Table 2.
Protein quality of whey and selected vegetable protein sources.
| Protein | PDCAAS 1 | PDCAAS 2 | PDCAAS 3 | PDCAAS 4 | DIAAS 3 | Limiting Amino Acid(s), When Present | AA Profile: Materials Analyzed and References | Fractional Digestibility and References |
|---|---|---|---|---|---|---|---|---|
| Milk | 1.00 | 1.00 | 1.00 | 1.00 | 1.08 | None | Milk PC [20,21] | Fecal true protein: mean 0.96 [13,20] Ileal AA: range for individual AA 0.84–0.94 [22] |
| Whey | 1.00 | 1.00 | 0.97 | 1.00 | 0.90 | His | Whey PI [20,21,23] Whey PC [20,21] |
Fecal true protein: mean 0.96 [20,24] Ileal AA: range for individual AA 0.89–1.00 [22] |
| Soy | 0.99 | 1.00 | 0.93 | 1.00 | 0.92 | SAA | Soy PI, Soy PC [25] Soy PI [20] Soy PI [21] |
Fecal true protein: mean 0.97 [13,20,21,25] Ileal AA: range for individual AA 0.95–0.99 [22] |
| Canola | 0.88 | 1.00 | 0.93 | 1.00 | NA | AAA | Canola PI [26]; Canola PI [27] |
Fecal true protein: mean 0.95 [26,27] |
| Potato | 0.87 | 1.00 | 0.87 | 1.00 | 0.85 | His | Solanic 100F Potato PI [28] Solanic 206P HMW and LMW [29] Potato protein [30] Potato juice protein concentrate [31] Avg of 6 potato varieties [32] |
Fecal true protein: 0.89 [24] Ileal AA: range for individual AA 0.73–0.90 [22] |
| Pea | 0.83 | 0.84 | 0.78 | 0.91 | 0.66 | SAA *, Trp | Pea PC [33] Pea PC [21] Pea PC [20] |
Fecal true protein: mean 0.97 [20,21,33] Ileal AA: range for individual AA 0.83–0.90 [20] |
| Quinoa | 0.78 | 0.89 | 0.77 | 0.84 | NA | Ile, Leu, Lys *, Thr, Val | Quinoa, raw [34] Quinoa [35] Quinoa from Salta [36] Uncooked quinoa [37] Field grown quinoa [38] Raw and unwashed quinoa [39] |
Fecal true protein: mean 0.89 [39,40] |
| Chickpea | 0.77 | 0.85 | 0.71 | 0.71 | 0.69 | Leu, Lys, SAA *, Thr, Trp, Val | Boiled chickpeas [41] | Fecal true protein: 0.85 [42] Ilea AA: range for individual AA 0.72–0.9 [22] |
| Lentils | 0.73 | 0.73 | 0.68 | 0.80 | 0.75 | Leu, SAA *, Thr, Trp, Val | Lentils, mature seeds, ckd, bld without salt [37] | Fecal true protein: 0.85 [24] Ileal AA: range for individual AA 0.82–0.98 [22] |
| Red Kidney beans | 0.68 | 0.68 | 0.63 | 0.74 | 0.61 | Leu, Lys, SAA *, AAA, Thr, Trp, Val | Red kidney beans, cnd, drnd solids [37] | Fecal true protein: 0.81 [24] Ileal AA: range for individual AA 0.72–0.94 [22] |
| Fava/faba | 0.63 | 0.65 | 0.60 | 0..67 | NA | Lys, SAA *, Thr, Trp, Val | Fava bean PI [43] Cooked fava beans [44] Broadbeans, ckd [37] 8 faba cultivars [45] Faba bean PI [46] |
Fecal true protein: 0.86 [47] |
| Barley | 0.63 | 0.71 | 0.64 | 0.76 | 0.50 | Lys * | Barley, pearled [48] | Fecal true protein: 0.98 [49] Ileal AA: range for individual AA 0.76–0.83 [22] |
| Pinto beans | 0.61 | 0.61 | 0.57 | 0.66 | NA | His, Ile, Leu, Lys, SAA *, AAA, Thr, Trp, Val | Pinto beans, cnd, drnd solids [37] | Fecal true protein: 0.73 [24] |
| Rice | 0.53 | 0.60 | 0.54 | 0.64 | 0.52 | Lys *, Thr | Rice PC [50] Rice endosperm protein [51] Oryzatein 90 and 80 Rice protein [52] Rice PC [21] |
Fecal true protein: mean 0.90 [21,24,51] Ileal AA: mean ranges for individual AA 0.81–0.87 [21,22] |
| Oat | 0.51 | 0.59 | 0.52 | 0.62 | 0.44 | Lys *, Thr | Oat PC [53]; Rolled oats [21] |
Fecal true protein: 0.91 [13] Ileal AA: range for individual AA 0.70–0.85 [22] |
| Peanut | 0.46 | 0.52 | 0.47 | 0.55 | 0.47 | Ile, Leu, Lys *, SAA, Thr, Trp, Val | Peanut PC and PI [54] Roasted peanuts [21] |
Fecal true protein: 0.93 [24] Ileal AA: mean ranges for individual AA 0.82–0.96 [21,22] |
| Wheat | 0.45 | 0.51 | 0.46 | 0.54 | 0.39 | Ile, Leu *, Lys *, AAA, Thr *, Val | Whole meal and white flour [55] Wheat bran [21] |
Fecal true protein: mean 0.94 [24] Ileal AA: mean ranges for individual AA 0.81–0.91 [22] (wheat bran, wheat flour, wheat gluten, wheat) |
| Corn | 0.41 | 0.47 | 0.42 | 0.50 | 0.38 | Ile, Lys *, SAA, Thr *, Trp*, Val | Corn meal [56] Corn tortillas [57] |
Fecal true protein: 0.84 [24] Ileal AA: ranges for individual AA 0.75–0.88 [22] |
1 FAO FN Paper 51 1989, ages 2–5 year, AA ref standard (mg/g protein) [13]: His 19, Ile 28, Leu 66, Lys 58, SAA 25, AAA 63, Thr 34, Trp 11, Val 35. 2 IOM 2002/2005, ages 1+ year, AA ref standard (mg/g protein) [11]: His 18, Ile 25, Leu 55, Lys 51, SAA 25, AAA 47, Thr 27, Trp 7, Val 32. 3 FAO FN Paper 92 2011, ages 0.5–3 year, AA ref standard (mg/g protein) [16]: His 20, Ile 32, Leu 66, Lys 57, SAA 27, AAA 52, Thr 31, Trp 8.5, Val 43. 4 FAO FN Paper 92 2011, older child, adolescent, adult, AA ref standard (mg/g protein) [16]: His 16, Ile 30, Leu 61, Lys 48, SAA 23, AAA 41, Thr 25, Trp 6.6, Val 40. PDCAAS, Protein Digestibility Corrected Amino Acid Score; DIAAS, Digestible Indispensable Amino Acid Score; AA, amino acid; His, histidine; Ile, isoleucine; Leu, leucine; Lys, lysine; SAA, sulfur amino acids (methionine and cysteine); AAA, aromatic amino acids (phenylalanine and tyrosine); Thr, threonine; TRP, tryptophan; Val, valine; PI, protein isolate; PC, protein concentrate; bld, boiled; ckd, cooked; cnd, canned; drnd, drained. * Limiting amino acid by all four amino acid reference standards.