05) most foods show a low buffer properties and this explain the good correlation found with in vivo procedures (Marletta et al, 1992). In any case, in vitro test are suitable to evaluate samples of the same kind as those examined in this paper.…”

In vivo and in vitro protein digestibility of formulated feeds for Artemesia longinaris (Crustacea, Penaeidae)

“…In in vitro methods, the reactions are more drastic than those that occur during the natural digestion of crustaceans and will free nutrients otherwise unavailable (Anderson et al, 1993). Similarly, there is a tendency to overestimate the digestibility of leguminous plants by in vitro methods compared with in vivo methods (Marletta et al, 1992). On the other hand, the results of in vivo methods may be affected by the environmental conditions (temperature, salinity, pH) (Ezquerra et al, 1997).…”

7S Globulins fromPhaseolus vulgarisL.: Impact of Structural Aspects on the Nutritional Quality

“…Indeed, methionine and cysteine are the first limiting amino acids in 7S globulins, with a chemical score of 0.48, followed by tryptophan (chemical score of 0.73) ( Table 2 High-molecular-weight standards (HM, from 205000 to 36000) and low-molecular-weight standards (LM, from 66000 to 14000) are described in the Materials and Methods section. 21) has indicated a low nutritional value of proteins in P. vulgaris seeds, the values for NPU and RPV being 0.41 and 0.39, respectively (Table 2). This has been ascribed to several factors, including the limited amount of sulphur amino acids, poor digestibility and low bioavailability of essential amino acids.…”